Imagine that a researcher is studying two different beaver populations. One of these populations consists of beavers with larger, rather unwieldy teeth that make eating difficult but that allow the beaver to take down very large trees. The other population consists of individuals with smaller teeth that make eating easier, but which are still capable of chewing through the wood of small trees. When a beaver dam fails, the two populations merge. Hybrids with medium-sized teeth are poorly adapted to the environment: Their teeth are too big to make eating easy, but they are not big enough to permit the felling of large trees. If a mutation arises that causes beavers with smaller-sized teeth to preferentially mate with individuals having the same size teeth, this would result in reinforcement of _____ isolation.
A)reproductive
B)species-size
C)analogous character
D)temporal species
E)ecological species

Question

Quizplus · Accepted Answer

Reinforcement of reproductive isolation occurs when natural selection favors individuals that mate with their own species, reducing the likelihood of producing unfit hybrids between two different populations or species. In this scenario, if beavers with smaller-sized teeth preferentially mate with individuals having the same size teeth, this would reinforce prezygotic reproductive isolation between the populations, as individuals with different tooth sizes will be less likely to mate and produce hybrids with poorly adapted traits.

Imagine That a Researcher Is Studying Two Different Beaver Populations