Exemplar Problems

Question:

Differentiate between prezygotic and postzygotic reproductive isolation mechanisms with examples.

Answer:

Prezygotic isolation prevents the formation of a fertilized egg (zygote) and includes mechanisms like temporal isolation (different mating times), behavioral isolation (different mating behaviors), and mechanical isolation (structural differences in reproductive organs). Postzygotic isolation occurs after fertilization, resulting in hybrid inviability (hybrids do not survive) or hybrid sterility (hybrids are sterile). An example of postzygotic isolation is the mule, a sterile hybrid of a horse and a donkey.