How do mutations differ from Darwinian variations according to Hugo d…

The correct answer is Option (2) → Mutations are random and directionless, while Darwinian variations are small and directional.

Hugo de Vries, working on evening primrose, saw large differences arising suddenly in a population and called them mutations. He set them against the small heritable variations that Darwin had described.

Option (1) Mutations are small and directional, while Darwinian variations are large and sudden. — Incorrect. This reverses the two. Mutations are large and sudden, while Darwinian variations are small.

Option (2) Mutations are random and directionless, while Darwinian variations are small and directional. — Correct. Mutations are random and directionless, while Darwinian variations are small and directional.

Option (3) Mutations occur only in certain species, while Darwinian variations occur in all species. — Incorrect. NCERT does not limit mutations to certain species; the contrast it draws is about size and direction.

Option (4) Mutations are influenced by natural selection, while Darwinian variations are not. — Incorrect. De Vries held that mutation, not natural selection acting on small variations, causes evolution. The difference he drew was about the nature of the change, not which one selection acts on.

NCERT Extract:
Mechanism of Evolution – “… In the first decade of twentieth century, Hugo deVries based on his work on evening primrose brought forth the idea of mutations – large difference arising suddenly in a population. He believed that it is mutation which causes evolution and not the minor variations (heritable) that Darwin talked about. Mutations are random and directionless while Darwinian variations are small and directional. Evolution for Darwin was gradual while deVries believed mutation caused speciation and hence called it saltation (single step large mutation).”