Question

Compare and contrast forms of pre-zygotic and post-zygotic reproductive isolation and provide examples of each.

A) Pre-zygotic isolation occurs before fertilization and includes mechanisms like geographic, temporal, and behavioral isolation. Post-zygotic isolation occurs after fertilization and includes mechanisms like hybrid inviability and hybrid sterility.

B) Pre-zygotic isolation occurs after fertilization and includes mechanisms like hybrid inviability and hybrid sterility. Post-zygotic isolation occurs before fertilization and includes mechanisms like geographic, temporal, and behavioral isolation.

C) Pre-zygotic and post-zygotic isolation both involve geographic isolation. Pre-zygotic isolation includes mechanisms like hybrid inviability, while post-zygotic isolation includes mechanisms like behavioral differences.

D) Pre-zygotic isolation occurs after fertilization and includes mechanisms like hybrid sterility. Post-zygotic isolation occurs before fertilization and includes mechanisms like temporal and behavioral differences.

Answer 1

Pre-zygotic barriers occur before fertilization and include geographic, temporal, and behavioral isolation. Post-zygotic barriers occur after fertilization and include hybrid inviability and hybrid sterility.

Step-by-step explanation:

Pre-zygotic barriers, occurring before fertilization, include mechanisms such as geographic, temporal, and behavioral isolation. For example, two frog species may inhabit the same area but have different breeding seasons, leading to temporal isolation.

Post-zygotic barriers, on the other hand, occur after fertilization and include mechanisms like hybrid inviability and hybrid sterility. Hybrid inviability refers to when hybrid organisms cannot develop normally in the womb and do not survive past the embryonic stages. Hybrid sterility is when hybrids are born sterile and unable to produce offspring of their own. For instance, mules, which are the offspring of a horse and a donkey, are usually infertile.