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Invertebrates Cnidarians a.k.a. Coelentrates http://images.google.com/imgres?imgurl=http://www.nature.com/nrg/journal/v2/n1/images/nrg0101_033a_f1.gif&imgrefurl=http://www.nature.com/nrg/journal/v2/n1/fig_tab/nrg0101_033a_F1.html&h=586&w=600&sz=151&hl=en&start=101&um=1&usg=__gZHBWlx7DZmkWnjNa0aVzIJQTsQ=&tbnid=l6634ZL0ujoJgM:&tbnh=132&tbnw=135&prev=/images%3Fq%3Dcnidarian%26start%3D100%26ndsp%3D20%26um%3D1%26hl%3Den%26safe%3Dactive%26rls%3Dcom.microsoft:*:IE-SearchBox%26rlz%3D1I7GGLD%26sa%3DN
www.oceanicresearch.org mediumrarecreations.com http://images.google.com/imgres?imgurl=http://www.eurekalert.org/multimedia/pub/web/5544_web.jpg&imgrefurl=http://www.eurekalert.org/multimedia/pub/5544.php&h=298&w=400&sz=8&hl=en&start=78&um=1&usg=__ApgUaa5NOZiJ6eF_zndANErI688=&tbnid=v1FKrUhcjgsyqM:&tbnh=92&tbnw=124&prev=/images%3Fq%3Dcnidarian%26start%3D60%26ndsp%3D20%26um%3D1%26hl%3Den%26safe%3Dactive%26rls%3Dcom.microsoft:*:IE-SearchBox%26rlz%3D1I7GGLD%26sa%3DN
Characteristics • “Cnidos” Name means stinging needles • true tissues, 2 tissue layers, tentacles, stinging cells, radial symmetry • Life cycle - • Polyp – stationary, tentacles and mouth face up • Ex. Corals and anemones • Medusa – move with the current, tentacles and mouth face down • ex. Jellyfish and man o war
Examples of Cnidarians • coral, anemone, hydra, • jellyfish, Portuguese man-of-war http://images.google.com/imgres?imgurl=http://www.roumazeilles.net/news/en/wordpress/wp-content/uploads/2007/10/giant_jelly_fish.jpg&imgrefurl=http://www.roumazeilles.net/news/en/wordpress/2007/10/07/giant-jellyfish/&h=381&w=500&sz=102&hl=en&start=20&um=1&usg=__Vj2R-kvbALTLH-IOofJ9bMC_K-k=&tbnid=M3DVmObBIQkgIM:&tbnh=99&tbnw=130&prev=/images%3Fq%3Djellyfish%26um%3D1%26hl%3Den%26safe%3Dactive%26rls%3DGGLD,GGLD:2005-16,GGLD:en%26sa%3DN http://www.naturalsciences.org/education/deepsea/images/man-o-war.jpg
Support • water pressure
Movement • muscle cells and a ring of muscle around the bell of the medusa form
Collecting food • stinging cells - nematocysts, tentacles
Digestion • one cavity – gastrovascular • Food comes in wastes comes out same hole • Nutrients transported by diffusion
Circulation & Respiration • none
Nervous system • a nerve ring in the mesoglea (middle layer)
Reproduction • budding - polyp form • sexual – medusa form - egg / sperm • Some alternate generations
Importance to nature • big link in food chain, feed on plankton, corals provide home for most of the ocean’s species
Importance to economy • coral, anemone
Define these terms • Medusa • Polyp • Mesoglea • Alternate generations
Video on cnidiarians • Google Image Result for http://www.scivee.tv/assets/videothumb/2753