Question

You observe two groups of freshwater fish that spawn at the same time of the year and in the same pond. After females lay their eggs on the pond bottom, males of both species attempt to fertilize them. After some investigation you realize that sperm from both species fertilize the eggs, but embryonic development stops shortly after fertilization when the eggs are fertilized by one species of males, but not by the other. This is an example of ______- zygotic reproductive isolation between the two species.

Answer 1

Answer:

The given blank can be filled with post.

Explanation:

A mechanism, which prevents the species from mating with others is termed as reproductive isolation. It is further differentiated into pre-zygotic and post-zygotic isolation. The phenomenon of prezygotic isolation inhibits the eggs to get fertilize, while the postzygotic isolation inhibits the generation of fertile offspring.  

The mechanisms of prezygotic isolation comprise mating seasons, habitat isolation, gamete isolation, mechanical isolation, and behavioral isolation. On the other hand, postzygotic mechanisms comprise hybrid sterility, hybrid inviability, and hybrid breakdown. Thus, the given case is an example of post-zygotic isolation.