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Darwin's transmutation

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Darwin's "Thinking Path" at Down House, where he pondered the "transmutation" of species. Image: Ted Grant, Wiki

Darwin's curiosity, energy, intelligence and sheer doggedness were phenomenal. His theory of natural selection continues to be both influential and controversial. Some people find it an incomplete account of the facts. Scholars contend it was "pre-loaded" by ideology. (See below.) Current thinking about Darwin ranges from enormous admiration to doubt.

Beginnings

Born two hundred years ago on this day, Charles Darwin was a lacklustre scholar, but even as a boy he was a collector - "of franks, seals, coins, birds' eggs, and minerals" and he became a crack shot. His father hoped to make his son a doctor, but Darwin detested his medical studies in Edinburgh. Winter lectures left him with "the enduring memory of spending a whole, cold, breakfastless hour on the properties of rhubarb", and he fled surgery because he could not bear to see a patient in pain. (This was before the discovery of anaesthesia.)

Darwin enjoyed coastal walks, was fascinated by the discoveries he made looking through a microscope and left Edinburgh without a degree. He went to Cambridge to earn one and enter holy orders, but true to form he neglected his religious studies to collect beetles in the local fens. He was thrilled when his name appeared in print in a book on entomology and attended the Friday soirées held by brilliant young dons, among them the young botany professor, the Revd John Stevens Henslow.

Darwin's religious studies went better than might be expected, considering that when he was not hunting beetles he was drinking, riding and gambling. He had enjoyed the Revd William Paley's Evidences of Christianity, and did well on the exam. But what he really relished was Henslow's lectures on plants as living organisms and botanical field trips. In his final examination he ranked tenth in the pass list of 178, but he had already decided he would not enter the church.

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Darwin was the recipient of immense generosity from
scientific mentors, fellow scientists and scientific societies.
Watercolour portrait by George Richmond, late 1830s

The Beagle

In 1831, Henslow wrote to him, inviting him to take a two-year voyage to pursue his scientific interests. At first opposed, Darwin's father covered all the considerable equipment and travel expenses for his son. Charles learned preserving techniques. On 27 December 1831 he set off on HMS Beagle, "a converted 10-gun brig, only 90 feet long, capacity 242 tons, popularly known as one of the 'coffin' class". His duties included keeping the captain, who was semi-suicidal, on an even keel.

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Giant Galapagos tortoise

For the next five years, Darwin was seasick whenever he was on board the Beagle. He survived a series of adventures while travelling to some of the most desolate and interesting places in the world.

His itinerary

The Beagle visited the Cape Verde Islands (January 1832), Brazil (April–July 1832), Montevideo and Buenos Aires (July–November 1832), Tierra del Fuego and Cape Horn (December 1832–January 1833, February 1834), the Falkland Islands (March–April 1833, March–April 1834), Patagonia (April 1833–January 1834), the west coast of South America (Chiloé, Valparaiso, Lima: June 1834–July 1835), the Galápagos Islands (September–October 1835), Tahiti (November 1835), New Zealand (December 1835), Australia (Sydney, January 1836; Tasmania, February; King George's Sound, March), the Cocos (Keeling) Islands (April 1836), Mauritius (April–May 1836), Cape Town (May–June 1836), and St Helena and Ascension (July 1836).

Darwin rode hundreds of miles on his inland travels and met gauchos, Patagonians, Tahitians, Maori and Australian Aborigines. He was well-liked for his sense of humour, his coolness in a crisis, and his skill with a gun - he provided the sailors on the Beagle with fresh meat. When the voyage ended he had made thousands of methodical observations of fauna, flora, erupting volcanoes and rising shorelines, had sent crates full of specimens back to Britain and had brought his captain home in one piece.

A terrifying theory

In Britain Darwin farmed out his collections, which included fossils, to scientific specialists. He had become convinced from his observations that geology was dynamic, and he endorsed Charles Lyell's belief that the earth had been slowly shaped over the aeons - "time enough - as he later grasped - for evolution by natural selection to occur". His colleagues confirmed that diversification of species was evident in the finches, mockingbirds and giant tortoises of Galapagos. His fossils suggested that species changed over time. Darwin began to develop a theory to explain what he had found.

He spent the next years studying and assembling scientific evidence for what he called "transmutation" - the mutability of species in response to competition and environmental change and the "descent" of species from a common ancestor. He married a constantly affectionate and supportive wife, became the father of a large brood and secretly developed his theory. To this end he studied barnacles until there was nothing he loathed more. His younger children, who had never known him do anything else "must have supposed that all fathers were similarly employed, for one reportedly enquired about a neighbour, ‘Then where does he do his barnacles?'"

Darwin was becoming well known in scientific circles, but he was worried that his theory of transmutation by natural selection would shock scientists and the public and that he would be socially and professionally ostracized. In 1844 he described natural selection in a 231-page essay then locked it away. He continued to search for evidence, researching seeds, birds and the flight paths of bees. He continued to write. By 1854 he had set down 250,000 words describing his ideas. He believed his theory was important, and he wanted full credit for it, but not just yet. Meanwhile, Alfred Russel Wallace was developing the same theory on the other side of the globe.

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A competitor

Born in 1823, forced to leave school at 12 due to his father's financial ruin, Alfred Russel Wallace learned map-making, geometry and trigonometry from his brother, who was a surveyor. He attended lectures at local scientific societies, and discovered there was no place he would rather be than outdoors, but not as a surveyor.

At twenty-five Wallace left England to launch a natural history collecting expedition in South America. He ascended the unexplored Rio Negro system alone, and was the first to map the area. He was fascinated by the idea of evolution, which had been talked about for decades, but could not figure out how it was supposed to occur. It was an exciting life, shortly to be made more so by catastrophe.

