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 homologous to fully functioning structures inherited by related lineages. Thus, they provide strong evidence of common ancestry and can help us trace the evolutionary origin of the species with the vestigial structures.

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: -Charles Darwin listed a number of putative human vestigial features, which he termed rudimentary, in The Descent of Man (1871). These included the muscles of the ear; wisdom teeth; the appendix; the tail bone; body hair; and the semilunar fold in the corner of the eye.