Class notes for 18.1: Birds.

1. 18.1 Birds Page 367

2. Bird Characteristics Vertebrates ENDOTHERMs Organisms with a constant internal body temp. Cells of body stay warm & work normally all the time Only animals w/ feathers Beaks, not teeth Have wings *Not all can fly! Lay eggs w/ shells

3. Origin of Birds Earliest fossil of a bird found in 1861 Like a reptile: scales, jaws with teeth, claws on front limbs Imprint of feathers Evidence birds evolved from reptiles

4. Diversity of BIRDS Over 9,000 species of birds 4 Groups Birds of prey Perching birds Water birds Flightless birds Each bird is adapted to eating a certain kind of food & living in a certain habitat Lifestyle reflected in its: Beak Wings Feet

5. Birds of Prey Eat mammals, fish, other birds Sharp, hooked beaks to tear flesh Claws for grasping Examples: Eagles Hawks Owls Falcons Vultures Osprey

6. Perching Birds Insect eaters Long, pointed beaks work like tweezers Used as drills for boring into wood in search of insects Examples: Woodpeckers Swifts SEED EATERS Thick, strong beak for cracking seeds Examples: cardinal, blue jay, robin

7. Flightless Birds Lost ability to fly Lifestyle makes flight unnecessary Many are fast runners Examples: Ostrich Rhea Penguin

8. Water Birds Have a variety of beaks, wings, and feet Many have webbed feet (swimming) Some have long legs for wading Some have long wings Examples: Flamingos Storks Swans

21. Flight Adaptations Streamlined Lightweight bones Require large amounts of fuel Bird’s body releases energy stored in food quickly & efficiently Cells do this at much quicker rate than other animals This process creates heat (ENDOTHERMS)

22. Flight Adaptations Vision Avoid flying into things See food from far away Large eyes Sharp vision Muscles Flying requires great muscular effort Powerful flight muscles attached to large breastbone

23. Flight Adaptations Bones Hollow, lightweight bones Cross-supports inside bones for support

24. Bird skeleton

25. Flight Adaptations Digestive System Must take in large and steady amount of food High Energy needs CROP stores the food and releases it in steady stream for digestion GIZARD grinds up food for easy digestion

26. Bird digestion system

27. Flight Adaptations Air Supply Special breathing system – provide blood with blood In addition to lungs, birds have air sacks to increase amount of oxygen Heart 4 chambered: keeps low and high oxygen blood separate Provides flight muscles with oxygen

28. Feathers Needed to fly Most feathers: CONTOUR feathers Interlocking barbs DOWN feathers: fluffier, traps layer of air next to body – heat, insulation

29. Physics of flight Flying made easer b/c wings provide LIFT Wing shape is key Upper surface of wing is rounded Air takes longer to go around curved upper part than bottom flat surface

30. Physics of flight Air takes longer to go around curved upper part than bottom flat surface Air above wing must move faster to cover distance in same amount of time The different air speed above & below creates difference in air pressure Pressure under wing HIGHER Thus, more force pushing UP (under wing) than DOWN (on top of wing) Results in lift

31. migration Why? Cold & shortage of food MIGRATE: move to different place during part of every year Many travel same routes every year

32. reproduction Similar to reptiles Eggs fertilized in female body Eggs must stay warm – have to INCUBATE Many species - male & female take turns one finds food, one incubates Attachment b/n male & female called Pair-Bonds

33. Bird eggs Hard shell Keeps embryo from being crushed during incubation Bird egg contains: ALBUMEN & YOLK – provides food for embryo