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PHYLUM PLAT Y HELMINTHES (“FLAT WORMS !”)

Hello!. PHYLUM PLAT Y HELMINTHES (“FLAT WORMS !”). Diana Luo Hong Joo Kim Carrie Yang Period 5. http://clean-water.uwex.edu/pubs/clipart/critters.plan.htm. CLASSES OF FLATWORMS (TURBELLARIA). Most are marine organisms, some are freshwater All are free-living organisms

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PHYLUM PLAT Y HELMINTHES (“FLAT WORMS !”)

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  1. Hello! PHYLUM PLATYHELMINTHES(“FLAT WORMS!”) Diana Luo Hong Joo Kim Carrie Yang Period 5 http://clean-water.uwex.edu/pubs/clipart/critters.plan.htm

  2. CLASSES OF FLATWORMS (TURBELLARIA) • Most are marine organisms, some are freshwater • All are free-living organisms • Feeds on smaller animals, dead animals • Dugesia “planarians” (about 4,500 species) http://www.thaigoodview.com/library/contest2551/science04/119/kingdon_animalia/Class%20Turbellaria.htm Diana Luo, Hong Joo Kim, Carrie Yang

  3. CLASSES OF FLATWORMS (MONOGENEA) • Marine and freshwater parasites • Most are external parasites of fish • Relatively simple life cycle • Monogeneans (about 1,100 species) http://simple.wikipedia.org/wiki/Monogenea Diana Luo, Hong Joo Kim, Carrie Yang

  4. CLASSES OF FLATWORMS (TREMATODA) • Suckers for attaching to internal organs or outer surfaces of the host • Many require an intermediate host in which larvae develop • Trematodes, flukes (about 11,000 species) http://biodidac.bio.uottawa.ca/thumbnails/filedet.htm?File_name=Trem054p&File_type=gif Diana Luo, Hong Joo Kim, Carrie Yang

  5. CLASSES OF FLATWORMS (CESTODA) • Live mostly inside vertebrates & are parasites • Flat, slender, long bodies • Scolex – suckers + hooks • Tapeworms (3,400 species) http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20102/Bio%20102%20Laboratory/Animal%20Diversity/Lophotrochozoans/Lophotrochozoans.htm Diana Luo, Hong Joo Kim, Carrie Yang

  6. BODY SYMMETRY…& BODY CAVITY? • BILATERAL symmetry (identical shape on either side) • Unlike other bilaterians, flatworms do NOT have body cavity between the digestive cavity and outer body wall. http://www.cartage.org.lb/en/themes/sciences/zoology/biologicaldiverstity/AnimalsI/AnimalsI.htm Diana Luo, Hong Joo Kim, Carrie Yang

  7. NERVOUS SYSTEM • Flatworms have a Central Nervous System (CNS) – the brain and the ventral nerve cords • A pair of ganglia is located at the anterior end http://www.cartage.org.lb/en/themes/sciences/zoology/biologicaldiverstity/AnimalsI/AnimalsI.htm Diana Luo, Hong Joo Kim, Carrie Yang

  8. SENSORY STRUCTURES/FEATURES • Ganglia, or clusters of neurons, present at the anterior end  demonstrates cephalization, trend in which nervous tissue becomes concentrated at one end • A planarian’s head is equipped with a pair of light-sensitive eyespots and lateral flaps that function mainly to detect specific chemicals. http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb5pg5.htm Diana Luo, Hong Joo Kim, Carrie Yang

  9. CIRCULATORY SYSTEM • They have no organs specialized for circulation • A muscular pharynx that leads to the digestive system is present instead http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb5pg5.htm Diana Luo, Hong Joo Kim, Carrie Yang

  10. DIGESTIVE SYSTEM • They have a gastrovascular cavity with only one opening. The many branches of this distribute food throughout the animal http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb5pg5.htm Diana Luo, Hong Joo Kim, Carrie Yang

  11. EXCRETORY SYSTEM • They have a excretory system that eliminates nitrogenous waste (ammonia) by diffusion across the body surface. • Simple excretory apparatus (which consists of ciliated cells called flame bulbs that waft fluid through branched ducts opening to the outside) functions to maintain osmotic balance with their surroundings Diana Luo, Hong Joo Kim, Carrie Yang

  12. LOCOMOTION/MUSCULATURE • Glide along surfaces on mucus that they secrete • Others use muscles to swim through water with an undulating motion • Planarians move by using cilia on their ventral epidermis http://www.deepseaimages.com/dsilibrary/showphoto.php?photo=19535&cat=all&limit=all Diana Luo, Hong Joo Kim, Carrie Yang

  13. SKELETAL TYPE • The interstitial fluid acts as a hydrostatic skeleton – flatworms change the shapes of the fluid-filled compartments to control their overall form and movement http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb5pg5.htm Diana Luo, Hong Joo Kim, Carrie Yang

  14. REPRODUCTION (METHODS, TYPES) • Triploblastic development (ectoderm, mesoderm, endoderm) • Planarians can reproduce asexually (through regeneration) or sexually • Tapeworms have proglottids that produce thousands of eggs • Copulating mates cross-fertilize http://www.tutorvista.com/content/science/science-ii/reproduction/asexual-reproduction.php Diana Luo, Hong Joo Kim, Carrie Yang

  15. GAS EXCHANGE (HOW, STRUCTURES) • Flat shape places all the cells close to surrounding water  gas exchange by diffusion • No organs are specialized for gas exchange Every cell is able to partake in gas exchange http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb5pg5.htm Diana Luo, Hong Joo Kim, Carrie Yang

  16. Thank you for listening! A QUIZ??

  17. QUIZ QUESTIONS • 1. While of the following have bilateral symmetry?a. Porifera (Sponges)b. Cnidaria (Jellyfish and Anemones)c. Platyhelminthes (Flatworms)d. Nematoda (Roundworms) • 2. What do Annelida (Segmented Worms) have that Platyhelminthes (Flatworms) do not have?a. Bilateral Symmetryb. Body Cavityc. Respiratory Systemd. Nervous System Diana Luo, Hong Joo Kim, Carrie Yang

  18. QUIZ QUESTIONS • 3. What do all of the following have in common: Platyhelminthes (Flatworms), Arthropoda (Insects and Arachnids), Mollusca (Snails, Clams, and Squids), and Echinodermata (Sea Stars and Sea Urchins)a. Segmentationb. Open Circulatory Systemc. Asexual Reproductiond. Organ System • 4. What is the main difference between Platyhelminthes (Flatworms) and Nematoda (Roundworms)?a. A respiratory systemb. Symmetryc. Digestive Systemd. Segmentation Diana Luo, Hong Joo Kim, Carrie Yang

  19. QUIZ ANSWERS • 1. C and D • Explanation: Porifera do not have symmetry and Cnidaria have radial symmetry. • 2. B • Explanation: Both have bilateral symmetry and nervous systems (although their nervous systems slightly differ). Neither has a respiratory system. • 3. D • Explanation: Only the Arthropoda have segmentation. Only Mollusca and Arthropoda have open circulatory systems. Mollusca and Arthropoda do not undergo asexual reproduction. • 4. C • Explanation: Platyhelminthes have gastrovascular cavities while Nematoda have a separate mouth and anus. Neither have a respiratory system or segmentation. Both have bilateral symmetry. Diana Luo, Hong Joo Kim, Carrie Yang

  20. Thank you for listening! • Interesting videos for further reference: • http://www.youtube.com/watch?v=mh2dTIRReXU • http://www.youtube.com/watch?v=ET1v9-65Jwk

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