Charles Robert Darwin (12 February 1809 – 19 April 1882) was an English naturalist, who proposed and provided evidence for the scientific theory that all species have evolved over time from one or a few common ancestors, through the process of natural selection. This theory became widely accepted by the scientific community in the 1930s,and now forms the basis of modern evolutionary theory. In modified form, Darwin's theory remains a cornerstone of biology, as it provides a unifying explanation for the diversity of life.
Darwin developed his interest in natural history at Edinburgh University while studying first medicine, then theology. His five-year voyage on the Beagle established him as a geologist whose observations and theories supported Charles Lyell's uniformitarian ideas, 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 investigated the transmutation of species and conceived his theory of natural selection in 1838. Having seen others attacked as heretics for such ideas, he confided only in his closest friends and continued his extensive research to meet anticipated objections. In 1858, Alfred Russell Wallace sent him an essay describing a similar theory, causing the two to publish their theories early in a joint publication.
His 1859 book On the Origin of Species established evolution by common descent as the dominant scientific explanation of diversification in nature. 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. His research on plants was published in a series of books, and in his final book, he examined earthworms and their effect on soil