vestigial structure

biology

Also known as: vestigial organ

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Last updated

July 14, 2026

Quick Summary

In biology, a vestigial structure is a body part or organ that remains in a small or imperfectly developed form, rendering it unable to function. These structures are remnants of evolutionary history, serving as "footprints" from ancestral species.12

Examples in humans include:
* Wisdom teeth: Reduced in size due to dietary changes and smaller jaws.2
* Tailbone (coccyx): A remnant of a tail that is present in early human embryos but fuses into the coccyx in adults.32
* Appendix: A functionless vestige of a larger organ in herbivores used for digesting cellulose.3
* Palmaris longus muscle: A muscle in the forearm that is absent in about 10% of humans and has no impact on grip strength.2

These imperfectly developed structures support the theory of evolution, as they are understandable as a result of evolutionary changes rather than design.3

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evolution
Embryonic development and vestiges
…vermiform appendix is a functionless vestige of a fully developed organ present in other mammals, such as the rabbit and other herbivores, where a large cecum and appendix store vegetable cellulose to enable its digestion with the help of bacteria. Vestiges are instances of imperfections—like the imperfections seen in anatomical…
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…vermiform appendix is a functionless vestige of a fully developed organ present in other mammals, such as the rabbit and other herbivores, where a large cecum and appendix store vegetable cellulose to enable its digestion with the help of bacteria. Vestiges are instances of imperfections—like the imperfections seen in anatomical…
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morphology
Anatomy
…many plants and animals contain organs or parts of organs that are useless, degenerate, undersized, or lacking some essential part when compared with homologous structures in related organisms. The human body, for instance, has more than 100 such organs—e.g., the appendix, the fused tail vertebrae (coccyx), the wisdom teeth, the…
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…many plants and animals contain organs or parts of organs that are useless, degenerate, undersized, or lacking some essential part when compared with homologous structures in related organisms. The human body, for instance, has more than 100 such organs—e.g., the appendix, the fused tail vertebrae (coccyx), the wisdom teeth, the…
Read More