Question

when birds migrate in to or out of a defined population and mate with birds from another population the existing pool of genes may be altered migration can increase or decrease gene frequencies in population resulting in...

Answer 1

Answer: These genes will mix and the population will increase.

Explanation:

This is beside the point though, this will make both groups of birds join forces. resulting in overpopulation.

Answer 2

Evolution is defined as genetic changes in a population over multiple generations. A(n) ____ does not evolve because allele do not change; however, a(n) ____ can evolve because allele frequencies can change