Charles Darwin
Main contents
- Charles Darwin
- Personal Life
- The HMS Beagle
- The Source of Darwin’s ideas
- Darwin’s Influences
- On the Origin of Species by Means of Natural Selection
- Problems with the Theory
- Public Reaction
- Darwin’s contemporaries
Charles Darwin is often depicted as the Father of Evolution, the first man to think of it. But the idea of evolution has a long and complex history. Even in the mid 1800s, many other researchers were working on the same ideas. So why is it Darwin we tend to celebrate?
Charles Darwin was the first to develop evolution into a comprehensive and well-evidenced theory. He took 20 years of his life drawing on the work of 2,000 other researchers, trying to anticipate the questions and objections that would be raised. In doing so, he made himself into a figurehead for the theory, even though he was the first to acknowledge the contribution of others.
The irony of this is that he didn’t like the limelight. He hated being a public figure and spent most of his life at home in Downe, Kent.
It is right we remember Darwin as a great scientist, and it is fair to see him as one of the founders of modern biology. But we have to be careful not to associate the man and the theory too intimately. Evolutionary theory today has changed a great deal from Darwin’s time. Some of Darwin’s ideas were wrong, and in other areas he had limited data to work from. This wasn’t his fault; he didn’t have all the facts we do. The discoveries of the 1900s and 2000s have refined the theory of evolution and demonstrated its essential facts.
Personal Life
Early Life
Charles Robert Darwin was born in Shrewsbury 12 February 1809. His father, Robert, was a doctor. His paternal grandfather was also a doctor, the famed naturalist Erasmus Darwin who had written on the subject of evolution in the late 1700s. His mother, Susannah, was the eldest child of the famous potter, Josiah Wedgwood I.
This placed Charles Darwin within two well-respected families. Both families were liberals, supporters of abolitionist movements and advocates of the rights of man. Darwin himself was not politically active, but many members of his family were.
Charles Darwin was raised as an Anglican, though his father was openly atheist (he did not believe in any god). His mother, Susannah, had been raised as a Unitarian (Unitarian’s are Christians, but they reject the idea that Jesus was God), but preferred to raise her children in the Church of England. This meant that rather than being exposed to radical ideas on religion, Darwin was brought up with the same ideas about God as the majority of the country. Although often depicted as an atheist, Charles Darwin believed in God for most of his life.
Susannah died in 1817 when Charles was just 8. His father was quite a stern figure, most simply referred to him as ‘The Doctor’, and Darwin was primarily raised by his older sisters. He also spent as much time as possible at the house of his uncle, Josiah Wedgwood II. Darwin referred to him as ‘Uncle Jos’ or ‘Uncle Jo’.
Darwin was sent to Shrewsbury School were he boarded, despite the proximity of his family home. it was here that he first took an interest in Natural History, establishing a society for other students interested in nature. At 16, in the summer of 1825, he spent some time assisting his father in his medical practice. Although he wasn’t close to ‘The Doctor’, Darwin greatly admired the efforts his father made to help his patients.
Although Darwin was already interested in natural sciences, this was not a career option open to him. Natural history in the early 1800s was not a professional subject, it was a hobby for wealthy gentlemen, doctors and the clergy. Darwin’s family was wealthy enough that he didn’t need to work, but his father was insistent he should have a career. There were two respectable career options for a young man of his standing; medicine and religion. In late 1825, he started a degree in medicine at Edinburgh University.
Edinburgh 1825 to 1827
In his autobiography, Darwin largely dismissed his time at Edinburgh University. He didn’t enjoy the course, hated the brutality of surgery, and was quite squeamish.
But recent biographers, notably Moore & Desmond, have suggested this time may have been more important than originally thought. When you look at the influences he was exposed to, the debates going on around him, and the interests he developed, it’s hard to disagree with their assessment.
While he hated his medicine lectures, he continued to take an interest in natural history. It was expected that doctors would know some botany, and most courses threw in a little geology and zoology too. Darwin also joined the Plinian Society, a society for student naturalists. So Darwin was now learning the subjects that would later dominate his life. He started to skip medicine lectures, preferring to work with Robert Grant. Grant was a trained doctor, but had essentially given this up to study marine life. Darwin assisted him in these studies.
Even more significantly, Grant was a believer in evolution. He had read Erasmus Darwin’s works and was influenced by Lamarck and Saint-Hilaire. Here we see Charles Darwin first being opened to the idea of evolution, with a passionate teacher he respected arguing it’s merits. Darwin also read the criticism of his grandfathers work, the first time he’d have seen the risks of publishing on radical thinking. Given Darwin’s own later reluctance to publish, it’s hard to imagine this didn’t have some influence.
