If you do not do this, subsequent windows displaying the answer will not be visible. Answer Key Explanations for selected questions 1. Directional selection is an example of artificial selection, stabilizing selection is not. Following stabilizing selection there is a change in the mean phenotype, but not in directional selection. Stabilizing selection always results in reduced variance.
Directional selection requires new mutations to arise.
Darwin's visit to the Galapagos Islands was of considerable significance in the development of his ideas on the mechanism of evolution. Patterns of geographical variation of related species on different islands. Gene flow between islands. Adaptive radiation of animals to particular habitats. High species diversity.