Question

the peppered moth (white with small black speckles) is well camouflaged when resting on lichen - covered tree trunks. in the nineteenth century, domestic coal fires blackened urban trees. the solid black peppered moth came to outnumber the speckled form within the cities. more recently, the lichen is returning to the trees and the white moth is again more common. given this information, which of the following statements is true?

the moths mutate in order to survive.

the mutation leading to the black moth is an example of a neutral mutation.

the air pollution caused mutations in the genes that specify the moths coloring.

the allele that produces the white vs. black phenotype provides a selective advantage to the moth, depending on the environment.

Explanation:

• Option 1: Moths do not mutate "in order to survive." Mutations are random events, not directed by the organism's need for survival.
• Option 2: A neutral mutation has no effect on an organism's fitness. The black moth mutation was not neutral because it affected the moth's camouflage and thus its survival (fitness) in a polluted (black - tree) environment.
• Option 3: Air pollution did not cause mutations in the genes for moth coloring. Mutations are random. The pollution changed the selective pressure (the color of the trees), which favored the black - moth phenotype when trees were blackened.
• Option 4: When trees were lichen - covered (white), the white (speckled) moth had a selective advantage (better camouflage from predators). When trees were blackened by coal fires, the black moth had a selective advantage. Now that lichen is returning (trees are becoming lighter again), the white moth has a selective advantage. So, the allele for white vs. black phenotype provides a selective advantage depending on the environment.

Answer:

The allele that produces the white vs. black phenotype provides a selective advantage to the moth, depending on the environment.