The English naturalist Charles Robert Darwin (1809-1882) discovered that natural selection was the agent for the transmutation of organisms during evolution, as did Alfred Russel Wallace independently. Darwin presented his theory in "Origin of Species."
The concept of evolution by descent dates at least from classical Greek philosophers. In the 18th century Carl Linnaeus postulated limited mutability of species by descent and hybridization. Charles Darwin's grandfather, Erasmus Darwin, and the Chevalier de Lamarck were the chief proponents of evolution about 1800. Such advocacy had little impact on the majority of naturalists, concerned to identify species, the stability of which was considered essential for their work. Natural theology regarded the perfection of adaptation between structure and mode of life in organisms as evidence for a beneficent, all-seeing, all-planning Creator. Organic structure, planned in advance for a preordained niche, was unchanged from the moment of creation. Variations in structure in these earthly imperfect versions of the Creator's idea were minor and impermanent.
In 1815 William Smith had demonstrated a sequence of fossil populations in time. Charles Lyell, adopting James Hutton's uniformitarian view that present conditions and processes were clues to the past history of the earth, wrote his Principles of Geology (1830-1833), which Darwin on his Beagle circumnavigation found most apt for his own geological observations. Fossils in South America and apparent anomalies of animal distribution triggered the task for Darwin of assembling a vast range of material. A reading of Thomas Malthus's Essay on the Principle of Population in 1838 completed Darwin's conceptual scheme.
Critics, for whom the Origin is paramount among Darwin's considerable output, have accused him of vacillation and procrastination. But recent study of unpublished manuscripts and his entire works reveal a continuity of purpose and integrity of effort to establish the high probability of the genetic relationship through descent in all forms of life. Man is dethroned as the summit of creation and as the especial concern of the Creator. This revolution in thought has had an effect on every kind of human activity.
Darwin was born on Feb. 12, 1809, at Shrewsbury, the fifth child of Robert and Susannah Darwin. His mother, who was the daughter of the famous potter Josiah Wedgwood, died when Charles was 8, and he was reared by his sisters. At the age of 9 Charles entered Shrewsbury School. His record was not outstanding, but he did learn to use English with precision and to delight in Shakespeare and Milton.
In 1825 Darwin went to Edinburgh University to study medicine. He found anatomy and materia medica dull and surgery unendurable. In 1828 he entered Christ's College, Cambridge, with the idea of taking Anglican orders. He attended John Stevens Henslow's course in botany, started a collection of beetles that became famous, and read widely. William Paley's Natural Theology (1802) delighted Darwin by its clear logical presentation, and he later regarded this study as the most worthwhile benefit from Cambridge. He received his bachelor's degree in 1831.
On Henslow's recommendation Darwin was offered the position of naturalist for the second voyage of H. M. S. Beagle to survey the coast of Patagonia and Tierra del Fuego and complete observations of longitude by circumnavigation with a formidable array of chronometers. The Beagle left on Dec. 27, 1831, and returned on Oct. 2, 1836. During the voyage Darwin spent 535 days at sea and roughly 1200 on land. Enough identification of strata could be done on the spot, but sufficiently accurate identification of living organisms required systematists accessible only in London and Paris.
Darwin kept his field observations in notebooks with the specimens listed serially and their place and time of collection documented. On July 24, 1834, he wrote: "My notes are becoming bulky. I have about 600 small quarto pages full; about half of this is Geology the other imperfect descriptions of animals; with the latter I make it a rule to describe those parts which cannot be seen in specimens in spirits. I keep my private Journal distinct from the above." Toward the end of the voyage, when sea passages were long, he copied his notes and arranged them to accord with systematics, concentrating on range and habits. Geology was prepared with fewer inhibitions; he wrote from Mauritius in April 1836: "It is a rare piece of good fortune for me that of the many errant (in ships) Naturalists there have been few, or rather no, Geologists. I shall enter the field unopposed."
