Biol 11 Lesson 4 Feb 9 - Ch. 26 Flatworms

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Biology 11
Animal Biology unit - Invertebrates
Miller, K.R. & Levine, J. (2000). Biology (5th ed.). New Jersey: Prentice Hall.
Ch. 26: Sponges, Cnidarians, and Unsegmented Worms
pp. 570-575.

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Biol 11 Lesson 4 Feb 9 - Ch. 26 Flatworms

  1. 1. Homework from last class: <ul><li>Complete Section Review 26-3 questions 1-5 (p. 569) </li></ul><ul><li>Complete Cnidaria crossword puzzle </li></ul><ul><li>Label and colour Cnidaria diagram handout — I will provide you with a new handout (due Tues, Feb. 15) </li></ul><ul><li>Read over class notes and check out the class blog: </li></ul><ul><li>http://msoonscience.blogspot.com/ </li></ul><ul><li>Study for Quiz on Phylum Cnidaria next class! </li></ul>
  2. 2. Cnidaria quiz <ul><li>You have 10 minutes to write the quiz. </li></ul><ul><li>Good luck! </li></ul>
  3. 3. Section Review 26-3 (p. 569): <ul><li>What is a cnidarian? What kind of symmetry do cnidarians have? </li></ul><ul><li>A cnidarian is a soft-bodied aquatic animal exhibiting radial symmetry that has stinging tentacles containing nematocysts. </li></ul>
  4. 4. Section Review 26-2 (p. 563): <ul><li>2) Give an example of each class of cnidarians. </li></ul><ul><li>1) Class Hydrozoa: hydra, Portuguese man-of-war </li></ul><ul><li>2) Class Scyphozoa: jellyfish </li></ul><ul><li>3) Class Anthozoa: sea anemone, coral </li></ul>E.g. Hydra E.g. jellyfish E.g. Sea anemones and coral
  5. 5. Section Review 26-3 (p. 569): <ul><li>Describe the life cycle of a typical cnidarian. </li></ul><ul><li>A fertilized egg develops into a ciliated larva </li></ul><ul><li>The larva develops into a polyp </li></ul><ul><li>The polyp produces medusae asexually by budding </li></ul><ul><li>Eggs from female medusae are fertilized by sperms from male medusae </li></ul>1 2 3 4
  6. 6. Section Review 26-3 (p. 569): <ul><li>Discuss symbiotic relationships and other interactions between cnidarians and other living things. </li></ul><ul><li>Anthozoans provide habitat for photosynthetic protists or bacteria; they in turn provide food for the anthozoan. </li></ul><ul><li>Sea anemones and small fish are symbiotic. </li></ul><ul><li>Coral reefs provide a home </li></ul><ul><li>for many animals and help </li></ul><ul><li>protect shore habitats from </li></ul><ul><li>erosion. </li></ul>
  7. 7. Section Review 26-3 (p. 569): <ul><li>A medusa usually has specialized sense organs. It may also have nerves that are organized into rings that encircle its body and structures that control body contractions. Explain why a medusa needs a more complex nervous system than a polyp. </li></ul><ul><li>( Hint: How does the lifestyle of a medusa differ from that of a polyp?) </li></ul><ul><li>Medusae are motile and thus need a nervous </li></ul><ul><li>system that can coordinate movement </li></ul><ul><li>and respond to stimuli quickly and effectively. </li></ul>
  8. 8. Introduction to Planaria <ul><li>http://www.youtube.com/watch?v=w0QzSYQGsnA </li></ul>
  9. 9. Phylum Platyhelminthes: Flatworms Chapter 26: Sponges, Cnidarians, and Unsegmented Worms pp. 570-575
  10. 10. Introduction to Flatworms <ul><li>Phylum Platyhelminthes: platy = flat, helminth = worm </li></ul><ul><li>Simplest animals with bilateral symmetry </li></ul><ul><li>Body has 3 cell layers </li></ul><ul><ul><li>ectoderm (outer) </li></ul></ul><ul><ul><li>mesoderm (middle) </li></ul></ul><ul><ul><li>endoderm (inner) </li></ul></ul><ul><li>Show the beginnings of cephalization (i.e. a head) </li></ul><ul><li>Can be free-living or parasitic </li></ul>ectoderm mesoderm endoderm gastrovascular cavity
  11. 11. Classes of Flatworms <ul><li>Class Turbellaria </li></ul><ul><ul><li>Free-living, usually small, freshwater </li></ul></ul><ul><ul><li>Predators or scavengers </li></ul></ul><ul><ul><li>Example member: Planaria </li></ul></ul>
