1. Modern Biology: Chapter 34 1 Flatworms, Roundworms, and Rotifers Chapter 34 688-700 http://www.microscopyu.com/moviegallery/pondscum/index.html http://my.hrw.com/index.jsp

2. Modern Biology: Chapter 34 2 Objectives 34.1 Summarize the distinguishing characteristics of flatworms Describe the anatomy of a planarian Compare free-living and parasitic flatworms Diagram the life cycle of a fluke Describe the life cycle of a tapeworm

3. Modern Biology: Chapter 34 3 P. Platyhelminthes flat worms The P. Platyhelminthes includes organisms called flatworms. Their bodies develop from three germ layers and are more complex than those of sponges, cnidarians, and ctenophores. Flatworms have bilaterally symmetrical bodies, with dorsal and ventral surfaces, right and left sides and anterior and posterior ends.

4. Modern Biology: Chapter 34 4 Structure and Function of Flatworms Simple Bilaterally symmetry Flat body Has 3 germ layers Acoelomates Gas exchange in skin (diffusion) Cephalization Free living Parasites (on or inside animals) Only one opening (mouth and anus) Freshwater or marine

5. Modern Biology: Chapter 34 5 Structure and Function of Flatworms 20000 species, 4 classes 1. c. Turbellarira 2. c. Trematoda 3. c. Monagenea 4. c. Cestoda

6. Modern Biology: Chapter 34 6 1. c. Turbellarira A. Digestion and Excretion in Planarians (Dugesia) 4500 species, Salt water and fresh water - scavengers of decaying plants and animals, small organisms Pharynx (throat) muscular tube that ingests food and sends food to the gastrovascular cavity  diffuses to other parts of the body Use flame cells (look like flickering candle flames) along with excretory tubules to remove excess water from hypotonic environments

7. Modern Biology: Chapter 34 7 1. c. Turbellarira B. Neural control in Planarians More complex than cnidarians Cerebral ganglia- simple brain, two clusters of nerve cells at the anterior end Sensory cells transmit to nerves Eyespot- near the cerebral ganglia, can sense the intensity and direction of light Can also respond to touch, water currents and chemical in the environment

8. Modern Biology: Chapter 34 8 1. c. Turbellarira C. Reproduction in Planarians Hermaphrodites Sexual reproduction- they simultaneously fetilize each other Eggs are in a capsules and stick to rocks (3wks to hatch) Can also reproduce asexually (summer) The worm will split in two- fission Worm can regenerate tail

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12. Modern Biology: Chapter 34 12 c. Trematoda and c. Monagenea Parasitic flukes (leaf-shaped flatworms) Parasite Endoparasites- live inside organism (blood, intestines, lungs, liver, other organs) Exctoparasites- external surfaces (fish and frogs)

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14. Modern Biology: Chapter 34 14 c. Trematoda and c. Monagenea structure of flukes Anterior suckers and ventral sucker Simple nervous system Tegument- outer covering made up of proteins and carbohydrates that is a defense mechanism Protects against digestive enzymes

15. Modern Biology: Chapter 34 15 c. Trematoda and c. Monagenea Reproduction and life cycle flukes Hermaphroditic Fertilized eggs are store in uterus May release tens of thousands at one time Have more than one host

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17. Modern Biology: Chapter 34 17 Schistosoma Primary host- adult parasite gets its nourishment, sexual reproduction occurs (humans blood vessels) Excreted in wastes  fresh water system Becomes a ciliated larva and will attach a snail  will mature and develop a tail  burrow into humans in water If eggs don’t leave---- can be fatal 200million people world wide http://www.dpd.cdc.gov/DPDx/HTML/Opisthorchiasis.asp?body=Frames/M- R/Opisthorchiasis/body_Opisthorchiasis_page1.htm

18. Modern Biology: Chapter 34 18 Schistosoma

19. Modern Biology: Chapter 34 19 c. Cestoda 5000 species of tapeworms Intestines of almost all vertebrates Eating raw or undercooked food containing eggs or larvae May cause digestion problems, weight loss, lack of energy, anemia, decrees in red blood cells

