What term describes similar body parts among different species that serve different functions?

The term that describes similar body parts among different species that serve different functions is "analogous structures." Analogous structures arise when different species independently evolve similar traits as a result of facing similar environmental challenges, rather than inheriting these traits from a common ancestor. For example, the wings of birds and insects serve the same function (flight) but are structurally different and evolved separately.

Homologous structures, in contrast, are features that are similar due to shared ancestry, even if they perform different functions. An example would be the forelimbs of humans and whales, which have different functions but share a similar underlying bone structure due to common ancestry.

Convergent evolution is the broader process that leads to the development of analogous structures. It refers to the independent evolution of similar traits in different species, typically as an adaptation to similar environments.

Vestigial structures are remnants of organs or features that served a function in the organism's ancestors but are no longer used in the same way or at all, such as the human appendix.