Red algae

Red algae
Temporal range: Mesoproterozoic–present[1][2]
A-D : Chondrus crispus Stackhouse,
E-F : Mastocarpus stellatus J.Ag.
Scientific classification Edit this classification
Domain: Eukaryota
Clade: Diaphoretickes
(unranked): Archaeplastida
Division: Rhodophyta
Wettstein, 1922
Clades

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 centrioles. Their chloroplasts lack external endoplasmic reticulum. These chloroplasts have unstacked (stroma) thylakoids.

Phycobiliproteins are accessory pigments, which give them their red color.[3] 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.[4]

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.[5]

Chloroplasts evolved following an endosymbiotic event between an ancestral, photosynthetic cyanobacterium and an early eukarytoic phagotroph.[6]

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

  1. ↑ N. J. Butterfield (2000). "Bangiomorpha pubescens n. gen., n. sp.: implications for the evolution of sex, multicellularity, and the Mesoproterozoic/Neoproterozoic radiation of eukaryotes". Paleobiology. 26 (3): 386–404. doi:10.1666/0094-8373(2000)026<0386:BPNGNS>2.0.CO;2. ISSN 0094-8373. S2CID 36648568.
  2. ↑ T.M. Gibson (2018). "Precise age of Bangiomorpha pubescens dates the origin of eukaryotic photosynthesis". Geology. 46 (2): 135–138. Bibcode:2018Geo....46..135G. doi:10.1130/G39829.1.
  3. ↑ W. J. Woelkerling (1990). "An introduction". In K. M. Cole; R G. Sheath (eds.). Biology of the Red Algae. Cambridge University Press, Cambridge. pp. 1–6. ISBN 978-0-521-34301-5.
  4. ↑ Viola, R.; Nyvall, P.; Pedersén, M. (2001). "The unique features of starch metabolism in red algae". Proceedings of the Royal Society of London B. 268 (1474): 1417–1422. doi:10.1098/rspb.2001.1644. PMC 1088757. PMID 11429143.
  5. ↑ "Algae". autocww.colorado.edu. Archived from the original on 2012-03-15. Retrieved 2019-07-20.
  6. ↑ Gould, S.B.; Waller, R.F.; McFadden, G.I. (2008). "Plastid Evolution". Annual Review of Plant Biology. 59: 491–517. doi:10.1146/annurev.arplant.59.032607.092915. PMID 18315522.