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Birds

Birds. Chapter 42. Origin and Evolution of Birds. Section 42.1. Important characteristics. Feathers – only birds have them! Wings – modified forelimbs Lightweight, rigid skeleton – hollow bones Endothermic metabolism – 104-106 o F Unique respiratory system – most efficient

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Birds

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  1. Birds Chapter 42

  2. Origin and Evolution of Birds Section 42.1

  3. Important characteristics • Feathers – only birds have them! • Wings – modified forelimbs • Lightweight, rigid skeleton – hollow bones • Endothermic metabolism – 104-106o F • Unique respiratory system – most efficient • Beak – no teeth • Oviparity – eggs incubated by parents

  4. Evolution • Similarities to dinosaurs: • Flexible, S-shaped neck • Unique ankle joint • Hollow bones • Birds evolved from small, fast-running carnivorous dinosaurs • Oldest bird fossil - Archaeopteryx

  5. Archaeopteryx • Jurassic period – 150 million years ago • Similar to modern birds because: • Hollow bones • Furcula: fused collarbone (aka wishbone) • Feathers • Similar to dinosaurs because: • Teeth • Claws on forelimb • Long, boney tail

  6. Origin of flight Video • Two major hypotheses: • Ancestors were tree dwellers that ran along branches and jumped from tree to tree, gliding wings first evolved then the ability to flap came later. • Ancestors were land dwellers that leapt after their prey, wings served to trap or knock down prey and over time became large enough to fly.

  7. Feathers • Modified scales • Two main functions: • Provide lift for flight • Conserve body heat • Types of feathers: • Down feathers – insulation • Contour feathers – streamline shape, coloration, insulation • Flight feathers – on wings and tail for flight

  8. Parts of a feather

  9. Structure of the feather • Follicles: tiny pits that feather develops from • Rachis (Shaft): emerges from the follicle • Vanes: 2 vanes on opposite side of shaft • Barbs: branches of the vane • Barbules: projections on the barbs with microscopic hooks • Keratin: protein that makes up the feather

  10. Care of feathers • Preening: use beak to rub feathers with oil secreted by the preen gland at the base of the tail. • Molting or shedding of feathers periodically

  11. Characteristics of Birds Section 42.2

  12. Skeleton & Muscles • Thin, hollow bones fused together • Sternum: breastbone is attachment point for flight muscles • Pygostyle: last fused vertebrae that supports the tail feathers • Flight muscles account for 50% of bird’s weight

  13. Metabolism • Endothermic therefore require large quantities of food to generate heat • Aquatic birds have a layer of fat to insulate • Cannot go through long periods of time without food

  14. Digestive & Excretory Systems • Path of food:mouth  esophagus  crop  2-part stomach (proventriculus & gizzard)  small intenstine with bile from liver  large intestine  cloaca  vent • Path of wastes:blood  kidneys  ureters  cloaca (mixes with feces)  vent

  15. Digestive System

  16. Respiratory System • Highly efficient • Path of air:nostrils  trachea  branched bronchi  lungs (25%) or air sacs (75%) • Air sacs: • 9 total • Stores excess air • Allows for oxygenated air in lungs during exhale and inhale

  17. Respiratory System

  18. Circulatory System • Rapid heartbeat • Up to 1000 beats per minute! • 4 chambered heart • Like mammals

  19. Nervous System & Sense Organs • Large brains (relative to body size) • Some birds have color vision and/or binocular vision • Some birds have a developed sense of smell • Sense of hearing also important

  20. Reproduction • Sperm movement: testies  vasa deferentia  cloaca  female’s cloaca • Egg movement:ovary  oviduct  fertilized by sperm  addition of shell  cloaca  vent

  21. Nest Building & Parental Care • Lay eggs in nest • Methods of rearing young: • Precocial: active as soon as hatch • Atricial: helpless when born • One or both parents incubate eggs by sitting on them and covering them with theirbrood patch • Thickened, featherless patch of skin on abdomen

  22. What type is this? Video

  23. Video Migration • Seasonal movement of birds from one habitat to another • Cues to help navigate: • Position of sun and stars • Topographical landmarks • Magnetic field • Air pressure • Ornithologist: biologist that study birds

  24. Classification of Birds Section 42.3

  25. Diversity • Beak and claws infer diet and habitat • Most widespread terrestrial animal on planet • 23 orders of birds

  26. Order Anseriformes • Examples: swans, geese, and ducks • Aquatic • Webbed feet • Flattened bill • Precocial young, care by female

  27. Order Strigiformes • Examples: owls & nocturnal raptors • Sharp, curved beak • Sharp talons • Keen sense of hearing to detect prey

  28. Order Apodiformes • Examples: hummingbirds & swifts • Small, fast-flying • Tiny feet • Long, narrow beak

  29. Order Psittaciformes • Examples: parrots, parakeets, macaws, cockatoos, & cockatiels • Live in the tropics • Strong, hooked beak for opening seeds • Two toes forward, two toes backward for climbing & perching • Highly vocal

  30. Order Picformes • Examples: woodpeckers & toucans • Nest in tree cavities • Diversity of bills based upon diet • Same feet as parrots

  31. Order Passeriformes • Examples: familiar birds (robins, blue jays, cardinals, etc) • perching birds: 3 toes forward, 1 toe backward • songbirds:males produce songs to attract mate and warn away other males • Syrinx produces sound at base of trachea

  32. Order Columbiformes • Examples: pigeons & doves • Plump-breasted, small heads • Short neck, legs, and beak • Crop secretes nutritious milk-like fluid to feed young • Crop milk

  33. Order Ciconiiformes • Examples: herons, storks, raptors, & penguins • World-wide distribution • Habitat determines adaptations • Many are wading birds

  34. Order Galliformes • Examples: turkeys, pheasants, chickens, grouse, & quail • Fowl • Terrestrial birds • Plump-bodies with limited flying ability

  35. Order Struthioniformes • Examples: ostriches & emus • World’s largest birds • Reduction in toe number to allow for fast running

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