2. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu To View the presentation as a slideshow with effects select “View” on the menu bar and click on “Slide Show.” To advance through the presentation, click the right-arrow key or the space bar. From the resources slide, click on any resource to see a presentation for that resource. From the Chapter menu screen click on any lesson to go directly to that lesson’s presentation. You may exit the slide show at any time by pressing the Esc key. How to Use This Presentation

3. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter Presentation TransparenciesStandardized Test Prep Visual Concepts Resources

4. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Flatworms, Roundworms, and Rotifers Chapter 34 Table of Contents Section 1 Platyhelminthes Section 2 Nematoda and Rotifera

5. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Platyhelminthes Chapter 34 Objectives 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.

6. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Platyhelminthes Chapter 34 Structure and Function of Flatworms The phylum Platyhelminthes includes organisms called flatworms. They are more complex than sponges but are the simplest animals with bilateral symmetry. Their bodies develop from three germ layers: –ectoderm –mesoderm –endoderm They are acoelomates with dorsoventrally flattened bodies. They exhibit cephalization. The classification of Platyhelminthes has undergone many recent changes.

7. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 34 Characteristics of Flatworms Section 1 Platyhelminthes

8. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Platyhelminthes Chapter 34 Class Turbellaria The majority of species in the class Turbellaria live in the ocean. The most familiar turbellarians are the freshwater planarians of the genus Dugesia. Planarians have a spade-shaped anterior end and a tapered posterior end.

9. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Platyhelminthes Chapter 34 Class Turbellaria, continued Digestion and Excretion in Planarians Planarians feed on decaying plant or animal matter and smaller organisms. Food is ingested through the pharynx. Planarians eliminate excess water through a network of excretory tubules. –Each tubule is connected to several flame cells. –The water is transported through the tubules and excreted from pores on the body surface.

10. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Platyhelminthes Chapter 34 Class Turbellaria, continued Neural Control in Planarians The planarian nervous system is more complex than the nerve net of cnidarians. The cerebral ganglia serve as a simple brain. A planarian’s nervous system gives it the ability to learn. Planarians sense light with eyespots. Other sensory cells respond to touch, water currents, and chemicals in the environment.

11. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Platyhelminthes Chapter 34 Class Turbellaria, continued Reproduction in Planarians Planarians are hermaphrodites that can reproduce sexually or asexually. Their eggs are laid in capsules. During asexual reproduction, their body undergoes fission and the two halves regenerate missing parts.

12. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 34 Planarian Section 1 Platyhelminthes

13. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 34 Anatomy of a Planarian Section 1 Platyhelminthes

14. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 34 Exploration of a Flatworm Section 1 Platyhelminthes

15. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 34 Development of Flatworm Embryo Section 1 Platyhelminthes

16. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Platyhelminthes Chapter 34 Classes Trematoda and Monogenea The classes Trematoda and Monogenea consist of parasitic flukes. Some are endoparasites; others are ectoparasites. Structure of Flukes A fluke clings to the tissues of its host by an anterior sucker and a ventral sucker. A fluke’s nervous system is similar to a planarian’s, but simpler. The external surface of a fluke is covered by a protective layer called the tegument.

17. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 34 Tegument Section 1 Platyhelminthes

18. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Platyhelminthes Chapter 34 Classes Trematoda and Monogenea, continued Reproduction and Life Cycle of Flukes Most flukes have highly developed reproductive systems and are hermaphroditic. Fertilized eggs are stored in a fluke’s uterus until they are ready to be released. Flukes have complicated life cycles that involve more than one host species. For example, the trematode blood flukes of the genus Schistosoma use humans as a primary hosts and snails as intermediate hosts. They can cause schistosomiasis.

19. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 34 Life Cycle of Schistosoma Section 1 Platyhelminthes

20. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 34 Life Cycle of Flukes Section 1 Platyhelminthes

21. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Platyhelminthes Chapter 34 Class Cestoda About 5,000 species of tapeworms make up the class Cestoda. Tapeworms can live in the intestines of almost all vertebrates. Structure of Tapeworms Tapeworms are surrounded by a tegument. They attach to the host with a scolex. The body is a series of many sections called proglottids. Tapeworms have no light-sensing organs, no mouth, no gastrovascular cavity, and no digestive organs.

22. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 34 Anatomy of a Tapeworm Section 1 Platyhelminthes

23. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Platyhelminthes Chapter 34 Class Cestoda, continued Reproduction and Life Cycle of Tapeworms Nearly all tapeworms are hermaphrodites. Each proglottid contains male and female reproductive organs and little else. New proglottids are added to the front of the tapeworm. Older proglottids grow, mature, and begin producing eggs. Eggs in one proglottid are usually fertilized by sperm from a different proglottid, possibly a different individual. An example is the beef tapeworm, Taenia saginatus. Its primary host is a human and its intermediate host is a cow. Its larvae form cysts in the muscle tissue of the cow.

24. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 34 Life Cycle of Beef Tapeworm Section 1 Platyhelminthes

25. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 34 Life Cycle of Tapeworms Section 1 Platyhelminthes

26. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Nematoda and Rotifera Chapter 34 Objectives Describe the body plan of a nematode. Outline the relationship between humans and parasitic roundworms. Describe the anatomy of a rotifer.

27. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Nematoda and Rotifera Chapter 34 Phylum Nematoda The phylum Nematoda is made up of roundworms with long, slender bodies that taper at both ends. Roundworms are among several phyla of pseudocoelomates. Roundworms have a digestive tract with two openings. Most roundworms have separate sexes and are covered by a protective cuticle. Most species are free-living; some are parasites.

28. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Nematoda and Rotifera Chapter 34 Phylum Nematoda, continued Ascaris The genus Ascaris infects pigs, horses, and humans. The eggs enter hosts through contaminated food or water, develop into larvae in the intestines, and can infect the lungs. The eggs are spread in the hosts’ feces. Hookworms Hookworms are intestinal parasites that feed on blood. The eggs produce larvae in soil, and the larvae enter hosts through the feet. Hookworms infect about one billion people worldwide.

29. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Nematoda and Rotifera Chapter 34 Phylum Nematoda, continued Trichinella The genus Trichinella infects humans and other mammals. Adults live in intestines and larvae form cysts in muscles. People usually become infected from undercooked pork. Infection causes the disease trichinosis. Other Parasitic Roundworms Pinworms, genus Enterobius, are common parasites of humans. They do not cause any serious disease. Filarial worms infect many people in tropical countries. The most dangerous ones infect the lymphatic system and may cause elephantiasis.

30. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 34 Exploration of a Roundworm Section 2 Nematoda and Rotifera

31. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Nematoda and Rotifera Chapter 34 Phylum Rotifera Members of the phylum Rotifera are called rotifers. Most rotifers are tiny, transparent, free-living animals that live in fresh water. Some can survive without water for long periods. Although tiny, they are truly multicellular and have specialized organ systems. They use the crown of cilia around their mouth to sweep food into the mastax. The digestive, reproductive, and excretory systems empty into the cloaca. Some species reproduce by parthenogenesis.

32. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice 1. What does a planarian use its pharynx for? A. feeding B. movement C. reproduction D. to respond to light Standardized Test Prep Chapter 34

33. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 1. What does a planarian use its pharynx for? A. feeding B. movement C. reproduction D. to respond to light Standardized Test Prep Chapter 34

34. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 2. Where do blood flukes of the genus Schistosoma reproduce asexually? F. in water G. inside a snail H. inside a cow’s intestine J. inside a human’s blood vessels Standardized Test Prep Chapter 34

35. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 2. Where do blood flukes of the genus Schistosoma reproduce asexually? F. in water G. inside a snail H. inside a cow’s intestine J. inside a human’s blood vessels Standardized Test Prep Chapter 34

36. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 3. What does a tapeworm use its scolex for? A. to reproduce B. to attach itself to its host C. to eliminate excess water D. to force food into its mouth Standardized Test Prep Chapter 34

37. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 3. What does a tapeworm use its scolex for? A. to reproduce B. to attach itself to its host C. to eliminate excess water D. to force food into its mouth Standardized Test Prep Chapter 34

38. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 4. Which of the following is true of most rotifers? F. They are parasitic. G. They live in the soil. H. They feed with the help of cilia. J. They have a gastrovascular cavity. Standardized Test Prep Chapter 34

39. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 4. Which of the following is true of most rotifers? F. They are parasitic. G. They live in the soil. H. They feed with the help of cilia. J. They have a gastrovascular cavity. Standardized Test Prep Chapter 34

40. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued The figure below shows the internal structure of a planarian of the genus Dugesia. Use the figure to answer the questions that follow. Standardized Test Prep Chapter 34

41. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 5. What type of animal is shown in the figure? A. flatworm B. tapeworm C. roundworm D. rotifer Standardized Test Prep Chapter 34

42. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 5. What type of animal is shown in the figure? A. flatworm B. tapeworm C. roundworm D. rotifer Standardized Test Prep Chapter 34

43. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 6. What is the structure labeled X? F. the brain G. the mouth H. an eyespot J. a nerve cord Standardized Test Prep Chapter 34

44. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 6. What is the structure labeled X? F. the brain G. the mouth H. an eyespot J. a nerve cord Standardized Test Prep Chapter 34

45. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 7. What is the structure labeled Y? A. the mouth B. a flame cell C. an eyespot D. the gastrovascular cavity Standardized Test Prep Chapter 34

46. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 7. What is the structure labeled Y? A. the mouth B. a flame cell C. an eyespot D. the gastrovascular cavity Standardized Test Prep Chapter 34

47. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 8. fluke : schistosomiasis :: filarial worm : F. trichinosis G. elephantiasis H. encysted meat J. swimmer’s itch Standardized Test Prep Chapter 34

48. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 8. fluke : schistosomiasis :: filarial worm : F. trichinosis G. elephantiasis H. encysted meat J. swimmer’s itch Standardized Test Prep Chapter 34

49. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued The figure below shows the internal structure of a rotifer. Use the figure to answer the question that follows. Standardized Test Prep Chapter 34

50. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 9. Which structures are involved in excretion? A. K and L B. L and O C. M and N D. M and P Standardized Test Prep Chapter 34

51. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 9. Which structures are involved in excretion? A. K and L B. L and O C. M and N D. M and P Standardized Test Prep Chapter 34

52. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Short Response Planarians and rotifers eliminate water through a network of excretory structures that run the length of the body. Explain why the excretory structures in planarians and rotifers are called flame cells. Standardized Test Prep Chapter 34

53. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Short Response, continued Planarians and rotifers eliminate water through a network of excretory structures that run the length of the body. Explain why the excretory structures in planarians and rotifers are called flame cells. Answer: The beating of the cilia in flame cells draws water from surrounding tissue. It is the motion of the cilia that resembles the flickering of a flame. Standardized Test Prep Chapter 34

54. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Prep Chapter 34 Extended Response Base your answers to parts A & B on the information below. Parasitic flatworms have life cycles that include primary and intermediate hosts. Part A Distinguish between primary and intermediate hosts in flatworms. Part B Sequence the life cycle of a beef tapeworm. Identify the primary and intermediate hosts.

55. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Prep Chapter 34 Extended Response, continued Answer: Part A Primary hosts nourish the adult parasite. Intermediate hosts nourish the larval parasite. Part B: Adult tapeworms live in the intestines of the primary host, humans. Mature proglottids are shed in the feces and release eggs. Eggs ingested by cows, the intermediate host, develop into larvae, burrow into muscle tissue, and develop into adults when a human eats infected, undercooked beef.