Man or human commonly refers to the species Homo sapiens (Latin: "wise man" or "knowing man"),the only extant member of the Homo genus of bipedal primates in Hominidae, the great ape family. However, in some cases the term is used to refer to any member of the genus Homo.
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 hands for manipulating objects, has allowed humans to make far greater use of tools than any other species. Humans are a cosmopolitan species; widespread in every continent except Antarctica, with a total population of 6.8 billion as of November 2009.
Like most higher primates, humans are social by nature. However, humans are uniquely adept at utilizing systems of communication for self-expression, the exchange of ideas, and organization. Humans create complex social structures composed of many cooperating and competing groups, from family to nations.
Source: en.wikipedia.org/wiki/Human_being - 26.03.2010