1. WORMS – Chapter 27

2. A) Flatworms: Phylum Platyhelminthes Soft and Flat Tissues and Internal Organ Systems 3 embryonic germ layers Bilateral symmetry Cephalization Acoelomates-without coelom (no fluid- filled body cavity)

3. Feeding Food enters Mouth/anus, then travels to pharynx, then to Gastrovascular cavity for digestion/absorption Carnivore Scavenger Parasitic

4. Respiration, Circulation, Excretion Diffusion of O 2 and nutrients through body walls Flame cells/Nephridia – remove excess water and metabolic waste Connected to pores in the skin

5. Response Ganglia – controls N.S. (nerve cell cluster) Eyespot – detects light changes Some have specialized cells to detect chemicals, food, etc.

6. Movement Cilia on epidermal cells for gliding Muscle cells for twisting/turning

7. Reproduction Hermaphrodites Sexual by 2 worms exchanging sperm, and each lay eggs Internal fertilization Asexual by fission (organism splits in 2 and each half grows new parts)

8. Classes of Flatworms: Turbellaria (ex: planarian) Trematoda (ex:Flukes) Cestoda (ex: Tapeworms)

10. A1) Class Turbellaria: Turbellarians Free-living Marine or fresh water Not Parasitic

11. Ex. Pseudobiceros gloriosus Tropical free-living flatworm (non-parasitic)

12. Ex. Planaria Cross-eyed; fresh water free-living flatworm (non-parasitic)

13. A2) Class Trematoda: Flukes Parasitic Infect internal organs of hosts Intestines; blood vessels Some have Multiple Hosts Snails as intermediate hosts

14. Ex. Blood Fluke (not free-living) Parasite that matures in human blood vessels

15. Schistosoma mansoni Life Cycle Blood Fluke (has multiple hosts: Snail=intermediate host Human=primary host)

16. A3) Class Cestoda: Tapeworms Parasitic Lives in intestines Long and flat Scolex-head with suckers (hooks) Proglottids-body segments

17. 1) Cow/Fish/Pig (intermediate host) consumes food or water w/ zygotes (fecally contaminated) 2) Hatch to larvae and burrow into muscles as cysts (protected) 3) Human eats meat not fully cooked and larvae activated to grow to adult in human intestines 4) Eggs passed in human feces Tapeworm Life Cycle

18. B) Roundworms: Phylum Nematoda Unsegmented Most are free-living Digestive tract with two openings – mouth and anus Pseudocoelom-false body cavity

19. Feeding Most are carnivores Use mouth parts and spines to catch food Hook Worms

20. Respiration, Circulation, Excretion Diffusion through body walls

21. Response Simple nervous system Nerves run body length from Ganglia in head Simple sense organs to detect chemicals from prey or hosts

22. Movement Hydrostatic skeleton Muscles and fluid in the pseudocoelom work together to produce movement

23. Reproduction Sexual Internal fertilization Separate genders

24. Human Disease --Parasitic Roundworms Trichinosis-Causing Worms Filarial Worms Ascarid Worms Hookworms

25. B1) Trichinella  Trichinosis Cysts are ingested from eating animal muscle tissue Females burrow into intestinal wall Larvae travel to organs via bloodstream and form cysts 2 common hosts Rats and pigs Humans affected by eating undercooked pork

26. B2) Filarial Worms Live in blood and lymph vessels Transmitted by mosquitoes Can block the movement of fluids Elephantiasis

27. B3) Ascaris 1. Eggs hatch in intestines 2. Larvae burrow into bloodstream to lungs 3. Travel to air passages, coughed up and then swallowed 4. Carried to the intestines and mature 5. Eggs released via feces Spread by eating improperly washed vegetables (foods)

28. Male vs. Female

29. B4) Hookworms ¼ of the human population infected with hookworms Eggs hatch outside body and develop in soil Use sharp toothlike plates and hooks to burrow into skin and enter bloodstream Travel to lungs and then intestines Suck blood causing weakness Don’t walk barefoot outside!!!

31. --Segmented worms with a coelom (body cavity) that is lined with mesoderm C) Annelids: Phylum Annelida

32. Feeding and digestion Filter feeders to predators Earthworm Full Digestive Tract: mouth  pharynx  esophagus  crop  gizzard  intestine  anus Crop- store food Gizzard- grind food Anus – removal of solid undigested waste

33. Circulation Closed system, 2 major blood vessels Dorsal blood vessel: tail  head (pumps like heart) Ventral blood vessel: head  tail Response Ganglia Ventral nerve cord

34. Respiration and Excretion Respiration- Skin (moist due to mucus secretion) - land Gills - aquatic Excretion- Nephridia - filter out fluid/liquid metabolic waste

35. Movement- Hydrostatic skeleton Longitudinal muscles – short and fat Circular muscles – long and thin Setae- brush hair-like projections Reproduction- Mostly sexual, some hermaphrodites, some separate sexes Clitellum-thick band secretes mucus ring after 2 worms exchange sperm for fertilization Mucus ring slips off and forms protective cocoon  hatching

37. Classes of Annelids

38. C1) Class Oligochaeta: Oligochaetes- Earthworms Few setae on each segment Soil or fresh water

39. C2) Class Hirudinea: Leeches External parasites Suck blood and body fluids of host Medicinal Uses Reduces swelling and prevents clotting

40. C3) Class Polychaeta: Polychaetes Sandworms, bloodworms Marine Paired paddle-like appendages w/ setae Live in coral reefs, sand, mud

41. What do you think caused this marking? Worm? Bacteria? Virus? Fungus? Hickey?

42. Ringworm Not caused by a worm! Fungal infection Can occur on any part of body Contact with infected people, animals, soil, etc. Medically called Tinea

43. Ecology of Annelids Burrowing through soil builds tunnels for plants roots and water Help plant matter decompose as they digest the soil “mine” minerals from deep soil layers Earthworm castings are rich in N, P, K, and bacteria Food for birds

44. Earthworm Dissection

45. External View

46. Internal Structure

47. Pharynx

48. Aortic Arches

49. Seminal Vesicle

50. Seminal Receptacle

51. Septum

52. Crop

53. Gizzard

54. Intestine

55. Ventral Nerve Cord

56. Dorsal Blood Vessel