Question

Why does geographic isolation cause speciation?

Answer 1

Geographical isolation can cause speciation if the separate geographical areas are different.

Explanation:

When a population of organisms are geographically isolated and these areas have different environmental conditions, the two populations can begin to diverge due to the different selection pressures. The different locations will have different favoured characteristics for the separate populations.

As the two populations cannot interact with each other due to the physical limitations, after long periods of time speciation can occur where the two populations become so different they can no longer interbreed. The two species diverged from the same population and evolution would have occurred for these populations by gradualism.