Question

Explain the reason for the change in frequency of the left mouthed fish summarized in the graph

Answer 1

The scale-eating Perissodus microlepis, for example, has morphological dimorphism in the mouth-opening direction to right and left has been shown to be heritable.

Though environmental factors can influence the formation of this mouth laterality through development. But, several population models have demonstrated that this lateral dimorphism is maintained by negative frequency-dependent selection, resulting from interactions between predator and prey species.

An empirical study has suggested that disassortative mating between right-mouthed individuals and left-mouthed individuals stabilizes this intrapopulation dimorphism more strongly than only negative frequency-dependent selection acted.