Which type of speciation occurs when populations become geographically isolated?

Allopatric speciation occurs when populations of the same species become geographically isolated, leading to separate evolutionary paths. This geographic isolation can result from various barriers such as mountains, rivers, or distances that prevent individuals from mating. As these separated populations experience different environmental pressures and mutations over time, they can diverge genetically. Eventually, these changes might lead to reproductive isolation, meaning that even if the populations were to come back into contact, they could no longer interbreed successfully, thus forming new species.

Understanding allopatric speciation highlights the importance of geographic factors in the evolutionary process. In contrast, sympatric speciation happens without geographical barriers, parapatric speciation occurs along a gradient, and convergent evolution refers to unrelated species developing similar traits due to similar environmental pressures rather than from a common ancestor.