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19.5: Birds

Difficulty Level: At Grade Created by: CK-12

Lesson 19.5: True or False

Name___________________ Class______________ Date________

Write true if the statement is true or false if the statement is false.

_____ 1. Birds are endothermic tetrapod vertebrates.

_____ 2. Birds lay amniotic eggs with hard, calcium carbonate shells.

_____ 3. Birds are the youngest but most numerous class of vertebrates on Earth.

_____ 4. All modern birds have wings, feathers, and beaks.

_____ 5. Wings are modified front legs.

_____ 6. Down feathers are short and fluffy; they help a bird fly downward.

_____ 7. Birds have an organ called a crop, which contains stones that grind food.

_____ 8. Most birds abandon their young at birth.

_____ 9. Flightless birds are good at running or swimming.

_____ 10. Courtship in birds can involve singing or dancing.

_____ 11. Bird beaks have adapted for the food they eat.

_____ 12. Some birds stay together for life.

_____ 13. Shorebirds, such as ducks, geese, and swans, spend most of their time on the water surface.

_____ 14. Diurnal raptors are active during the night and sleep during the day.

_____ 15. Parrots are found in tropical regions and are very intelligent.

Name___________________ Class______________ Date________

Read these passages from the text and answer the questions that follow.

Structure and Function in Birds

Birds can vary considerably in size. The tiny bee hummingbird is just 5 centimeters (2 inches) long, whereas the ostrich towers over people at a height of 2.7 meters (9 feet). All modern birds have wings, feathers, and beaks. They have a number of other unique traits as well, most of which are adaptations for flight. Flight is used by birds as a means of locomotion in order to find food and mates and to avoid predators. Although not all modern birds can fly, they all evolved from ancestors that could.

Wings and Feathers

Wings are an obvious adaptation for flight. They are actually modified front legs. Birds move their wings using muscles in the chest. These muscles are quite large, making up as much as 35 percent of a bird’s body weight.

Feathers help birds fly and also provide insulation and serve other purposes. Birds actually have two basic types of feathers: flight feathers and down feathers. Flight feathers are long, stiff, and waterproof. They provide lift and air resistance without adding weight. Down feathers are short and fluffy. They trap air next to a bird’s skin for insulation.

Birds need a light-weight body in order to stay aloft. Even so, flying is hard work, and flight muscles need a constant supply of oxygen- and nutrient-rich blood. The organ systems of birds are adapted to meet these needs.

• Birds have light-weight bones that are filled with air. They also lack a jaw, which in many vertebrates is a dense, heavy bone with many teeth. Instead, birds have a light-weight keratin beak without teeth.
• Birds have air sacs that store inhaled air and push it into the lungs like bellows. This keeps the lungs constantly filled with oxygenated air. The lungs also contain millions of tiny passages that create a very large surface area for gas exchange with the blood.
• Birds have a relatively large, four-chambered heart. The heart beats rapidly to keep oxygenated blood flowing to muscles and other tissues. Hummingbirds have the fastest heart rate at up to 1,200 times per minute. That’s almost 20 times faster than the human resting heart rate!
• Birds have a sac-like structure called a crop to store and moisten food that is waiting to be digested. They also have an organ called a gizzard that contains swallowed stones. The stones make up for the lack of teeth by grinding food, which can then be digested more quickly. Both structures make it easier for the digestive system to produce a steady supply of nutrients from food.

Questions

1. What is flight used for in birds?

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2. Describe the two types of feathers found in birds.

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3. List three bird adaptations for flight.

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4. Describe the bird heart.

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5. What are a crop and gizzard? Describe their functions.

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Lesson 19.5: Multiple Choice

Name___________________ Class______________ Date________

Circle the letter of the correct choice.

1. Birds
1. have eggs with hard, calcium carbonate shells.
2. lay amniotic eggs.
3. are bipedal.
4. all of the above
2. Adaptations for flight in birds include
1. air sacs that store inhaled air and push it into the lungs.
2. solid bones that are filled with air.
3. a relatively large, two-chambered heart.
4. all of the above.
3. A crop and gizzard
1. keep the lungs constantly filled with oxygenated air.
2. are both part of the bird's digestive process.
3. keep oxygenated blood flowing to muscles and other tissues.
4. are part of a light-weight keratin beak.
4. Courtship in birds may include
1. singing and dancing.
2. a display of bravery.
3. drinks and dinner.
4. all of the above.
5. Which of the following statements about incubation is true? In birds, incubation (1) keeps the eggs warm while the embryos inside continue to develop, (2) may be done by males, (3) is only done by females.
1. 1 only
2. 1 and 2
3. 3 only
4. 1, 2, and 3
6. Flightless birds include
1. ostriches.
2. penguins.
3. kiwis.
4. all of the above.
7. Birds probably evolved from
2. dinosaurs.
3. insects.
4. none of the above.
8. Which of the following statements are true of bird diets? (1) Some birds are generalists. (2) Vultures are scavengers. (3) Bird beaks are generally adapted for the food they eat. (4) Raptors such as hawks and owls are omnivores.
1. 1 and 2
2. 2 and 3
3. 1, 2, and 3
4. 1, 2, 3, and 4

Lesson 19.5: Vocabulary I

Name___________________ Class______________ Date________

Match the vocabulary word with the proper definition.

Definitions

_____ 1. the most numerous vertebrates on Earth

_____ 2. an organism that can eat many different types of food

_____ 3. the process of keeping eggs warm with body heat

_____ 4. a sac-like structure that stores and moistens food

_____ 5. birds whose flight tends to be brief and close to the ground

_____ 6. they hunt by sight and have excellent vision

_____ 7. can hunt with their sense of hearing alone

_____ 8. contains swallowed stones that grind food

_____ 9. modified front legs adapted for flight

_____ 10. behavior that is intended to attract a mate

_____ 11. are very intelligent

_____ 12. trap air next to a bird’s skin for insulation

_____ 13. provide lift and air resistance without adding weight

_____ 14. have webbed feet and are good swimmers

_____ 15. considered to be one of the closest non-bird relatives of modern birds

Terms

a. birds

b. courtship

c. crop

d. Deinonychus

e. diurnal raptors

f. down feathers

g. flight feathers

h. generalist

i. gizzard

j. incubation

k. landfowl

l. nocturnal raptors

m. parrots

n. waterfowl

o. wings

Lesson 19.5: Vocabulary II

Name___________________ Class______________ Date________

Fill in the blank with the appropriate term.

1. ____________ are an obvious adaptation for flight.

2. ____________ feathers provide lift and air resistance without adding weight.

3. ____________ feathers trap air next to a bird’s skin for insulation.

4. Birds have a sac-like structure called a ____________ to store and moisten food.

5. Birds have light-weight ____________ that are filled with air.

6. ____________ in birds may involve singing specific courtship song.

7. Deinonychus is an extinct ____________ that is one of the closest non-bird relatives of modern birds.

8. Flightless birds have long legs and are adapted for ____________.

9. During ____________, birds keep their eggs warm with their body heat while the embryos inside continue to develop.

10. Eggs are usually laid in a ____________.

11. In birds, the part of the brain that controls ____________ is the most developed part.

12. Predatory birds, such as hawks, have especially good ____________.

Lesson 19.5: Critical Writing

Name___________________ Class______________ Date________

Thoroughly answer the question below. Use appropriate academic vocabulary and clear and complete sentences.

Describe how birds reproduce and care for their young.

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Date Created:
Feb 23, 2012