View source for Phylum

{{short description|High level taxonomic rank for organisms sharing a similar body plan}}
{{Other uses|Phyla (disambiguation)}}
{{pp-move}}
{{Use dmy dates|date=June 2020}}
{{Biological classification}}

In [[biology]], a '''phylum''' ({{IPAc-en|ˈ|f|aɪ|l|əm}}; {{plural form}}: '''phyla''') is a level of classification, or [[taxonomic rank]], that is below [[Kingdom (biology)|kingdom]] and above [[Class (biology)|class]]. Traditionally, in [[botany]] the term [[division (taxonomy)|division]] has been used instead of phylum, although the [[International Code of Nomenclature for algae, fungi, and plants]] accepts the terms as equivalent.<ref name="ICN">{{Cite book |year=2012 |editor-last=McNeill |editor-first=J. |display-editors=etal |title=International Code of Nomenclature for algae, fungi, and plants (Melbourne Code), Adopted by the Eighteenth International Botanical Congress Melbourne, Australia, July 2011 |edition=electronic |publisher=International Association for Plant Taxonomy |url=http://www.iapt-taxon.org/nomen/main.php?page=art3 |access-date=2017-05-14 |archive-date=10 October 2020 |archive-url=https://web.archive.org/web/20201010230658/https://www.iapt-taxon.org/nomen/main.php?page=art3 |url-status=dead }}</ref><ref>{{cite book|title=The American Heritage New Dictionary of Cultural Literacy|chapter-url=http://dictionary.reference.com/browse/phylum|access-date=2008-10-04|edition=third|year=2005|publisher=Houghton Mifflin Company|chapter=Life sciences
|quote=Phyla in the plant kingdom are frequently called divisions.}}</ref><ref name="Berg2007">{{cite book|last=Berg|first=Linda R.|title=Introductory Botany: Plants, People, and the Environment|url=https://books.google.com/books?id=I71WWH9ZmfsC&pg=PA15|access-date=2012-07-23|edition=2|date=2 March 2007 |publisher=Cengage Learning|isbn=9780534466695|page=15}}</ref> Depending on definitions, the animal kingdom [[Animalia]] contains about 31 phyla, the plant kingdom [[Plantae]] contains about 14 phyla, and the fungus kingdom [[Fungi]] contains about eight phyla. Current research in [[phylogenetics]] is uncovering the relationships among phyla within larger [[clades]] like [[Ecdysozoa]] and [[Embryophyta]].

== General description ==
The term phylum was coined in 1866 by [[Ernst Haeckel]] from the Greek {{Transliteration|grc|phylon}} ({{linktext|φῦλον|lang=grc}}, "race, stock"), related to {{Transliteration|grc|phyle}} ({{linktext|φυλή|lang=grc}}, "tribe, clan").{{sfn|Valentine|2004|p=8}}<ref>{{cite book |last1=Haeckel |first1=Ernst |title=Generelle Morphologie der Organismen |trans-title=The General Morphology of Organisms |date=1866 |publisher=G. Reimer |location=Berlin, (Germany) |volume=1 |pages=[https://archive.org/details/generellemorphol01haec/page/28 28]–29 |url=https://archive.org/details/generellemorphol01haec |language=de}}</ref> Haeckel noted that species constantly evolved into new species that seemed to retain few consistent features among themselves and therefore few features that distinguished them as a group ("a self-contained unity"): "perhaps such a real and completely self-contained unity is the aggregate of all species which have gradually evolved from one and the same common original form, as, for example, all vertebrates. We name this aggregate [a] {{lang|de|Stamm}} [i.e., stock / tribe] ({{lang|de|Phylon}})."{{efn| {{lang|de|"Wohl aber ist eine solche reale und vollkommen abgeschlossene Einheit die Summe aller Species, welche aus einer und derselben gemeinschaftlichen Stammform allmählig sich entwickelt haben, wie z. B. alle Wirbelthiere. Diese Summe nennen wir Stamm (Phylon)."}}}} In [[plant taxonomy]], [[August W. Eichler]] (1883) classified plants into [[Eichler system|five groups]] named divisions, a term that remains in use today for groups of plants, algae and fungi.<ref name=ICN/><ref>{{cite book |last=Naik |first=V. N. |year=1984 |page=27 |title=Taxonomy of Angiosperms |publisher=Tata McGraw-Hill |isbn=9780074517888 |url=https://books.google.com/books?id=GanmtXAyU0gC}}</ref>
The definitions of zoological phyla have changed from their origins in the six [[Linnaean taxonomy|Linnaean]] classes and the four {{lang|fr|embranchements}} of [[Georges Cuvier]].<ref>{{cite journal |vauthors=Collins AG, Valentine JW |year=2001 |url=http://si-pddr.si.edu/jspui/bitstream/10088/7403/1/Collins_Valentine_EvDev2001.pdf |title=Defining phyla: evolutionary pathways to metazoan body plans |journal=Evolution and Development |volume=3 |pages=432–442 |access-date=5 March 2013 |archive-date=27 April 2020 |archive-url=https://web.archive.org/web/20200427032535/https://repository.si.edu/handle/10088/7403 |url-status=dead }}</ref>

Informally, phyla can be thought of as groupings of organisms based on general specialization of [[body plan]].<ref>{{cite book |last=Valentine |first=James W. |year=2004 |title=On the Origin of Phyla |publisher=University of Chicago Press |location=Chicago |isbn=978-0-226-84548-7 |page=7 |quote=Classifications of organisms in hierarchical systems were in use by the seventeenth and eighteenth centuries. Usually, organisms were grouped according to their morphological similarities as perceived by those early workers, and those groups were then grouped according to their similarities, and so on, to form a hierarchy.}}</ref> At its most basic, a phylum can be defined in two ways: as a group of organisms with a certain degree of morphological or developmental similarity (the [[phenetic]] definition), or a group of organisms with a certain degree of evolutionary relatedness (the [[phylogenetic]] definition).<ref name="Budd2000">{{cite journal |last1=Budd |first1=G. E. |last2=Jensen |first2=S. |date=May 2000 |title=A critical reappraisal of the fossil record of the bilaterian phyla |journal=Biological Reviews |volume=75 |issue=2 |pages=253–295 |doi=10.1111/j.1469-185X.1999.tb00046.x |url=http://www.journals.cambridge.org/abstract_S000632310000548X |pmid=10881389 |s2cid=39772232 |access-date=26 May 2007 |archive-date=15 September 2019 |archive-url=https://web.archive.org/web/20190915160434/https://www.cambridge.org/core/journals/biological-reviews/article/critical-reappraisal-of-the-fossil-record-of-the-bilaterian-phyla/84D1DF6738A47E565B400A50590E15E2 |url-status=dead |url-access=subscription }}</ref> Attempting to define a level of the [[Linnaean taxonomy|Linnean hierarchy]] without referring to (evolutionary) relatedness is unsatisfactory, but a phenetic definition is useful when addressing questions of a morphological nature—such as how successful different body plans were.{{citation needed|date=May 2017}}

=== Definition based on genetic relation ===

The most important objective measure in the above definitions is the "certain degree" that defines how different organisms need to be members of different phyla. The minimal requirement is that all organisms in a phylum should be clearly more closely related to one another than to any other group.<ref name=Budd2000/> Even this is problematic because the requirement depends on knowledge of organisms' relationships: as more data become available, particularly from molecular studies, we are better able to determine the relationships between groups. So phyla can be merged or split if it becomes apparent that they are related to one another or not. For example, the [[Siboglinidae|bearded worms]] were described as a new phylum (the Pogonophora) in the middle of the 20th century, but molecular work almost half a century later found them to be a group of [[annelid]]s, so the phyla were merged (the bearded worms are now an annelid [[Family (biology)|family]]).<ref>{{cite journal |last=Rouse |first=G. W. |title=A cladistic analysis of Siboglinidae Caullery, 1914 (Polychaeta, Annelida): formerly the phyla Pogonophora and Vestimentifera | journal=Zoological Journal of the Linnean Society | volume=132 | issue=1| year=2001 | pages=55–80 | doi = 10.1006/zjls.2000.0263| doi-access=free }}</ref> On the other hand, the highly parasitic phylum [[Mesozoa]] was divided into two phyla ([[Orthonectida]] and [[Rhombozoa]]) when it was discovered the Orthonectida are probably [[deuterostome]]s and the Rhombozoa [[protostome]]s.<ref>{{cite journal |vauthors=Pawlowski J, Montoya-Burgos JI, Fahrni JF, Wüest J, Zaninetti L |title=Origin of the Mesozoa inferred from 18S rRNA gene sequences |journal=Molecular Biology and Evolution |volume=13 |issue=8 |pages=1128–32 |date=October 1996 |pmid=8865666 |doi=10.1093/oxfordjournals.molbev.a025675|doi-access=free }}</ref>

This changeability of phyla has led some biologists to call for the concept of a phylum to be abandoned in favour of placing taxa in [[clade]]s without any formal ranking of group size.<ref name=Budd2000/>

=== Definition based on body plan ===
A definition of a phylum based on body plan has been proposed by [[Paleontology|paleontologists]] [[Graham Budd]] and [[Sören Jensen]] (as Haeckel had done a century earlier). The definition was posited because extinct organisms are hardest to classify: they can be offshoots that diverged from a phylum's line before the characters that define the modern phylum were all acquired. By Budd and Jensen's definition, a phylum is defined by a set of characters shared by all its living representatives.

