exaptive
/ɛɡˈzæptɪv/
adjective
- Relating to a feature that evolved for one purpose but later became useful for a different function.
- Some scientists argue that language may have an exaptive origin, building on earlier communication systems.
- Feathers are an exaptive trait that originally helped dinosaurs stay warm before they were used for flight.
- The exaptive nature of the human thumb allowed it to become a tool for gripping as well as climbing.