Charles Darwin, naturalist, geologist and originator of the theory of natural selection, was educated at the University of Edinburgh (1825-1827) and at Christ's College, Cambridge (to 1831). He first studied medicine, but had no aptitude for it, and a career in the church did not appeal to him either. However, natural history did interest him and when H.M.S. Beagle, commanded by Captain Fitzroy, was about to depart on a voyage of scientific exploration to South America in 1831 he accepted the position of ship's naturalist. The voyage lasted five years, during which Darwin made extensive zoological and geological observations which formed the basis of some of his later writings.
On the return journey to England the Beagle anchored at Simon's Town from 31 May to 18 June 1836, mainly to check their chronometers at the Royal Obsevatory, Cape of Good Hope. Darwin met Sir John Herschel* in Cape Town and on 4 June set out on a short excursion with a local guide. He first travelled to Paarl, where he climbed Paarl Mountain (4 June); proceeded to Franschhoek and crossed the Franschoek Pass (5 June); turned south to join the road between Caledon and Cape Town, and followed this road to near the top of Sir Lowry's Pass (6 June); then descended the pass and returned to Cape Town (7 June). The ship's departure was delayed by bad weather, allowing Darwin time to meet Dr. Andrew Smith*, Thomas Maclear* and Captain James E. Alexander*. Andrew Smith showed him the contact between the Cape granite and overlying shale at Sea Point, described earlier by Clarke Abel*. Darwin described the exposure at Green Point in some detail, noting that the thin, isolated beds of shale which occur as if floating in the granite near the contact, are quite compatible with the view that the granite was injected into the shale while liquid. He also described how the shale was metamorphosed into gneiss in places along the contact, as well as the appearence of the Table Mountain sandstone. His description was published in Geological observations on the volcanic islands visited during the voyage of H.M.S. Beagle, together with some brief notes on the geology of Australia and the Cape of Good Hope (London, 1844).
Darwin's Journal of researches into the geology and natural history of the various countries visited by H.M.S. Beagle... from 1832 to 1836 appeared in print in 1839 and established his reputation as a naturalist. The book refers to observations on the abundance of game and the scarcity of vegetation, made by Andrew Smith during his expedition into the interior of South Africa. Darwin used these observations, with those made by William Burchell* and other travellers, to conclude that there is no close relationship between the quantity of vegetation found in a region and the size of the mammals that it supports. He subsequently used this conclusion to argue against the view that extinctions of large animals were caused by catastrophic changes in climate. However, he remarked in his Journal that he found little worth seeing at the Cape, perhaps because he was by then tired of travelling and had no time to see much of the interior.
During the first few days after leaving Simon's Town Captain Fitzroy and Darwin, responding to what they perceived as a strong feeling against missionaries at the Cape, wrote "A letter, containing remarks on the moral state of Tahiti, New Zealand, etc.", in which they argued that Christian missionaries played an important role in uplifting, devoloping and enriching the lives of people all over the world. The letter was published in Cape Town in the South African Christian Recorder (Vol. 2(4), pp. 311-343) in September 1836, and appears to be Darwin's first publication.
After his return to England in 1836 Darwin settled down there for the rest of his life. He was a painstaking perfectionist who collected and classified masses of information. Among his contributions to science was a new theory of the formation of coral reefs, proposed in his Journal of researches..., which was widely accepted. His second book, The zoology of the Voyage of H.M.S. Beagle, was published in 1839-1842. In 1842 he wrote a 35 page draft of his ideas on evolution, followed by a 230 page draft in 1844, but these were not intended for publication. For years he remained engaged on a major work dealing with natural variation and evolution; however, the announcement of a theory of evolution by A.R. Wallace in 1858 led him to abandon this project in favour of a shorter, now famous book, On the origin of species by means of natural selection..., published in 1859. This epoch-making work started a controversy, particularly among those with religious views, that lasted for generations. Many of his observations and ideas had been written about, piecemeal, by other naturalists, but he contributed two notable things: An overwhelming amount of evidence in support of evolution, and a plausible explanation of how evolution had occurred - through natural selection. His theory of evolution was first applied to explain human origins by the geologist Charles Lyell. Darwin supported his views and in 1871 published The descent of man, and selection in relation to sex, in which he discussed the evolution of humans from earlier primates. He also produced many other works on zoology, botany, and geology, in several of which he applied and extended his theory of evolution.
Darwin was ill for most of his life and was obsessively preoccupied with his physical and mental health. He has been described as "A delicate, neurotic Englishman who had given the world a theory which decisively changed the thinking of the day" (Tobias, 1982).