Mollusca and Annelida Study Guide
Relevant Sections of Text:
 Ch33 692-699
 pg 916-918 & 933-935
Objectives and Study Questions:
1. What are the three main parts of the mollusk body plan and the function of each.
2. Describe the coelum of the typical mollusk
3. What material are mollusk shells based on?
4. Do all mollusks have shells? Explain.
5. What functions does the shell perform?
6. What is a mantle cavity? What structures would it contain?
7. What is a radula? What mollusk groups have a radula and which groups do not have a radula?
8. Describe the digestive system of a typical mollusk
9. What kind of cardiovascular system to most mollusks have? What is the important exception?
10. What is the pigment that carries oxygen in the circulatory system of mollusks?
11. What are the waste removing and osmoregulatory organs of a mollusk?
12. Describe the typically mollusk nervous system.
13. What are two structures that are used for gas exchange in mollusks?
14. Are most mollusks dioecious or monecious?
15. What is a trochophore?
16. What is the common name for members of class polyplacaphora?
17. Describe the shell and body of polyplacaphora?
18. How do polyplacaphores feed and what do they feed on?
19. How do members of polyplacaphores deal/cope with exposure in the intertidal zone?
20. Give some examples of the types of mollusks that belong to class gastropoda.
21. How many shells do gastropods have?
22. Many gastropods undergo torsion, what is torsion?
23. What structure do gastropods use to eat?
24. Are gastropods herbivorous or predatory? Explain.
25. What structures do gastropods use for gas exchange?
26. What are bivalves? Give some examples.
27. Are there terrestrial bivalves?
28. What typical mollusk body parts/structures do bivalves NOT have?
29. What is the function of the adductor muscle in bivalves?
30. How do bivalves feed?
31. What is the function of the foot in bivalves?
32. What are the functions of gills in bivalves?
33. Describe the incurrent and excurrent siphons and how they relate to the mantle cavity in
bivalves as well as feeding in bivalves.
34. Are bivalves mostly sedentary? To what extent do they move around?
35. Give some examples of animals that belong to class Cephalopoda
36. What ecological role to cephalopods play (i.e., are they producers, consumers, parasites,
scavengers, predators, etc.)
37. How has the foot in cephalopods been modified?
38. Describe the feeding structure (mouthparts) of a cephalopod.
39. What is the role of the siphon in cephalopods?
40. In what significant ways are the organ systems of cephalopods different than in most mollusks?
How does this relate to their ecological role?
41. Describe the key physical characteristics and body plan of annelids.
42. What are the three traditional annelid classes discussed in the course?
43. Describe the characteristics of polycheates
44. What are parapodia and chaetae?
45. What are the functions of parapodia in polycheates
46. What are tubeworms? What class do they belong to? How do most obtain their food?
47. What class of annelids do leeches belong to? Are all members of this class blood sucking
parasites?
48. Describe the characteristics of class Hirudinae.
49. What common organism belongs to class oligochaetes?
50. Describe the characteristics of class oligochaetes
51. Using earthworms as a model, describe the digestive, nervous, and circulatory system of
annelids?
52. How do members of class Oligochaetes and Hirudinae perform gas exchange?
53. What structures do annelids use for waste excretion and osmoregulation?
54. What is the general purpose or function of a circulatory system?
55. How are organisms limited in the size (mass) they can attain if they don’t have a circulatory
system?
56. What are the three main components of any type of circulatory system?
57. What are the two types of circulatory system?
58. Describe how an open circulatory system works using the terms: heart, vessels, sinuse(s), pores
(ostia), and hemolymph.
59. Describe how a closed circulatory system works using the terms: heart, vessels, and blood.
60. What is the difference between hemolymph and blood.
61. What are the pros and cons of open and closed circulatory systems
62. Is the need for oxygen (i.e., gas exchange) more closely related to an animal’s mass or an
animal’s surface area?
63. Is the ability to obtain oxygen (i.e., gas exchange) more closely related to the animal’s mass or
its surface area for gas exchange?
64. What limitations does the relationship between an organisms mass and its surface area put on
the organisms size/shape
65. How are respiratory structures designed so that they have the necessary surface area to meet
the gas exchange demand of an organism?
66. Why do gas exchange structures need to be thin?
67. Why would a gas exchange surface need to be well integrated with the circulatory system?
68. Describe the basic structure and function of metanephridia