These population segments are reffered to as peripheral isolates. Dr. Gould's work is very important because he was the first person in the twentieth century to do significant research Darwin's theory of natural selection. He essentially cleaned up the edges of Darwin's theory. Ever Since Darwin , he bases his theory on Charles Darwin's Theory of Natural Selection. Organisms vary, and the variations are inherited by their offspring.
Organisms produce more offspring than can possibly survive.
On average, offspring that vary most strongly in directions favored by the environment will survive and propagate. Variation will therefore accumulate in populations by natural selection. Gould adds two more dimensions to Darwin's Theory of Natural Selection. First, variation must be random, or at least not preferentially inclined toward adaptation. For if variation comes pre- packaged in the right direction then selection plays no creative role, but merely eliminates the unlucky individuals who do not vary in the appropriate way.