Spandrel (biology)

Stephen Jay Gould and Richard Lewontin brought the term into biology in their 1979 paper "The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme".

[2] The term was coined by paleontologist Stephen Jay Gould and population geneticist Richard Lewontin in their paper "The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme" (1979).

In the biological sense, a "spandrel" might result from a requirement inherent in the body plan of an organism, or as a byproduct of some other constraint on adaptive evolution.

Gould saw the term to be optimally suited for evolutionary biology for "the concept of a nonadaptive architectural by-product of definite and necessary form – a structure of particular size and shape that then becomes available for later and secondary utility".

Gould responded, "The term spandrel may be extended from its particular architectural use for two-dimensional byproducts to the generality of 'spaces left over', a definition that properly includes the San Marco pendentives.

[2][6] Critics such as H. Allen Orr argued that Lewontin and Gould's oversight in this regard illustrates their underestimation of the pervasiveness of adaptations found in nature.

This seems to imply that the design and secondary utilization of spandrels may feed back into the evolutionary process and thus determine major features of the entire structure.

The grounds Gould does accept to have validity in assigning or denying a structure the status of spandrel are historical order and comparative anatomy.

Evidence is obtained by comparing current examples of the structure in a cladistic context and by subsequently trying to determine a historical order from the distribution yielded by tabulation.

[13][14] Chomsky writes that the language faculty, and the property of discrete infinity or recursion that plays a central role in his theory of universal grammar (UG), may have evolved as a spandrel.

It shows no signs of design for attaining a goal such as long life, grandchildren, or accurate perception and prediction of the world", and "I suspect that music is auditory cheesecake, an exquisite confection crafted to tickle the sensitive spots of at least six of our mental faculties.