DINOSAURS: Why They Disappeared

CHAPTER 13

DINOSAURS: Why They Disappeared

I. PRELISTENING

A. Listening Preparation

The word "dinosaur" means terrible lizard. About 150 million years ago, dinosaurs roamed the earth. There were many kinds of dinosaurs. Some of the dinosaurs were as small as chickens, while other dinosaurs were as large as houses. Dinosaurs were very successful animals on the earth for millions of years, but there are no dinosaurs on the earth today. Dinosaurs are extinct. They have been extinct for 65 million years. What happened to these animals that had lived so successfully on the earth for millions of years? Why did they become extinct? No one can be absolutely sure, of course. Many theories have been proposed since scientists began to take an interest in the fate of these incredible creatures.

In this talk you will hear about two current theories explaining why the dinosaurs disappeared from the earth. The theories are (1) the climatic change theory; and (2) the asteroid or comet theory. Listen as these two theories are explained to you.

B. Preview of Vocabulary and Sentences

to propose a theory - to suggest an explanation for why something happens; an explanation based on observation and reasoning

• Several theories have been proposed about why the dinosaurs disappeared from the face of the earth.

to become extinct - to have disappeared from the face of the earth

• One theory says that climatic changes caused the dinosaurs to become extinct.

severe very serious; grave

• The cold weather finally resulted in a severe shortage of food for the dinosaurs.

to dwindle - to decrease in amount; to lessen

• The dinosaurs disappeared gradually as the earth became colder and as their food supply dwindled.

evidence - an outward sign of the truth or falsehood of something

• Today there is new evidence that the dinosaurs did not disappear gradually but that they disappeared quickly and suddenly.

asteroid - one of the thousands of small planetlike bodies that revolve around the sun

· This theory is known as the asteroid theory.

comet - a heavenly body made up of ice, frozen gases, and dust particles. It has a bright head and a long tail of light.

The asteroid theory states that a huge asteroid, or perhaps a comet, hit the earth about 65 million years ago.

to block out the sun - to prevent the light of the sun from reaching the surface of the earth

• The huge dust cloud covered the whole earth and blocked out the sun for months.

rare earth element - one of the uncommon substances, such as plutonium, that is composed of atoms that are all chemically alike

• Scientists recently found large amounts of the rare earth element called iridium all over the world.

layer of the earth - one thickness of the earth

• Iridium was found in layers of the earth that are 65 million years old.

to speculate - to make a guess based on an observation and some evidence

• Scientists speculate that this iridium was brought to earth 65 million years ago when a comet or asteroid hit the earth.

to debate - to give reasons for and against; to argue formally for or against

• Today scientists debate the two theories: the climatic change theory and the asteroid theory.

lizard - a reptile with four legs, a long tail, and a scaly body

In the future new evidence may be found that supports a totally new theory of why the terrible lizards died out.

C. Rhetorical Listening Cues

In this talk the speaker discusses two possible causes of the dinosaurs' disappearance from the earth. The speaker will use some words and phrases which signal causes and/or effects. The speaker will use words and phrases such as "was caused by," "since," "why," "caused," and "resulted in."

II. LISTENING

A. Initial Listening

Now let's listen to a talk about the extinction of the dinosaurs. It may help you to concentrate on the talk if you close your eyes while you listen. Just relax and listen carefully.

B. Mental Rehearsal and Review of the Talk

Let's listen to the talk once again. This time, the talk will be given in message units. Please repeat each unit to yourself silently after you hear it. Remember, don't say the units out loud.

С. Consolidation

You will hear the talk given once again. As you listen to the talk, take notes on what you hear.

III. POSTLISTENING

A. The Comprehension Check

1. Recognizing Information and Checking Accuracy

For questions 1-4 you will hear multiple-choice questions about the information presented in the talk. Listen to each question and decide whether (a), (b), (c), or (d) is the best answer to the question.

______ 1. Dinosaurs ______.

(a) were vegetarians

(b) may disappear from the earth some day

(c) were successful animals for millions of years

(d) disappeared from the earth sometime in the past

______ 2. The dinosaurs died out ______.

(a) from breathing too much dust

(b) from eating too much iridium

(c) because an asteroid or a comet hit them

(d) because their food supply was destroyed

______3. (a) Dinosaurs disappeared quite suddenly.

(b) Dinosaurs disappeared gradually and slowly.

(c) A comet hit the earth 150 million years ago.

(d) An asteroid or comet hit the earth 65 million years ago.