This approach brings some small problems—for instance, ancestral characters common to most members of a phylum may have been lost by some members. Also, this definition is based on an arbitrary point of time: the present. However, as it is character based, it is easy to apply to the fossil record. A greater problem is that it relies on a subjective decision about which groups of organisms should be considered as phyla.

The approach is useful because it makes it easy to classify extinct organisms as "[[stem group]]s" to the phyla with which they bear the most resemblance, based only on the taxonomically important similarities.<ref name=Budd2000/> However, proving that a fossil belongs to the [[crown group]] of a phylum is difficult, as it must display a character unique to a sub-set of the crown group.<ref name=Budd2000/> Furthermore, organisms in the stem group of a phylum can possess the "body plan" of the phylum without all the characteristics necessary to fall within it. This weakens the idea that each of the phyla represents a distinct body plan.<ref name=Budd1998>{{Cite journal | last = Budd | first = G. E. | date = September 1998 | journal = Lethaia | title = Arthropod body-plan evolution in the Cambrian with an example from anomalocaridid muscle | volume = 31 | issue = 3 | pages = 197–210 | doi = 10.1111/j.1502-3931.1998.tb00508.x}}</ref>

A classification using this definition may be strongly affected by the chance survival of rare groups, which can make a phylum much more diverse than it would be otherwise.<ref name="Briggs2005">{{Cite journal |year=2005 |title=Wonderful strife: systematics, stem groups, and the phylogenetic signal of the Cambrian radiation |journal=Paleobiology |volume=31 |issue=2 (Suppl) |pages=94–112 |doi=10.1666/0094-8373(2005)031[0094:WSSSGA]2.0.CO;2 |last1=Briggs |first1=D. E. G. |author1-link = Derek Briggs |last2=Fortey |first2=R. A. |s2cid=44066226 |author-link2 = Richard Fortey}}</ref>

== Known phyla ==

=== Animals ===
{{main|Animal}}
{{More citations needed section|date=February 2013}}

Total numbers are estimates; figures from different authors vary wildly, not least because some are based on described species,<ref name="Zhang2013">{{cite journal|last=Zhang|first=Zhi-Qiang|date=2013-08-30|title=Animal biodiversity: An update of classification and diversity in 2013. In: Zhang, Z.-Q. (Ed.) Animal Biodiversity: An Outline of Higher-level Classification and Survey of Taxonomic Richness (Addenda 2013)|url=https://biotaxa.org/Zootaxa/article/download/zootaxa.3703.1.3/4273|journal=Zootaxa|volume=3703|issue=1|page=5|doi=10.11646/zootaxa.3703.1.3|doi-access=free}}</ref> some on extrapolations to numbers of undescribed species. For instance, around 25,000–27,000 species of nematodes have been described, while published estimates of the total number of nematode species include 10,000–20,000; 500,000; 10 million; and 100 million.<ref name=Felder2009>{{cite book |last1=Felder |first1=Darryl L. |last2=Camp |first2=David K. |title=Gulf of Mexico Origin, Waters, and Biota: Biodiversity |url=https://books.google.com/books?id=CphA8hiwaFIC&pg=RA1-PA1111 |year=2009 |publisher=Texas A&M University Press |isbn=978-1-60344-269-5 |page=1111}}</ref>

{| class="wikitable"
|-
  | style="background: #ffe0e0" width="15%"|
  | [[Protostome]]
  |rowspan="4"| [[Bilateria]]
  |rowspan="2"| [[Nephrozoa]]
|-
  | style="background: #f8de7e"|
  | [[Deuterostome]]
|-
  | style="background: #a0b0d0"|
  | Basal/disputed
|-
  | style="background: #f8be9a"|
  | [[Vendobionta]]
|-
  | style="background: #bebebe"|
  |colspan="2"| Others
|}

