Question

Many organisms are darker on their dorsal surface and lighter on their ventral surface. They are difficult to see from both above and below because of this __________, which is called countershading.

a. Fixation

b. Adaptation

c. Pattern of resistance

d. Selection pressure

Answer 1

Countershading is an adaptation that provides animals camouflage, helping them avoid predators, and the increase in dark-colored moths after the Industrial Revolution represents an occurrence of directional selection.

Step-by-step explanation:

The phenomenon described, where organisms are darker on their dorsal surface and lighter on their ventral surface, is an adaptation known as countershading. This coloration makes animals less visible from both above and below, enhancing their ability to avoid predators and is a classic example of camouflage.

Using the provided information and applying the principles of natural selection, the change in moth coloration from light to dark that occurred after the Industrial Revolution is an example of directional selection. This is because the environmental conditions, darkened by industrial soot, favored dark-colored moths, which became more common in the population due to their better camouflage against predators on soot-darkened surfaces.