During the trip Darwin discovered the relevance of Lyell's uniformitarian views to the structure of St. Jago (Cape Verde Islands). He found that small locally living forms closely resembled large terrestrial fossil mammals embedded between marine shell layers and that the local sea was populated with living occupants of similar shells. He also observed the overlapping distribution on the continuous Patagonian plain of two closely related but distinct species of ostrich. An excursion along the Santa Cruz river revealed a section of strata across South America. He observed the differences between species of birds and animals on the Galápagos Islands.
Darwin's Journal of Researches was published in 1839. With the help of a government grant toward the cost of the illustrations, the Zoology of the Voyage of the Beagle was published, in five quarto volumes, from 1839 to 1843. Specialist systematists wrote on fossil and living mammals, birds, fish, and reptiles. Darwin edited the work and contributed habits and ranges of the animals and geological notes on the fossils. Two themes run through his valuable and mostly neglected notes: distribution in space and time and observations of behavior as an aid to species diagnosis. He also published The Structure and Distribution of Coral Reefs (1842); he had studied the coral reefs in the Cocos Islands during the Beagle voyage.
Darwin abandoned the idea of fixity of species in 1837 while writing his Journal. A second edition, in 1845, had a stronger tinge of transmutation, but there was still no public avowal of the new faith. This delightful volume is his most popular and accessible work.
Darwin's Transmutation (Species) Notebooks (1837-1839) have recently been reconstructed. The notion of "selection owing to struggle" derived from his reading of Malthus in 1838. Earlier Darwin had read Pyrame de Candolle's works on plant geography, so his mind was receptive. The breadth of interest and profusion of hypotheses characteristic of Darwin, who could carry several topics in his mind at the same time, inform the whole. From this medley of facts allegedly assembled on Baconian principles all his later works derive.
It was not until Darwin's geological observations of South America were published in 1846 that he started a paper on his "first Cirripede," a shell-boring aberrant barnacle, no bigger than a pin's head, he had found at Chonos Island in 1835. This was watched while living, then dissected, and drawn while the Beagle sheltered from a week of severe storms. The working out of the relationship to other barnacles forced him to study all barnacles, a task that occupied him until 1854 and resulted in two volumes on living forms and two on fossil forms.
Darwin married Emma Wedgwood, his first cousin, in 1839. They lived in London until 1842, when ill health drove him to Down House, where he passed the rest of his life in seclusion. Four of their sons became prominent scientists: George was an astronomer and mathematician, Francis a botanist, Leonard a eugenist, and Horace a civil engineer.
In 1842 and 1844 Darwin wrote short accounts of his transmutation views. The 1844 sketch in corrected fair copy was a testament accompanied by a letter to his wife to secure publication should he die. Late in 1844 Robert Chambers's Vestiges of Creation appeared advocating universal development by descent. A great scandal ensued, and criticism of the amateur pretensions of the author was savage. Darwin decided to bide his time and become more proficient as a biologist.
In 1855 Darwin began to study the practices of poultry and pigeon fanciers and worldwide domesticated breeds, conducted experiments on plant and animal variation and its hereditary transmission, and worried about the problem of plant and animal transport across land and water barriers, for he was persuaded of the importance of isolation for speciation. The last step in his conceptual scheme had already occurred to him in 1852 while pondering Henri Milne-Edwards's concept of diversification into specialized organs for separation of physiological functions in higher organisms and the relevance of these considerations for classification when related to the facts of embryological development. Darwin's "principle of divergence" recognizes that the dominant species must make more effective use of the territory it invades than a competing species and accordingly it becomes adapted to more diversified environments.
In May 1856 Lyell heard of Darwin's transmutation hypothesis and urged him to write an account with full references. Darwin sent the chapter on distribution to Lyell and Sir Joseph Hooker, who were deeply impressed. Darwin continued his writing, and on June 14, 1858, when he was halfway through, he received an essay from Alfred Russel Wallace containing the theory of evolution by natural selection—the same theory Darwin was working on. Lyell and Hooker arranged for a reading of a joint paper by Wallace and Darwin, and it was presented at a meeting of the Linnaean Society on July 1. The paper had little effect.
