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1 Phylum Cnidaria BIO 2215 Oklahoma City Community College Dennis Anderson
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2 Phylum Cnidaria Radial symmetry Mouth at oral end surrounded by tentacles. One opening into and out of gastrovascular cavity. Cnidocytes that discharge pneumatocysts Two body forms –Polyp –Medusa Two germ layers Nerve net
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3 Radial symmetry
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4 Mouth and Tentacles
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5 Fig. 13.2
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6 Generalized Cnidarian Life Cycle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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7 Cnidocyte Structure and Nematocyst Discharge Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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8 Diploblastic - 2 germ layers –Epidermis - outer covering (ectoderm) –Mesoglea - middle non-living jelly-like layer –Gastrodermis - lines gastrovascular cavity (endoderm)
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9 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cnidarian Body Wall
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10 Nervous System Nerve cells, arranged in a nerve net.
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11 Class Hydrozoa Freshwater & marine. Cnidocytes present only on epidermis. Medusa (if present) with a muscular velum. Mesoglea without ameboid cells. Asexual reproduction by budding. Sexual reproduction via gametes produced by epidermis & released into water.
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12 Class Hydrozoa Hydra Obelia Gonionemus Physalia
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13 Class Hydrozoa HydraSpermariesSpermaries OvariesOvaries EncapsulatedembryoEncapsulatedembryo Sexual cycle Asexual cycle BuddingBudding
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14 GastrovascularcavityGastrovascularcavity EpidermisEpidermis MesogleaMesoglea GastrodermisGastrodermis Hydra Body Wall
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15 Fig. 13.9
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16 Obelia
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17 Obelia MedusaeGonangium Medusa bud
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18 Class Hydrozoa Gonionemus
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19 Class Hydrozoa Gonionemus Velum
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20 Class Hydrozoa Physalia
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21 Class Scyphozoa Tentacles up to 70 meters in length Cnidocytes present in gastrodermis & epidermis Thick mesoglea contains ameboid cells Gametes produced by gastrodermis All marine
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22 Class Scyphozoa Aurelia
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23 Aurelia Life History Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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24 Fig. 13.18
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25 Planula Larva Ciliated larva then can swim to a new location
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26 Aurelia EggsEggs MesogleaMesoglea GastrovascularcavityGastrovascularcavity MouthMouth
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27 Aurelia Mouth Oral arm Gastric pouch Tentacles
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28 Class Cubozoa Medusa dominant & cuboid Tentacles arise at four corners from blade-like pendalium. All marine Strong swimmers which prey primarily on fish Stings of some may be fatal within minutes to humans.
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29 Class Cubozoa GonadGonad TentacleTentacle PedaliumPedalium
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30 Class Cubozoa Chironex Sea Wasp
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31 Class Anthozoa Medusa stage absent Solitary or colonial Some produce protective skeletons Gastrovascular cavity subdivided by at least 8 mesenteries Cnidocytes on mesenteries Mesoglea contains ameboid cells All Marine
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32 Class Anthozoa Sea Anemone
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33 Class Anthrozoa Metridium MouthMouth TentaclesTentacles PharynxPharynx SeptumSeptum Gastrovascular cavity
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34 Symbiosis
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35 Class Anthozoa Corals Protective skeleton of calcium carbonate Polyp retracts when not feeding
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36 Zooxanthellae Photosynthetic dinoflagellates (brown) Live in corals Provide nutrients for coral by photosynthesis Mutualism
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37 Corals Colony of interconnected polyps
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38 Class Anothozoa Meandrina Brain Coral
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39 Class Anothozoa Gorgonia Sea Fan
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40 Class Anothozoa Tubipora Pipe Organ Coral
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41 Class Anothozoa Actinodiscus Mushroom Coral
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42 Class Anothozoa Acropora Staghorn Coral
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43 Coral Reefs Formed over thousands of years from successive layers of coral skeleton deposits (calcium carbonate forms underwater mountains of coral animal skeletons) The underwater equivalent of the amazon jungle- very high species diversity and biomass Reefs contain sponges, colonial hydrozoans, anemones, many varieties of coral, fish, many types of worms we’ve not discussed, not to mention bryozoans, ctenophores, protists, bacteria, etc etc..
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44 Coral Reef Ecosystem Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Photo © McGraw-Hill Higher Education, Barry Barker, Photographer
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45 Anthozoa ScyphozoaCubozoa Hydrozoa Radial symmetry, cnidocytes, planula larva Septa divide gastrovascular cavity Medusa cuboidal Polyp stage reduced Loss of medusa Cladogram of Cnidaria
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46 The End
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