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05 ppt cbidaria ppt 05 ppt Cnidaria.ppt
- 1. Phylum Cnidaria (formerly Coelenterata) G:stinging thread bearing
- 2. The Hydra • Powersof regeneration stem from omnipotent cells
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- 4. Phylum Cnidaria • Allhave nematocysts (cnidae) • Have radial symmetry • 2 layers (epidermis and gastrodermis) • Mesoglea between epidermis and gastrodemrmis is a non-living layer • All have tentacles surrounding the mouth and only a single opening to the digestive system
- 5. Phylum Cnidaria • BodyPlan: medusa and polyp • Planula larvae in the life cycle • Have muscles and nerves • Muscles are not true muscles— epitheliomuscular cells
- 6. Life Cycle ofa Cnidaria
- 7. Cnidae • Are organelles secretedfrom cnidoblasts or nematocysts • Each cnida can be discharged only once • Mechanism of expulsion currently unknown
- 8. Class Scyphozoa (Asexual reproductionby strobilation (budding)) • The true jellies • Monoecious • Sperm+egg= planula Manubrium - muscular cylinder that ends in the mouth
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- 10. Class Cubozoa (medusa wboxlike body; rhopalia with complex, lensed eyes) • Box jellyfish/ seawasp (cubomedusae) • Restricted to tropical and subtropical waters • Most derived cnidarians Chironex fleckeri
- 11. Jellyfish Emergency • Pourvinegar over affected part, NEVER alcohol or water • Children must be brought to the hospital ASAP for medical treatment
- 12. Class Hydrozoa • Polypform predominates • Portuguese man of war • Hydrocorals– very much like corals
- 13. Class Hydrozoa • OrderHydroidea (hydra) • Order Siphonophora – Portuguese man-o-war Physalia sp. – Floating colony of polymorphic hydrozoans • nectophores,phyllozooids, gastrozooids, gonozooids, dactylozooids • Order Hydrocorallina
- 14. Class Anthozoa (reef-building corals,anemones, sea fans, sea pansies) • Absence of medusa • Sea anemones and corals • 70% of all cnidarian species • Subclass Hexacorallia • Subclass Octocorallia • Coral wars Anatomy of a polyp (Source: NOAA)
- 15. Class Anthozoa • Coralspawning 4 days after the new moon in the summer
- 17. Subclass Hexacorallia • Canbe ahermatypic or hermatypic (reef- building corals) • Endosymbiont photosynthetic dinoflagellates called zooxanthellae (Symbiodinium) play an important role in coral growth. • The symbiosis is quite fragile and can be thrown off balance by stressors in the environment.
- 18. Subclass Octocorallia • Seafans, seawhips (gorgonians), pipe corals • Brain corals are also octocorals
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- 21. Coral Reefs • Coralsin a reef are not stationary—there is a war for space going on all the time. • The complex interactions and many micro habitats in a coral reef are key to its high species diversity. • This ecosystem is being threatened by pollution, ocean acidification, and bleaching higher sea surface temperatures.