On Nov. 24, 1859, Darwin published On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life. The analogy of natural selection was prone to misunderstanding by readers, since it carried for them an implied purpose on the part of a "deified" Nature. Herbert Spencer's phrase "survival of the fittest" was equally misleading because the essence of Darwin's theory is that, unlike natural theology, adaptation must not be too perfect and rigid. A mutable store of variation must be available to any viable population in nature.
The publication of Darwin's book secured worldwide attention for his hypothesis and aroused impassioned controversy. His main champion was T. H. Huxley. Darwin, remote in his retreat at Down House, took painstaking note of criticism and endeavored to answer points of detail in the five more editions of Origin produced during his lifetime. He avoided trouble and made several unfortunate concessions which weakened his presentation and made his views seem vague and hesitant. The first edition is easily the best.
In On the Various Contrivances by Which British and Foreign Orchids Are Fertilised by Insects (1862) Darwin showed how the welfare of an organism may be hidden in apparently unimportant peculiarities. It became hard to say what is "useless" in nature. His The Variation of Animals and Plants under Domestication (1868; rev. ed. 1875) expanded on a topic he had introduced in Origin. A chapter in Origin on man as the most domesticated of animals grew into the book The Descent of Man and Selection in Relation to Sex (1871). The Expression of the Emotions in Man and Animals (1872) developed from material squeezed out of the Descent.
Plants became an increasing preoccupation, the more so since Darwin had his son Francis as collaborator and amanuensis. Papers Darwin had published in 1864 were collected into The Movements and Habits of Climbing Plants (1875), and these ideas were further generalized on uniformitarian lines and published as The Power of Movement in Plants (1880). All plants, not merely climbing ones, were shown to execute to some degree exploratory "circumnutation" movements. Studies on fertilization of plants by insects recorded as early as 1840 led to The Effects of Cross and Self-Fertilisation in the Vegetable Kingdom (1876) and The Different Forms of Flowers on Plants of the Same Species (1877). Insectivorous Plants (1873) pursued the reactions of plants to stimuli. Darwin's last work returned to observations he had made in 1837: The Formation of Vegetable Mould through the Action of Worms, with Observations on Their Habits (1881). He died on April 19, 1882, and was buried in Westminster Abbey.
Primary sources on Darwin include The Life and Letters of Charles Darwin, edited by Francis Darwin (3 vols., 1887), which has an autobiographical chapter; More Letters of Charles Darwin, edited by Francis Darwin and A. C. Seward (1903); and his Autobiography, edited with appendix and notes by his granddaughter, Nora Barlow (1958; repr. 1969). An excellent, nontechnical account of Darwin's life and work is Sir Gavin de Beer, Charles Darwin: Evolution by Natural Selection (1964). Other biographical studies are Paul B. Sears, Charles Darwin: The Naturalist as a Cultural Force (1950), and Gerhard Wichler, Charles Darwin: The Founder of the Theory of Evolution and Natural Selection (1961). Gertrude Himmelfarb, Darwin and the Darwinian Revolution (1959), offers a provocative reinterpretation of the man and his impact.
A dramatic pictorial account of Darwin's trip around the world in the Beagle is Alan Moorehead, Darwin and the Beagle (1969), which incorporates excerpts from Darwin's autobiography, journal, and letters. Parts of Darwin's work are examined in P. R. Bell, ed., Darwin's Biological Work: Some Aspects Reconsidered (1959), and Darwin's vast influence is assessed in Michael T. Ghiselin, The Triumph of the Darwinian Method (1969). A good, succinct presentation of the essence of Darwin's ideas is Benjamin Farrington, What Darwin Really Said (1967), which can serve as a review of the major problems raised by Darwin's theories.