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2. Resources Chapter Presentation Visual Concepts Transparencies Standardized Test Prep

3. Chapter 42 Birds Table of Contents Section 1 Origin and Evolution of Birds Section 2 Characteristics of Birds Section 3 Classification

4. Section 1 Origin and Evolution of Birds Chapter 42 Objectives • Identifyand describe seven major characteristics of birds. • Listthree similarities between birds and dinosaurs. • Describethe characteristics of Archaeopteryx. • Summarizethe two main hypotheses for the evolution of flight.

5. Section 1 Origin and Evolution of Birds Chapter 42 Characteristics There are seven characteristics all birds share • Feathers • Wings • Lightweight, rigid skeleton • Endothermic metabolism • Unique respiratory system • Beak • Oviparity

6. Section 1 Origin and Evolution of Birds Chapter 42 Characteristics of Birds

7. Section 1 Origin and Evolution of Birds Chapter 42 Evolution There are several similarities between birds and some dinosaurs: • Flexible S-shaped neck • Unique ankle joint • Hollow bones

8. Section 1 Origin and Evolution of Birds Chapter 42 Evolution, continued The oldest known bird fossils are in the genus Archaeopteryx, which date from the late Jurassic Characteristics of Archaeopteryx • Feathers on forelimbs, body and tail • Hollow bones and a furcula (fused collarbones also called a wishbone) • Teeth • Claws on forelimbs • Long, bony tail

9. Section 1 Origin and Evolution of Birds Chapter 42 Evolution, continued Archaeopteryx had characteristics of birds and dinosaurs.

10. Section 1 Origin and Evolution of Birds Chapter 42 Evolution, continued Origin of Flight • One hypothesis proposes that the ancestors of birds were tree dwellers that developed the ability to glide between trees. • Another hypothesis suggests that the ancestors of birds were ground-dwelling and first used feathers to stabilize them when they leapt after prey.

11. Section 1 Origin and Evolution of Birds Chapter 42 Phylogenetic Diagram of Birds, Reptiles, and Mammals

12. Section 1 Origin and Evolution of Birds Chapter 42 Adaptations for Flight

13. Section 2 Characteristics of Birds Chapter 42 Objectives • Describethe structure of a contour feather. • Identifytwo modifications for flight seen in a bird’s skeletal system. • Contrastthe function of the gizzard with that of the crop. • Tracethe movement of air through the respiratory system of a bird. • Explainthe differences between altricial and precocial young.

14. Section 2 Characteristics of Birds Chapter 42 Characteristics of Birds

15. Section 2 Characteristics of Birds Chapter 42 Feathers Feathers are modified scales that serve two primary functions: providing lift for flight and conserving body heat. • Feathers develop from tiny pits in the skin called follicles. • Feathers have a shaft, two vanes, barbs and barbules.

16. Section 2 Characteristics of Birds Chapter 42 Feathers, continued There are three basic types of feathers: • Down feathers - soft, fluffy feathers that cover young birds and provide an insulating undercoat in adults • Contour feathers - smooth feathers that give adult birds’ bodies a streamlined shape and provide insulation • Flight feathers - specialized contour feathers located on the wings and tail that are long and rigid

17. Section 2 Characteristics of Birds Chapter 42 Feathers, continued Feathers are cared for by a process called preening. • Preening occurs when birds use their beaks to rub their feathers with oil. • The preen gland is located at the base of the tail and secretes oils that keep feathers healthy and waterproof. • Birds periodically shed and regrow their feathers in a process called molting.

18. Section 2 Characteristics of Birds Chapter 42 Contour Feather Structure

19. Section 2 Characteristics of Birds Chapter 42 Parts of a Feather

20. Section 2 Characteristics of Birds Chapter 42 Preening

21. Section 2 Characteristics of Birds Chapter 42 External Structure of Birds—Bald Eagle

22. Section 2 Characteristics of Birds Chapter 42 Skeleton and Muscles • The avian skeleton is light and strong. • Bones are thin and hollow. • Many bones are fused, which makes the skeleton more rigid than that of a reptile or mammal. • A large keel-shaped sternum allows attachment of large flight muscles. • The pygostyle, fused terminal vertebrae, supports the tail feathers.