______4. Both theories state that______.

(a) climatic change killed the dinosaurs

(b) a food shortage caused dinosaurs to become extinct

(c) an asteroid or a comet hit the earth 65 million years ago

(d) there is no evidence which could explain why the dinosaurs disappeared

For questions 5-10, you will hear six statements about ideas. If the speaker mentioned the idea in the talk, put a check in the box "/ heard this idea in the talk." If, however, the idea was not mentioned in the talk, but you could infer the idea from the information given in the talk, put a check in the box, "I didn't hear this idea but can infer it from the information given." Finally, if the idea you hear was not mentioned, and could not be inferred from the talk, check the box "I did not hear this idea in the talk and cannot infer it from the information given."

	I heard this idea in the talk	I didn’t hear this idea but can infer it from the information given	I did not hear this idea in the talk and cannot infer it from the information given
5.
66.
77.
88.
99.
10.

Now, you create four statements about the talk yourself. Ask a classmate to listen to the statements and to complete the chart below.

	I heard this idea in the talk	I didn’t hear this idea but can infer it from the information given	I did not hear this idea in the talk and cannot infer it from the information given
111.
112.
113.
114.

2. Using and Expanding on the Information in the Talk

a. Recapping the Information from Your Notes. Use your notes to recap the information you learned about theories related to the extinction of dinosaurs. Present the information to the class or to one of your classmates.

b. Expanding on the Information in the Talk. Discuss with a classmate why you agree (or do not agree) with the following statements:

1. It's important for scientists to keep trying to figure out why dinosaurs disappeared.

2. We shouldn't worry so much about modern animals that are threatened with extinction since it's natural for animals to become extinct.

3. There is no danger today that an asteroid will hit the earth.

4. Human beings might become extinct someday.

В. The Listening Expansion

Task 1. Recognizing Possible Causes of a Situation

You will listen to a description of ten situations. After you listen to each situation described, read the four choices (a), (b), (c), and (d) and select the possible cause or causes of each situation.

For example, you will hear this situation described: "John has a broken leg." What are some possible causes of his broken leg? You will read in your book:

_______ (a) John can’t drive his car.

_______ (b) John was in a car accident.

_______ (c) John left work early today.

_______ (d) John went skiing last weekend and fell.

John's leg might be broken because: (b) He was in a car accident. (That's possible.) Or (d) He went skiing last weekend and fell. (That's possible, too.) Choices (a) and (c) do not have anything to do with the possible cause of John's problem. Remember, find the possible cause or causes of a situation you hear described. Are you ready to begin?

1. _______ (a) The set is broken.

_______ (b) The set isn’t plugged in.

_______ (c)The telephone is ringing.

_______ (d) You forgot to pay your electricity bill.

2. _______ (a) The park is near her house.

_______ (b) She doesn’t feel very well.

_______ (c) The weather is warm and sunny.

_______(d) She has to study for an exam.

3. _______ (a) The weather wasn’t clear.

_______ (b) The spaceship exploded on lift-off.

_______ (c) One of the astronauts became sick.

_______(d) There was a problem with the computer on the spaceship.

4. _______ (a) He was often late to work.

_______ (b) He found a new job immediately.

_______ (c) He was sometimes rude to the customers.

_______(d) He doesn’t have enough money now to pay the bills.

5. _______ (a) He grew up in Paris.

_______ (b) He liked living in Paris.

_______ (c) He went to Paris to get a job.

_______(d) His parents lived there in the 1040s.

6. _______ (a) The teacher didn’t like Mary.

_______ (b) Mary didn’t study for an exam.

_______ (c) The examination was too difficult for the class.

_______(d) Mary didn’t understand the directions to the test.

7. _______ (a) Your doctor is out of town.

_______ (b) You have dialed a wrong number.

_______ (c) Nobody is in the doctor’s office.

_______(d) The doctor’s phone is out of order.

8. _______ (a) John was unlucky when he gambled.

_______ (b) It’s very expensive to fly to Monte Carlo.

_______ (c) John doesn’t have enough money to get home.

_______(d) John doesn’t like to lose money when he gambles.

9. _______ (a) John didn’t have a good job.

_______ (b) John had married another woman.

_______ (c) John was killed in a traffic accident.

_______(d) Mary realized that she didn’t love John.

10. _______ (a) He is a soccer player.

_______ (b) He is going to play tennis.

_______ (c)He is getting ready to go jogging.

_______(d) He has just finished to play volleyball.

Task 2. Predicting the Ending of a Story: Stating the Possible Results

You will listen to five stories. None of the stories has an ending. You will supply the ending. You will tell what happened in your own words. Tell the ending of each story to your teacher or to a classmate. Use your imagination to complete the story.

1. It's a cold and snowy night. (Listen.)

2. It's the last half of a championship soccer game. (Listen.)

3. A man is walking along the river. (Listen.)

4. You and your friend Bob are sitting in the movie theater waiting for the movie to begin. (Listen.)

5. You are waiting in line at the bank to cash a check. (Listen.)

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