Question

5) You are in the field studying two species of Tanager, the Western Tanager and the Summer Tanager. You notice that the male birds are brightly colored and do an elaborate dance to attract females. The males do not appear to be picky; they court females of both species. The females, however, only respond to the males of their own species; they never mate with males of the other species. You then catch 10 males and 10 females of each species and bring them back to the lab. In the lab, after some persuasion (Barry White and a nice bottle of wine), you successfully mate male Western Tanagers to female Summer Tanagers. When the eggs hatch, all of the offspring are male, no female chicks came of the hybridization. What type of prezygotic barrier to gene flow is this? What type of postzygotic barrier?

Answer 1

Answer:

The prezygotic barrier that is, the barrier to the flow of gene prior to the formation of the zygote or prior to the process of fertilization in the given case is behavioral. As it is the behavior of the female birds, who want to mate only with the males of their own species.  

While the post-zygotic barrier, that is, barrier after fertilization in the given case would have been the hybrid inviability. As all the hybrids born were males, which signifies that the female zygotes are inviable and did not survive post-fertilization.