1. Reptiles, Birds, and Mammals are Amniotes Have a membranous sac called the amnion that surrounds & protects the embryo

2. Three characteristics of amniotes decrease their dependency on water 1. Amniotic egg – waterproof egg with a covering – inside the egg is a fluid-filled cavity in which the embryo develops

3. 2. Internal fertilization – male deposits sperm within the reproductive system 3. Water-tight skin – made out of a protein called keratin ; prevents dehydration & acts as a barrier May be hair, nails, scales, or feathers

4. Endotherm Ectotherm -”regulator” -”conformer” -temperature stays constant -temperature changes with -birds, mammals external environment -reptiles, amphibians, fish

5. Reptiles (Class Reptilia)‏ Turtles, lizards, snakes, crocodiles, alligators Water-tight skin is made out of scales – hard, overlapping layers of protein Scales cannot expand, so to grow bigger a reptile must molt Most lay eggs, but some give birth to live young

7. Birds (Class Aves) are endothermic amniotes with specialized adaptations for flight Evolved from small dinosaurs

8. Because birds are endotherms, they lay eggs that must be kept warm by brooding Song Sparrow brood patch

9. Special adaptations for flight: 1. Wing shape – produces lift for flight

10. 2. Feathers – modified scales – function in flight, waterproofing, and endothermy

11. 3. Air sacs – function with lungs in respiration – needed to meet intense oxygen demands for flight – reduces body density (makes it lighter for flight)‏

12. 4. Honeycombed bones makes lighter Bird bone (much lighter)‏ Human bone

13. 5. No teeth to reduce weight of head -instead they have a gizzard , a muscular organ that grinds food

14. Structure fits Function – Beak Shape

15. Arguably the Most Exquisitely Evolved Mating Behaviors Belong to Class Aves