THEORY OF NATURAL SELECTION OR DARWINISM

• Theory of CharIes Darwin (1809 - 1882) about evolution marks the beginning of an era in understanding of evolution.
• At the age of 22 he led the expedition tour on H.M.S.Beagle (1831), studied variety of flora and fauna from different parts of globe, but found Galapagos Island most interesting, a "living laboratory of evolution".
• Earlier a believer of "theory of special creation", Darwin propounded Natural Selection as basis of evolution and all organisms including man have arisen as modified descendants.
• He was influenced by the ideas of

(i)         T.R. Malthus (1799)                    -          An Essay on Population

(ii)        Charles Lyell (1832)                  -          Principles of Geology

(iii)       Herbert Spencer (1856)              -          Idea of Survival of fittest

• Later with the help of Lyell and Hooker Darwin published (1859) his complete book "Origin of New Species by Natural Selection" : "The Preservation of Races in the Struggle for Life".
• Alfred Russel Wallace (1823 - 19130) investigated the flora and fauna of South East Asia and South America.
• He came to conclusion which was supported by Darwin in the paper "On the tendency of varieties to depart independently from the original type."
• Darwin and Wallace therefore produced a joint proper "On the tendency of species to fonn varieties and perpetua- tion of varieties and species and mans of natural selection."
• In 1859, Darwin explained the theory of evolution in the back "On the origin of species by means of natural selection" popularly called origin of species.
• The origin of species (1859) holds an impressive amount of evidences in support of evolution by natural selection.