Outer covering perisarc non living Chitinous impregnated form chitin structural

Outer covering perisarc non living chitinous

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Outer covering – perisarc – non-living Chitinous – impregnated form chitin (structural sugar) Protective Chitin – similar to keratin which is a protein that grows hair and nails o Cups at high end have polyps and feed o Underneath have medusa – sexual phase o Zooids – individual polyp organisms Feeding – hydranths Tubular, bottle shaped, vase-like All have terminal mouth All have tentacle encircling mouth Perisarc extends to cover and protect zooid Capture crustaceans, worms, larvae Obelia Reproduction o Budding Increases size of colony Feeding polyp buds Medusa buds – from ganangium (reproductive bud) Young medusa Free swimming Leave colony Mature Produce gametes May fertilize colony If forms zygote will settle somewhere Through asexual reproduction, new colony forms Physalia o Portuguese man-of-war o Colony of floating medusa and polyps o Long tentacles
o Gas-filled-sac – float o Dangerous nematocysts o Purple tentacles – where all members of colony exist ° Class – Scyphozoa Larger jellyfish “Cup” shaped animals As large as 2 meters in diameter Tentacles can be 70cm long Most marine Most free-floating, free-swimming Some Seissile Adults tend to be medusas Schyphozoa o Thick mesoglea – buoyant o Variationin presence and size of tentacles o Margin of bell scalloped o Each incident has sense organ – rhopalium Equilibrium Tactile sense Some have light sensitivity o Orients scyphoza o Mouth on subumbrella side o At end of projection called manubrium Manubrium has four oral arms Oral arms used to capture prey o Gastric pouches – aid with digestion and subdue prey; also turn into gonads later on Four Extend to gastric filaments Filaments have nematocysts to subdue prey Not considered organs because they are too simple
Scyphozoa – Reproduction o Diocius o Gonads in gastric pouches of female o Sperm released into water o Carried by cilia to gastric pouch of female o Zygote develops in open water or in folds of oral arms o Ciliated larva o Becomes polyp form – attaches o Forms saucer-like buds – strobila o Each strobila breaks off and becomes new jellyfish Aurelia o Short tentacles o Eats plankton o Has food pockets on bell margin o Food brought to mouth via cilia o Waste expulsion and water flow through gastrovascular cavity by cilia Class – Cubozoa o Medusa form is dominant o Polup is mostly unknown o “squarish” o Tentacles at each corner of square o Not scalloped o Edge turns inward – velarium – increases swimming efficiency o Feeds on fish o Fatal to humans o Most of life cycle unknown Class Anthozoa o “flower animals” o No medusa stage o All marine
o Deep or shallow water o Polar or tropical water o Solitary or colonial o Much size variation o 100% polyps o More advanced structures o Don’t have to be be free swimming ever; heavier; more muscular; more complex feeding system o Sea anemones, corals o Subclasses Zoanthatria Sea anemones Hard corals Ceriantipatharia Tube anemones Thorny corals Alcyonaria Soft corals

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