26.1 Invertebrate Evolution and Diversity

Understand Key Concepts

1. The ancestors of many modern animal phyla first appeared during the

   1. Burgess Period.

   2. Cambrian Period.

   3. Precambrian Era.

   4. Ediacaran Period.

2. Animals in the phylum Porifera include

   1. chordates.

   2. sea stars.

   3. sponges.

   4. sea anemones.

3. Most adult echinoderms show

   1. bilateral symmetry.

   2. top and bottom symmetry.

   3. radial symmetry.

   4. no symmetry.

4. Of the following groups, which has the largest number of species by far?

   1. arthropods

   2. annelids

   3. mollusks

   4. echinoderms

5. What body plan features did Cambrian animals evolve over 10 to 15 million years?

6. What evidence exists to indicate that annelids and mollusks are closely related?

Think Critically

7. Infer Most cnidarians do not swim toward their prey. Instead, they capture prey carried by water currents. How is this behavior related to their body plan?

8. Compare and Contrast How are echinoderms structurally different from arthropods?

26.2 Chordate Evolution and Diversity

Understand Key Concepts

9. The evolution of jaws and paired fins was an important development during the rise of

   1. tunicates.

   2. lancelets.

   3. fishes.

   4. amphibians.

10. Examine the diagrams below. Which of these is a jawed cartilaginous fish?

    

11. Which adaptation is NOT characteristic of reptiles?

    1. scaly skin

    2. shelled egg

    3. gills

    4. lungs

12. Dinosaurs became extinct at the end of the

    1. Cretaceous Period.

    2. Triassic Period.

    3. Carboniferous Period.

    4. Permian Period.

13. The single most important characteristic that separates birds from other living animals is the presence of

    1. hollow bones.

    2. feathers.

    3. two legs.

    4. wings.

14. Which of the following is a placental mammal?

    1. duckbill platypus

    2. whale

    3. kangaroo

    4. koala

15. Which two major groups of fishes evolved from the early jawed fishes and still survive today?

16. What adaptation enables birds to live in environments that are colder than those in which most reptiles live?

17. Describe how the young of monotremes, marsupials, and placental mammals obtain nourishment.

Think Critically

18. Apply Concepts Which anatomical characteristics of nonvertebrate chordates suggest that, in terms of evolutionary relationships, these animals are more closely related to vertebrates than to other groups of animals?