23. Section 2 Characteristics of Birds Chapter 42 Avian Skeleton

24. Section 2 Characteristics of Birds Chapter 42 Skeleton and Muscles, continued • Flight involves complex wing movements. Each movement uses a different set of muscles. • Birds have large, powerful flight muscles in the breast and wings. • In some birds, flight muscles account for up to 50% of the body weight.

25. Section 2 Characteristics of Birds Chapter 42 Metabolism • Birds are endothermic. • Birds have a very high metabolic rate. • Rapid breathing and digestion of large quantities of food support this high metabolic rate. • Birds’ digestive and respiratory systems have evolved to support a high metabolism.

26. Section 2 Characteristics of Birds Chapter 42 Digestive and Excretory Systems The avian digestive system consists of: • Beak - breaks open or tears apart food • Esophagus - passage from the mouth to the crop • Crop - stores and moistens food • Stomach - consists of two parts • proventriculus - acids and digestive enzymes begin breaking down food • gizzard - kneads and crushes food aided by stones which the bird swallows • Small intestine - absorbs nutrients • Large intestine - absorbs water • Cloaca - eliminates wastes from the body

27. Section 2 Characteristics of Birds Chapter 42 Bird Digestive System

28. Section 2 Characteristics of Birds Chapter 42 Digestive and Excretory Systems, continued The avian excretory system is efficient and lightweight. • Birds have two kidneys that filter nitrogenous wastes. • Birds do not have a urinary bladder. • Birds excrete concentrated uric acid, which conserves water. • Uric acid mixes with feces and is excreted through the cloaca.

29. Section 2 Characteristics of Birds Chapter 42 Respiratory System • The avian respiratory system is highly efficient and allows birds to maintain a high metabolic rate. • Air sacs connected to the lungs provide a constant flow of oxygenated air to the lungs. • This also allows birds to function at high altitudes.

30. Section 2 Characteristics of Birds Chapter 42 Avian Lung Structure

31. Section 2 Characteristics of Birds Chapter 42 Bird Lungs

32. Section 2 Characteristics of Birds Chapter 42 Circulatory System The avian circulatory system is similar to that of both crocodiles and mammals. • Birds have a four chambered heart. • Deoxygenated blood is completely separated from oxygenated blood in the heart. • Birds have a relatively rapid heartbeat. • Unlike mammals, avian red blood cells have nuclei.

33. Section 2 Characteristics of Birds Chapter 42 Avian Heart Structure

34. Section 2 Characteristics of Birds Chapter 42 Bird Heart

35. Section 2 Characteristics of Birds Chapter 42 Nervous System and Sense Organs • Birds have large brains relative to their body size. • The cerebellum, which controls flight related functions, is large. • The cerebrum, which controls complex behavior, is also well developed. • The optic lobes are also very large.

36. Section 2 Characteristics of Birds Chapter 42 Parts of a Bird Brain

37. Section 2 Characteristics of Birds Chapter 42 Nervous System and Sense Organs, continued Birds have very good vision. • Vision is important for flight and feeding. • Most birds have strong color vision. • Some birds have eyes located near the sides of the head, which provide a wide field of vision. • Predatory birds have eyes that are more forward-facing, which provides depth perception.

38. Section 2 Characteristics of Birds Chapter 42 Nervous System and Sense Organs, continued Birds have good hearing. • Hearing is important for songbirds and nocturnal birds. • Nocturnal predators rely on hearing to locate prey. • Birds lack external ears. • Owls have feathers around their ear openings that direct sound into the ear.

