AP BIOLOGY

Detailed explanation-1: -The case of the peppered moth (Biston betularia) is a classic example of evolution through directional selection (selection favoring extreme phenotypes). Prior to the industrial revolution in England (pre-1740), the peppered moth was found almost entirely in its light form (light body colored with black spots).

Detailed explanation-2: -The evolution of the peppered moth is an evolutionary instance of directional colour change in the moth population as a consequence of air pollution during the Industrial Revolution. The frequency of dark-coloured moths increased at that time, an example of industrial melanism.

Detailed explanation-3: -An example of directional selection is the increase in darker forms of the peppered moth (Biston betularia) that occurred in industrial areas, where the moths with darker wing coloration are better camouflaged than those with lighter wings against polluted tree trunks (see industrial melanism).

Detailed explanation-4: -In the last 50 years, most industrial countries have significantly reduced their pollution. As predicted by the theory, the number of dark moths are dropping as the forests become cleaner. Natural selection in peppered moths has been extensively studied.