Assignment

Chapter 15 Homework

1. The hallmarks of birds include _____.

a. hollow bones

b. clawed feet

c. feathers

d. b and c

2. The following are typical modifications of the forelimb of birds: _____.

a. long claws and short ulna

b. keeled sternum and fused carpals

c. short femur and long tarsals

d. fused shoulder joint and clawed hands

3. The only feature of Archaeopteryx not possessed by all theropods was its _____.

a. furculum

b. beak

c. sternum

d. feathers

4. Archaeopteryx was _____.

a. an arboreal glider

b. a fast ground runner

c. aquatic

d. quadrupedal

5. The principal criticism of the cursorial hypothesis of the origin of flight is that _____.

a. the wings of gliders are very different from those of birds

b. feathered dinosaurs are not known

c. catching insects with feathered hands does not seem practical

d. none of the above

6. Archaeopteryx may represent _____.

a. an evolutionary dead end

b. the ancestor of later birds

c. an aberrant theropod

d. all of the above

7. True or False--Birds are the most diverse group of vertebrates except for the bony fishes.

8. True or False-- Birds are descended from tetanuran theropods.

Key Terms: While Reading Chapter 15 define the following terms.

9. Air sac

10. Arboreal hypothesis

11. Aves

12. Bird

13. Cursorial hypothesis

14. Enantiornithine

15. Feather

16. Furcula

17. Pneumatic

18. Pneumatic duct

19. Ratite

20. Solnhofen Limestone

Short Answer:

21. How is a bird’s skeleton designed to make powered flight possible?

22. What evolutionary novelties were shared by theropod dinosaurs and birds?

23. Why do most paleontologists consider Archaeopteryx to be a bird? What similarities does it show to theropod dinosaurs?

24. What other possible ancestors of birds have been identified, and what might they suggest about the similarities of dinosaurs and birds?

25. Compare and contrast the arboreal and cursorial hypotheses of the origin of avian flight.

26. What do Cretaceous birds suggest about the origin and early diversification of the Aves?

27. What impact does their recognition as the ancestors of birds have on our ideas about dinosaurs?