A system of classifying things from the general to the specific is known as taxonomy. While taxonomic systems are used in various disciplines from business to computers, the most famous is the biological table for organisms found on earth. This system categorizes all living things based on kingdom, phylum or division, class, order, family, genus, species and variety. Thus a dog would be classified as animalia-chordata-mammalia-carnivora-canidae-canis-familiarus, according to Biology4Kids.
The scientist Carl Linnaeus designed the first taxonomic table, which was based on shared physical traits. Linnaeus began by dividing all of nature into three kingdoms: animal, vegetable and mineral. The taxonomic system has since been revised in accordance with the theory of evolution. Since the 1960s, a new system has been employed called cladistic taxonomy, which arranges organisms in an evolutionary tree. Organisms that share common ancestors are grouped in a clade. Humans are classified as Homo sapiens according to Linnaeus's binomial naming system, which is still used to identify every species. The hominids split into several branches, one of which was human, more than 5 million years ago. The first members of the big-brained Homo clade lived in Africa about 4 million years ago, according to University of California at Berkeley's Evolution 101. By 25,000 years ago, all other species of Homo had become extinct except Homo sapien.