1. Flatworms:
Planarians, Flukes, and
Tapeworms

2. Flatworm Facts:

3. Flatworm Facts:
• Simplest group of worms

4. Flatworm Facts:
• Simplest group of worms
• Symmetry?
– Bilateral

5. Flatworm Facts:
• Simplest group of worms
• Symmetry?
– Bilateral
• Head

6. Flatworm Facts:
• Simplest group of worms
• Symmetry?
– Bilateral
• Head
• No anus

7. Planarian Facts:

8. Planarian Facts:
• Smaller than length of fingernail

9. Planarian Facts:
• Smaller than length of fingernail
• Have eyespots and sensory lobes

10. Planarian Facts:
• Smaller than length of fingernail
• Have eyespots and sensory lobes
• Live in water and on land

11. Planarian Facts:
• Smaller than length of fingernail
• Have eyespots and sensory lobes
• Live in water and on land
• Predators: eat other animals or parts of
animals

12. Planarian Facts:
• Smaller than length of fingernail
• Have eyespots and sensory lobes
• Live in water and on land
• Predators: eat other animals or parts of
animals
• Pharynx pulls food into gut to be digested

25. Flukes and Tapeworms

26. Flukes and Tapeworms
• All are parasites
– Parasite is an organism that feeds on a host.
• Host is usually not killed

27. Flukes and Tapeworms
• All are parasites
– Parasite is an organism that feeds on a host.
• Host is usually not killed
• Most live inside other animals

28. Flukes and Tapeworms
• All are parasites
– Parasite is an organism that feeds on a host.
• Host is usually not killed
• Most live inside other animals
• Eggs pass out of host with host’s waste

29. Flukes and Tapeworms
• All are parasites
– Parasite is an organism that feeds on a host.
• Host is usually not killed
• Most live inside other animals
• Eggs pass out of host with host’s waste
• If eggs end up in drinking water or on
food, they can be eaten by another host.

30. Body Parts

31. Body Parts
• Tiny heads, no eyespots or sensory lobes

32. Body Parts
• Tiny heads, no eyespots or sensory lobes
• Special suckers and hooks for attaching to
host

33. Body Parts
• Tiny heads, no eyespots or sensory lobes
• Special suckers and hooks for attaching to
host
• Some have special skin so they are not
broken down by stomach acids

34. Body Parts
• Tiny heads, no eyespots or sensory lobes
• Special suckers and hooks for attaching to
host
• Some have special skin so they are not
broken down by stomach acids
• Tapeworms don’t have a gut
– Absorb nutrients right from intestines of host

35. Sheep Liver Fluke

36. Sheep Liver Fluke

37. Intestinal blood fluke

38. Intestinal blood fluke

39. Flukes in swim bladder of eel

40. Flukes in swim bladder of eel

41. Cat Tapeworm

42. Cat Tapeworm

43. Tapeworm found in fish—new
contraceptive??

44. Tapeworm found in fish—new
contraceptive??

45. Tapeworm that can infest humans

46. Tapeworm that can infest humans

48. • Can
grow
up to
15m

49. • Can
grow
up to
15m
• Stays
as a
cyst in
pork

50. Pork tapeworm pulled out of a
human

51. Pork tapeworm pulled out of a
human

63. Attachment organ of tapeworm

64. Attachment organ of tapeworm

65. Roundworms

66. Roundworms
• Round, when viewed in cross section

67. Roundworms
• Round, when viewed in cross section
• Bilateral Symmetry

68. Roundworms
• Round, when viewed in cross section
• Bilateral Symmetry
• Very small
– 1 rotten apple 100,000 roundworms!

69. Roundworms
• Round, when viewed in cross section
• Bilateral Symmetry
• Very small
– 1 rotten apple 100,000 roundworms!
• Primitive brain and nerve cords

70. Roundworms
• Round, when viewed in cross section
• Bilateral Symmetry
• Very small
– 1 rotten apple 100,000 roundworms!
• Primitive brain and nerve cords
• Most are parasites
– Humans pinworms and hookworms,
trichinosis

71. Parasitic roundworm from sea lion

72. Parasitic roundworm from sea lion

74. • Roundworms
extracted from
a Kenyan child

77. Cat and dog hookworms—you can
pick up the eggs by walking
barefoot

78. Cat and dog hookworms—you can
pick up the eggs by walking
barefoot