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Cnidarians

Cnidarians. Sandra Benito J.H., 9B. Facts. Name : Cnidarians Before: Coelenterata phylum, meaning "hollow guts." Included certain ctenophores and sponges. From the Greek "cnidos," meaning "stinging nettle.“ Number of species currently existing: 10,105 species Taxonomic Classification:

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Cnidarians

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  1. Cnidarians Sandra Benito J.H., 9B

  2. Facts

  3. Name: Cnidarians • Before: Coelenterata phylum,meaning "hollow guts." • Included certain ctenophores and sponges. • From the Greek "cnidos," meaning "stinging nettle.“ • Number of species currently existing: 10,105 species • Taxonomic Classification: • Domain:Eukaryota • Kindom: VI. Animalia • Phyla: B.Cnidaria • Class:Cubozoa (Box jellies) Swimming • Class:Scyphozoa (Jellyfishes) Swimming • Class:Anthozoa (Anemones and corals) Sessile • Class: Hydrozoa (Hydra) Both

  4. Characteristics

  5. Found in marine environments. • Two basic body types: • Polyps • Medusae • Tentacles • Venomous cell organelles (cnidea) • Gastrovascular cavity • Three-layered body; epidermis, mesoglea and gastrodermis • Radially symmetric • Carnivorous • Solitary or colonial • Asexual and/or sexual reproduction • Nervous system • No cardiovascular system

  6. History

  7. Fossil history: • Vendian/Ediacaran period • 650 to 540 million years ago • Soft-bodied organisms • Cambrian period - coral fossils • Early Ordovician - more developed corals

  8. Generalized Life CycleAnd Life Expectancy

  9. Life span is undetermined. • Life cycles vary by class and species • Some skip stages (e.g. Hydra) • Alternation of generations (e.g. Obelia) • Asexual reproduction medusae grows on external tissue • Matured medusae swim away • Sexual cells released • Eggs are fertilized • Zygote/planula settles and develops into a polyop

  10. Digestive System

  11. Absorbdissolvedorganicchemicals • Filterfoodparticles • Nutrientsfromendosymbioticalgae • Predate • Crustaceans and plankton • Medusae forms sink on top of the prey • Gastrodem layer releases enzymes that kill the prey • Cellsabsorbthenutrients • Nutrients spread by diffusion or mobile cells • Indigestible remnants are ejected

  12. Respiratory andCirculatory System

  13. No circulatory system • No respiratoryorgans • Absorb/expel O and CO2 into water • Water in digestive cavity is expelled

  14. Sensory System

  15. Simple sensorysystem • Net of nerves made of sensitive neurons • Sensitive neurons are connected by chemical synapse • Neuron sends neurotransmitter (chemical) to cell group

  16. Bibliography • New Oxford American Dictionary • http://en.wikipedia.org/wiki/Cnidaria • http://waynesword.palomar.edu/trnov01.htm#animals • http://www.buzzle.com/articles/jellyfish-facts-for-kids.html • http://animals.about.com/od/cnidarians/p/cnidaria.htm • http://nationalzoo.si.edu/Animals/Invertebrates/Facts/cnidarians/default.cfm • http://www.oceaninn.com/the-nature-preserve/cnidarians/ • http://mapress.com/zootaxa/2011/f/zt03148p012.pdf • http://animals.about.com/od/cnidarians/ss/cnidarians.htm • http://www.ucmp.berkeley.edu/cnidaria/cnidariafr.html • http://www.angelfire.com/moon2/asciencems/ • http://zoology.muohio.edu/crist/Zoo312/Cnidaria.html • http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/bio%20102/bio%20102%20lectures/nervous%20system/nervous1.htm

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