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Charles darwin.

Charles Darwin and his observations while aboard the HMS Beagle , changed the understanding of evolution on Earth.

Biology, Earth Science, Geography, Physical Geography

Historic photograph of Charles Darwin in profile.

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Charles Darwin was born in 1809 in Shrewsbury, England. His father, a doctor, had high hopes that his son would earn a medical degree at Edinburgh University in Scotland, where he enrolled at the age of sixteen. It turned out that Darwin was more interested in natural history than medicine—it was said that the sight of blood made him sick to his stomach. While he continued his studies in theology at Cambridge, it was his focus on natural history that became his passion.

In 1831, Darwin embarked on a voyage aboard a ship of the British Royal Navy, the HMS Beagle, employed as a naturalist . The main purpose of the trip was to survey the coastline of South America and chart its harbors to make better maps of the region. The work that Darwin did was just an added bonus.

Darwin spent much of the trip on land collecting samples of plants, animals, rocks, and fossils . He explored regions in Brazil, Argentina, Chile, and remote islands such as the Galápagos. He packed all of his specimens into crates and sent them back to England aboard other vessels.

Upon his return to England in 1836, Darwin’s work continued. Studies of his samples and notes from the trip led to groundbreaking scientific discoveries. Fossils he collected were shared with paleontologists and geologists, leading to advances in the understanding of the processes that shape the Earth’s surface. Darwin’s analysis of the plants and animals he gathered led him to question how species form and change over time. This work convinced him of the insight that he is most famous for— natural selection . The theory of natural selection says that individuals of a species are more likely to survive in their environment and pass on their genes to the next generation when they inherit traits from their parents that are best suited for that specific environment. In this way, such traits become more widespread in the species and can lead eventually to the development of a new species .

In 1859, Darwin published his thoughts about evolution and natural selection in On the Origin of Species . It was as popular as it was controversial. The book convinced many people that species change over time—a lot of time—suggesting that the planet was much older than what was commonly believed at the time: six thousand years.

Charles Darwin died in 1882 at the age of seventy-three. He is buried in Westminster Abbey in London, England.

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Charles Darwin

(1809-1882)

Who Was Charles Darwin?

Charles Robert Darwin was a British naturalist and biologist known for his theory of evolution and his understanding of the process of natural selection. In 1831, he embarked on a five-year voyage around the world on the HMS Beagle , during which time his studies of various plants and an led him to formulate his theories. In 1859, he published his landmark book, On the Origin of Species .

Darwin was born on February 12, 1809, in the tiny merchant town of Shrewsbury, England. A child of wealth and privilege who loved to explore nature, Darwin was the second youngest of six kids.

Darwin came from a long line of scientists: His father, Dr. R.W. Darwin, was a medical doctor, and his grandfather, Dr. Erasmus Darwin, was a renowned botanist. Darwin’s mother, Susanna, died when he was only eight years old.

His father hoped he would follow in his footsteps and become a medical doctor, but the sight of blood made Darwin queasy. His father suggested he study to become a parson instead, but Darwin was far more inclined to study natural history.

While Darwin was at Christ's College, botany professor John Stevens Henslow became his mentor. After Darwin graduated Christ's College with a bachelor of arts degree in 1831, Henslow recommended him for a naturalist’s position aboard the HMS Beagle .

The ship, commanded by Captain Robert FitzRoy, was to take a five-year survey trip around the world. The voyage would prove the opportunity of a lifetime for the budding young naturalist.

On December 27, 1831, the HMS Beagle launched its voyage around the world with Darwin aboard. Over the course of the trip, Darwin collected a variety of natural specimens, including birds, plants and fossils.

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Darwin in the Galapagos

Through hands-on research and experimentation, he had the unique opportunity to closely observe principles of botany, geology and zoology. The Pacific Islands and Galapagos Archipelago were of particular interest to Darwin, as was South America.

Upon his return to England in 1836, Darwin began to write up his findings in the Journal of Researches , published as part of Captain FitzRoy's larger narrative and later edited into the Zoology of the Voyage of the Beagle .

The trip had a monumental effect on Darwin’s view of natural history. He began to develop a revolutionary theory about the origin of living beings that ran contrary to the popular view of other naturalists at the time.

Theory of Evolution

Darwin’s theory of evolution declared that species survived through a process called "natural selection," where those that successfully adapted or evolved to meet the changing requirements of their natural habitat thrived and reproduced, while those species that failed to evolve and reproduce died off.

Through his observations and studies of birds, plants and fossils, Darwin noticed similarities among species all over the globe, along with variations based on specific locations, leading him to believe that the species we know today had gradually evolved from common ancestors.

Darwin’s theory of evolution and the process of natural selection later became known simply as “Darwinism.”

At the time, other naturalists believed that all species either came into being at the start of the world or were created over the course of natural history. In either case, they believed species remained much the same throughout time.

'Origin of Species'

In 1858, after years of scientific investigation, Darwin publicly introduced his revolutionary theory of evolution in a letter read at a meeting of the Linnean Society . On November 24, 1859, he published a detailed explanation of his theory in his best-known work, On the Origin of Species by Means of Natural Selection.

In the next century, DNA studies provided scientific evidence for Darwin’s theory of evolution. However, controversy surrounding its conflict with Creationism — the religious view that all of nature was born of God — is still found among some people today.

Social Darwinism

Social Darwinism is a collection of ideas that emerged in the late 1800s that adopted Darwin’s theory of evolution to explain social and economic issues.

Darwin himself rarely commented on any connections between his theories and human society. But while attempting to explain his ideas to the public, Darwin borrowed widely understood concepts, such as “survival of the fittest” from sociologist Herbert Spencer.

Over time, as the Industrial Revolution and laissez faire capitalism swept across the world, social Darwinism has been used as a justification for imperialism, labor abuses, poverty, racism, eugenics and social inequality.

Following a lifetime of devout research, Charles Darwin died at his family home, Down House, in London, on April 19, 1882. He was buried at Westminster Abbey .

More than a century later, Yale ornithologist Richard Brum sought to revive Darwin's lesser-known theory on sexual selection in The Evolution of Beauty .

While Darwin's original attempts to cite female aesthetic mating choices as a driving force of evolution was criticized, Brum delivered an effective argument via his expertise in birds, earning selection to The New York Times ' list of 10 best books of 2017.

QUICK FACTS

• Name: Charles Darwin
• Birth Year: 1809
• Birth date: February 12, 1809
• Birth City: Shrewsbury
• Birth Country: England
• Gender: Male
• Best Known For: Charles Darwin was a British naturalist who developed a theory of evolution based on natural selection. His views and “social Darwinism” remain controversial.
• Science and Medicine
• Astrological Sign: Aquarius
• University of Edinburgh
• Interesting Facts
• Although Charles Darwin originally went to college to be a physician, he changed career paths when he realized that he couldn't stomach the sight of blood.
• Charles Darwin had a mountain named after him, Mount Darwin, in Tierra del Fuego for his 25th birthday. The monumental gift was given by Captain FitzRoy.
• Death Year: 1882
• Death date: April 19, 1882
• Death City: Downe
• Death Country: England

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CITATION INFORMATION

• Article Title: Charles Darwin Biography
• Author: Biography.com Editors
• Website Name: The Biography.com website
• Url: https://www.biography.com/scientists/charles-darwin
• Access Date:
• Publisher: A&E; Television Networks
• Last Updated: March 29, 2021
• Original Published Date: April 3, 2014
• A man who dares to waste one hour of time has not discovered the value of life.
• [How great the] difference between savage and civilized man is—it is greater than between a wild and [a] domesticated animal.
• If all men were dead, then monkeys make men. Men make angels.
• I am a complete millionaire in odd and curious little facts.
• Multiply, vary, let the strongest live and the weakest die.
• For the shield may be as important for victory, as the sword or spear.
• I see no good reason why the views given in this volume should shock the religious feelings of anyone."[In 'Origin of the Species']
• A grain in the balance may determine which individuals shall live and which shall die—which variety or species shall increase in number, and which shall decrease, or finally become extinct.
• If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find out no such case.
• The extinction of species and of whole groups of species, which has played so conspicuous a part in the history of the organic world, almost inevitably follows from the principle of natural selection.
• There is grandeur in this view of life...from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.

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Charles Darwin: Biography, Theories, Contributions

Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."

Steven Gans, MD is board-certified in psychiatry and is an active supervisor, teacher, and mentor at Massachusetts General Hospital.

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Biography of Charles Darwin

• Best Known For

Natural Selection and Evolution

• Controversies
• Research on Emotions
• Views on Women
• Contributions

Charles Darwin was a renowned British naturalist and biologist best known for his theory of evolution through natural selection. His theory that all life evolved from a common ancestor is now a cornerstone of modern science, making Darwin one of the most influential individuals in history. It is difficult to overstate the monumental influence his work has had on our scientific understanding of the world.

This article discusses Charles Darwin's life and work, including his famous theory of natural selection as well as some of his lesser-known research on human emotion.

Charles Darwin was born in Shrewsbury, England, on February 12, 1809. His father was a wealthy doctor, and his grandfather on his mother's side was the noted potter Josiah Wedgwood. After his mother’s death when he was eight, Darwin began attending boarding school with his older brother. 

Darwin originally began his studies at the University of Edinburgh Medical School, but later developed an interest in ministry and botany, eventually receiving his degree from Cambridge in 1831.

His famed voyage to the Galapagos Islands led to the observations that served as the basis for Darwin's groundbreaking theory of natural selection.

In 1839, Darwin married his cousin Emma Wedgwood. They had 10 children together, with seven surviving to adulthood. In 1859, he published his observations and ideas in his book "On the Origin of Species By Means of Natural Selection."

Darwin's ideas were heavily debated in his own time and continue to spark controversy today. In contrast to this, Darwin himself lived a secluded life at his home in England, where he continued to work as a highly regarded scientist.

Darwin died on April 19, 1882, and is buried at Westminster Abbey in London, England.

Darwin's Illness

For much of his adult life, Darwin had an undiagnosed chronic illness that limited his activities. Symptoms included physical complaints such as stomach pain and dizziness, as well as signs of panic attacks such as shortness of breath and heart palpitations.

One theory suggests that he may have had panic disorder with agoraphobia . This diagnosis would also explain his secluded lifestyle, difficulty with public speaking, and struggles when meeting with colleagues.

Other proposed diagnoses include mercury poisoning, allergies, Crohn's disease, and irritable bowel syndrome. However, many researchers now believe that he had an adult-onset mitochondrial disorder.

What Was Charles Darwin Most Famous For?

Charles Darwin is most famous for his theory of evolution through the process of natural selection. Since introducing his ideas in “On the Origin of the Species,” his work has revolutionized the scientific understanding of how species evolve over time. This helped lay the foundation for modern biological sciences .

His Studies on the Galapagos Islands

During a voyage on a ship called the HMS Beagle, Darwin traveled to the Galapagos Islands, a journey that had a profound influence on his thinking and ideas. During this trip, he noticed interesting variations in the different species of finches that lived on the islands.

The beaks of these birds appeared to vary depending on the native food sources where the birds lived. Darwin hypothesized that the variations he observed resulted from natural selection that favored birds with beaks suited to the local food sources.  

There are 14 species of finches found on the Galapagos Islands, which are now collectively referred to as "Darwin's finches."

In “On the Origin of the Species,” Darwin suggested that all species on Earth, including humans, evolved from common ancestors. The diversity found in all species, he explained, results from changes that occur gradually over very long periods of time, a process he referred to as “descent with modification.” This happens through natural selection, where certain traits that benefit an organism's survival are more likely to be passed down. 

Because these organisms are more likely to survive and reproduce, those beneficial traits are more likely to be handed down. This leads to the adaptation and evolution of species.

Charles Darwin's concept of evolution through natural selection suggested that species change slowly over time as a response to their environment. This theory changed our scientific understanding of the diversity of life on Earth and laid the groundwork for the development of modern biology.

How Does Natural Selection Work?

According to Darwin, the individuals within a population possess variations, some of which are better suited to the environment in which they live. As a result, those with these adaptations are more likely to survive, reproduce, and thus pass these advantageous characteristics down to their offspring.

Over time, this process gradually leads the adaptive traits to become more prominent and can eventually lead to the emergence of new species.

The Five Principles of Natural Selection

The five principles of natural selection described by Charles Darwin can be remembered using the acronym VISTA, standing for variation, inheritance, selection, time, and adaptation.

• Variation : In all populations of any species, there are individual variations in different traits. The species' members can vary in appearance, size, abilities, immunity, and numerous other characteristics. Many of these variations result from genetic inheritance but can also occur due to random mutations.
• Inheritance : The various traits organisms possess can be inherited through genetic inheritance. In other words, when members of a species reproduce, their offspring are more likely to also possess those same traits.
• Selection : Environmental resources are limited, so organisms with advantageous characteristics that make it easier for them to survive are more likely to thrive in their environment and reproduce. This increased chance of reproduction means that their children are more likely to have the same traits that helped their ancestors survive.
• Time : As time passes, each generation continues to produce more offspring with advantageous characteristics. With the passage of time, the beneficial traits continue to accumulate, resulting in significant changes in the characteristics of the entire population.
• Adaptation : Such traits eventually become more common in the population, making the entire species better suited to survive in their environment.

What Does ‘Survival of the Fittest’ Mean?

An important part of natural selection is the idea of ‘survival of the fittest.’ The phrase was first introduced in 1854 by Herbert Spencer in his book "The Principles of Biology."

The idea suggests that when it comes to each organism's struggle to survive and reproduce, those with traits that make them the best suited to their environment are the most likely to survive and pass down their genes to the next generation.

In this context, "fitness" refers to an organism's ability to survive in its environment and reproduce. It is the traits that help the individual survive that are considered most advantageous. 

Fitness does not refer to physical strength. Instead, it means the individual has traits that make them better suited for life in a specific environment. For example, an organism with coloring that camouflages it from predators would be considered a better fit, from an evolutionary perspective, than coloring that makes it more susceptible to becoming prey.

Fitness can refer to a wide variety of characteristics. This might include physical attributes such as camouflage, speed, strength, or agility. It might also refer to behavioral adaptations that confer a greater chance of survival. Migration, hibernation, and courtship behaviors are a few examples of behavioral adaptations influenced by evolution.

Controversies Surrounding Darwin’s Theory of Evolution

Darwin's theory was considered shocking and controversial after its introduction. While the theory is accepted by nearly all scientists today, Darwin's ideas are still disputed or rejected by some people.

Darwin and his work have remained controversial in the more than 140 years since his death. One survey found that a third of U.S. adults reject the idea that humans evolved through natural selection, views that correspond with rates of religious belief.

One critic during Darwin's time was the English comparative anatomist and paleontologist Richard Owen. While Owen agreed that evolution occurred, he was a vocal critic of Darwin's idea of natural selection. Instead, he proposed the existence of predetermined "archetypes" that guide the evolutionary changes that species experience. 

During Darwin's time, some critics suggested that the lack of transitional fossils (demonstrating the gradual progression of a species over time) was evidence that Darwin’s evolutionary theory was wrong. In the subsequent years, however, many of these so-called "missing links" have been added to the fossil record, providing paleontological support for these evolutionary transitions.

Other critics focus on their belief that all life results from divine creation. However, it is important to note that Darwin's theory of evolution does not focus on how life originated. Instead, Darwin's theory of natural selection explains how life evolved over time and how this explains the diversity of life on Earth.

While there have been debates and criticisms from various sources, it is important to note that Darwin was highly regarded in his own time. Support from the scientific community continued to build over the years, and more evidence supporting Darwin's theory accumulated from various fields.

Charles Darwin’s Research on Human Emotions

While Darwin is best known for his theory of evolution, he also studied and wrote about a wide range of topics, from plants to sea life. Beyond his work as a naturalist, he also conducted one lesser-known experiment on the study of human emotions , making him one of the earliest experimental psychology researchers. 

In archival research looking at Darwin's letters and other writings, researchers found references to a small experiment that Darwin had conducted at home. Darwin had corresponded with the French physician Guillaume Duchenne de Boulogne, who had used electrical impulses to stimulate facial muscles into specific expressions, which were then recorded on photographic plates. Using this method, Duchenne suggested that the human face is capable of expressing at least 60 distinct emotions.

Darwin disagreed. Using Duchenne's plates, Darwin devised his own experiment, a single-blind study in which he randomized the order of the plates and then presented them to over 20 participants (i.e., Darwin's guests). He then asked his guests to identify the emotions represented in the photographic slides. 

In studying Darwin's notes, researchers discovered that the participants agreed when it came to the basic emotions , such as happiness , surprise, and fear. For more ambiguous photographs, responses were much more mixed.

In Darwin's view, only those emotions that were readily identifiable and agreed upon by observers represented universal emotions.

Darwin's observations and conclusions in this and other studies he conducted helped inform his 1872 book "The Expression of the Emotions in Man and Animals." In this book, Darwin emphasized the importance of emotional expression in both humans and animals, suggesting that:

• Some emotional expressions are universal
• Some emotions have a biological, evolutionary basis
• These universal expressions evolved through natural selection because they aid in survival, reproduction, and communication
• Humans and animals display similar emotions, suggesting they have a common evolutionary origin

Darwin's work offered insights into the importance of emotions, their evolutionary roots, and their universality across cultures and species . His observations also helped lay the groundwork for future research on the psychology of human emotions.

However, Darwin's ideas about emotion were eclipsed by his more famous theory of natural selection. It wasn't until the 1960s that psychologist Paul Ekman returned to Darwin's findings and, using methods similar to those originally pioneered by Darwin, found additional evidence for the existence of basic, universal human emotions.

Try the emotion experiment yourself!

The Darwin Correspondence Project allows viewers to see the original photographic plates Duchenne and Darwin used this in their experiments. You can also give your own response and see how your interpretation compares to those of Darwin's guests.

What Were Charles Darwin’s Views on Women?

While Darwin revolutionized the field of science, his views on women were far from progressive. His attitudes reflected the prevailing sexist, misogynistic ideas of his time. In his published writings, he echoed the societal and cultural beliefs that women were inferior to men, viewing them as less intelligent.

In his book "The Descent of Man," Darwin wrote, "Woman seems to differ from man in her mental disposition, chiefly in her greater tenderness and less selfishness."

Darwin suggested that the purported superiority of men stemmed from sexual selection, a mode of natural selection in which men compete for mates, leading to the evolution of characteristics that improve their reproductive fitness, including intelligence, physical strength, and competitiveness.

He believed that women's roles were primarily as domestic caretakers and nurturers, which, in his view, did not require strong intellectual capabilities.

There is evidence that Darwin's ideas changed somewhat over time, often influenced by the women in his life, including his wife, daughters, and women intellectuals. While he could not be regarded as a feminist thinker, research on his private correspondence suggests that his views on women were more complex than what appears in his published writing.

Who Did Charles Darwin Influence?

In addition to his profound influence on the biological sciences, Darwin inspired a number of other scientists and researchers in their own work.

Some of these thinkers included:

• Alfred Russel Wallace : A contemporary of Darwin, Wallace was an English naturalist and explorer who independently introduced the idea of evolution through natural selection. His own ideas were published in 1858 along with some of Darwin's earlier writings, prompting Darwin to publish "On the Origin of the Species" the next year.
• William James : The founder of the functionalist school of thought in psychology was heavily influenced by the work of Charles Darwin. This school of thought suggests that the functions of the mind exist because they serve a purpose in survival and adaptation. This idea has its roots in Darwin's theory of natural selection. James was also heavily influenced by Darwin's writings on the topic of emotions. According to the James-Lange theory of emotions , emotions stems from the physiological reactions people experience in response to environmental stimuli.
• Ronald A. Fisher : A British mathematician and biologist, Fisher is considered a founder of modern statistical science. He also played an important role in what is known as modern synthesis, which involved integrating Darwin's natural selection with Mendelian genetics in order to explain how genetic variations within a group can be affected by natural selection.

How Does Charles Darwin’s Work Affect Modern Science Today?

It is difficult to overstate the enormous impact of Darwin's work on modern science. Some of the ways that science continues to be impacted by Darwin's theory of evolution include:

• Evolutionary sciences : The theory of evolution plays an essential role in biology as well as other fields that explain how life has adapted and changed over time, including genetics and evolutionary psychology .
• Medicine : Researchers continue to use their understanding of evolutionary science to study how diseases originate, spread, and mutate.
• Scientific education : While Darwin's ideas remain controversial for some, his work has helped advance scientific literacy and understanding among the general public.

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By Kendra Cherry, MSEd Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."

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Charles Darwin: History’s most famous biologist

Charles Robert Darwin (1809-1882) transformed the way we understand the natural world with ideas that, in his day, were nothing short of revolutionary.

He and his fellow pioneers in the field of biology gave us insight into the fantastic diversity of life on Earth and its origins, including our own as a species.

Photograph of Charles Robert Darwin taken at his home, Down House, in 1881.

Charles Darwin is celebrated as one of the greatest British scientists who ever lived, but in his time his radical theories brought him into conflict with members of the Church of England.

Young Charles Darwin

Born in 1809 in Shrewsbury, Shropshire, Darwin was fascinated by the natural world from a young age. Growing up he was an avid reader of nature books and devoted his spare time to exploring the fields and woodlands around his home, collecting plants and insects.

In 1825 Darwin enrolled in medical school at the University of Edinburgh, where he witnessed surgery on a child. Surgeries at the time would have been carried out without the use of anaesthetic or antiseptics, and fatalities were common.

Watching this procedure left Darwin so traumatised that he gave up his studies without completing the course.

During his time in Edinburgh, Darwin also paid for lessons in taxidermy from John Edmonstone , a former enslaved man from Guyana. The skills Edmonstone taught Darwin became crucial just a few years further into his career.

