BIO 2129 Final: Final_Exam_-_Cnidarians.doc
1 Dec 2014
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Document Summary
Jellyfish, corals, sea anemones, and hydroids are members of the phylum. Cnidarians are either solitary, or form huge colonies and are carnivores that sting: flatworms and molluscs have literally stolen the cnidarian defensive strategy. There is a layer of mesoglea or mesenchyme between the layers: organized at the metabolic wall. wastes is accomplished by diffusion across the body, asexual reproduction, which can occur in polyps and some medusa, includes budding and fragmentation. Cnidarians are dioecious; gonads may form from the epidermis or gastrodermis, and male and female medusae release their gametes into the surrounding water. In some species, the female broods the developing embryos. One of the most distinctive features of the cnidaria is their radial symmetry, and it gives us some clues to how they function. Absence of directed movement: nerve net distributed throughout the body as nervous system, sensory structures are evenly spaced around the whole organism allowing it to react equally well in all directions.
