Coelenterata is a term encompassing the animal phylaCnidaria (coral animals, true jellies, sea anemones, sea pens, and their relatives) and Ctenophora (comb jellies). The name comes from Ancient Greekκοῖλος (koîlos) 'hollow', and ἔντερον (énteron) 'intestine', referring to the hollow body cavity common to these two phyla.[1][2] They have very simple tissue organization, with only two layers of cells (ectoderm and endoderm), and radial symmetry. Some examples are corals, which are typically colonial, and hydrae, jellyfish, and sea anemones, which are solitary. Coelenterata lack a specialized circulatory system relying instead on diffusion across the tissue layers.
All coelenterates are aquatic, mostly marine, animals. The body form is radially symmetrical, diploblastic and does not have a coelom. The body has a single opening, the hypostome, surrounded by sensory tentacles equipped with either nematocysts or colloblasts to capture mostly planktonic prey. These tentacles are surrounded by a spacious cavity called the gastrovascular cavity, or coelenteron. Digestion is both intracellular and extracellular. Respiration and excretion are accomplished by simple diffusion. A network of nerves is spread throughout the body. Many Cnidaria exhibit polymorphism, wherein different types of individuals are present in a colony for different functions. These individuals are called zooids. These animals generally reproduce asexually by budding, though sexual reproduction does occur in some groups.
History of classificationedit
The scientific validity of the term coelenterate is currently rejected, as the Cnidaria and Ctenophora have less in common than previously assumed.[3] Coelentera may only be monophyletic if both Placozoa and Bilateria are included.[4] In particular, the phylogenetic position of Ctenophora is controversial; it was first considered a sub-group of coelenterata but Hyman regarded it as a separate phylum.[4][5] Most researchers think that Coelenterata is not monophyletic, and therefore any group containing Cnidaria and Ctenophora but excluding other phyla would be paraphyletic.
Previously, some genomic studies have found support for monophyletic coelenterates.[6][7] Despite this uncertainty, the term coelenterate is still used in informal settings to refer to the Cnidaria and Ctenophora.
Complicating the issue is the 1997 work of Lynn Margulis (revising an earlier model by Thomas Cavalier-Smith) that placed the Cnidaria and Ctenophora alone in the branch Radiata within Eumetazoa.[8] (The latter refers to all the animals except the sponges, Trichoplax, and the still poorly understood Mesozoa). Neither grouping is accepted universally,[9] however, both are commonly encountered in taxonomic literature.[3][6]
^ abDunn, Casey W.; Leys, Sally P.; Haddock, Steven H.D. (May 2015). "The hidden biology of sponges and ctenophores". Trends in Ecology & Evolution. 30 (5): 282–291. doi:10.1016/j.tree.2015.03.003. PMID 25840473.
^ abPisani, Davide; Pett, Walker; Dohrmann, Martin; Feuda, Roberto; Rota-Stabelli, Omar; Philippe, Hervé; Lartillot, Nicolas; Wörheide, Gert (2015-12-15). "Genomic data do not support comb jellies as the sister group to all other animals". Proceedings of the National Academy of Sciences. 112 (50): 15402–15407. Bibcode:2015PNAS..11215402P. doi:10.1073/pnas.1518127112. ISSN 0027-8424. PMC4687580. PMID 26621703.
^Whelan, Nathan V.; Kocot, Kevin M.; Moroz, Leonid L.; Halanych, Kenneth M. (2015-05-05). "Error, signal, and the placement of Ctenophora sister to all other animals". Proceedings of the National Academy of Sciences. 112 (18): 5773–5778. Bibcode:2015PNAS..112.5773W. doi:10.1073/pnas.1503453112. ISSN 0027-8424. PMC4426464. PMID 25902535.
^ abPhilippe, Hervé; Derelle, Romain; Lopez, Philippe; Pick, Kerstin; Borchiellini, Carole; Boury-Esnault, Nicole; Vacelet, Jean; Renard, Emmanuelle; Houliston, Evelyn (April 2009). "Phylogenomics Revives Traditional Views on Deep Animal Relationships". Current Biology. 19 (8): 706–712. doi:10.1016/j.cub.2009.02.052. ISSN 0960-9822. PMID 19345102.
^Nosenko, Tetyana; Schreiber, Fabian; Adamska, Maja; Adamski, Marcin; Eitel, Michael; Hammel, Jörg; Maldonado, Manuel; Müller, Werner E. G.; Nickel, Michael (2013-04-01). "Deep metazoan phylogeny: When different genes tell different stories". Molecular Phylogenetics and Evolution. 67 (1): 223–233. doi:10.1016/j.ympev.2013.01.010. PMID 23353073.
