全新版大学英语-视听阅读4-答案
Unit 1 The Perfect Swarm Unit 2 The Red Devils Unit 3 The Orient Express
Unit 4 The Varied Cultures of China Unit 5 Afghanistan's Heroic Artists
Unit 6 Natacha's Animal Rescue Unit 7 Firewalking Unit 8 Living in the Slow Lane Unit 9 Alternative Energy Unit 10 Mars on Earth
Glossary
Unit 1
This story is set in the central and western U.S., particularly in the states of Texas, Oklahoma, Kansas, Nebraska, North and South Dakota, and Wyoming as well as the Rocky Mountains.
In the 1800s, the Rocky Mountain locust brought massive destruction to Western settlers. Then, the insects suddenly disappeared almost without a trace. Now scientists hope to find a reason for the locust's extinction. What caused the Rocky Mountain locust to disappear? Where will the scientists find the answers?
I. Locusts! Read the paragraph. Then match each word with the correct definition.
Many places in the world regularly experience plagues of locusts that can devastate entire countries. Locusts move in huge swarms, invade entire regions, and usually consume everything in their path. One swarm of locusts containing trillions of individual insects can eat thousands of tons of vegetation a day. Locusts are one of the world's most destructive insects, but they themselves are sometimes destroyed. In the 1800s, for example, the Rocky Mountain locust mysteriously became extinct.
1. plague ___E___
2. locust ___G___
3. devastate ___C___
4. swarm ___E___
5. trillion __A____
6. vegetation __F____
7. extinct ___B___
A. 1,000,000,000,000
B. no longer in existence
C. cause extreme damage
D. any widespread cause of misery, suffering, or death
E. a large group, usually of insects
F. the plant covering an area
G. an insect noted for flying in large groups and destroying crops
II. The Rocky Mountain Locust Mystery. Read the paragraph. Then complete the definitions with the basic form of the underlined words or phrases.
Dr. Jeff Lockwood is an entomologist who is particularly interested in the disappearance of the Rocky Mountain locust. The species was mysteriously wiped out in the late 1800s and there aren't many clues as to why it happened. By studying locust specimens under a microscope and by taking DNA samples from the dead locusts, Lockwood aims to find out why the Rocky Mountain locust suddenly disappeared from Earth.
1. a thing or fact that helps provide an answer to a question; evidence: clue
2. a person who studies insects: entomologist
3. an item that is an example of a larger group: specimen
4. destroy completely; cause to no longer exist: wipe out
5. a scientific instrument that uses lenses to make small objects appear larger: microscope
6. the material that carries the genetic information in the cells of each living thing: DNA SUMMARY
The mystery of the Rocky Mountain locust has baffled scientists in North America for over 100 years. After locusts completely devastated many parts of the United States in 1875, the entire species vanished from the continent. Entomologist Jeff Lockwood is determined to solve this mystery. After traveling to the Rocky Mountains and studying locusts frozen in glaciers, Lockwood begins to look at the mystery from a new angle.
Warming up
Teaching NOTES
1. Show students some pictures of locusts from the reading passage or other sources you can find.
2. Have students guess why the locusts in this video and the reading passage are called the perfect swarm.
3. Ask questions like “ Have you ever seen a locust?” and “ What do you know about locusts?”Grasshopper
There are hundreds of species of grasshoppers. These insects belong to the suborder Caelifera in the order Orthoptera, and have antennae that are almost always shorter than their bodies, and short ovipositors—organs for laying eggs. Normally females are larger than males. Males have a single unpaired plate at the end of the abdomen. The two pairs of valves (triangles) at the end of the female abdomen are used to dig in sand by the female grasshopper when laying eggs. Although they differ in many features, they are easily confused with another sub-order of Orthoptera, Ensifera. The main distinguishing elements are the number of segments in their antennae and structure of the ovipositor. The location of the tympana and modes of sound production are other distinguishing features. Ensiferans have antennae with at least 20—24 segments, and Caeliferans have fewer.
Butterfly
Like other holometabolous species with a complete metamorphosis where the immature insects are entirely different from the mature stages, butterfli es’ life cycle goes through four stages: egg, larva, pupa and adult. Their wings are large, often brightly colored, and they have conspicuous, fluttering flight.
Butterflies comprise the true butterflies, the skippers and the moth-butterflies. The very many other families within the order Lepidoptera are considered moths. Some butterflies migrate over long distances. Some have formed symbiotic and parasitic relationships with social insects such as ants. Butterflies are important economically as agents of pollination. A few species are pests because they can damage agricultural crops or trees in their larval stages.
