What is a primary outcome of allopatric speciation?

In allopatric speciation, populations of a single species become geographically isolated from one another, often due to physical barriers such as mountains, rivers, or distance. This separation prevents gene flow between the populations, allowing them to evolve independently. Over time, as each isolated population adapts to its unique environment, genetic differences accumulate due to mutations, natural selection, and genetic drift.

The primary outcome of this process is the formation of new species. As genetic divergence increases, the populations may develop distinct traits and reproductive barriers, which ultimately lead to speciation. This process highlights the importance of geographic isolation in the diversification of life on Earth, as it creates opportunities for species to adapt to different ecological niches and conditions.

Other potential outcomes mentioned, such as increased genetic similarity, stabilization of populations, or uniform gene flow, do not reflect the fundamental changes that occur during allopatric speciation. Instead, allopatric speciation primarily results in the creation of new species through mechanisms driven by isolation and divergent evolution.