The Northern leopard frog (Rana pipiens) and Southern leopard frog (Rana utricularia) are morphologically similar, but their mating calls sound very different. Based on this, what is the best explanation for why these frogs are considered separate species?

A. They are too morphologically different to interbreed.

B. They have undergone behavioral isolation which prevents them from interbreeding.

C. They have undergone habitat isolation because one species is entirely terrestrial while the

other is entirely aquatic.

D. They do interbreed, but produce sterile hybrids

Answer:

B. They have undergone behavioral isolation which prevents them from interbreeding.

Explanation:

Behavioral isolation is a form prezygotic isolation that prevents related species, which have evolved different mating behavior or rituals, from interbreeding. Mating call sound is a type of ritual behavior. The Northern leopard frog (Rana pipiens) and Southern leopard frog (Rana utricularia) having evolved different mating calls sound, which is needed for attracting mates, would not be able to interbreed with each other, as the call sound of one would not be identified or attract the other for mating. This results in behavioral isolation.