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-{{taxobox
-| color = greenyellow
-| name = Chromalveolata
-| image = Chromista collage 2.jpg
-| image_width = 300px
-| image_caption = Clockwise from top-left: a [[haptophyte]], some [[diatom]]s, a [[water mold]], a [[cryptomonad]], and ''[[Macrocystis]]'', a [[phaeophyte]]
-| domain = [[Eukarya]]
-{{Taxobox_norank_entry | taxon = [[Bikonta]]}}
-| unranked_regnum = [[Corticata]]
-| regnum = '''Chromalveolata'''[[paraphyly|*]]
-| subdivision_ranks = Phyla
-| subdivision = *[[Heterokont]]ophyta
-*[[Haptophyta]]
-*[[Cryptophyta]]
-*'''[[Alveolata]]''' (Superphylum)
-**[[Apicomplexa]]
-**[[Chromerida]]
-**[[Ciliophora]]
-**[[Dinoflagellata]]
-}}
-'''Chromalveolata''' is a [[eukaryote]] supergroup first proposed by [[Thomas Cavalier-Smith]] as a refinement of his [[kingdom (biology)|kingdom]] [[Chromista]], which was first put forward in 1981.  Chromalveolata was proposed to represent the result of a single secondary [[endosymbiosis]] between a line descending from a [[bikont]] and a [[red alga]]<ref name="pmid19335769">{{cite journal |author=Keeling PJ |title=Chromalveolates and the evolution of plastids by secondary endosymbiosis |journal=J. Eukaryot. Microbiol. |volume=56 |issue=1 |pages=1–8 |year=2009 |pmid=19335769 |doi=10.1111/j.1550-7408.2008.00371.x }}</ref> that became the progenitor of [[chlorophyll c]] containing [[plastid]]s. In a major classification produced in 2005, Chromalveolata was regarded as one of the six major groups within the eukaryotes.<ref name=Adl2005>
- {{cite
- | first = Sina M.
- | last = Adl
- | coauthors = ''et al.''
- | title = The New Higher Level Classification of Eukaryotes with Emphasis on the Taxonomy of Protists
- | journal = Journal of Eukaryotic Microbiology
- | year=2005 | volume=52 | issue=5 | pages=399
- | url=http://www.blackwell-synergy.com/doi/abs/10.1111/j.1550-7408.2005.00053.x
- | doi = 10.1111/j.1550-7408.2005.00053.x
-}}
-</ref>
-However the [[monophyly]] of the Chromalveolata has been increasingly challenged. Thus two papers published in 2008 have phylogenetic trees in which the chromalveolates are split up,<ref name=Burki2008a>{{Cite journal |last=Burki |first=Fabien |last2=Shalchian-Tabrizi |first2=Kamran |last3=Pawlowski |first3=Jan |year=2008 |title=Phylogenomics reveals a new 'megagroup' including most photosynthetic eukaryotes |journal=Biology Letters |volume=4 |pages=366–369 |doi=10.1098/rsbl.2008.0224 |lastauthoramp=yes |pmid=18522922 |issue=4 |pmc=2610160 |postscript=<!--None--> }}</ref><ref name=KimGraham2008>{{cite journal | doi = 10.1371/journal.pone.0002621 | year = 2008 | month = Jul | author = Kim, E; Graham, LE | editor1-last = Redfield | editor1-first = Rosemary Jeanne | title = EEF2 analysis challenges the monophyly of Archaeplastida and Chromalveolata. | volume = 3 | issue = 7 | pages = e2621 | pmid = 18612431 | pmc = 2440802 | journal = PLoS ONE | url = http://www.plosone.org/article/info:doi/10.1371/journal.pone.0002621 | format = Free full text |bibcode = 2008PLoSO...3.2621K }}</ref> and recent studies continue to support this view.<ref name=Burki2012/>
-==Groups and classification==
-[[Image:Kelp forest.jpg|thumb|A [[California]]n [[kelp forest]].]]
-Historically, many chromalveolates were considered [[plant]]s, because of their cell walls, photosynthetic ability, and in some cases their morphological resemblance to the land plants ([[Embryophyta]]). However, when the [[five-kingdom system]] took prevalence over the animal–plant dichotomy, most chromalveolates were put into the kingdom [[Protista]], with the [[water mold]]s and [[Labyrinthulomycetes|slime nets]] put into the kingdom [[Fungi]], and the [[brown algae]] staying in the plant kingdom.