{| class="wikitable sortable mw-collapsible"
!Phylum!!Meaning!!Common name!!Distinguishing characteristic!!Taxa described
|-style="background: #bebebe"
|[[Agmata]]
|Fragmented
|
|Calcareous conical shells
|5 species, extinct
|- style="background: #ffe0e0"
|[[Annelida]]
|Little ring <ref name="K&D">{{cite book | last1 = Margulis | first1 = Lynn | author-link = Lynn Margulis | last2 = Chapman
 | first2 = Michael J. | title = Kingdoms and Domains: An Illustrated Guide to the Phyla of Life on Earth | publisher = Academic Press | edition = 4th corrected | date = 2009 | location = London | isbn = 9780123736215 | url=https://books.google.com/books?id=9IWaqAOGyt4C}}</ref>{{rp|306}}
|Segmented worms, annelids
|Multiple circular segments
|{{nts|22000}}+ extant
|- style="background: #ffe0e0"
|[[Arthropoda]]
|Jointed foot
|Arthropods
|Segmented bodies and jointed limbs, with [[Chitin]] [[exoskeleton]]
|{{nts|1250000}}+ extant;<ref name="Zhang2013" /> 20,000+ extinct
|- style="background: #ffe0e0"
|[[Brachiopoda]]
|Arm foot<ref name="K&D" />{{rp|336}}
|Lampshells<ref name="K&D" />{{rp|336}}
|[[Lophophore]] and [[Brachiopod#pedicle|pedicle]]
|{{nts|300}}–500 extant; 12,000+ extinct<!--Please do not change data without providing a reliable source-->
|- style="background: #ffe0e0"
|[[Bryozoa]] ([[Ectoprocta]])
|Moss animals
|Moss animals, sea mats, ectoprocts<ref name="K&D" />{{rp|332}}
|Lophophore, no pedicle, [[cilia]]ted [[tentacle]]s, anus outside ring of cilia
|{{nts|6000}} extant<ref name="Zhang2013"/>
|- style="background: #ffe0e0"
|[[Chaetognatha]]
|Longhair jaw
|Arrow worms<ref name="K&D" />{{rp|342}}
|[[Chitin]]ous spines either side of head, fins
|{{nts|100|prefix={{abbr|approx.|approximately}}&nbsp;}} extant<!--Please do not change data without providing a reliable source-->
|- style="background: #f8de7e"
|[[Chordata]]
|With a cord
|Chordates
|Hollow [[dorsal nerve cord]], [[notochord]], [[pharyngeal slit]]s, [[endostyle]], post-[[anus|anal]] [[tail]]
|{{nts|55000|prefix=approx.&nbsp;}}+<ref name="Zhang2013"/>
|- style="background: #bebebe"
|[[Cnidaria]]
|Stinging nettle
| Cnidarians
|[[Nematocysts]] (stinging cells)
|{{nts|16000|prefix=approx.&nbsp;}}<ref name="Zhang2013"/>
|- style="background: #bebebe"
|[[Ctenophora]]
|Comb bearer
|Comb jellies<ref name="K&D" />{{rp|256}}
|Eight "comb rows" of fused cilia
|{{nts|100|prefix=approx.&nbsp;}}–150 extant<!--Please do not change data without providing a reliable source-->
|- style="background: #ffe0e0"
|[[Cycliophora]]
|Wheel carrying
|
|Circular mouth surrounded by small cilia, sac-like bodies
|{{nts|3}}+
|- style="background: #ffe0e0"
|[[Dicyemida]]
|Lozenge animal
|
|Single [[Anatomical terms of location|anteroposterior]] [[Axis of rotation|axial]] [[cell (biology)|celled]] endoparasites, surrounded by ciliated cells
|{{nts|100}}+
|- style="background: #f8de7e"
|[[Echinodermata]]
|Spiny skin
|Echinoderms<ref name="K&D" />{{rp|348}}
|Fivefold radial [[symmetry]] in living forms, [[germ layer#Mesoderm|mesodermal]] calcified spines
|{{nts|7500|prefix=approx.&nbsp;}} extant;<ref name="Zhang2013"/> approx. 13,000 extinct
|- style="background: #ffe0e0"
|[[Entoprocta]]
|Inside [[anus]]<ref name="K&D" />{{rp|292}}
|Goblet worms
|Anus inside ring of cilia
|{{nts|150|prefix=approx.&nbsp;}}
|- style="background: #ffe0e0"
|[[Gastrotricha]]
|Hairy stomach<ref name="K&D" />{{rp|288}}
|Hairybellies
|Two terminal adhesive tubes
|{{nts|690|prefix=approx.&nbsp;}}
|- style="background: #ffe0e0"
|[[Gnathostomulida]]
|Jaw orifice
|Jaw worms<ref name="K&D" />{{rp|260}}
|Tiny worms related to rotifers with no body cavity
|{{nts|100|prefix=approx.&nbsp;}}
|- style="background: #f8de7e"
|[[Hemichordata]]
|Half cord<ref name="K&D" />{{rp|344}}
|Acorn worms, hemichordates
|[[Stomochord]] in collar, [[pharyngeal slit]]s
|{{nts|130|prefix=approx.&nbsp;}} extant
|- style="background: #ffe0e0"
|[[Kinorhyncha]]
|Motion snout
|Mud dragons
|Eleven segments, each with a dorsal plate
|{{nts|150|prefix=approx.&nbsp;}}
|- style="background: #ffe0e0"
|[[Loricifera]]
|[[Armour]] bearer <!--Lorica is Roman armour -->
|Brush heads
|Umbrella-like scales at each end
|{{nts|122|prefix=approx.&nbsp;}}
|- style="background: #ffe0e0"
|[[Limnognathia|Micrognathozoa]]
|Tiny jaw animals
|
|[[Accordion]]-like extensible [[thorax]]
|{{nts|2}}
|- style="background: #ffe0e0"
|[[Mollusca]]
|Soft<ref name="K&D" />{{rp|320}}
|Mollusks/molluscs
|Muscular foot and [[Mantle (mollusc)|mantle]] round shell
|{{nts|85000}}+ extant;<ref name="Zhang2013"/> 80,000+ extinct<ref>Feldkamp, S. (2002) ''Modern Biology''. Holt, Rinehart, and Winston, USA. (pp. 725)</ref>
|- style="background: #bebebe"
|[[Monoblastozoa]] <br> <small>(''[[Nomen inquirendum]]'')</small>
|One sprout animals
|
| distinct anterior/posterior parts and being densely ciliated, especially around the "mouth" and "anus".
|1
|- style="background: #ffe0e0"
|[[Nematoda]]
|Thread like
|Roundworms, threadworms, eelworms, nematodes<ref name="K&D" />{{rp|274}}
|Round cross section, [[keratin]] [[cuticle]]
|{{nts|25000}}<ref name="Zhang2013"/>
|- style="background: #ffe0e0"
|[[Nematomorpha]]
|Thread form<ref name="K&D" />{{rp|276}}
|Horsehair worms, Gordian worms<ref name="K&D" />{{rp|276}}
|Long, thin parasitic worms closely related to nematodes
|{{nts|320|prefix=approx.&nbsp;}}
|- style="background: #ffe0e0"
|[[Nemertea]]
|A sea nymph<ref name="K&D" />{{rp|270}}
|Ribbon worms<ref name="K&D" />{{rp|270}}
|Unsegmented worms, with a proboscis housed in a cavity derived from the coelom called the rhynchocoel
|{{nts|1200|prefix=approx.&nbsp;}}
|- style="background: #ffe0e0"
|[[Onychophora]]
|Claw bearer
|Velvet worms<ref name="K&D" />{{rp|328}}
|Worm-like animal with legs tipped by chitinous claws
|{{nts|200|prefix=approx.&nbsp;}} extant
|- style="background: #ffe0e0"
|[[Orthonectida]]
|Straight swimmer
|
| Parasitic, microscopic, simple, wormlike organisms
|20
|- style="background: #f8be9a"
|[[Petalonamae]]
|Shaped like leaves 
|
|An extinct phylum from the Ediacaran. They are bottom-dwelling and immobile, shaped like leaves (frondomorphs), feathers or spindles.
|3 classes, extinct
|- style="background: #ffe0e0"
|[[Phoronid]]a
|Zeus's mistress
|Horseshoe worms
|U-shaped gut
|{{nts|11}}
|- style="background: #a6ba9e"
|[[Placozoa]]
|Plate animals
|Trichoplaxes, placozoans<ref name="K&D" />{{rp|242}}
|Differentiated top and bottom surfaces, two ciliated cell layers, amoeboid fiber cells in between
|{{nts|4}}+
|- style="background: #bebebe"
|[[Platyhelminthes]]
|Flat worm<ref name="K&D" />{{rp|262}}
|Flatworms<ref name="K&D" />{{rp|262}}
|Flattened worms with no body cavity. Many are parasitic.
|{{nts|29500|prefix=approx.&nbsp;}}<ref name="Zhang2013"/>
|- style="background: #a6ba9e"
|[[Porifera]]
|Pore bearer
|Sponges<ref name="K&D" />{{rp|246}}
|Perforated interior wall, simplest of all known animals
|{{nts|10800}} extant<ref name="Zhang2013"/>
|- style="background: #bebebe"
|[[Priapulida]]
|Little [[Priapus]]
|Penis worms
|Penis-shaped worms
| {{nts|20|prefix=approx.&nbsp;}}
|- style="background: #f8be9a"
|[[Proarticulata]]
|Before articulates
|
|An extinct group of mattress-like organisms that display "glide symmetry." Found during the Ediacaran.
|3 classes, extinct
|- style="background: #ffe0e0"
|[[Rotifera]]
|Wheel bearer
|Rotifers<ref name="K&D" />{{rp|282}}
|Anterior crown of cilia
|{{nts|3500|prefix=approx.&nbsp;}}<ref name="Zhang2013"/>
|-style="background: #a0b0d0"
|[[Saccorhytida]]
|Saccus : "pocket" and "wrinkle"
|
|''Saccorhytus'' is only about 1&nbsp;mm (1.3&nbsp;mm) in size and is characterized by a spherical or hemispherical body with a prominent mouth.  Its body is covered by a thick but flexible cuticle.  It has a nodule above its mouth. Around its body are 8 openings in a truncated cone with radial folds. Considered to be a deuterostome<ref>{{Cite journal |last1=Han |first1=Jian |last2=Morris |first2=Simon Conway |last3=Ou |first3=Qiang |last4=Shu |first4=Degan |last5=Huang |first5=Hai |date=2017 |title=Meiofaunal deuterostomes from the basal Cambrian of Shaanxi (China) |url=https://www.nature.com/articles/nature21072 |journal=Nature |language=en |volume=542 |issue=7640 |pages=228–231 |doi=10.1038/nature21072 |pmid=28135722 |bibcode=2017Natur.542..228H |s2cid=353780 |issn=1476-4687|url-access=subscription }}</ref> or an early [[ecdysozoa]]n.<ref>{{Cite journal |last1=Liu |first1=Yunhuan |last2=Carlisle |first2=Emily |last3=Zhang |first3=Huaqiao |last4=Yang |first4=Ben |last5=Steiner |first5=Michael |last6=Shao |first6=Tiequan |last7=Duan |first7=Baichuan |last8=Marone |first8=Federica |last9=Xiao |first9=Shuhai |last10=Donoghue |first10=Philip C. J. |date=2022-08-17 |title=Saccorhytus is an early ecdysozoan and not the earliest deuterostome |url=https://www.nature.com/articles/s41586-022-05107-z |journal=Nature |volume=609 |issue=7927 |language=en |pages=541–546 |doi=10.1038/s41586-022-05107-z |pmid=35978194 |bibcode=2022Natur.609..541L |s2cid=251646316 |issn=1476-4687|hdl=1983/454e7bec-4cd4-4121-933e-abeab69e96c1 |hdl-access=free }}</ref>
|2 species, extinct
|- style="background: #ffe0e0"
|[[Tardigrada]]
|Slow step
|Water bears, moss piglets 
|Microscopic relatives of the arthropods, with a four segmented body and head
|{{nts|1000}}
|- style="background: #f8be9a"
|[[Trilobozoa]]
|Three-lobed animal
|Trilobozoans
|A taxon of mostly discoidal organisms exhibiting tricentric symmetry.  All are Ediacaran-aged
|18 genera, extinct
|-style="background: #f8de7e"
|[[Vetulicolia]]
|Ancient dweller 
|Vetulicolians
|Might possibly be a subphylum of the chordates. Their body consists of two parts: a large front part and covered with a large "mouth" and a hundred round objects on each side that have been interpreted as gills or openings near the pharynx.  Their posterior pharynx consists of 7 segments. 
|15 species, extinct
|- style="background: #a0b0d0"
|[[Xenacoelomorpha]]
|Strange hollow form
|Xenacoelomorphs
|Small, simple animals. [[Bilateria]]n, but lacking typical bilaterian structures such as gut cavities, anuses, and circulatory systems<ref name="Cannon2016">{{cite journal|last1=Cannon |first1=J.T. |last2=Vellutini |first2=B.C. |last3=Smith |first3=J. |last4=Ronquist |first4=F. |last5=Jondelius |first5=U. |last6=Hejnol |first6=A. |title=Xenacoelomorpha is the sister group to Nephrozoa |journal=Nature |volume=530 |issue=7588 |date=4 February 2016 |pages=89–93 |pmid=26842059 |doi=10.1038/nature16520|url=http://urn.kb.se/resolve?urn=urn:nbn:se:nrm:diva-1844 |bibcode=2016Natur.530...89C |s2cid=205247296 }}</ref>
|{{nts|400}}+
|-class="sortbottom"
|'''Total: 39'''
|
|
|
|'''1,525,000'''<ref name="Zhang2013"/>
|}

=== Plants ===
{{Main|Plant}}

The kingdom Plantae is defined in various ways by different biologists (see [[Plant#Current definitions of Plantae|Current definitions of Plantae]]). All definitions include the living [[embryophyte]]s (land plants), to which may be added the two green algae divisions, [[Chlorophyta]] and [[Charophyta]], to form the clade [[Viridiplantae]]. The table below follows the influential (though contentious) [[Cavalier-Smith's system of classification|Cavalier-Smith system]] in equating "Plantae" with [[Archaeplastida]],<ref name="6kingdoms">{{cite journal | last = Cavalier-Smith | first = Thomas | author-link = Thomas Cavalier-Smith | title = Only Six Kingdoms of Life | journal = Proceedings: Biological Sciences | volume = 271 | issue = 1545 | pages = 1251–1262 | date = 22 June 2004 | doi=10.1098/rspb.2004.2705| pmid = 15306349 | pmc = 1691724 }}</ref> a group containing Viridiplantae and the algal [[Rhodophyta]] and [[Glaucophyta]] divisions.