Another important aspect of Darwin’s time at Edinburgh came from an external influence. John Waterhouse was a former slave, a black man, who had accompanied Charles Waterton on expeditions to South America. He had been taught taxidermy and specimen preservation by Waterton, and he taught these skills to students at the University for a small fee. Darwin had a weekly session with John for the best part of a year. The first important point here is that this was still quite shocking in the early 1800s. The idea of a respectable young white man learning from a black slave would have offended a large part of society. But Darwin writes of his tutor with great affection and respect. It is clear he did not see any difference between the two on racial grounds. John also thrilled the young Darwin with stories of his adventures with Waterton. The idea of travel, a naturalist’s collecting expedition, fired his imagination. The following year travel diaries formed a large portion of his reading.
In late 1827 Darwin’s father removed him from Edinburgh after just 2 years. Charles never got his medical degree. Having failed at medicine there was only one other option open: the clergy. But Robert Darwin was not convinced his son would ever make anything of himself. In 1828 he said:
"You care for nothing but shooting, dogs, and rat-catching, and you will be a disgrace to yourself and all your family"
Darwin reflected in his autobiography that his father was probably right, that was the direction he had been heading.
In early 1828 Charles started a general degree at Cambridge University. His father hoped he would settle down and join the clergy. He was to be disappointed.
Cambridge 1828 to1831
In the early 1800s there was no official route into the clergy. A general degree, one that took in elements of philosophy, divinity, theology, mathematics and natural sciences, was regarded as a suitable qualification. If he was to join the clergy, he would have to accept the Anglican creed. Darwin read a number of books that argued the evidence for God. Satisfied that the arguments were logical, he took up his studies.
Again, the older Darwin dismisses his education as dull and worthless. He could not take to mathematics, something he later regretted. To his father’s dismay, he continued to involve himself in shooting and hunting, and now socialised with similar young men, spending enjoyable evenings drinking and dining. His greatest pleasure at Cambridge was collecting beetles, a popular activity at the time.
It was his learning away from the principle lectures that really shaped his future. We should not be surprised to learn that Darwin continued to take an interest in natural history, attending many public lectures. He developed a close relationship with his Botany tutor, the Reverend John Stevens Henslow. Henslow was well-loved by most of his students. He was incredibly intelligent. although theoretically a botanist, he took an interest in everything; entomology (the study of insects), geology (the study of rocks), mineralogy (the study of minerals), chemistry, zoology (the study of animals) and anatomy (the study of the body).
While Henslow always picked out several favourite students, he had a particularly close relationship to the young Darwin. Darwin regularly ate with Henslow’s family and the two took long walks in the countryside, probably discussing Darwin’s future and possible adventures. Darwin loved him and in his autobiography he cites Henslow as the greatest influence on his career. You see much of Henslow’s approach and methods in Darwin’s own scientific endeavours. The two were constant companions and Henslow remained a mentor and trusted confidante throughout Charles’ life.
Despite these distractions, he applied himself well and in January 1831 graduated 10th in his class of 178, excelling in theology. His understanding of the key texts was noted. His intention remained to join the clergy.
Having graduated, he had time to himself in Cambridge. Darwin was already planning a future as a naturalist and took a course in Geology in his own time. He was taught by the Reverend Adam Sedgwick, Cambridge’s geology tutor. He had avoided these lectures originally and wanted to catch up. However, Darwin at this time still didn’t really take to the subject. He also used his time to read William Paley’s Natural Theology, the foundation of Intelligent Design. This was not an essential text, but Darwin had an interest in the natural world and held Paley’s views in high regard. He would later refute Paley’s ideas in his own work, though he acknowledges his respect for Paley’s logic.
Henslow had one great regret, he had never really travelled, though he had always wanted to see Africa and South America. The two planned a student expedition. But a combination of circumstances meant this never happened. Instead, Darwin joined the crew of HMS Beagle in late 1831 (see Section 2.2).
Marriage and Family 1838 to1882
When he returned from the Beagle’s five-year voyage, Darwin knew what he wanted to do and had found his purpose. But he also thought about his own family life. Should he marry? Would he have children? Where would they live?
Being a rational man who always liked to order his thoughts, he sat down in 1837 or 1838 and wrote out a list of notes giving the reasons for and against marriage as he saw them. A wife brought children, companionship and charm. Darwin found the notion of 'a nice soft wife on a sofa' appealing, something to be 'beloved and played with', Less romantically, a wife was a housekeeper, and 'Better than a dog anyhow'. On the downside, a wife would force him to visit relatives. She would restrict his spending and restrict his potential to travel. He would have to work for money and probably find himself stuck in London all his days. She would restrict the company he kept. He would have less time for reading, less money for books. A family brought 'anxiety and responsibility'.
