Biogeographic isolation means that a population is separated and there are two populations in two different areas. As normal mutations take place, but certain mutations will be seen as advantageous in the different areas. For. Example if an area had taller trees the organism may develop a gene to grow taller. This is then passed down to offspring. This process continues so that more gene differences are created within the species and the frequency of these alleles increased: leading to two different species developing-
That they are <span>caused by microorganisms.</span>
