Ohio Assessment for Educators (OAE) Integrated Science (024) Practice Exam

Which type of speciation occurs in populations that are geographically isolated?

1. Sympatric speciation

2. Allopatric speciation

3. Adaptive radiation

4. Temporal isolation

The correct answer is: Allopatric speciation

Allopatric speciation is the process by which new species arise when populations become geographically isolated from one another. This isolation prevents gene flow between the populations, allowing them to evolve independently through natural selection, genetic drift, and mutation. Over time, these evolutionary changes can lead to the development of distinct characteristics that define new species. In the context of allopatric speciation, geographic barriers such as mountains, rivers, or distance can significantly affect the populations involved. As they adapt to their unique environments and conditions, they accumulate genetic differences, making it increasingly likely that they will become separate species. The other types of speciation, such as sympatric speciation, occur without geographic barriers, meaning populations remain in close proximity but may diverge due to behavioral, temporal, or ecological factors. Adaptive radiation describes the rapid evolution of diversely adapted species from a common ancestor, often following the colonization of new habitats, not strictly based on geographic isolation. Temporal isolation refers to populations that breed at different times, which can lead to speciation but does not involve geographical separation.