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Chapter 33- Invertebrates Invert

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					Chapter 33- Invertebrates
        Invertebrates- animals that lack a backbone
33.1: sponges are basal animals that lack true tissues
        Suspension feeders- capture food particles suspended in water
        Spongocoel- central cavity
        Osculum- large opening through which water leaves
        Choanocytes- collar cells, line interior
        Mesohyl- gelatinous region separating cell layers
        Amoebocytes- use pseudopodia to move
        Hermaphrodites- produce both sperm and eggs
33.2: cnidarians are an ancient phylum of eumetazoans
        Gastrovascular cavity- central digestive compartment
        Polyps- cylindrical forms that adhere to substrate, mouth up
        Medusa- flattened, mouth down, move through water
        Cnidocytes- function in defensive and prey capture
        Nematocysts- contain a stinging thread
33.3: lophotrochozoans, a clade identified by molecular data, have widest range of body
        Platyhelminthes- flatworms
        Protonephridia- network of tubules with flame bulbs- ciliated cell
        Ectoprocts- colonial animals that superficially resemble clumps of moss
        Brachiopods- lamp shells
        Molluscs
                 Foot- muscular used for movement usually
                 Visceral mass- contains most internal organs
                 Mantle- tissue that drapes over visceral mass, secretes shell
                 Mantle cavity- water filled chamber
                 Radula- organ used to scrape up food
                 Torsion- only in gastropods, visceral mass rotates 180 degrees
33.4: ecdysozoans are the most species rich animal group
        Cuticle- external coat
        Molting- ecdysis
        Nematodes
        Arthropods- segmented bodies, hard exoskeleton, jointed appendages
                 Open circulatory system- hemolymph is propelled by heart to sinuses
                 Cheliceriforms
                         Chelicerae- clawlike feeding appendages
                         Euryplerids- water scorpions
                         Arachnids- scorpions, spiders, ticks, mites
                         Book lungs- stacked platelike structures contained in internal chamber
                 Myriapods
                         Mandibles- jaw like mouthparts
                 Hexopoda
                         Incomplete metamorphosis- nymphs resemble adults but not completely
                                  mature
                         Complete metamorphosis- larva to adult through pupal stage
                 Crustaceans
                         Isopods- largest groups of crustaceans
                         Decapods- lobsters, crawfishes, crabs, shrimps
                       Copepods- planktonic crustaceans
33.5: echinoderms and chordates are deuterostomes
        Echinoderms- most are slow moving or sessile marine animals
               Water vasculature system- network of hydraulic canals
               Tube feet- function in locomotion, feeding, gas exchange
tion in locomotion, feeding, gas exchange

				
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posted:10/13/2010
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