THE BIRDS 425 



These fossils show that the birds and reptiles are rather closely related, 

 for Archaeornis has many reptile-like characteristics, such as teeth and 

 a long bony tail, but since it also had feathers there is no question but 

 that it should be considered a bird. This bird had little, if any, power 

 of flight, for the wings were not well developed and it did not have the 

 enlarged breastbone to accommodate the large breast muscles necessary 

 for effective flying. It also had three claws on the anterior portion of 

 the wings representing the termination of three of the five digits. Thus, 

 the bones of the front leg had not yet become thoroughly adapted to sup- 

 port wings. These and other characteristics give us a good idea as to 

 the line of development through which ancestral birds have passed. 



Classification and Derivation of Scientific Words 



Phylum Chordata (Cont.) 

 Class Aves (L. avis, bird). 



REVIEW QUESTIONS 



1. Discuss the economic importance of birds. 



2. Name the types of feathers found on birds and give the function of each type. 



3. What is meant by the term "warm-blooded" as contrasted with "cold- 

 blooded" ? 



4. What is the significance of the highly developed cerebellum in the birds ? 



5. What special adaptation do birds have that enables them to remain perched on 

 a limb even when asleep ? 



6. Discuss nest building, egg incubation, and protection of the young in the birds. 



7. Discuss bird migration. 



8. Tell how an eagle takes a fish away from an osprey hawk. 



9. How are the eyes of owls adapted for night flying? 



10. How do hummingbirds suck nectar from flowers? 



11. How does the cowbird get foster parents to raise its offspring? 



12. Distinguish between precocious and altricial birds. 



13. When are most young birds in greatest danger from predators? 



14. Why are owls of great value to man? 



15. How are vultures beneficial? 



16. Tell how a bird breathes in flight. 



17. How do quail protect their nest from enemies? 



18. What is the syrinx, where is it found, and how does it function? 



