Mechanism of Evolution

Ø Darwin did not quite explain how evolution gave rise to different species of the same organism.

Ø Mendel mentioned about inheritable factors, which influenced the phenotype of an organism.

Ø Hugo de Vries based on his work on evening primrose suggested that variations occurred due to mutations.

Ø Mutations are random and directionless while the variations that Darwin talked about were small and directional. Hugo de Vries gave the name saltation (single step large mutation) to the mutations which brought about speciation.