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Phylum Cnidaria Hydra, jellyfish, coral, & sea anemones Phylum Cnidaria Examples? CHARACTERISTICS • Sea anemones • digestive cavity with no anus • Corals • tentacles with nematocysts (toxic • Sea Pen cells to trap prey) • Sea Fan • thick mesoglea, shallow marine • Sea Plume • Hydra • Jelly fish • Portuguese Man o’ War • Box Jelly Fish Body Structure Polymorphism = more than one body form 1. Polyp 2. Medusa Polyp • Tube with tentacles around the mouth • Sessile Coral polyp Polyp (sea anemone) Polyp (Hydra) Medusa • Umbrella shape • Tentacles around mouth • Motile, Free-swimming • Have nematocysts (stinging cells) • Coiled thread discharges like a harpoon • Contains neurotoxin • Paralyzes prey Tentacles Discharged nematocyst Discharged nematocyst Level of Organization Tissue No organs Symmetry Radial Compass jellyfish Habitat Aquatic Most Marine Few fresh-water Feeding Carnivores (predators) Process of feeding Lion’s mane eats another jelly – Tentacles sting prey with nematocysts – Tentacles grab prey – Prey pulled into mouth Process of feeding • Prey stuffed into gastro-vascular • • cavity (GVC)* GVC makes enzymes, extracellular digestion Undigested food back out mouth *incomplete digestive tract (no anus) Lion’s mane jellyfish eating Respiration • Via diffusion • Body is two cell layers thick Internal Transport Via diffusion Excretion • Via diffusion Response • No cephalization or nervous system • Nerve net around mouth Response Sensory cells • Chemoreceptors (chemicals) • Thigmoreceptors (touch) • Photoreceptors (light) – Ocelli (eyespots) • Statocysts (balance) Locomotion • Medusa motile, free-swimming • Polyps sessile Exceptions: • Hydra tumbles on tentacles • Sea anemones glide on pedal disc Reproduction • Asexual budding from polyps or medusae • Sexual • Medusae release sperm & eggs • Some monoecious, some dioecious • Larvae free-swimming Ecological Role • • • • Predators and prey Neurotoxins in medical research Coral – jewelry, building, reefs (surfing!) Coral reefs - habitat for many • great biodiversity • protect coastline • Symbiosis with other organisms Class Anthozoa: Sea Anemones ~thick polyp, no medusa stage Sea Anemones (with sea urchins) Sea Anemones Clown fish with sea anemone Clown fish & eggs with sea anemone Clown fish with sea anemone Giant Sea Anemone Rosy Sea Anemone Class Anthozoa: Corals ~small polyps secrete calcium cup Brain Coral C O R A L Colt Coral Elkhorn Coral Cabbage Coral Flower Coral Feather Coral Gorgonian Fan Coral Lamellina Coral Sun Coral Subergorgia Coral Soft Coral Sea Pen S e a F a n Sea Plume Class Hydrozoa: - colony of polyps or small medusa (round gonads) - Portuguese Man-of-war (gas-filled float) Green Hydra Hydra Brown Hydra with buds Brown Hydra eating Hydra eating Daphnia • Hydra eats Daphnia Class Scyphozoa: True Jellyfish - polyps during larval stage - large medusa in adults Fried egg jelly Jellyfish Jellyfish Red-eyed medusa Jellyfish Jellyfish Jellyfish Lion’s mane Jellyfish Purple lion’s mane Upside down Jelly fish Upside down Jelly fish Sea Nettle Jelly and diver Giant Jelly off Coast of Japan Beached Jelly fish Jelly fish Humor Portuguese Man 0’ War (a Hydrozoan), NOT a true jelly fish Portuguese Man 0’ War Tentacles of Physalia physalis Portuguese Man o’ War vs. Box Jelly fish Class Cubozoa: Box Jellyfish Chironex fleckeri the Box jelly fish
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