Editing Polyphyly (section)

{{short description|Property of a group not united by common ancestry}}
[[File:Clade-grade II.svg|thumb|300px|In this [[phylogenetic tree]], the blue and red groups (which are both ''monophyletic'') do not share an immediate common ancestor. If they are grouped together because they share characteristics which appear to be similar, then their combination forms a ''polyphyletic group''.]]
[[File:Monophyly, paraphyly, polyphyly.svg|thumb|300px|[[Cladogram]] of the [[primate]]s, showing a [[monophyly]] (the simians, in yellow), a [[paraphyly]] (the prosimians, in cyan, including the red patch), and a polyphyly (the night-active primates, the [[loris]]es and the [[tarsier]]s, in red).]]
[[File:Phylogenetic-Groups.svg|thumbnail|300px|Phylogenetic groups: A monophyletic taxon (in yellow, the clade [[Sauropsida]] grouping "reptiles and birds") contains a common ancestor and all of its descendants. A paraphyletic taxon (in cyan, the "reptiles") contains its most recent common ancestor, but does not contain all the descendants of that ancestor. A polyphyletic taxon (in red, the group [[Haemothermia]] containing [[Homeothermy|warm-blooded tetrapods]]) does not contain the most recent common ancestor of all its members.]]

A '''polyphyletic''' group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor.<ref>{{Cite book |last=Urry |first=Lisa A. |title=Campbell Biology |publisher=Pearson |year=2016 |isbn=978-0-134-09341-3 |edition=11th |pages=558}}</ref> The term is often applied to groups that share similar features known as [[Homoplasy|homoplasies]], which are explained as a result of [[convergent evolution]]. The arrangement of the members of a polyphyletic group is called a '''polyphyly''' {{IPAc-en|ˈ|p|ɒ|l|ɪ|ˌ|f|aɪ|l|i}}.<ref name="OED">{{Cite OED|polyphyly|access-date = 28 December 2021}}. [Source for pronunciation.]</ref> It is contrasted with [[monophyly]] and [[paraphyly]].

For example, the biological characteristic of [[warm-blooded]]ness evolved separately in the ancestors of mammals and the ancestors of birds; "warm-blooded animals" is therefore a polyphyletic grouping.<ref>{{Cite book |last=Archibald |first=J. David |url=https://books.google.com/books?id=VgkZBQAAQBAJ&pg=PA162 |title=Aristotle's Ladder, Darwin's Tree: The Evolution of Visual Metaphors for Biological Order |date=2014-07-15 |publisher=[[Columbia University Press]] |isbn=9780231164122 |language=en}}</ref> Other examples of polyphyletic groups are [[algae]], [[C4 photosynthesis|C4 photosynthetic plants]],<ref name="Sage-2004">{{Cite journal|last=Sage|first=Rowan F.|date=2004-02-01|title=The evolution of C4 photosynthesis |journal=[[New Phytologist]] |language=en |volume=161 |issue=2 |pages=341–370 |doi=10.1111/j.1469-8137.2004.00974.x |pmid=33873498 |issn=1469-8137|doi-access=free}}</ref> and [[Xenarthra#Evolutionary relationships|edentates]].<ref name="Delsuc2008">{{Cite book |last1=Delsuc |first1=Frédéric |title=The biology of the Xenarthra |last2=Douzery |first2=Emmanuel J. P. |publisher=[[University Press of Florida]] |year=2008 |isbn=9780813031651 |editor-last1=Vizcaíno |editor-first1=Sergio F. |location=Gainesville |pages=11–23 |chapter=Recent advances and future prospects in xenarthran molecular phylogenetics |oclc=741613153 |editor-last2=Loughry |editor-first2=W. J.}}</ref>

Many [[taxonomist]]s aim to avoid homoplasies in grouping taxa together, with a goal to identify and eliminate groups that are found to be polyphyletic. This is often the stimulus for major revisions of the classification schemes. Researchers concerned more with ecology than with systematics may take polyphyletic groups as legitimate subject matter; the similarities in activity within the fungus group ''[[Alternaria]]'', for example, can lead researchers to regard the group as a valid [[genus]] while acknowledging its polyphyly.<ref>{{cite journal |first1=Erik T. |last1=Aschehoug |first2=Kerry L. |last2=Metlen |first3=Ragan M. |last3=Callaway |first4=George |last4=Newcombe |year=2012 |title=Fungal endophytes directly increase the competitive effects of an invasive forb |journal=Ecology |volume=93 |issue=1 |pages=3–8 |doi=10.1890/11-1347.1 |pmid=22486080 |doi-access=free |bibcode=2012Ecol...93....3A }}</ref> In recent research, the concepts of monophyly, paraphyly, and polyphyly have been used in deducing key genes for [[DNA barcoding|barcoding]] of diverse groups of species.<ref>{{cite journal |doi=10.1016/j.gene.2019.143967 |pmid=31279710 |title=Diagnosis of mitogenome for robust phylogeny: A case of Cypriniformes fish group |journal=Gene |volume=713 |pages=143967 |year=2019 |last1=Parhi J., Tripathy P.S., Priyadarshi, H. |first1=Mandal S.C., Pandey P.K. |s2cid=195828782 }}</ref>