takes in substances, grows, moves, is irritable, and reproduces. Often, it is difficult to
distinguish between living and nonliving materials. But in the ultimate analysis only
living materials perform all of these functions.
1-7. VARIATIONS AMONG HUMAN ORGANISMS
The human organism is known scientifically as Homo sapiens, meaning the
intelligent human being. There is a more or less common form for human beings. This
common form includes one head, two upper members, two lower members, etc., but
there are no two individuals exactly alike in detail. (This even includes identical twins.
One tends to be left-oriented and the other right-oriented.) As a result, there is a
tremendous variation among humans which has been further complicated by selection
and propagation of specific traits by humans themselves.
Given the variations among human organisms, various methods of categorization
have been established to achieve some common order. The method we will use is
referred to as somatotyping. See Figure 1-1.
Figure 1-1. Human somatotypes.