The figures below illustrate two lineages with two variants: with and without a black spot.The arrows point to the descendants of the individual.In which situation can natural selection work?
A)In the diagram on the left; natural selection has eliminated the spotted variant.
B)In the diagram on the left; the number of offspring produced is independent of the mutation.
C)In the diagram on the right; variation is heritable.
D)In the diagram on the right; the mutation does not influence reproduction.

Question

The figures below illustrate two lineages with two variants: with and without a black spot.The arrows point to the descendants of the individual.In which situation can natural selection work? 
A)In the diagram on the left; natural selection has eliminated the spotted variant. 
B)In the diagram on the left; the number of offspring produced is independent of the mutation. 
C)In the diagram on the right; variation is heritable. 
D)In the diagram on the right; the mutation does not influence reproduction.

Quizplus · Accepted Answer

Natural selection can work only when there is heritable variation within a population, as seen in the diagram on the right. In this case, individuals can pass on traits to their offspring, and if those traits give some individuals a reproductive advantage, then those traits are more likely to be passed on to future generations. In contrast, the diagram on the left shows a situation where natural selection has already acted to eliminate one variant (the spotted variant). This does not necessarily mean that natural selection is still actively working in this population.

The Figures Below Illustrate Two Lineages with Two Variants: with and Without