Culturally, butterflies are featured in the visual and literary arts.
Dragonfly
A dragonfly is an insect characterized by big multifaceted eyes, two pairs of strong transparent wings, and an elongated body. Dragonflies and damselflies are similar in appearance.They differ in the position of their wings which are held away from, and perpendicular to, the body when at rest. Like any other insects, dragonflies possess six legs, but are not able to walk.
Dragonflies usually eat flies, bees, ants, butterflies, and other small harmful insects, and are valuable as predators who help keep the equilibrium between beneficial insects and pests.They us ually live around lakes, ponds, streams and wetlands because their larvae, known as “nymphs”, are aquatic.
Cricket
Partially related to grasshoppers, crickets are another group of insects with long antennae and flattened bodies. They have good vision and hearing. Their compound eyes enable them to see in several directions simultaneously. A large number of crickets do not fly because their wings are not fully developed, but lie across the back. Their ability to jump to great heights compensates for the lack of flying skills. Crickets normally live less than one year. In the spring, the nascent insect hatches and looks like the adult, except for the wings. Only after shedding the skin several times do crickets develop new wings.
Although not all kinds of crickets are pests, some species such as the black field cricket can affect crops and gardens. They can also attack dwellings in autumn. The pale green tree cricket can destroy twigs and berry canes.
In some cultures, it is said that crickets bring good luck. Some people believe that all those who are fortunate enough to hear their songs are blessed. If a cricket lives in the house, it is treated with respect. They are placed in small cages and given food and water as the inhabitants of the house think that their existence brings good fortune.
Watching
video SCRIPT
Narrator: Damage from swarms of locusts can reach disastrous proportions. A single swarm of desert locusts can consume over 70,000 metric tons of vegetation a day. There is, however, one cont inent that’s locust-free: North America.
Interestingly enough, this wasn’t always true. For hundreds of years, the Rocky Mountain locust was a common pest in the American West. Back in the mid-1800s, thousands of pioneers
journeyed across the U.S. in search of free land and new opportunities. They settled on the frontier of the western states, and began to farm the land intensively, growing corn and other crops.
Then, in 1875, out of nowhere, a rare combination of air currents, drought, and basic biology produced the right conditions for an unthinkable event, the worst storm ever recorded, the “perfect swarm.” It came over the horizon like a strange, dark cloud. Not millions, not billions, but trillions of insects, sweeping through the land like a living tornado. Those who saw the incredible event and survived never forgot what they witnessed.
The swarm came together over the state of Texas, and soon moved quickly across the frontier in a huge destructive cloud that was nearly 3,000 kilometers long. The storm spread north towards North Dakota. The locusts eventually went as far west as the Rocky Mountains, leaving a path of devastation and destruction wherever they went.
An account from one person who observed the swarm described the locust storm. The locusts came down from the sky like hail. Frightened people ran screaming into their homes as the locusts’ claws dug into their skin and hung upon their clothing. They heard sharp cracks as the insects came underfoot. The large locusts were everywhere, looking with hungry eyes turning this way and that. Their bodies blocked the sun, bringing darkness along with the destruction.
Crop damages were absolutely astonishing. If such destruction were to happen today it would cost an estimated US$116 billion, more than the most costly hurricane in American history. And then, something remarkable happened: the Rocky Mountain locust simply vanished.
At the University of Wyoming, entomologist Dr. Jeff Lockwood has spent over a decade investigating why the Rocky Mountain locust disappeared.
Dr. Jeff Lockwood, University of Wyoming: “There were probably more locusts in the largest swarm than there are stars in the Milky Way — trillions. Not only is something of that scale and magnitude and power gone, but it’s gone within a few years. It’s not as if we had a tremendous series of earthquakes or tidal waves or forest fires. And so it doesn’t make sense that it could’ve gone extinct. There’s no reason for it to have done so. It’s a great mystery.”Narrator: It’s a mystery that Lockwood is determined to solve. Whatever wiped out the Rocky Mountain locust changed American history. Exactly what could have destroyed a plague nearly 3,000 kilometers long? Lockwood is on the case. He starts the investigation with the victim itself. Unfortunately, very few locust specimens exist, and those that do are often in bad condition. Dr. Lockwood: “So what we have is a body of evidence of the victim in its dying moments, alright, but we don’t know what the life of the victim looked like when it was flourishing. The next opportunity we have for a major set of clues is locked up in the ice of the glaciers of the Rocky Mountains.”
