How can reproductive isolation contribute to speciation?

Reproductive isolation is a crucial factor in the process of speciation because it prevents different species from interbreeding. This isolation can occur through various mechanisms such as temporal, behavioral, mechanical, and geographical barriers. When interbreeding is prevented, gene flow between populations ceases, which allows the separated groups to evolve independently. Over time, these populations can accumulate genetic differences due to natural selection, genetic drift, and mutation, leading to the emergence of new species.

In contrast, if species were allowed to interbreed, gene flow would homogenize their genetic differences, undermining the divergence necessary for speciation. Therefore, reproductive isolation plays a key role in enabling the evolutionary processes that ultimately lead to the formation of distinct species.