. . Lamarck’s theory Jean Baptiste de Lamarck, was the first to postulate the theory of evolution in his famous book ‘ Philosophie Zoologique ’ in the year . The two principles of Lamarckian theory are: i.
The theory of use and disuse - Organs that are used often will increase in size and those that are not used will degenerate. Neck in giraffe is an example of use and absence of limbs in snakes is an example for disuse theory. ii. The theory of inheritance of acquired characters - Characters that are developed during the life time of an organism are called acquired characters and these are then inherited.