After his time in Scotland, Darwin went to Cambridge University to study theology.

The voyage of HMS Beagle

In no rush to take holy orders, in 1831 Darwin accepted an offer to embark on a five-year voyage aboard HMS Beagle. 

Drawing of H.M.S. Beagle from A Naturalist’s Voyage Round the World by Charles Darwin.

He was recommended by one of his Cambridge professors for the role as naturalist and companion to the ship’s captain, Robert FitzRoy.

The journey would change both his life and the trajectory of Western scientific thinking.

Darwin explored remote regions and marvelled at a world so different from the one he knew. He encountered birds with bright blue feet, sharks with T-shaped heads and giant tortoises.

On his travels Darwin collected plants, animals and fossils, and took copious field notes. These collections and records provided the evidence he needed to develop his remarkable theory.

The shells in this specimen drawer were collected by Charles Darwin during the voyage of the HMS Beagle.

Darwin returned to England in 1836. A highly methodical scholar, constantly collecting and observing, he spent many years comparing and analysing specimens before finally declaring that evolution occurs by a process of natural selection.

What is the theory of natural selection?

To this day the theory of evolution by natural selection is accepted by the scientific community as the best evidence-based explanation for the diversity and complexity of life on Earth.

The theory proposes that the ‘fittest’ individual organisms - those with the characteristics best suited to their environment - are more likely to survive and reproduce. They pass on these desirable characteristics to their offspring.

Gradually these features may become more common in a population, so species change over time. If the changes are great enough, they could produce a new species altogether.

On his travels Darwin had collected finches from many of the Galápagos Islands - off the coast of Ecuador - which helped him to formulate his idea.

Cactus finch Geospiza scandens from Charles Darwin’s Zoology of the Voyage of the H.M.S. Beagle.

Some of these finches had stout beaks for eating seeds, others were insect specialists. But Darwin realised that they were all descendants of a single ancestor. As they dispersed to different islands, the birds had adapted to eat the various foods available. Natural selection had produced 13 different species of finch.

Darwin’s pigeons

From his travels on HMS Beagle, Darwin suspected that the environment might naturally manipulate species, causing them to change over time - but he couldn’t find a means to explore this effectively in the wild. 

Experimenting with artificial selection in pigeons gave him a way to study how far a species could change.

By artificially selecting features - crossing birds with particular characteristics to generate different offspring - he gathered valuable evidence for evolution by natural selection.

To illustrate his theory, Darwin bred the birds to have exaggerated features.

Original line drawing of an English Pouter pigeon from the book Variation in Animals and Plants under Domestication by Charles Darwin.

The similarity between artificial selection and natural selection is at the heart of his explanation of evolution in his revolutionary book On the Origin of Species. 

After completing his experiments, he gave all 120 of his pigeon specimens to the Museum. They are currently part of our bird collections  kept at Tring , Hertfordshire. 

Fancy breeds of rock dove  Columbia livia  donated to our collections by Charles Darwin in 1867.

A shared discovery

Darwin knew his radical ideas would be met with stiff opposition. Even after 20 years of research, he worried about how his theory of evolution would be received as it challenged widely held religious beliefs of the time. 

He delayed publishing on the topic for a great number of years while he assembled a mountain of evidence. When he learned that the young naturalist Alfred Russel Wallace had developed similar ideas, Darwin volunteered to send Wallace's ideas to a journal for immediate publication.

Letter sent to Charles Darwin by Alfred Russel Wallace.

On advice from friends, the two scientists organised a joint announcement. Their theory of evolution by natural selection was presented at the Linnean Society in London.

Both had studied the natural world extensively and made a number of observations that were critical to the development of the theory.

The following year, Darwin published the contentious but now-celebrated book, ‘On the Origin of Species’.

On the Origin of Species

Published in 1859, On the Origin of Species provoked outrage from some members of the Church of England as it implicitly contradicted the belief in divine creation.

Despite accusations of blasphemy, the book quickly became a bestseller.

Foreign language first editions of some works by Charles Darwin.

The Descent of Man, and Selection in Relation to Sex - which Darwin published in 1871 - fuelled even greater debate as it suggested that humans descended from apes.

The Bishop of Oxford famously asked Thomas Huxley, one of Darwin’s most enthusiastic supporters, whether it was through his grandfather or grandmother that he claimed descent from a monkey.

Despite the attacks, Darwin’s conviction in the scientific explanation that best fit the available evidence remained unshaken.

He was keen for his ideas to reach as many people as possible and for his books to be read in many different languages. Part of his success has been attributed to his conversational and approachable writing style.

On the Origin of Species was so influential that within a year it had been published in German. In Darwin's lifetime, his book was translated into German, Danish, Dutch, French, Hungarian, Italian, Polish, Russian, Serbian, Spanish and Swedish. 

Our Library has 478 editions of On the Origin of Species in 38 languages and in Braille.

Japanese translation of On the Origin of Species, Shu No Kigen, published in 1914 as a five-volume, pocket-sized edition.

Darwin and the tree of life

Charles Darwin used the concept of a tree of life in the context of the theory of evolution to illustrate that all species on Earth are related and evolved from a common ancestor.

Darwin’s first sketch of the tree of life, found in one of his notebooks from 1837. Image reproduced with kind permission of the Syndics of Cambridge University Library . 

The tips of the branches show the species that are still alive today. The tree also shows those that are now extinct. Darwin explained:

‘From the first growth of the tree, many a limb and branch has decayed and dropped off; and these fallen branches of various sizes may represent those whole orders, families, and genera which have now no living representatives, and which are known to us only in a fossil state.’

Orders, families and genera are all groups that can be used to classify organisms.

The lines on the tree show evolutionary relationships between species. For example, a recent version of the tree of life would show a line between some types of dinosaurs and the earliest birds, as scientists reason that birds evolved from a particular lineage of dinosaurs.

This means that species that are closely related are found close together stemming from the same branch.

For example, humans, chimpanzees, gorillas and orangutans are all great apes, so they all belong to the same branch of the tree of life.

Darwin’s legacy

Although Darwin’s theory of evolution has been modified over time, it remains fundamental to the study of the natural world. Darwin changed not only the way we see all organisms, but also the way we see ourselves.

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The Museum Library contains the worlds largest collection of works by and about Charles Darwin. 

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AT THE SMITHSONIAN

How darwin’s theory of evolution evolved.

A new Smithsonian Book highlights firsthand accounts, diaries, letters and notebooks from aboard the HMS Beagle

Adrian Lister, Natural History Museum, London

The skulls and bones of extinct mammals were the crowning glory of Charles Darwin’s fossil collecting in South America, not only for him but for the eager recipients of the cargoes he sent home. They were the discoveries that made his name known beyond his immediate circle.

When the first consignment of fossil bones arrived at the Royal College of Surgeons in 1833, the puzzled curator, William Clift, recorded them as apparently “from a Mr Darwin at Rio de la Plata.” Only a few months later, however, after the specimens had been exhibited in Cambridge, Darwin's friend Frederick William Hope wrote to tell him that his “name was in every mouth.” Even more significantly, Darwin later credited the fossil mammals as one of the two main factors that led him to embrace the reality of evolution.

The most complete fossil of any mammal discovered by Darwin was an almost entire skeleton, later recognized as another new species of ground sloth by Richard Owen, a professor at the Royal College of Surgeons who described and named Darwin's fossils. It appears to have been found on the beach, partially embedded in loose sand, and Darwin concluded that the whole mass had fallen from the cliff.

The skeleton comprised the skull, vertebral column, ribs and limb bones down to the claws, “all nearly in their proper relative positions,” including even the kneecaps. This remarkable discovery was first noted by Darwin on September 1, 1833, and must have been made at some point during his second phase of collecting at Punta Alta, Argentina, the previous week.

Darwin quickly recognized the significance of finding an articulated skeleton; whereas odd bones might have been washed out of earlier deposits or fallen in from above, a complete skeleton embedded in sand demonstrated conclusively the contemporaneity of the living animal with the ancient deposit in which it was found. “Gran bestia all nonsense,” he exclaimed in his notebook, referring to a local legend, for it was perfectly clear that the remains were ancient and not those of a mysterious creature that still roamed the Pampas.

He wrote to his sister Caroline that he had discovered the skeleton of an animal “of which I do not think there exists at present on the globe any relation.” Later he wondered if it might represent the same species as the mandible whose four teeth he had previously illustrated, subsequently named Mylodon darwinii . On detailed comparison, however, Owen confirmed it as a different genus, smaller and with a more elongate skull, and named it Scelidotherium leptocephalum.

Another sloth species discovered by Darwin was found in November 1833 during his two-week excursion across present-day Uruguay. It was part of the back of a skull, later named Glossotherium by Owen. The find was made in the same stream, the Sarandi, where a larger, more complete skull of the celebrated mammal Toxodon had been discovered. It is not quite clear whether Darwin himself found the Glossotherium specimen at the stream, or obtained it from the finder together with the Toxodon , although the former seems more likely. At any event the specimen, which Darwin described as from “an animal rather larger than the horse,” was remarkable for its superb state of preservation; he wrote that it appeared “so fresh that it was difficult to believe [it had] lain buried for ages under ground.”

Darwin's Fossils: The Collection That Shaped the Theory of Evolution

Richly illustrated with photos from the fossil collection and line drawings produced when Darwin was alive, Lister’s work is an essential acquisition for every library prizing quality books on evolution.

Not only was the appearance of the bone fresher than any of his other fossil finds, it preserved delicate parts that are usually broken away in ancient remains. This included the tympanic bone, one of the tiny ear bones. Its preservation in place in the skull lead Owen to praise “the care and attention devoted to his specimens by their gifted discoverer.”

Darwin wanted to know more. He held a piece of the bone in the flame of a spirit-lamp, finding that it not only burnt with a small flame, but “exhaled a very strong animal odour.” He sent a piece to Trenham Reeks at the Museum of Economic Geology in London, who had undertaken chemical analyses of several of his rock samples, asking what percentage of animal matter it contained. By this he meant organic material aside from bone mineral, and the answer was 7 percent. We would now recognize that around a quarter of the original protein content had been retained. The remarkable state of preservation of this skull, and its different appearance from others in Darwin’s collection, make it very likely to have fallen from a higher, later level in the river bank than the Toxodon and glyptodont remains found nearby.

Having only a fragment of skull at his disposal, Owen was characteristically cautious and identified it as an edentate without specifying to which group it belonged. A large attachment surface for the bone supporting the tongue, and a wide hole for the nerve supplying the latter, led him to reconstruct a very large tongue and to devise the name Glossotherium (tongue-beast). He later abandoned the name, considering the skull to belong the same species as the jaw that he had named Mylodon darwinii .

It is now recognized as being distinct, however, so Owen’s name has been reinstated and the species is known as Glossotherium robustum . Owen considered the animal might have been an insect-eater, breaking open termite nests like an anteater, but it is now known to have been herbivorous in its habits. Its wide muzzle suggests unselective bulk-feeding on grasses and low-growing herbs.

In 2017, based on collagen protein extracted from Darwin's Glossotherium skull, a radiocarbon date of around 12,660 years ago was obtained. This is one of the latest known records of the genus, close to the time of its extinction. Glossotherium robustum had an estimated body weight of around 1.5 tonnes [1 ton U.S.].

In spite of this, a remarkable recent suggestion is that Glossotherium and/or Scelidotherium may have constructed large burrows to escape predation or unfavorable weather. Several lines of evidence support this idea. First, several large “fossil burrows” have been discovered, especially in the area around Buenos Aires, their diameter of 3 to 4.5 feet matches the body width of these species. Second, the forelimb bones of these animals appear modified for very powerful movements like digging. Third, claw marks have been found on the inside of some of the burrows, forming pairs of grooves that match closely the claws of the large second and third digits seen in these species. These sloths would be by far the largest animals known to burrow in this way—and one of the fossil burrows is more than 130 feet in length.

Darwin’s discovery on this journey of four genera of large ground sloths, Mylodon, Glossotherium, Scelidotherium and Megatherium was remarkable, and also serendipitous in that the area in which he was collecting happened to be the only region where all four could have been found together. Mylodon is distributed in the southern half of the continent, Glossotherium in the northern half, and Scelidotherium in the middle. The genus Megatherium is widespread, but M. americanum is known mainly from Argentina. Only in the Pampas region and La Plata basin do they overlap. The differing forms of their skulls, and teeth and limbs show how several species could have co-existed in the Late Pleistocene, using different food and habitat resources.

For Darwin, the relationship of the extinct giant sloths to the living species was one of the examples that led him to his “law of succession of types,” whereby there was an affinity between the past and present inhabitants of a particular region (in this case South America). This general pattern was one of the key factors that ultimately persuaded him of the reality of evolution.

Darwin’s Fossils: Discoveries that Shaped the Theory of Evolution by Adrian Lister, a research leader in the earth science department at the Natural History Museum, London, is published by Smithsonian Books.

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Darwin: From the Origin of Species to the Descent of Man

This entry offers a broad historical review of the origin and development of Darwin’s theory of evolution by natural selection through the initial Darwinian phase of the “Darwinian Revolution” up to the publication of the Descent of Man in 1871. The development of evolutionary ideas before Darwin’s work has been treated in the separate entry evolutionary thought before Darwin . Several additional aspects of Darwin’s theory of evolution and his biographical development are dealt with in other entries in this encyclopedia (see the entries on Darwinism ; species ; natural selection ; creationism ). The remainder of this entry will focus on aspects of Darwin’s theory not developed in the other entries. It will also maintain a historical and textual approach. Other entries in this encyclopedia cited at the end of the article and the bibliography should be consulted for discussions beyond this point. The issues will be examined under the following headings:

1.1 Historiographical Issues

1.2 darwin’s early reflections, 2.1. the concept of natural selection.

• 2.2. The Argument of the Published Origin

3.1 The Popular Reception of Darwin’s Theory

3.2 the professional reception of darwin’s theory, 4.1 the genesis of darwin’s descent, 4.2 darwin on mental powers, 4.3 the ethical theory of the descent of man.

• 4.4 The Reception of the Descent

5. Summary and Conclusion

Other internet resources, related entries, acknowledgments, 1. the origins of darwin’s theory.

Charles Darwin’s version of transformism has been the subject of massive historical and philosophical scholarship almost unparalleled in any other area of the history of science. This includes the continued flow of monographic studies and collections of articles on particular aspects of Darwin’s theory (Prestes 2023; R. J. Richards and Ruse 2016; Ruse 2013a, 2009a,b,c; Ruse and Richards 2009; Hodge and Radick 2009; Hösle and Illies 2005; Gayon 1998; Bowler 1996; Depew and Weber 1995; Kohn 1985a). The continuous production of popular and professional biographical studies on Darwin provides ever new insights (Ruse et al. 2013a; Johnson 2012; Desmond and Moore 1991, 2009; Browne 1995, 2002; Bowlby 1990; Bowler 1990). In addition, major editing projects on Darwin’s manuscripts and the completion of the Correspondence , project through the entirety of Darwin’s life, continue to reveal details and new insights into the issues surrounding Darwin’s own thought (Keynes [ed.] 2000; Burkhardt et al. [eds] 1985–2023; Barrett et al. [eds.] 1987). The Cambridge Darwin Online website (see Other Internet Resources ) serves as an international clearinghouse for this worldwide Darwinian scholarship, functioning as a repository for electronic versions of all the original works of Darwin, including manuscripts and related secondary materials. It also supplies a continuously updated guide to current literature.

A long tradition of scholarship has interpreted Darwin’s theory to have originated from a framework defined by endemic British natural history, a British tradition of natural theology defined particularly by William Paley (1743–1805), the methodological precepts of John Herschel (1792–1871), developed in his A Preliminary Discourse on the Study of Natural Philosophy (1830 [1987]), and the geological theories of Charles Lyell (1797–1875). His conversion to the uniformitarian geology of Charles Lyell and to Lyell’s advocacy of “deep” geological time during the voyage of the HMS Beagle (December 1831–October 1836), has been seen as fundamental in his formation (Norman 2013; Herbert 2005; Hodge 1983). Complementing this predominantly anglophone historiography has been the social-constructivist analyses emphasizing the origins of Darwin’s theories in British Political Economy (Young 1985: chps. 2, 4, 5). It has also been argued that a primary generating source of Darwin’s inquiries was his involvement with the British anti-slavery movement, a concern reaching back to his revulsion against slavery developed during the Beagle years (Desmond and Moore 2009).

A body of recent historiography, on the other hand, drawing on the wealth of manuscripts and correspondence that have become available since the 1960s (online at Darwin online “Papers and Manuscripts” section, see Other Internet Resources ) has de-emphasized some of the novelty of Darwin’s views and questions have been raised regarding the validity of the standard biographical picture of the early Darwin. These materials have drawn attention to previously ignored aspects of Darwin’s biography. In particular, the importance of his Edinburgh period from 1825–27, largely discounted in importance by Darwin himself in his late Autobiography , has been seen as critical for his subsequent development (Desmond and Moore 1991; Hodge 1985). As a young medical student at the University of Edinburgh (1825–27), Darwin developed a close relationship with the comparative anatomist Robert Edmond Grant (1793–1874) through the student Plinian Society, and in many respects Grant served as Darwin’s first mentor in science in the pre- Beagle years (Desmond and Moore 1991, chp. 1). Through Grant he was exposed to the transformist theories of Jean Baptiste Lamarck and the Cuvier-Geoffroy debate centered on the Paris Muséum nationale d’histoire naturelle (see entry on evolutionary thought before Darwin , Section 4).

These differing interpretive frameworks make investigations into the origins of Darwin’s theory an active area of historical research. The following section will explore these origins.

In its historical origins, Darwin’s theory was different in kind from its main predecessors in important ways (Ruse 2013b; Sloan 2009a; see also the entry on evolutionary thought before Darwin ). Viewed against a longer historical scenario, Darwin’s theory does not deal with cosmology or the origins of the world and life through naturalistic means, and therefore was more restricted in its theoretical scope than its main predecessors influenced by the reflections of Georges Louis LeClerc de Buffon (1707–1788), Johann Herder (1744–1803, and German Naturphilosophen inspired by Friederich Schelling (1775–1854) . This restriction also distinguished Darwin’s work from the grand evolutionary cosmology put forth anonymously in 1844 by the Scottish publisher Robert Chambers (1802–1871) in his immensely popular Vestiges of the Natural History of Creation , a work which in many respects prepared Victorian society in England, and pre-Civil War America for the acceptance of a general evolutionary theory in some form (Secord 2000; MacPherson 2015). It also distinguishes Darwin’s formulations from the theories of his contemporary Herbert Spencer (1820–1903).

Darwin’s theory first took written form in reflections in a series of notebooks begun during the latter part of the Beagle voyage and continued after the return of the Beagle to England in October of 1836 (Barrett et al., 1987). His reflections on the possibility of species change are first entered in March of 1837 (“Red Notebook”) and are developed in the other notebooks (B–E) through July of 1839 (Barrett et al. 1987; Hodge 2013a, 2009). Beginning with the reflections of the third or “D” “transmutation” Notebook, composed between July and October of 1838, Darwin first worked out the rudiments of what was to become his theory of natural selection. In the parallel “M” and “N” Notebooks, dating between July of 1838 and July of 1839, and in a loose collection called “Old and Useless Notes”, dating from approximately 1838–40, he also developed many of his main ideas on human evolution that would only be made public in the Descent of Man of 1871 (below, Section 4).

To summarize a complex issue, these Notebook reflections show Darwin proceeding through a series of stages in which he first formulated a general theory of the transformation of species by historical descent from common ancestors. He then attempted to work out a causal theory of life that would explain the tendency of life to complexify and diversify (Hodge 2013a, 2009, 1985; Sloan 1986). This causal inquiry into the underlying nature of life, and with it the search for an explanation of life’s innate tendency to develop and complexify, was then replaced by a dramatic shift in focus away from these inquiries. This concern with a causal theory of life was then replaced by a new emphasis on external forces controlling population, a thesis developed from his reading of Thomas Malthus’s (1766–1834) Essay on the Principle of Population (6th ed. 1826). For Malthus, human populaton was assumed to expand geometrically, while food supply expanded arithmetically, leading to an inevitable struggle of humans for existence. The impact of Darwin’s reading of this edition of the Essay in August of 1838, was dramatic. It enabled him to theorize the existence of a constantly-acting dynamic force behind the transformation of species.

Darwin’s innovation was to universalize the Malthusian “principle of population” to apply to all of nature. In so doing, Darwin effectively introduced what may be termed an “inertial” principle into his theory, although such language is never used in his text. Newton’s first law of motion, set forth in his Mathematical Principles of Natural Philosophy (1st ed. 1687), established his physical system upon the tendency of all material bodies to persist eternally either at rest or in uniform motion in a straight line, requiring a causal force explanation for any deviations from this initial state. But Newton did not seek a deeper metaphysical explanation of this inertial state. Law One is simply an “axiom” in Newton’s Principia. Similarly, the principle of population supplied Darwin with the assumption of an initial dynamic state of affairs that was not itself explained within the theory—there is no attempt to account causally for this tendency of living beings universally to reproduce geometrically. Similarly for Darwin, the principle of population functions axiomatically, defining a set of initial conditions from which any deviance from this ideal state demands explanation.

This theoretical shift enabled Darwin to bracket his earlier efforts to develop a causal theory of life, and focus instead on the means by which the dynamic force of population was controlled. This allowed him to emphasize how controls on population worked in company with the phenomenon of slight individual variation between members of the same species, in company with changing conditions of life, to produce a gradual change of form and function over time, leading to new varieties and eventually to new species. This opened up the framework for Darwin’s most important innovation, the concept of “natural” selection.

