1. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu

2. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Unlike reptiles, birds lack and have a tail that is greatly reduced in Like reptiles, birds have amniotic eggs. They also have feet and legs that are covered with Birds have modified into wings. Characteristics and Diversity of Birds

3. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Characteristics and Diversity of Birds

4. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Key Characteristics of Birds, continued Feathers Feathers are modified reptilian scales. cover the bird’s body and give adult birds their shape. When a bird preens, it spreads oil from its gland over its feathers, cleaning and waterproofing them. cover the body of young birds and are found beneath the contour feathers of adults. Characteristics and Diversity of Birds

5. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Characteristics and Diversity of Birds

6. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Key Characteristics of Birds, continued Strong, The bones of birds are thin and hollow. Some of the bones are fused, providing have a large breastbone with a prominent for muscle attachment. used in flight are attached to the breastbone and fused Characteristics and Diversity of Birds

7. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Characteristics and Diversity of Birds

8. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Key Characteristics of Birds, continued Birds are, which means they generate enough heat through metabolism to maintain a high body Birds have a high rate of, which meets the increased energy requirements of Characteristics and Diversity of Birds

9. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Key Characteristics of Birds, continued Completely Divided As in the crocodilian heart, the of the bird heart is completely divided by a The of the bird heart separates oxygen-rich and oxygen-poor blood, meaning that oxygen is delivered to the body cells more Characteristics and Diversity of Birds

10. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Characteristics and Diversity of Birds

11. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Key Characteristics of Birds, continued Highly Efficient Birds have a high demand for oxygen because they use large amounts of energy Air moves through a bird’s lungs in one direction. Air connected to a bird’s lungs act as holding tanks to enable the one-way flow of air. Characteristics and Diversity of Birds

12. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu (Do Not Draw) Characteristics and Diversity of Birds

13. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu External Structure of Birds – Characteristics and Diversity of Birds

14. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu – Bald Eagle Characteristics and Diversity of Birds

15. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Different of birds are adapted for different ways of life. A bird’s, legs, and feet reveal a great deal about its habits and diet. Some species of birds are highly specialized, while others are very flexible in their Characteristics and Diversity of Birds

16. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Adaptations of Birds, continued Other Adaptations There are many o of birds, each of which is adapted to its particular living conditions. Section 3 Characteristics and Diversity of Birds

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21. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Characteristics and Diversity of Birds