Alfred Russel Wallace (1823-1913) was a British naturalist, explorer, geographer, anthropologist and biologist. He is best known for independently proposing a theory of evolution due to natural selection that prompted Charles Darwin to publish his own theory. He was considered the 19th century's leading expert on the geographical distribution of animal species and is sometimes called the "father of biogeography". Wallace was one of the leading evolutionary thinkers of the 19th century and made a number of other contributions to the development of evolutionary theory besides being co-discoverer of natural selection.