Charles Darwins

Charles Robert Darwin- (12 February 1809 – 19 April 1882) was an English naturalist, geologist and biologist, best known for his contributions to evolutionary biology. His proposition that all species of life have descended from a common ancestor is now widely accepted and considered a fundamental concept in science. In a joint publication with Alfred Russel Wallace, he introduced his scientific theory that this branching pattern of evolution resulted from a process that he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding. Darwin has been described as one of the most influential figures in human history, and he was honoured by burial in Westminster Abbey.

Darwin published his theory of evolution with compelling evidence in his 1859 book *On the Origin of Species*. By the 1870s, the scientific community and a majority of the educated public had accepted evolution as a fact. However, many favoured competing explanations that gave only a minor role to natural selection, and it was not until the emergence of the modern evolutionary synthesis from the 1930s to the 1950s that a broad consensus developed in which natural selection was the basic mechanism of evolution. Darwin's scientific discovery is the unifying theory of the life sciences, explaining the diversity of life.

Darwin's early interest in nature led him to neglect his medical education at the University of Edinburgh; instead, he helped to investigate marine invertebrates. Studies at the University of Cambridge (Christ's College) encouraged his passion for natural science. His five-year voyage on HMS *Beagle* established him as an eminent geologist whose observations and theories supported Charles Lyell's conception of gradual geological change, and publication of his journal of the voyage made him famous as a popular author.

Puzzled by the geographical distribution of wildlife and fossils he collected on the voyage, Darwin began detailed investigations and in 1838 conceived his theory of natural selection. Although he discussed his ideas with several naturalists, he needed time for extensive research, and his geological work had priority. He was writing up his theory in 1858 when Alfred Russel Wallace sent him an essay that described the same idea, prompting immediate joint publication of both their theories. Darwin's work established evolutionary descent with modification as the dominant scientific explanation of diversification in nature. In 1871 he examined human evolution and sexual selection in *The Descent of Man, and Selection in Relation to Sex*, followed by *The Expression of the Emotions in Man and Animals* (1872). His research on plants was published in a series of books, and in his final book, *The Formation of Vegetable Mould, through the Actions of Worms* (1881), he examined earthworms and their effect on soil.

## Biography

### Early life and education

See also: Charles Darwin's education and Darwin–Wedgwood family

Charles Robert Darwin was born in Shrewsbury, Shropshire, on 12 February 1809, at his family's home, The Mount. He was the fifth of six children of wealthy society doctor and financier Robert Darwin and Susannah Darwin (*née* Wedgwood). His grandfathers Erasmus Darwin and Josiah Wedgwood were both prominent abolitionists. Erasmus Darwin had praised general concepts of evolution and common descent in his *Zoonomia* (1794), a poetic fantasy of gradual creation including undeveloped ideas anticipating concepts his grandson expanded.
A chalk drawing of the seven-year-old Darwin in 1816, with a potted plant, by Ellen Sharples
Both families were largely Unitarian, though the Wedgwoods were adopting Anglicanism. Robert Darwin, himself quietly a freethinker, had baby Charles baptised in November 1809 in the Anglican St Chad's Church, Shrewsbury, but Charles and his siblings attended the Unitarian chapel with their mother. The eight-year-old Charles already had a taste for natural history and collecting when he joined the day school run by its preacher in 1817. That July, his mother died. From September 1818, he joined his older brother Erasmus in attending the nearby Anglican Shrewsbury School as a boarder.

Darwin spent the summer of 1825 as an apprentice doctor, helping his father treat the poor of Shropshire, before going to the well regarded University of Edinburgh Medical School with his brother Erasmus in October 1825. Darwin found lectures dull and surgery distressing, so he neglected his studies. He learned taxidermy in around 40 daily hour-long sessions from John Edmonstone, a freed black slave who had accompanied Charles Waterton in the South American rainforest.