The definition and classification of plants at the division level also varies from source to source, and has changed progressively in recent years. Thus some sources place horsetails in division [[Arthrophyta]] and ferns in division [[Monilophyta]],{{sfn|Mauseth|2012|pp=514, 517}} while others place them both in Monilophyta, as shown below. The division [[Pinophyta]] may be used for all [[gymnosperm]]s (i.e. including cycads, ginkgos and gnetophytes),<ref name="Cronquist 1966 129–134">{{cite journal | last=Cronquist | first=A. |author2=A. Takhtajan |author3=W. Zimmermann  | date=April 1966 | title=On the higher taxa of Embryobionta | journal=Taxon | issue=4 | pages=129–134 | doi=10.2307/1217531 | volume=15 | jstor=1217531 }}</ref> or for conifers alone as below.

Since the first publication of the [[APG system]] in 1998, which proposed a classification of [[angiosperm]]s up to the level of [[order (biology)|order]]s, many sources have preferred to treat ranks higher than orders as informal clades. Where formal ranks have been provided, the traditional divisions listed below have been reduced to a very much lower level, e.g. [[subclass (biology)|subclass]]es.<ref>{{Citation |last1=Chase |first1=Mark W. |last2=Reveal |first2=James L. |date=October 2009 |title=A phylogenetic classification of the land plants to accompany APG III |journal=Botanical Journal of the Linnean Society |volume=161 |issue=2 |pages=122–127 |doi=10.1111/j.1095-8339.2009.01002.x |name-list-style=amp |doi-access=free }}</ref>

{| class="wikitable"
|-
| rowspan="3" |[[Archaeplastida]]
|[[Biliphyta]]<ref name="6kingdoms" />
|Other algae
| style="background: #bebebe" |
  
|-
| rowspan="2" |[[Viridiplantae]]
| [[Green algae]]
| style="background: #c2e085" |
  |-
| [[Embryophyte]] (Land plants)
  | style="background: #cbfdcb" width="15%" |
  
|}

{|class="wikitable sortable"
!Division!!Meaning!!Common name!!Distinguishing characteristics!!Species described
|- style="background: #cbfdcb"
| [[Anthocerotophyta]]<ref name = Mauseth489>{{cite book | last = Mauseth | first = James D. | title = Botany : An Introduction to Plant Biology | edition = 5th | year = 2012 | isbn = 978-1-4496-6580-7 | publisher = Jones and Bartlett Learning | location = Sudbury, MA}} p. 489</ref>
| ''[[Anthoceros]]''-like plants
| Hornworts
| Horn-shaped [[sporophyte]]s, no vascular system
| {{nts|100}}–300+
|- style="background: #cbfdcb"
| [[Moss|Bryophyta]]<ref name = Mauseth489/>
| ''[[Bryum]]''<!--is that right? Bruon is Greek for moss-->-like plants, moss plants
| Mosses
| Persistent unbranched [[sporophyte]]s, no vascular system
| {{nts|12000|prefix=approx.&nbsp;}}
|- style="background: #c2e085"
| [[Charophyta]]
| ''[[Chara (alga)|Chara]]''-like plants
| Charophytes
| 
| {{nts|1000|prefix=approx.&nbsp;}}
|- style="background: #c2e085"
| [[Chlorophyta]]
| (Yellow-)green plants<ref name="K&D" />{{rp|200}}
| Chlorophytes
|
| {{nts|7000|prefix=approx.&nbsp;}}
|- style="background: #cbfdcb"
| [[Cycadophyta]]{{sfn|Mauseth|2012|p=540}}
| ''[[Cycas]]''-like plants, palm-like plants
| Cycads
| Seeds, crown of compound leaves
| {{nts|100|prefix=approx.&nbsp;}}–200
|- style="background: #cbfdcb"
| [[Ginkgophyta]]{{sfn|Mauseth|2012|p=542}}
| ''[[Ginkgo]]''-like plants
| Ginkgophytes
| Seeds not protected by fruit
| {{nts|1|prefix=only&nbsp;}} extant; 50+ extinct
|- style="background: #bebebe"
| [[Glaucophyta]]
| Blue-green plants
| Glaucophytes
|
| {{nts|15}}
|- style="background: #cbfdcb"
| [[Gnetophyta]]{{sfn|Mauseth|2012|p=543}}
| ''[[Gnetum]]''-like plants
| Gnetophytes
| Seeds and woody vascular system with vessels
| {{nts|70|prefix=approx.&nbsp;}}
|- style="background: #cbfdcb"
| [[Lycophyta]]{{sfn|Mauseth|2012|p=509}}
|''[[Lycopodium]]''-like plants<br>
Wolf plants
| Clubmosses
|[[Microphyll]] [[leaf|leaves]], vascular system
| {{nts|1290}} extant
|- style="background: #cbfdcb"
| [[Flowering plant|Angiospermae]]
| Seed container
| Flowering plants, angiosperms
| Flowers and fruit, vascular system with vessels
| {{nts|300000}}
|- style="background: #cbfdcb"
| [[Marchantiophyta]],<ref name="Stotlers 2000">{{cite book | last1=Crandall-Stotler | first1=Barbara | last2=Stotler | first2=Raymond E. | year=2000 | chapter=Morphology and classification of the Marchantiophyta | page=21 |editor1=A. Jonathan Shaw |editor2=Bernard Goffinet | title=Bryophyte Biology | location=Cambridge | publisher=Cambridge University Press | isbn=978-0-521-66097-6 }}</ref><br>
Hepatophyta<ref name = Mauseth489/>
| ''[[Marchantia]]''-like plants<br>
Liver plants
| Liverworts
| Ephemeral unbranched [[sporophyte]]s, no vascular system
| {{nts|9000|prefix=approx.&nbsp;}}
|- style="background: #cbfdcb"
|[[Fern|Polypodiophyta]]
|''[[Polypodium]]''-like plants<br>
|Ferns
|[[Megaphyll]] [[leaf|leaves]], vascular system
| {{nts|10560|prefix=approx.&nbsp;}}
|- style="background: #bebebe"
|[[Picozoa]]
| Extremely small animals
|Picozoans, picobiliphytes
| 
|1
|- style="background: #cbfdcb"
| [[Pinophyta]],<ref name="Cronquist 1966 129–134"/><br>
Coniferophyta{{sfn|Mauseth|2012|p=535}}
|''[[Pinus]]''-like plants<br>
Cone-bearing plant
| Conifers
| Cones containing seeds and wood composed of tracheids
| {{nts|629}} extant
|- style="background: #bebebe"
|[[Prasinodermophyta]]
| [[Prasinoderma]]-like plants
|Picozoans, picobiliphytes, biliphytes
| 
|8
|- style="background: #bebebe"
|[[Rhodophyta]]
|Red plants
|Red algae
|Use [[phycobiliprotein]]s as [[accessory pigment]]s.
|{{nts|7000|prefix=approx.&nbsp;}}
|- wowowowk
|'''Total: 16'''
|
|
|
|}

