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 they mate among themselves, they are rarely successful in producing offspring. What can you infer from this information?
A) These two species are likely in the process of fusing back into one species.
B) The hybrids form a separate species under the biological species concept.
C) Postzygotic isolation exists between the two frog species.
D) Prezygotic isolation exists between the two frog species.

Question

Quizplus · Accepted Answer

The inability of the hybrids to produce viable offspring when mating among themselves suggests that postzygotic isolation exists between the two frog species. This means that any hybrids produced between Rana lessonae and Rana ridibunda are not fully fertile, as shown by the low success rate of their mating. Therefore, they cannot merge back into a single species, nor can they be considered a separate species, as they are not reproductively isolated from their parent species.

The Common Edible Frog of Europe Is a Hybrid Between