Two species of tree frogs that live sympatrically in the northeastern United States differ in ploidy: Hyla chrysocelis is diploid, and Hyla versicolor is tetraploid. The frogs are identical in appearance, but their mating calls, which females use to find mates, differ. Which difference most likely evolved first?
A) polyploidy
B) difference in mating calls
C) A and B must have occurred at the same time.

Question

Quizplus · Accepted Answer

Polyploidy likely evolved first, leading to reproductive isolation. The difference in mating calls could then evolve as a mechanism for species recognition, reinforcing the separation initiated by the change in ploidy.

Two Species of Tree Frogs That Live Sympatrically in the Northeastern