Artificial selection: domestic animals and plants: to increase the frequency of desirable traits in their stocks, plant and animal breeders employ artificial selection (example of darwin and his pigeon"s on. Evolution by natural selection: darwin realized that a process like artificial selection occurs in nature, his theory of evolution by natural selection suggests that descent with modification is the logical outcome of four postulates: Individuals within populations are variable: the variations among individuals are, at least in part, passed from parents to offspring. In every generation, some individuals are most successful at surviving and reproducing than others: the survival and reproduction of individuals are not random; instead they are tied to the variation among individuals. 3. 3 the evolution of flower color in an experimental snapdragon population. K. n jones and j. reithel (2001) did an experiment using 48 snapdragons to see if. Darwin"s four postulates are true: postulate 1: there is variation among individuals, the snapdragons varied in flower color.