Vestigiality

In humans the vermiform appendix is a vestigial structure; it has lost much of its ancestral function.

The Darwin-tubercle (left) is a vestigial form of the ear tip (right) in the mammalian ancestors of humans - here shown in a Barbary Ape.

Vestigial hindlegs (spurs) in a Boa constrictor

The blind mole rat (Spalax typhlus) has tiny eyes completely covered by a layer of skin.

Vestigiality refers to genetically determined structures or attributes that have apparently lost most or all of their ancestral function in a given species, but have been retained during the process of evolution. Assessment of the vestigiality must generally rely on comparison with homologous features in related species. The emergence of vestigiality occurs by normal evolutionary processes, typically by loss of function of a feature that is no longer subject to positive selection pressures when it loses its value in a changing environment. The feature may be selected against more urgently when its function becomes definitively harmful. Typical examples of both types occur in the loss of flying capability in island-dwelling species.

单词	Vestigial Organs
释义	Vestigial Organs 原声例句生活大爆炸(视频版) 第4季 I am betrayed by my appendix, a vestigial organ. 我被自己的阑尾所背叛就一退化的器官。英语百科 Vestigiality Vestigiality refers to genetically determined structures or attributes that have apparently lost most or all of their ancestral function in a given species, but have been retained during the process of evolution. Assessment of the vestigiality must generally rely on comparison with homologous features in related species. The emergence of vestigiality occurs by normal evolutionary processes, typically by loss of function of a feature that is no longer subject to positive selection pressures when it loses its value in a changing environment. The feature may be selected against more urgently when its function becomes definitively harmful. Typical examples of both types occur in the loss of flying capability in island-dwelling species.
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Vestigial Organs

Vestigiality