1. Class Aves Consists of about 10,000 species Characteristics? Feathers
Endothermic
Forelimbs modified into wings
Lay eggs
Four-chambered heart
Scaley feet (What other class has scales?)

2. The exception to the rule:
Can anyone guess the one type of bird that does not lay eggs?
MALES!!!!

3. Why are birds important?
Food web (both as predators and prey)
Guano (droppings) – provides marine ecosystem with organic nitrogen compounds

4. Feathers Down feathers - provide insulation
Contour feathers - cover head and body, provide coloration
Flight feathers - on wings and tail, provide lift
*Species in colder climates tend to have longer feathers and a thicker fat layer than those in warmer climates

5. Preening Birds preen their feathers frequently.
Feathers must be maintained in prime condition to ensure waterproofing and insulation.
Birds preen with their bills. A gland near the base of the tail secretes oil that the bird distributes throughout its feathers.

6. Molting The replacement of all or part of the feathers
Molting occurs in response to a mixture of hormonal changes brought about by seasonal changes.
Can be complete or partial
Pin Feathers

7. Thermoregulation To release heat, birds will:
holds wings away from its body, so both surfaces are exposed to air
Ruffle their feathers to break up the insulating layer of air next to the skin.
Move into shade
Pant
Use eye patches
(not in all species)
Birds that need to stay warm
Often have dark plumage to absorb heat from the sun
On land, king and emperor penguins tip up their feet, and rest their entire weight on their heels and tail, reducing contact with the icy surface

8. Hollow Bones?

9. Location, location, location

10. The lors, or eyepatches, change colors on some during breeding season
Usually once copulation occurs the lors fade back to normal coloration

11. ADVERTISE!

13. Internal Fertiliztion

14. Archeopteryx

15. Evidence of Evolutionary Transitions
What evidence supports that Archaeopteryx is a missing link between Reptilia and Aves?
What evidence supports that there is a link between Reptilia and Mammalia?
Did this article confirm or disprove your original hypothesis?