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

10 copyright cmassengale

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

14 copyright cmassengale

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 Anthozoans copyright cmassengale

18 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

19 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

20 Distribution of Coral Reefs copyright cmassengale

21 Hydrozoans copyright cmassengale

22Hydrozoans Hydra Exist only as polyps Reproduce by budding Freshwater only Form resistant zygotes when environment is bad Move by somersaulting with tentacles copyright cmassengale

23 Hydra copyright cmassengale

24 Hydra Feeding copyright cmassengale

25 Food in Gastrovascular Cavity copyright cmassengale

26 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

27 copyright cmassengale

28 Hydrozoan Life Cycle Most hydrozoans alternate polyp and medusa forms, as in the life cycle of Obelia 28copyright cmassengale

29 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

30 Cubozoans Box JellyFish 30copyright cmassengale

31 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 33

Some Jellyfish Show Luminescence 34

35

Jellyfish Life Cycle

37 CTENOPHORANS copyright cmassengale

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

39 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

40 Comb Jelly Anatomy 40copyright cmassengale

41 Ctenophore: Comb Jelly 41 Beating Cilia copyright cmassengale

42 Ctenophore

43