Narrator: Lockwood is headed to Knife Point Glacier, Wyoming, not far from Yellowstone National Park. For centuries, strong winds would sweep swarms of locusts high into the mountains, where they would freeze to death.
Dr. Lockwood: “These glaciers serve as both traps and sort of icy tombs for the Rocky Mountain locust. Were we looking at a long, slow death, or were we lo oking at a sudden demise?”Narrator: By extracting DNA samples from specimens frozen over a period of time, Lockwood may be able to specify exactly what caused the extinction of the insects. The good news for the expedition is that there could be locust s pecimens anywhere, but the bad news is that “anywhere” includes thousands of square meters covered with snow and ice. Then, on one of the steeper parts of the mountain, Lockwood sees something.
Dr. Lockwood: “Check it out!”
Lockwood’s Colleague: “A whole body?”
Dr. Lockwood: “It looks like it.”
Lockwood’s Colleague: “Head, thorax, and abdomen?”
Dr. Lockwood: “Look, you can see the wings.”
Narrator: Lockwood will take the locusts back to his laboratory to examine them more closely. If they’re the right spec ies, they could help solve one of the greatest extinction mysteries of our time.
Dr. Lockwood: “To get my hands on the body, in terms of this murder mystery, was critically important.”
Narrator: A look under the microscope reveals the signs.
Dr. Lockwood: “At that moment, I knew that we had the Rocky Mountain locust.”
Narrator: It’s an exact match. They’re the same species of locusts that once devastated the American plains. Lockwood’s study of the Rocky Mountain locust has told him more and more about this odd insect. They seem to have split personalities. On one hand, as members of the grasshopper family, they’re generally shy and remain alone. But when annoyed in just the right way, the once gentle locust changes completely into some kind of destructive monster. They change color and their wings and legs grow longer. Eventually, they become more aggressive and swarm, whereby they become a kind of living, breathing weapon of mass destruction.
Dr. Lockwood: “Nobody’s in charge. There’s no leader, there’s nobody out in front.”Narrator: Back in the laboratory, the locusts are revealing their secrets. The DNA test results are back and they’ve indicated one certain fact: the Rocky Mountain locust didn’t decline over a long period of time.
Dr. Lockwood: “It was not sort of a death by old age. In fact, what we’re looking at is a very sudden sort of ‘bolt out of the blue’ disappearance. There’s nothing in the genetic course of this species that would lead us to believe that it was in its last days.”
Narrator: Some other force must have been responsible for destroying the plague, and Lockwood is determined to find it.
Dr. Lockwood: “I began to realize that we’ve been looking at the wrong scale. If we want to find out perhaps what eliminated the Rocky Mountain locust, what we should be looking for is what was happening to the species at the time of its weakest link.”
Narrator: Now, after years of research, Lockwood may finally be able to solve the mystery of why the Rocky Mountain locust disappeared. It turns out that the Rocky Mountain locust gathered in one particular region to lay its eggs. In the 1800s, that region was in the river valleys of the Rocky Mountains.
Dr. Lockwood: “It turned out that agriculture was booming in these river valleys in the late 1800s.”
Narrator: The gold and silver industries were booming as well. The major nesting area of the rocky Mountain locust had become a busy and overcrowded place; therefore, conditions there would certainly have had an effect on any species.
Dr. Lockwood: “The killer of the Rocky Mountain locust turns out to be us. The pioneer agriculturalist of the Rocky Mountain West in the late 1800s is the killer of the Rocky Mountain locust.”
Narrator: As farms appeared in the river valleys to feed the miners, the farmers plowed up the fields and stamped out the delicate eggs that had been laid by the great swarm. By not allowing the eggs to mature into full-grown locusts, the species was entirely destroyed at its weakest —when the insects were just eggs. The only extinction of a pest species in agricultural history was in fact an accident.
Teaching notes
I. 1. Give students time to go through the statements.
2. Play the video.
3. Elicit the answers from students.
4. Have students discuss why the statements are true or false.
II. 1. Allow students some time to predict the answers.
2. Play the video.
3. Elicit the answers from students.
4. Have students summarize the main idea of this part.
III. 1. Explain how to conduct an interview.
2. Have students read the useful expressions.
3. Put students into pairs and have them discuss the interview questions and answers.
4. Have some pairs role-play their interviews to the class.
5. Give students some comments and suggestions for improvement.
Word bank
1. disastrous adj. causing great damage
A disastrous fire swept through the factory.
