27.1 Feeding and Digestion

Understand Key Concepts

1. An animal that relies primarily on intracellular digestion is the

   1. sponge.

   2. clam.

   3. dragonfly.

   4. earthworm.

2. Animals that obtain food by ingesting decaying bits of plant and animal material are called

   1. herbivores.

   2. carnivores.

   3. detritivores.

   4. filter feeders.

3. Algae that live in the bodies of reef-building corals are

   1. parasitic symbionts.

   2. mutualistic symbionts.

   3. occupants that have no effect on the coral animals.

   4. consumed as food by the coral animals.

4. Compare the processes of intracellular and extracellular digestion.

5. Describe the differences between the canine and molar teeth of herbivorous and carnivorous mammals.

6. How do vertebrate filter feeders obtain food?

Think Critically

7. Classify You are observing an animal that has a digestive tract. Does this animal practice intracellular digestion or extracellular digestion? Explain your answer.

8. Pose Questions Hummingbirds eat high-energy foods, such as nectar. Many ducks eat foods that contain less energy, such as plant leaves. What are some research questions you could investigate to discover more about the diet of a bird species and its energy needs?

27.2 Respiration

Understand Key Concepts

9. Most terrestrial insects breathe using a network of structures called

   1. gills.

   2. tracheal tubes.

   3. book gills.

   4. book lungs.

10. In order for the exchange of oxygen and carbon dioxide to take place, an animal's respiratory surfaces must be kept

    1. cold.

    2. dry.

    3. hot.

    4. moist.

11. Most fishes exchange gases by pumping water from their mouths

    1. over their gills.

    2. through the lungs.

    3. over their atria.

    4. through their esophagus.

12. Describe two types of respiratory structures found in terrestrial invertebrates.

13. What respiratory structures do all terrestrial vertebrates possess?

14. With what respiratory structures do aquatic reptiles and aquatic mammals breathe? What inconvenience does this cause when they are underwater?

Think Critically

15. Predict During heavy rains, earthworms often emerge from their burrows. What might happen to an earthworm if it did not return to its burrow when the ground dried out?

16. Infer Land snails have a respiratory structure called a mantle cavity, which is covered with mucus. What might the purpose of the mucus be?

27.3 Circulation

Understand Key Concepts

17. Most arthropods have

    1. no circulatory system.

    2. an open circulatory system.

    3. a closed circulatory system.

    4. skin gills.

18. In a closed circulatory system, blood

    1. comes in direct contact with tissues.

    2. remains within blood vessels.

    3. empties into sinuses.

    4. does not transport oxygen.

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