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Homo sapiens (Latin: wise human) is a biological species, a mammal and the only surviving species of the genus Homo. The species is commonly referred to as "humankind", "humanity", "humans", "people". (Also sometimes called "man" or "mankind", but that usage is discouraged these days on the grounds of gender neutrality.) Misplaced Pages is contributed to by members of this species.

Homo sapiens Compared to Other Species

Most human beings consider themselves to be the "dominant" species, and most advanced in intelligence and ability to manage their environment. This belief is especially strong in Western culture, and is based in part in the Biblical creation-story, in which Adam is explicitly given dominion over the Earth and all of its creatures.

Many natural scientists, especially those who work within Darwin's theory of evolution of species through natural selection reject this view. Biologists and scientists in general do not consider the term "dominant" to be a useful term, as it is usually intended to mean superiority, and superiority can be measured in many ways. They use quite a different set of terminology to classify homo sapiens and other species in terms of their relation to other species.

From a scientific standpoint, homo sapiens is among the most generalized species on Earth and inhabits nearly all landmasses (a "generalized" trait is one that is suited to many different functions; an organism that is highly generalized can survive in a greater variety of environments). Smaller and simpler animals such as bacteria and insects greatly surpass humans in population size and diversity of species. They are also able to survive unaided in many environments where humans rely on external tools such as clothing and manufactured shelter.

The use of tools and the ability to alter their environment (building shelter, weaving fabrics for clothing, etc.) is another characteristic which distinguishes humans from other animals. While some other animals are also capable of using tools, such as chimpanzees which are known to "fish" for insects using blades of grass, no other animal uses tools to the same degree or with the same flexibility as homo sapiens.

Another distinguishing characteristic of homo sapiens is their use of language. Other animals often have methods of communication, but the degree to which humans have created languages and writing are unique. Spoken language provides humans the ability to communicate very well and to convey complex concepts. Written language, which developed later, added the ability to record knowledge and events for use by later generations.

Some of the closest living evolutionary relatives to humans are the hominids chimpanzees, orangutans and gorillas.

The Evolution of Homo sapeins

The evolution of genus Homo spans over 2 million years and the fossil record is far from complete; as paleoanthropologists discover new evidence, models of human evolution change. Anthropologists generally recognize three species of hominenes: Homo habilus, Homo erectus, and Homo sapiens.

H. habilus, the first species of genus Homo, evolved in South and East Africa in the late Pliocene or early Pleistocene (2 - 2.5 million years b.p.) when it diverged from the Australopithecines. Both genera were bi-pedal. H. habilus had smaller molars and larger brains than the Australopithecines, and made tools from stone and perhaps animal bones.

In the Early Pleistocene, from 1.5 to 1 million years b.p. hominines in Africa, Asia, and Europe, evolved larger brains and more elaborate stone tools; these differences and others are sufficient for anthropologists to classify them as a new species, Homo erectus. The direct evidence suggests that there was a migration out of Africa of H. erectus, then a further speciation of H. sapiens from H. erectus in Africa and a subsequent migration out of Africa which replaced dispersed H. erectus. There is little evidence that this speciation occurred elsewhere, even though some fossil evidence for H. erectus has been found in China. However, the current evidence doesn't preclude multiregional speciation, either. This is a hotly debated area in paleoanthropology.

Between 400, 000 years b.p. and the second interglacial period in the Middle Pleistocene, around 250,000 years b.p., the trend in cranial expansion and the elaboration of stone tool technologies developed, providing evidence for a transition from H. erectus to H. sapiens. Anthropologists currently identify two subspecies of H. sapiens: neanderthaloids, and modern humans (originally identified as Cro-Magnon). Current evidence suggests that the two subspecies diverged during the fourth glacial period around 40,000 years b.p., after which neanderthaloids died out.

Important fossils:

• Petralona, Greece, about 300k years old. Contained many features of H. erectus.

• Arago, France, about 300k years old. Oldest skull clearly of H. sapiens origin.

The origins of humanity is a subject of great political and religious controversy in the United States and certain other countries. See: creationism.

See also: Homo neanderthalensis.

Location in the evolutionary tree:

• Kingdom Animalia

• Phylum Chordata

• Class Mammalia

• Order Primates

• Family Hominidae (humans, great apes and their extinct relatives)

External links:

• A Look at Modern Human Origins

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