AP BIOLOGY

Detailed explanation-1: -Hence, hybrid sterility is a form of postzygotic isolation mechanism. The other options are wrong because of the following reasons: a) Mechanical isolation-interbreeding between the species is prevented due to anatomical differences.

Detailed explanation-2: -Which of the following describes a postzygotic isolating mechanism? Offspring produced are infertile, as they have a random number of chromosomes.

Detailed explanation-3: -What term describes the failure of one species’ sperm to fertilize the egg of a different species? Gametic incompatibility. The eastern meadowlark and the western meadowlark are two bird species that look very similar to each other.

Detailed explanation-4: -Allopatric speciation (1) occurs when a species separates into two separate groups which are isolated from one another. A physical barrier, such as a mountain range or a waterway, makes it impossible for them to breed with one another.