-In 2005, in a classification reflecting the consensus at the time, the Chromalveolata were regarded as one of the six major [[clade]]s of eukaryotes.<ref name=Adl2005/> Although not given a formal taxonomic status in this classification, elsewhere the group has been treated as a Kingdom. The Chromalveolata were divided into four major subgroups:
-* [[Cryptophyta]]
-* [[Haptophyta]]
-* [[Heterokont|Stramenopiles]] (or Heterokontophyta)
-* [[Alveolata]]
-Other groups which may be included within, or related to, chromalveolates, are:
-*[[Centrohelid]]s
-*[[Katablepharid]]s
-*[[Telonemia]]<ref>{{cite journal | author = Shalchian-Tabrizi K, Eikrem W, Klaveness D, Vaulot D, Minge M, Le Gall F, Romari K, Throndsen J, Botnen A, Massana R, Thomsen H, Jakobsen K | title = Telonemia, a new protist phylum with affinity to chromist lineages | journal = Proc Biol Sci | volume = 273 | issue = 1595 | pages = 1833–42 | year = 2006 | pmid = 16790418 | pmc = 1634789 | doi = 10.1098/rspb.2006.3515}}</ref>
-Though several groups, such as the [[ciliate]]s and the [[water mold]]s, have lost the ability to photosynthesize, most are [[autotroph]]ic.  All photosynthetic chromalveolates use [[chlorophyll]]s ''a'' and ''c'', and many use accessory pigments. Chromalveolates share similar [[glyceraldehyde 3-phosphate dehydrogenase]] proteins.<ref name="pmid19270733">{{cite journal |author=Takishita K, Yamaguchi H, Maruyama T, Inagaki Y |editor1-last=Zhang |editor1-first=Baohong |title=A hypothesis for the evolution of nuclear-encoded, plastid-targeted glyceraldehyde-3-phosphate dehydrogenase genes in "chromalveolate" members |journal=PLoS ONE |volume=4 |issue=3 |pages=e4737 |year=2009 |pmid=19270733 |pmc=2649427 |doi=10.1371/journal.pone.0004737 |url=http://dx.plos.org/10.1371/journal.pone.0004737|bibcode = 2009PLoSO...4.4737T }}</ref>
-However, as early as 2005, doubts were being expressed as to whether the Chromalveolata was monophyletic,<ref>Harper, J. T., Waanders, E. & Keeling, P. J. 2005. On the monophyly of chromalveolates using a six-protein phylogeny of eukaryotes. Int. J. System. Evol. Microbiol., 55, 487-496. [http://www.botany.ubc.ca/keeling/PDF/05chromalvJSEM.pdf]</ref> and a review in 2006 noted the lack of evidence for several of the supposed six major eukaryote groups, including the Chromalveolata.<ref name="parfrey">{{cite journal | title = Evaluating Support for the Current Classification of Eukaryotic Diversity | author = Laura Wegener Parfrey, Erika Barbero, Elyse Lasser, Micah Dunthorn, Debashish Bhattacharya, David J Patterson, and Laura A Katz | doi = 10.1371/journal.pgen.0020220 | journal = PLoS Genet. | date = 2006 December | volume = 2 | issue = 12 | pages = e220 | pmid = 17194223 | pmc = 1713255 }}</ref> {{As of|2012}} there seems to be an emerging consensus that the group is not monophyletic. The four original subgroups fall into at least two categories: one comprises the Stramenopiles and the Alveolata, to which the [[Rhizaria]] are now usually added to form the [[SAR supergroup|SAR group]]; the other comprises the Cryptophyta and the Haptophyta.<ref name=Burki2008a/><ref name=KimGraham2008/> A 2010 paper splits the Cryptophyta and Haptophyta; the former are a sister group to the SAR group, the latter cluster with the [[Archaeplastida]] (plants in the broad sense).  The [[katablepharid]]s are closely related to the cryptophytes and the [[Telonemia|telonemid]]s and [[centrohelid]]s may be related to the haptophytes.<ref name=Burki2012>{{cite journal|last1=Burki |first1=F. |last2=Okamoto |first2=N. |last3=Pombert |first3= J.F. |last4=Keeling |first4=P.J. |year=2012 |title=The evolutionary history of haptophytes and cryptophytes: phylogenomic evidence for separate origins |journal=Proc. Biol. Sci. |doi=10.1098/rspb.2011.2301 |lastauthamp=yes}}</ref>
-A variety of names have been used for different combinations of the groups formerly thought to make up the Chromalveolata.