=== Fungi ===
{{Main|Fungi}}

{|class="wikitable sortable"
!Division!!Meaning!!Common name!!Distinguishing characteristics!!Species described
|-
| [[Ascomycota]]
| Bladder fungus<ref name="K&D" />{{rp|396}}
| Ascomycetes,<ref name="K&D" />{{rp|396}} sac fungi
|Tend to have fruiting bodies (ascocarp).<ref>{{Cite journal|title=Advances in Applied Microbiology Chapter 2 - Fungal Spores for Dispersion in Space and Time|journal=Advances in Applied Microbiology|volume=85|pages=43–91 |last1=Wyatt |first1=T. |last2=Wösten |first2=H. |last3=Dijksterhuis |first3=J. |doi = 10.1016/B978-0-12-407672-3.00002-2|pmid=23942148|year=2013}}</ref> Filamentous, producing hyphae separated by septa. Can reproduce asexually.<ref>{{Cite web|url=https://courses.lumenlearning.com/boundless-biology/chapter/classifications-of-fungi/|title=Classifications of Fungi {{!}} Boundless Biology|website=courses.lumenlearning.com|access-date=2019-05-05}}</ref>
|30,000
|-
| [[Basidiomycota]]
| Small base fungus<ref name="K&D" />{{rp|402}}
| Basidiomycetes,<ref name="K&D" />{{rp|402}} club fungi
|Bracket fungi, toadstools, smuts and rust. Sexual reproduction.<ref name="courses.lumenlearning.com">{{cite web |title=Archaeal Genetics {{!}} Boundless Microbiology |url=https://courses.lumenlearning.com/boundless-microbiology/chapter/archaeal-genetics/ |website=courses.lumenlearning.com}}</ref>
| 31,515
|-
| [[Blastocladiomycota]]
| Offshoot branch fungus<ref>{{cite web
 | url = http://comenius.susqu.edu/biol/202/fungi/blastocladiomycota/default.htm
 | title = Blastocladiomycota
 | last1 = Holt
 | first1 = Jack R.
 | last2 = Iudica
 | first2 = Carlos A.
 | date = 1 October 2016
 | website = Diversity of Life
 | publisher = Susquehanna University
 | access-date = 29 December 2016}}</ref>
| Blastoclads
|
| Less than 200
|-
| [[Chytridiomycota]]
| Little cooking pot fungus<ref>{{cite web
 | url = http://comenius.susqu.edu/biol/202/fungi/chytridiomycota/default.htm
 | title = Chytridiomycota
 | last1 = Holt
 | first1 = Jack R.
 | last2 = Iudica
 | first2 = Carlos A.
 | date = 9 January 2014
 | website = Diversity of Life
 | publisher = Susquehanna University
 | access-date = 29 December 2016}}</ref>
| Chytrids
|Predominantly Aquatic [[Saprotrophic nutrition|saprotrophic]] or parasitic. Have a posterior [[flagellum]]. Tend to be single celled but can also be multicellular.<ref>{{Cite web|url=https://www.britannica.com/science/Chytridiomycota|title=Chytridiomycota {{!}} phylum of fungi|website=Encyclopedia Britannica|language=en|access-date=2019-05-05}}</ref><ref>{{Cite book|title=Physical Chemical Properties of Fungi|last=McConnaughey|first=M|doi = 10.1016/B978-0-12-801238-3.05231-4|year = 2014|isbn = 9780128012383}}</ref><ref>{{Cite journal|title=Fossil Fungi Chapter 4 - Chytridiomycota|last1=Taylor |last2=Krings |last3=Taylor|first1=Thomas |first2=Michael |first3=Edith|doi=10.1016/b978-0-12-387731-4.00004-9|year=2015|journal=Fossil Fungi|pages=41–67}}</ref>
|1000+
|-
| [[Glomeromycota]]
| Ball of yarn fungus<ref name="K&D" />{{rp|394}}
| Glomeromycetes, {{abbr|AM|arbuscular mycorrhizal}} fungi<ref name="K&D" />{{rp|394}}
|Mainly arbuscular mycorrhizae present, terrestrial with a small presence on wetlands. Reproduction is asexual but requires plant roots.<ref name="courses.lumenlearning.com"/>
|284
|-
| [[Microsporidia]]
| Small seeds<ref>{{cite web
 | url = http://comenius.susqu.edu/biol/202/fungi/microsporidia/default.htm
 | title = Microsporidia
 | last1 = Holt
 | first1 = Jack R.
 | last2 = Iudica
 | first2 = Carlos A.
 | date = 12 March 2013
 | website = Diversity of Life
 | publisher = Susquehanna University
 | access-date = 29 December 2016}}</ref>
| Microsporans<ref name="K&D" />{{rp|390}}
| 
| 1400
|-
| [[Neocallimastigomycota]]
| New beautiful whip fungus<ref>{{cite web
 | url = http://comenius.susqu.edu/biol/202/fungi/neocallimastigomycota/default.htm
 | title = Neocallimastigomycota
 | last1 = Holt
 | first1 = Jack R.
 | last2 = Iudica
 | first2 = Carlos A.
 | date = 23 April 2013
 | website = Diversity of Life
 | publisher = Susquehanna University
 | access-date = 29 December 2016}}</ref>
| Neocallimastigomycetes
|Predominantly located in digestive tract of herbivorous animals. Anaerobic, terrestrial and aquatic.<ref name="Types of Fungi">{{Cite web|url=https://biologywise.com/types-of-fungi|title=Types of Fungi|website=BiologyWise|date=22 May 2009|language=en-US|access-date=2019-05-05}}</ref>
| approx. 20 <ref name="Phylogeny of anaerobic fungi (phylum Neocallimastigomycota), with contributions from yak in China">{{cite journal |last1=Wang |first1=Xuewei |last2=Liu |first2=Xingzhong |last3=Groenewald |first3=Johannes Z. |title=Phylogeny of anaerobic fungi (phylum Neocallimastigomycota), with contributions from yak in China |journal=Antonie van Leeuwenhoek |date=2017 |volume=110 |issue=1 |pages=87–103 |doi=10.1007/s10482-016-0779-1 |pmid=27734254 |pmc=5222902 }}</ref>
|-
| [[Zygomycota]]
| Pair fungus<ref name="K&D" />{{rp|392}}
| Zygomycetes<ref name="K&D" />{{rp|392}}
|Most are saprobes and reproduce sexually and asexually.<ref name="Types of Fungi"/>
| approx. 1060
|-class="sortbottom"
|'''Total: 8'''
|
|
|
|}

Phylum Microsporidia is generally included in kingdom Fungi, though its exact relations remain uncertain,<ref name=Hibbett2007>{{cite journal | vauthors = Hibbett DS, Binder M, Bischoff JF, Blackwell M, Cannon PF, Eriksson OE, Huhndorf S, James T, Kirk PM, Lücking R, Thorsten Lumbsch H, Lutzoni F, Matheny PB, McLaughlin DJ, Powell MJ, Redhead S, Schoch CL, Spatafora JW, Stalpers JA, Vilgalys R, Aime MC, Aptroot A, Bauer R, Begerow D, Benny GL, Castlebury LA, Crous PW, Dai YC, Gams W, Geiser DM, Griffith GW, Gueidan C, Hawksworth DL, Hestmark G, Hosaka K, Humber RA, Hyde KD, Ironside JE, Kõljalg U, Kurtzman CP, Larsson KH, Lichtwardt R, Longcore J, Miadlikowska J, Miller A, Moncalvo JM, Mozley-Standridge S, Oberwinkler F, Parmasto E, Reeb V, Rogers JD, Roux C, Ryvarden L, Sampaio JP, Schüssler A, Sugiyama J, Thorn RG, Tibell L, Untereiner WA, Walker C, Wang Z, Weir A, Weiss M, White MM, Winka K, Yao YJ, Zhang N | display-authors = 6 | title = A higher-level phylogenetic classification of the Fungi | journal = Mycological Research | volume = 111 | issue = Pt 5 | pages = 509–47 | date = May 2007 | pmid = 17572334 | doi = 10.1016/j.mycres.2007.03.004 | url = http://www.clarku.edu/faculty/dhibbett/AFTOL/documents/AFTOL%20class%20mss%2023,%2024/AFTOL%20CLASS%20MS%20resub.pdf | url-status = dead | archive-url = https://web.archive.org/web/20090326135053/http://www.clarku.edu/faculty/dhibbett/AFTOL/documents/AFTOL%20class%20mss%2023%2C%2024/AFTOL%20CLASS%20MS%20resub.pdf | archive-date = 26 March 2009| citeseerx = 10.1.1.626.9582 | s2cid = 4686378 }}</ref> and it is considered a [[protozoa]]n by the International Society of Protistologists<ref name="Ruggiero2015" /> (see [[#Protista|Protista]], below). Molecular analysis of Zygomycota has found it to be [[polyphyletic]] (its members do not share an immediate ancestor),<ref>{{cite journal
 | last1 = White
 | first1 = Merlin M.
 | last2 = James
 | first2 = Timothy Y.
 | last3 = O'Donnell
 | first3 = Kerry
 | last4 = Cafaro
 | first4 = Matías J.
 | last5 = Tanabe
 | first5 = Yuuhiko
 | last6 = Sugiyama
 | first6 = Junta
 | display-authors = 3
 | title = Phylogeny of the Zygomycota Based on Nuclear Ribosomal Sequence Data
 | journal = Mycologia
 | volume = 98
 | issue = 6
 | pages = 872–884
 | date = Nov–Dec 2006
 | doi=10.1080/15572536.2006.11832617| pmid = 17486964
 | s2cid = 218589354
 }}</ref> which is considered undesirable by many biologists. Accordingly, there is a proposal to abolish the Zygomycota phylum. Its members would be divided between phylum Glomeromycota and four new subphyla ''[[incertae sedis]]'' (of uncertain placement): [[Entomophthoromycotina]], [[Kickxellomycotina]], [[Mucoromycotina]], and [[Zoopagomycotina]].<ref name=Hibbett2007 />

=== Protists ===
{{Main|Taxonomy of Protista}}

Kingdom [[Protista]] (or Protoctista) is included in the traditional five- or six-kingdom model, where it can be defined as containing all [[eukaryote]]s that are not plants, animals, or fungi.<ref name="K&D" />{{rp|120}} Protista is a [[paraphyletic]] taxon,<ref>{{cite journal| last = Hagen| first  = Joel B.| date = January 2012| title  = Five Kingdoms, More or Less: Robert Whittaker and the Broad Classification of Organisms| journal  = BioScience| volume = 62| issue  = 1 | pages  = 67–74| doi=10.1525/bio.2012.62.1.11| doi-access  = free}}</ref> which is less acceptable to present-day biologists than in the past. Proposals have been made to divide it among several new kingdoms, such as [[Protozoa]] and [[Chromista]] in the [[Cavalier-Smith's system of classification|Cavalier-Smith system]].<ref name="Reconciling">{{cite journal | last1 = Blackwell | first1 = Will H. | last2 = Powell | first2 = Martha J. | title = Reconciling Kingdoms with Codes of Nomenclature: Is It Necessary? | journal = Systematic Biology | volume = 48 | issue = 2 | pages = 406–412 | date = June 1999 | doi=10.1080/106351599260382| pmid = 12066717 | doi-access = free }}</ref>