He made a disastrous mistake.
2. combination n. a number of separate things or people that are combined to form a
single unit or whole
A combination of drought and locusts forced people to leave their hometown.
3. destructive adj. causing great and irreparable damage
The storm could be destructive to the crops.
Useful expressions
Expressing surprise
* Oh, my!
* Incredible!
* Unbelievable!
* What a surprise!
* How could it be?
* I couldn’t believe my eyes.
Teaching notes
I. 1. Have students read the statements to get familiar with the ideas.
2. Play the video.
3. Elicit the answers from students.
II. 1. Give students time to predict the answers.
2. Play the video.
3. Elicit the answers from students.
III. 1. Have students read the useful expressions.
2. Put students into pairs and have them prepare the explanations.
3. Have some pairs present their explanations to the class.
4. Give students some comments and suggestions for improvement.
Word bank
1. investigate vt. try to find more information about
If you hear such a rumor, investigate it first.
It’s not easy to investigate such a mysterious case.
2. tremendous adj. very great in size, amount or degree
There was a tremendous series of forest fires.
He inherited a tremendous amount of money from his uncle.
3. specimen n. an individual animal, plant, etc. used as an example of its species or type for scientific study or display
They are in search of a special specimen of butterfly.
There are many specimens of copper ore in the lab.
Useful expressions
Expressing determination
* I have decided to...
* I’ve made up my mind to...
* He was determined to...
Teaching notes
I. 1. Give students time to predict the answers.
2. Play the video.
3. Elicit the answers from students.
4. Have them retell the activities carried out by Dr. Jeff Lockwood.
II. 1. Give students time to predict the answers.
2. Play the video.
3. Elicit the answers from students.
4. Have students ask and answer these questions in pairs.
III. 1. Have students repeat each sentence after it is spoken twice and then write the sentences.
2. Have students listen again, and mark the word stress on content words with a stress mark (?).
3. Have students listen to each sentence and draw an upward arrow ? for rising intonation, or a downward arrow ? for falling intonation.
4. Have students listen again and draw a curved line ? to mark any words that are linked or blended together.
5. Have students practice reading the sentences till they can say them using appropriate intonation and stress pattern.
Word bank
1. reveal vt. show or allow (something previously hidden) to be seen
He has successfully revealed the exact reason.
The DNA analysis reveals everything.
2. aggressive adj. always ready to quarrel or attack
The grasshopper turned out to be very aggressive.
The aggressive animal attacks anything that it meets.
3. eliminate vt. remove or get rid of completely
The government tried its best to eliminate poverty.
Teaching notes
I. 1. Give students time to predict the answers.
2. Play the video.
3. Elicit the answers from students.
II. 1. Give students time to predict the answers.
2. Play the video.
3. Elicit the answers from students.
III. 1. Have students read the useful expressions.
2. Put students into pairs and have them discuss the reasons, make comments and express their feelings.
3. Have some pairs present their discussion results to the class.
4. Give students some comments and suggestions for improvement.
Word bank
1. turn out happen to be or be found to be
It turns out that it's human beings who eliminated the Rocky Mountain locust.
She turns out to be the mother of the abandoned child.
Collocation
turn away 不准…进入
turn down 调低；拒绝
turn in 交还；获得
turn off 关掉
turn on 打开
turn to 转向；向……求助
2. boom vi. grow rapidly in activity, value or importance
The economy is booming.
California boomed when gold was discovered there.
3. delicate adj. needing careful handling, especially because easily broken or damaged
We need to be careful of the delicate vase.
Teaching notes
I. 1. Give students time to predict the answers.
2. Play the video.
3. Elicit the answers from students.
4. Have students summarize the main idea of the entire video.
I. 1. Have students read the useful expressions.
2. Put students into pairs and have them talk about the picture.
3. Have some pairs role-play their conversations in front of the class.
4. Give them some comments and suggestions for improvement.
III. 1. Put students into groups of three or four. Introduce the task.
2. Go through the information in the table.
3. Give students time to do the research, find the information and complete the table.
4. Invite a representative from each group to report to the class. Encourage groups to prepare PowerPoint presentations of their findings.
5. When a group is making a report, ask other groups to take notes.
6. After all the groups finish their reports, have students check their notes in their groups,
or summarize other groups’ findings.
