Question

Who disproved Lamarckism and how?

Answer 1

German biologist August Weismann (in the 1880s) disapproved Lamarckism by formulating the germ-plasm theory of inheritance.

1. Weismann reasoned that reproductive cells (germ cells) were separate from the functional body cells (soma or somatic cells). Hence, changes to the somatic cells would not affect the germ-plasm and would not be passed on to the offspring.
   
2. In order to prove that the misuse or loss of somatic structures would not affect the subsequent offspring, he removed the tails of mice and then allowed them to breed.
   
3. After twenty generations of this experimental protocol, he found that mice still grew tails of the same length as those who had never been manipulated.