Spandrel

'''Spandrel''' is a term used in evolutionary biology describing a phenotypic characteristic that is considered to have developed during evolution as a [[Side-effect|side-effect]] of an [[Adaptation|adaptation]], rather than arising from [[Natural Selection|natural selection]]. The term was coined by the Harvard paleontologist Stephen Jay Gould and population geneticist Richard Lewontin in their influential paper "The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme" (1979). They drew the analogy with spandrels in Renaissance architecture, which are curved areas of masonry above an arch, which they considered to be necessary side consequence arising from decisions concerned with the shape of the arch and the circumferential ring of the base of the dome, rather than being deliberately designed for direct utility in themselves. Properties that they singled out were the necessary number of four and their specific three-dimensional shape.