I. Watch Part 1. Decide whether the following statements are true (T) or false (F).
____F__ This part focuses on the types of the Rocky Mountain locust.
____F__ Locusts exist on all continents.
____T__ An unbelievable event happened in 1875 when weather conditions helped to create t he "perfect swarm.”
____T__ The "perfect swarm caused extensive damage to the vegetation.
___F___ The worst storm disappeared in a few hours.
___T___ Locusts could hurt people physically and emotionally.
II. Watch again. Fill in the blanks with the missing information.
This part is mainly about the history and the present situation of the Rocky Mountain locust in (1) North America. In the mid-1800s, thousands of pioneers journeyed across the U.S. in search of (2) free land and (3) new opportunities. They settled on the frontier of the western states, and began to (4) farm the land intensively. Then, in 1875, there was a disaster caused by the a huge swarm of locusts. (5) Trillions of insects came together over the state of Texas, and flew quickly across the frontier in (6) a huge destructive cloud that was nearly (7) 3,000 kilometers long. The locusts (8) eventually went as far west as the Rocky Mountains, destroying everything (9) wherever they went. However, today people can't see any locusts in North America because the Rocky Mountain locust simply (10) vanished.
III. Oral work. Work with your partner. Make an interview between a news reporter and a person who witnessed the perfect swarm. Ask and answer questions about the disaster. The witness should try to explain and act out what he or she had seen, heard and felt.
Useful expressions
What did you see? What did you hear?
What did you do? Why did you run back to your home?
How did you feel? How about the other people?
Locusts
coming down from the sky like hail; looking with hungry eyes; turning this way and that; blocking the sun; bringing darkness; claws digging into their skin and hung upon their clothing …People
screaming into their homes; hearing sharp cracks as the insects came underfoot …
I. Watch part 2. Choose the true statements about the Rocky Mountain locust.
______ The Rocky Mountain locust died as a result of a tremendous series of earthquakes, tidal waves and forest fires.
____√__The extinction of locusts remains a mystery in the history.
______ The reason why the Rocky Mountain locust became extinct is not something Dr. Jeff Lockwood is interested in.
___√___There are few locust specimens and they are not in good condition.
___√___Strong winds would sweep swarms of locusts high into the mountains.
______ Locusts suffered a long and slow death.
______ Locusts suffered a sudden demise.
____√__The whole body of a locust is found in the ice.
II. Watch again. Answer the following questions in five words or less.
1. How many years has Dr. Jeff Lockwood spent on the mysterious phenomenon?
Over a decade.
2. What did the extinction of the Rocky Mountain locust change?
American history.
3. In what condition are the few locust specimens?
They are often in bad condition.
4. How would locusts die in the Rocky Mountain?
They would freeze to death.
5. Where did Dr. Lockwood find the locust specimen?
On one of the steeper parts of the mountain.
III. Oral work. Explain to your partner the reasons why Dr. Jeff Lockwood leads his team to the Rocky Mountain. Use the information you've learned in this part and the expressions below. Useful expressions
very few locust specimens exist and they are in bad condition
a body of evidence of the victim in its dying moments
what the life of the victim looked like when it was flourishing
a major set of clues is locked up in the ice
extracting DNA samples from specimens
specifying exactly what caused the extinction of the insects
I. Watch part 3. Put the following statements in the correct order.
A. Extract DNA samples.
B. Ensure the locusts they have are the right species.
C. Take the locusts back to the laboratory to examine them more closely.
D. Find signs that the locusts didn't die of old age.
E. Realize the importance of looking at the species at the time of its weakest link.
F. Conclude there must be some other force leading to the sudden death.
( C )→( B )→( A )→( D )→( F )→( E )
II. Watch again. Fill in the blanks in the table with the missing words.
How did they know they had the Rocky Mountain locust?
How do the locusts generally behave?
What do the locusts look like when they are annoyed?
What happens to their wings and legs when they are angry?
What fact does the DNA test indicate?
It was an exact match.
They're generally shy and remain alone.
They change completely into some kind of destructive monster.
They grow longer.
They didn't decline over a long period of time.
III. Listen and repeat. You are going to hear five sentences selected from the video. Repeat
each sentence after it is spoken twice. Then write the sentences.
1. To get my hands on the body, in terms of this murder mystery, was critically important.
2. They are the same species of locusts that once devastated the American plains.
3. Eventually, they become more aggressive and swarm, whereby they become a kind of living, breathing weapon of mass destruction.
