Which of the following statements are true about the work done by Hug…

The correct answer is Option (1) → (B) and (D) only

Hugo de Vries worked on the evening primrose and gave the idea of mutation, a large difference that appears suddenly in a population. He believed that evolution is caused by mutation, not by the small variations Darwin talked about. Since one large mutation could form a new species in a single step, he called it saltation.

(A) According to him the evolution was gradual and variations were small and directional. — Incorrect. This was Darwin’s view. For de Vries, mutations are random and directionless, and a new species can form in one step.

(B) Hugo deVries worked on evening primrose. — Correct. His idea of mutation came from his work on the evening primrose.

(C) He brought forth the idea of Natural selection. — Incorrect. Natural selection was the idea of Darwin (and Wallace). De Vries brought forth the idea of mutation.

(D) He believed that mutation caused speciation. — Correct. He believed that a single-step large mutation (saltation) caused speciation.

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).”