Protist taxonomy has long been unstable,<ref>{{cite web | url = http://faculty.msj.edu/davisr/potpouri/protista.htm | title = Kingdom PROTISTA | last = Davis | first = R. A. | date = 19 March 2012 | website = College of Mount St. Joseph | access-date = 28 December 2016}}</ref> with different approaches and definitions resulting in many competing classification schemes. Many of the phyla listed below are used by the [[Catalogue of Life]],<ref name="CoLtree">{{cite web | url = http://www.catalogueoflife.org/col/browse/tree?de3fa845167fa2ccdac6ddcb6e8d9a28 | title = Taxonomic tree | date = 23 December 2016 | website = Catalogue of Life | access-date = 28 December 2016 | archive-date = 1 August 2021 | archive-url = https://web.archive.org/web/20210801083911/https://www.catalogueoflife.org/col/browse/tree?de3fa845167fa2ccdac6ddcb6e8d9a28 | url-status = dead }}</ref> and correspond to the Protozoa-Chromista scheme,<ref name="Ruggiero2015">{{cite journal | last1 = Ruggiero | first1 = Michael A. | last2 = Gordon | first2 = Dennis P. | last3 = Orrell | first3 = Thomas M. | last4 = Bailly | first4 = Nicholas | last5 = Bourgoin | first5 = Thierry | last6 = Brusca | first6 = Richard C. | last7 = Cavalier-Smith | first7 = Thomas | last8 = Guiry | first8 = Michael D. | last9 = Kirk | first9 = Paul M. | display-authors=3 | title = A Higher Level Classification of All Living Organisms | journal = PLOS ONE | volume = 10 | issue = 6 | date = 29 April 2015 | doi=10.1371/journal.pone.0119248 | pmid = 25923521 | pmc = 4418965 | page=e0119248| bibcode = 2015PLoSO..1019248R | doi-access = free }}</ref> with updates from the latest (2022) publication by [[Cavalier-Smith]].<ref name="Cavalier-Smith 2022">{{cite journal|vauthors=Cavalier-Smith T|title=Ciliary transition zone evolution and the root of the eukaryote tree: implications for opisthokont origin and classification of kingdoms Protozoa, Plantae, and Fungi|journal=Protoplasma|volume=259|pages=487–593|date=2022|doi=10.1007/s00709-021-01665-7|pmc=9010356}}</ref> Other phyla are used commonly by other authors, and are adapted from the system used by the International Society of Protistologists (ISP). Some of the descriptions are based on the 2019 revision of eukaryotes by the ISP.<ref name="Adl 2019">{{cite journal|vauthors=Adl SM, Bass D, Lane CE, Lukeš J, Schoch CL, Smirnov A, Agatha S, Berney C, Brown MW, Burki F, Cárdenas P, Čepička I, Chistyakova L, del Campo J, Dunthorn M, Edvardsen B, Eglit Y, Guillou L, Hampl V, Heiss AA, Hoppenrath M, James TY, Karnkowska A, Karpov S, Kim E, Kolisko M, Kudryavtsev A, Lahr DJ, Lara E, Le Gall L, Lynn DH, Mann DG, Massana R, Mitchell EA, Morrow C, Park JS, Pawlowski JW, Powell MJ, Richter DJ, Rueckert S, Shadwick L, Shimano S, Spiegel FW, Torruella G, Youssef N, Zlatogursky V, Zhang Q|year=2019|title=Revisions to the Classification, Nomenclature, and Diversity of Eukaryotes|journal=Journal of Eukaryotic Microbiology|volume=66|issue=1 |pages=4–119|doi=10.1111/jeu.12691|pmid=30257078 |pmc=6492006 }}</ref>

{| class="wikitable"
|-
  | style="background: #fff9a6" width="15%"|
  | [[Stramenopiles]]
| rowspan="4" |"[[Chromista]]"
|-
| style="background: #ffc8a6" width="15%"|
|[[Alveolata]]
|-
| style="background: #f8de7e" width="15%"|
|[[Rhizaria]]
|-
| style="background: #cfffa6" |
|"[[Hacrobia]]"
|-
  | style="background: #c5dafc" |
  | "[[Podiata|Sarcomastigota]]"
| rowspan="2" |"[[Protozoa]]"
|-
| style="background:#ffd4fe" |
|"[[Excavata]]"
|-
| style="background: #d6d6d6" width="15%"|
| colspan="2"| Orphan groups
|}

