AP BIOLOGY

Detailed explanation-1: -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.

Detailed explanation-2: -Allopatric speciation occurs in the absence of gene flow and sympatric speciation in the presence of gene flow. The two processes of speciation are very different and it is likely that the role of key innovations as a trigger of diversity differs as a consequence.

Detailed explanation-3: -Species are kept distinct from one another by prezygotic and postzygotic barriers. These barriers keep organisms of different species from mating to produce fertile offspring, acting before and after the formation of a zygote, respectively. These barriers maintain the reproductive isolation of species.

Detailed explanation-4: -Allopatric speciation is also known as geographical speciation. The difference in environmental factors causes the change in allopatric speciation. In sympatric speciation, the evolution of new species takes place from a single ancestral species.

Detailed explanation-5: -Parapatric speciation occurs when new species evolve in contiguous, yet spatially segregated habitats. Unlike allopatric speciation, the populations that are diverging during parapatric speciation maintain a zone of contact and do not cease the exchange of genes completely.