1 Cnidarians & Ctenophorans 1copyright cmassengale

22 CNIDARIANS

3 Phylum Cnidaria About 9000 species Most are marine (jellyfish, coral, sea anemones, Portuguese man-of war) Hydras are found in freshwater All have arm-like tentacles 3copyright cmassengale

4 Cnidarian Characteristics Radial symmetry Hollow gut -Gastrovascular cavity has single opening (serves as both mouth and anus) Two tissue layers (diploblastic) Outer epidermis and inner gastrodermis 4copyright cmassengale

5 Cnidarian Characteristics Either tubular or bell shaped Tentacles surround mouth Only animal with cnidocytes (stinging cells) found in the tentacles Nematocyst – coiled, harpoon-like stinger inside cnidocyte that shoots out 5copyright cmassengale

6 Cnidarian Characteristics Cnidocytes contain poison to paralyze prey Tentacles bring food into mouth Inner gastrodermis secretes digestive juices into gastrovascular cavity which digests food and circulates nutrients 6copyright cmassengale

7 Extracellular Digestion 7 Food digested outside of cells copyright cmassengale

8 Cnidocyte Coiled nematocyst copyright cmassengale

9 Nematocyst Barbed, threaded stinger capsule’s lid trigger nematocyst 9copyright cmassengale

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11 Cnidarian Systems Have a simple nerve net & sensory receptors Muscles help in directional movement & capturing prey copyright cmassengale

12 mesoglea-filled bell tentacles 12 Jellylike mesoglea between two cell layers supports cnidarian copyright cmassengale

13 Two Main Body Plans of Cnidarians epidermis mesoglea gastrodermis Medusa Polyp UPRIGHT TENTACLES TENTACLES HANG DOWN mouth Mesoglea THICK Mesoglea THIN copyright cmassengale

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15 Cnidarian Diversity Scyphozoans: Jellyfish Anthozoans: Sea anemones Corals Hydrozoans: Hydra Cubozoa Box Jellies 15copyright cmassengale

16 Cnidarian Diversity 16 Sea AnemoneCoral polyps Jellyfish Coral polyps copyright cmassengale

17 Scyphozoans copyright cmassengale

Scyphozoan Characteristics Jellyfish Medusa is dominant body form Go through small polyp stage during life cycle Stinging tentacles May live close to shore or the open ocean

Parts of a Jellyfish 19

Some Jellyfish Show Luminescence 20

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Jellyfish Life Cycle

23 Anthozoans copyright cmassengale

24 Anthozoan Characteristics Sea Anemones  Brightly colored & Resemble flowers  Solitary polyps  Feed on invertebrates & fish Corals  Most are colonial  Build limestone case  Live as polyps in their case copyright cmassengale

25 Sea Anemones & Coral Exist only as Polyps Clownfish live in anemone tentacles Corals build a limestone case which build up & form reefs ANEMONE CORAL copyright cmassengale

26 Distribution of Coral Reefs copyright cmassengale

27 Hydrozoans copyright cmassengale

28Hydrozoans Hydra Exist as polyps in their dominant form. Reproduce by budding Freshwater only Form resistant zygotes when environment is bad Move by somersaulting with tentacles copyright cmassengale

29 Hydra copyright cmassengale

30 Hydra Feeding copyright cmassengale

31 Food in Gastrovascular Cavity copyright cmassengale

32 Colonial Hydrozoan (not a single organism Tentacles sting prey such as fish & humans Polyps in colony feed Has gas-filled air float Portuguese man-of-war copyright cmassengale

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copyright cmassengale36 Blue Dragon Mollusk – Man of War Predator!!

37 Hydrozoan Life Cycle Most hydrozoans alternate polyp and medusa forms, as in the life cycle of Obelia 37copyright cmassengale

38 Obelia Life Cycle (Hydrozoan) Larva called a planula reproductive polyp female medusa male medusa sperm zygote ovum planula polyp forming feeding polyp Fig a, p.411 copyright cmassengale

39 Cubozoans Box JellyFish 39copyright cmassengale

Chironex fleckeri copyright cmassengale40 Australian shores 100 human deaths in the last 100 years Venom can kill in 3 minutes

41 CTENOPHORANS copyright cmassengale

42 Ctenophoran Characteristics Called comb jellies All marine Approximately 100 species May be spherical, ovoid, or elongate in appearance Bioluminescent copyright cmassengale

43 Ctenophoran Characteristics Radial symmetry Have eight plates of fused cilia that resemble combs Move by beating cilia Most of the body is jelly-like mesoglea Body & tentacles covered with sticky mucus to catch prey copyright cmassengale

44 Comb Jelly Anatomy 44copyright cmassengale

45 Ctenophore: Comb Jelly 45 Beating Cilia copyright cmassengale

46 Ctenophore

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