1. Characteristics & Diversity of Birds
Section 34.3

2. Key Characteristics Feathers: Contour feathers – give shape
Flight feathers are contour feathers on wings and tail
Down feathers – on young birds & under contour feathers; provide insulation

3. Contour feather anatomy

4. Down feathers

5. Key Characteristics … Strong, lightweight skeleton
Bones are thin and hollow
Keeled breastbone provides for wing muscle attachment

6. Bird skeleton with keeled breastbone

7. Key Characteristics…
Efficient lungs – contain air sacs which maintain oxygen absorption even when exhaling

8. Bird air sacs

9. High body temperature due to high metabolic rate
Key Characteristics…
Endothermic metabolism
High body temperature due to high metabolic rate

10. Key Characteristics…
Four chambered heart – ventricle is completely divided

11. Bird heart – 4 chambers