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Chapter 42 Birds.

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Presentation on theme: "Chapter 42 Birds."— Presentation transcript:

1 Chapter 42 Birds

2 Feathers-evolved from scales
Bird Characteristics Feathers-evolved from scales

3 Wings-a bird’s forelimbs are modified into a pair of wings

4 Lightweight, Rigid Skeleton-Bones are thin-walled and hollow

5 Endothermic metabolism-a bird’s rapid metabolism supplies the energy needed for flight
Hummingbirds Eagle

6 Bird Characteristics Unique respiratory system-The lungs are connected to several sets of air sacs Bird breathing Breathing

7 Beak-no modern bird has teeth

8 Oviparity-lay amniotic eggs encased in a hard, calcium-containing shell

9 Evolution Scientific evidence suggests that birds arose from dinosaurs
Dinosaur Chickens

10 Similarities between birds and dinosaurs:
Flexible, S-shaped neck Unique ankle joint Hollow bones

11 Evolution The earliest flying vertebrates were dinosaurs.
The oldest known bird fossils are Archaeopteryx.

12 Had hollow bones and a furcula-fused pair of collarbones; “wishbone”

13 Feathers Feathers-modified scales Serve two primary functions:
Provide lift for flight Conserve body heat Took the place of scales as the body covering of birds.

14 Preening-birds use their beaks to rub their feathers with oil secreted by a preen gland.
Bird Preening

15 Bones Skeleton is: Composed of thin, hollow bones.
Composed of many fused bones. More rigid than a reptile’s.

16 Sternum-breastbone-attachment point for flight muscles

17 Pygostyle-fused terminal vertebrae of the spine, supports the tail feathers, adds lift, and aids in steering and braking

18 Metabolism Birds are endothermic.
Cannot go for long periods without eating Bird eating

19 Digestion Birds do not have teeth, and are not able to chew food.
Crop-temporarily stores food. Gizzard-grinds food.

20 Have a four-chambered heart
Circulatory System Have a four-chambered heart

21 Respiratory System Bird respiration is very efficient because a system of air sacs permits birds to have oxygenated air in their lungs during both inhalation and exhalation. Syrinx-produces songs Lyre bird

22 Nervous System and Sense Organs
Relative to their size, birds have large brains Have keen, strong, color vision that aids them in finding food

23 Eggs are encased in a hard shell.
Reproduction Eggs are encased in a hard shell.

24 Migration Migration-the seasonal movement of animals from one habitat to another Bird migration


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