The common edible frog of Europe is a hybrid between two species, Rana lessonae and Rana ridibunda. The hybrids were first described in 1758 and have a wide distribution, from France across central Europe to Russia. Both male and female hybrids exist, but when the hybrids mate with other hybrids or with adults of either species, they are rarely successful in producing offspring. What can you infer from this information?
A) Postzygotic isolation exists between the two frog species.
B) Prezygotic isolation exists between the two frog species.
C) These two species are likely in the process of fusing back into one species.
D) The hybrids form a separate species under the biological species concept.

Question

Quizplus · Accepted Answer

The fact that the hybrids are rarely successful in producing offspring when they mate with other hybrids or with adults of either species suggests that there is postzygotic isolation between the two species, meaning that there are barriers preventing the formation of viable offspring after the formation of a zygote. This is a common form of reproductive isolation that occurs after fertilization.

The Common Edible Frog of Europe Is a Hybrid Between