exaptive
exapted

Exaptive Translations between Biology and Architecture.

"The exaptive excellence of spandrels as a term and prototype" Proceedings of the National Academy of Sciences USA.

Proposed examples include the "masculinized genitalia in female hyenas, exaptive use of an umbilicus as a brooding chamber by snails, the shoulder hump of the giant Irish deer, and several key features of human mentality."

As a result, an exaptive explanation of consciousness has gained favor with some theorists that posit consciousness did not evolve as an adaptation but was an exaptation arising as a consequence of other developments such as increases in brain size or cortical rearrangement.

Gould responded that critics ignore that later selective value is a separate issue from origination as necessary consequences of structure; he summarised his use of the term 'spandrel' in 1997: "Evolutionary biology needs such an explicit term for features arising as byproducts, rather than adaptations, whatever their subsequent exaptive utility...."

But the biosphere is part of the physical universe, and the exapted wings of Gertrude the flying squirrel are manifestly observables, albeit classical observables.