Ultimately, Darwin was clear on his course: 'Marry - Marry - Marry Q.E.D.'
This wasn’t the end of his thinking. He similarly debated when to marry, where to live and what work to take.
On 11 November 1838, which Darwin called 'the day of days', his cousin Emma Wedgwood agreed to marry him. They married two months later on 29 January 1839. Their first child was born later that year. Sometimes, Darwin’s relationship with his wife is characterised as cold and functional. Nothing could be further from the truth. The letters they exchanged clearly show they had a loving relationship. Emma would read to him and play the piano. The pair would play a daily game of backgammon. The fact they made this time for each other, despite Darwin’s passion for his work, shows their affection.
In 1841 his second child, Annie, was born. In understated fashion he notes 'March 2nd. Annie born. Sorted papers on species theory'. While this may seem like he wasn’t interested, this is more a reflection of the time. He loved Annie very much.
In 1842, with two children and a third on the way, they moved to Down House in Bromley, on the outskirts of London. They lived there for the rest of their lives. Darwin surrounded himself with his family and indulged them. The children were given free roam of the house and gardens. They had ten children, although two died as infants.
In 1849 Annie died aged 10. Darwin was devastated. He had already been nurturing doubts about his religious beliefs; the cruelty he’d seen in nature made him question the existence of a benevolent god. But he had previously seen it as a fair price for the wonders of nature. Annie’s death changed this. No longer could he accept this suffering and death as fair. He never saw himself as an atheist, but did become openly agnostic. He would walk his family to the local church, then go for a walk rather than go inside. However, he continued to involve himself in the business of the local parish and was held in high regard by his neighbours.
Darwin rarely left Down House. It served as his office, his study and his laboratory. He conducted experiments on selection and breeding in his garden. He made detailed sketches of his children’s faces in different states of emotion which he later used in his study of human nature. In addition to On the Origin of Species, he produced excellent scientific work on the formation of coral reefs, overturning the prevailing view and proving how different reefs formed. He also wrote about geology, barnacles, botany, earthworms, domestication, human evolution and human emotion.
Darwin died 19th April 1882 aged 73. He was given a state funeral and buried in Westminster Abbey. He had actually wanted to be buried in the churchyard at Downe, but his supporters pressed for the greater honour of Westminster. Several years after his death there were claims he had made a deathbed conversion, renouncing his theories. This is not supported by the evidence and has been flatly contradicted by his family. The woman who made the claims was known to be a great self-promoter and probably saw it as an opportunity to add to her reputation.
HMS Beagle
HMS Beagle was a surveying ship. It had already made one voyage around South America between 1826 and 1830, but that trip had been disrupted by the suicide of the Captain, Pringle Stokes. The eventual replacement, Robert FitzRoy, was to captain the Beagle’s second voyage of 1831-1836.
FitzRoy was wary of what had happened to Stokes. He wanted to avoid similar depression taking him, so decided to hire a Ship’s Naturalist. In reality, this would be an educated young gentleman who would give him civilised company and conversation. FitzRoy had intended the role for a friend of his, but this fell through. He wrote to several professors at Cambridge, among them Charles Darwin’s mentor John Henslow. Henslow, and others, recommended the young Charles Darwin for the role.
Henslow wrote to Darwin, explaining why he should take the role. The problem was it was an unpaid position, and Darwin would need his father to pay the substantial sum of £500 to secure the place. Initially, Robert Darwin was reluctant to back his son. He thought the role was unsuited to a prospective clergyman and saw it as a way for his layabout son to put off a proper career. He also worried his son would not take to a life at sea, a concern that would prove to be justified. The limited preparation time was a major concern that Charles shared.
In the end, Robert said he would agree to fund the trip if Charles could find a respectable man to back the trip. There was no-one Robert Darwin respected more than his brother-in-law, Josiah Wedgwood II. So Charles turned to his Uncle Jos. Wedgwood agreed with Henslow that this could be the making of young Charles and added his support. Thus convinced, Robert Darwin put the money up and Darwin took his place among the crew of HMS Beagle. On 27 December 1831, the ship left Plymouth en route to Brazil. The trip was intended to last two years, but it would be five years before they saw England again.
Almost immediately, his father’s warnings came back to haunt him. Charles Darwin fell seasick, and remained so for almost the entire journey. He took every opportunity to get on to land, spending more than three years on shore. Any time the ship could proceed without him, Darwin would pack up and explore the land. This hatred for travel was part of the reason he remained in England the rest of his life.
