Question

Which of the following is the correct option?

• A. De Vries believed that evolution is caused by mutation while Darwin believed that evolution is not caused by minor inheritable variations
• B. According to de Vries, mutations are not random while according to Darwin, random mutations lead to evolution
• C. Mutations are directional as per deVries but variations are directionless according to Darwin
• D. Saltation causes evolution as per deVries while evolution is gradual according to Darwin

Answer 1

The correct option is D Saltation causes evolution as per deVries while evolution is gradual according to Darwin

Biological evolution refers to the gradual changes that occur in the inheritable characters of organisms over several generations. Both Hugo de Vries and Darwin had different views on evolution and its mechanism. The given table gives a comparative account of their beliefs:

Hugo de Vries	Charles Darwin
He believed that random, large and discrete inheritable mutations called saltation lead to development of a new species in a single generation.	Darwin states that new variations appear in every generation and such small variations accumulate over several generations by natural selection until the offspring become significantly different, thus evolving into a new species.
According to de Vries, mutations can occur at any time, hence are random and can be useful, harmful or have no effects at all on the organisms, hence are directionless.	Darwin believed that the small variations accumulate over generations and nature selects the useful variations, hence variations are directional.
Hugo de Vries believed that evolution is a sudden process and due to a single step mutation.	Darwin believed that evolution is a gradual process and occurs over a course of several generations.