Transcript Polyp
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 • Mouth pointing in upward direction. • Sessile (coral) Coral polyp Polyp (sea anemone) Mythical Hydra Polyp (Hydra) Perseus slays the Gorgon Medusa C. Medusa • Umbrella shape • Tentacles around mouth • Mouth pointing downward • Motile, Free-swimming • Have D. Tentacles nematocysts (stinging cells) • Coiled thread discharges like a harpoon • Contains neurotoxin • Paralyzes prey Discharged nematocyst Tentacles • Cnidocytes: epidermal cells which are used for attachment, defense, and feeding. • May contain dischargeable nematocysts – long tube armed with spines used to penetrate prey e. Cnidarian Life Cycle Stage 1 – Adult Medusa Stage 2 – Planula larva Stage 3 - Polyp 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 Lion’s mane eats (predators) another jelly B. Process of feeding 1. Tentacles sting prey with nematocysts 2. Tentacles grab prey 3. Prey pulled into mouth Process of feeding 4. Prey stuffed into gastro-vascular cavity (GVC)* 5. GVC makes enzymes, extracellular digestion 6. Undigested food back out mouth *incomplete digestive tract (no anus) Feeding • Gastrodermis – inner tissue layer derived from endoderm. Cells used for food gathering, digestion, and absorption. Lion’s mane jellyfish eating VI. Respiration • Via diffusion • Body is two cell layers thick VII. Internal Transport Via diffusion VIII. Excretion • Via diffusion IX. Response A. No cephalization or nervous system B. Nerve net around mouth IX. Response C. Sensory cells 1. Chemoreceptors (chemicals) 2. Thigmoreceptors (touch) 3. Photoreceptors (light) Ocelli (eyespots) 4. Statocysts (balance) Response • Rhopalium – sensory receptors in the notches at the margin of the medusa in Aurelia (olfactory, statocyst, photoreceptors) • Nerve Ring – encircles the margin of the medusa in Gonionemus X. Locomotion A. Medusa motile, free-swimming B. 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 Reproduction • Gonads – reproductive organs XII. Ecological Role A. Predators and prey B. Neurotoxins in medical research C. Coral – jewelry, building, reefs (surfing!) D. Coral reefs - habitat for many -great biodiversity - protect coastline E. Symbiosis with other organisms Cnidaria Body Structure Cnidaria Body Structure • Manubrium – tubelike structure that hangs from the medusa’s oral surface (mouth is found at the end). • Mesoglea – jellylike layer found between the two tissue layers (epidermis and gastrodermis). Cnidaria Body Structure • Hydrostatic skeleton – water or body fluids confined in a cavity of the body and against which contractile elements of the body wall act. • Statocyst – a small sac surrounding a calcium carbonate structure- “Stone” moves in response to the pull of gravity, initiating nerve impulses. Cnidaria Body Structure • Tentacle – surrounds the mouth. Used for catching prey; contains nematocysts. • Mouth – Points downward in medusa form. Upward in polyp form. Food enters through mouth. • Oral disc – area surrounding mouth. Contains openings which permit water to circulate. Anthozoan Polyp Body Structure • Pedal Disc – found on the bottom of anemones. For some, it is used to glide, but it is also used for asexual reproduction when a piece separates. • Pharynx – connects the mouth to the gastrovascular cavity. • Acontia – “Threads” found at the end of mesenterial filaments which contain cnidocytes. Subdue live prey in the gastrovascular cavity. Class Anthozoa: Sea Anemones 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 Brain Coral Coral Colt Coral Elkhorn Coral Cabbage Coral Flower Coral Feather Coral Gorgonian Fan Coral Lamellina Coral Sun Coral Subergorgia Coral Soft Coral Sea Pen Sea Fan Sea Plume Class Hydrozoa: Green Hydra Hydra Brown Hydra with buds Brown Hydra eating Hydra eating Daphnia • Hydra eats Daphnia Class Scyphozoa: True Jellyfish 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 Phylum Ctenophora • Contains Comb Jellies • Characteristics of Ctenophora: – radial symmetry – Gastrovascular cavity – Rows of ciliated bands, called “comb rows” – No nematocysts; Adhesive structures known as colloblasts Comb Jellies