Sometimes two phenotypically different populations interbreed to a limited extent, so that it is difficult to determine whether they are clearly separate species. This is not a concern to scientists because this .

This is not a concern to scientists because this is an indication that a new species may be formed or in progress from the interbreeding.

Explanation:

We know that species are the populations that can mate to produce fertile and viable progeny.  Speciation occurs when new species is form by a population which has separated and become reproductively isolated.

The two dogs living in Africa and America can mate and produce healthy offsprings and they are phenotypically different.

The mating of horse and donkey are different species because they produce infertile mule.

When two population of species that are phenotypically different mate they have overcome the mechanism of reproductive isolation.

mammal

explanation: