Zoology Reading Assignment
Chapter 9
Section 1 (p. 127-135)
1. What is Physalia physalis?
2. How long can the tentacles of Physalia physalis be?
3. Compare and contrast the colonial hypothesis and the syncytial hypothesis of
multicellular origins.
4. What does monophyetic mean?
5. What group of ancestral protists is thought to be the origin of animals?
6. What does the name Porifera mean?
7. What are the characteristics of the phylum Porifera?
8. Describe and give examples of organisms in the following classes:
a. Calcarea
b. Hexactinellida
c. Demospongiae
9. What are the functions of the following specialized cells?
a. Pinacocytes
b. Mesenchyme cells
c. Choanocytes
10. What are the three body forms in sponges?
11. What do sponges eat?
12. Are sponges monoecious or dioecious?
13. Why do sponges not self-fertilize?
14. What is a larva?
15. What is a gemmule?
16. What type of symmetry do members of the phylum Cnidaria have?
17. Why is radial symmetry advantageous for sedentary animals?
18. What are the characteristics of cnidarians?
19. What type of organization do cnidarians possess?
20. What is the mesoglea?
21. What is a cnidocyte?
22. What are nematocysts?
23. Distinguish between a polyp and a medusa.
24. What is the function of the gastrovascular cavity?
25. What do cnidarians eat?
26. Describe the hydrostatic skeleton.
Section 2 (page 136-145)
1. Describe how polyps and medusae move.
2. What determines the extent to which a nerve impulse spreads in a cnidarian?
3. How do cnidarians exchange gases and wastes?
4. Are cnidarians monoecious or dioecious?
5. What is a planula?
6. How do medusae form?
7. What three features distinguish hydrozoans from other cnidarians?
8. What is Obelia?
9. Which hydrozoan predominates in the medusa stage?
10. What is the common freshwater hydrozoan?
11. Which class of cnidarians are the “true jellyfish”?
12. What is Mastigias quinquecirrha?
13. Where is Aurelia found?
14. What are rhopalia?
15. Which class of cnidarians is colonial and lack medusae including the anemones
and corals?
16. How do anthozoan polyps differ from hydrozoan polyps?
17. Describe sea anemones.
18. How do anemones move?
19. What do anemones eat?
20. What is protandry?
21. What type of coral forms coral reefs?
22. What are zooxanthellae and how do they aid in coral reef formation?
23. What are some examples of the octacorallian corals?
24. What are the characteristics of the phylum Ctenophora?
25. What are comb rows?
26. Distinguish between members of the classes Tentaculata and Nuda.