AP BIOLOGY

Detailed explanation-1: -Structures that have no apparent function and appear to be residual parts from a past ancestor are called vestigial structures. Examples of vestigial structures include the human appendix, the pelvic bone of a snake, and the wings of flightless birds.

Detailed explanation-2: -Vestigial structures are often called vestigial organs, although many of them are not actually organs. Such vestigial structures typically are degenerate, atrophied, or rudimentary, and tend to be much more variable than homologous non-vestigial parts.

Detailed explanation-3: -Vestigial structures serve little or no present purpose for an organism. The human tail, which is reduced to the tailbone during development, is one example. Vestigial structures can provide insights into an organism’s ancestry.

Detailed explanation-4: -A vestigial structure is a biological structure that has lost a major ancestral function and is usually drastically reduced in size. Well-known examples include the eyes of blind cave fishes and blind cave salamanders, and the diminutive wings of kiwis and emus.

Detailed explanation-5: -adjective. ves·ti·gial ve-ˈsti-jē-əl.-jəl. Synonyms of vestigial. of a body part or organ : remaining in a form that is small or imperfectly developed and not able to function : being or having the form of a vestige (see vestige sense 2)