4. There’s nothing in the genetic course of this species that woul d lead us to believe that
it was in its last days.
5. Some other force must have been responsible for destroying the plague.
I. Watch part 4. Choose the best answer to each of the following questions.
1. Where did the Rocky Mountain locust lay its eggs?
A. In the forest of the mountains.
B. On the top of the mountains.
C. In the river valleys of the mountains.
D. In the farm land near the mountains.
2. Which of the following is NOT mentioned as being prosperous in the late 1800s?
A. Silver industry.
B. Coal industry.
C. Gold industry.
D. Agriculture.
3. Who was mainly responsible for the extinction of the Rocky Mountain locust?
A. The farmers.
B. The miners.
C. Locusts themselves.
D. The government.
II. Watch again. Complete the following sentences with the missing words.
1. Now, after years of research, Lockwood may finally be able to solve the mystery of why the
Rocky Mountain locust disappeared.
2. The major nesting area of the Rocky Mountain locust had become a busy and overcrowded place.
3. By not allowing the eggs to mature into full-grown locusts, the species was entirely destroyed
at its weakest when the insects were just eggs.
III. Oral work. Describe to your partner the exact reason for the extinction of the Rocky Mountain locust. Then explain your feelings or make comments on this incident in American agricultural history.
Useful expressions
gather in one particular region gold and silver industries
the pioneer agriculturalist of the Rocky Mountain West
feed the miners plow up the fields
stamp out the delicate eggs What a pity it is!
That's too bad! It's just an accident.
No one should be blamed …
I. Watch the entire video. Choose the appropriate heading for each part.
Part 1 ___B___ A. Dr. Lockwood finds the Real Cause of the Rocky Mountain Locust Extinction
Part 2 ____C__ B. The Unthinkable Event in North America in the 1800s
Part 3 ____D__ C. Dr. Lockwood's Confusion about the Cause of the Extinction
Part 4 ____A__ D. Dr. Lockwood's Analysis and Introduction to Some Locust Facts
II. Oral work. Work with a partner. Describe the picture below. Use the information from the video and the expressions below.
Useful expressions
thousands of pioneers journeyed west
across the U.S. in their covered horse-drawn wagons
in search of free land
wide open spaces
new opportunities with their great expectation about their future life …
III. Project. Form groups of three or four. Each group does research online or in the library on a kind of insect. Then each group fills in the following table and reports the findings to the whole class.
Insects grasshopper butterfly dragonfly cricket bee moth beetle
How many types are there?
What does it look like?
Where does it live?
What does it live on?
What can it do?
What benefits or harms does it bring to human beings?
READING
The Perfect Swarm
1 In parts of the world, such as West Africa, the damage from the swarms of locusts that can plague an area often reach disastrous proportions. At times, countries are attacked by billions of locusts, which can easily invade entire regions, greedily eating everything in sight. A single swarm of desert locusts can consume over 70,000 metric tons of vegetation a day, enough to feed 200 million people.
2 Locusts are one of the world's most destructive insects, and for some, they bring to mind images of terror and destruction. These seemingly harmless insects can have a devastating effect on a country's food reserves when appearing in large numbers. These disaster-causing insects can live almost everywhere in the world so they affect a large number of people; however, there is one continent where locusts don't exist at all.
3 At the present time, North America is the only continent on Earth that isn't home to the locust but, interestingly enough, this wasn't always true. For hundreds of years, the Rocky Mountain locust was a very common pest in the American West, causing massive destruction to crops and costly disturbances to agricultural economies. However, in the late 1800s, an extremely odd phenomenon occurred involving the Rocky Mountain locust. It's a case that has been recorded several times in history by people who witnessed it, and without documentation, the event would seem almost unreal.
4 Back in the mid-1800s, thousands of pioneers journeyed west across the U.S. in their covered horse-drawn wagons in search of free land, wide open spaces, and new opportunities. They settled on the frontier of the western states, and began to farm the land intensively, growing corn and other crops. They struggled to earn a living from the soil and worked for days on end to break the earth into farmable fields using only horses, plows, and a lot of sweat.
5 Then in 1875, out of nowhere, a rare combination of air currents, drought, and basic biology produced the right conditions for an unthinkable event. It was the worst storm of its kind ever recorded: an enormous storm of locusts, the "perfect swarm. This huge mass of hungry insects came over the horizon like a strange, dark cloud. The cloud consisted of not millions, not even billions, but trillions of insects, sweeping through the land like a living tornado. Those who saw the incredible event and survived never forgot what they witnessed.
