How do new and different species develop? How do existing species change over time? The answer to these questions is found through the process of . According to Monroe W. Strickberger, a professor at the University of Missouri in St. Louis, is defined as, "Genetic changes in populations of organisms through time that lead to differences among them" (519). has many mechanisms through which these genetic changes occur. One of the most important of these mechanisms is natural selection. Before the theory of natural selection was proposed, ....