Define the following with one example for each :
(i) Genetic Drift.
(ii) Natural selection.
(iii) Reproductive isolation.

Explanation

(i) Genetic drift : It refers to the random change in gene frequencies in a small population, presumably owing to change rather than natural selection, thereby providing diversity without any adaptations.
(ii) Natural selection : In this new suitable traits are selected to live in the prevailing environment.
(iii) Reproductive isolation : When same members of a particular species are not able to mate with other members of the same species due to environmental barriers or due to other geographical barriers , it is known as reproductive isolation.