The evolutionary significance of reproductive isolation lies in its role in the formation of new species, or speciation. Reproductive isolation occurs when populations can no longer interbreed due to genetic, behavioral, temporal, or ecological barriers. This separation leads to the divergence of gene pools, allowing populations to evolve independently. Over time, this can result in the emergence of new species with distinct adaptations, thereby contributing to biodiversity. Understanding reproductive isolation provides insights into evolutionary processes and mechanisms driving natural selection.