1. 1 Phylum Platyhelminthes April Adams Zoology NCHS

2. 2 Phylum Platyhelminthes Flat worms Triploblastic= 3 germ layers Acoelomate Bilateral symmetry Hermaphroditic 1 opening for digestion Simple nervous and muscular systems Flame cells May be free living or parasitic CEPHALIZATION

3. 3 Acoelomate EctodermMesodermEndoderm Digestive cavity is the only inner cavity, and is not lined with mesoderm.

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5. 5 Phylum Platyhelminthes: Class Turbellaria Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Acoelomate

6. 6 Other Body Plans: Pseudocoelomate EctodermMesodermEndoderm Fluid filled cavity between the endoderm and ectoderm- pseudocoelom Differs from a true coelom because…. It is not entirely lined with mesoderm tissue Organs are not suspended or attached to membranes (mesenteries)

7. 7 Other Body Plans: Coelomate EctodermMesodermEndoderm Mesoderm lines cavity between digestive tract and body wall

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9. Flatworm Body Systems No Circulatory or Respiratory systems- simple diffusion through body wall Systems Present- Digestive Nervous Reproductive Excretory 9

10. Flatworm Body Systems: Digestive Incomplete- mouth pharynx (to swallow food) Gastrovascular cavity intestine(no anus) 10

11. 11 Nervous System Lateral nerve cord Eye spot= detects light anterior ganglia transverse nerve cord sensory receptors

12. 12 Cephalization=“Primitive Brain” Auricle Cerebralganglion Paired nerve cords

13. 13 Excretory System Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. -Gets rid of nitrogenous wastes - protonephridia- first kidney Components: -Flame cells -Excretory ducts/tubes -pores

14. 14 Reproductive System Sexual and asexual reproduction sexual- eggs + sperm asexual- regeneration Hermaphrodites- both male (penis and testis) and female organs(vagina and ovary)

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16. Checkpoint 16 1.Which phylum do flatworms belong to? 2.Flatworms are triploblastic, what does that mean? 3.What type of body cavity do they have? Explain. 4.Flatworms are the “first” of many things in the animal kingdom. What traits do flatworms display that were not present in Poriferans, Cnidarians, or Ctenophores? 5.Flatworms have the first excretory system. How does it work?

17. Kingdom Animalia Phylum Platyhelminthes Classes: Turbellaria Trematoda Cestoda 17

18. 18 Class Turbellaria Most free-living Aquatic Eye spots Regenerate if cut in two Ex. Planaria

19. Planarians Lives in fresh water usually under leaves and rocks Usually feeds on dead or slow moving organisms

20. Planarian Reproduction Reproduction: Sexually: hermaphrodites Asexually: can regenerate missing body parts (called fission) What would happen ???? Detaches its tail end and each half regrows the lost parts each Planaria gives and receives sperm

21. Planarians: body structures Nervous/sensory system: Brain-like structure Nerve cord: carries impulses down body Eyespots: sense light and dark Sensory pits: line sides of head to aid in movement and sensing surroundings

22. Planarians: body structures Digestive/excretory system Mouth: located in center of ventral side Pharynx: tube like structure which extends from mouth during feeding; acts like a straw sucking up food and carrying it to body Food enters mouth and solid wastes exit mouth Flame Cells: remove excess water and nitrogenous wastes eyespot ganglion Gastrovascular cavity Mouth pharynx Flame cells ganglion Nerve cord (15:00 Sea of Life- Planarian clip)

23. 23 Class Trematoda Trema= “hole” Holdfast devices –Endoparasites Complex life cycle- larval stage in one or more hosts Primary host-juvenile/larva stage- Secondary host- adult stage Ex. Blood and liver flukes

24. Flukes Blood fluke life cycle: Eggs are released in water from wastes of infected host Hatch in to swimming larvae in water Larvae enter a primary host (like a snail) where they develop & mature to Cercaria stage Enter water again and bore into skin of secondary host (man) From the blood stream they bore into intestines where they attach and feed on blood

25. 25 Schistosoma Blood flukes 200 million people 1 million deaths/year

26. 26 Life Cycle of a Schistosome Fluke Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

27. 27 Schistosome Cercaria have forked tail

28. 28 Swimmers Itch

29. 29 Clonorchis sinensis Oral suckerIntestineUterusYolk gland TestesOvarySeminal recepticle

30. 30 Clonorchis sinensis Chinese liver fluke 50 million people Cirrhosis of liver Diarrhea Edema Pain

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32. 32 Fasciola hepatica Sheep liver fluke Sheep, cattle and man –Weight loss Eat contaminated vegetation

33. 33 Life Cycle of the Sheep Liver Fluke Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

34. 34 Paragonimus westermani Lung fluke Carnivores, pigs, rodents and man May be fatal

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37. 37 Class Cestoda: “cess pool” Tape worms All parasitic Live in intestines of vertebrates No digestive system 40 feet long

38. Tapeworm structures Scolex= “head” hooks and suckers to aid in attachment to intestine Proglottids: individual parts of worm- reproductive –Each one is detachable –Each proglottid may contain up to 100,000 eggs which fall off when full –When released, they exit with the host’s wastes gonad

39. Tapeworm life cycle Cows consume contaminated vegetation, Eggs hatch in intestines of intermediate host (pig or cow) Young worms burrow out of intestine into cow’s muscle tissue forming cysts Secondary host (man) eats undercooked/raw meat containing worm larvae cysts Larvae hatch and mature in intestines, soak up digested food of host Proglottids mature, eggs released with feces Eggs attach to plant to form cysts

40. 40 Scolex

41. 41 Proglottid Uterus Testes Ovary Yolk gland Vas deferens Seminal receptacle

42. 42 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pork Tapeworm (Taenia solium)

43. 43 Taenia saginata

44. 44 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Source: Redrawn From Centers for Disease Control, Atlanta, GA. Life Cycle of the Broad Fish Tapeworm Diphyllobothrium latum

45. 45 Dipylidium caninum

46. 46 Echinococcus granulosus Parasite of dogs –Host Juveniles in sheep, man and other mammals –Intermediate host Hydatid cyst

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48. 48 Hydatid Cyst Cysticercus –Juvenile stage

49. 49 Adult stage in dog Ecinococcus granulosus

50. Checkpoint 1.What are the three classes of flatworms? 2.Which class contains free living species? 3.How do planarians consume food? 4.How are flukes different from Planarians? 5.How are tapeworms different from Trematodes? 50

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