Target Exam

CUET

Subject

Biology

Chapter

Evolution

Question:

How do mutations differ from Darwinian variations according to Hugo de Vries?

Options:

Mutations are small and directional, while Darwinian variations are large and sudden.

Mutations are random and directionless, while Darwinian variations are small and directional.

Mutations occur only in certain species, while Darwinian variations occur in all species.

Mutations are influenced by natural selection, while Darwinian variations are not.

Correct Answer:

Mutations are random and directionless, while Darwinian variations are small and directional.

Explanation:

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

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). Studies in population genetics, later, brought out some clarity.