Answer:
Biogeographic isolation causes changes in gene pools that result from populations being separated.
Step-by-step explanation:
Biogeographical isolation consists in the separation of a population by a geographical barrier, giving rise to subpopulations.
With isolation, the subpopulations start to suffer different pressures from the environment and consequently the selected genes in one subpopulation will be different from the other subpopulation.
Due to the biogeographic isolation, the two subpopulations will be prevented from crossing and the differences between them will become more and more accentuated, and with that the subspecies appear.
Over time, these subspecies may become so different from each other that reproduction between them becomes impossible.
When this happens, reproductive isolation occurs and, consequently, the emergence of new species. When speciation occurs due to geographic isolation, it is called allopatric speciation.