Which term refers to unrelated organisms sharing a structure with similar function but different design?

The term that describes unrelated organisms sharing a structure with a similar function but different design is "analogous." This concept is rooted in evolutionary biology, where analogous structures arise not from a common evolutionary ancestor but from adapting to similar environmental challenges.

For example, the wings of bats and the wings of insects serve the same function of flying, but they have significantly different structures and origins. Bats are mammals with a wing structure that evolved from their forelimbs, while insect wings are extensions of the exoskeleton. This convergence in function, despite differing anatomical designs, characterizes analogous traits.

The concept contrasts with "homologous" structures, which are similar due to shared ancestry, even if they serve different functions or appear differently. Divergent refers to processes where species evolve different traits from a common ancestor, while convergent evolution refers more broadly to the process by which unrelated organisms independently evolve similar traits, but the term "analogous" specifically captures the essence of functional similarity despite different designs.