Principles of Animal Biology - Study Sheets
Phylum MolluscaReturn 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. How does the phylum Mollusca correspond in size (number of species) with the other animal phyla we are studying this semester? How many species are found within the phylum?
  2. What kind of animals are found within the phylum Mollusca? Examples of animals?
  3. In what kind of environments do these animals live?
  4. What are some "new" major evolutionary features present in this phylum?
  5. What are the four major body features that these animals have in common? Use the concept of the "ancestral mollusk"  [HAM] to outline the body plan (bauplan) that these animals have. Draw a diagram of the "ancestral" mollusc and label all the major parts of its body.
  6. What is the foot? The visceral mass? The mantle? The head?
  7. What is a radula? What is it used for? Does the structure of the radula vary within the phylum? Why or why not?
  8. Many molluscs have a shell. What is the shell made of? How is the shell produced? Why do not all molluscs have a shell (or do they)?
  9. What is the function of the shell?
  10. Explain the evolutionary pressure/s that led to the evolution of the shell. The ancestors of the molluscs where soft bodied animals without a shell. What events occurred that triggered this major shift?
  11. What are the advantages and disadvantages with having a shell?
  12. When did the phylum Mollusca originate in the fossil record? Is this phylum well represented in the fossil record?
  13. Give a brief overview of the diversity within the phylum Mollusca. What are the names of the four major classes? Which of the four classes is most "ancient"? How do we know?
  14. Explain the concept of adaptive radiation. How is this concept exemplified by the phylum Mollusca? Explain.
  15. Characterize the class Polyplacophora. Where does one find these animals? How are they adapted to that specific environment?
  16. What do chitons feed on? How do they feed?
  17. Make a brief sketch of the body of a chiton.
  18. The class Gastropoda is the largest within the phylum Mollusca. How many species does this class represent? Give a brief overview of the diversity of species within this class.
  19. Explain the phenomenon referred to as torsion. What are the implications of torsion on the anatomy of a Gastropod? What is the evolutionary explanation of torsion?
  20. Is the torsion of a shell and the torsion of the body linked in any way?
  21. What is the importance of Gastropods for humans?
  22. Make a diagram of the anatomy of a typical Gastropod (e.g. a garden snail) and label the major parts of the body.
  23. What is an operculum? A pneumostome?
  24. How do gastropods move?
  25. Gastropods feed on a variety of diets depending on the species. Give a few examples of their diet.
  26. What is a suspension feeder? How do they gather food?
  27. Briefly explain the concept of open circulation. How does it work? What is the difference between open and closed circulation? In which classes within the phylum do you find these systems?
  28. Would you consider that the nervous system in these animals as a complex one? How does it differ between the different classes? How do these animals sense the world?
  29. What is the difference between a dioecious and a monoecious species?
  30. What is a trochophore larvae? A veliger larvae?
  31. Are the nudibranchs typical gastropods? Explain. Many of them are very colorful. Why is that?
  32. Characterize the class Bivalvia. How does this class differ from the class Gastropoda? Draw a figure of the anatomy of a typical bivalve and label major body parts.
  33. How do bivalves feed? Move? Reproduce?
  34. Characterize the class Cephalopoda. Give a few examples of animals found in this taxon.
  35. Compare the class Cephalopoda with the three others you are studying. How do they differ from each other. How are they similar?
  36. What kind of modifications have occurred in the body plan of a Cephalopod (e.g. with the foot as well as the mantle)?
  37. Try to explain why this change occurred from an evolutionary perspective.
  38. Do shells occur within the class Cephalopoda? Explain.
  39. Describe the body structure of the Nautilus. How is this body connected to the origins of this class of animals?
  40. Where do you find the Nautilus? How does this animal capture food? How does it control buoyancy?
  41. How do cephalopods change their colors? Give several reasons for why this feature has become so advanced within the class. What is the ability used for?
  42. Why is the nervous system of Cephalopods so much more advanced compared to the other three classes?
  43. Briefly discuss the the evolution of vision within this class as compared to other animals.
  44. Describe the life cycle of squid.
  45. Make a diagram of the anatomy of a squid and label major structures as well as their function.
  46. Summarize the characteristics of the phylum Mollusca! Make sure to emphasize any new features present within the taxon.


Recommended Reading:  [Note: Angel disables links to Amazon URLs - these are great introductions to aspects of Mollusca]
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Page created by: Peter Svensson
Updated: October 2015