Jellyfish Essay

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The class Scyphozoa has about 200 species of jellies, with a wide distribution. “True Jellyfish” have a diverse range of habitats; we can find them in salty estuaries, bays; the pelagic zone of the ocean and the abyssal depths of the ocean. Pelagic Cnidarians are found in the pelagic zone of the ocean. The term “Pelagic” literally defines to, open ocean. Scyphozoan jellyfish are keystone species, being a primary and important predator within their marine ecosystems. They have been a key species in their ecosystems throughout the Phanerozoic Period and also since the middle of the Cambrian Period, which is when fossils of major animal groups first appeared. (Hagadorn et al. 2002; Cartwright et al. 2007; Hagadorn and Belt 2008 cited by Dawson) An ancient origin of the aggregated phenomenon of scyphomedusae as been retrieved from marine fossil deposits dating back to the late Cambrian period Hagadorn et al. 2002 cited by Dawson). Scyphozoans have become more commonly criticized as an ”annoying” species, forming countless problems worldwide. Aggregations and swarms of Scyphozoan jellyfish can negatively affect important aquacultures and injure swimming bystanders. (Reword******They are also known as an invasive species clogging the water intakes of power plants, due to the high concentration of nitrate located in the waters surrounding the plant, thus adversely impacting the human lifestyle further (reword). On top of it, jellyfish also trigger poor oxygen conditions within certain waters where synchronously is the same areas that contain high counts of jellyfish carcasses are deposited***** Reword) (Arai 1997; Mills 2001; Hay 2006; Graham and Bayha 2007; Purcell et al. 2007; Pitt et al. 2009; Richardson et al. 2009; West et al. 2...

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...d by Dawson), regarding the more isolated family, Lychnorhizidae, alternative to the recent taxonomic behavior, which includes three distinct families (Kramp 1961 cited by Dawson). The final and fifth way it conflicts is through the family, Nausithoidae. This family is paraphyletic and/or polyphyletic (Figs. 3-5). Even with the debatable oppositions and relationships within the coronates, the phylogenetic locations of tropical shallow water, Nausithoe sp. and genetically outlying deep water species, Nausithoe atlantica and Nausithoe rubra collectively landmark Nausithoidae as a non-monophyletic. Also, the identification of Atorella as a nausithoid (Mills et al. 1987 cited by Dawson) isolates Nausithoidae as a non-monophyletic, which allowed them to interpret their trees as supporting recognition of Family Atorellidae (Eggers and Jarms 2007 cited by Dawson).

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