The process by which evolution leads to the development of new species is known as speciation. Speciation occurs when populations of a single species become isolated, either geographically or genetically, causing them to evolve independently. Over time, these populations can accumulate genetic differences that result in reproductive barriers, preventing them from interbreeding. This can be driven by mechanisms such as natural selection, genetic drift, and mutation, ultimately leading to the emergence of distinct species adapted to their unique environments.