Write short note on Lamarckism.
 

- Lamark in his book 'Philosophic Zoologique' ($1809$) proposed that the evolution of life forms had occurred by the use and disuse of organs.

- He gave the example of giraffes, which initially did not have long necks.

- But, due to sudden disappearance of surface vegetation they had to stretch their neck in order to reach the leaves on tall trees.

So they got adapted to this situation by elongation of their necks.

By passing this acquired character to succeeding generation over the years they came to acquire long neck.

This theory also called as Lamarckism is no more accepted now.

- August Weismann offered greatest opposition to his theory of inheritance of acquired characters and put forward this theory of continuity of germplasm in $1892$ .