Maintenance of the adequate function is a general principle of survival of organisms.
A general theory which describes the existence of live organisms is introduced; this theory is the Principle of Adequate Function and it describes all the situations in which live organisms may exist, whether healthy or sick at both physiological and pathological conditions. In biology, so far, the existence of living organisms under physiological conditions is described by homeostasis, and under pathological conditions specific immunity is used. As it is shown below, adaptation and non-specific resistance provide a much broader basis of how living organisms exist under both physiological and pathological conditions. This general theory does not interfere with the notions of homeostasis, adaptation, and specific immunity but includes them as particular cases. It is proposed that the principle of adequate function supplements the description of life processes by the evolutionary principle; it describes the laws of existence and function of a particular individual.
D000220:Adaptation, Biological; D000222:Adaptation, Physiological; D000818:Animals; D000917:Antibody Formation; D001806:Blood Urea Nitrogen; D001833:Body Temperature Regulation; D004734:Energy Metabolism; D006706:Homeostasis; D006801:Humans; D007110:Immunity, Active; D014882:Water-Electrolyte Balance