Involves

Word

Exaptation

ek-sap-TAY-shun · noun

A feature recruited for a useful role different from the one for which it evolved, or from no prior adaptive role

Examples

  • Feathers used in flight illustrate exaptation when structures with earlier roles are recruited for aerodynamics.

  • Calling a feature an exaptation requires a historical claim, not merely noticing that it is useful.

Origin

The paleontologists Stephen Jay Gould and Elisabeth S. Vrba proposed the term in 1982. They wanted to distinguish features shaped by selection for their present role from features later recruited to that role. Their category also allowed useful recruitment of features that had not previously been adaptations.

How it connects

The word separates a feature's current job from its evolutionary origin.

This word appeared in Useful for a reason it did not begin with, the Involves connection for September 23, 2026, which asked: Does a feature's present function explain why it evolved?

Check yourself

Which claim most clearly describes exaptation?

A feature that evolved in one context is recruited for a different useful role. Exactly. Exaptation is a claim about how present use differs from historical origin.

What the sources establish

  • Gould and Vrba introduced exaptation in 1982 for useful features not originally selected for their present role.

Sources