  12. 12. Classes of Flatworms <ul><ul><ul><li>2) Class Trematoda (flukes) </li></ul></ul></ul><ul><ul><li>Parasitic (internal parasites)  often infect blood and organs </li></ul></ul><ul><ul><li>Often have more than 1 host </li></ul></ul><ul><ul><li>Reduced digestive and nervous systems </li></ul></ul><ul><ul><li>Example member: blood flukes ( Schistosoma) ; </li></ul></ul><ul><ul><li>has 2 hosts (p. 573) </li></ul></ul><ul><ul><ul><li>humans = primary host </li></ul></ul></ul><ul><ul><ul><li>snails = intermediate host </li></ul></ul></ul>
  13. 13. Class Trematoda - blood fluke Schistosoma Intermediate host: snail primary host: human p. 573
  14. 14. Classes of Flatworms <ul><ul><ul><li>3) Class Cestoda (tapeworms) </li></ul></ul></ul><ul><ul><ul><ul><ul><li>Long and flat parasites </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Head is called scolex </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Narrow neck region that divides to form proglottids (contain huge numbers of sperm and eggs)  p. 575 (beef tapeworm) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>No digestive or nervous systems </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Highly developed reproductive </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>system </li></ul></ul></ul></ul></ul>proglottid scolex
  15. 15. Form and Function of Flatworms <ul><ul><ul><li>Digestive system: </li></ul></ul></ul><ul><ul><ul><li>Gastrovascular cavity where food is broken down </li></ul></ul></ul><ul><ul><ul><li>Two-way digestive system </li></ul></ul></ul><ul><ul><ul><li>Food and wastes enter/exit the pharynx </li></ul></ul></ul>Pharynx = opening to the gastrovascular cavity e.g.Planaria
  16. 16. <ul><ul><ul><li>Respiratory system: </li></ul></ul></ul><ul><ul><ul><li>Circulatory system: </li></ul></ul></ul><ul><ul><ul><li>Excretory system: </li></ul></ul></ul><ul><ul><ul><li>Flame cells - primitive excretory structures that get rid of excess water </li></ul></ul></ul><ul><ul><ul><li>Metabolic wastes diffuse through the skin </li></ul></ul></ul><ul><li>No organized systems for these </li></ul><ul><li>O 2 , CO 2 diffuse through the ectoderm </li></ul>
  17. 17. <ul><ul><ul><ul><li>Nervous system: </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Fairly well-developed </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Has primitive “brain” and </li></ul></ul></ul></ul><ul><ul><ul><ul><li>2 ventral nerve cords </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Ocelli (aka eyespots ) to </li></ul></ul></ul></ul><ul><ul><ul><ul><li>detect light/dark </li></ul></ul></ul></ul><ul><ul><ul><li>Two auricles sensitive to touch </li></ul></ul></ul><ul><ul><ul><li>and chemicals </li></ul></ul></ul><ul><ul><ul><li>Musculoskeletal system: </li></ul></ul></ul><ul><ul><ul><li>Muscles and cilia on ventral surface for locomotion </li></ul></ul></ul>Planaria nervous system auricle
  18. 18. If you cut a part off, it grows into a new worm!
  19. 19. Planaria reproductive system
  20. 20. La fin! Activity: Phylum Platyhelminthes Question Worksheet Phylum Platyhelminthes Colouring/Labeling Worksheet New Phylum Cnidaria Colouring/Labeling Worksheet
  21. 21. Activity: <ul><li>Work on the Platyhelminthes question worksheet </li></ul><ul><li>Work on the Platyhelminthes labeling/colouring worksheet </li></ul><ul><ul><li>Make a legend of the colours you use on your diagram </li></ul></ul><ul><ul><li>e.g. Digestive system </li></ul></ul><ul><ul><li>Respiratory system </li></ul></ul><ul><li>3) Work on the new Phylum Cnidaria labeling/colouring worksheet. </li></ul>
  22. 22. Homework for next class: <ul><li>Complete the Platyhelminthes question worksheet </li></ul><ul><li>Complete the Platyhelminthes labeling/colouring worksheet </li></ul><ul><li>Complete the new Cnidaria labeling/colouring worksheet </li></ul><ul><li>Read over class notes and check out the class blog: </li></ul><ul><li>http://msoonscience.blogspot.com/ </li></ul><ul><li>Study for Quiz on Phylum Platyhelminthes next class! </li></ul>

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