What is the term for related organisms that share a similar structure with a different function?

The term that describes related organisms sharing a similar structure although serving different functions is "homologous." Homologous structures indicate a common evolutionary ancestor, as they arise from the same embryonic tissues and exhibit similarities due to shared ancestry.

For example, the forelimbs of humans, whales, and bats have similar bone structures (such as humerus, radius, and ulna) but serve different purposes: manipulation, swimming, and flying, respectively. This structural similarity stems from their descent from a common ancestor, despite their different functional applications.

In contrast, analogous structures arise independently in different species and serve similar functions but do not share a common evolutionary origin. This occurs through a process known as convergent evolution. Divergent evolution refers to the process in which related species evolve different traits, typically after diverging from a common ancestor.