39. Section 2 Characteristics of Birds Chapter 42 Reproduction Male: • Sperm is produced in two testes, located anterior to the kidneys. • Sperm passes through small tubes called vasa deferentia (singular vas deferens). • Sperm exits through the cloaca.

40. Section 2 Characteristics of Birds Chapter 42 Reproduction, continued Female: • Eggs are produced in a single ovary, located on the left side of the body. • Eggs are released by the ovary and pass into a funnel shaped tube called the oviduct. • Eggs are fertilized in the oviduct. • In the oviduct, eggs are encased in a protective covering and a shell. • Eggs are released through the cloaca.

41. Section 2 Characteristics of Birds Chapter 42 Reproduction, continued Nest building and parental care • Birds usually lay their eggs in a nest. • One or both parents warm (incubate) the eggs and guard the nest. • Birds sit on their eggs and cover them with a thickened featherless patch of skin called the brood patch. • Birds usually provide extensive parental care.

42. Section 2 Characteristics of Birds Chapter 42 Reproduction, continued Birds have two general patterns for rearing young • Precocial: Young incubate for long periods. Young can walk, swim, and feed as soon as they hatch. This pattern is most often seen in ground-nesting birds. • Altricial: Eggs hatch quickly. Young hatch blind, featherless, and helpless and require extensive parental care. This pattern is most often seen in birds that nest above ground.

43. Section 2 Characteristics of Birds Chapter 42 Internal Structure of Birds—Bald Eagle

44. Section 2 Characteristics of Birds Chapter 42 Anatomy of a Bird

45. Section 2 Characteristics of Birds Chapter 42 Migration Migration is the seasonal movement of animals from one habitat to another habitat. • Many birds nest in temperate regions, and spend winters in tropical regions. • Bird migration patterns are studied by ornithologists - biologists who study birds. • Birds may use landmarks, star position, sun position, Earth’s magnetic field, changes in air pressure, or low-frequency sounds to navigate during migration. • Many species rely on fat reserves for energy during migration. Some species gather and feed along the migration route at places called staging sites.

46. Section 3 Classification Chapter 42 Objectives • Describethe relationship between beak shape and diet in birds. • List10 major orders of living birds, and name an example of each order. • Describethe function of the syrinx.

47. Section 3 Classification Chapter 42 Diversity Beak and foot adaptation reveal information about a bird’s habitat and diet, for example: • Predators: powerful, hooked beaks and sharp talons (claws) • Seed eaters: strong wide beaks, small feet for perching • Nectar feeders: long thin beaks • Flightless birds: strong legs for walking and running

48. Section 3 Classification Chapter 42 Avian Adaptations Type of Bird Beak Adaptations Foot Adaptations Type of Bird Beak Adaptations Foot Adaptations Songbirds (e.g., cardinal, robin) Seed-cracking: Short, thick, strong beak Perching: Toes can cling to branches; one toe points backwards Long-legged waders Fishing: Long, slender, spear-shaped beak for fishing Wading: Long legs; toes spread out over a large area to support bird on soft surfaces Insect-catching: Long, slender beak for probing Hummingbirds Probing: Thin, slightly curved beak for inserting into flowers to sip nectar Hovering: Legs so small the bird cannot walk on the ground; tiny feet Wood peckers Drilling: Strong, chisel-like beak Grasping: Feet with two toes pointing forward and two pointing backward Birds of prey Tearing: Curved, pointed beak for tearing apart prey Grasping: Powerful, curved talons for seizing and gripping prey Parrots Cracking, tearing: Short, stout, hooked beak used to crack seeds and nuts and to tear vegetation Climbing/grasping: Strong toes, two pointing forward, two pointing backward; adapted for perching, climbing, and holding food. Ducks Sieving: Long, flattened, rounded bill Swimming: Three toes linked by webs for improved swimming

49. Section 3 Classification Chapter 42 Beak Adaptations and Bird Diversity

50. Section 3 Classification Chapter 42 Foot Adaptations and Bird Diversity