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Phylum Cnidaria. Hydra, jellyfish, coral, & sea anemones. Phylum Cnidaria. Examples? Sea anemones Corals Sea Pen Sea Fan Sea Plume Hydra Jelly fish Portuguese Man o’ War Box Jelly Fish. I. Body Structure. A. Polymorphism = more than one body form 1. Polyp 2. Medusa.
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Phylum Cnidaria Hydra, jellyfish, coral, & sea anemones
Phylum Cnidaria Examples? • Sea anemones • Corals • Sea Pen • Sea Fan • Sea Plume • Hydra • Jelly fish • Portuguese Man o’ War • Box Jelly Fish
I. Body Structure A. Polymorphism = more than one body form 1. Polyp 2. Medusa
B. Polyp • Tube with tentacles around the mouth • Sessile Coral polyp
C. Medusa • Umbrella shape • Tentacles around mouth • Motile, Free-swimming
D. Tentacles • Have nematocysts (stinging cells) • Coiled thread discharges like a harpoon • Contains neurotoxin • Paralyzes prey Discharged nematocyst
II. Level of Organization A. Tissue B. No organs
III. Symmetry Radial Compass jellyfish
IV. Habitat A. Aquatic 1. Most Marine 2. Few fresh-water
V. Feeding A. Carnivores (predators) B. Process of feeding 1. Tentacles sting prey with nematocysts 2. Tentacles grab prey 3. Prey pulled into mouth Lion’s mane eats another jelly
Process of feeding 4. Prey stuffed into gastro-vascular cavity (GVC)* 5. GVC makes enzymes, extra-cellular digestion 6. Undigested food back out mouth *incomplete digestive tract (no anus)
VI. Respiration • Via diffusion • Body is two cell layers thick
VII. Internal Transport Via diffusion
VIII. Excretion • Via diffusion
IX. Response • No cephalization or nervous system • Nerve net around mouth
IX. Response C. Sensory cells 1. Chemoreceptors (chemicals) 2. Thigmoreceptors (touch) 3. Photoreceptors (light) Ocelli (eyespots) 4. Statocysts (balance)
X. Locomotion • Medusa motile, free-swimming • Polyps sessile Exceptions: 1. Hydra tumbles on tentacles 2. Sea anemones glide on pedal disc
XI. Reproduction 1. Asexual budding from polyps or medusae 2. Sexual a. Medusae release sperm & eggs b. Some monoecious, some dioecious c. Larvae free-swimming
XII. Ecological Role • Predators and prey • Neurotoxins in medical research • Coral – jewelry, building, reefs (surfing!) • Coral reefs - habitat for many -great biodiversity - protect coastline E. Symbiosis with other organisms