Principles of Animal Biology - Study Sheets
Phylum PlatyhelminthesReturn to the Study Guides Index

The following questions will help you to review the material from the lecture, lab as well as the text.

  1. Briefly characterize the phylum Platyhelminthes.
  2. Flatworms are acoelomates. Explain!
  3. One of the characteristics of the taxon is the flat dorsally-ventrally flattened shape of the organisms. What kind of physiological advantages are associated with such a shape?
  4. Bilateral symmetry favored the evolution of two major aspects of animals. What are these characteristics? Why did bilateral symmetry favor their evolution?
  5. How many species are represented by the taxon? How many of those are free-living? Parasitic?
  6. Briefly describe the taxonomy of the taxon (classes). Which of these classes are parasitic?
  7. Briefly describe the class Turbellaria.
  8. The planarians are often used to describe the structural and functional anatomy of the group. Describe the basic anatomy of a planarian (use Dugesia as example)..
  9. What is the basic structure and function of the tegument? Does the tegument differ between free-living and parasitic species?
  10. How do planarians move?
  11. Are muscles present? If so, how are they arranged in a planarian? Are they only used for movement?
  12. Describe the feeding behavior of a typical planarian. How does a planarian feed, digest and absorb their food?
  13. Polyclad flatworms are often brightly colored due to a variety of pigments. Why?
  14. Many nudibranchs resemble polyclad flatworms (or is it the other way around?). Explain the reason for the similarities.
  15. Flatworms have an enormous innate ability to regenerate. Briefly describe this aspect of the phylum with the help of the regeneration experiments described in lecture.
  16. What are flame cells? Importance?
  17. Briefly outline the nervous system of a planarian. How does this system differ from the members of phylum Cnidaria?
  18. What kind of sensory input do free-living flatworms typically respond to?
  19. What are the eye spots on a planarian. What kind of visual information do they respond to?
  20. How do planarians reproduce?
  21. How do flatworms solve the problems of gas exchange? Excretion of waste?
  22. Briefly describe the class Monogenea.
  23. Briefly describe the class Trematoda.
  24. What are flukes? What is their biological importance?
  25. How do flukes gain access to nutrients?
  26. Describe the species Schistosoma mansoni as a representative of the class Trematoda.
  27. Briefly describe the pathology and importance of the disease schistosomiasis. Where does the disease occur?
  28. Describe the life cycle of Schistosoma mansoni. [Make sure to know and understand this life cycle]
  29. What are miracidia? What are cercariae?
  30. Why is the intermediate host so important to consider as one tries to reduce the incidence of the disease?
  31. Under what kind of conditions are humans most likely to be exposed to the disease?
  32. Briefly describe the class Cestoidea/Cestoda.
  33. What is a scolex? What is a proglottid? [function and structure]
  34. How do these worms reproduce?
  35. Outline the main physiological characteristics of the phylum Platyhelminthes.

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Updated: October  2015