1. Class Aves Phylum Chordata

2. Birds 9700 species distributed over the entire earth ▫Out number any other vertebrate groups except fishes Very diverse ▫Live in forests, prairies, deserts, oceans, caves, mountains “If an animal has feathers, it’s a bird” Oldest fossil of a bird found 147 million years ago ▫May have been mistaken for a theropod dinosaur except that it carried an unmistakable imprint of feathers

3. Birds and Reptiles Similar skull Both have a single middle ear bone Lower jaw composed of 5 or 6 bones Produce Uric acid as waste They lay similar yolked eggs Birds are known as “Glorified Reptiles”

4. Characteristics Elongated S-shaped neck Forelimbs modified as wings Hind limbs adapted for walking Covered in feathers and leg scales Beak – no teeth Well developed Nervous system ▫Large cerebellum Endothermic No bladder ▫Uric acid is produced in a semisolid form ▫Similar to reptiles – water conservation

5. Feathers Lightweight, yet possess remarkable toughness and tensile strength Types of feathers: ▫Contour feathers  Cover and streamline the birds body ▫Down feathers  Hidden beneath the contour feathers ▫Filoplume feathers  Hairlike with no known function ▫Powder-down feather  Found on hawks, parrots, herrons  Tips disintegrate as they grow releasing a powder that helps to waterproof the feathers When a feather is fully grown, the feather will die and molt

6. Skeleton Light and sturdy bones’ ▫Wing bones are light while leg bones are heavier ▫This helps lower the birds center of gravity required for aerodynamic stability Laced with aircavities Diapsid skull ▫Kinetic skull – upper jaw is flexable allowing an increase in gap

7. Feeding Early birds were mostly carnivorous, feeding on small insects Today there is nearly a bird predator to hunt nearly every insect Birds have also been found to eat worms, molluscs, crustaceans, fish, frogs, reptiles, mammals, as well as other birds Nearly 1/5 of birds feed on nectar Some are omnivores- eat anything that is in season.

8. Flight To fly, birds must generate lift forces greater than their own mass to become airborne and they must provide propulsion to move ▫Wings provide both Scientists have two theory's on the evolution of flight ▫Birds began to fly either by climbing to a high place and gliding down ▫Or flap their wings from the ground up 4 different forms of wings ▫See textbook page 601 fig 27.19

9. Migration Not all birds migrate ▫Most North American and European species do Migratory birds have well-established routes Most birds mate in the northern hemisphere during the summer and migrate south during the winters

10. Aves Evolution

11. Living birds are divided into two groups: ▫Superorder Paleognathae – large flightless birds  Ex. Ostrich, Rheas, Emus, Kiwis  5 Orders ▫Superorder Neognathae- flying birds  Ex. Turkeys, Penguins, Flamingos, Storks, Hawks, Pigeons, Parrots, Owls, Hummingbirds, Songbirds  25 Orders