{|class="wikitable sortable"
!Phylum!!Meaning!!Common name!!Distinguishing characteristics!!Species described!!Image
|- style="background: #c5dafc"
| [[Amoebozoa]]
| Amorphous animals
| Amoebozoans
| Presence of [[pseudopodia]] for [[amoeboid]] movement, tubular [[crista]]e.<ref name="Adl 2019"/>
| {{nts|2400|prefix=approx.&nbsp;}}<ref name="Pawlowski_2012">{{cite journal | vauthors = Pawlowski J, Audic S, Adl S, Bass D, Belbahri L, Berney C, Bowser SS, Cepicka I, Decelle J, Dunthorn M, Fiore-Donno AM, Gile GH, Holzmann M, Jahn R, Jirků M, Keeling PJ, Kostka M, Kudryavtsev A, Lara E, Lukeš J, Mann DG, Mitchell EA, Nitsche F, Romeralo M, Saunders GW, Simpson AG, Smirnov AV, Spouge JL, Stern RF, Stoeck T, Zimmermann J, Schindel D, de Vargas C | display-authors = 6 | title = CBOL protist working group: barcoding eukaryotic richness beyond the animal, plant, and fungal kingdoms | journal = PLOS Biology | volume = 10 | issue = 11 | pages = e1001419 | date = November 6, 2012 | pmid = 23139639 | pmc = 3491025 | doi = 10.1371/journal.pbio.1001419 | doi-access = free }}</ref>
| [[File:Amoeba_proteus.jpg|100px]]
|- style="background: #ffc8a6"
| [[Apicomplexa]]
| Apical infolds<ref name="Apicomplexa"/>
| Apicomplexans, sporozoans
| Mostly parasitic, at least one stage of the life cycle with flattened subpellicular vesicles and a complete apical complex, non-photosynthetic [[apicoplast]].<ref name="Adl 2019"/> 
| {{nts|6000|prefix=over&nbsp;}}<ref name="Apicomplexa">{{cite book | vauthors = Votýpka J, Modrý D, Oborník M, Šlapeta J, Lukeš J | date = 2016| chapter = Apicomplexa | veditors = Archibald J, Simpson AG, Slamovits CH, Margulis L, Melkonian M, Chapman DJ, Corliss JO | title = Handbook of the Protists | publisher = Springer | publication-place = Cham | doi = 10.1007/978-3-319-32669-6_20-1}}</ref>
| [[File:Toxoplasma gondii.jpg|100px]]
|- style="background: #c5dafc"
| [[Apusozoa]]{{br}}{{small|([[paraphyletic]])}}
| ''[[Apusomonas]]''-like animals
| 
| [[gliding motility|Gliding]] bi[[flagellate|ciliates]] with two or three connectors between [[centriole]]s
| 32
| [[File:Podomonas_kaiyoae_C.jpg|100px]]
|- style="background: #fff9a6"
| [[Bigyra]]
| Two rings
| 
| [[Stramenopiles]] with a double helix in ciliary transition zone
| 
| [[File:Aplanonet3.jpg|100px]]
|- style="background: #f8de7e"
| [[Cercozoa]]
| Flagellated animal
| Cercozoans
| Defined by [[molecular phylogeny]], lacking distinctive morphological or behavioural characters.<ref name="Adl 2019"/>
| 
| [[File:Euglypha_sp.jpg|100px]]
|- style="background: #ffc8a6"
| [[Chromerida]]
| ''[[Chromera]]''-like organisms
| Chrompodellids, chromerids, colpodellids<ref name="Janouškovec 2015">{{cite Q|Q30662251}}</ref>
| Biflagellates, chloroplasts with four membranes, incomplete apical complex, cortical alveoli, tubular cristae.<ref name="Adl 2019" />
| 8<ref name="Guiry 2024"/>
| [[File:Vitrella_brassicaformis_LM_Michalek_2020.png|100px]]
|- style="background: #c5dafc"
| [[Choanozoa]]{{br}}{{small|([[paraphyletic]])}}
| Funnel animals<ref name="K&D"/>
| Opisthokont protists
| [[filopodia|Filose pseudopods]]; some with a [[choanoflagellate|colar of microvilli]] surrounding a [[flagellum]]
| {{nts|300|prefix=approx.&nbsp;}}<ref name="Pawlowski_2012"/>
| [[File:Desmarella_moniliformis.jpg|100px]]
|- style="background: #ffc8a6"
| [[Ciliophora]]
| Cilia bearers
| Ciliates
| Presence of multiple cilia and a [[cytostome]].
| {{nts|4500|prefix=approx.&nbsp;}}<ref name="Protist diversity">{{Cite book|url=https://www.springer.com/gp/book/9789048128006|title=Protist Diversity and Geographical Distribution|date=2009|publisher=Springer Netherlands|isbn=9789048128006|editor-last=Foissner|editor-first=W.|series=Topics in Biodiversity and Conservation|volume=8|pages=111|doi=10.1007/978-90-481-2801-3|language=en|editor-last2=Hawksworth|editor-first2=David}}</ref>
| [[File:Paramecium_bursaria.jpg|100px]]
|- style="background: #ddfa5a"
| [[Cryptista]]
| Hidden<ref name="K&D"/>
| 
| Defined by [[molecular phylogeny]], flat cristae.<ref name="Adl 2019"/>
| {{nts|246}}<ref name="Guiry 2024"/><ref name="Adl 2019"/>
| [[File:Rhodomonas_salina_CCMP_322.jpg|100px]]
|- style="background: #ffc8a6"
| [[Dinoflagellata]]
| Whirling flagellates<ref name="K&D"/>
| Dinoflagellates
| Biflagellates with a transverse ribbon-like flagellum with multiple waves beating to the cell’s left and a longitudinal flagellum beating posteriorly with only one or few waves.<ref name="Adl 2019"/>
| {{nts|2957}} extant{{br}}955 fossil<ref name="Guiry 2024"/>
| [[File:CSIRO ScienceImage 6736 dinoflagellate.jpg|100px]]
|- style="background: #f8de7e"
| [[Endomyxa]]
| Within mucus<ref name="K&D"/><ref name="Endomyxa">{{cite Q|Q28212529}}</ref>
| 
| Defined by [[molecular phylogeny]],<ref name="Adl 2019" /> typically plasmodial endoparasites of other eukaryotes.<ref name="Endomyxa"/>
|
| [[File:Vampyrella_lateritia.jpg|100px]]
|- style="background: #ffd4fe"
| [[Eolouka]]{{br}}{{small|([[paraphyletic]])}}
| Early groove<ref name="LSC">{{cite journal|vauthors=Cavalier-Smith T|date=2013|title=Early evolution of eukaryote feeding modes, cell structural diversity, and classification of the protozoan phyla Loukozoa, Sulcozoa, and Choanozoa|journal=European Journal of Protistology|volume=49|issue=2|pages=115–178|doi=10.1016/j.ejop.2012.06.001|pmid=23085100}}</ref>
| 
| Heterotrophic biflagellates with ventral feeding groove.<ref name="LSC"/>
| {{nts|23}}
| [[File:Stygiella incarcerata.jpg|100px]]
|- style="background: #ffd4fe"
| [[Euglenozoa]]
| True eye animals
|
| Biflagellates, one of the two [[cilia]] inserted into an apical or subapical pocket, unique ciliary configuration.<ref name="Adl 2019"/>
| {{nts|2037}} extant{{br}}20 fossil<ref name="Guiry 2024"/>
| [[File:Euglenoid_movement.jpg|100px]]
|- style="background: #fff9a6"
| [[Ochrophyta]],{{br}}[[Heterokontophyta]]
| [[Ochre]] plants, heterokont plants
| Heterokont algae, stramenochromes, ochrophytes, heterokontophytes
| Biflagellates with tripartite mastigonemes, chloroplasts with four membranes and chlorophylls ''a'' and ''c'', tubular cristae.<ref name="Adl 2019"/>
| {{nts|21052}} extant{{br}}2,262 fossil<ref name="Guiry 2024">{{cite Q|Q124684077}}</ref>
| [[File:Diatoms_through_the_microscope.jpg|100px]]
|- style="background: #ddfa5a"
| [[Haptista]]
| Fasten<ref name="K&D"/>
|
| Thin [[microtubule]]-based appendages for feeding (haptonema in [[haptophytes]],  [[axopodia]] in [[centrohelid]]s), complex mineralized scales.<ref name="Adl 2019"/>
| {{nts|517}} extant{{br}}1,205 fossil<ref name="Guiry 2024"/>
| [[File:Coccolithus_pelagicus_2.jpg|100px]]
|- style="background: #d6d6d6"
| [[Hemimastigophora]]
| Incomplete or atypical flagellates<ref name="Hemimastigophora"/>
| Hemimastigotes<ref>{{cite Q|Q58834974}}</ref>
| Ellipsoid or vermiform phagotrophs, two slightly spiraling rows of around 12 cilia each, thecal plates below the membrane supported by microtubules and rotationally symmetrical, tubular and saccular cristae.<ref name="Adl 2019"/><ref name="Hemimastigophora">{{cite Q|Q85570914}}</ref>
| {{nts|10}}<ref name="Spironematellidae">{{cite journal|first1=Yegor|last1=Shɨshkin|title=''Spironematella terricola'' comb. n. and ''Spironematella goodeyi'' comb. n. (Hemimastigida = Hemimastigea = Hemimastigophora) for ''Spironema terricola'' and ''Spironema goodeyi'' with diagnoses of the genus and family Spironematellidae amended|journal=Zootaxa|date=2022|volume=5128|issue=2|pages=295–297|doi=10.11646/zootaxa.5128.2.8|pmid=36101172|s2cid=252220401}}</ref>
|[[File:Hemimastix_amphikineta.png|60px]]
|- style="background: #ffd4fe"
| [[Malawimonada]]
| ''[[Malawimonas]]''-like organisms
| Malawimonads
| Small free-living bicilates with two kinetosomes, one or two vanes in posterior cilium.
| {{nts|3}}<ref name="Imasa heleensis">{{cite journal|vauthors=Heiss AA, Warring SD, Lukacs K, Favate J, Yang A, Gyaltshen Y, Filardi C, Simpson AG, Kim E|date=December 2020|title=Description of Imasa heleensis, gen. nov., sp. nov. (Imasidae, fam. nov.), a Deep-Branching Marine Malawimonad and Possible Key Taxon in Understanding Early Eukaryotic Evolution|journal=Journal of Eukaryotic Microbiology|volume=68|pages=e12837|doi=10.1111/jeu.12837}}</ref>
| [[File:Malawimonasms.jpg|100px]]
|- style="background: #ffd4fe"
| [[Metamonada]]
| Middle [[monad (biology)|monads]]
| Metamonads
| [[Anaerobic organism|Anaerobic]] or [[microaerophilic]], some without [[mitochondria]]; four [[kinetosome]]s per [[wikt:kinetid|kinetid]]
|
| [[File:Giardia muris trophozoite SEM 11643.jpg|100px]]
|- style="background: #c5dafc"
| [[Opisthosporidia]]<br>{{small|(often considered [[fungi]])}}
| [[Opisthokont]] spores<ref name="karpov">{{Cite journal|last1=Karpov|first1=Sergey|last2=Mamkaeva|first2=Maria A.|last3=Aleoshin|first3=Vladimir|last4=Nassonova|first4=Elena|last5=Lilje|first5=Osu|last6=Gleason|first6=Frank H.|date=2014-01-01|title=Morphology, phylogeny, and ecology of the aphelids (Aphelidea, Opisthokonta) and proposal for the new superphylum Opisthosporidia|journal= Frontiers in Microbiology|volume=5|pages=112|doi=10.3389/fmicb.2014.00112|pmc=3975115|pmid=24734027|doi-access=free}}</ref>
| 
| Parasites with [[chitin]]ous [[spore]]s and extrusive host-invasion apparatus
|
| [[File:Fibrillanosema_spore.jpg|100px]]
|- style="background: #ffd4fe"
| [[Percolozoa]]
| ''[[Percolomonas]]''-like animals
| 
| Complex [[biological life cycle|life cycle]] containing amoebae, flagellates and [[microbial cyst|cysts]].<ref name="Adl 2019"/>
|
| [[File:Naegleria fowleri lifecycle stages.JPG|100px]]
|- style="background: #ffc8a6"
| [[Perkinsozoa]]
| ''[[Perkinsus]]''-like animals
| Perkinsozoans, perkinsids
| Parasitic biflagellates, incomplete apical complex, formation of zoosporangia or undifferentiated cells via a hypha-like tube.<ref name="Adl 2019"/>
| {{nts|26}}
| [[File:Dinovorax_pyriformis_PMC5609580_fig1c.png|100px]]
|- style="background: #d6d6d6"
| [[Provora]]
| Devouring voracious protists<ref name="Provora"/>
| 
| Defined by [[molecular phylogeny]], free-living eukaryovorous heterotrophic biflagellates with ventral groove and extrusomes.<ref name="Provora">{{cite Q|Q115933632}}</ref>
| {{nts|7}}<ref name="Provora"/>
| [[File:Outline_drawing_of_Ubysseya_fretuma.svg|50px]]
|- style="background: #fff9a6"
| [[Pseudofungi]]
| False fungi
| 
| Defined by [[molecular phylogeny]], phagotrophic heterokonts with a helical ciliary transition zone.<ref name="Phagotrophic heterokonts">{{cite Q|Q28303534}}</ref>
| {{nts|1200|prefix=over&nbsp;}}<ref name="Oomycetes">{{cite journal|vauthors=Thines M|date=2018|title=Oomycetes|journal=Current Biology|volume=28|issue=15|pages=R812–R813|doi=10.1016/j.cub.2018.05.062|url=https://www.cell.com/current-biology/fulltext/S0960-9822(18)30698-5|doi-access=free}}</ref>
| [[File:Phytophthora_cactorum.jpg|100px]]
|- style="background: #f8de7e"
| [[Retaria]]
| Reticulopodia-bearing organisms<ref name="Endomyxa"/>
| 
| Feeding by [[reticulopodia]] (or [[axopodia]]) typically projected through various types of skeleton, closed mitosis.<ref name="Retaria">{{cite Q|Q28261633}}</ref>
| {{nts|10000}} extant{{br}}50,000 fossil
| [[File:Foraminifères_de_Ngapali.jpg|100px]]
|- style="background: #c5dafc"
| [[Sulcozoa]]{{br}}{{small|([[paraphyletic]])}}
| Groove-bearing animals<ref name="LSC"/>
| 
| [[Aerobic organism|Aerobic]] flagellates (none, 1, 2 or 4 flagella) with dorsal semi-rigid pellicle of one or two submembrane dense layers, ventral feeding groove, branching ventral pseudopodia, typically filose.<ref name="LSC"/>
| {{nts|40}}+
| [[File:Collodictyon_telophase_constrict.jpg|70px]]
|- style="background: #d6d6d6"
| [[Telonemia]]
| ''[[Telonema]]''-like organisms<ref name="Telonemia"/>
| Telonemids<ref name="Arpakorses"/>
| [[Phagotrophic]] pyriform biflagellates with a unique complex cytoskeleton, tubular cristae, tripartite mastigonemes, cortical alveoli.<ref name="Telonemia">{{cite journal |last1=Shalchian-Tabrizi |first1=K |last2=Eikrem |first2=W |last3=Klaveness |first3=D |last4=Vaulot |first4=D |last5=Minge |first5=M.A |last6=Le Gall |first6=F |last7=Romari |first7=K |last8=Throndsen |first8=J |last9=Botnen |first9=A |last10=Massana |first10=R |last11=Thomsen |first11=H.A |last12=Jakobsen |first12=K.S |title=Telonemia, a new protist phylum with affinity to chromist lineages |journal=Proceedings of the Royal Society B: Biological Sciences |date=28 April 2006 |volume=273 |issue=1595 |pages=1833–1842 |doi=10.1098/rspb.2006.3515 |pmid=16790418 |pmc=1634789 }}</ref><ref name="Arpakorses">{{cite journal | last1=Tikhonenkov | first1=Denis V. | last2=Jamy | first2=Mahwash | last3=Borodina | first3=Anastasia S. | last4=Belyaev | first4=Artem O. | last5=Zagumyonnyi | first5=Dmitry G. | last6=Prokina | first6=Kristina I. | last7=Mylnikov | first7=Alexander P. | last8=Burki | first8=Fabien | last9=Karpov | first9=Sergey A. | title=On the origin of TSAR: morphology, diversity and phylogeny of Telonemia | journal=Open Biology | publisher=The Royal Society | volume=12 | issue=3 | year=2022 | issn=2046-2441 | doi=10.1098/rsob.210325| pmid=35291881 | pmc=8924772 | doi-access=free }}</ref>
| {{nts|7}}
| [[File:Telonema_rivulare_(electron_micrography).jpg|100px]]
|-class="sortbottom"
| colspan="6"|'''Total: 26''', but see below.
|}

