Describe the role of variation in evolution.

In the presence of variation, organisms respond to change in different ways.

– In presence of a selection pressure, organisms which are more suitably adapted i.e. with favorable variations, survive and reproduce while organism with unfavourable variations die and may be weeded out. As a result, a new strain of organisms with favorable variations arises.

– Also certain variation may limit successful sexual reproduction among organisms of a population. As a result, the population may be split into two differently intern-breeding populations which may later evolve into a new species of organisms.

– Some variations may be so lethal; that organisms containing them do not survive to the next generations, even without a selection pressure. As a result, such organisms become extinct in the subsequent generations, leaving a strain of organisms with non-lethal variations.