Which one of the given terms states that mutations caused speciation?

The correct answer is Option (4) → Saltation

Hugo de Vries held that evolution is caused by mutations, which are large and random changes. He believed that a mutation could produce a new species in a single step, and he called this saltation (single step large mutation). Darwin thought differently. For him, evolution was gradual and worked on small, directional variations.

(1) Variation — Incorrect. Variation is the difference between individuals. Darwin’s small, directional variations built up slowly, and they are not the idea that mutation caused speciation.

(2) Genetic recombination — Incorrect. It is the shuffling of existing genes during sexual reproduction. It makes no new gene.

(3) Gene migration — Incorrect. It is the movement of genes from one population to another. It changes allele frequencies and is not a mutation.

(4) Saltation — Correct. It is the term for speciation by a single-step mutation.

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).”