The number of protist phyla varies greatly from one classification to the next. The Catalogue of Life includes [[Rhodophyta]] and [[Glaucophyta]] in kingdom Plantae,<ref name="CoLtree" /> but other systems consider these phyla part of Protista.<ref>{{cite journal| last = Corliss| first  = John O.| date = 1984| title  = The Kingdom Protista and its 45 Phyla| journal  = BioSystems| volume = 17| issue  = 2| pages  = 87–176|doi=10.1016/0303-2647(84)90003-0| pmid = 6395918}}</ref> In addition, less popular classification schemes unite [[Ochrophyta]] and [[Pseudofungi]] under one phylum, [[Gyrista]], and all alveolates except [[ciliates]] in one phylum [[Myzozoa]], later lowered in rank and included in a paraphyletic phylum [[Miozoa]].<ref name="Cavalier-Smith 2022"/>  Even within a phylum, other phylum-level ranks appear, such as the case of [[Bacillariophyta]] (diatoms) within [[Ochrophyta]]. These differences became irrelevant after the adoption of a [[cladistic]] approach by the ISP, where taxonomic ranks are excluded from the classifications after being considered superfluous and unstable. Many authors prefer this usage, which lead to the Chromista-Protozoa scheme becoming obsolete.<ref name="Adl 2019"/>

=== Bacteria ===
{{main|Bacterial phyla}}

<!--COPY-PASTE FROM THERE-->
Currently there are 41 bacterial phyla (not including "[[Cyanobacteria]]") that have been validly published according to the [[Bacteriological Code]]<ref name="LPSN phyla">{{cite web | vauthors = Euzéby JP, Parte AC | url = https://lpsn.dsmz.de/text/names-of-phyla | title = Names of phyla | access-date = April 3, 2022 | publisher = [[List of Prokaryotic names with Standing in Nomenclature]] (LPSN)}}</ref>
# [[Abditibacteriota]]
# [[Acidobacteriota]], phenotypically diverse and mostly uncultured
# [[Actinomycetota]], High-G+C Gram positive species
# [[Aquificota]], deep-branching
# [[Armatimonadota]]
# [[Atribacterota]]
# [[Bacillota]], Low-G+C Gram positive species, such as the spore-formers [[Bacilli]] (aerobic) and [[Clostridia]] (anaerobic)
# [[Bacteroidota]]
# [[Balneolota]]
# [[Bdellovibrionota]]
# [[Caldisericota]], formerly candidate division OP5, ''Caldisericum exile'' is the sole representative
# [[Calditrichota]]
# [[Campylobacterota]]
# [[Chlamydiota]]
# [[Chlorobiota]], green sulphur bacteria
# [[Chloroflexota]], green non-sulphur bacteria
# [[Chrysiogenota]], only 3 genera (''Chrysiogenes arsenatis'', ''Desulfurispira natronophila'', ''Desulfurispirillum alkaliphilum'')
# [[Coprothermobacterota]]
# [[Deferribacterota]]
# [[Deinococcota]], ''Deinococcus radiodurans'' and ''Thermus aquaticus'' are "commonly known" species of this phyla
# [[Dictyoglomota]]
# [[Elusimicrobiota]], formerly candidate division Thermite Group 1
# [[Fibrobacterota]]
# [[Fusobacteriota]]
# [[Gemmatimonadota]]
# [[Ignavibacteriota]]
# [[Kiritimatiellota]]
# [[Lentisphaerota]], formerly clade VadinBE97
# [[Mycoplasmatota]], notable genus: ''[[Mycoplasma]]''
# [[Myxococcota]]
# [[Nitrospinota]]
# [[Nitrospirota]]
# [[Planctomycetota]]
# [[Pseudomonadota]], the most well-known phylum, containing species such as ''[[Escherichia coli]]'' or ''[[Pseudomonas aeruginosa]]''
# [[Rhodothermota]]
# [[Spirochaetota]], species include ''[[Borrelia burgdorferi]]'', which causes Lyme disease
# [[Synergistota]]
# [[Thermodesulfobacteriota]]
# [[Thermomicrobiota]]
# [[Thermotogota]], deep-branching
# [[Verrucomicrobiota]]

=== Archaea ===
{{main|Archaea}}
Currently there are 2 phyla that have been validly published according to the [[Bacteriological Code]]<ref name="LPSN phyla" />
# [[Nitrososphaerota]]
# [[Thermoproteota]], second most common archaeal phylum
Other phyla that have been proposed, but not validly named, include:
# "[[Euryarchaeota]]", most common archaeal phylum
# "[[Korarchaeota]]"
# "[[Nanoarchaeota]]", ultra-small symbiotes, single known species

== See also ==
{{portal|Biology}}
* [[Cladistics]]
* [[Phylogenetics]]
* [[Systematics]]
* [[Taxonomy (biology)|Taxonomy]]

== Notes ==
{{notelist}}

== References ==
{{reflist|30em}}

== External links ==
{{Wikispecies}}
{{Wiktionary|Phylum}}

* [https://web.archive.org/web/20060622202444/http://www.pandasthumb.org/archives/2005/04/down_with_phyla_1.html Are phyla "real"? Is there really a well-defined "number of animal phyla" extant and in the fossil record?]
* [http://waynesword.palomar.edu/trnov01.htm Major Phyla Of Animals] {{Webarchive|url=https://web.archive.org/web/20060716113027/http://waynesword.palomar.edu/trnov01.htm |date=16 July 2006 }}

{{Taxonomic ranks|state=expanded}}
{{Life on Earth}}
{{Authority control}}

[[Category:Phyla| ]]
[[Category:Plant divisions| ]]