Another of his father’s concerns was that Darwin may not get on with the Captain. FitzRoy was a supporter of slavery and a religious conservative. In many ways he was the exact opposite of Charles Darwin, so it was a valid concern. However, while they did fall out dramatically on more than one occasion (most notably when FitzRoy banned Darwin from dining with him for condemning slavery), they generally got on well. FitzRoy later said he couldn’t have asked for a more suitable companion.
Darwin’s principle role, apart from keeping the captain sane, was to collect specimens for shipping back to England. Drawing on the teaching of John Stevens Henslow and John Edmonstone (section 2.1), he was extraordinarily successful. He sent five crates, containing thousands of specimens, back to Cambridge. Henslow arranged for the specimens to go to the best researchers for study. Darwin wondered about the value of the specimens he sent back, but in March 1834 he got a letter from Henslow praising Darwin’s collection. Darwin didn’t know it yet, but he would return to England a minor celebrity on the back of his discoveries.
But Darwin also made observations everywhere he went, looking at the geology, the flora and the fauna around him. He was amazed at the sheer variety of life on Earth, particularly in the rainforests where he seemed to find new specimens for collection at every turn. He found remarkable fossils of giant extinct mammals. He had previously failed to take to geology, but Henslow had given him a copy of Sir Charles Lyell’s Principles of Geology Vol. 1 to read on the journey (he sent Vol. 2 out later to meet Darwin in Argentina). Now, seeing the remarkable volcanic islands and the aftermath of earthquakes, he was consumed with passion for the subject. He decided geology was even more enjoyable than the first day of a partridge shoot. These observations made Darwin question the accepted wisdom on the natural world. He was convinced by Lyell’s arguments for the age of the Earth and began thinking about evolution in this light.
He saw slave plantations first-hand, confirming the horrors he had heard of back home as a young man. He met many 'savage' races in South America, Australia, New Zealand and Polynesia. He was shocked at their appearance and lifestyle and could understand why many considered they were lesser races. But at the same time he expressed the belief that the inner differences were much smaller and that the 'savage' lifestyle was more about habit than any deeper reflection of their nature. In particular, he was impressed by the intelligence and bearing of those that had been educated as missionaries. They proved that anyone could elevate their standing.
In September 1834 Darwin fell seriously ill while trekking in Chile. He was bed-ridden for around a month. He suffered with serious illness his entire life, particularly at times of anxiety. This has led many to assume the illness was mental, but it is also possible he contracted a blood disease that was inflamed by stress. We will never know for certain.
While Darwin was ill, FitzRoy had a falling out with the Admiralty and resigned as captain. Robert FitzRoy was of noble blood. He considered that from the moment the ship left port, all decisions were his and beyond question. But he had received a letter questioning his spending. This caused him to have a minor breakdown. Fortunately, he eventually calmed down and was persuaded to withdraw his resignation. He didn’t change his approach to captaincy, and in late 1835, with Darwin fully recovered, he sanctioned an unscheduled trip to the Galapagos Islands. Given the importance many place on this location, we can also see the significance of FitzRoy resuming his captaincy. Either of his lieutenants would have simply finished the survey of South America and returned to England.
The Beagle was in the Galapagos for around a month. The animals Darwin saw there, the finches, mockingbirds and giant tortoises, are today seen as key in formulating his theory. But in reality, he didn’t appreciate the significance of these specimens till many years later. If anything, it was the fascinating geology that really fired his imagination.
The Beagle eventually returned to Plymouth on October 2nd 1836. Darwin would refer to the voyage as 'the most important event of my life'. His theory of evolution was not the product of any one thing, it was the combination of all the influences on his life going back to childhood. But it’s fair to say the time on the Beagle opened his eyes to the natural world and started a conscious thought process that would lead to his most famous work.
Source of ideas
Accounts of Darwin’s work tend to emphasise single events, such as visiting the Galapagos, as key to writing Origin. But the truth is Darwin’s ideas came from a range of influences throughout his life. Although the idea of evolution was already in his mind, Darwin didn’t rush his theory into print; he spent 20 years backing his ideas with a wealth of evidence.
While travelling he found animals that were broadly similar but with subtle variations. Different habitats and islands had varieties of the same basic form. He often found that on one group of islands you would find several animals, for instance Mockingbirds, that were broadly similar but with subtle variations in plumage and beaks. Each island had it’s own slightly different variety. To Darwin, this suggested a common ancestor.
He also thought about populations. If every animal bred successfully, with it’s descendants all breeding successfully, and so on, the Earth would be over-run within a couple of generations. In fact, most animals die before they have a chance to reproduce; natural factors control the population. Animals that survive to breed must have made it through a process of selection and therefore must be slightly better suited to their environment than other individuals.
