Answer:
(I) Lamarckism or Theory of Inheritance of Acquired characters.
This theory is based on the comparison between the contemporary species of Jean Baptiste de Lamarck's time to fossil records.
(II) Darwinism or Theory of Natural Selection.
Charles Darwin made an extensive study of nature for over 20 years, especially in 1831-1836 when he went on a voyage on the famous ship “H.M.S. Beagle” and explored South America, the Galapagos Islands and other islands.
(III) Mutation theory of De Vries.
The mutation theory of evolution was proposed by a Dutch botanist, Hugo de Vries (1848-1935 A.D.) in 1901 A.D. in his book entitled “Species and Varieties, Their Origin by Mutation”. He worked on evening primrose (Oenothera lamarckiana).
(IV) Neo-Darwinism or Modern concept or Synthetic theory of evolution.
The detailed studies of Lamarckism, Darwinism and Mutation theory of evolution showed that no single theory is fully satisfactory. Neo-Darwinism is a modified version of theory of Natural Selection and is a sort of reconciliation between Darwin’s and de Vries theories.
