Contrast
- Analogous features are structures similar in different organisms and serve the same function but have evolved independently. Bat and bird wings are two examples.
- Homologous features are structures similar in different organisms and have a common evolutionary origin. Human forelimbs, whales, and bats are all examples.
- Vestigial features are structures in an organism that have lost their function but remain present due to their evolutionary history. Consider the human appendix.
Side note
According to recent research, the appendix is a repository of beneficial gut bacteria that can repopulate the gut after an illness that flushes out the bacteria, such as diarrhea. This new understanding of the appendix suggests that it is not a completely vestigial structure and may serve a different purpose than its ancestral function.