Question

Speciation is the process by which new species are formed. Which of the following circumstances is most likely to lead to speciation? A. A population becomes separated by environmental factors into two groups that do not reproduce with one another. B. A population is unable to compete with other species and becomes extinct. C. A population reproduces beyond the carrying capacity of the ecosystem in which the population lives. D. A population begins to develop sexual dimorphism between the males and females of the species.

Answer 1

Answer is A. A population becomes separated by environmental factors into two groups that do not reproduce with one another.

When a population of a species become geographically separated then gene flow between them stops. Over a period of time, the population may become genetically different in response to the natural selection due to different environments. Selection and genetic drift will act differently on these two separated populations. This will results into two separate species. This type of speciation is called allopatric speciation.