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21. Modern Biology: Chapter 34 21 c. Cestoda- Structure of Tapeworm Also have tegument Scolex- hooks and suckers to host Proglottids- long series of body sections Similar nervous/ excretory system to other flatworms Lack eyespots/ other light sensing organs No mouth, gastrovascular cavity, digestive organs Get nutrients by absorbing directly from host digestive track

22. Modern Biology: Chapter 34 22 c. Cestoda- Reproduction and life cycle of Tapeworm Hermaphrodites 1000000 or more eggs in the proglottid Tanenia saginatus- Has two host (human and cow) Cysts- dormant larvae

23. Modern Biology: Chapter 34 23 34.2 Objectives Describe the body plan of a nematode Outline the relationship between humans and parasitic roundworms Describe the anatomy of a rotifer

24. Modern Biology: Chapter 34 24 P. Nematoda and P. Rotifera Members of the phyla Nematoda and rotifera have bilaterally symmetrical bodies that contain a fluid-filled space. This space holds the internal organs and serves as a storage area for eggs and sperm. It also supports the body and provides a structure against which the muscles can contract.

25. Modern Biology: Chapter 34 25 P. Nematoda (roundworms) 15000 knows species, estimated 500,000 Long slender bodies that taper at ends Pseudocoelomates 1mm to 120 cm Have a complete digestive tract (mouth-gut – anus) Separate sexes Fresh and salt water, land Can be parasites of plants and animals http://www.microscopyu.com/moviegallery/pondscum/nematode/ind ex.htmlhttp://www.microscopyu.com/moviegallery/pondscum/nematode/ind ex.html

26. Modern Biology: Chapter 34 26 Ascaris Live in pig, horse, humans intestines Feed on food from host Can block hosts intestines 30cm long (1ft) 200,000 eggs every day, leave body in feces Can live in soil for years Contaminated food and water Larvae bore into bloodstream  lungs and throat  to intestines Colonoscopy Demonstrating a Moving Worm http://www.youtube.com/watch?v=HOaZCkA8Zv k http://www.youtube.com/watch?v=HOaZCkA8Zv k

27. Modern Biology: Chapter 34 27 Phylum Nematoda Ascaris worms

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30. Modern Biology: Chapter 34 30 Hookworms Parasite (tropical and subtropical regions) Mouth has cutting plates hook on intestinal wall Can cause anemia Can cause slow mental development in children Larva live in soil  boring through host’s feet  travel to intestines Infect 1 billion people a year

31. Modern Biology: Chapter 34 31 Trichinella Infect human, pigs and other mammals Eating undercooked meat Live in walls of host intestines Larvae are in cysts Causes Trichinosis, muscle pain and stiffness Cook and freeze at high temps to kill worms

32. Modern Biology: Chapter 34 32 Other Parasitic roundworms pinworm, Enterobius Most common 50% in some areas Not serious 5-10mm, look like threads Live in lower region of intestines/ anus At night female exists and lays eggs Person scratches during sleep can be passed on to other persons Eggs must be ingested and will hatch in intestine

33. Modern Biology: Chapter 34 33 Other Parasitic roundworms Filarial worms- Infect over 250 million in tropical countries Live in lymphatic system 100mm or 4in Enter blood passed by mosquitoes Causes swollen limbs and the skin hardens and thickens  elephantiasis Toxocara or T. cati- heart worms of dogs and cats

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35. Modern Biology: Chapter 34 35 P. Rotifera- rotifers Pseudocoelomates 1750 species Transparent Free-living in fresh water, Can live without water long periods 100 to 500 um – males smaller Multicellular and specialized organs Cilia around mouth Parthenogenesis- unfertilized eggs develop into adult females other produce 2 types of eggs, one is the sperm that will fertilize egg

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37. Ascaris Dissection http://www.youtube.com/watch?v=_ybbnPj 0t9Y&feature=PlayList&p=E0DC6AAA94A FE60F&playnext_from=PL&playnext=1&in dex=8http://www.youtube.com/watch?v=_ybbnPj 0t9Y&feature=PlayList&p=E0DC6AAA94A FE60F&playnext_from=PL&playnext=1&in dex=8 Modern Biology: Chapter 34 37