Blue light is a portion of the visible spectrum that penetrates deep into bodies of water. Ultraviolet (UV) light, though, can penetrate even deeper. A gene within a population of marine fish that inhabits depths from 500 m to 1,000 m has an allele for a photopigment that is sensitive to UV light, and another allele for a photopigment that is sensitive to blue light. Which of the graphs in Figure 21.1 best depicts the predicted distribution of these alleles within a population if the fish that carry these alleles prefer to locate themselves where they can see best? Figure 21.1

Question

Blue light is a portion of the visible spectrum that penetrates deep into bodies of water. Ultraviolet (UV) light, though, can penetrate even deeper. A gene within a population of marine fish that inhabits depths from 500 m to 1,000 m has an allele for a photopigment that is sensitive to UV light, and another allele for a photopigment that is sensitive to blue light. Which of the graphs in Figure 21.1 best depicts the predicted distribution of these alleles within a population if the fish that carry these alleles prefer to locate themselves where they can see best?  Figure 21.1

Quizplus · Accepted Answer

Since UV light penetrates deeper into the water than blue light, fish with the allele for UV-sensitive photopigment would be better equipped to see in deeper waters than those with only the allele for blue-sensitive photopigment. Therefore, individuals with the UV-sensitive allele would have a higher fitness and be more likely to survive and reproduce in deeper waters. This would lead to an increase in the frequency of the UV-sensitive allele in the deeper parts of the population's habitat, as depicted in graph B.

Blue Light Is a Portion of the Visible Spectrum That