Molecular Evidence
All living things are fundamentally alike. At the cellular and molecular level living things are remarkably similar to each other. These fundamental similarities are most easily explained by evolutionary theory: life shares a common ancestor. Different species share genetic homologies as well as anatomical ones. Roundworms, for example, share 25% of their genes with humans.
Selective Breeding
Selective breeding (also called artificial selection) is the process by which humans breed other animals and plants for particular traits. Typically, strains that are selectively bred are domesticated, and the breeding is normally done by a professional breeder. Bred animals are known as breeds, while bred plants are known as varieties, cultigens, or cultivars. The offspring of two purebreed animals but of different breeds is called a crossbreed, and crossbred plants are called hybrids.