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Definition

noun

(1) An organismic or systemic response of an individual to a specific external stimulus in order to maintain homeostasis.

(2) A metabolic or physiologic adjustment within the cell, or tissues, of an organism in response to an environmental stimulus resulting in the improved ability of that organism to cope with its changing environment.

Supplement

Unlike evolutionary adaptation which involves transgenerational adjustment, physiological adaptation is generally narrow in scope and involves response of an individual to a particular, usually narrow, range of stimuli. Examples of physiological adaptation are tanning of skin when exposed to sun over long periods, the formation of callouses on hands in response to repeated contact or pressure, and the ability of certain organisms to absorb nutrients under low oxygen tensions.