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...