-* ''Halvaria'' Analyses in 2007 and 2008 agreed that the Stramenopiles and the Alveolata were related, forming a reduced chromalveolate clade, called [[Halvaria]].<ref name=Burki2007>{{cite journal|url=http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0000790|title=Phylogenomics Reshuffles the Eukaryotic Supergroups|author=Fabien Burki, Kamran Shalchian-Tabrizi, Marianne Minge, Åsmund Skjæveland, Sergey I. Nikolaev, Kjetill S. Jakobsen, Jan Pawlowski|journal=PLoS ONE|volume=2|issue=8|doi=10.1371/journal.pone.0000790|year=2007|pages=e790|pmid=17726520|pmc=1949142|bibcode = 2007PLoSO...2..790B }}</ref><ref name=Burki2008a>{{Cite journal |last=Burki |first=Fabien |last2=Shalchian-Tabrizi |first2=Kamran |last3=Pawlowski |first3=Jan |year=2008 |title=Phylogenomics reveals a new 'megagroup' including most photosynthetic eukaryotes |journal=Biology Letters |volume=4 |pages=366–369 |doi=10.1098/rsbl.2008.0224 |lastauthoramp=yes |pmid=18522922 |issue=4 |pmc=2610160 |postscript=<!--None--> }}</ref><ref name=KimGraham2008>{{cite journal | doi = 10.1371/journal.pone.0002621 | year = 2008 | month = Jul | author = Kim, E; Graham, LE | title = EEF2 analysis challenges the monophyly of Archaeplastida and Chromalveolata. | volume = 3 | issue = 7 | pages = e2621 | pmid = 18612431 | pmc = 2440802 | journal = PLoS ONE | url = http://www.plosone.org/article/info:doi/10.1371/journal.pone.0002621 | format = Free full text |bibcode = 2008PLoSO...3.2621K }}</ref>
-* ''SAR group'' The Rhizaria, which were originally not considered to be chromalveolates, belong with the Stramenopiles and Alveolata in many analyses, forming the [[SAR supergroup|SAR group]], i.e. the Halvaria plus the Rhizaria.<ref name=Burki2007/><ref name="pmid19237557">{{cite journal |author=Hampl V, Hug L, Leigh JW, ''et al'' |title=Phylogenomic analyses support the monophyly of Excavata and resolve relationships among eukaryotic "supergroups" |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=106 |issue=10 |pages=3859–64 |year=2009 |month=March |pmid=19237557 |doi=10.1073/pnas.0807880106 |url=http://www.pnas.org/cgi/pmidlookup?view=long&pmid=19237557 |pmc=2656170 |bibcode=2009PNAS..106.3859H}}</ref>
-* ''Hacrobia'' The other two groups originally included in Chromalveolata, the Haptophyta and the Cryptophyta, were related in some analyses,<ref name=Burki2008a/><ref name=KimGraham2008/> forming a clade which has been called [[Hacrobia]]. Alternatively, the Hacrobia appeared to be more closely related to the [[Archaeplastida]] (plants in the very broad sense), being a sister group in one analysis,<ref name=Burki2008a/> and actually nested inside this group in another.<ref name=KimGraham2008/> (Earlier, [[Cavalier-Smith]] had suggested a clade called [[Corticata]] for the grouping of ''all'' the chromalveolates and the Archaeplastida.) More recently, as noted above, the Hacrobia has been split, with the Haptophyta being sister to the SAR group and the Cryptophyta instead related to the Archaeplastida.<ref name=Burki2012/>
-{{See also|Eukaryote#Phylogeny}}
-==Morphology==
-Chromalveolates, unlike other groups with multicellular representatives, do not have very many common morphological characteristics.  Each major subgroup has certain unique features, including the alveoli of the Alveolata, the haptonema of the Haptophyta, the ejectisome of the Crytophyta, and the two different flagella of the Heterokontophyta.  However, none of these features are present in all of the groups.
-The only common chromalveolate features are these:
-*The shared origin of chloroplasts, as mentioned above
-*Presence of [[cellulose]] in most cell walls
-Since this is such a diverse group, it is difficult to summarize shared chromalveolate characteristics.
-==Ecological role==
-[[Image:symptom potato late blight.jpg|right|thumb|A potato plant infected with ''[[Phytophthora infestans]]''.]]
-Many chromalveolates affect our ecosystem in enormous ways.  Some of these organisms can be very harmful.  [[Dinoflagellate]]s produce [[red tide]]s which can devastate fish populations and intoxicate oyster harvests.  [[Apicomplexan]]s are some of the most successful specific parasites to animals.  Water molds cause several plant diseases.  In fact, it was a water mold, ''[[Phytophthora infestans]]'', that caused the [[Great Irish Famine|Irish potato famine]].
-However, many chromalveolates are vital members of our ecosystem.  [[Diatom]]s are one of the major photosynthetic producers, and as such produce much of the [[oxygen]] we breathe, and also take in much of the [[carbon dioxide]] from the atmosphere.  [[Brown algae]], most specifically [[kelp]]s, create underwater "forest" habitats for many marine creatures, and provide a large portion of the diet of coastal communities.
-Chromalveolates also provide many products that we use.  The [[algin]] in brown algae is used as a food thickener, most famously in [[ice cream]].  The siliceous shells of diatoms have many uses, such as in reflective paint, in toothpaste, or as a filter, in what is known as [[diatomaceous earth]].
-{{-}}
-==References==
-{{reflist|2}}
-==External links==
-* [http://tolweb.org/Eukaryotes/3 Tree of Life Eukaryotes]
-{{Life}}
-{{Heterokont}}
-{{Alveolata}}
-{{Cryptophyta and haptophyta}}
-[[Category:Chromalveolata| ]]
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