On the Bahamian island of Andros, mosquitofish populations live in various, now-isolated, freshwater ponds that were once united. Currently, some predator-rich ponds have mosquitofish that can swim in short, fast bursts; other predator-poor ponds have mosquitofish that can swim continuously for a long time. When placed together in the same body of water, the two kinds of female mosquitofish exhibit exclusive breeding preferences.
If one builds a canal linking a predator-rich pond to a predator-poor pond, then what type of selection should subsequently be most expected among the mosquitofish in the original predator-rich pond, and what type should be most expected among the mosquitofish in the formerly predator-poor pond?

Question

Quizplus · Accepted Answer

After the canal is built and the predator-poor and predator-rich ponds are connected, it is expected that the mosquitofish in the predator-rich pond will experience less-intense directional selection towards swimming ability, as they now have access to the gene pool of the predator-poor pond. In contrast, the mosquitofish in the formerly predator-poor pond are expected to experience more-intense directional selection towards swimming ability, as they are now exposed to predation pressure from the predator-rich pond. Overall, this would result in a less-intense directional selection of the predator-rich pond and a more-intense directional selection of the formerly predator-poor pond.

On the Bahamian Island of Andros, Mosquitofish Populations Live in Various