2. Darwinian Evolution

The primary distinguishing feature of Darwin’s theory that separates it from previous explanations of species change centers on the causal explanation he offered for how this process occurred. Prior theories, such as the theory of Jean-Baptiste Lamarck (see entry on evolutionary thought before Darwin ), relied on the inherent dynamic properties of matter. The change of species was not, in these pre-Darwinian efforts, explained through an adaptive process. Darwin’s emphasis after the composition of Notebook D on the factors controlling population increase, rather than on a dynamic theory of life grounded in vital forces, accounts for many of the differences between Darwin’s theory and those of his predecessors and contemporaries.

These differences can be summarized in the concept of natural selection as the central theoretical component of Darwinian theory. However, the exact meaning of this concept, and the varying ways he stated the principle in the Origin over its six editions (1859–1872), has given rise to multiple interpretations of the meaning of this principle in the history of Darwinism, and the different understandings of his meaning deeply affected different national and cultural receptions of his theory (see below, Section 3 .1).

One way to see the complexity of Darwin’s own thinking on these issues is to follow the textual development of this concept from the close of the Notebook period (1839) to the publication of the Origin of Species in 1859. This period of approximately twenty years involved Darwin in a series of reflections that form successive strata in the final version of his theory of the evolution of species. Understanding the historical sequence of these developments also has significance for subsequent controversies over this concept and the different readings of the Origin as it went through its successive revisions. This historical development of the concept also has some bearing on assessing Darwin’s relevance for more general philosophical questions, such as those surrounding the relevance of his theory for such issues as the concept of a more general teleology of nature.

The earliest set of themes in the manuscript elaboration of natural selection theory can be characterized as those developed through a particular form of the argument from analogy. This took the form of a strong “proportional” form of the analogical argument that equated the relation of human selection to the development of domestic breeds as an argument of the basic form: human selection is to domestic variety formation as natural selection is to natural species formation (White, Hodge and Radick 2021, chps. 4–5). This makes a direct analogy between the actions of nature with those of humans in the process of selection. The specific expressions, and changes, in this analogy are important to follow closely. As this was expressed in the first coherent draft of the theory, a 39-page pencil manuscript written in 1842, this discussion analogized the concept of selection of forms by human agency in the creation of the varieties of domestic animals and plants, to the active selection in the natural world by an almost conscious agency, a “being infinitely more sagacious than man (not an omniscient creator)” who acts over “thousands and thousands of years” on “all the variations which tended towards certain ends” (Darwin 1842 in Glick and Kohn 1996, 91). This agency selects out those features most beneficial to organisms in relation to conditions of life, analogous in its action to the selection by man on domestic forms in the production of different breeds. Interwoven with these references to an almost Platonic demiurge are appeals to the selecting power of an active “Nature”:

Nature’s variation far less, but such selection far more rigid and scrutinizing […] Nature lets <<an>> animal live, till on actual proof it is found less able to do the required work to serve the desired end, man judges solely by his eye, and knows not whether nerves, muscles, arteries, are developed in proportion to the change of external form. (Ibid., 93)

These themes were continued in the 230 page draft of his theory of 1844. Again he referred to the selective action of a wise “Being with penetration sufficient to perceive differences in the outer and innermost organization quite imperceptible to man, and with forethought extending over future centuries to watch with unerring care and select for any object the offspring of an organism produced” (Darwin 1844 in ibid., 101). This selection was made with greater foresight and wisdom than human selection. As he envisions the working of this causal agency,

In accordance with the plan by which this universe seems governed by the Creator, let us consider whether there exist any secondary means in the economy of nature by which the process of selection could go on adapting, nicely and wonderfully, organisms, if in ever so small a degree plastic, to diverse ends. I believe such secondary means do exist. (Ibid., 103).

Darwin returned to these issues in 1856, following a twelve-year period in which he published his Geological Observations on the Volcanic Islands (1844), the second edition of his Journal of Researches (1845), Geological Observations on South America (1846), the four volumes on fossil and living barnacles ( Cirripedia ) (1851, 54, 55), and Geological Observations on Coral Reefs (1851). In addition, he published several smaller papers on invertebrate zoology and on geology, and reported on his experiments on the resistance of seeds to salt water, a topic that would be of importance in his explanation of the population of remote islands.

These intervening inquiries positioned Darwin to deal with the question of species permanence against an extensive empirical background. The initial major synthesis of these investigations takes place in his long manuscript, or “Big Species Book”, commenced in 1856, known in current scholarship as the “Natural Selection” manuscript. This formed the immediate background text behind the published Origin . Although incomplete, the “Natural Selection” manuscript provides insights into many critical issues in Darwin’s thinking. It was also prepared with an eye to the scholarly community. This distinguishes its content and presentation from that of the subsequent “abstract” which became the published Origin of Species . “Natural Selection” contained tables of data, references to scholarly literature, and other apparatus expected of a non-popular work, none of which appeared in the published Origin .

The “Natural Selection” manuscript also contained some new theoretical developments of relevance to the concept of natural selection that are not found in earlier manuscripts. Scholars have noted the introduction in this manuscript of the “principle of divergence”, the thesis that organisms under the action of natural selection will tend to radiate and diversify within their “conditions of life”—the contemporary name for the complex of environmental and species-interaction relationships (Kohn 1985b, 2009). Although the concept of group divergence under the action of natural selection might be seen as an implication of Darwin’s theory from his earliest formulations of the 1830s, nonetheless Darwin’s explicit definition of this as a “principle”, and its discussion in a long late insertion in the “Natural Selection” manuscript, suggests its importance for Darwin’s mature theory. The principle of divergence was now seen by Darwin to form an important link between natural variation and the conditions of existence under the action of the driving force of population increase.

Still evident in the “Natural Selection” manuscript is Darwin’s implicit appeal to some kind of teleological ordering of the process. The action of the masculine-gendered “wise being” of the earlier manuscripts, however, has now been given over entirely to the action of a selective “Nature”, now referred to in the traditional feminine gender. This Nature,

…cares not for mere external appearance; she may be said to scrutinise with a severe eye, every nerve, vessel & muscle; every habit, instinct, shade of constitution,—the whole machinery of the organisation. There will be here no caprice, no favouring: the good will be preserved & the bad rigidly destroyed.… Can we wonder then, that nature’s productions bear the stamp of a far higher perfection than man’s product by artificial selection. With nature the most gradual, steady, unerring, deep-sighted selection,—perfect adaption [sic] to the conditions of existence.… (Darwin 1856–58 [1974: 224–225])

The language of this passage, directly underlying statements about the action of “natural selection” in the first edition of the published Origin , indicates the complexity in the exegesis of Darwin’s meaning of “natural selection” when viewed in light of its historical genesis (Ospovat 1981). The parallels between art and nature, the intentionality implied in the term “selection”, the notion of “perfect” adaptation, and the substantive conception of “nature” as an agency working toward certain ends, all render Darwin’s views on teleological purpose more complex than they are typically interpreted from the standpoint of contemporary Neo-selectionist theory (Lennox 1993, 2013). As will be discussed below, the changes Darwin subsequently made in his formulations of this concept over the history of the Origin have led to different conceptions of what he meant by this principle.

The hurried preparation and publication of the Origin between the summer of 1858 and November of 1859 was prompted by the receipt on June 18 of 1858 of a letter and manuscript from Alfred Russel Wallace (1823–1913) that outlined his remarkably similar views on the possibility of continuous species change under the action of a selection upon natural variation (Wallace 1858 in Glick and Kohn 1996, 337–45). This event had important implications for the subsequent form of Darwin’s published argument. Rapidly condensing the detailed arguments of the unfinished “Natural Selection” manuscript into shorter chapters, Darwin also universalized several claims that he had only developed with reference to specific groups of organisms, or which he had applied only to more limited situations in the manuscript. This resulted in a presentation of his theory at the level of broad generalization. The absence of tables of data, detailed footnotes, and references to the secondary literature in the published version also resulted in predictable criticisms which will be discussed below in Section 3.2 .

2.2. The Central Argument of the Published Origin

The Origin of Species by Means of Natural Selection, or the Preservaton of Favoured Races in the Struggle for Life was issued in London by the publishing house of John Murray on November 24, 1859 (Darwin 1859 [1964]). The structure of the argument presented in the published Origin has been the topic of considerable literature and can only be summarized here. Although Darwin himself described his book as “one long argument”, the exact nature of this argument is not immediately transparent, and alternative interpretations have been made of his reasoning and rhetorical strategies in formulating his evolutionary theory. (Prestes 2023; White, Hodge and Radick 2021; Hodge 2013b, 1977; Hoquet 2013; Hull 2009; Waters 2009; Depew 2009; Ruse 2009; Lennox 2005; Hodge 1983b).

The scholarly reconstruction of Darwin’s methodology employed in the Origin has taken two primary forms. One approach has been to reconstruct it from the standpoint of currently accepted models of scientific explanation, sometimes presenting it as a formal deductive model (Sober 1984). Another, more historical, approach interprets his methodology in the context of accepted canons of scientific explanation found in Victorian discussions of the period (see the entry on Darwinism ; Prestes 2023; White, Hodge and Radick 2021; Hodge 2013b, 1983b, 1977; Hoquet 2013; Hull 2009; Waters 2009; Depew 2009; Lennox 2005). The degree to which Darwin did in fact draw from the available methodological discussions of his contemporaries—John Herschel, William Whewell, John Stuart Mill—is not fully clear from available documentary sources. The claim most readily documented, and defended particularly by White, Hodge and Radick (2021) and M. J. S. Hodge (1977, 1983a), has emphasized the importance of John Herschel’s A Preliminary Discourse on the Study of Natural Philosophy (1830 [1987]), which Darwin read as a young student at Cambridge prior to his departure on the HMS Beagle in December of 1831.

In Herschel’s text he would have encountered the claim that science seeks to determine “true causes”— vera causae— of phenomena through the satisfaction of explicit criteria of adequacy (Herschel, 1830 [1987], chp. 6). This concept Newton had specified in the Principia as the third of his “Rules of Reasoning in Philosophy” (see the entry on Newton’s philosophy , Section 4). Elucidation of such causes was to be the goal of scientific explanation. Vera causae , in Herschel’s formulation, were those necessary to produce the given effects; they were truly active in producing the effects; and they adequately explained these effects.

The other plausible methodological source for Darwin’s mature reasoning was the work of his older contemporary and former Cambridge mentor, the Rev. William Whewell (1794–1866), whose three-volume History of the Inductive Sciences (Whewell 1837) Darwin read with care after his return from his round-the-world voyage (Ruse 2013c, 1975). On this reading, a plausible argument has been made that the actual structure of Darwin’s text is more closely similar to a “Whewellian” model of argument. In Whewell’s accounts of his philosophy of scientific methodology (Whewell 1840, 1858), the emphasis of scientific inquiry is, as Herschel had also argued, to be placed on the discovery of “true causes”. But evidence for the determination of a vera causa was to be demonstrated by the ability of disparate phenomena to be drawn together under a single unifying “Conception of the Mind”, exemplified for Whewell by Newton’s universal law of gravitation. This “Consilience of Inductions”, as Whewell termed this process of theoretical unification under a few simple concepts, was achieved only by true scientific theories employing true causes (Whewell 1840: xxxix). It has therefore been argued that Darwin’s theory fundamentally produces this kind of consilience argument, and that his methodology is more properly aligned with that of Whewell.

A third account, related to the Whewellian reading, is that of David Depew. Building on Darwin’s claim that he was addressing “the general naturalist public,” Darwin is seen as developing what Depew has designated as “situated argumentation”, similar to the views developed by contemporary Oxford logician and rhetorical theorist Richard Whately (1787–1863) (Depew 2009). This rhetorical strategy proceeds by drawing the reader into Darwin’s world by personal narration as it presents a series of limited issues for acceptance in the first three chapters, none of which required of the reader a considerable leap of theoretical assent, and most of which, such as natural variation and Malthusian population increase, had already been recognized in some form in the literature of the period.

As Darwin presented his arguments to the public, he opens with a pair of chapters that draw upon the strong analogy developed in the manuscripts between the action of human art in the production of domestic forms, and the actions of selection “by nature.” The resultant forms are presumed to have arisen through the action of human selection on the slight variations existing between individuals within the same species. The interpretation of this process as implying directional, and even intentional, selection by a providential “Nature” that we have seen in the manuscripts was, however, downplayed in the published work through the importance given by Darwin to the role of “unconscious” selection, a concept not encountered in the Natural Selection manuscript. Such selection denotes the practice even carried out by aboriginal peoples who simply seek to maintain the integrity and survival of a breed or species by preserving the “best” forms.

The domestic breeding analogy is, however, more than a decorative rhetorical strategy. It repeatedly functions for Darwin as the principal empirical example to which he could appeal at several places in the text as a means of visualizing the working of natural selection in nature, and this appeal remains intact through the six editions of the Origin.

From this model of human selection working on small individual natural variations to produce the domestic forms, Darwin then developed in the second chapter the implications of “natural” variation, delaying discussion of the concept of natural selection until Chapter IV. The focus of the second chapter introduces another important issue. Here he extends the discussion of variation developed in Chapter I into a critical analysis of the common understanding of classification as grounded on the definition of species and higher groups based on the possession of essential defining properties. It is in this chapter that Darwin most explicitly develops his own position on the nature of organic species in relation to his theory of descent. It is also in this chapter that he sets forth the ingredients for his attack on one meaning of species “essentialism”.

Darwin’s analysis of the “species question” involves a complex argument that has many implications for how his work was read by his contemporaries and successors, and its interpretation has generated a considerable literature (see the entries on species and Darwinism ; Mallet 2013; R. A. Richards 2010; Wilkins 2009; Stamos 2007; Sloan 2009b, 2013; Beatty 1985).

Prior tradition had been heavily affected by eighteenth-century French naturalist Buffon’s novel conception of organic species in which he made a sharp distinction between “natural” species, defined primarily by fertile interbreeding, and “artificial” species and varieties defined by morphological traits and measurements upon these (see the entry on evolutionary thought before Darwin , Section 3.3). This distinction was utilized selectively by Darwin in an unusual blending of two traditions of discussion that are conflated in creative ways in Darwin’s analysis.

Particularly as the conception of species had been discussed by German natural historians of the early nineteenth-century affected by distinctions introduced by philosopher Immanuel Kant (1724–1804), “Buffonian” species were defined by the material unity of common descent and reproductive continuity. This distinguished them by their historical and material character from the taxonomic species of the “Linnean” tradition of natural history. This distinction between “natural” and “logical” species had maintained a distinction between problems presented in the practical classification of preserved specimens, distinguished by external characters, and those relating to the unity of natural species, which was grounded upon reproductive unity and the sterility criterion (Sloan 2009b).

Remarkable in Darwin’s argument is the way in which he draws selectively in his readings from these two preexistent traditions to undermine the different grounds of species “realism” assumed within both of these traditions of discourse. One framework—what can be considered in his immediate context the “Linnean” tradition—regarded species in the sense of universals of logic or class concepts, whose “reality” was often grounded on the concept of divine creation. The alternative “Buffonian” tradition viewed species more naturalistically as material lineages of descent whose continuity was determined by some kind of immanent principle, such as the possession of a conserving “internal mold” or specifying vital force (see evolutionary thought before Darwin 3.3). The result in Darwin’s hands is a complex terminological interweaving of concepts of Variety, Race, Sub-species, Tribe, and Family that can be shown to be a fusion of different traditions of discussion in the literature of the period. This creative conflation also led to many confusions among his contemporaries about how Darwin actually did conceive of species and species change in time.

Darwin addresses the species question by raising the problems caused by natural variation in the practical discrimination of taxa at the species and varietal levels, an issue with which he had become closely familiar in his taxonomic revision of the Sub-class Cirripedia (barnacles) in his eight-year study on this group. Although the difficulty of taxonomic distinctions at this level was a well-recognized problem in the literature of the time, Darwin subtly transforms this practical problem into a metaphysical ambiguity—the fuzziness of formal taxonomic distinctions created by variation in preserved specimens is seen to imply a similar ambiguity of “natural” species boundaries.

We follow this in reading how natural variation is employed by Darwin in Chapter Two of the Origin to break down the distinction between species and varieties as these concepts were commonly employed in the practical taxonomic literature. The arbitrariness apparent in making distinctions, particularly in plants and invertebrates, meant that such species were only what “naturalists having sound judgment and wide experience” defined them to be ( Origin 1859 [1964], 47). These arguments form the basis for claims by his contemporaries that Darwin was a species “nominalist”, who defined species only as conventional and convenient divisions of a continuum of individuals.

But this feature of Darwin’s discussion of species captures only in part the complexity of his argument. Drawing also on the tradition of species realism developed within the “Buffonian” tradition, Darwin also affirmed that species and varieties are defined by common descent and material relations of interbreeding. Darwin then employed the ambiguity of the distinction between species and varieties created by individual variation in practical taxonomy to undermine the ontological fixity of “natural” species. Varieties are not simply the formal taxonomic subdivisions of a natural species as conceived in the Linnaean tradition. They are, as he terms them, “incipient” species (ibid., 52). This subtly transformed the issue of local variation and adaptation to circumstances into a primary ingredient for historical evolutionary change. The full implications to be drawn from this argument were, however, only to be revealed in Chapter Four of the text.

Before assembling the ingredients of these first two chapters, Darwin then introduced in Chapter Three the concept of a “struggle for existence”. This concept is introduced in a “large and metaphorical sense” that included different levels of organic interactions, from direct struggle for food and space to the struggle for life of a plant in a desert. Although described as an application of Thomas Malthus’s parameter of geometrical increase of population in relation to the arithmetical increase of food supply, Darwin’s use of this concept in fact reinterprets Malthus’s principle, which was formulated only with reference to human population in relation to food supply. It now becomes a general principle governing all of organic life. Thus all organisms, including those comprising food for others, would be governed by the tendency to geometrical increase.

Through this universalization, the controls on population become only in the extreme case grounded directly on the traditional Malthusian limitations of food and space. Normal controls are instead exerted through a complex network of relationships of species acting one on another in predator-prey, parasite-host, and food-web relations. This profound revision of Malthus’s arguments rendered Darwin’s theory deeply “ecological” as this term would later be employed. We can cite two thought experiments employed by Darwin himself as illustrations (ibid., 72–74). The first concerns the explanation of the abundance of red clover in England. This Darwin sees as dependent on the numbers of pollinating humble bees, which are controlled in turn by the number of mice, and these are controlled by the number of cats, making cats the remote determinants of clover abundance. The second instance concerns the explanation of the abundance of Scotch Fir. In this example, the number of fir trees is limited indirectly by the number of cattle.

With the ingredients of the first three chapters in place, Darwin was positioned to assemble these together in his grand synthesis of Chapter Four on “natural” selection. In this long discussion, Darwin develops the main exposition of his central theoretical concept. For his contemporaries and for the subsequent tradition, however, the meaning of Darwin’s concept of “natural” selection was not unambiguously evident for reasons we have outlined above, and these unclarities were to be the source of several persistent lines of disagreement and controversy.

The complexities in Darwin’s presentation of his central principle over the six editions of the published Origin served historically to generate several different readings of his text. In the initial introduction of the principle of natural selection in the first edition of Darwin’s text, it is characterized as “preservation of favourable variations and the rejection of injurious variations” (ibid., 81). When Darwin elaborated on this concept in Chapter Four of the first edition, he continued to describe natural selection in language suggesting that it involved intentional selection, continuing the strong art-nature analogy found in the manuscripts. For example:

As man can produce and certainly has produced a great result by his methodical and unconscious means of selection, what may not nature effect? Man can act only on external and visible characters: nature cares nothing for appearances, except in so far as they may be useful to any being. She can act on every internal organ, on every shade of constitutional difference, on the whole machinery of life. Man selects only for his own good; Nature only for that of the being which she tends. Every selected character is fully exercised by her; and the being is placed under well-suited conditions of life. (Ibid., 83)

The manuscript history behind such passages prevents the simple discounting of these statements as mere rhetorical imagery. As we have seen, the parallel between intentional human selectivity and that of “nature” formed the proportional analogical model upon which the concept of natural selection was originally constructed.

Criticisms that quickly developed over the overt intentionality embedded in such passages, however, led Darwin to revise the argument in editions beginning with the third edition of 1861. From this point onward he explicitly downplayed the intentional and teleological language of the first two editions, denying that his appeals to the selective role of “nature” were anything more than a literary figure. Darwin then moved decisively in the direction of defining natural selection as the description of the action of natural laws working upon organisms rather than as an efficient or final cause of life. He also regrets in his Correspondence his mistake in not utilizing the designation “natural preservation” rather than “natural selection” to characterize his principle (letter to Lyell 28 September 1860, Burkhardt Correspondence 8, 397; also see Darwin Correspondence Project in Other Internet Resources ). In response to criticisms of Alfred Russel Wallace, Darwin then adopted in the fifth edition of 1869 his contemporary (1820–1903) Herbert Spencer’s designator, “survival of the fittest”, as a synonym for “natural selection” (Spencer 1864, 444–45; Darwin 1869, 72). This redefinition further shifted the meaning of natural selection away from the concept that can be extracted from the early texts and drafts. These final statements of the late 1860s and early 70s underlie the tradition of later “mechanistic” and non-teleological understandings of natural selection, a reading developed by his disciples who, in the words of David Depew, “had little use for either his natural theodicy or his image of a benignly scrutinizing selection” (Depew 2009, 253). The degree to which this change preserved the original strong analogy between art and nature can, however, be questioned. Critics of the use of this analogy had argued since the original formulations that the comparison of the two modes of selection actually worked against Darwin’s theory (Wallace 1858 in Glick and Kohn 1997, 343). This critique would also be leveled against Darwin in the critical review of 1867 by Henry Fleeming Jenkin discussed below.

