what is a vestigial structure

A vestigial structure is a feature that a species inherited from an ancestor but that is now less elaborate and functional than in the ancestor/18%3A_Evolution_and_the_Origin_of_Species/18.05%3A_Evidence_of_Evolution/18.5H%3A_Vestigial_Structures). These structures can be various cells, tissues, and organs in a body which no longer serve a function. Vestigial structures are formed when a lineage experiences a different set of selective circumstances than its ancestors, and selection to maintain the elaboration and function of the feature ends or is greatly reduced. Although structures commonly regarded as "vestigial" may have lost some or all of the functional roles that they had played in ancestral organisms, such structures may retain lesser functions or may have become adapted to new roles in extant populations. Vestigial structures are often homologous to structures that are functioning normally in other species, and therefore, they provide strong evidence of common ancestry and can help us trace the evolutionary origin of the species with the vestigial structures. Examples of vestigial structures in humans include the appendix, the coccyx, and wisdom teeth.