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Phylum Porifera Essay Example

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Phylum Porifera

Most of the sponge species feed on the food particles or bacteria in the water, where some of them host micro organisms for photosynthesizing processes to act as endosymbionts. Such associations ensure there is maximum production of oxygen and food in the water, as compared to what they consume. However, some sponges that live in environment with small or no food have become carnivores since they mainly prey on crustaceans or other living organisms.Majority of individual animals in this phylum Polifera are believed to be radically symmetrical. Furthermore, sponges are made up of layers of cells, three layers with the outer layer consisting of flattened cells that have numerous pores. This layer contains cells that are mobile and skeletal cells that result into the shape of the sponge. The innermost layer is made up of predominantly choanocytes. The choanocytes are made up of rings which surround the base of the flagella. The flagella’s main function is the facilitation of propelling of water via the pores to the body i. in the body central cavity.The phylum Polifera is classified into three distinct groups. This are the Hexactinellida, also referred to as the glass sponges, Calcarea, also referred to as calcareous sponges, and the Demospongia. In previous phylogenetic studies carried out by various researchers indicated that sponges are monophyletic. Recently, there has arisen several hypothesis that suggest that phylum Polifera is a paraphyletic rather than monophyletic. As it has been connoted above, phylum Polifera has been known to be monophyletic that exists within the metazoan. This is supported by various proofs ranging from the biphasic life cycle, choanocytes, filter feeding habits, aquiferous system, Pinacocytes, and choanocytes.The first phylamic activity in the investigation of higher sponge was done in the year 1992. The investigation was with molecular sequence data. This process involved the use of approximately 400 bp of 28S rDNA. In the analysis of the project, it was suggested that that sponges are Paraphyletic in Nature. Also, during the investigation, paraphyletic demosponges were found.In another different experiment carried out by Wachter and Van De Peer, in which the RNA secondary structure was used for guidance in the alignment of the 18S rDNA, approximately five hundred eukaryotic

Works Cited

Collins, A.G. 1998. Evaluating multiple alternative hypotheses for the origin of bilateria: an analysis of 18S rRNA molecular evidence. Proc. Nat. Acad. Sci. USA 95: 15458-15463.

Dewel, R.A. 2000. Colonial origin for Eumetazoa: major morphological transitions and the origin of bilaterian complexity. J. Morph. 243: 35-74.

eukaryotic kingdoms. J. Mol. Evol. 42: 183-193.

Kruse, M., Leys, S.P., MuÈ ller, I.M. & MuÈ ller, W.E.G. 1998. Phylogenetic position of the Hexactinellida within the phylum Porifera based on the amino acid sequence of the protein kinase C from Rhabdocalyptus dawsoni. J. Mol. Evol. 46: 721-728.

Kumar, S. & Rzhetsky, A. 1996. Evolutionary relationships of

Murphy, Richard C. (2002). Coral Reefs: Cities Under The Seas. The Darwin Press, Inc. p. 51. ISBN 0-87850-138-X.

Watkins, R.F. & Beckenbach, A.T. 1999. Partial sequence of a sponge mitochondrial genome reveals sequence similarity to Cnidaria in cytochrome oxidase subunit II and the large ribosomal RNA subunit. J. Mol. Evol. 48: 542-554.

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preview essay on Phylum Porifera
  • Pages: 5 (1250 words)
  • Document Type: Essay
  • Subject: Biology
  • Level: Undergraduate
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