The conceptual synthesis of Chapter Four also introduced discussions of such matters as the conditions under which natural selection most optimally worked, the role of isolation, the causes of the extinction of species, and the principle of divergence. Many of these points were made through the imaginative use of “thought experiments” in which Darwin constructed possible scenarios through which natural selection could bring about substantial change.

One prominent way Darwin captured for the reader the complexity of this process is reflected in the single diagram to appear in all the editions of the Origin . In this illustration, originally located as an Appendix to the first edition, but thereafter moved into Chapter Four, Darwin summarized his conception of how species were formed and diverged from common ancestral points. This image also served to depict the frequent extinction of most lineages, an issue developed in detail in Chapter Ten. It displayed pictorially the principle of divergence, illustrating the general tendency of populations to diverge and fragment under the pressure of population increase. It supplied a way of envisioning relations of taxonomic affinity to time, and illstrated the persistence of some forms unchanged over long geological periods in which stable conditions prevail.

Figure: Tree of life diagram from Origin of Species ( Origin 1859:“Appendix”.

Remarkable about Darwin’s diagram of the tree of life is the relativity of its coordinates. It is first presented as applying only to the divergences taking place in taxa at the species level, with varieties represented by the small lower-case letters within species A–L of a “wide ranging genus”, with the horizontal lines representing time segments measured in terms of a limited number of generations. However, the attentive reader could quickly see that Darwin’s destructive analysis of the distinction between “natural” and “artificial” species in Chapter Two, implied the relativity of the species-variety distinction, this diagram could represent eventually all organic relationships, from those at the non-controversial level of diverging varieties within fixed species, to those of the relations of Species within different genera. Letters A–L could also represent taxa at the level of genera, families or orders. The diagram can thus be applied to relationships between all levels of the Linnaean hierarchy with the time segments representing potentially vast expanses of time, and the horizontal spread of branches the degree of taxonomic divergence over time. In a very few pages of argument, the diagram was generalized to represent the most extensive group relations, encompassing the whole of geological time. Extension of the dotted lines at the bottom could even suggest, as Darwin argues in the last paragraph of the Origin , that all life was a result of “several powers, having been originally breathed into a few forms or into one” (Darwin 1859 [1964], 490). This could suggest a single naturalistic origin of all original forms either by material emergence, or through the action of a vitalistic power of life. Darwin’s use of Biblical language could also be read as allowing for the action of a supernatural cause.

In response to criticisms concerning this latter point, Darwin quickly added to the final paragraph in the second edition of 1860 the phrase “by the Creator” (1860: 484), which remained in all subsequent editions. as did the quotations on the frontispiece from familiar discussions in British natural theology concerning creation by secondary causation. Conceptual space was thereby created for the reading of the Origin by some contemporaries, notably by the Harvard botanist Asa Gray (1810–88), as compatible with traditional natural theology (Gray 1860).

The sweep of the theoretical generalization that closed the natural selection chapter, one restated even more generally in the final paragraph of the book, required Darwin to deal with several obvious objections to the theory that constitute the main “defensive” chapters of the Origin (Five–Nine), and occupy him through the numerous revisions of the text between 1859 and 1872. As suggested by David Depew, the rhetorical structure of the original text developed in an almost “objections and response” structure that resulted in a constant stream of revisions to various editions of the original text as Darwin engaged his opponents (Depew 2009; Peckham 2006). Anticipating at first publication several obvious lines of objection, Darwin devoted much of the text of the original Origin to offering a solution in advance to predictable difficulties. As Darwin outlined these main lines of objection, he discussed, first, the apparent absence of numerous slight gradations between species, both in the present and in the fossil record, of the kind that would seem to be predictable from the gradualist workings of the theory (Chps. Six, Nine). Second, the gradual development of organs and structures of extreme complexity, such as the vertebrate eye, an organ which had since Antiquity served as a mainstay of the argument for external teleological design (Chp. Six). Third, the evolution of the elaborate instincts of animals and the puzzling problem of the evolution of social insects that developed sterile neuter castes, proved to be a particularly difficult issue for Darwin in the manuscript phase of his work and needed some account (Chp. Seven). As a fourth major issue needing attention, the traditional distinction between natural species defined by interfertility, and artificial species defined by morphological differences, required an additional chapter of analysis in which he sought to undermine the absolute character of the interbreeding criterion as a sign of fixed natural species (Chp. Eight).

In Chapter Ten, Darwin developed his interpretation of the fossil record. At issue was the claim by Lamarckian and other transformists, as well as Cuvierian catastrophists such as William Buckland (1784–1856) (see the entry on evolutionary thought before Darwin , Section 4.1), that the fossil record displayed a historical sequence beginning with simpler plants and animals, arriving either by transformism or replacement, at the appearance of more complex forms in geological history. Opposition to this thesis of “geological progressionism” had been made by none other than Darwin’s great mentor in geology, Charles Lyell in his Principles of Geology (Lyell 1832 [1990], vol. 2, chp. xi; Desmond 1984; Bowler 1976). Darwin defended the progressionist view against Lyell’s arguments in this chapter.

To each of the lines of objection to his theory, Darwin offered his contemporaries plausible replies. Additional arguments were worked out through the insertion of numerous textual insertions over the five revisions of the Origin between 1860 and 1872, including the addition of a new chapter to the sixth edition dealing with “miscellaneous” objections, responding primarily to the criticisms of St. George Jackson Mivart (1827–1900) developed in his Genesis of Species (Mivart 1871).

For reasons related both to the condensed and summary form of public presentation, and also as a reflection of the bold conceptual sweep of the theory, the primary argument of the Origin could not gain its force from the data presented by the book itself. Instead, it presented an argument from unifying simplicity, gaining its force and achieving assent from the ability of Darwin’s theory to draw together in its final synthesizing chapters (Ten–Thirteen) a wide variety of issues in taxonomy, comparative anatomy, paleontology, biogeography, and embryology under the simple principles worked out in the first four chapters. This “consilience” argument might be seen as the best reflection of the impact of William Whewell’s methodology (see above).

As Darwin envisioned the issue, with the acceptance of his theory, “a grand untrodden field of inquiry will be opened” in natural history. The long-standing issues of species origins, if not the the explanation of the ultimate origins of life, as well as the causes of their extinction, had been brought within the domain of naturalistic explanation. It is in this context that he makes the sole reference in the text to the claim that “light will be thrown on the origin of man and his history”. And in a statement that will foreshadow the important issues of the Descent of Man of 1871, he speaks of how “Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation” (ibid., 488)

3. The Reception of the Origin

The broad sweep of Darwin’s claims, the brevity of the empirical evidence actually supplied in the Origin , and the implications of his theory for several more general philosophical and theological issues, opened up a controversy over Darwinian evolution that has waxed and waned over more than 160 years. The theory was inserted into a complex set of different national and cultural receptions the study of which currently forms a scholarly industry in its own right. European, Latin American and Anglophone receptions have been most deeply studied (Bowler 2013a; Gayon 2013; Largent 2013; Glick 1988, 2013; Glick and Shaffer 2014; Engels and Glick 2008; Gliboff 2008; Numbers 1998; Pancaldi, 1991; Todes 1989; Kelly 1981; Hull 1973; Mullen 1964). To these have been added analyses of non-Western recptions (Jin 2020, 2019 a,b; Yang 2013; Shen 2016; Elshakry 2013; Pusey 1983). These analyses display common patterns in both Western and non-Western readings of Darwin’s theory, in which these receptions were conditioned, if not determined, by the pre-existing intellectual, scientific, religious, social, and political contexts into which his works were inserted.

In the anglophone world, Darwin’s theory fell into a complex social environment that in the United States meant into the pre-Civil War slavery debates (Largent 2013; Numbers 1998). In the United Kingdom it was issued against the massive industrial expansion of mid-Victorian society, and the development of professionalized science. To restrict focus to aspects of the British reading public context, the pre-existing popularity of the anonymous Vestiges of the Natural History of Creation of 1844, which had reached 11 editions and sold 23,350 copies by December of 1860 (Secord “Introduction” to Chambers 1844 [1994], xxvii]), with more editions to appear by the end of the century, certainly prepared the groundwork for the general notion of the evolutionary origins of species by the working of secondary natural laws. The Vestiges ’s grand schema of a teleological development of life, from the earliest beginnings of the solar system in a gaseous nebula to the emergence of humanity under the action of a great “law of development”, had also been popularized for Victorian readers by Alfred Lord Tennyson’s epic poem In Memoriam (1850). This Vestiges backdrop provided a context in which some could read Darwin as supplying additional support for the belief in an optimistic historical development of life under teleological guidance of secondary laws with the promise of ultimate historical redemption. Such readings also rendered the Origin seemingly compatible with the progressive evolutionism of Darwin’s contemporary Herbert Spencer (see the entry on Herbert Spencer ). Because of these similarities, Spencer’s writings served as an important vehicle by which Darwin’s views, modified to fit the progressivist views expounded by Spencer, were first introduced in non-Western contexts (Jin 2020, 2019 a,b; Lightman [ed.] 2015; Pusey 1983). Such popular receptions ignored or revised Darwin’s concept of evolution by natural selection to fit these progressivist alternatives.

Outside the United Kingdom, the receptions of Darwin’s work display the importance of local context and pre-existent intellectual and social conditions. Three examples—France, Germany, and China—can be elaborated upon. In France, Darwin’s theory was received against the background of the prior debates over transformism of the 1830s that pitted the theories of Lamarck and Etienne Geoffroy St. Hilaire against Cuvier (Gayon 2013; entry on evolutionary thought before Darwin , 4.1). At least within official French Academic science, these debates had been resolved generally in favor of Cuvier’s anti-transformism. The intellectual framework provided by the “positive philosophy” of Auguste Comte (1798–1857) also worked both for and against Darwin. On one hand, Comte’s emphasis on the historical progress of science over superstition and metaphysics allowed Darwin to be summoned in support of a theory of the progress of science. The Origin was so interpreted in the preface to the first French translation of the Origin made by Clémence Royer (Harvey 2008). On the other hand, the Comtean three stages view of history, with its claim of the historical transcendence of speculative and metaphysical periods of science by a final period of experimental science governed by determinate laws, placed Darwinism in a metaphysical phase of speculative nature philosophy. This view is captured by the assessment of the leading physiologist and methodologist of French Science, Claude Bernard (1813–78). As he stated this in his 1865 treatise on scientific methodology, Darwin’s theory was to be regarded with those of “a Goethe, an Oken, a Carus, a Geoffroy Saint Hilaire”, locating it within speculative philosophy of nature rather than granting it the status of “positive” science (Bernard 1865 [1957], 91–92]).

In the Germanies, Darwin’s work entered a complex social, intellectual and political situation in the wake of the failed efforts to establish a liberal democracy in 1848. It also entered an intellectual culture strongly influenced by the pre-existent philosophical traditions of Kant, Schelling’s Naturphilosophie , German Romanticism, and the Idealism of Fichte and Hegel (R. J. Richards 2002, 2008, 2013; Gliboff 2007, 2008; Mullen 1964). These factors formed a complex political and philosophical environment into which Darwin’s developmental view of nature and theory of the transformation of species was quickly assimilated, if also altered. Many readings of Darwin consequently interpreted his arguments against the background of Schelling’s philosophy of nature. The marshalling of Darwin’s authority in debates over scientific materialism were also brought to the fore by the enthusiastic advocacy of Darwinism in Germany by University of Jena professor of zoology Ernst Heinrich Haeckel (1834–1919). More than any other individual, Haeckel made Darwinismus a major player in the polarized political and religious disputes of Bismarckian Germany (R. J. Richards 2008). Through his polemical writings, such as the Natural History of Creation (1868), Anthropogeny (1874), and Riddle of the Universe (1895–99), Haeckel advocated a materialist monism in the name of Darwin, and used this as a stick with which to beat traditional religion. Much of the historical conflict between religious communities and evolutionary biology can be traced back to Haeckel’s polemical writings, which went through numerous editions and translations, including several English and American editions that appeared into the early decades of the twentieth century.

To turn to a very different context, that of China, Darwin’s works entered Chinese discussions by a curious route. The initial discussions of Darwinian theory were generated by the translation of Thomas Henry Huxley’s 1893 Romanes Lecture “Evolution and Ethics” by the naval science scholar Yan Fu (1854–1921), who had encountered Darwinism while being educated at the Royal Naval College in Greenwich from 1877 to 1879. This translation of Huxley’s lecture, published in 1898 under the name of Tianyan Lun , was accompanied with an extensive commentary by Yan Fu that drew heavily upon the writings of Herbert Spencer which Yan Fu placed in opposition to the arguments of Huxley. This work has been shown to have been the main vehicle by which the Chinese learned indirectly of Darwin’s theory (Jin 2020, 2019 a, b; Yang 2013; Pusey 1983). In the interpretation of Yan Fu and his allies, such as Kan Yuwei (1858–1927), Darwinism was given a progressivist interpretation in line with aspects of Confucianism.

Beginning in 1902, a second phase of Darwinian reception began with a partial translation of the first five chapters of the sixth edition of the Origin by the Chinese scientist, trained in chemistry and metallurgy in Japan and Germany, Ma Junwu (1881–1940). This partial translation, published between 1902 and 1906, again modified the text itself to agree with the progressive evolutionism of Spencer and with the progressivism already encountered in Yan Fu’s popular Tianyan Lun. Only in September of 1920 did the Chinese have Ma Junwu’s full translation of Darwin’s sixth edition. This late translation presented a more faithful rendering of Darwin’s text, including an accurate translation of Darwin’s final views on natural selection (Jin 2019 a, b). As a political reformer and close associate of democratic reformer Sun Yat-Sen (1866–1925), Ma Junwu’s interest in translating Darwin was also was involved with his interest in revolutionary Chinese politics (Jin 2019a, 2022).

The reception of the Origin by those who held positions of professional research and teaching positions in universities, leadership positions in scientific societies, and employment in museums, was complex. These individuals were typically familiar with the empirical evidence and the technical scientific issues under debate in the 1860s in geology, comparative anatomy, embryology, biogeography, and classification theory. This group can usually be distinguished from lay interpreters who may not have made distinctions between the views of Lamarck, Chambers, Schelling, Spencer, and Darwin on the historical development of life.

If we concentrate attention on the reception by these professionals, Darwin’s work received varied endorsement (Hull 1973). Many prominent members of Darwin’s immediate intellectual circle—Adam Sedgwick, William Whewell, Charles Lyell, Richard Owen, and Thomas Huxley—had previously been highly critical of Chambers’s Vestiges in the 1840s for its speculative character and its scientific incompetence (Secord 2000). Darwin himself feared a similar reception, and he recognized the substantial challenge facing him in convincing this group and the larger community of scientific specialists with which he interacted and corresponded widely. With this group he was only partially successful.

Historical studies have revealed that only rarely did members of the scientific elites accept and develop Darwin’s theories exactly as they were presented in his texts. Statistical studies on the reception by the scientific community in England in the first decade after the publication of the Origin have shown a complicated picture in which there was neither wide-spread conversion of the scientific community to Darwin’s views, nor a clear generational stratification between younger converts and older resisters, counter to Darwin’s own predictions in the final chapter of the Origin (Hull et al. 1978). These studies also reveal a distinct willingness within the scientific community to separate acceptance of Darwin’s more general claim of species descent with modification from common ancestors from the endorsement of his explanation of this descent through the action of natural selection on slight morphological variations.

Of central importance in analyzing this complex professional reception was the role assigned by Darwin to the importance of normal individual variation as the source of evolutionary novelty. As we have seen, Darwin had relied on the novel claim that small individual variations—the kind of differences considered by an earlier tradition as merely “accidental”—formed the raw material upon which, by cumulative directional change under the action of natural selection, major changes could be produced sufficient to explain the origin and subsequent differences in all the various forms of life over time. Darwin, however, left the specific causes of this variation unspecified beyond some effect of the environment on the sexual organs. Variation was presented in the Origin with the statement that “the laws governing inheritance are quite unknown” (Darwin 1859 [1964], 13). In keeping with his commitment to the gradualism of Lyellian geology, Darwin also rejected the role of major “sports” or other sources of discontinuous change in this process.

As critics focused their attacks on the claim that such micro-differences between individuals could be accumulated over time without natural limits, Darwin began a series of modifications and revisions of the theory through a back and forth dialogue with his critics that can be followed in his revisions to the text of the Origin . In the fourth edition of 1866, for example, Darwin inserted the claim that the continuous gradualism depicted by his branching diagram was misleading, and that transformative change does not necessarily go on continuously. “It is far more probable that each form remains for long periods unaltered, and then again undergoes modification” (Darwin 1866, 132; Peckham 2006, 213). This change-stasis-change model allowed variation to stabilize for a period of time around a mean value from which additional change could then resume. Such a model would, however, presumably require even more time for its working than the multi-millions of years assumed in the original presentation of the theory.

The difficulties in Darwin’s arguments that had emerged by 1866 were highlighted in a lengthy and telling critique in 1867 by the Scottish engineer Henry Fleeming Jenkin (1833–1885) (typically Fleeming Jenkin). Using an argument previously raised in the 1830s by Charles Lyell against Lamarck, Fleeming Jenkin cited empirical evidence from domestic breeding that suggested a distinct limitation on the degree to which normal variation could be added upon by selection (Fleeming Jenkin 1867 in Hull 1973). Using a loosely mathematical argument, Fleeming Jenkin argued that the effects of intercrossing would continuously swamp deviations from the mean values of characters and result in a tendency of the variation in a population to return to mean values over time. It is also argued that domestic evidence does not warrant an argument for species change. For Fleeming Jenkin, Darwin’s reliance on continuous additive deviation was presumed to be undermined by these arguments, and only more dramatic and discontinuous change—something Darwin explicitly rejected—could account for the origin of new species.

Fleeming Jenkin also argued that the time needed by Darwin’s theory to account for the history of life under the gradual working of natural selection was simply unavailable from scientific evidence, supporting this claim by an appeal to the physical calculations of the probable age of the solar system presented in publications by his mentor, the Glasgow physicist William Thompson (Lord Kelvin, 1824–1907) (Burchfield 1975). On the basis of Thompson’s quantitative physical arguments concerning the age of the sun and solar system, Fleeming Jenkin judged the time since the presumed first beginnings of life to be insufficient for the Darwinian gradualist theory of species transformation to have taken place.

Jenkin’s multi-pronged argument gave Darwin considerable difficulties and set the stage for more detailed empirical inquiries into variation and its causes by Darwin’s successors. The time difficulties were only resolved in the twentieth-century with the discovery of radioactivity that could explain why the sun did not lose heat in accord with Newtonian principles.

As a solution to the variation question, Darwin developed his “provisional hypothesis” of pangenesis, which he presented the year after the appearance of the Fleeming Jenkin review in his two-volume Variation of Plants and Animals Under Domestication (Darwin 1868; Olby 2013). Although this theory had been formulated independently of the Jenkin review (Olby 1963), in effect it functioned as Darwin’s reply to Jenkin’s critique. The pangenesis theory offered a causal theory of variation and inheritance through a return to a theory resembling Buffon’s theory of the organic molecules proposed in the previous century (see entry on evolutionary thought before Darwin section 3.2). Invisible material “gemmules” were presumed to exist within the cells. According to theory, these were subject to external alteration by the environment and other external causes. The gemmules were then shed continually into the blood stream (the “transport” hypothesis) and assembled by “mutual affinity for each other, leading to their aggregation either into buds or into the sexual elements” (Darwin 1868, vol. 2, 375). In this form they were then transmitted—the details were not explained—by sexual generation to the next generation to form the new organism out of “the modified physiological units of which the organism is built” (ibid., 377). In Darwin’s view, this hypothesis united together numerous issues into a coherent and causal theory of inheritance and explained the basis of variation. It also explained how use-disuse inheritance, a theory which Darwin never abandoned, could work.

The pangenesis theory, although not specifically referred to, seems to be behind an important distinction Darwin inserted into the fifth edition of the Origin of 1869 in his direct reply to the criticisms of Jenkin. In this textual revision, Darwin distinguished “certain variations, which no one would rank as mere individual differences”, from ordinary variations (Darwin1869, 105; Peckham 2006, 178–179). This revision shifted Darwin’s emphasis away from his early reliance on normal slight individual variation, and gave new status to what he now termed “strongly marked” variations. The latter were now the forms of variation to be given primary evolutionary significance. Presumably this strong variation was more likely to be transmitted to the offspring, although details are left unclear, and in this form major variation could presumably be maintained in a population against the tendency to swamping by intercrossing as Fleeming Jenkin had argued.

Darwin’s struggles over this issue defined a set of problems that British life scientists in particular were to deal with into the 1930s. These debates over the role of somatic variation in the evolutionary process placed Darwinism in a defensive posture that forced its supporters into major revisions in the Darwinian research program (Gayon 1998; Vorzimmer 1970). The consequence was a complex period of Darwinian history in which natural selection theory was rejected by many research, or defended in modified form by others (Bowler 1983, 2013a; Largent 2009).

4. Human Evolution and the Descent of Man

Darwin had retained his own conclusions on human evolution quietly in the background through the 1860’s while the defense of his general theory was conducted by advocates as diverse as Thomas Henry Huxley (1825–95) in England, Asa Gray (1810–88) in the United States, and Ernst Haeckel (1834–1919) in the emerging new Germany. Darwin’s own position on the “human question” remained unclear to the reading public, and his rhetorical situating of the Origin within a tradition of divine creation by secondary law, captured in the frontispiece quotations from William Whewell and Francis Bacon, allowed many before 1871 to see Darwin as more open to religious interpretations of human origins than those of some of his popularizers.

