You are studying natural selection in a population of small marine invertebrates called isopods that live on pink corals. In this population, isopod body color is controlled by one gene with alternate alleles A and a. Isopods can be red (AA), pink (Aa), or white (aa); body size is controlled by another gene with alternate alleles B and b, and they can be large (BB or Bb) or small (bb). A new predator arrives on the reef that is extremely good at preying on isopods that are large and stand out against the corals on which they live (i.e., red or white individuals). Over time, which genetic individuals would you predict would become more abundant in the population with each subsequent generation?

Recall that this question calls our attention to the theory of evolution as postulated by Charles Darwin. Species that are well adapted to their environment are more likely to survive, reproduce and pass on these favourable characteristics to their offspring.

In this case, the coral reefs are pink and pink Isopod species with small bodies are likely to escape the predators. Hence the genetic combination Aa(pink body) and bb(small body) are more likely to survive and reproduce.