ABSTRACT
The early concepts of adaptation of an organism to its environment can be traced to the writings of Robert Malthus and Charles Darwin (Leake, 1964). These early concepts evolved through the work of Claude Bernard, Walter Cannon, Joseph Barcroft, and L. J. Henderson, to the current perspectives of C. Ladd Prosser ( 1964), Hans Selye (1952), and Peter Hochochka and George Somers (1973). For an extensive review, see Adaptation to the Environment, a volume of the Handbook of Physiology, edited by Bruce Dill and his associates (1964). Leake (1964) defined adaptation as an alteration in the structure or function of an organism that favors the survival of the organism in an altered environment. The adaptation of a total organism to environmental change occurs in molecules, cells, tissues, and organs (Barbashova, 1964; Hochochka and Somers, 1973). Furthermore, at each level, multiple mechanisms are available for the control of adaptive responses. Consequently, the adaptation of a total organism is highly complex (Adolph, 1956), and a hierarchical approach to an understanding of structure-function relationships is advisable (Fig. 1).
