View source for Red algae

{{Automatic taxobox
| name = Red algae
| fossil_range = {{long fossil range|Mesoproterozoic|present|ref=<ref name="butterfield">{{cite journal |author=N. J. Butterfield |year=2000 |title=''Bangiomorpha pubescens'' n. gen., n. sp.: implications for the evolution of sex, multicellularity, and the Mesoproterozoic/Neoproterozoic radiation of eukaryotes |journal=[[Paleobiology (journal)|Paleobiology]] |volume=26 |issue=3 |pages=386–404 |url=http://paleobiol.geoscienceworld.org/cgi/content/abstract/26/3/386 |doi=10.1666/0094-8373(2000)026<0386:BPNGNS>2.0.CO;2 |s2cid=36648568 |issn=0094-8373}}</ref><ref name=Gibson>{{cite journal | author = T.M. Gibson | year = 2018 | title = Precise age of Bangiomorpha pubescens dates the origin of eukaryotic photosynthesis | url = https://pubs.geoscienceworld.org/gsa/geology/article/46/2/135/524864/Precise-age-of-Bangiomorpha-pubescens-dates-the | journal = [[Geology (journal)|Geology]] | volume = 46 | issue = 2 | pages = 135–138 | doi = 10.1130/G39829.1 | bibcode = 2018Geo....46..135G }}</ref>}}
| image = Chondrus_crispus_-_Köhler–s_Medizinal-Pflanzen-034.jpg 
| image_caption = A-D : ''[[Chondrus crispus]]'' [[John Stackhouse (botanist)|Stackhouse]], <br />E-F : ''[[Mastocarpus stellatus]]'' [[J.Ag.]]
| image_upright = 1.15
| display_parents = 3
| taxon = Rhodophyta
| authority = [[Richard Wettstein|Wettstein]], 1922
| subdivision_ranks = Clades
| subdivision = 
*[[Eurhodophytina]]
**[[Bangiophyceae]]
**[[Florideophyceae]]
*[[Proteorhodophytina]]
**[[Compsopogonophyceae]]
**[[Porphyridiophyceae]]
**[[Rhodellophyceae]]
**[[Stylonematophyceae]]
*[[Cyanidiophytina]]
**[[Cyanidiophyceae]]
}}

'''Red algae''' are members of the phylum '''Rhodophyta'''. This is a large group of aquatic [[algae]] with about 6000 species. They have reddish [[phycobilin]] pigments—[[phycoerythrin]] and [[phycocyanin]]. 

The red algae are a distinct group. They have eukaryotic cells without [[flagella]] and [[centriole]]s. Their [[chloroplasts]]  lack external [[endoplasmic reticulum]]. These chloroplasts have unstacked (stroma) [[thylakoid]]s. 

Phycobiliproteins are accessory [[pigments]], which give them their red color.<ref name="Woelkerling 90">{{cite book|title=Biology of the Red Algae|url=https://archive.org/details/biologyofredalga0000unse|publisher=Cambridge University Press, Cambridge|year=1990|isbn=978-0-521-34301-5|pages=[https://archive.org/details/biologyofredalga0000unse/page/1 1]–6|chapter=An introduction|author=W. J. Woelkerling|editor1=K. M. Cole|editor2=R G. Sheath}}</ref> What these pigments do is the same as what [[chlorophyll]] does: absorb sunlight as energy, which is then used to fuel the building of organic compounds.

Red algae store [[sugars]] as a type of [[starch]]  outside their plastids.<ref name=Viola>{{cite journal|last1=Viola|first1=R.|last2=Nyvall|first2=P.|last3=Pedersén|first3=M.|year=2001|title=The unique features of starch metabolism in red algae|journal=Proceedings of the Royal Society of London B|volume=268|issue=1474|pages=1417–1422|doi=10.1098/rspb.2001.1644|pmid=11429143|pmc=1088757}}</ref> 

Most red algae are multicellular, macroscopic, marine, and reproduce sexually. The usual red algal life history is an [[alternation of generations]] with three generations rather than two.<ref>{{cite web|url=http://autocww.colorado.edu/~toldy2/E64ContentFiles/AlgaeAndFungi/Algae.html|title=Algae|publisher=autocww.colorado.edu|access-date=2019-07-20|archive-date=2012-03-15|archive-url=https://web.archive.org/web/20120315030820/http://autocww.colorado.edu/~toldy2/E64ContentFiles/AlgaeAndFungi/Algae.html|url-status=dead}}</ref>

Chloroplasts evolved following an [[endosymbiosis|endosymbiotic]] event between an ancestral, photosynthetic [[cyanobacterium]] and an early eukarytoic [[phagocyte|phagotroph]].<ref>{{Cite journal|last1=Gould|first1=S.B.|last2=Waller|first2=R.F.|last3=McFadden|first3=G.I.|year=2008|title=Plastid Evolution|url=https://archive.org/details/sim_annual-review-of-plant-biology_2008_59/page/491|journal=Annual Review of Plant Biology|volume=59|pages=491–517|doi=10.1146/annurev.arplant.59.032607.092915|pmid=18315522}}</ref>

Most species grow near tropical and subtropical shores below the low-tide mark. A few are found in [[fresh water]]. Red algae is used to make the food ''[[Nori]]''.

== References ==
{{reflist}}


[[Category:Algae]]