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Worms & Mollusks Mrs. Wetzel Biology
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Review 5 kingdoms -Prokaryotes * -Protista * -Fungi * -Plants * -Animals
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Review Animal Kingdom –Invertebrates Porifera * Cnidarians * Worms Molluska Arthropods Echinoderms
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Review Vertebrates –Fish –Amphibians –Reptiles –Mammals
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Worms Three Phyla of worms –Platyhelminthes Flatworms –Nematoda Round worms –Annelida Segmented worms
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Platyhelminthes Flat worms –Flatworms are soft flattened worms that have tissues and internal organ systems. –They are the simplest animals to have three germ layers, bilateral symmetry and cephalization
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Platyhelminthes Examples of flatworms are –Planaria –Flukes –Tapeworms
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Platyhelminthes Respiration, circulation, excretion all depend on diffusion. Flame cells are specialized to remove waste
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Platyhelminthes Response- –Platyhelminthes have a collection of nerve cells near the head called ganglion. They are not complex enough to be called a brain. –Eyespot is also found on flatworms. It is used for detecting light
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Platyhelminthes Movement- Flatworms move using cilia found on epidermal cells, or by twisting in the water
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Platyhelminthes Classification- –Turbellarians- free living in water –Bottom dwellers eat decaying material on the bottom –Most famous = planaria
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Platyhelminthes Classification –Trematodes- parasitic –Most famous = flukes
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Fluke Life Cycle
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Platyhelminthes/Flukes Schistosomiasis- rampant in areas with poor sewage systems (pee/ poo where you drink/ bathe) Schistosomiasis eggs accumulate in the blood vessels clogging heart & causing tissue decay * Parasitic flat worms have a slightly thicker coating that protects them from being digested by their host= tegument
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Schistosomiasis
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Platyhelminthes Classification- Cestoda aka Tapeworm Live inside the intestine of the host Attach with the scolex
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Nematoda Nematodes= Roundworms
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Nematoda Feeding- many are free living carnivores that can live in moist soil, some are marine
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Nematoda Respiration/ Circulation/ Excretion –There is NO internal transport system, they depend on diffusion for transporting cellular metabolic waste such as ammonia.
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Nematoda Response= Ganglia same as flatworms (platyhelminthes)
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Nematoda Reproduction= Sexual
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Trichinosis Adult worms live and mate in the intestine of the host- eggs are released and burrow into the intestinal wall. The larva then travel into the bloodstream and organs causing pain. The life cycle is complete when something ingests the muscle infected with tissue infected with eggs
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Filarial Worms Elephantiasis is cause when a large number of filarial worms block the passage of fluids within the lymph vessels of a part of the body
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Ascarid Worms Ascaris matures in the intestine of the host reaching up to 50 cm. The Ascaris causes severe malnutrition in more than 1 billion people worldwide
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Hookworms Hookworms live in the soil and enter the body through an exposed foot. They then borrow into the bloodstream where they set up shop sucking the blood of their host causing weakness and poor growth
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Phylum Annelida Segmented worms –Animals with segmented bodies and a true coelom lined with mesoderm
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Phylum Annelida Feeding and digestion- feeding varies Annelids pull food into the pharynx it is then stored in the crop then eventually pushed down into a gizzard where it is ground up and digested
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Phylum Annelida Annelids have a closed circulatory system! Blood is circulated through a series of blood vessels
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Phylum Annelida Respiration- Marine annelids breath through gills Terrestrial annelids have very moist skin which allows for gas exchange on the epidermis.
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Phylum Annelida Excretion- –Solid waste is passed through the anus –Liquid waste is filtered from the blood by nephridia
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Phylum annelida Movement –Longitudinal Muscles & circulatory muscles contract alternately allowing the worm to move –Marine annelids have parapodia= paddles
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Phylum Annelida Reproduction –Sexual –Asexual –Hermaphrodites- worms rarely fertilize themselves. Usually two worms will attach at each others clitellum and drop off some sperm. When eggs are ready to be fertilized the stored sperm from the other worm will be used. The thicken clitellum will then slip off of the worms body with the fertilized eggs and create a cocoon
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Phylum Annelida Classification –Oligochaetes- earth worms –Hirudinea Leeches- external parasites –Polychaeta- marine worms
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Phylum Molluska One of the oldest and most diverse Phyla Soft bodies animals with an internal or external shell
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Phylum Molluska Body Plan- usually soft bodies animals with an internal or external shell –Shell –Visceral Mass –Mantle Cavity –Foot Molluska and annelids are closely related as their larva is similar
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Phylum Molluska Feeding- herbivores, carnivores, filter feeders, detritivores, parasites –Snails & Slugs eat using their radula – looks like a big tongue –Octopi can produce toxins to poison their prey and then pull them into their jaws using their tentacles
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Phylum Molluska Respiration- Aquatic Mollusks breath using gills Terrestrial animals breath through gas exchange over the mantle cavity
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Phylum Molluska Circulation- open circulatory system- organs are bathed with blood in sinuses
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Phylum Molluska Excretion- Nephridia removes ammonia
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Phylum Molluska Response- Varies greatly –Bivalves- pretty simple small ganglia –Gastropods- small antennae that can sense their environment –Cephalopods- Highly developed brain Can remember things Reward & Punishment
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Phylum Molluska Movement- varies
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Phylumn Molluska Reproduction- –Sexual –Asexual –Hermaphrodites
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Phylum Molluska Classification -Bivalves; Clams, mussels, oysters -Gastropods; Snails, slugs -Cephalopods; Octopus, squid, nautilus.
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Gastropods
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Bivalves
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Cephalopods
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