Darwin kept pigeons and dogs and experimented with plants in his own garden. He was amazed at the sheer range of forms that could be achieved in a short space of time by breeding for selected features. Breeds of pigeons were often so different that a biologist could mistake forms for different species.
Darwin was also keen on geology, and particularly Charles Lyell’s ideas on the age of the Earth. Darwin agreed with Lyell that the Earth had to be of great age, hundreds of millions of years.
Since remarkable variety could be achieved in a short time through selective breeding, surely given much longer to work, all the variety of life could be similarly accounted for by a process of natural selection?
Influences
Darwin did not work in isolation. His theory of evolution drew on and built on an extensive heritage (only some of which Darwin would have read).
The work of Hutton, Lyell and Lord Kelvin had shown that the Earth was much older than previously believed. Establishing this timeframe was essential to allow Darwin’s ideas to work. The ideas on evolution and extinction discussed by Cuvier, Buckland, LeClerc, Lamarck, de Candolle and Maupertuis all helped provide the intellectual framework for Darwin. Carolus Linnaeus’ work on classification was also a source of inspiration.
His brother gave him a copy of Thomas Malthus’s work on populations, and we know this was a definite influence on the idea of natural selection. Malthus established that limited resources act as a check on human population growth. Darwin believed this same principle could be applied to the natural world.
Darwin’s mentors at university, particularly John Henslow, set the course of his life. Darwin collected a vast quantity of new specimens while on the Beagle and relied upon a number of other scientists to describe, classify and interpret them, including:
William Buckland (geology), Christian Ehrenberg (microscopic organisms), John Gould, George Gray (birds), John Henslow, Joseph Hooker, William Hooker (plants), Leonard Jenyns (fish), Richard Owen (fossil vertebrates), George Sowerby, John Morris, Daniel Sharpe (fossil shells), James Stephens, Francis Walker, Frederick Hope (insects), Gabriel Bibron, John Gray, Thomas Bell (reptiles & amphibians), George Waterhouse (insects), William Martin, J Reid (Mammals), Adam White (Arachnids)
Over 20 years, Darwin wrote to around 2,000 people as he patiently compiled evidence for his 'Species Book'. Charles Lyell became a regular correspondent, as did Thomas Huxley. Joseph Hooker was another close friend Darwin relied on.
Among the many people Darwin drew on, not all initially supported him on evolution. Some never did.
On the Origin of Species
In July 1837 Charles Darwin started his first 'Transmutation Notebook'. These were the books in which he jotted down his ideas about evolution. Over the next two years he explored his ideas, often writing quickly in a stream of consciousness. Half-remembered titles from books and papers were noted, conversations were recalled and jotted down. By reading these books we can see the process that lead him to his theory of evolution by natural selection. Ideas appear and are dismissed. Others develop through the books. They give an insight into the remarkable way Darwin’s mind worked.
In 1842 while visiting relatives he scribbled out the first outline of the theory. On 5 July 1844, seven years after first starting to consider it, he wrote a 230 page 'Sketch of Species theory'. Yet it would still be another 17 years before the final manuscript was published. The popular perception is that Darwin was afraid to publish. There may be some truth in this, but it is certainly not the whole story. Darwin’s obsessive nature meant he always found more to learn, more experiments to conduct, more evidence to draw in. He couldn’t call the theory finished.
In 1857 Darwin had a letter from Alfred Russel Wallace, a young biologist who had reached the same conclusions as Darwin. This finally forced Darwin to prepare a version of his theory for publication. In 1858, when Origin was only half-written, Wallace made it clear he was about to publish on Natural Selection. It was agreed their work would be presented jointly at a meeting of the Linnean Society. With Wallace out of the country and Darwin sick, their mutual friends Charles Lyell and Joseph Hooker presented Darwin and Wallace’s papers on July 1st 1858. The initial impact was negligible.
On 22nd November 1859 the first print run of On the Origin of Species went out to booksellers. There were 1,250 and, thanks to advance orders, it was immediately sold out. The title of Darwin’s most famous work is often shortened, incorrectly, to On the Origin of the Species. This implies the book deal with just the one species; ours. In fact, Darwin hardly ever mentions humanity in his book. The full title is On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life. The use of the word ‘races’ suggests Darwin is talking about humanity, but this is not the case. It was common practice to use the word ‘race’ to refer to any variety within a species. It is in that context Darwin is using it.
'...the origin of species – that mystery of mysteries'
-Introduction, On the Origin of Species, Charles Darwin
Darwin’s book is about how new species emerge, not where life came from. During his voyage on the Beagle, and over the 20 years prior to the publication of Origin, Darwin came to realise that biology lacked a true unifying structure.
