Question

Male frogs give calls that attract female frogs to approach and mate. Researchers examined mating calls of closely related tree frogs in South America. If reinforcement is occurring, what would you expect if you compare the calls of the two species in zones of sympatry versus zones of allopatry?

1) Calls would be about the same in both areas.
2) Calls would be more similar in areas of sympatry.
3) Calls would be more different in areas of sympatry.

Answer 1

If reinforcement is occurring, you would expect frog mating calls to be more different in zones of sympatry compared to zones of allopatry, due to the need to avoid hybridization and ensure reproductive success, reinforcing prezygotic barriers and contributing to speciation. The correct answer is option 1.

Step-by-step explanation:

When examining the mating calls of closely related tree frog species in South America, and considering the concept of reinforcement in zones of sympatry versus zones of allopatry, the expected finding in zones of sympatry would be that the calls of the two species are more different.

This differentiation is due to the process of reinforcement, where species develop more distinct traits to avoid hybridization and ensure reproductive success. In contrast, in zones of allopatry where the species do not coexist, the selective pressure to differentiate their calls is reduced, and therefore, their calls may be more similar.

Reinforcement strengthens prezygotic barriers to reproduction, making it less likely for individuals of different species to mate and produce hybrid offspring. The diverging mating calls in areas of sympatry serve as a form of prezygotic isolation. This prevents the mixing of genes between species and allows them to maintain separate identities. Such evolution of mating calls is an example of how behavioral isolation contributes to speciation.

Therefore, regarding the research on frog mating calls, the correct option is:

1. Calls would be more different in areas of sympatry.