Unit J — Simple Invertebrates

1. Which of the following combinations of organisms contains only radially symmetrical animals?
Jellyfishes, sponges, and roundworms.
Roundworms, hydra, and sea anemones.
Sponges, jellyfishes, and Portuguese men-o-war.
Portuguese men-o-war, roundworms, and flukes.

2. Cephalization MOST ACCURATELY refers to the development of
a brain.
a head.
a scolex.
an anterior end.

3. Which pattern of digestive system allows for the greatest organ development?
Sac-like pattern.
Tube-like system.
Gastrovascular cavity.
Intracellular digestion by lysosome activity.

4. Which of the following combinations of organisms contains only sessile animals?
Flukes and tapeworms.
Sponges, hydras, and sea anemones.
Jellyfishes, planaria worms, and tapeworms.
Flukes, tapeworms, and planaria worms.

5. Animals are diploid (2N) and produce gametes that are haploid (N). This statement is
never true.
usually true.
always true.
occasionally true.

6. Sessile aquatic animals are more likely to be
radially symmetrical, have separate sexes and reproduce by mating.
radially symmetrical and hermaphroditic and reproduce by broadcasting.
bilaterally symmetrical, have separate sexes and reproduce by mating.
bilaterally symmetrical and hermaphroditic and reproduce by broadcasting.

7. Which of the following correctly describes the water flow through a sponge?
In and out through the osculum.
In and out through the porocytes.
In through porocytes and out the osculum.
In through the osculum and out through the porocytes.

8. Which of the following is the most complete list of functions that occur by diffusion in a jellyfish?
Excretion and circulation.
Respiration and excretion.
Respiration and circulation.
Respiration, excretion, circulation.

9. Which of the following is true about stinging cells and collar cells?
They are homologous structures associated with the digestive system.
Stinging cells are specializations of the ectoderm; collar cells are specializations of endoderm.
Collar cells are specializations of the ectoderm; stinging cells are specializations of endoderm.
Collar cells are members of colonies of cells; stinging cells are specializations of the ectoderm.

10. What are the functions of a gastrovascular cavity?
Digestion and excretion only.
Excretion and circulation only.
Digestion and circulation only.
Digestion, excretion and, circulation.

11. Which of the following animals has a nerve net?
Sponge.
Jellyfish.
Planaria.
Tapeworm.

12. Which of the following animals is a member of class Scyphozoa?
Hydra.
Jellyfish.
Planaria.
Sea anemone.

13. Which of the following correctly describes the tissue layers in the animals indicated?
Jellyfish — 2 layers; tapeworm —3 layers; roundworm — 3 layers.
Jellyfish — 2 layers; tapeworm — 3 layers; roundworm — 4 layers.
Jellyfish — 2 layers; tapeworm — 2 layers; roundworm — 3 layers.
Jellyfish — 3 layers; tapeworm — 3 layers; roundworm — 4 layers.

14. What system do flame cells and nephridiopores belong to?
Excretory system of planaria.
Circulatory system of planaria.
Excretory system of roundworms.
Circulatory system of roundworms.

15. What is the advantage to a parasitic worm of having multiple hosts during its life cycle?
Finding a mate.
Distributing their young.
Infecting a wider range of animals.
Sampling a wider range of nutrient sources.

16. A parasitic worm that has a dormant stage in a mammal can usually be found in a
cyst.
snail.
scolex.
proglottid.

17. A human with a tapeworm most likely got it by consuming
raw snails.
unsanitary water.
poorly cooked meat.
unwashed leafy vegetables.

18. If a pin were poked into a nematode from the outside into the intestine, what would it pass through?
Ectoderm, mesoderm, pseudocoelom, endoderm.
Ectoderm, pseudocoelom, mesoderm, endoderm.
Ectoderm, mesoderm, pseudocoelom, mesoderm, endoderm.
Ectoderm, mesoderm, endoderm, pseudocoelom, mesoderm, endoderm.

19. Which of the following best describes the movement of a nematode?
Crawling.
Swimming.
Ciliated gliding.
Whipping back and forth.

20. The development of a coelom is coupled with the earliest specialization of a/an
nervous system.
excretory system.
circulatory system.
respiratory system.