Chapter Two—
2. Man: A Living Being
Needs and Capacities
From the simplest unicellular animal to man, the most complex of organisms, all living entities possess a
characteristic structure, the component parts of which function in such a way as to preserve the integrity of that
structure, thereby maintaining the life of the organism.
An organism has been described, correctly, as being not an aggregate, but an integrate. When an organism ceases to
perform the actions necessary to maintain its structural integrity, it dies. Death is disintegration. When the life of
the organism ends, what remains is merely a collection of decomposing chemical compounds.
For all living entities, action is a necessity of survival. Life is motion, a process of self-sustaining action that an
organism must carry on constantly in order to remain in existence. This principle is equally evident in the simple
energy-conversions of the plant and in the long-range, complex activities of man. Biologically, inactivity is death.
The action that an organism must perform is both internal, as in the process of metabolism, and external, as in the
process of seeking food.
The pattern of all self-preserving action is, in essence, as follows: an organism maintains itself by taking materials
which exist in its environment, transforming or rearranging them, and thereby converting them into the means of its
own survival.
Consider the processes of nutrition, respiration, and synthesis, which, together with their related functions,
comprise metabolism.