Darwin’s interest in developing his insights into the origins of human beings and the explanation of human properties through descent with modification was, however, evident in his correspondence as early as January of 1860 when he began collecting evidence on the expressions of the emotions in human beings (Browne 2002, chp. 9). He then developed a questionnaire specifically intended to gain such information from contacts in Patagonia and Tierra del Fuego (Radick 2018). Further engagement with these issues was then generated by the discussions of Lyell (1863) and A. R. Wallace (1864), both of whom suggested that natural selection could not account for the development of the “higher” rational faculties, language, and ethical motivation (R. J. Richards 1987, chp. 4). It was then in February of 1867 that Darwin decided to remove material from his massive manuscript of the Variation of Plants and Animals Under Domestication to create a “very small volume, ‘an essay on the origin of mankind’” (Darwin to Hooker, 8 February 1867 and CD to Turner, 11 February 1867, Burkhardt, Correspondence 15: 74, 80). At this time he also sent to several international correspondents a more detailed questionnaire asking for information on human emotional expression. Further impetus to develop his views was created by the arguments of William R. Greg (1809–1881) in an essay in Fraser’s Magazine (1868), with further support by arguments of A. R. Wallace in 1869, both of whom drew a sharp distinction between human properties and those of animals (R. J. Richards 1987, 172–184). These arguments denied that natural selection could explain the origins of these “higher powers”.

Darwin’s drafting of his views on human issues, begun in early 1868, expanded into a major enterprise in which he became deeply engaged with the issue of the implications of his theory for ethics. The result of this effort devoted to anthropological topics was two separate works: the Descent of Man and Selection in Relation to Sex , delivered to the publisher in June of 1870 with publication in 1871, and its companion, Expression of the Emotions in Man and Animals , which he commenced in early 1871 with publication in early 1872.

As commentators have noted, these two works differ markedly in their arguments, and reflect different relationships to Darwin’s causal theories of natural and sexual selection, with sexual selection predominting over natural selection for the major portion of the Descent , and both of these causal theories generally missing from the descriptive approach of the Expression (Radick 2018).

Sexual selection—the choosing of females by males or vice versa for breeding purposes—had received a general statement by Darwin in Chapter IV of the Origin , but this played only a minor role in the original argument, and its importance was denied by co-evolutionist A. R. Wallace. In the Descent this was now developed in extensive detail as a major factor in evolution that could even work against ordinary natural selection. Sexual selection could be marshaled to explain sexual dimorphism, and also the presence of unusual characters and properties of organisms—elaborate feeding organs, bright colors, and other seemingly maladaptive structures such as the antlers on the Irish Elk or the great horn on the Rhinoceros beetle—that would appear anomalous outcomes of ordinary natural selection working for the optimal survival of organisms in nature. In a dramatic extension of the principle to human beings, the combination of natural and sexual selection is used to explain the origins of human beings from simian ancestors. It also accounts for the sexual dimorphism in humans, and is a major factor accounting for the origin of human races (E. Richards 2017; R. A. Richards 2013).

Although the secondary causal role of sexual selection in the development of species generally was to be the main topic of the bulk of the Descent , this plays an ambiguous role initially in the “treatise on man” that occupies the initial chapters, and functions differently in his treatment of the origins of mental powers, the moral sense, and the origin of races in this opening discussion.

In constructing this presentation, Darwin reaches back to the early Notebooks that he had separated out from the “transformist” discussions to deal with his inquiries into ethics, psychology, and emotions (see Section 1.2 above). Of particular importance for the opening discussions of the Descent was the “M” notebook, commenced in July of 1838, and “N”, begun in October of that year. On occasion he also samples the collection of entries now entitled “Old and Useless Notes”, generally written between 1838 and 1840.

The initial topic of focus in the Descent deals with the far-reaching issues concerning the status and origin of human mental properties, faculties presumed traditionally to be possessed uniquely by human beings. These properties Darwin now places on an evolutionary continuum with those features of animal behavior long regarded as instinctual. In this he placed himself in opposition to the long tradition of discourse that had distinguished humans from animals due to the possession of a “rational principle” related to their possession of a rational soul. This tradition had been given a more radical foundation in the revolutionary reflections on the relation of mind and body initiated by René Descartes (1596–1650) in the middle of the seventeenth century. Descartes deepened this distinction with the separation of the two substances—thinking substance, or res cogitans , possessed only by humans, and extended material substance, res extensa that constituted the rest of the natural world, including animals and plants, rendering animals only lifeless machines without rational faculties.

Darwin’s collapse of this Cartesian barrier with his theory of human origins outlined in the Descent continued a discussion that had been a concern of his transformist predecessors, especially Jean Baptiste Lamarck (Sloan 1999). But Darwin took this issue to a new level as he interpreted the human-animal relationship in the context of his novel theory of divergent evolution from common ancestors. Darwin also broke with the view of humans as the summit of a natural teleological process. Darwin instead denies such teleological ordering, and effectively reduces human properties to those of animals—mental as well as physical—by tracing them to their origin in properties of lower organisms.

The warrant for the identification of human and animal mental properties, however, is not supported by substantial argumentation in the Descent. The opening discussions of the treatise summarize the anatomical evidence for “homologies” —true identities—between humans and animals due to descent from common ancestors, claims already set out in Chapter Thirteen of the Origin. But the transferal of this identity of structure to inner non-anatomical “mental” properties rested on premises that are not made explicit in this text, and were not identities drawn by Huxley, Wallace and Lyell, for example, in their treatments of humans in relation to evolutionary theory, although they acknowledged the anatomical continuities.

To understand Darwin’s arguments, it is useful to return to his Notebook discussions on which he was drawing for his reasoning (see above, Section 1.2). In his “C” Notebook, opened in February of 1838, Darwin has a remarkable entry that displays very early on his commitment to a metaphysical “monism”—the thesis that there is only one substance underlying both mind and body. With this goes the thesis of a parallelism of the complexity of mental properties with those of material structure. In this entry in “C” following on Darwin’s reflections on the issue of instinct, and also recording some of his observations on animals at the Regents Park zoological gardens, Darwin comments:

There is one living spirit, prevalent over this wor[l]d, (subject to certain contingencies of organic matter & chiefly heat), which assumes a multitude of forms <<each having acting principle>> according to subordinate laws.—There is one thinking […] principle (intimately allied to one kind of organic matter—brain. & which <prin> thinking principle. seems to be given or assumed according to a more extended relations [ sic ] of the individuals, whereby choice with memory, or reason ? is necessary.—) which is modified into endless forms, bearing a close relation in degree & kind to the endless forms of the living beings.— We see thus Unity in thinking and acting principle in the various shades of <dif> separation between those individuals thus endowed, & the community of mind, even in the tendency to delicate emotions between races, & recurrent habits in animals.— (Barrett 1987, 305)

As we follow these issues into the “M” Notebook, the assumption of a single “thinking principle,” allied to one kind of organic matter, seems then to underlie Darwin’s subsequent reflections on mind and matter. The “M” Notebook cites numerous “mental”properties common to humans and animals that generally parallel levels of material organization, similar to the identities expressed in the later Descent. The range of this universal extension of mental properties is far-reaching in these early discussions: consciousness and “free will” extends to all animals, including invertebrates:

With respect to free will, seeing a puppy playing cannot doubt that they have free will, if so all animals., then an oyster has & a polype (& a plant in some senses […]; now free will of oyster, one can fancy to be direct effect of organization, by the capacities its senses give it of pain or pleasure, if so free will is to mind, what chance is to matter […] (Barrett 1987, 536).

When these themes reappear in Chapter Two of the first edition of the Descent , Darwin seems to draw implicitly upon this matter-mind identity theory as an obvious consequence of his theory of descent from common ancestry. There he enumerates a long list of traditional human mental and emotional properties to claim that each of them are identities with the properties of simpler forms of life. The list is expansive: courage, deceit, play, kindness, maternal affection, self-complacency, pride, shame, sense of honor, wonder, dread, imitation, imagination, and dreaming. All are considered to be represented in a wide range of animals, with “play”and “recognition” found even in the ants.

When he addresses the more complex mental properties that specifically had been considered by a long tradition of discussion to be the distinctive human properties—possession of language, reason, abstract conceptual thinking, self-reflection—these again are treated as having their manifestations in other forms of life, with none of them unique to human beings. Language, the property that Descartes, for example, had considered to be the primary distinguishing character denoting the human possession of mind as distinct from matter, Darwin treats a developing in a gradual process from animal sounds that parallel the differentiation of species, illustrated by the fact that languages “like organic beings, can be classed in groups under groups” (Darwin 1871 [1981], 60). He closes his discussion of mental powers with an analysis of religious belief that derives it from imagination and belief in spirits found in aboriginal peoples. It can even be homologized with the “deep love of a dog for his master, associated with complete submissions, some fear, and perhaps other feelings” (ibid., 68). Darwin’s discussions of the relation of human and animal mental and emotional properties would set the agenda for a complex discussion that would carry into contemporary debates over animal cognition and the relations of human and animal properties (see the entries on animal cognition ; methods in comparative cognition ; and animal consciousness ).

The subsequent treatment of ethical issues in the third chapter of the Descent was for Darwin a topic to be approached “exclusively from the side of natural history” (ibid., 71). This issue also presented him with some of his most difficult conceptual problems (CD to Gray, 15 March 1870, Burkhardt, Correspondence 18, 68). In this discussion he also employs natural selection theory as an explanatory cause.

Under the heading of “Moral Sense”, Darwin offered some innovations in ethics that do not easily map on to standard ethical positions classified around the familiar categories of Rule or Act Utilitarianism, Kantian Deontology, Hedonism, and Emotivism. Darwin’s closest historical affinities are with the Scottish “Moral Sense” tradition of Frances Hutcheson (1694–1746), Adam Smith (1723?–1790), and David Hume (1711–1776). More immediately Darwin drew from the expositions of the moral sense theory by his distant relative, Sir James Macintosh (1765–1832) (R. J. Richards 1987, 114–122, 206–219).

Traditional moral sense theory linked ethical behavior to an innate property that was considered to be universal in human beings, although it required education and cultivation to reach its full expression (see the entry on moral sentimentalism ). This inherent property, or “moral” sense, presumably explained such phenomena as ethical conscience, the sense of moral duty, and it accounted for altruistic actions that could not be reduced to hedonic seeking of pleasure and avoiding pain. It also did not involve the rational calculation of advantage, or the maximization of greatest happiness by an individual prior to action, as implied by Utilitarianism. For this reason Darwin criticized John Stuart Mill’s version of Utilitarian theory because it relied on acquired habits and the calculation of advantage (Darwin 1871 [1981], 71n5).

Darwin’s reinterpretation of the moral sense tradition within his evolutionary framework also implied important transfomations of this theory of ethics. The moral sense was not to be distinguished from animal instinct but was instead derived historically from the social instincts and developed by natural selection. From this perspective, Darwin could claim a genuine identity of ethical foundations holding between humans and animals, with the precursors of human ethical behavior found in the behavior of other animals, particularly those with social organization. Natural selection then shaped these ethical instincts in ways that favored group survival over immediate individual benefit (ibid., 98). Human ethical behavior is therefore grounded in a natural property developed by natural selection, with the consequence that ethical actions can occur without moral calculus or rational deliberation.

When moral conflict occurs, this is generally attributed to a conflict of instincts, with the stronger of two conflicting instincts favored by natural selection insofar as it favors group benefit (ibid. 84). In human beings the “more enduring Social Instincts” thus come to override the less persistent “individual” instincts.

The adequacy of evolutionary ethical naturalism as a foundation for ethical realism proved to be a point of contention for Darwin’s contemporaries and successors following the publication of the Descent . For some moral philosophers, Darwin had simply reduced ethics to a property subject to the relativizing tendencies of natural selection (Farber 1994: chp. 5). It was, in the view of Darwin’s philosophical critics, to reduce ethics to biology and in doing so, to offer no way to distinguish ethical goods from survival advantages. Not even for some strong supporters of Darwinism, such as Thomas Huxley and Alfred Russel Wallace, was Darwin’s account adequate (ibid., chp. 4). Much of subsequent development of moral philosophy after Darwin would be grounded upon the canonical acceptance of the “is-ought” distinction, which emerged with new force from the critique of “evolutionary” ethical theory. This critique began with Thomas Huxley’s own break with Darwinian ethical theory in his Romanes Lecture, “Evolution and Ethics”of 1893 (Huxley 1893). This lecture, reflecting Huxley’s views eleven years after Darwin’s death, would play an important role in the Chinese reception of Darwinism (Huxley 1895; see above, section 3.1). This line of critique also received an influential academic expression in G. E. Moore’s (1873–1958) Principia Ethica —itself an attack on Spencer’s version of evolutionary ethics (Moore 1903). Debates over the adequacy of evolutionary ethics continue into the present (see the entries on biological altruism and morality and evolutionary biology ; see also, R. J. Richards 2015, 2009, 1999, 1987, Appendix 2; Charmetant 2013; Boniolo and DeAnna (eds.) 2006; Hauser 2006; Katz (ed.) 2000; Maienschein and Ruse (eds.) 1999).

4.4 Reception of the Descent

The international reception of the Descent of Man and Expression of the Emotions is a topic in need of the kind of detailed studies that surround the historical impact of the Origin. These works presented the reading public after 1871 with a more radical and controversial Darwin than had been associated with the author of the popular Journal of Researches or even the Origin itself, and his anthropological works created a watershed in the public reception of Darwin’s views (Radick 2013). The Descent finally made public Darwin’s more radical conclusions about human origins, and seemed to many of his readers, even those previously sympathetic to the Origin , to throw Darwin’s authority behind materialist and anti-religious forces. Public knowledge of Darwin’s own conclusions on human evolution before 1871 had rested on the one vague sentence on the issue in the Origin itself. The Descent made public his more radical conclusions. Even though the question of human evolution had already been dealt with in part by Thomas Huxley in his Man’s Place in Nature of 1863 (Huxley 1863), and by Charles Lyell in the same year in his Geological Evidences of the Antiquity of Man (Lyell 1863), followed by Alfred Russel Wallace’s articles in 1864 and 1870 (Wallace 1864 and online), these authors had either not dealt with the full range of questions presented by the inclusion of human beings in the evolutionary process, or they had emphasized the moral and mental discontinuity between humans and animals. Only Ernst Heinrich Haeckel had drawn out a more general reductive conception of humanity from evolutionary theory and he had not ventured into the specific issues of ethics, social organization, the origins of human races, and the relation of human mental properties to those of animals, all of which are dealt with in the Descent . Darwin’s treatise presented, as one commentator has put it, “a closer resemblance to Darwin’s early naturalistic vision than anything else he ever published” (Durant 1985, 294).

Darwin’s extension of his theory to a range of questions traditionally discussed within philosophy, theology, and social and political theory, has shaped the more general history of Darwinism since the 1870s. It set the agenda for much of the development of psychology of the late nineteenth century (R. J. Richards 1987). It also hardened the opposition of many religiously-based communities against evolutionary theory, although here again, distinctions must be made between different communities (Ellegård 1990, chp. 14). Such opposition was not simply based upon the denial of the literal scriptural account of the origins of humankind, an issue that played out differently within the main religious denominations (Haught 2013; Finnegan 2013; Swetlitz 2013; Artigas, Glick, & Martinez 2006; Moore 1979). The more fundamental opposition was due to the denial of distinctions, other than those of degree, between fundamental human properties and those of animals.

Furthermore, the apparent denial of some kind of divine guidance in the processes behind human evolution and the non-teleological character of Darwin’s final formulations of the natural selection theory in the fifth and sixth editions of the Origin , hardened this opposition. His adoption from Herbert Spencer of designator “survival of the fittest” as a synonym for “natural selection” in the fifth edition of 1869 added to this growing opposition. As a consequence, the favorable readings that many influential religious thinkers—John Henry Newman (1801–1890) is a good example—had given to the original Origin , disappeared. The rhetoric of the Descent , with its conclusion that “man is descended from a hairy quadruped, furnished with a tail and pointed ears” (Darwin 1871 [1981], 389), presented to the public a different Darwin than many had associated with the popular seagoing naturalist.

The new opposition to Darwin is reflected in the many hostile reviews of the Descent to appear in the periodical press (R. J. Richards 1987, 219–230). Particularly at issue were Darwin’s accounts of the origin of ethical principles and intelletual powers, including language, self-reflection, abstract thinking and religious belief as derivations from animal properties (Anon. 1871)

The profound revolution in thought that Darwin created, however, was eventually recognized even by his one-time harsh critics. The once leading British comparative anatomist Richard Owen (1804–1892), who had long been estranged from Darwin since his harsh review of the Origin in 1860, nonetheless could comment on the occasion of Darwin’s burial in Westminster Abbey in a letter to Horace Walpole:

The great value of Darwin’s series of works, summarizing all the evidence of Embryology, Paleontology, & Physiology experimentally applied in producing Varieties of Species, is exemplified in the general acceptance by Biologists of the Secondary Law, by Evolution, of the ‘Origin of Species’ […] In this respect Charles Darwin stands to Biology in the relation which Copernicus stood to Astronomy. […] [Copernicus] knew not how the planets revolved around the sun. To know that required the successive labours of a Galileo, a Kepler and finally a Newton […] Meanwhile our British Copernicus of Biology merits the honour and the gratitude of the Empire, which is manifest by a Statue in Westminster Abbey. (Richard Owen to Horace Walpole, 5 November, 1882, Royal College of Surgeons of England Archives, MS0025/1/5/4).

The subsequent history of the debates surrounding Darwin’s achievement forms a complex story that involves much of the history of life science, as well as ethical theory, psychology, philosophy, theology and social theory since 1870. For a general summary of recent scholarship see Ruse 2013a and articles from this encyclopedia listed below.

This article has intended to give a historical overview of the specific nature of Darwinian theory, and outline the ways in which it differed from the theories of predecessors in the nineteenth century (see the entry evolution before Darwin ). The eventual general consensus achieved by the middle of the twentieth century around the so-named “Synthetic” theory of evolution that would combine population genetics with a mathematical analysis of evolutionary change, has formed a successful research program for more than half a century (Smocovitis 1996; Mayr and Provine 1980; Provine 1971). This “synthesis” has been challenged in recent decades by the current movement known as evolutionary developmental theory, or “evo-devo”. This development represents in some important respects a return to presumably discarded traditions and lines of exploration of the nineteenth and early twentieth centuries which sought to link evolution with embryological development, and to a complex understanding of genetics, with re-examination of the effects of external conditions on inheritance (Gilbert 2015; Newman 2015; Laubichler and Maienschein 2007; Gissis and Jablonka 2011; Pigliucci and Müller 2010; Amundson 2005; Gilbert, Opitz and Raff 1996). Where these debates and revisions in evolutionary theory may lead in another fifty years is a matter of speculation (Gayon 2015 in Sloan, McKenny and Eggleson 2015).

More general philosophical issues associated with evolutionary theory—those surrounding natural teleology, ethics, the relation of evolutionary naturalism to the claims of religious traditions, the implications for the relation of human beings to the rest of the organic world—continue as issues of scholarly inquiry. The status of Darwin’s accounts of human mental powers and moral properties continue to be issues of philosophical debate. The adequacy of his reliance on sexual selection to explain sex and gender roles in human society form heated topics in some feminist scholarship. Such developments suggest that there are still substantial theoretical issues at stake that may alter the future understanding of evolutionary theory in important ways (Sloan, McKenny, & Eggleson [eds] 2015).

