What Is Allopatric Speciation?

Allopatric speciation occurs when a population is divided by a physical barrier—such as a mountain range, river, or vast distance—that prevents gene flow between the separated groups. Over time, these isolated populations experience different mutations, genetic drift, and natural selection pressures, leading to genetic divergence. Eventually, the populations become so different that even if the barrier is removed, they can no longer interbreed, thus becoming separate species.

Key Features of Allopatric Speciation

• Physical Isolation: A geographical barrier splits the population, preventing interbreeding.

• Independent Evolution: Each group evolves separately, accumulating unique genetic changes.

• Reproductive Isolation: Over generations, genetic differences become significant enough to prevent successful interbreeding, even if the barrier disappears.

Real-World Examples

• Darwin’s Finches: The classic example, where finch populations on different Galápagos Islands evolved into distinct species due to isolation and adaptation to different environments.

• Grand Canyon Squirrels: The formation of the Grand Canyon separated squirrel populations, leading to the evolution of two distinct species on opposite rims.

How Is Allopatric Speciation Different from Other Types?

Conclusion

The formation of two species from one parent population due to geographical isolation is called allopatric speciation. This process highlights the powerful role of physical barriers in driving evolutionary change and the emergence of biodiversity.

Correct answer:
(1) Allopatric speciation