Editing Paraphyly (section)

{{Short description|Type of taxonomic group}}
{{Use dmy dates|date=November 2019}}
[[File:Clade-grade II.svg|thumb|300px|In this [[phylogenetic tree]], the green group is ''paraphyletic''; it is composed of a common ancestor (the lowest green vertical stem) and some of its descendants, but it excludes the blue group (a monophyletic group) which [[Divergent evolution|diverged]] from the green group.]]

'''Paraphyly''' is a [[taxonomy (general)|taxonomic]] term describing a grouping that consists of the grouping's [[most recent common ancestor|last common ancestor]] and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In contrast, a [[Monophyly|monophyletic]] grouping (a [[clade]]) includes a common ancestor and ''all'' of its descendants.

The terms are commonly used in [[phylogenetics]] (a subfield of [[biology]]) and in the [[tree model]] of [[historical linguistics]]. Paraphyletic groups are identified by a combination of [[Synapomorphy and apomorphy|synapomorphies]] and [[symplesiomorphy|symplesiomorphies]]. If many subgroups are missing from the named group, it is said to be polyparaphyletic.

The term received currency during the debates of the 1960s and 1970s accompanying the rise of [[cladistics]], having been coined by zoologist [[Willi Hennig]] to apply to well-known taxa like Reptilia ([[reptile]]s), which is paraphyletic with respect to [[bird]]s. Reptilia contains the last common ancestor of reptiles and all descendants of that ancestor except for birds. Other commonly recognized paraphyletic groups include [[fish]],<ref>{{Cite journal |last=Greene |first=Harry W. |date=1998-01-01 |title=We are primates and we are fish: Teaching monophyletic organismal biology |journal=Integrative Biology |volume=1 |issue=3 |pages=108–111 |doi=10.1002/(sici)1520-6602(1998)1:3<108::aid-inbi5>3.0.co;2-t |issn=1520-6602}}</ref> [[monkey]]s,<ref>{{Cite web |url=https://www.geol.umd.edu/~tholtz/G204/lectures/204scatterlings.html|title=The fossil record: the scatterlings of Africa: the origins of humanity |first=Thomas R. |last=Holtz |publisher=University of Maryland |access-date=6 February 2019}}</ref> and [[lizard]]s.<ref>{{cite journal |last1=Reeder |first1=Tod W. |last2=Townsend |first2=Ted M. |last3=Mulcahy |first3=Daniel G. |last4=Noonan |first4=Brice P.|last5=Wood |first5=Perry L. |last6=Sites |first6=Jack W. |last7=Wiens |first7=John J.|title=Integrated Analyses Resolve Conflicts over Squamate Reptile Phylogeny and Reveal Unexpected Placements for Fossil Taxa |journal=PLOS ONE |date=2015 |volume=10 |issue=3 |pages=e0118199 |doi=10.1371/journal.pone.0118199 |pmid=25803280|pmc=4372529|bibcode=2015PLoSO..1018199R |doi-access=free }}</ref>