exaptation

ex·ap·ta·tion | \ ˌeg-ˌzap-ˈtā-shən

Definition of exaptation

: a trait, feature, or structure of an organism or taxonomic group that takes on a function when none previously existed or that differs from its original function which had been derived by evolution As for exaptations, we need look no further than feathers. It is now argued that feathers were not originally evolved for flight, but emerged in the reptilian ancestors of today's birds, where they served for temperature regulation.— Steven Rose also : the condition or circumstance of possessing one or more such traits, features, or structures In fact, it's hard to say just how much of the brain's power is a result of exaptation rather than adaptation. — Tom Siegfried

Note: The word exaptation was proposed by Stephen Jay Gould and Elizabeth Vrba in the 1980s as an alternative to preadaptation, which was felt to imply that such traits, features, or structures were destined for a future function. While exaptation has been widely adopted, preadaptation continues to be acceptable in current usage with both terms showing comparable frequency of usage.

Examples of exaptation in a Sentence

Recent Examples on the Web In 1982, Stephen Jay Gould and Elisabeth Vrba gave a name to this phenomenon: exaptation. — Quanta Magazine, "Evolution as Opportunist," 4 Sep. 2013 Feathers are a marvelous example of exaptation, or the process of acquiring functions for which they were not originally adapted. — Kate Morgan, CNN, "The brain benefits of your child's dinosaur obsession," 12 Dec. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'exaptation.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.