• Amundson, Ron, 2005, The Changing Role of the Embryo in Evolutionary Thought: Roots of Evo-Devo , Cambridge: Cambridge University Press. doi:10.1017/CBO9781139164856
• Anon., “Review of the Descent of Man and Selection in Relation to Sex” , Edinburgh Review 134 (July 1871), 195–235.
• Artigas, Mariano, Thomas F. Glick, and Rafael A. Martínez, 2006, Negotiating Darwin: The Vatican Confronts Evolution, 1877–1902 , Baltimore, MD: Johns Hopkins University Press.
• Barrett, Paul H., Peter J. Gautrey, Sandra Herbert, David Kohn, and Sydney Smith (eds.), 1987, Charles Darwin’s Notebooks: 1836–1844 , Cambridge: Cambridge University Press. [online manuscripts at Darwin’s notebooks and reading lists.]
• Beatty, John 1985, “Speaking of Species: Darwin’s Strategy”, in Kohn 1985a: 265–281. doi:10.1515/9781400854714.265
• Bernard, Claude, 1865 [1957], Introduction to the Study of Experimental Medicine , translated Henry Copley Greene, New York: Dover. Originally published in 1927, New York:Macmillan. [ Bernard 1865 available online ]
• Boniolo, Giovanni and Gabriele De Anna (eds.) 2006, Evolutionary Ethics an Contemporary Biology, Cambridge: Cambridge University Press.
• Bowlby, John, 1990, Charles Darwin: A New Life , New York: Norton.
• Bowler, Peter J., 1976, Fossils and Progress: Paleontology and the Idea of Progressive Evolution in the Nineteenth Century , New York: Science History.
• –––, 1983, The Eclipse of Darwinism: Anti-Darwinian Evolution Theories in the Decades Around 1900 , Baltimore, MD: Johns Hopkins University Press.
• –––, 1990, Charles Darwin: The Man and His Influence , Oxford: Blackwell.
• –––, 1996, Life’s Splendid Drama: Evolutionary Biology and the Reconstruction of Life’s Ancestry, 1860–1940 , Chicago: University of Chicago Press.
• –––, 2013a, “Darwinism in Britain”, in Ruse 2013a: 218–225. doi:10.1017/CBO9781139026895.028
• Browne, Janet, 1995, Charles Darwin: Voyaging , New York: Knopf.
• –––, 2002, Charles Darwin: The Power of Place , Princeton: Princeton University Press.
• Burchfield, Joe D., 1975, Lord Kelvin and the Age of the Earth , Chicago: University of Chicago Press.
• Burkhardt, Frederick et al., (eds.), 1985–2023, The Correspondence of Charles Darwin , 30 volumes. Cambridge: Cambridge University Press.
• Chambers, Robert, 1844 [1994], Vestiges of the Natural History of Creation , facsimile reprint of first edition, J. Secord (ed.), Chicago: University of Chicago Press. [ Chambers 1844 available online ]
• Charmetant, Erin. 2013,“Darwin and Ethics”, in Ruse 2013a, 188–194.
• Darwin, Charles Robert, 1836–1844 [1987], Charles Darwin’s Notebooks: 1836–1844 , Paul H. Barrett, Peter J. Gautrey, Sandra Herbert, David Kohn, and Sydney Smith (eds.), Cambridge: Cambridge University Press. See also the Darwin Online section on Darwin’s notebooks and reading lists .
• –––, 1856–1858 [1974], Charles Darwin’s “Natural Selection”, Being the Second Part of his Big Species Book Written from 1856 to 1858 , R.C. Stauffer (ed.), 1974, Cambridge: Cambridge University Press. [ Natural Selection 1974 available online ]
• –––, 1842 [1996], “1842 Sketch On Selection Under Domestication, Natural Selection, and Organic Beings in the Wild State”, selection in Glick and Kohn 1996, 89–99.
• –––, 1844a [1996], “1844 Essay: Variation of Organic Beings in the Wild State”, in Glick and Kohn 1996, 99–115.
• –––, 1859 [1964], On the Origin of Species By Means of Natural Selection , London: Murray. Facsimile reprint, ed. E. Mayr Cambridge, MA: Harvard University Press [ Origin first edition available online ]
• –––, 1860, second edition [ Origin second edition available online ]
• –––, 1861, third edition, [ Origin third edition available online ]
• –––, 1862, first French edition, De l’origine des espèces , Clémence Royer (trans.), Paris: Guillaumin. [ Origin French first edition available online ]
• –––, 1866, fourth edition, [ Origin fourth edition available online ]
• –––, 1869, fifth edition, [ Origin fifth edition available online ]
• –––, 1872, sixth edition, [ Origin sixth edition available online
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How to cite this entry . Preview the PDF version of this entry at the Friends of the SEP Society . Look up topics and thinkers related to this entry at the Internet Philosophy Ontology Project (InPhO). Enhanced bibliography for this entry at PhilPapers , with links to its database.

• The Complete Works of Charles Darwin Online , maintained by John van Wyhe, Cambridge University Library. In particular note the Darwin Papers & Manuscripts section
• Darwin Manuscripts Project , maintained by David Kohn in cooperation with the American Museum of Natural History Research Library.
• Letter to Charles Lyell, 28 September 1860, DCP-LETT-2931
• Letter from J.D. Hooker, 8 February 1867, DCP-LETT-5395
• Letter to William Turner, 11 February 1867, DCP-LETT-5398
• Letter to Asa Gray, 15 March 1870, DCP-LETT-7132
• Ghiselin, Michael T., 2009, Darwin: A Reader’s Guide [PDF], Occasional Papers of the California Academy of Sciences 155.
• The Huxley File , maintained by Charles Blinderman and David Joyce (Clark University).
• Works by Ernst Heinrich Haeckel , Project Gutenberg.
• Wallace Online , maintained by John van Wyhe, Cambridge University Library.

adaptationism | altruism | altruism: biological | animal: cognition | animal: consciousness | biology: philosophy of | comparative cognition, methods in | creationism | Darwinism | evolution: concept before Darwin | evolution: cultural | fitness | genetics: ecological | life | morality: and evolutionary biology | moral sentimentalism | natural selection | natural selection: units and levels of | Newton, Isaac: philosophy | species | Spencer, Herbert | teleology: teleological notions in biology | Whewell, William

The author wishes to acknowledge the valuable comments on this version of the article by David Depew, Gregory Radick, M. J. S. Hodge, Alan Love, and Xiaoxing Jin. Additional comments were made on an earlier version by Michael Ruse, Robert J. Richards, Edward Zalta, M. Katherine Tillman, and the anonymous reviewers for the Stanford Encyclopedia of Philosophy. I am particularly indebted to Dr. Xiaoxing Jin for information contained in his substantial doctoral work and subsequent research on the reception of Darwinism into China. Responsibility for all interpretations is my own.

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Library of Congress Catalog Data: ISSN 1095-5054

Charles Darwin’s Descent of Man , 150 Years Later

A new book on Darwin’s classic asks what he got right and wrong about “the highest and most interesting problem for the naturalist:” human evolution.

When Charles Darwin published On the Origin of Species in 1859, it outlined a new scientific theory. Darwin reasoned that populations of organisms evolve over generations through a process that he termed “natural selection.” His work offered evidence that the diversity of life on Earth arose by common descent through a brachiating pattern of evolution. Origin explained the diversity and existence of new plant and animal species, but Darwin tiptoed around the question of what exactly this process would mean for humans and our own biological beginnings.

It wasn’t until The Descent of Man, and Selection in Relation to Sex , published twelve years later, that Darwin picked up the question of human evolution specifically, calling the question of our species’ origin “the highest and most interesting problem for the naturalist.” The Descent of Man outlines the theory and evidence for human evolution that Darwin had amassed, as well as his arguments about the origins of civilizations, human races, and sex differences—such as the evidence for each was in 1871. Ever since its publication, Descent has prompted vigorous debate in scientific circles , to say nothing of the fervor it’s ignited within religious, political, and social groups .

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To celebrate The Descent of Man ’s sesquicentennial, the paleoanthropologist Jeremy DeSilva gathered a team of anthropologists (along with a historian and science writer) to update, interpret, and correct Darwin’s science. The result, A Most Interesting Problem: What Darwin Got Right and Wrong About Human Evolution is a fascinating, comprehensive, and accessible collection of essays.

Each chapter in A Most Interesting Problem tackles a chapter from Descent by situating Darwin’s work in his proper, historical context and then describing “what science knows now.” For example, in Chapter 1 of The Descent of Man , Darwin drew on evidence from comparative anatomy and embryology to show that similarities in the structure and embryonic development of living animals could provide clues about how human evolution unfolded. In short, Darwin argued that stages of an embryo’s development mimicked, “recapitulated,” an organism’s evolutionary history. In “The Fetus, the Fish Heart, and the Fruit Fly,” ­­Alice Roberts points out that while there are links between embryological development and evolutionary history, the specific “recapitulation” idea proposed by Darwin no longer holds up.

But rather than just offer a chapter-by-chapter critique of Descent , the essays in A Most Interesting Problem also explain how the study of human origins has unfolded in the subsequent 150 years, emerging as a vibrant scientific field full of exciting discoveries and new research questions. Each essay reminds readers that science—good science, that is—is “a collective enterprise that unfolds over generations as we test and retest old ideas and develop new ones to make sense of our world,” as DeSilva notes in the book’s preface.

Without a record of fossil hominins and DNA evidence to draw from—lines of evidence that have crucial importance for contemporary research—what did Darwin get right about human evolution in 1871? What did he get wrong? In a word, plenty.

In The Descent of Man , Darwin argued that humans evolved in Africa and, indeed, the fossil record shows a long history of hominins in Africa. “As a paleoanthropologist of African origin [of course, we are all Africans!], it gives me pride and honor to actually find ancient fossil remains of our ancestors in the continent that Darwin predicted they would be found,” the paleoanthropologist Yohannes Halie-Selassie notes. Darwin suggested that humans were not the only toolmakers and tool users on earth and that non-human cognition was significant. “Ever since Darwin, nonhuman primates, then non-primate mammals, and more recently birds have been awarded higher cognitive status than even Darwin himself might have suspected,” the neuroscientist Suzana Herculano-Houzel explains. Darwin claimed that morality appeared early in human evolution and wasn’t necessarily tied to the trappings of modern civilization. As the anthropologist Brian Hare points out: “We leave with the same radical conclusion that Darwin reached: Religion did not create our morality. What we might recognize as morality, in some nascent form, appeared with the birth of our species.”

But because science is nothing if not a product of its social and historical context, it turns out that Descent ’s legacy is complicated. One hundred and fifty years after Descent ’s publication, it’s easy to see that “ Descent of Man shows Darwin at his most Victorian,” as the historian of science Janet Browne astutely observes in the book’s introduction. It’s impossible to read Descent of Man and not be struck by how much Victorian sensibilities about race and sex permeate Darwin’s writings. The ideas were problematic then, and their legacy is problematic now. There is, in short, a lot of science that Darwin got wrong.

Specifically, Darwin’s idea that the history of human social organization follows a neat, linear trajectory of savagery to civilization is no longer de rigeur in archaeological and paleoanthropological research. The bioarchaeologist Kristina Killgrove emphasizes:

We no longer subscribe to the nineteenth-century ideas… [that] insisted that humans progress linearly from savagery to barbarism to civilization. Rather, we talk about different forms of societies in a more diversified way.

Darwin thought that human diversity could—and ought—to be described through race. “Our scientific understanding of genetics, human biology, and human evolution has advanced substantially since Darwin’s time. We can clearly and explicitly refute the hypothesis that humans are divided into ‘races’ [e.g., African, European, Asians, etc.] that are biological units,” the anthropologist Agustín Fuentes states. Finally, Darwin used his science to reinforce Victorian assumptions about sex and gender that can still be found today. As the anthropologist Holly Dunsworth argues:

We owe it to our species to break the link between Darwin’s inchoate offerings and their perceived social implications. Outdated science-inspired narratives alienate people from our shared-origins story, making it difficult for many people to claim it for themselves.

Perhaps the most compelling theme that underscores A Most Interesting Problem is the lack of sensationalism and hero-worship that Darwin—as a pivotal figure in the history of science—is often afforded. A Most Interesting Problem gives credit to Darwin where credit is due, but is unabashed in its systematic rejection of outdated science. “One hundred and fifty years after the publication of Descent , much of the public, including a cluster of academia, continues to repeat and perpetuate the same mistakes Darwin did. That must stop. We must challenge and refute racist pseudoscience,” Fuentes states. It’s important, in other words, to grapple with The Descent of Man : its legacy has implications for policy and society.

Fundamentally, Descent is a book about origins. It’s about origin stories and the science of understanding origins. A Most Interesting Problem reminds readers that research into human origins is an ongoing process, leaving us to wonder how the next 150 years of scientific study will continue to inform how we think about Darwin’s work, and to wonder what new discoveries will unfold.

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Charles Darwin and the Origin of Life

Juli peretó.

1 Institut Cavanilles de Biodiversitat i Biologia Evolutiva and Departament de Bioquímica i Biologia Molecular, Universitat de València, Apartat Postal 22085, 46071 València, Spain

Jeffrey L. Bada

2 Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92093-0212 USA

Antonio Lazcano

3 Facultad de Ciencias, UNAM, Apdo. Postal 70-407, Cd. Universitaria, 04510 Mexico D.F., Mexico

When Charles Darwin published The Origin of Species 150 years ago he consciously avoided discussing the origin of life. However, analysis of some other texts written by Darwin, and of the correspondence he exchanged with friends and colleagues demonstrates that he took for granted the possibility of a natural emergence of the first life forms. As shown by notes from the pages he excised from his private notebooks, as early as 1837 Darwin was convinced that “the intimate relation of Life with laws of chemical combination, & the universality of latter render spontaneous generation not improbable”. Like many of his contemporaries, Darwin rejected the idea that putrefaction of preexisting organic compounds could lead to the appearance of organisms. Although he favored the possibility that life could appear by natural processes from simple inorganic compounds, his reluctance to discuss the issue resulted from his recognition that at the time it was possible to undertake the experimental study of the emergence of life.

Introduction

What did Darwin think about the origin of life? His opinion seems to have changed over time from his original remark in the 1861 3rd edition of The Origin of Species «…it is no valid objection that science as yet throws no light on the far higher problem of the essence or origin of life», which he reiterated in a letter he mailed to his close friend Joseph Dalton Hooker on March 29, 1863, in which he wrote that «…it is mere rubbish thinking, at present, of origin of life; one might as well think of origin of matter». But yet, in a now famous paragraph in the letter sent to the same addressee on February 1st, 1871, he stated that «it is often said that all the conditions for the first production of a living being are now present, which could ever have been present. But if (and oh what a big if) we could conceive in some warm little pond with all sort of ammonia and phosphoric salts,—light, heat, electricity present, that a protein compound was chemically formed, ready to undergo still more complex changes, at the present such matter would be instantly devoured, or absorbed, which would not have been the case before living creatures were formed [...]».

Darwin’s opinions on the origin of the first organisms thus varied somewhat during his life, but never lead to the dramatic shift that could be implied by reading only the two paragraphs included. Indeed, a careful examination and critical reading of his public and private writings shows that what appear to be contradictory opinions on the problem of the emergence of life are the result of texts read out of context, sometimes maliciously, as shown by some publications of creationist groups and advocates of the so-called intelligent design.

Darwin was a meticulous writer who kept detailed diaries and excellent records of his extensive correspondence. This allows a detailed examination of the development of his ideas, a task facilitated not only by examining the books and articles he published during his lifetime, but also by the online availability of his correspondence and notebooks, including the pages that Darwin himself excised from them but which have survived.

Any attempt to study in detail Darwin’s ideas on the origin of life must consider the work of Farley ( 1977 ) and Strick ( 2000 ). Our own analysis has been greatly facilitated by the detailed cross-references and bibliographical analyses available at The Darwin Correspondence Project (Jim Secord, http://www.darwinproject.ac.uk/ ) and The Complete Work of Charles Darwin Online (John van Wyhe, http://darwin-online.org.uk/ ). What we report here is not an exhaustive examination of all the phrases, sentences, letters or paragraphs in which Darwin touched in one way or another on the problem of the origins of life, or related issues like spontaneous generation or archebiosis. We have not included, for instance, his epistolary exchanges with W. H. Dallinger or his extensive correspondence with John Tyndall, in which the later described his efforts to study spontaneous generation. Some original material was unavailable to us, and it is likely that in the future more letters and notes will be discovered. However, what is available demonstrates that for Charles Darwin the origin of life was an issue that could be analyzed scientifically, even if he recognized that the times were not ripe for doing so.

The Appearance of Life and the Origin of Species: Two Separate Issues

«The chief defect of the Darwinian theory is that it throws no light on the origin of the primitive organism—probably a simple cell—from which all the others have descended. When Darwin assumes a special creative act for this first species, he is not consistent, and, I think, not quite sincere...» wrote Haeckel in 1862 in a footnote in his monograph on the radiolaria (Haeckel 1862 ). His criticism was accurate but surprising, given the boundless admiration that he had for Darwin. Haeckel was not alone in raising the issue. When the German geologist Heinrich George Bronn, translated The Origin of Species , in 1860 , he did not hesitate to add a chapter of his own in which he discussed spontaneous generation in the context of Darwin’s theory. That very same year Bronn published an essay in which he argued quite emphatically that Darwin’s theory was incomplete until it could account for the origin of life, adding that some observations by Priestley, Pouchet and others could provide an example of spontaneous generation.

Darwin did not take exception to Haeckel’s remarks, nor was he impressed by Bronn’s criticisms. On February 16, 1860 he mailed to Lyell his own copy of Bronn’s Jahrbuch fur Mineralogie , and wrote that [ www.darwinproject.ac.uk/ ] [Letter 2703]:

«The united intellect of my family has vainly tried to make it out—I never tried such confoundedly hard German: nor does it seem worth the labour,—He sticks to Priestley’s green matter & seems to think that till it can be shown how life arises, it is no good showing how the forms of life arise. This seems to me about as logical (comparing very great things with little) as to say it was no use in Newton showing laws of attraction of gravity & consequent movements of the Planets, because he could not show what the attraction of Gravity is».

Everything that is known about Darwin’s personality suggests that he was sincerely uneasy comparing his work to Newton’s. Nevertheless, in the 1861 3rd edition of The Origin of Species , he pursued the analogy in order to underline the distinction between the origin and nature of life, and the understanding of the processes underlying its evolution: «I have now recapitulated the chief facts and considerations which have thoroughly convinced me that species have been modified, during a long course of descent, by the preservation or the natural selection of many successive slight favourable variations. I cannot believe that a false theory would explain, as it seems to me that the theory of natural selection does explain, the several large classes of facts above specified. It is no valid objection that science as yet throws no light on the far higher problem of the essence or origin of life. Who can explain what is the essence of the attraction of gravity? No one now objects to following out the results consequent on this unknown element of attraction; notwithstanding that Leibnitz formerly accused Newton of introducing “occult qualities and miracles into philosophy”» (Peckham 1959 :748).

Darwin raised the issue again in 1868, when he published The Variation of Animals and Plants under Domestication . In this book he wrote «It is the consideration and explanation of such facts as these which has convinced me that the theory of descent with modification by means of natural selection is in the main true. These facts have as yet received no explanation on the theory of independent Creations; they cannot be grouped together under one point of view, but each has to be considered as an ultimate fact. As the first origin of life on this earth, as well as the continued life of each individual, is at present quite beyond the scope of science, I do not wish to lay much stress on the greater simplicity of the view of a few forms, or of only one form, having been originally created, instead of innumerable miraculous creations having been necessary at innumerable periods; though this more simple view accords well with Maupertuis’s philosophical axiom ‘of least action’» (Darwin 1868 , Vol 1:12).

Heterogenesis, Archebiosis and Spontaneous Generation: A Cautionary Note on Nomenclature

Analysis of Darwin’s views on the origin of life and those of his contemporaries must take into account that during the 19th century the usage of the term “spontaneous generation” was open to different interpretations. As underlined by Farley ( 1977 ), Strick ( 2000 ) and Raulin-Cerceau ( 2004 ), debates on the existence or denial of spontaneous generation included a major distinction between two largely forgotten terms, i.e., heterogenesis and archebiosis . According to Henry Charlton Bastian, one of the most prominent characters during the Victorian origin-of-life debates, archebiosis refers to the “origin of living things from not-living materials” whereas heterogenesis was “the possibility of living things arising by previously unknown methods from the matter of pre-existing living things”, which could be decaying or not (Bastian 1907 ; Strick 2000 ).

Darwin read critically Bastian’s 1872 book The Beginnings of Life . Although he was not convinced in full, he did accept the possibility of a natural origin of life from non-living matter, and wrote to Wallace [Letter 8488] (Strick 2000 ),

«My Dear Wallace,—I have at last finished the gigantic job of reading Dr. Bastian’s book and have been deeply interested by it. You wished to hear my impression, but it is not worth sending. He seems to me an extremely able man, as, indeed, I thought when I read his first essay. His general argument in favour of Archebiosis is wonderfully strong, though I cannot think much of some few of his arguments. The result is that I am bewildered and astonished by his statements, but am not convinced, though, on the whole, it seems to me probable that Archebiosis is true».

And he added, in a letter to Haeckel in 1872 [Letter 8506] (Strick 2000 ) that «[O]ur English Dr. Bastian has lately published a book on so-called Spontaneous Generation, which has perplexed me greatly. He has collected all the observations made by various naturalists, some of them good observers, on the protoplasm within the cells of dying plants and animals becoming converted into living organisms. He has also made many experiments with boiled infusions in closed flasks; but I believe he is not a very careful observer. Nevertheless, the general argument in favor of living forms being now produced under favorable conditions seems to me strong; but I can form no final conclusions».

Always the faithful friend and follower, in 1876 Haeckel mailed Darwin a copy of his recently published The History of Creation . Darwin wrote back thanking him but also viewed with caution Haeckel’s endorsement of spontaneous generation (Darwin 1887 , Vol 3:180),

«My dear Häckel,—I thank you for the present of your book, and I am heartily glad to see its great success. You will do a wonderful amount of good in spreading the doctrine of Evolution, supporting it as you do by so many original observations. [...] I will at the same time send a paper which has interested me; it need not be returned. It contains a singular statement bearing on so-called Spontaneous Generation. I much wish that this latter question could be settled, but I see no prospect of it. If it could be proved true this would be most important to us [...].

Wishing you every success in your admirable labours,

I remain, my dear Häckel, yours very sincerely».

Hiding Ideas in a Decaying Mass of Mud

On March 28, 1863 the Athenæum, the very exclusive social club located at Carlton House Pall Mall London whose members included politicians, clergymen, gentlemen of fortune, journalists and naturalists, published an anonymous review of the Introduction to the Study of the Foraminifera that the distinguished physician and naturalist Walter Benjamin Carpenter had written the year before. That very same day Hooker mailed a copy to Darwin. The review was soon shown to have been written by Richard Owen, who argued in it that foraminifera and other microscopic organisms could periodically form spontaneously in mud due to an undefined “general polarizing force”, and harshly criticized Darwin by stating that he “could only express” the creative force responsible for the origin of life “in Pentateuchal terms as the primordial form into which life was first breathed!”.

The next day Darwin sent a letter to Hooker thanking him for the copy of the Athenæum publication, and commented ironically on Owen’s arguments [ www.darwinproject.ac.uk/ ] [Letter 4065],

«[…] Many thanks for Athenæum, received this morning & to be returned tomorrow morning. Who would have ever thought of the old stupid Athenæum taking to Oken-like transcendental philosophy written in Owenian style! It will be some time before we see “slime, snot or protoplasm” (what an elegant writer) generating a new animal. But I have long regretted that I truckled to public opinion & used Pentateuchal term of creation, by which I really meant “appeared” by some wholly unknown process.—It is mere rubbish thinking, at present, of origin of life; one might as well think of origin of matter».

Three weeks later, Darwin ( 1863 ) finished a sharp response to Owen’s criticism, and submitted it to the Athenæum, which promptly published it [ www.darwinproject.ac.uk/ ] [Letter 4108]

«Down, Bromley, Kent, April 18.