After several years in the wilderness, Wallace packed his huge collection of plants and animals on board a ship to England. He was crossing the Atlantic when the vessel caught fire and sank. His entire collection of plants and animals was lost in the inferno. For ten days Wallace and his shipmates struggled to survive in two leaking lifeboats.

Safely back in England, an undaunted Wallace decided to carry on his collecting operations in the Malay Archipelago. He managed to obtain the support of the Royal Geographical Society, which paid for his travels. Wallace spent the next eight years capturing orangutans, avoiding capture by head-hunters, and collecting 125,660 specimens, including more than a thousand species new to science. Looking at his collections he was sure that species changed over time and place, but how?

In February of 1858, while sweating through an attack of malaria in his hammock, Wallace recalled Malthus' Essay on Population, and suddenly realized the importance of survival of the fittest - individual organisms that are best adapted to their local surroundings have a better chance of surviving, and passing along their traits to their descendants. As soon as he was well, he dashed off an essay on natural selection and sent it by ship to Charles Darwin.

A lit charge of dynamite

When Alfred Russel Wallace's letter from the Malay Archipelago arrived, it had the effect of a lit charge of dynamite. Not wanting to lose credit for his virtually identical theory, Darwin and Lyell, a mutual friend of Wallace's, submitted Wallace’s essay and Darwin's on the subject of natural selection to the next meeting of the Linnean Society. Their double paper was published a little later. There was not enough time to notify Wallace until afterwards, and he might have felt his idea should take precedence, but he responded generously. Darwin moved swiftly.

On the Origin of Species

In the ensuing year, despite chronic illness and family tragedy, Darwin wrote a compact and readable description of his theory of natural selection, and published On the Origin of Species. He drew on comparative anatomy, embryology, paleontology, and ethology (the study of behaviours) to provide evidence for the theory, and tried to answer in advance the questions of critics. The book was a sensation. His critics "drew the one conclusion that Darwin had avoided mentioning - that mankind was descended from apes." The theory became forever identified with his name.

Questions

Christopher Booker points out that

Darwin did not, of course, originate the idea that life on earth had evolved. This notion went back to the ancient Greeks, and was accepted by many of Darwin's predecessors, including his own grandfather Erasmus. The novelty of Darwin's thesis was his claim that evolution could be explained solely by the process of natural selection, whereby an infinite series of minute variations gradually turned one form of life into another

One great stumbling block to his argument is that evolution has repeatedly taken place in leaps forward so sudden and so complex that they could not possibly have been accounted for by the gradual process he suggested - "the Cambrian explosion" of new life forms, the complexities of the eye, the post-Cretaceous explosion of mammals. Again and again some new development emerged which required a whole mass of interdependent changes to take place simultaneously, such as the transformation of reptiles into feathered, hollow-boned and warm-blooded birds.

As even Darwin himself acknowledged, these jumps in the story might have seemed to render his thesis 'absurd'. He might therefore have recognised that some other critically important but unknown factor seemed to be at work, an 'organising power’ which had allowed these otherwise inexplicable leaps to take place.

Darwin stuck by his guns: I am convinced that Natural Selection has been the main [or ‘most important’] but not exclusive means of modification.

His work received torrential criticism from those who believed his theory cast doubt on the account of creation in Genesis and on a Creator. Some allies responded by saying that nothing in Darwin's theory is necessarily at odds with a Creator - who chose natural selection as a tool that would help species to respond to and adapt to change.

Revelations

Despite feeling unwell much of the time, Darwin plugged on. He was interested in how men had used selection to breed animals and he published a stream of papers on flowers and insects. In 1868 he began The Descent of Man, which included a long description of sexual selection in the animal kingdom and a family tree for humans which connected humans with apes. He had finally revealed exactly what he believed to the world.

Darwin helped scientific colleagues who needed financial assistance and founded a friendly society - a local community group - one of many in Britain - which provided a financial safety net in the case of death or unemployment for members and their families. Late in his life he exhaustively studied and wrote about earthworms, concluding that without the work of worms in transforming soil, agriculture would be impossible. His last evolutionary work was The Expressions of the Emotions in Man and Animals.

Darwin called his state of mind "agnostic". He is said to have "disapproved of socialists, ultra-radicals, and neo-Malthusians (that is, birth-controllers) no less than atheists, spiritualists, and bishops". But he seems to have had spiritual feelings about his theory because he wrote that natural selection tended "to progress toward perfection" (Origins / Recapitulation and Conclusion). This is a silly remark from a scientist and would never be made by a saint.

When he died in 1882, "Darwin's personal reputation did not guarantee the success of his ideas. The Origin of Species, never out of print, was translated into at least thirty-six languages, but its theories were often too materialistic for idealists and too capitalistic for socialists, too empiricist for Germans and too English for the French."

Nevertheless he became the biggest name in modern biology. Darwin's children and grandchildren formed a phalanx of publicisers and keepers of the flame.

As hundreds of thousands of pages of his notes became accessible, it became clear to scholars that

"Central to Darwin's theorizing was his effort to explain the descent of human beings - body, mind, and society - from ape-like animals on the basis of a materialist or monist metaphysics and using Malthus's principle of population. . .Here at last was compelling evidence that 'man' lay at the core of his work from the start. Darwin did not first formulate natural selection and then apply it to human beings; he drew the theory directly from contemporary (and ideologically loaded) assessments of human behaviour and afterwards concealed its implications for over three decades, until the Descent of Man".

Beginning with loaded assessments does not necessarily make the theory untrue. Still, most people would agree that science is hurt by pre-loading.

That the attachment of biologists to Darwin's theories has assumed "a quasi-theological character" is both a tribute to his achievements and a devastating critique.

The complete works of Darwin are now online.

All quotations are from the Oxford DNB.

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