In Darwin's second year at the university, he joined the Plinian Society, a student natural-history group featuring lively debates in which radical democraticstudents with materialistic views challenged orthodox religious concepts of science. He assisted Robert Edmond Grant's investigations of the anatomy and life cycle of marine invertebrates in the Firth of Forth, and on 27 March 1827 presented at the Plinian his own discovery that black spores found in oyster shells were the eggs of a skate leech. One day, Grant praised Lamarck's evolutionary ideas. Darwin was astonished by Grant's audacity, but had recently read similar ideas in his grandfather Erasmus' journals. Darwin was rather bored by Robert Jameson's natural-history course, which covered geology—including the debate between Neptunism and Plutonism. He learned the classification of plants, and assisted with work on the collections of the University Museum, one of the largest museums in Europe at the time.

Darwin's neglect of medical studies annoyed his father, who shrewdly sent him to Christ's College, Cambridge, to study for a Bachelor of Arts degree as the first step towards becoming an Anglican country parson. As Darwin was unqualified for the *Tripos*, he joined the *ordinary* degree course in January 1828. He preferred riding and shootingto studying.
Bicentennial portrait by Anthony Smith of Darwin as a student, in the courtyard at Christ's College, Cambridgewhere he had rooms

During the first few months of Darwin's enrollment at Christ's College, his second cousin William Darwin Fox was still studying there. Fox impressed him with his butterfly collection, introducing Darwin to entomology and influencing him to pursue beetle collecting. He did this zealously, and had some of his finds published in James Francis Stephens' *Illustrations of British entomology* (1829–32).

Through Fox, Darwin became a close friend and follower of botany professor John Stevens Henslow. He met other leading parson-naturalists who saw scientific work as religious natural theology, becoming known to these dons as "the man who walks with Henslow". When his own exams drew near, Darwin applied himself to his studies and was delighted by the language and logic of William Paley's *Evidences of Christianity* (1795). In his final examination in January 1831 Darwin did well, coming tenth out of 178 candidates for the *ordinary* degree.

Darwin had to stay at Cambridge until June 1831. He studied Paley's *Natural Theology or Evidences of the Existence and Attributes of the Deity* (first published in 1802), which made an argument for divine design in nature, explaining adaptation as God acting through laws of nature. He read John Herschel's new book, *Preliminary Discourse on the Study of Natural Philosophy* (1831), which described the highest aim of natural philosophy as understanding such laws through inductive reasoning based on observation, and Alexander von Humboldt's *Personal Narrative* of scientific travels in 1799–1804. Inspired with "a burning zeal" to contribute, Darwin planned to visit Tenerife with some classmates after graduation to study natural history in the tropics. In preparation, he joined Adam Sedgwick's geology course, then on 4 August travelled with him to spend a fortnight mapping strata in Wales.

### Survey voyage on HMS *Beagle*

Further information: Second voyage of HMS Beagle
The round-the-world voyage of the *Beagle*, 1831–1836

After leaving Sedgwick in Wales, Darwin spent a few days with student friends at Barmouth. He returned home on 29 August to find a letter from Henslow proposing him as a suitable (if unfinished) naturalist for a self-funded supernumeraryplace on HMS *Beagle* with captain Robert FitzRoy, a position for a gentleman rather than "a mere collector". The ship was to leave in four weeks on an expedition to chart the coastline of South America. Robert Darwin objected to his son's planned two-year voyage, regarding it as a waste of time, but was persuaded by his brother-in-law, Josiah Wedgwood II, to agree to (and fund) his son's participation. Darwin took care to remain in a private capacity to retain control over his collection, intending it for a major scientific institution.

After delays, the voyage began on 27 December 1831; it lasted almost five years. As FitzRoy had intended, Darwin spent most of that time on land investigating geology and making natural history collections, while HMS *Beagle* surveyed and charted coasts. He kept careful notes of his observations and theoretical speculations, and at intervals during the voyage his specimens were sent to Cambridge together with letters including a copy of his journal for his family. He had some expertise in geology, beetle collecting and dissecting marine invertebrates, but in all other areas was a novice and ably collected specimens for expert appraisal. Despite suffering badly from seasickness, Darwin wrote copious notes while on board the ship. Most of his zoology notes are about marine invertebrates, starting with plankton collected during a calm spell.
Darwin (right) on the *Beagle*'s deck at Bahía Blancain Argentina, with fossils; caricature by Augustus Earle, the initial ship's artist.