6 The swarm of locusts came together over the state of Texas, and soon moved quickly across the frontier in a huge destructive cloud that was nearly 3,000 kilometers long. When people saw the cloud appear in the sky, they were completely amazed, and then quite naturally became frightened. The farmers had never seen anything like the swarm before, and immediately began to run from the fields to their houses for shelter and safety.
7 The storm of locusts kept moving and spread north from Texas to the areas now known as Oklahoma, Kansas, Nebraska, and South and North Dakota. The locusts eventually went as far west as the Rocky Mountains, leaving a path of devastation and destruction wherever they went. Thousands of farmers and pioneers were caught off guard as the swarm moved in, warned only moments before its arrival by the low, sickening drone of a seemingly infinite number of hungry insects.
8 An account from one person who observed the locust swarm described the event as if it were an actual storm. According to the observer, the locusts came downward heavily like hail, making loud noises as they fell to the earth. Frightened people ran screaming in terror into their homes as the locusts claws? dug into their skin and hung upon their clothing. As they ran, they left the fruits of hours of hard labor behind them to be eaten by the mass of eating machines, and the crops and fields were soon under attack.
9 While making their escape, the pioneers stepped on the locusts, hearing a sharp crack as the insects came underfoot. But no single group of people could diminish the unbelievable numbers of this insect invasion. The large insects were everywhere, looking with hungry eyes turning this way and that. Their bodies blocked the sun as they streamed through the Midwest, bringing darkness along with destruction. For the farmers, it was hopeless; hardly anything could be saved.
10 The crop damages resulting from this "perfect swarm were absolutely astonishing, even by modern standards. If such destruction were to happen today it would cost an estimated $116 billion U.S., a sum that is even more than the most costly hurricane in American history. Several agricultural regions were devastated, both economically and emotionally. Agricultural commodities became scarce, crops were wiped out, and many of the pioneers simply packed up and left having lost everything to the swarm. And then, something remarkable happened: the Rocky Mountain locust simply vanished.
11 For over 100 years, the disappearance of the Rocky Mountain locust from the U.S. has been one of the biggest mysteries of the natural world. It's a highly unusual phenomenon for a species not to just diminish in numbers, but to actually vanish from the earth. The question of what exactly happened to the Rocky Mountain locust has become the subject of several researchers, and one man in particular has spent years of his life trying to solve the puzzle.
12 At the University of Wyoming, entomologist Dr. Jeff Lockwood has spent over a decade investigating exactly why the Rocky Mountain locust disappeared in the late 1800s. He describes what the swarm of Rocky Mountain locusts was like and attempts to help the people visualize the huge numbers of locusts that made up the swarm."There were probably more locusts in the largest swarm than there are stars in the Milky Way trillions, he reports.
13 Lockwood goes on to pose the question of why the locust became extinct, commenting that the usual straightforward reasons for extinction don't seem to be present in this case. "Not only is something of that scale and magnitude?and power gone, but it's gone within a few years, he says. He then points out that no unusual events coincided with the commencement of the disappearance. "It's not as if we had a tremendous series of earthquakes or tidal waves or forest fires. And so it doesn't make sense that it could've gone extinct. There's no reason for it to have done so. It's a great mystery. It's also a mystery that Lockwood is determined to solve.
14 Whatever wiped out the Rocky Mountain locust changed the course of American history. Exactly what could have triggered the disappearance of the locust, thereby destroying a plague nearly 3,000 kilometers long? Lockwood is studying the case very carefully. He realizes that he needs to start the investigation with the victim itself the locust. Unfortunately, very few locust specimens exist, and those that do exist are often in bad condition. The specimens that Lockwood has been able to locate have provided him with some evidence, albeit minimal, of what could have wiped out the species, but he still needs more information.
15 In his laboratory, Lockwood regularly inspects the locust specimens for any additional clues that might lead to the solution of the mystery. Even though he can see what the insect is like when it's dead, he still doesn't know what it was like when it was alive. "So what we have is a body of evidence of the victim in its dying moments, alright, he explains, "but we don't know
what the life of the victim looked like when it was flourishing. Lockwood is in need of more clues about the life of the locust if he's going to unlock this mystery.
