KEY CONCEPT Birds have many adaptations for flight.

1. KEY CONCEPT Birds have many adaptations for flight.

2. Birds evolved from theropod dinosaurs. • Birds and many theropods share anatomical features. • hollow bones • fused collarbones that form V-shaped wishbone • rearranged muscles in the hips and legs • “hands” that have lost their fourth and fifth fingers • feathers

3. The oldest undisputed fossilized bird is Archaeopteryx.

4. lung gizzard kidney crop small intestine pectoral muscle large intestine cloaca sternum(keel) liver heart A bird’s body is specialized for flight. • Birds have several unique features that allow them to fly. • wings to produce flight • strong flight muscles to move the wings • active metabolism that provides energy to the muscles • hollow bone structure to minimize weight • gonads active during only part of year

5. Wings are structures that enable birds to fly. • airfoil shape • covered with feathers

6. Air sacs help a bird meet its oxygen demand during flight.

7. Birds have spread to many ecological niches. • The shape of a bird’s wing reflects the way it flies. • short and broad • long and narrow

8. lung gizzard kidney crop small intestine pectoral muscle large intestine cloaca sternum(keel) liver heart • The shape of a bird’s wing reflects the way it flies. • wide and broad • stout and tapered

9. Bald eagle green woodpecker blue-footed booby • Differences in the shape of a bird’s beak reflects how it eats. • spearlike • hooked • chisel-shaped

10. blue-footed booby bald eagle green woodpecker • Birds show great diversity in their foot shape. • webbed • heavy claws • different toe location

11. Feathers: Anatomy

12. Feather Types

13. Flight Feathers

14. Flight feathers and the Wing • Primaries • Attached to hand • Asymmetrical vanes • Owls have silent flight because of barbs on front of vane • Generate thrust (forward motion) • Secondaries • Attached to ulna • Generate lift • Tail feathers • Function in steering and braking

15. Wing shapes Great once in the air, but first need to get launched! - Mastery of Flight beginning of video

16. Feather care • Birds preen up to once an hour! • Some preening glands have lipids which resist keratin eating fungi and bacteria

17. Adaptations for flight: Anatomical • Feathers • Wing • Reproduction (internal, eggs) • Bones

18. Anatomical adaptations: Bones (already mentioned) • Lightweight, strutted or hollow • No teeth • Modified forelimb

19. Anatomical adaptations: Bones • Fused bones of pelvis, feet, hands, head • Uncinate processes on ribs • Furcula (wishbone)

20. Flight Adaptations: Physiological adaptations • Endothermic • Separate red and white muscle fibers

21. Flight Adaptations: Red versus White fibers • Red fibers = sustained work, ability to produce heat by shivering • White fibers – powerful stroke but cannot be sustained Pigeon wing and breast? Grouse or turkey wing and breast? Bird leg? Humming bird wing and breast?

22. Flight Adaptations: Circulatory System • High metabolic demands require rapid circulation of high volumes of blood. • Four chambered heart • Double circulatory system (pulmonary and systemic) • Large heart -50-100% larger and more powerful than mammals of the same size.

23. Flight Adaptations: Respiratory System • Mammals: simple but inefficient. 20% of air never contacts a respiratory surface for exchange • Birds require 2 full breaths to move air completely through system. More efficient w/ help of air sacs • In addition to lungs, th ey have ~9 air sacks extending into abdomen, land toward wings

24. Flight Adaptations: Urinary system • How often do you see a bird drink? • Sources: • High metabolism = high metabolic water production(up to 80% of requirements) • Food: particularly birds of prey and insectivores. • Seed eaters need the most water • Free water – streams, watering hole, raindrops, snow

25. Flight Adaptations: Urinary system • Water conservation • Excrete uric acid – a semi-solid with 2x the nitrogen per molecule. Concentrated in cloaca up to 3000x the acid level as in blood

26. Flight Adaptations: No teeth…Digestive system impact? • Crop • Proventriculus (stomach) • Ventriculus (Gizzard) • Intestines • Caecae If a nectar eater, is a gizzard important? What size caecae would a goose have? What other feeding adaptations do birds have?

27. Bird Adaptations: Bill Shape • So important that this is one way birds are classified. Twenty different orders of birds are recognized • Why are there so many different types of birds?

28. Evolutionary Arms Race • Over evolutionary time, we expect natural selection increases the efficiency with which predators detect/capture prey AND also we expect selection to increase prey ability to avoid detection and to escape! • Who wins?

29. Evolutionary Arms Race Predator adaptation Prey Counter-Adaptation Crypsis Polymorphism Space out mimicry • Improved visual acuity • Search image • Limit search to abundant areas • learning Winners? No. Life versus dinner principle. Stronger selection on prey. Predators adapting to a variety of prey species and cannot specialize.

30. Bird Adaptations: Reproductive System • Bird Egg • One functional ovary (less weight) • Nest structure and bird behavior create microclimate for embryo • Laying/incubating eggs is dangerous. Need to avoid predators! • Site choice • Nest structure • Adult behavior