Transcript Cnidarians
Cnidarians • Hydrozoa – Hydras • Scyphozoa – Sea Jellies , “ Jelly fish” • Anthozoa- Sea Anemones Cnidarians • Cnida- “nettle” • Diploboastic – – Gastrodermis & Epidermis • • • • • Radial Symmetry Cnidocytes- Nematocysts Polyp – Medusa Incomplete digestive tract Simple Nervous net, contractile cells Polyp Medusa Oral Aboral Aboral Oral Cnidarian Body Forms Cnidarian Cnidocytes Cnidocyte trigger Symmetry Hydra nutrition Cnidarian circulation Simple Nervous net Hydra sp. Epidermis Cross section Nematocysts Female Male Obelia Hydranth Gonangium Medusa Buds Ceonosarc Gonotheca Perisarc Perisarc Hypostome Hydrotheca Ceonosarc Obelia sp. life cycle Obelia sp. medusae Protective pantyhose worn by north Queensland life savers Near fatal sting by C. fleckeri on a 13 year old boy at Cairns, Australia Cnidarian Body Forms Cnidarian Cnidocyts Hydra w.m. Hydra Class Scyphozoa • Example – Aurelia (Moon Jelly) Planula of Aurelia Aurelia Scyphistoma - & strobilus Aurelia sp. ephrya Ephyra anatomy Aurelia sp. 2 3 4 1 5 6 1 2 3 4 5 6 8 7 Medusa anatomy Aurelia Anatomy Class Anthozoa no medusa stage • Examples – Sea Anemones: Metridium sp. – Corals (hard and soft) Sea Anemones Metridium External Anatomy Metridium c.s. Metridium c.s. Enlargement of Pharynx • • • • • 1. Siphonoglyph 2. Retractor muscle 3. Primary septum 4. Pharynx 5. Gastrovascular Cavity 1 2 11 3 10 4 9 5 6 7 8 Close-Up of Septa • • • • • • 1. Primary septum 2. Secondary septum 3. Tertiary septum 4. Retractor muscle 5. Septal filament 6. Gastrovascular cavity Close-Up of Body Wall • • • • • • 1. Epidermis 2. Mesoglea 3. Gastrodermis 4. Septal filament 5. Primary septum 6. Secondary septum Phylum Ctenophora • Comb jellies possess rows of ciliary plates and adhesive colloblasts • Comb jellies use retractable tentacles to capture food. PHYLUM CTENOPHORA • Characteristics – Comb plates – Colloblasts (glue cells) Pleurobrachia Ctenophorans