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Invertebrates Porifera • Sponges • Asymmetrical Porifora • Response/Movement • sessile • no nervous system • cell detect external stimuli and respond by closing their pores to stop water flow Porifora • Feeding/Digestion • filter feeders • digestion of nutrients takes place within each cell Porifora • Circulatory/Respiratory • cells filter oxygen out of the water individually Porifora • Reproductive • asexually by fragmentation, budding, or gemmules • most reproduce sexually (release sperm in the water, eggs kept inside) • most are hermaphroditic • larva can swim • Examples: Cnidaria • Jellyfish • Sea anemone • Coral • Radial symmetry Cnidaria • Response/Movement • nerve net conducts impulses to & from all parts of the body Cnidaria • Feeding/Digestion • Stinging cells called cnidocytes used to capture prey • Gastrovascular cavity used to digest • Waste excreted through the mouth • No excretory organs Cnidaria • Circulatory/Respiratory • No blood vessels, respiratory systems Cnidaria • Reproductive • • • • Polyp & medusa form Medusas release eggs & sperm into the water Zygotes become polyps Polyps reproduce asexually to form medusa Platyhelminthes • Examples • Tapeworms • Flukes • Planaria • Bilateral symmetry Platyhelminthes • Response/Movement • two nerve cords with connecting nerve tissue run the length of the body • ganglia at anterior end • move by contracting muscles in the body wall • glide by using cilia • mucus covering enables them to stick to surfaces Platyhelminthes • Feeding/Digestion • feed on dead or slow moving organisms • pharynx extends out of mouths to digest and take in food • waste excreted out the mouth • parasitic worms have hooks and suckers • some take in nutrients through their skin Platyhelminthes • Circulatory/Respiratory • no circulatory/respiratory organs • cells use diffusion to move dissolved oxygen/nutrients to all parts of their bodies • carbon dioxide/wastes are removed by diffusion • flame cells sweep water/waste into tubules to exit through pores Platyhelminthes • Reproductive • hermaphroditic • exchange sperm, eggs fertilized internally • regeneration to reproduce asexually Nematoda • Examples • Vinegar eel • Ascarids • Trichinella • Bilateral symmetry Nematoda • Response/Movement • Ganglia and nerve cords coordinate nematode responses • Sensitive to touch & chemicals • Some have structures to detect differences between light & dark • Muscles cause bodies to move in thrashing way Nematoda • Feeding/Digestion • • • • Most free-living, some parasites Predators, scavengers First to have a body cavity Movement of food is one way Nematoda • Circulatory/Respiratory • No circulatory/respiratory organs • Diffusion moves nutrients/gases through body • Most exchange gases & excrete metabolic waste through skin Nematoda • Reproductive • Sexually • Fertilization is internal • Larvae hatch from eggs then grow into adults • In parasites, development involves more than 1 host & different parts of the body Trichinella larvae encased in muscle cells Mollusk • Examples: • • • • Octopus Squid Clam Snail • Bilateral symmetry Mollusk • Response/Movement • • • • • • Nervous systems Some have brains Some have complex eyes similar to humans Clams use muscular foot to burrow Two shells can clap them together to move Squids take water into cavity & expel it thru siphon Mollusk • Feeding/Digestion • Many us radula to scrape food into their mouths • Some are filter feeders • Complete guts with digestive glands, stomachs, & intestines • One way system Mollusk • Circulatory/Respiratory • • • • Most have gills Land mollusks use mantle cavity Chambered heart, open circulatory system Some have closed circulatory system (for faster/more efficient movement) Mollusk • Reproductive • • • • • Sexually Release eggs & sperm into water Fertilization is external Some hermaphroditic Larvae form Annelida • Examples • Earthworm • Leech • Bilateral symmetry Annelida • Response/Movement • anterior segments are modified to sensing the environment • brain & nerve cords composed of ganglia • can detect light/vibes • contracts circular muscles to move • setae to anchor the worm Annelida • Feeding/Digestion • digestive tract runs thru segments • food passes thru pharynx, crop, & gizzard (contains hard particles to help grind soil & food) • nutrients absorbed from the intestine Annelida • Circulatory/Respiratory • • • • • • most have closed circulatory system blood vessels transport oxygen/nutrients large vessels at anterior end serve as heart respire thru skin aquatic have gills nephridia help eliminate wastes Annelida • Reproductive • • • • sexually & asexually some are hermaphroditic fragmentation in earthworms, clitellum produces a cocoon from which babies hatch Arthropoda • Examples • Spiders • Insects • Crustaceans • Bilateral Symmetry Arthropoda • Response/Movement • Double chain of ganglia • Fused pairs of ganglia in head make the brain • Compound eyes, some have multiple simple eyes • Tympanum for hearing • Some use pheromones • Well developed musculature Arthropoda • Feeding/Digestion • Most have mandibles for biting & chewing • Herbivores, carnivores, omnivores, filter feeders, parasites • Complete one way digestive system Arthropoda • Circulatory/Respiratory • Use gills, tracheal tubes or book lungs • Rely on circulatory system to transport nutrients/ remove wastes • Heart • Malpighian tubules remove wastes from blood Arthropoda • Reproductive • • • • • Sexually Separate sexes Crustaceans brood Spiders/insects incubate their eggs Bees care for their young Echinodermata • Examples • Starfish • Sea urchins • Radial symmetry Echinodermata • Response/Movement • nerve rings surround the mouth with branching nerve cords connecting to other body areas • sensory neurons respond to touch, chemicals, currents, & light • cirri, tube feet Echinodermata • Feeding/Digestion • sea stars push their stomach out of their bodies then use cilia to bring in digested food • predators or scavengers • tube feet • variety of feeding strategies Echinodermata • Circulatory/Respiratory • oxygen diffuses from the water through the thing membranes of the tube feet • some use osmosis through all thin body membranes • other have skin gills • circulation in the coelem, excretion thru membranes Echinodermata • Reproductive • sexually • females shed eggs/males shed sperm into water • eggs develop into free swimming larvae
