Paraphyly facts for kids

Paraphyly is a term in cladistics. It means a group which does not include all its descendents. So Sauropsida without birds is paraphyletic, since birds are definitely descended from archosaurs, probably small theropod dinosaurs (origin of birds).

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Paraphyly is corrected to monophyly when the missing group(s) are included. So if birds are included in Sauropsida, the larger group is then monophyletic. Traditional classification is often paraphyletic.

Related pages

• Polyphyly

Images for kids

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  In this phylogenetic tree, the green group is paraphyletic; it is composed of a common ancestor (the lowest green vertical stem) and its descendents, but it excludes the blue group (a monophyletic group) which diverged from the green group.

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  Reptilia (green field) is a paraphyletic group comprising all amniotes (Amniota) except for two subgroups: Mammalia (mammals) and Aves (birds); therefore, Reptilia is not a clade. In contrast, Amniota itself is a clade, which is a monophyletic group.