I hope that you will permit me to add a few remarks on Heterogeny, as the old doctrine of spontaneous generation is now called, to those given by Dr. Carpenter, who, however, is probably better fitted to discuss the question than any other man in England. Your reviewer believes that certain lowly organized animals have been generated spontaneously—that is, without pre-existing parents—during each geological period in slimy ooze. A mass of mud with matter decaying and undergoing complex chemical changes is a fine hiding-place for obscurity of ideas. But let us face the problem boldly. He who believes that organic beings have been produced during each geological period from dead matter must believe that the first being thus arose. There must have been a time when inorganic elements alone existed on our planet: let any assumptions be made, such as that the reeking atmosphere was charged with carbonic acid, nitrogenized compounds, phosphorus, &c. Now is there a fact, or a shadow of a fact, supporting the belief that these elements, without the presence of any organic compounds, and acted on only by known forces, could produce a living creature? At present it is to us a result absolutely inconceivable. Your reviewer sneers with justice at my use of the “Pentateuchal terms”, “of one primordial form into which life was first breathed”: in a purely scientific work I ought perhaps not to have used such terms; but they well serve to confess that our ignorance is as profound on the origin of life as on the origin of force or matter. Your reviewer thinks that the weakness of my theory is demonstrated because existing Foraminifera are identical with those which lived at a very remote epoch. Most naturalists look at this fact as the simple result of descent by ordinary reproduction; in no way different, as Dr. Carpenter remarks, except in the line of descent being longer, from that of the many shells common to the middle Tertiary and existing periods.

The view given by me on the origin or derivation of species, whatever its weaknesses may be, connects (as has been candidly admitted by some of its opponents, such as Pictet, Bronn, &c.) by an intelligible thread of reasoning a multitude of facts: such as the formation of domestic races by man’s selection,—the classification and affinities of all organic beings,—the innumerable gradations in structure and instincts,—the similarity of pattern in the hand, wing or paddle of animals of the same great class,—the existence of organs become rudimentary by disuse,—the similarity of an embryonic reptile, bird and mammal, with the retention of traces of an apparatus fitted for aquatic respiration; the retention in the young calf of incisor teeth in the upper jaw, &c.,—the distribution of animals and plants, and their mutual affinities within the same region,—their general geological succession, and the close relationship of the fossils in closely consecutive formations and within the same country; extinct marsupials having preceded living marsupials in Australia, and armadillo-like animals having preceded and generated armadilloes in South America,—and many other phenomena, such as the gradual extinction of old forms and their gradual replacement by new forms better fitted for their new conditions in the struggle for life. When the advocate of Heterogeny can thus connect large classes of facts, and not until then, he will have respectful and patient listeners.

Dr. Carpenter seems to think that the fact of Foraminifera not having advanced in organization from an extremely remote epoch to the present day is a strong objection to the views maintained by me. But this objection is grounded on the belief—the prevalence of which seems due to the well-known doctrine of Lamarck—that there is some necessary law of advancement, against which view I have often protested. Animals may even become degraded, if their simplified structure remains well fitted for their habits of life, as we see in certain parasitic crustaceans. I have attempted to show (Origin, 3rd edit. p. 135) that lowly-organized animals are best fitted for humble places in the economy of nature; that an infusorial animalcule or an intestinal worm, for instance, would not be benefited by acquiring a highly complex structure. Therefore, it does not seem to me an objection of any force that certain groups of animals, such as the Foraminifera, have not advanced in organization. Why certain whole classes, or certain numbers of a class, have advanced and others have not, we cannot even conjecture. But as we do not know under what forms or how life originated in this world, it would be rash to assert that even such lowly endowed animals as the Foraminifera, with their beautiful shells as figured by Dr. Carpenter, have not in any degree advanced in organization. So little do we know of the conditions of life all around us, that we cannot say why one native weed or insect swarms in numbers, and another closely allied weed or insect is rare. Is it then possible that we should understand why one group of beings has risen in the scale of life during the long lapse of time, and another group has remained stationary? Sir C. Lyell, who has given so excellent a discussion on species in his great work on the ‘Antiquity of Man’, has advanced a somewhat analogous objection, namely, that the mammals, such as seals or bats, which alone have been enabled to reach oceanic islands, have not been developed into various terrestrial forms, fitted to fill the unoccupied places in their new island-homes; but Sir Charles has partly answered his own objection. Certainly I never anticipated that I should have had to encounter objections on the score that organic beings have not undergone a greater amount of change than that stamped in plain letters on almost every line of their structure. I cannot here resist expressing my satisfaction that Sir Charles Lyell, to whom I have for so many years looked up as my master in geology, has said (2nd edit. p. 469):—“Yet we ought by no means to undervalue the importance of the step which will have been made, should it hereafter become the generally received opinion of men of science (as I fully expect it will) that the past changes of the organic world have been brought about by the subordinate agency of such causes as Variation and Natural Selection”. The whole subject of the gradual modification of species is only now opening out. There surely is a grand future for Natural History. Even the vital force may hereafter come within the grasp of modern science, its correlations with other forces have already been ably indicated by Dr. Carpenter in the Philosophical Transactions ; but the nature of life will not be seized on by assuming that Foraminifera are periodically generated from slime or ooze.

Charles Darwin»

It is somewhat surprising to see that historians of science have largely overlooked Darwin’s extensive response, which is the direct antecedent to the “warm little pond” letter that he sent in 1871 to Hooker. In any case, Darwin had enjoyed so much preparing his rebuttal of Owen, that two days later after mailing it to the Athenæum he wrote to Asa Gray that [ www.darwinproject.ac.uk/ ] [Letter 4110],

«[…] We have had lately sharp sparring in the Athenæum. Did you see the article on Heterogeny or Spontaneous generation, written I believe, certainly by Owen!! it was in Review on Carpenter, who seems to have been sillily vexed at Owen calling me Carpenter’s master; it was like his clever malignity. Under the cloak of a fling at Heterogeny I have sent a letter to Athenæum in defence of myself, & I take sly advantage to quote Lyells amended verdict on the Origin.—I suppose my letter will appear next week: it is no great thing. […]»

The Story Behind a Warm Little Pond

It is certainly amusing to see that Darwin did not refrain, both in private and in public, from the use of irony, as shown by the extensive letter he sent to the Athenæum. He clearly kept in the back of his mind his assumption that life could evolve from a «…reeking atmosphere was charged with carbonic acid, nitrogenized compounds, phosphorus, &c.». Eight years later he mailed to Hooker the famous letter in which the idea of a “warm little pond” was included. Darwin’s “big if”, however, is a cautious reminder that he was keenly aware of the lack of evidence for this possibility. The now famous letter was mailed to Hooker on February 1st, 1871,

«Down,

Beckenham, Kent, S.E.

My dear Hooker,

I return the pamphlets, which I have been very glad to read.—It will be a curious discovery if Mr. Lowe’s observation that boiling does not kill certain molds is proved true; but then how on earth is the absence of all living things in Pasteur’s experiments to be accounted for?—I am always delighted to see a word in favour of Pangenesis, which some day, I believe, will have a resurrection. Mr. Dyer’s paper strikes [?] me as a very able Spencieran production.

It is often said that all the conditions for the first production of a living organism are now present, which could ever have been present. But if (and oh what a big if) we could conceive in some warm little pond with all sorts of ammonia and phosphoric salts,—light, heat, electricity &c. present, that a protein compound was chemically formed, ready to undergo still more complex changes, at the present day such matter w d be instantly devoured, or absorbed, which would not have been the case before living creatures were formed.

Henrietta makes hardly any progress, and God knows when she will be well.

I enjoyed much the visit of you four gentlemen, i.e., after the Saturday night, when I thought I was quite done for.

Yours affect y

C. Darwin»

His son Francis Darwin included part of this now famous letter as a footnote in the 3rd volume of Life and Letters (Darwin 1887 , Vol 3:168–169). In 1969 Melvin Calvin included the letter (both the transcription and the facsimile) in his book on chemical evolution (Calvin 1969 ), calling it to the attention of the origins-of-life community.

Darwin’s letter summarizes in a nutshell his ideas on the emergence of life, and provides insights on the views on the chemical nature of the basic biological processes that were becoming prevalent in scientific circles. Although Friedrich Miescher had discovered nucleic acids (he called them nuclein) in 1869 (Dahm 2005 ), the deciphering of their central role in genetic processes would remain unknown for almost another century. In contrast, the roles played by proteins in manifold biological processes had been established. Equally significant, by the time Darwin wrote his letter major advances had been made in the understanding of the material basis of life, which for a long time had been considered to be fundamentally different from inorganic compounds. Although in 1827 Jöns Jacob Berzelius, probably the most influential chemist of his day, had written that “art cannot combine the elements of inorganic matter in the manner of living nature”, 1 year later his friend and former student Friedrich Wöhler demonstrated that urea could be formed in high yield by heating ammonium cyanate “without the need of an animal kidney”.

Although Darwin had developed a strong interest in chemistry as a youngster, it is not known if he was aware of the synthesis of alanine achieved by Adolf Strecker in 1850. In the absence of any real corroborative evidence, it is impossible to guess what Darwin thought about the nature of the first living beings. In any case, Darwin’s remarks should not be read to imply that he was thinking in terms of prebiotic chemistry, but rather that he recognized that the chemical gap separating organisms from the non-living was not insurmountable.

Fossils in Meteorites: the Meeting that Never was

In his recently published Charles Darwin Shorter Publications 1829–1883 , van Wyhe ( 2009 ) has included a curious item published in 1881 in Science under the title Mr. Darwin on Dr. Hahn’s discovery of fossil organisms in meteorites . The short note describes an exchange between Charles Darwin and Otto Hahn, an amateur geologist who claimed in 1880 that he had discovered remains of extraterrestrial sponges, corals and plants in the Knyahinya meteorite that fell in Hungary on June 6, 1866 (van Wyhe 2009 ). The complete text states that,

«Dr. Hahn’s discovery, of which an elaborate account was given in No. 50 of SCIENCE has stirred up a lively discussion of this highly interesting subject. Dr. Hahn has taken steps to enable Prof. von Quenstedt, the renowned Tübingen geologist, and all others who expressed the desire to examine his microscopic preparations. It is understood that all those who have availed themselves of the opportunity thus offered have become convinced of the genuineness of Dr. Hahn’s discovery.

It is very interesting to note the position taken by the greatest of living evolutionists in this controversy, if it can still be called such. Charles Darwin, on receipt of Dr. Hahn’s work, wrote to him: “… It seems to be very difficult to doubt that your photographs exhibit organic structure...” and furthermore: “... your discovery is certainly one of the most important”.

Not content with the mere presentation of his work, Dr. Hahn visited the veteran zoologist and brought his preparations to him for inspection.

No sooner had Mr. Darwin peered through the microscope on one of the finest specimens when he started up from his seat and exclaimed: “Almighty God! what a wonderful discovery! Wonderful!” And after a pause of silent reflection he added: “Now reaches life down!” The latter remark no doubt refers to the proof furnished by Dr. Hahn’s discovery that organisms can reach our planet from celestial space. It is an acknowledgment of the relief Mr. Darwin must have felt in not being forced to a belief in a primeval “ generatio equivoca ”.

As was suggested in the paper referred to, “the Richter-Thomson [“cosmozoa/panspermia”]hypothesis of the origin of life on the earth has become a tangible reality!”»

Hahn’s books are now at Down House but have no marginalia (van Wyhe 2009 ). Moreover, in the Darwin Archive (DAR251, calendar 12929f) there is draft of a letter that Darwin sent on December 20, 1880 to Hahn, in which he wrote that “If you succeed in convincing several judges as trustworthy as Professor Quenstedt, you will certainly have made one of the most remarkable discoveries ever recorded.” However, there is no evidence that Hahn actually visited Down House, and this may be apocryphal. As described by van Wyhe ( 2009 ) “no evidence for the interview has been found in the Stadtsarchiv Reutlingen, Germany, in the Darwin Archive or in the correspondence”. Thomas George Bonney (1833–1923), professor of geology at University College, London, wrote to Francis Darwin [January? 1882] (Cambridge University Library MSS.DAR.160:247) asking if the report in Science was true. Bonney intended to insert a rebuttal for the claim in a review he was writing (unidentified) on an allied subject. Darwin replied in a letter to Bonney (now lost). Bonney later thanked Darwin in a 5 February 1882 letter (Cambridge University Library MSS.DAR.160:246 and 248) for denying the truth of the claim that he accepted the organic nature of the microscopic structures and remarked that “Hahn could not distinguish between mineral and organic structures”. In fact, it is likely that Hahn’s visit never took place.

It should be noted that because of William Thomson’s (later Lord Kelvin) claim that the Earth’s age was too young to be compatible with Darwin’s theory of evolution, and Pasteur’s work debunking spontaneous generation, the “cosmozoa/panspermia” theory was championed by many noted scientists during Darwin’s time, although apparently he never commented on the concept. The idea that there were fossils present in some meteorites was embraced by parts of the scientific community although others questioned the validity of these claims. As Hooker wrote, “[t]he notion of introducing life on Meteors is astounding and very unphilosophical […]. For my part, I would as soon believe in the Phoenix as in the meteoritic import of life” (Hooker 1871, in Crowe 1986 ).

Final Remarks

Although Darwin had stated in The Origin of Species that “all the organic beings which have ever lived on this Earth may be descended from some primordial form”, he was keenly aware that there was no explanation of how such an ancestral entity had first evolved. Darwin’s theory was based, among other lines of evidence, on observations of living and fossil organisms, but for him the fossil record stopped at rocks that we know now correspond to the end of the Precambrian. Moreover, he did not view microbes, which are gorgeously absent from his work, as evolutionary predecessors of animals and plants (Lazcano 2002 ). Charles Darwin’s self-imposed task was the understanding of the evolutionary processes that underlie biological diversity, a task that epistemologically can be undertaken even if it provides no explanation of the origin of life itself. As he wrote in 1839 in his Fourth Notebook (de Beer 1960 :180), «My theory leaves quite untouched the question of spontaneous generation».

Darwin included few statements on the origin of life in his books. As underlined by Aulie ( 1970 ) this is what he wanted to make public. Over and over again he carefully emphasized the lack of evidence on the possibility of spontaneous generation. For instance, in the 6th edition of The Origin of Species (1871) he stated «…it may be objected that if all organic beings thus tend to rise in the scale, how is it that throughout the world multitude of the lowest forms still exist [...]. Lamarck, who believed in an innate and inevitable tendency towards perfection in all organic beings, seems to have felt this difficulty so strongly, that he was led to suppose that new and simple forms were continually being produced by spontaneous generation. Science has not as yet proved the truth of this belief, whatever the future may reveal» (Peckham 1959 :223).

Not surprisingly, the idea that living organisms were the historical outcome of gradual transformation of lifeless matter became widespread soon after the publication of Darwin’s The Origin of Species . However, Darwin was not a prophet who predicted in his 1871 letter to Hooker the experiments on abiotic chemical synthesis carried out since the first 1953 Miller-Urey experiment. Although he insisted over and over again that there was no evidence of how the first organisms may have first appeared, he was firmly convinced it was the outcome of a natural process that had to be approached from a secular framework.

It is true, as Lady Antonia Fraser once wrote, that hindsight can make bad history. However, Darwin’s reluctance to discuss the origin of life does not imply that he advocated mystical explanations. As shown by the pages that he would later excise from his Second Notebook, as early as 1837 he was convinced that “The intimate relation of Life with laws of chemical combination, & the universality of latter render spontaneous generation not improbable.” (de Beer et al. 1967 ).

This early statement is consistent with many other lines of evidence demonstrating that Darwin took for granted a natural origin of life. However, his ideas on how it may have happened must remain forever in the domain of historical speculation. In a letter he sent in February 28, 1882 to D. Mackintosh (Letter 13711, Cambridge University Library, DAR.146:335), he included an indirect reference to Wöhler’s synthesis of urea and added that

«Though no evidence worth anything has as yet, in my opinion, been advanced in favour of a living being, being developed from inorganic matter, yet I cannot avoid believing the possibility of this will be proved some day in accordance with the law of continuity. I remember the time, above 50 years ago, when it was said that no substance found in a living plant or animal could be produced without the aid of vital forces. As far as external form is concerned, Eozoon shows how difficult it is to distinguish between organised and inorganised bodies. If it is ever found that life can originate on this world, the vital phenomena will come under some general law of nature. Whether the existence of a conscious God can be proved from the existence of the so called laws of nature (i. e. fixed sequence of events) is a perplexing subject, on which I have often thought, but cannot see my way clearly...».

Over and over again Darwin insisted that the issue of spontaneous generation was intractable by the science of his time. As he wrote on November 21, 1866 to Julius Viktor Carus [ www.darwinproject.ac.uk/ ] [Letter 5282], who was preparing a new edition of The Origin of Species , that,

«My dear Sir

[…] I see that I have forgotten to say that you have my fullest consent to append any discussion which you may think fit to the new edition. As for myself I cannot believe in spontaneous generation & though I expect that at some future time the principle of life will be rendered intelligible, at present it seems to me beyond the confines of science».

He was to maintain the same attitude for many years to come, as shown by the letter mailed on March 28, 1882, near the end of his life, to George Charles Wallich (de Beer 1959 ). In it Darwin wrote that,

«My dear Sir,

You expressed quite correctly my views where you say that I had intentionally left the question of the Origin of Life uncanvassed as being altogether ultra vires in the present state of our knowledge, & that I dealt only with the manner of succession. I have met with no evidence that seems in the least trustworthy, in favour of the so-called Spontaneous generation. I believe that I have somewhere said (but cannot find the passage) that the principle of continuity renders it probable that the principle of life will hereafter be shown to be a part, or consequence of some general law; but this is only conjecture and not science. I know nothing about the Protista, and shall be very glad to read your Lecture when it is published, if you will be so kind as to send me a copy.

I remain, my dear Sir,

Yours very faithfully

Darwin’s letter to Wallich expresses once more his reaction against the idea of life emerging from the decomposition of organic compounds. It is interesting, however, to recall a letter he sent on August 28, 1872 to Wallace, were Darwin wrote that ([Letter 8488],

«[...] I should like to live to see Archebiosis proved true, for it would be a discovery of transcendent importance; or, if false, I should like to see it disproved, and the facts otherwise explained; but I shall not live to see all this». Nor will we.

Acknowledgements

The assistance of Mr. Adam Perkins, archivist of the Darwin Archive at Cambridge University Library and Mme. Judith Magee, Collection Development Manager of the Natural History Museum Library is gratefully acknowledged. The authors also wish to thank Paola Marco for her help to localize some of Darwin’s letters. The work reported here has been greatly facilitated by the documents available at The Darwin Correspondence Project ( http://www.darwinproject.ac.uk/ , Jim Secord, director) and The Complete Work of Charles Darwin Online ( http://darwin-online.org.uk/ , John van Wyhe, director). J.P. acknowledges the financial support by grants BFU2006-01951/BMC from the Spanish Ministry of Science and Innovation and FP7-KBBE-2007-212894 (TARPOL project, European Union). The support of the Institut Pasteur-Fondazione Cenci Bolognetti (Universita di Roma, La Sapienza) and the generous hospitality of Professor Ernesto di Mauro (Universita di Roma, La Sapienza) to A.L. are gratefully acknowledged.

Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.

Invited Paper

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• Calvin M (1969) Chemical evolution: Molecular evolution towards the origin of living systems on the Earth and elsewhere. Oxford University Press, New York
• Crowe MJ (1986) The extraterrestrial life debate 1750–1900: The idea of a plurality of worlds from Kant to Lowell. Cambridge University Press, Cambridge
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• De Beer G (1959) Some unpublished letters of Charles Darwin. Notes Rec R Soc Lond 14:12–66
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• de Beer G, Rowlands MJ, Skramovsky BM (eds) (1967) Darwin’s notebooks on transmutation of species. Part VI. Pages excised by Darwin. Bull Brit Mus (Nat Hist) Hist Ser 3:129–176 [ PubMed ]
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Charles Darwin's Finches

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Charles Darwin is known as the father of evolution . When he was a young man, Darwin set out on a voyage on the HMS Beagle . The ship sailed from England in late December of 1831 with Charles Darwin aboard as the crew's naturalist. The voyage was to take the ship around South America with many stops along the way. It was Darwin's job to study the local flora and fauna, collecting samples and making observations he could take back to Europe with him of such a diverse and tropical location.

The crew made it to South America in a few short months, after a brief stop in the Canary Islands. Darwin spent most of his time on land collecting data. They stayed for more than three years on the continent of South America before venturing on to other locations. The next celebrated stop for the HMS Beagle was the Galapagos Islands off the coast of Ecuador .

Galapagos Islands

Charles Darwin and the rest of the HMS Beagle crew spent only five weeks in the Galapagos Islands, but the research performed there and the species Darwin brought back to England were instrumental in the formation of a core part of the original theory of evolution and Darwin's ideas on natural selection which he published in his first book . Darwin studied the geology of the region along with giant tortoises that were indigenous to the area.

Perhaps the best known of Darwin's species he collected while on the Galapagos Islands were what are now called "Darwin's Finches". In reality, these birds are not really part of the finch family and are thought to probably actually be some sort of blackbird or mockingbird. However, Darwin was not very familiar with birds, so he killed and preserved the specimens to take back to England with him where he could collaborate with an ornithologist.

Finches and Evolution

The HMS Beagle continued to sail on to as far away lands as New Zealand before returning to England in 1836. It was back in Europe when he enlisted in the help of John Gould, a celebrated ornithologist in England. Gould was surprised to see the differences in the beaks of the birds and identified the 14 different specimens as actual different species - 12 of which were brand new species. He had not seen these species anywhere else before and concluded they were unique to the Galapagos Islands. The other, similar, birds Darwin had brought back from the South American mainland were much more common but different than the new Galapagos species.

