Phylum Cnidaria (Jelly Fish)
Cnidarians are soft-bodied, carnivorous animals that have stinging tentacles arranged around the mouth. They are the simplest animals to have body symmetry and specialized tissues.
Body Plan:
Cnidarians are radially symmetrical. They have tentacles that surround the mouth. They have a life cycle hat includes two stages: Polyp an Medusa. (shown on right) Feeding:
After paralyzing its prey, it pulls it through its mouth into its gastrovascular cavity. Partially digested food is absorbed by the gastrodern. Any materials that cannot be digested are passed out of the body through the mouth.
Response:
Cnidarians gather information from specialized sensory cells. A nerve net is a loose organized network of nerve cells that detect stimuli. Statocysts are groups of sensory cells that determine direction of gravity. Ocelli are eyespots made to detect light. Classes of Cndiarians
Scyhozoa (Jelly Fish) -Primarily are medusas -Reproduce sexually Hydrozoa (Hydras & Relatives) -Grow in branching colonies -Within colony, polyps are specialized to preform different functions -Don't have medusa stage Anthozoa (Sea anemones & Corals) -Only have polyp stage -Central body with tentacles -Reproduce by budding most of the time -They have an underlying skeleton of calcium carbonate or limestone. |
Respiration, Circulation, and Excretion:
Nutrients are transported throughout the body by diffusion. Cnidarians respire and eliminate the wastes of cellular metabolism by diffusion through their body walls. Reproduction:
Cnidarians reproduce both sexually and asexually. How Jelly Fish sting: http://www.youtube.com/watch?v=-Tp38DUjUnM
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