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