Humans are bipedal primates belonging to the species Homo sapiens (Latin: "wise man" or "knowing man") in Hominidae, the great ape family.Humans have a highly developed brain, capable of abstract reasoning, language, introspection, and problem solving. This mental capability, combined with an erect body carriage that frees the arms for manipulating objects, has allowed humans to make far greater use of tools than any other species. Mitochondrial DNA and fossil evidence indicates that modern humans originated in Africa about 200,000 years ago. Humans now inhabit every continent and low Earth orbit, with a total population of over 6.7 billion as of September 2009.