^Margulis, Lynn and Karlene V. Schwartz, 1997, Five Kingdoms: An Illustrated Guide to the Phyla of Life on Earth, W.H. Freeman & Company, ISBN0-613-92338-3
coelenterata, term, encompassing, animal, phyla, cnidaria, coral, animals, true, jellies, anemones, pens, their, relatives, ctenophora, comb, jellies, name, comes, from, ancient, greek, κοῖλος, koîlos, hollow, ἔντερον, énteron, intestine, referring, hollow, bo. Coelenterata is a term encompassing the animal phyla Cnidaria coral animals true jellies sea anemones sea pens and their relatives and Ctenophora comb jellies The name comes from Ancient Greek koῖlos koilos hollow and ἔnteron enteron intestine referring to the hollow body cavity common to these two phyla 1 2 They have very simple tissue organization with only two layers of cells ectoderm and endoderm and radial symmetry Some examples are corals which are typically colonial and hydrae jellyfish and sea anemones which are solitary Coelenterata lack a specialized circulatory system relying instead on diffusion across the tissue layers CoelenteratesComb jellies Beroe spp Scientific classificationKingdom AnimaliaSubkingdom EumetazoaPhylum CoelenterataHatschek 1888PhylaCtenophora CnidariaCharacteristics editAll coelenterates are aquatic mostly marine animals The body form is radially symmetrical diploblastic and does not have a coelom The body has a single opening the hypostome surrounded by sensory tentacles equipped with either nematocysts or colloblasts to capture mostly planktonic prey These tentacles are surrounded by a spacious cavity called the gastrovascular cavity or coelenteron Digestion is both intracellular and extracellular Respiration and excretion are accomplished by simple diffusion A network of nerves is spread throughout the body Many Cnidaria exhibit polymorphism wherein different types of individuals are present in a colony for different functions These individuals are called zooids These animals generally reproduce asexually by budding though sexual reproduction does occur in some groups History of classification editThe scientific validity of the term coelenterate is currently rejected as the Cnidaria and Ctenophora have less in common than previously assumed 3 Coelentera may only be monophyletic if both Placozoa and Bilateria are included 4 In particular the phylogenetic position of Ctenophora is controversial it was first considered a sub group of coelenterata but Hyman regarded it as a separate phylum 4 5 Most researchers think that Coelenterata is not monophyletic and therefore any group containing Cnidaria and Ctenophora but excluding other phyla would be paraphyletic Previously some genomic studies have found support for monophyletic coelenterates 6 7 Despite this uncertainty the term coelenterate is still used in informal settings to refer to the Cnidaria and Ctenophora Complicating the issue is the 1997 work of Lynn Margulis revising an earlier model by Thomas Cavalier Smith that placed the Cnidaria and Ctenophora alone in the branch Radiata within Eumetazoa 8 The latter refers to all the animals except the sponges Trichoplax and the still poorly understood Mesozoa Neither grouping is accepted universally 9 however both are commonly encountered in taxonomic literature 3 6 References edit coelenterate Lexico UK English Dictionary Oxford University Press Archived from the original on 2020 08 05 coelenterate Merriam Webster com Dictionary Retrieved 2017 02 25 a b Dunn Casey W Leys Sally P Haddock Steven H D May 2015 The hidden biology of sponges and ctenophores Trends in Ecology amp Evolution 30 5 282 291 doi 10 1016 j tree 2015 03 003 PMID 25840473 a b Pisani Davide Pett Walker Dohrmann Martin Feuda Roberto Rota Stabelli Omar Philippe Herve Lartillot Nicolas Worheide Gert 2015 12 15 Genomic data do not support comb jellies as the sister group to all other animals Proceedings of the National Academy of Sciences 112 50 15402 15407 Bibcode 2015PNAS 11215402P doi 10 1073 pnas 1518127112 ISSN 0027 8424 PMC 4687580 PMID 26621703 Whelan Nathan V Kocot Kevin M Moroz Leonid L Halanych Kenneth M 2015 05 05 Error signal and the placement of Ctenophora sister to all other animals Proceedings of the National Academy of Sciences 112 18 5773 5778 Bibcode 2015PNAS 112 5773W doi 10 1073 pnas 1503453112 ISSN 0027 8424 PMC 4426464 PMID 25902535 a b Philippe Herve Derelle Romain Lopez Philippe Pick Kerstin Borchiellini Carole Boury Esnault Nicole Vacelet Jean Renard Emmanuelle Houliston Evelyn April 2009 Phylogenomics Revives Traditional Views on Deep Animal Relationships Current Biology 19 8 706 712 doi 10 1016 j cub 2009 02 052 ISSN 0960 9822 PMID 19345102 Nosenko Tetyana Schreiber Fabian Adamska Maja Adamski Marcin Eitel Michael Hammel Jorg Maldonado Manuel Muller Werner E G Nickel Michael 2013 04 01 Deep metazoan phylogeny When different genes tell different stories Molecular Phylogenetics and Evolution 67 1 223 233 doi 10 1016 j ympev 2013 01 010 PMID 23353073 Margulis Lynn and Karlene V Schwartz 1997 Five Kingdoms An Illustrated Guide to the Phyla of Life on Earth W H Freeman amp Company ISBN 0 613 92338 3 Taxonomy browser Eumetazoa www ncbi nlm nih gov Retrieved from https en wikipedia org w index php title Coelenterata amp oldid 1108289583, wikipedia, wiki, book, books, library,
