Question

How do species of two isolated subpopulations become two different species?

Answer 1

When two sub species get isolated they will have new variations in them to adapt themselves to the new environment. So these variation sget accumulated over generations and at one generation both the sub species will not be able to interbreed.Then there will be a formation of new species.

Answer 2

When two sub species get isolated they will have new variations in them to adapt themselves to the new environment. So these variation sget accumulated over generations and at one generation both the sub species will not be able to interbreed.Then there will be a formation of new species.