'...that the characters which naturalists consider as showing true affinity between any two or more species, are those which have been inherited from a common parent, and, in so far, all true classification is genealogical; that community of descent is the hidden bond which naturalists have been unconsciously seeking...'
-Chapter XIII, On the Origin of Species, Charles Darwin
Linnaeus’ Systemae Naturae had set out a classification that defined similarities, but nobody had made the push to the logical conclusion of this idea; since we could classify organisms based on levels of similarity, surely they were just branches of one extended family tree?
'As buds give rise by growth to fresh buds, and these, if vigorous, branch out and overtop on all sides many a feebler branch, so by generation I believe it has been with the great Tree of Life, which fills with its dead and broken branches the crust of the earth and covers the surface with its ever branching and beautiful ramifications.'
-Chapter IV, On the Origin of Species, Charles Darwin
Darwin was very interested in the many and varied breeds of domestic animals. He rightly noted that the range of variation, if given to a biologist, would see breeds of a single species classified as different species on the basis of their extreme physical dissimilarity.
'...varieties are species in the process of formation, or are, as I have called them, incipient species.'
-Chapter IV, On the Origin of Species, Charles Darwin
From this, he made a logical, yet difficult, leap. Since such variety could be achieved in a short time through breeding, surely given much longer to work, all the variety of life could be similarly accounted for?
'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.'
-Chapter IV, On the Origin of Species, Charles Darwin
The key to Darwin’s realisation was geology. Charles Lyell’s work on the age of the Earth, proving that it was far older than originally suspected, gave the immense time Darwin’s theory required.
'He who can read Sir Charles Lyell’s grand work on the Principle of Geology, which the future historian will recognise as having produced a revolution in natural science, yet does not admit how incomprehensibly vast have been the past periods of time, may at once close this volume.'
-Chapter IX, On the Origin of Species, Charles Darwin
Biologists already knew there was variation in any given species. By combining this variation, his knowledge on domestication, and the vast span of geological time, Darwin reached his conclusion.
'In such case, every slight modification, which in the course of ages chanced to arise, and which in any way favoured the individuals of any of the species, by better adapting them to their altered conditions, would tend to be preserved; and natural selection would thus have free scope for the work of improvement.'
-Chapter IV, On the Origin of Species, Charles Darwin
Intriguingly, the word 'evolution' is never used. The word 'evolved' appears in the last line.
Problems with his Theory
Darwin knew his ideas would be debated and correctly identified several problems with the theory.
'That many and grave objections may be advanced against the theory of descent with modification through natural selection, I do not deny.'
-Chapter XIV, On the Origin of Species
However, he tried to address these issues and provide answers.
'Grave as these several difficulties are, in my judgment they do not overthrow the theory of descent with modification.'
-Chapter XIV, On the Origin of Species
Transitional Forms
An objection still levelled at Darwin’s theory is that we have no 'transitional forms', no fossils marking the transition between major groups.
'...if my theory be true, numberless intermediate varieties, linking most closely all the species of the same group together, must assuredly have existed; but the very process of natural selection constantly tends, as has been so often remarked, to exterminate the parent-forms and the intermediate links. Consequently evidence of their former existence could be found only amongst fossil remains, which are preserved, as we shall in a future chapter attempt to show, in an extremely imperfect and intermittent record.'
-Chapter VI, On the Origin of Species
In Darwin’s day, this was a valid criticism (since then thousands of fossils have been discovered, representing most major transitions). Darwin had two answers for this.
'For my part, following out Lyell's metaphor, I look at the geological record as a history of the world imperfectly kept, and written in a changing dialect; of this history we possess the last volume alone, relating only to two or three countries. Of this volume, only here and there a short chapter has been preserved; and of each page, only here and there a few lines. Each word of the slowly changing language, more or less different in the successive chapters, may represent the forms of life, which are entombed in our consecutive formations, and which falsely appear to have been abruptly introduced. On this view, the difficulties above discussed are greatly diminished, or even disappear.'
-Chapter IX, On the Origin of Species, Charles Darwin
One was that the fossil record was very poor. Little was preserved, so finding proper chains was an impossibility. There is more than a little truth in this. Fossilisation is exceptionally rare; less than 0.001% of life on Earth is likely to form a fossil. This means Darwin’s transitions are rare. But we also know that evolution is not always the slow gradual progression Darwin imagined. Evolution can, in fact, move much more rapidly. Allied to the rarity of fossilisation, this makes it even more remarkable that we have any of these fossils.
'I have found it difficult, when looking at any two species, to avoid picturing to myself, forms directly intermediate between them. But this is a wholly false view; we should always look for forms intermediate between each species and a common but unknown progenitor; and the progenitor will generally have differed in some way from all its modified descendants.'