On their first stop ashore at St Jago in Cape Verde, Darwin found that a white band high in the volcanic rock cliffs included seashells. FitzRoy had given him the first volume of Charles Lyell's *Principles of Geology*, which set out uniformitarian concepts of land slowly rising or falling over immense periods, and Darwin saw things Lyell's way, theorising and thinking of writing a book on geology. When they reached Brazil, Darwin was delighted by the tropical forest, but detested the sight of slavery, and disputed this issue with Fitzroy.

The survey continued to the south in Patagonia. They stopped at Bahía Blanca, and in cliffs near Punta Alta Darwin made a major find of fossil bones of huge extinct mammals beside modern seashells, indicating recent extinction with no signs of change in climate or catastrophe. He found bony plates like a giant version of the armour on local armadillos. From a jaw and tooth he identified the gigantic *Megatherium*, then from Cuvier's description thought the armour was from this animal. The finds were shipped to England, and scientists found the fossils of great interest.

On rides with gauchos into the interior to explore geology and collect more fossils, Darwin gained social, political and anthropological insights into both native and colonial people at a time of revolution, and learnt that two types of rhea had separate but overlapping territories. Further south, he saw stepped plains of shingle and seashells as raised beaches at a series of elevations. He read Lyell's second volume and accepted its view of "centres of creation" of species, but his discoveries and theorising challenged Lyell's ideas of smooth continuity and of extinction of species.

Three Fuegians on board, who had been seized during the first *Beagle* voyage then given Christian education in England, were returning with a missionary. Darwin found them friendly and civilised, yet at Tierra del Fuego he met "miserable, degraded savages", as different as wild from domesticated animals. He remained convinced that, despite this diversity, all humans were interrelated with a shared origin and potential for improvement towards civilisation. Unlike his scientist friends, he now thought there was no unbridgeable gap between humans and animals. A year on, the mission had been abandoned. The Fuegian they had named Jemmy Button lived like the other natives, had a wife, and had no wish to return to England.
As HMS *Beagle* surveyed the coasts of South America, Darwin theorised about geology and the extinction of giant mammals. Watercolour by the ship's artist Conrad Martens, who replaced Augustus Earle, in Tierra del Fuego.

Darwin experienced an earthquake in Chile in 1835 and saw signs that the land had just been raised, including mussel-beds stranded above high tide. High in the Andes he saw seashells, and several fossil trees that had grown on a sand beach. He theorised that as the land rose, oceanic islands sank, and coral reefsround them grew to form atolls.

On the geologically new Galápagos Islands, Darwin looked for evidence attaching wildlife to an older "centre of creation", and found mockingbirds allied to those in Chile but differing from island to island. He heard that slight variations in the shape of tortoise shells showed which island they came from, but failed to collect them, even after eating tortoises taken on board as food. In Australia, the marsupialrat-kangaroo and the platypus seemed so unusual that Darwin thought it was almost as though two distinct Creators had been at work.He found the Aborigines "good-humoured & pleasant", their numbers depleted by European settlement.

FitzRoy investigated how the atolls of the Cocos (Keeling) Islands had formed, and the survey supported Darwin's theorising. FitzRoy began writing the official *Narrative* of the *Beagle* voyages, and after reading Darwin's diary he proposed incorporating it into the account.Darwin's *Journal* was eventually rewritten as a separate third volume, on geology and natural history.

In Cape Town, South Africa, Darwin and FitzRoy met John Herschel, who had recently written to Lyell praising his uniformitarianism as opening bold speculation on "that mystery of mysteries, the replacement of extinct species by others" as "a natural in contradistinction to a miraculous process". When organising his notes as the ship sailed home, Darwin wrote that, if his growing suspicions about the mockingbirds, the tortoises and the Falkland Islands fox were correct, "such facts undermine the stability of Species", then cautiously added "would" before "undermine". He later wrote that such facts "seemed to me to throw some light on the origin of species".

Without telling Darwin, extracts from his letters to Henslow had been read to scientific societies, printed as a pamphlet for private distribution among members of the Cambridge Philosophical Society, and reported in magazines, including *The Athenaeum*. Darwin first heard of this at Cape Town, and at Ascension Island read of Sedgwick's prediction that Darwin "will have a great name among the Naturalists of Europe".