Birds

1. Reptile like, but birds have an outer layering of feathers, 2 legs covered in scales that are used for walking or perching, and front limbs modified into wings. Birds

2. Environment • Numerous and diverseenvironments • Interact with natural environments and human populations • Many migrate long distances • Food Source • Maintain heat by eating food • Have beaks or bills that are adapted to what they eat • Lack back teeth therefore cannot break down food by chewing • Have a gizzard that helps with the breakdown of food

3. Maintaining Homeostasis - Internal (Circulation, Respiration, Excretion) • Have air sacs that take in oxygen • 4 chamber heart and two separate circulatory loops • Wastes are removed from blood by kidneys and made into uric acid. Most is reabsorbed leaving uric acid crystals in white pasty form that comes out as bird droppings Maintaining Homeostasis - External (Response) • Large brain for their body • Well-developed eyes and sizable optic lobes in the brain • See color well in many cases better than humans • Hear very well, not a good sense of taste or smell

4. Movement • Most birds fly but some cannot • Ones that cannot get around by walking, running or swimming • Skeletal and muscular systems of flying birds exhibit adaptations that enable flight Reproduction • Separate male and female • Eggs are amniotic- similar to eggs in reptiles but have hard outer shells • Incubate eggs until they hatch • When ready to hatch the chick uses its small beak to crack the egg • Evolutionary Milestone • Endotherm (warm-blooded – internally control body temperature) • Covered with feathers, wings • Lay eggs

5. Picture and Vocabulary • Picture on page 809 Figure 31-14 • Vocabulary: Feather (806), Endotherm (808)