2Cnidarians Jellies, Anemones, Corals Dimorphism: Two body shapes during life cycle. (Polyp & Medusa)Gastrovascular cavity (digestive)CarnivoresPrimitive nerve netTwo distinct tissue layers: Epidermis & GastrodermisCnidocyte (Stinging cells) in tentaclesRadial Symmetry
3 The Polyp and Medusa Stages EpidermisMesogleaGastrodermTentaclesMouth/anusGastrovascular cavityMesogleaGastrovascular cavityMouth/anusTentaclesPolypMedusa
4Feeding Paralyze prey and pulls into mouthgastrovascular cavity Undigested materials passed out through mouth/anus
5Respiration, Circulation, Excretion Diffusion through body wallsNerve net-network of nerve cells to detect stimuliStatocysts to determine gravity directionOcelli as eyespots to detect lightResponse
6Movement Hydrostatic skeleton-muscles w/ water enable movement Body contracts to force water out, moving jellyfish in opposite direction.
7Reproduction and Life cycle Most cnidarians reproduce both sexually and asexually.External fertilization
8Jellyfish Life Cycle Female medusa (2N) MEIOSISFertilization occurs in the open water, producing many diploid zygotes.Egg (N)Adult medusas reproduce sexually by releasing gametes into the water.FERTILIZATIONSperm (N)Each zygote grows into a ciliated larva. The larva eventually attaches to a hard surface and develops into a polyp.Zygote (2N)Male medusa (2N)Young medusaSwimming larvaPolypThe polyp buds to release young medusas.HaploidDiploidBudding polyp