Human Evolution

Human Evolution

Human Evolution, the biological and cultural development of the species Homo

sapiens, or human beings. A large number of fossil bones and teeth have been

found at various places throughout Africa, Europe, and Asia. Tools of stone,

bone, and wood, as well as fire hearths, campsites, and burials, also have been

discovered and excavated. As a result of these discoveries, a picture of human

evolution during the past 4 to 5 million years has emerged.

Human Physical Traits Humans are classified in the mammalian order Primates;

within this order, humans, along with our extinct close ancestors, and our

nearest living relatives, the African apes, are sometimes placed together in the

family Hominidae because of genetic similarities, although classification

systems more commonly still place great apes in a separate family, Pongidae. If

the single grouping, Hominidae, is used, the separate human line in the hominid

family is distinguished by being placed in a subfamily, Homininae, whose members

are then called hominines—the practice that is followed in this article. An

examination of the fossil record of the hominines reveals several biological and

behavioral trends characteristic of the hominine subfamily.

Bipedalism Two-legged walking, or bipedalism, seems to be one of the earliest of

the major hominine characteristics to have evolved. This form of locomotion led

to a number of skeletal modifications in the lower spinal column, pelvis, and

legs. Because these changes can be documented in fossil bone, bipedalism usually

is seen as the defining trait of the subfamily Homininae.

Brain Size and Body Size Much of the human ability to make and use tools and

other objects stems from the large size and complexity of the human brain. Most

modern humans have a braincase volume of between 1300 and 1500 cc (between 79.3

and 91.5 cu in). In the course of human evolution the size of the brain has more

than tripled. The increase in brain size may be related to changes in hominine

behavior. Over time, stone tools and other artifacts became increasingly

numerous and sophisticated. Archaeological sites, too, show more intense

occupation in later phases of human biological history. In addition, the

geographic areas occupied by our ancestors expanded during the course of human

evolution. Earliest known from eastern and southern Afri...

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...racterized the earlier stages of human history, some innovations did take

place. In addition to the first appearance of the great cave art of France and

Spain See CAVE DWELLERS, some anthropologists have argued that it was during

this time that human language originated, a development that would have had

profound implications for all aspects of human activity. About 10,000 years ago,

one of the most important events in human history took place—plants were

domesticated, and soon after, animals as well. This agricultural revolution set

the stage for the events in human history that eventually led to civilization.

Modern understanding of human evolution rests on known fossils, but the picture

is far from complete. Only future fossil discoveries will enable scientists to

fill many of the blanks in the present picture of human evolution. Employing

sophisticated technological devices as well as the accumulated knowledge of the

patterns of geological deposition, anthropologists are now able to pinpoint the

most promising locations for fossil hunting more accurately. In the years ahead

this will result in an enormous increase in the understanding of human

biological history.