-Chapter IX, On the Origin of Species
Darwin’s second answer was to caution against imagined missing links. In this, he was quite right. If we imagine two related animals, B and C and a hypothetical transitional form, A:
It’s easy to picture A, a transitional form, as being an amalgam of B and C. But this would be incorrect.
For starters, this assumes that an even amount of change has happened on each branch of the tree. It could be that C is little different from A, and B is quite different. In which case, the 'transitional form' would look like C, little like B.
If we imagine the degree of change is about even, the key features of B and C are derived, not the same, as the ancestral features. So A would look like a combination of more primitive versions of B and C. This is much more difficult to identify.
Finding D then becomes important, because it will give us an idea what more primitive features look like. It will also give us an indication if either B or C is nearer to the ancestral form.
We can see from this that Darwin was right. 'Missing Links' are an unscientific concept. Instead, we have to deal in chains of fossils, accepting that gaps in the chain are unavoidable. We can think of it like a giant game of hangman, with very long, complicated words. Each time you get a new letter, you are closer to seeing the whole word.
Irreducible Complexity
‘Irreducible Complexity’ is the idea that organisms, or parts of organisms, are too complicated to have arisen through evolution. Because they rely on several parts, all the parts would have to appear at the same time, or the whole thing wouldn’t work.
'To suppose that the eye, with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest possible degree.'
-Chapter VI, On the Origin of Species
This is probably the most misquoted sentence in Darwin’s book. His detractors use it to suggest Darwin doubted his own ideas. However, this is not the case. The critics are not reading Darwin properly, and they have not bothered to study Darwin’s influences. If we turn back to William Paley, we find he uses a very similar phrase when discussing God as a designer. Darwin is merely using Paley to set out a possible objection. Immediately following this sentence, in the same paragraph, we read:
Yet reason tells me, that if numerous gradations from a perfect and complex eye to one very imperfect and simple, each grade being useful to its possessor, can be shown to exist; if further, the eye does vary ever so slightly, and the variations be inherited, which is certainly the case; and if any variation or modification in the organ be ever useful to an animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, can hardly be considered real.'
-Chapter VI, On the Origin of Species, Charles Darwin
The next three pages of Origin address this question and discuss how exactly this complex eye could come about.
Darwin suggests that if we study the natural world, and we can find all the steps necessary to construct a human eye gradually, then we disprove the idea of irreducible complexity. He was right. If we study nature, we find around 60 different types of eye (every organism has it’s own unique eye, but we can classify them into basic types to make it easier to study). Different eyes have different levels of complexity, and we find some types lack parts our eye has (and some that have parts our eye doesn’t). They function differently, but still work. We can identify examples that represent the necessary stages to build an eye like ours gradually, proving such a structure could evolve. This is supported by genetic study.
Public Reaction in 1859
Darwin’s theory was not as controversial as we tend to think. The 19th Century scientific world had been transformed by a succession of breakthroughs. It was the scope of Darwin’s work that produced outrage.
In the early 1600s most people believed the Earth to be 6,000 years old and that all life had been created by God. But from the late 1600s new ideas on the age of the Earth, extinction and the nature of life transformed the world. By 1859 most people believed the Earth had seen a series of 'revolutions', mass extinctions in which one set of specially created forms replaced another.
What made Darwin’s idea controversial was that it reduced the creation to just one, or very few, early forms. Everything else had arisen by Natural Selection. Even Darwin’s most loyal supporters took issue with the magnitude of change Darwin attributed to Natural Selection. Despite the wealth of evidence Darwin accumulated, most people couldn’t make the leap from selection producing small changes, to selection accounting for all the variety of life on Earth (even though this is just a matter of timescales).
The most contentious issue though was human evolution. Darwin did not discuss human evolution in Origin of Species but the implication was that humans were the same as other animals. The idea of humans as anything other than 'specially created' was fiercely rejected.
Darwin’s work would have been much more controversial had it not been for an 1844 book called Vestiges of the Natural History of Creation. It was a philosophical work on evolution, but like Darwin’s later work it reduced God’s creation to one act and placed man in among the animals. It actually outsold Origin and probably softened the ground for Darwin’s more scientific text.
Having said that, Darwin was a famous scientist, seen by the general public as an authority on natural history. Vestiges was an anonymous text. So Origin still drew a lot of attention, simply because it was Darwin saying it.
Darwin’s Contemporaries
It’s interesting to look at some of the other scientists who either supported Darwin, or reached the same ideas independently. We can see they all read many of the same books; Charles Lyell’s Principles of Geology seems to have been a key text for most of these early naturalists. They all travelled extensively as young men, collecting new species in places like Australia and South America. We will look at three of them.