Charles Darwin did not come up with the Theory of Evolution on this voyage. As a matter of fact, his grandfather Erasmus Darwin had already instilled the idea that species change through time in Charles. However, the Galapagos finches helped Darwin solidify his idea of natural selection . The favorable adaptations of Darwin's Finches' beaks were selected for over generations until they all branched out to make new species .

These birds, although nearly identical in all other ways to mainland finches, had different beaks. Their beaks had adapted to the type of food they ate in order to fill different niches on the Galapagos Islands. Their isolation on the islands over long periods of time made them undergo speciation. Charles Darwin then began to disregard the previous thoughts on evolution put forth by Jean Baptiste Lamarck who claimed species spontaneously generated from nothingness.

Darwin wrote about his travels in the book The Voyage of the Beagle and fully explored the information he gained from the Galapagos Finches in his most famous book On the Origin of Species . It was in that publication that he first discussed how species changed over time, including divergent evolution, or adaptive radiation, of the Galapagos finches.

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• Artificial Selection: Breeding for Desirable Traits
• The Legacy of Darwin's "On the Origin of Species"
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Darwin in America

The evolution debate in the united states.

A lmost 160 years after Charles Darwin publicized his groundbreaking theory on the development of life, Americans are still arguing about evolution. In spite of the fact that evolutionary theory is accepted by all but a small number of scientists, it continues to be rejected by many Americans. In fact, about one-in-five U.S. adults reject the basic idea that life on Earth has evolved at all. And roughly half of the U.S. adult population accepts evolutionary theory , but only as an instrument of God’s will.

Most biologists and other scientists contend that evolutionary theory convincingly explains the origins and development of life on Earth. Moreover, they say, a scientific theory is not a hunch or a guess, but is instead an established explanation for a natural phenomenon, like gravity, that has repeatedly been tested and refined through observation and experimentation.

So if evolution is as established in the scientific community as the theory of gravity, why are people still arguing about it more than century and a half after Darwin proposed it? The answer lies, in large part, in the theological implications of evolutionary thinking. For many religious people, the Darwinian view of life – a panorama of brutal struggle and constant change – conflicts with both the biblical creation story and the Judeo-Christian concept of an active, loving God who intervenes in human events. (See “ Religious Groups’ Views on Evolution .”)

This basic concern with evolutionary theory has helped drive the decadeslong opposition to teaching it in public schools. Even over the last 15 years, educators, scientists, parents, religious leaders and others in more than a dozen states have engaged in public battles in school boards, legislatures and courts over how school curricula should handle evolution. The issue was even discussed and debated during the runups to the 2000 and 2008 presidential elections . This battle has ebbed in recent years, but it has not completely died out.

Outside the classroom, much of the opposition to evolution has involved its broader social implications and the belief that it can be understood in ways that are socially and politically dangerous. For instance, some social conservatives charge that evolutionary theory serves to strengthen broader arguments that justify practices they vehemently oppose, such as abortion and euthanasia. Evolutionary theory also plays a role in arguments in favor of transhumanism and other efforts to enhance human abilities and extend the human lifespan . Still other evolution opponents say that well-known advocates for atheism, such as Richard Dawkins, view evolutionary theory not just as proof of the folly of religious faith, but also as a justification for various types of discrimination against religion and religious people.

A look back at American history shows that, in many ways, questions about evolution have long served as proxies in larger debates about religious, ethical and social norms. From efforts on the part of some churches in the 19th and early 20th centuries to advance a more liberal form of Christianity, to the more recent push and pull over the roles of religion and science in the public square, attitudes toward evolution have often been used as a fulcrum by one side or the other to try to advance their cause.

Darwin comes to America

In formulating his theory of evolution through natural selection, Charles Darwin did not set out to create a public controversy. In fact, his concerns over how his ideas would be received by the broader public led him to wait more than 20 years to publicize them. He might never have done so if another British naturalist, Alfred Russel Wallace, had not in 1858 independently come up with a very similar theory. At that point, Darwin, who had already shared his conclusions with a small number of fellow scientists, finally revealed his long-held ideas about evolution and natural selection to a wider audience.

Darwin built his theory on four basic premises. First, he argued, each animal is not an exact replica of its parents, but is different in subtle ways. Second, he said, although these differences in each generation are random, some of them convey distinct advantages to an animal, giving it a much greater chance to survive and breed. Over time, this beneficial variation spreads to the rest of the species, because those with the advantage are more likely than those without it to stay alive and reproduce. And, finally, over longer periods of time, cumulative changes produce new species, all of which share a common ancestor. (For more on this, see “ Darwin and His Theory of Evolution .”)

In November 1859, Darwin published “On the Origin of Species by Means of Natural Selection,” which laid out his theory in detail. The book became an instant bestseller and, as Darwin had feared, set off a firestorm of controversy in his native Britain. While many scientists defended Darwin, religious leaders and others immediately rejected his theory, not only because it directly contradicted the creation story in the biblical book of Genesis, but also because – on a broader level – it implied that life had developed due to natural processes rather than as the creation of a loving God.

In the United States, which was on the verge of the Civil War, the publication of “Origin” went largely unnoticed. By the 1870s, American religious leaders and thinkers had begun to consider the theological implications of Darwin’s theory. Still, the issue didn’t filter down to the wider American public until the end of the 19th century, when many popular Christian authors and speakers, including the famed Chicago evangelist and missionary Dwight L. Moody, began to inveigh against Darwinism as a threat to biblical truth and public morality.

At the same time, other dramatic shifts were taking place in the country’s religious landscape. From the 1890s to the 1930s, the major American Protestant denominations gradually split into two camps: modernist, or theologically liberal Protestantism (what would become mainline Protestantism); and evangelical, or otherwise theologically conservative, Protestantism.

This schism owed to numerous cultural and intellectual developments of the era, including, but not limited to, the advent of new scientific thinking. Theologians and others also grappled with new questions about the historical accuracy of biblical accounts, as well as a host of provocative and controversial new ideas from such thinkers as Karl Marx and Sigmund Freud about both the individual and society. Modernist Protestants sought to integrate these new theories and ideas, including evolution, into their religious doctrine, while more conservative Protestants resisted them.

By the early 1920s, evolution had become perhaps the most important wedge issue in this Protestant divide, in part because the debate had taken on a pedagogical dimension, with students throughout the nation now studying Darwin’s ideas in biology classes. The issue became a mainstay for Protestant evangelists, including Billy Sunday, the most popular preacher of this era. “I don’t believe the old bastard theory of evolution,” he famously exclaimed during a 1925 revival meeting. But it was William Jennings Bryan, a man of politics, not the cloth, who ultimately became the leader of a full-fledged national crusade against evolution.

Bryan, a populist orator and devout evangelical Protestant who had thrice run unsuccessfully for president, believed that teaching of evolution in the nation’s schools would ensure that whole generations would grow up believing that the Bible was no more than “a collection of myths,” and would undermine the country’s Christian faith in favor of the doctrine of “survival of the fittest.”

Bryan’s fear of social Darwinism was not entirely unfounded. Evolutionary thinking had helped birth the eugenics movement, which maintained that one could breed improved human beings in the same way that farmers breed better sheep and cattle. Eugenics led to now-discredited theories of race and class superiority that helped inspire Nazi ideology ; in America, some used social Darwinism to argue in favor of restricting immigration (particularly from Southern and Eastern Europe) or to enact state laws requiring sterilization to stop “mental deficients” from having children.

Many who favored the teaching of evolution in public schools did not support eugenics, but simply wanted students to be exposed to the most current scientific thinking. For others, like supporters of the newly formed American Civil Liberties Union, teaching evolution was an issue of freedom of speech as well as a matter of maintaining a separation of church and state. And still others, like famed lawyer Clarence Darrow, saw the battle over evolution as a proxy for a wider cultural conflict between what they saw as progress and modernity on the one side, and religious superstition and backwardness on the other.

Scopes and its aftermath

At the urging of Bryan and evangelical Christian leaders, evolution opponents tried to ban the teaching of Darwin’s theory in a number of states. Although early legislative efforts failed, evolution opponents won a victory in 1925 when the Tennessee Legislature overwhelmingly approved legislation making it a crime to teach “any theory that denies the story of the Divine Creation of man as taught in the Bible.” Soon after the Tennessee law was enacted, the ACLU offered to defend any science teacher in the state who was willing to break it. John Scopes, a teacher in the small, rural town of Dayton, Tennessee, agreed to take up the ACLU’s offer.

The subsequent trial popularly referred to as the Scopes “monkey” trial, was one of the first true media trials of the modern era, covered in hundreds of newspapers and broadcast live on the radio. Defending Scopes was Darrow, then the most famous lawyer in the country. And joining state prosecutors was Bryan. From the start, both sides seemed to agree that the case was being tried more in the court of public opinion than in a court of law.

As the trial progressed, it seemed increasingly clear that Darrow’s hope of spurring public debate over the merits of teaching evolution was being stymied by state prosecutors. But then Darrow made the highly unorthodox request of calling Bryan to the witness stand. Although the politician was under no obligation to testify, he acceded to Darrow’s invitation.

With Bryan on the stand, Darrow proceeded to ask a series of detailed questions about biblical events that could be seen as inconsistent, unreal or both. For instance, Darrow asked, how could there be morning and evening during the first three days of biblical creation if the sun was not formed until the fourth? Bryan responded to this and similar questions in different ways. Often, he defended the biblical account in question as the literal truth. On other occasions, however, he admitted that parts of the Bible might need to be interpreted in order to be fully understood.

Scopes was convicted of violating the anti-evolution law and fined, although his conviction was later overturned by the Tennessee Supreme Court on a technicality. But the verdict was largely irrelevant to the broader debate. The trial, particularly Darrow’s questioning of Bryan, created a tremendous amount of positive publicity for the pro-evolution camp, especially in northern urban areas, where the media and cultural elites were sympathetic toward Scopes and his defense.

At the same time, this post-Scopes momentum did not destroy the anti-evolution movement. Indeed, in the years immediately following Scopes, the Mississippi and Arkansas state legislatures enacted bills similar to Tennessee’s. Other states, particularly in the South and Midwest, passed resolutions condemning the inclusion of material on evolution in biology textbooks. These actions, along with a patchwork of restrictions from local school boards, prompted most publishers to remove references to Darwin from their science textbooks.

Efforts to make evolution the standard in all biology classes stalled, due largely to the fact that the government prohibition on religious establishment or favoritism, found in the establishment clause of the First Amendment to the U.S. Constitution, applied at the time only to federal and not state actions. State governments could set their own policies on church-state issues. Only in 1947, with the Supreme Court’s decision in Everson v. Board of Education, did the constitutional prohibition on religious establishment begin to apply to state as well as federal actions. Evolution proponents also received a boost a decade after Everson, in 1957, when the Soviet launch of the first satellite, Sputnik I, prompted the United States to make science education a national priority.

Meanwhile, beginning in the late 1960s, the U.S. Supreme Court issued a number of important decisions that imposed severe restrictions on state governments that opposed the teaching of evolution. In 1968, in Epperson v. Arkansas, the high court unanimously struck down as unconstitutional an Arkansas law banning the teaching of evolution in public schools. Specifically, the justices said, the law violated the First Amendment’s establishment clause because it sought to prevent students from learning a particular viewpoint antithetical to conservative Christianity, and thus promoted religion.

Almost 20 years after Epperson, the court issued another key ruling, this time involving the teaching of “creation science” in public schools. Proponents of creation science contend that the weight of scientific evidence supports the creation story as described in the biblical book of Genesis, with the formation of Earth and the development of life occurring in six 24-hour days. The presence of fossils and evidence of significant geological change are attributed to the catastrophic flood described in the eighth chapter of Genesis.

In Edwards v. Aguillard (1987), the high court struck down a Louisiana law requiring public schools to teach “creation science” alongside evolution, ruling (as in Epperson) that the statute violated the establishment clause because its aim was to promote religion. (For more on the legal aspects of the evolution debate, see “ The Social and Legal Dimensions of the Evolution Debate in the U.S. ”)

Partly due to these and other court decisions, opposition to teaching evolution itself evolved, with opponents changing their goals and tactics. In the first decade of the 21st century, for instance, some local and state school boards mandated the teaching of what they argued were scientific alternatives to evolution – notably the concept of “intelligent design,” which posits that life is too complex to have developed without the intervention of an outside, possibly divine, force. While rejected by most scientists as creationism cloaked in scientific language, supporters of intelligent design cite what they call “irreducibly complex” systems (such as the eye or the process by which blood clots) as proof that Darwinian evolution is not an adequate explanation for the development of life.

But efforts to inject intelligent design into public school science curricula met the same fate as creation science had decades earlier. Once again, courts ruled that intelligent design is a religious argument, not science, and thus couldn’t be taught in public schools. Other efforts to require schools to teach critiques of evolution or to mandate that students listen to or read evolution disclaimers also were struck down.

In the years following these court decisions, there have been new efforts in Texas, Tennessee, Kansas and other states to challenge the presence of evolutionary theory in public school science curricula. For instance, in 2017, the South Dakota Senate passed legislation that would allow teachers in the state’s public schools to present students with both the strengths and weaknesses of scientific information. The measure, which critics claimed was clearly aimed at critiquing evolution, ultimately stalled in the state’s House of Representatives. And in 2018, an internal review at the Arizona State Board of Education led to an unsuccessful effort to dilute references to evolution in the state’s science standards.

For more information about how Pew Research Center asks the U.S. public about their views on evolution, see “ The Evolution of Pew Research Center’s Survey Questions About the Origins and Development of Life on Earth ” and “ How highly religious Americans view evolution depends on how they’re asked about it .”

Title photo: Famed attorney Clarence Darrow makes a point at the “Scopes Monkey Trial” in 1925. Darrow defended teacher John Scopes, who had run afoul of Tennessee’s law against teaching evolution in public schools. (Bettmann Archive/Getty Images)

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RNA's hidden potential: New study unveils its role in early life and future bioengineering

Study sheds light on the molecular evolution of rna and its potential applications in nanobiotechnology..

The beginning of life on Earth and its evolution over billions of years continue to intrigue researchers worldwide. The central dogma or the directional flow of genetic information from a deoxyribose nucleic acid (DNA) template to a ribose nucleic acid (RNA) transcript, and finally into a functional protein, is fundamental to cellular structure and functions. DNA functions as the blueprint of the cell and carries genetic information required for the synthesis of functional proteins. Conversely, proteins are required for the synthesis of DNA. Therefore, whether DNA emerged first or protein, continues to remain a matter of debate.

This molecular version of the "chicken and egg" question led to the proposition of an "RNA World." RNAs in the form of 'ribozymes' or RNA enzymes carry genetic information similar to DNA and also possess catalytic functions like proteins. The discovery of ribozymes further fueled the RNA World hypothesis where RNA served dual functions of "genetic information storage" and "catalysis," facilitating primitive life activities solely by RNA. While modern ribosomes are a complex of RNAs and proteins, ribozymes during early evolutionary stages may have been pieced together through the assembly of individual functional RNA units.

To test this hypothesis, Professor Koji Tamura, along with his team of researchers at the Department of Biological Science and Technology, Tokyo University of Science, conducted a series of experiments to decode the assembly of functional ribozymes. For this, they designed an artificial ribozyme, R3C ligase, to investigate how individual RNA units come together to form a functional structure. Giving further insight into their work published on 17 April 2024, in Life , Prof. Tamura states, "The R3C ligase is a ribozyme that catalyzes the formation of a 3',5'-phosphodiester linkage between two RNA molecules. We modified the structure by adding specific domains that can interact with various effectors."

Within ribosomes, which are the site of protein synthesis, RNA units assemble to function as Peptidyl Transferase Center (PTC) in a way such that they form a scaffold for the recruitment of amino acids (individual components of a peptide/protein) attached to tRNAs. This is an important insight into the evolutionary history of protein synthesis systems, but it is not sufficient to trace the evolutionary pathway based on the RNA World hypothesis.

To explore if the elongation of RNA, achieved by linking individual RNA units together, is regulated allosterically, the researchers altered the structure of the R3C ligase. They did this by incorporating short RNA sequences that bind adenosine triphosphate (ATP), a vital energy carrier molecule in cells, into the ribozyme. The team noted that R3C ligase activity was dependent on the concentration of ATP, with higher activity observed at higher concentrations of ATP. Further, an increase in the melting temperature (T m value) indicated that the binding of ATP to R3C ligase stabilized the structure, which likely influenced its ligase activity.

Similarly, on fusing an L-histidine-binding RNA sequence to the ribozyme, they noted an increase in ligase activity at increasing concentrations of histidine (a key amino acid). Notably, the increase in activity was specific to increasing concentrations of ATP or histidine; no changes were observed in response to other nucleotide triphosphates or amino acids. These findings suggest that ATP and histidine act as effector molecules that trigger structural conformational changes in the ribozyme, which further influence enzyme stability and activity.

ATP is the central energy carrier of the cell which supports numerous molecular processes, while, histidine is the most common amino acid found in the active site of enzymes, and maintains their acid-base chemistry. Given, the important roles of ATP and histidine in RNA interactions and molecular functions, these results provide novel insights into the role of RNA in early evolution, including the origin of the genetic code. Furthermore, engineered ribozymes such as the one developed in this study hold significant promise in a myriad of applications including targeted drug delivery, therapeutics, nano-biosensors, enzyme engineering, and synthesis of novel enzymes with uses in various industrial processes.

Overall, this study can offer insights into how the transition from the RNA World to the modern "DNA/Protein World" occurred. A fundamental understanding of the RNA World in turn, can enhance their use in real-life applications.

"This study will lead to the elucidation of the process of 'allostericity-based acquisition of function and cooperativity' in RNA evolution. The RNA-RNA interactions, RNA-amino acid interactions, and allostericity applied in this research can guide the fabrication of arbitrary RNA nanostructures, with various applications," concludes Prof. Tamura.

• Biochemistry Research
• Cell Biology
• Earth Science
• Origin of Life
• Charles Darwin
• Molecular biology
• Genetic code
• Origin of life

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Materials provided by Tokyo University of Science . Note: Content may be edited for style and length.

Journal Reference :

• Yuna Akatsu, Hiromi Mutsuro-Aoki, Koji Tamura. Development of Allosteric Ribozymes for ATP and l-Histidine Based on the R3C Ligase Ribozyme . Life , 2024; 14 (4): 520 DOI: 10.3390/life14040520

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New study shows how quickly surface water moves to groundwater reservoirs across Australia

A new study from Charles Darwin University (CDU), Monash University and The University of Newcastle has presented almost 100,000 estimates of groundwater recharge rates across Australia, by far the largest known database of its kind.

Groundwater recharge is the rate at which groundwater resources are replenished by rainfall in millimeters per year (mm/y).

The recharge rates estimated for the Darwin area typically ranged between 150 and 420 mm/y, compared to values typically less than 2 mm/y around Alice Springs. In both cases, these values are only a fraction of the total annual rainfall.

The recharge rates estimated for the Beetaloo Sub-basin typically ranged between 1 and 50 mm/y, with an average of 16.5 mm/y.

CDU Ph.D. candidate and lead author Stephen Lee said the study used recently developed approaches to estimate recharge, and several existing datasets, aiming to aid water resource managers to improve their knowledge of how water interacts with and moves through the earth.

"Previous studies of global groundwater recharge have collated around 5,000 estimates, that were generated using a range of different methods, components, and durations of time," Mr. Lee said.

"This makes it a challenge to predict regional or global-scale recharge rates. In comparison, our study has used a single method to make consistent estimates of groundwater recharge in various Australian climates. We have created a map of these points that is now available to the public."

Researchers focused on chloride concentrations, a naturally occurring ion that is present in both fresh and salt water.

They generated a high-resolution model of recharge rates across climate zones in Australia, including arid zones in Western Australia where data has been limited.

"Our recharge rate estimates are notably lower than other studies, but we have provided more diversified coverage of arid areas, which make up most of Australia, whereas past studies were more focused on the tropics and temperate climates," he said.

"Along the east coast, higher rainfall and less evaporation due to temperate and tropical climates lead to higher recharge rates, and more dry, arid regions have less rainfall and lower recharge rates."

"For example, you can compare the Top End's low concentration of chloride in groundwater and high rainfall to high concentrations and low rainfall in Central and South Australia. Recharge rates generally increase the further north the area is."

Knowledge of groundwater recharge is vital for effective water resources management.

Mr. Lee said groundwater is vital for ecosystem survival, drinking water supply, agriculture, and other primary industries in the many areas where groundwater is the only reliable water source.

The findings also highlight that climate variables such as rain, seasonality, and potential evaporation from trees and vegetation significantly influence recharge rates.

"This study represents a significant step forward in groundwater recharge estimation," he said.

"We've used data that is often neglected, and we hope that by making it more accessible and interactive, the study will enable researchers and the water resource management industry worldwide to manage water resources better and mitigate the impacts of climate change."

Supervisor Dr. Dylan Irvine said the results could be used by researchers, government, industry, and the public to understand groundwater in their region.

"Despite its importance in water resources management, we can only estimate groundwater recharge," Dr. Irvine said.

"Here, we've provided the largest groundwater recharge dataset produced anywhere, and we've also produced a modeled map of recharge that can be used as a starting point in investigations where no recharge estimates are available."

The research is published in the journal Hydrology and Earth System Sciences .

More information: Stephen Lee et al, A high-resolution map of diffuse groundwater recharge rates for Australia, Hydrology and Earth System Sciences (2024). DOI: 10.5194/hess-28-1771-2024

Provided by Charles Darwin University