Editing Paraphyly (section)

=== Paraphyly in species ===

{{main|Paraspecies}}

[[Species]] have a special status in systematics as being an observable feature of nature itself and as the basic unit of classification.<ref>{{cite journal |last1=Queiroz |first1=Kevin |last2=Donoghue |first2=Michael J. |title=Phylogenetic Systematics and the Species Problem |journal=Cladistics |date=December 1988 |volume=4 |issue=4 |pages=317–338 |doi= 10.1111/j.1096-0031.1988.tb00518.x |pmid=34949064 |s2cid=40799805 }}</ref> Some articulations of the [[Species#Phylogenetic or cladistic species|phylogenetic species concept]] require species to be monophyletic, but paraphyletic species are common in nature, to the extent that they do not have a single common ancestor. Indeed, for sexually reproducing taxa, no species has a "single common ancestor" organism. Paraphyly is common in [[speciation]], whereby a mother species (a [[paraspecies]]) gives rise to a daughter species without itself becoming extinct.<ref name= "AlbertReis2011">{{cite book |first1=James S.| last1= Albert | first2= Roberto E.| last2= Reis |title=Historical Biogeography of Neotropical Freshwater Fishes |url=https://books.google.com/books?id=_Suu7a-ERdMC&pg=PA308 |access-date=28 June 2011 |date=8 March 2011 |publisher= University of California Press |page=308 |isbn=978-0-520-26868-5| via= Google Books}}</ref> Research indicates as many as 20 percent of all animal species and between 20 and 50 percent of plant species are paraphyletic.<ref>{{cite journal |last1= Ross |first1= Howard A. |title= The incidence of species-level paraphyly in animals: A re-assessment |journal=Molecular Phylogenetics and Evolution |date= July 2014 |volume=76 |pages=10–17 |doi=10.1016/j.ympev.2014.02.021 |pmid=24583289}}</ref><ref>{{cite journal |last1=Crisp |first1=M.D. |last2=Chandler |first2=G.T. |title=Paraphyletic species |journal= [[Telopea (journal)|Telopea]] |date=1 July 1996 |volume= 6 |issue=4 |pages=813–844 |doi=10.7751/telopea19963037 |url= http://plantnet.rbgsyd.nsw.gov.au/emuwebnswlive/objects/common/webmedia.php?irn=75865&reftable=ebibliography |access-date=22 January 2015|doi-access=free }}</ref> Accounting for these facts, some taxonomists argue that paraphyly is a trait of nature that should be acknowledged at higher taxonomic levels.<ref>{{cite book |title=Framework for Post-Phylogenetic Systematics |last=Zander |first=Richard  |year=2013 |publisher=Zetetic Publications, Amazon CreateSpace |location=St. Louis |url= https://www.academia.edu/9137481 }}</ref><ref name="aub15">{{cite journal | last1=Aubert | first1=D. | year=2015 | title=A formal analysis of phylogenetic terminology: Towards a reconsideration of the current paradigm in systematics | journal= [[Phytoneuron]] | volume=66 | pages=1–54 }}</ref>

Cladists advocate a phylogenetic species concept <ref>{{cite journal| last1= Nixon| first1= Kevin C.| first2= Quentin D. |last2= Wheeler| title= An amplification of the phylogenetic species concept| journal= Cladistics |volume= 6| number= 3 |year= 1990| pages= 211–23| doi= 10.1111/j.1096-0031.1990.tb00541.x| s2cid= 84095773| doi-access= free}}</ref> that does not consider species to exhibit the properties of monophyly or paraphyly, concepts under that perspective which apply only to groups of species.<ref>{{cite book| last1= Brower| first1= Andrew V. Z. |first2= Randall T.| last2= Schuh| year= 2021| title= Biological Systematics: principles and applications| edition= 3rd| publisher= Cornell University Press| place= Ithaca, New York| isbn= 978-1-5017-5277-3}}</ref> They consider Zander's extension of the "paraphyletic species" argument to higher taxa to represent a [[category error]]<ref>{{cite journal| last= Schmidt-Lebuhn| first= Alexander N. |title= Fallacies and false premises—a critical assessment of the arguments for the recognition of paraphyletic taxa in botany| journal= Cladistics |volume= 28| number= 2 |year= 2012| pages= 174–87| doi= 10.1111/j.1096-0031.2011.00367.x | pmid= 34861757 | s2cid= 83900580 | doi-access= free }}</ref>