Thomas Henry Huxley (1825-1895)
Thomas Huxley was one of Darwin’s most loyal supporters, and defended evolution fiercely in many debates. He referred to himself as Darwin’s Bulldog, a name that has stuck. Huxley’s most famous defence of evolution came in 1860, when he debated Samuel Wilberforce, Bishop of Oxford. Wilberforce was a renowned debater, but most contemporary accounts record Huxley as the overwhelming victor.
Huxley was born in Ealing, London. While Darwin came from a very wealthy and prestigious background, Huxley’s beginnings were more humble. He largely taught himself before eventually winning a medical scholarship. Like Darwin he took a place on a surveying ship. His research work around Australia and New Guinea won him many admirers, including Darwin, Lyell and Hooker. Although he didn’t have their background, he had earned their respect and they saw him as an equal.
Huxley started out as an opponent of evolution but by 1859 he was convinced by the evidence Darwin had collected. When he read Origin he is reported to have said 'How stupid of me not to have thought of that'. Even then he disagreed on aspects of evolution. Huxley doubted natural selection was powerful enough to account for the variety of life on Earth. He thought there were periods of rapid change caused by mutations.
In 1863, four years after Darwin published On the Origin of Species, Huxley published Evidence on Man's Place in Nature. In this book, he set out the evidence for humanity’s status as an ape. Darwin had been reluctant to comment on humanity, but Huxley knew no such fear.
For many years he lobbied to secure a greater resources for science teaching and for science as a standard subject in the school curriculum. In 1861 the first Natural Science degree was developed at Cambridge. Prior to this the only way to learn about natural history was through studying medicine. It was the publishing of Education Act of 1870 that was the real breakthrough. After this, by Government request, Huxley set about devising a course in botany and zoology suitable to train science teachers. It was a course which emphasised the practical aspects of science both in the field and in the laboratory.
In 1892 Huxley served as part of Her Majesty’s Most Honourable Privy Council, advising Queen Victoria on various matters. As a Privy Counsellor, he was on a par with the Archbishops of York and Canterbury. This honour shows how far natural sciences had come in 50 years and how highly regarded Huxley was.
Alfred Russel Wallace (1823-1913)
Wallace was born in Usk in Wales in 1823. Although born in Wales he was English. He was educated in the Grammar School, Hertford and at 13 years old he was already teaching his fellow pupils. Although he came from a good family, they had fallen on hard times and Wallace hard to work from an early age. At 14 he was working for his older brother’s surveying business in London.
In 1843 he took a teaching position at the Collegiate School, Leicester. Here in 1844 he met Henry Bates. Bates fired Wallace’s interest in natural history and they planned a collecting trip to South America. They arrived there in 1848, but by 1850 the two had separated and were working individually. Wallace left after four years. The ship taking his specimens back to England burned and sank and he lost most of what he had collected.
In 1854 he set off for the Malay Peninsula and spent 8 years collecting almost 110,000 insects. It was during this time that he came to the same conclusions as Darwin. Like Darwin he was also inspired by Lyell’s Principles of Geology. In 1857 Wallace wrote On the Law which has Regulated the Introduction of New Species and On the Tendency of Varieties to Depart Indefinitely from the Original Type, which he sent to Darwin, among others. In 1858 Darwin and Wallace’s separate works were presented at a meeting of the Linnaean Society, London.
Wallace was a very energetic person, who had great insight and made many discoveries. When he died in 1913 the New York Times called him "the last of the giants belonging to that wonderful group of intellectuals that included, among others, Darwin, Huxley, Spencer, Lyell, and Owen, whose daring investigations revolutionized and evolutionized the thought of the century."
Henry Walter Bates (1825-1892)
Bates was two years younger than Wallace. He was born in Leicester in 1825. Like Wallace and Huxley, Bates was 'self-made'. He left school early and taught himself natural history. At the age of thirteen, Bates was already working very long hours as an apprentice, translating Homer before breakfast, going to night classes, and making a beetle collection!
He met Wallace in 1844 and in 1848 they set off for South America. Bates spent 11 years in the Amazon, where he discovered thousands of new species of insect. He returned home in 1859 and wrote The Naturalist on the River Amazons (1863). He never travelled abroad again and spent most of the rest of his life as Assistant Secretary to the Royal Geographical Society. He wrote more than 100 articles on entomology, mainly on beetles, and large parts of his collection are in the Natural History Museum, London.
The most important discovery made by Bates was that some animals imitate others to avoid being eaten. He noted this especially in species of butterfly. Some non-poisonous speces had the same colouring as poisonous ones. This is now known as Batesian mimicry. Bates saw this as an example of natural selection in action.
