How does allopatric speciation work?

Allopatric speciation occurs when the population of a species becomes divided and the two (or more) groups are isolated from one another. Different factors in the environment of each group will affect the progression of their gene pools, these factors are referred to as selection pressures.Random genetic mutation occurs in the populations of all species however the introduction of different selection pressures to each group will provide advantages to individuals with certain mutations allowing them to survive and reproduce more than others passing their successful genes on to their offspring.With time, the two populations will gradually become more genetically different from one another until they reach the point at which they could no longer interbreed successfully. At this point speciation has occurred.