Worms & Mollusks

1. Worms & Mollusks Mrs. Wetzel Biology

2. Review • 5 kingdoms • Prokaryotes * • Protista * • Fungi * • Plants * • Animals

3. Review • Animal Kingdom • Invertebrates • Porifera * • Cnidarians * • Worms • Molluska • Arthropods • Echinoderms

4. Review • Vertebrates • Fish • Amphibians • Reptiles • Mammals

6. Worms • Three Phyla of worms • Platyhelminthes • Flatworms • Nematoda • Round worms • Annelida • Segmented worms

7. Platyhelminthes • Flat worms • Flatworms are soft flattened worms that have tissues and internal organ systems. • They are the simplest animals to have three germ layers, bilateral symmetry and cephalization

8. Platyhelminthes • Examples of flatworms are • Planaria • Flukes • Tapeworms

9. Platyhelminthes • Respiration, circulation, excretion all depend on diffusion. • Flame cells are specialized to remove waste

10. Platyhelminthes • Response- • Platyhelminthes have a collection of nerve cells near the head called ganglion. They are not complex enough to be called a brain. • Eyespot is also found on flatworms. It is used for detecting light

11. Platyhelminthes • Movement- Flatworms move using cilia found on epidermal cells, or by twisting in the water

12. Platyhelminthes • Classification- • Turbellarians- free living in water • Bottom dwellers eat decaying material on the bottom • Most famous = planaria

13. Platyhelminthes • Classification • Trematodes- parasitic • Most famous = flukes

14. Fluke Life Cycle

15. Platyhelminthes/Flukes • Schistosomiasis- rampant in areas with poor sewage systems (pee/ poo where you drink/ bathe) • Schistosomiasis eggs accumulate in the blood vessels clogging heart & causing tissue decay • * Parasitic flat worms have a slightly thicker coating that protects them from being digested by their host= tegument

16. Schistosomiasis

17. Platyhelminthes • Classification- Cestoda aka Tapeworm • Live inside the intestine of the host • Attach with the scolex

19. Nematoda • Nematodes= Roundworms

20. Nematoda • Feeding- many are free living carnivores that can live in moist soil, some are marine

21. Nematoda • Respiration/ Circulation/ Excretion • There is NO internal transport system, they depend on diffusion for transporting cellular metabolic waste such as ammonia.

22. Nematoda • Response= Ganglia same as flatworms (platyhelminthes)

23. Nematoda • Reproduction= Sexual

24. Trichinosis Adult worms live and mate in the intestine of the host- eggs are released and burrow into the intestinal wall. The larva then travel into the bloodstream and organs causing pain. The life cycle is complete when something ingests the muscle infected with tissue infected with eggs

26. Filarial Worms • Elephantiasis is cause when a large number of filarial worms block the passage of fluids within the lymph vessels of a part of the body

28. Ascarid Worms • Ascaris matures in the intestine of the host reaching up to 50 cm. The Ascaris causes severe malnutrition in more than 1 billion people worldwide

29. Hookworms • Hookworms live in the soil and enter the body through an exposed foot. They then borrow into the bloodstream where they set up shop sucking the blood of their host causing weakness and poor growth

30. Phylum Annelida • Segmented worms • Animals with segmented bodies and a true coelom lined with mesoderm

31. Phylum Annelida • Feeding and digestion- feeding varies • Annelids pull food into the pharynx it is then stored in the crop then eventually pushed down into a gizzard where it is ground up and digested

32. Phylum Annelida • Annelids have a closed circulatory system! Blood is circulated through a series of blood vessels

33. Phylum Annelida • Respiration- Marine annelids breath through gills • Terrestrial annelids have very moist skin which allows for gas exchange on the epidermis.

35. Phylum Annelida • Excretion- • Solid waste is passed through the anus • Liquid waste is filtered from the blood by nephridia

36. Phylum annelida • Movement • Longitudinal Muscles & circulatory muscles contract alternately allowing the worm to move • Marine annelids have parapodia= paddles

37. Phylum Annelida • Reproduction • Sexual • Asexual • Hermaphrodites- worms rarely fertilize themselves. Usually two worms will attach at each others clitellum and drop off some sperm. When eggs are ready to be fertilized the stored sperm from the other worm will be used. The thicken clitellum will then slip off of the worms body with the fertilized eggs and create a cocoon

38. Phylum Annelida • Classification • Oligochaetes- earth worms • Hirudinea Leeches- external parasites • Polychaeta- marine worms

41. Phylum Molluska • One of the oldest and most diverse Phyla • Soft bodies animals with an internal or external shell

42. Phylum Molluska • Body Plan- usually soft bodies animals with an internal or external shell • Shell • Visceral Mass • Mantle Cavity • Foot • Molluska and annelids are closely related as their larva is similar

43. Phylum Molluska • Feeding- herbivores, carnivores, filter feeders, detritivores, parasites • Snails & Slugs eat using their radula – looks like a big tongue • Octopi can produce toxins to poison their prey and then pull them into their jaws using their tentacles

44. Phylum Molluska • Respiration- • Aquatic Mollusks breath using gills • Terrestrial animals breath through gas exchange over the mantle cavity

45. Phylum Molluska • Circulation- open circulatory system- organs are bathed with blood in sinuses

46. Phylum Molluska • Excretion- Nephridia removes ammonia

47. Phylum Molluska • Response- Varies greatly • Bivalves- pretty simple small ganglia • Gastropods- small antennae that can sense their environment • Cephalopods- Highly developed brain • Can remember things • Reward & Punishment

48. Phylum Molluska • Movement- varies

49. Phylumn Molluska • Reproduction- • Sexual • Asexual • Hermaphrodites

50. Phylum Molluska • Classification • Bivalves; Clams, mussels, oysters • Gastropods; Snails, slugs • Cephalopods; Octopus, squid, nautilus.