16 Eventually, Lockwood decides that a trip to the Rocky Mountains might help him to refine his theories. Since it is a region where Rocky Mountain locust specimens are likely to be preserved in ice, Lockwood feels that it might be the best place to find more information as to what brought about the demise of the species. "The next opportunity we have for a major set of clues , the
e ntomologist says, "is locked up in the ice o
f the glaciers of the Rocky Mountains.”
17 For Lockwood, the ice up in the Rockies might contain more than a few secrets and hopefully some answers. However, there's no guarantee that the mountains will provide any more information than what he already knows. It's a huge area to cover, and the average size of a locust specimen is just a few centimeters; the scientist may not even find any samples to examine, but he'll never know if he doesn't try.
18 Lockwood and a few of his colleagues head to the western state of Wyoming and ride on horseback to Knife Point Glacier, which is located not far from Yellowstone National Park. The scenery on the route up is magnificent; they're surrounded by rolling hills leading up to incredibly beautiful snow-covered peaks. But the group is not there to admire the landscape. The reason for their trip is a scientific one: it's their chance to hunt for frozen locusts.
19 For centuries, even before the "perfect swarm of 1875, year after year strong winds would sweep swarms of locusts high into the mountains, where they would freeze to death. As a result, the glacier is full of locusts that have been frozen in time. Lockwood explains, "These glaciers serve as both traps and sort of icy tombs for the Rocky Mountain locust. He then goes on to pose the key question to solving the mystery and what he wants to know: "Were we looking at a long, slow death, or were we looking at a sudden demise? By extracting DNA samples from specimens frozen over a period of time, Lockwood may be able to identify exactly what caused the extinction of the insects. Through this analysis he may be able to compile enough data to prove what wiped out the species, but first he has to find some of these mysterious frozen insects.
20 Lockwood and the team's route take them high into the mountains; eventually, the incline becomes too steep for the horses and they can no longer be ridden. Their journey must continue on foot. The entomologist and his colleague start to walk up into the high mountains, hiking slowly through the ice and snow until they get out onto the glacier. As they walk, the two men search for any signs of the locusts.
21 The good news for the expedition is that there could be locust specimens anywhere. The bad news is that "anywhere includes thousands of square meters covered with snow and ice. Walking up on the glacier is beautiful, the air is clear and the sun is shining. However, the trip is extremely exhausting in the thinning mountain air and the men begin to become tired from their efforts. They continue walking for a long time with no luck at finding locusts. The beautiful day turns to one of disappointment as the men's visions of finding a field of locust specimens begin to fade.
22 Then, suddenly, on one of the steepest parts of the mountain, Lockwood finally sees the perfect spot in which locusts might be found. He uses a pick ax to break into the ice and is rewarded handsomely for his efforts. As he breaks away the last stubborn piece of ice cover, he finds himself looking at an entire layer of ice filled with specimens and they're in nearly perfect condition. As he reaches in to carefully pull out one of the small, dark objects, Lockwood's colleague wants to confirm what the object appears to be. "A whole body? he asks cautiously. To this Lockwood responds with a sigh of relief, "It looks like it, as he continues examining the small age-darkened insect.
23 The locust specimen that Lockwood found is complete. The head, thorax, abdomen, and even the wings have been preserved. "Amazing, says Lockwood's colleague, as Lockwood puts the locust into a special container. He'll take the locust back to his laboratory to examine it more carefully under a microscope, in the hope that it will provide clues.
24 Before he returns to camp, though, Lockwood searches in the ice more carefully, eventually uncovering more insects using a small instrument. The two men are amazed at what they find. There are hundreds and hundreds of the locusts in this one place. It soon becomes clear that, in the shadow of the melting glacier, they've made an important find: piles of frozen locusts. This could be just what Lockwood has been hoping for. If the locusts that Lockwood has found in the glacier are the right species of insect, the entomologist hopes he can solve one of the greatest extinction "murder mysteries of our time. He explains, "To get my hands on the body, in terms of this murder mystery, was critically important.”
25 Back at the base camp of the expedition, the scientist uses a microscope to take a closer look at the insect found in the glacier. He realizes excitedly that he's found what he's been looking for. It's an exact match to his specimens of the Rocky Mountain locust. They are the same species of locusts that once devastated the American plains. Later, Lockwood describes the experience, "At that moment, I knew that we had the Rocky Mountain locust. The mystery of the disappearance of the Rocky Mountain locust may be well on its way to being solved.
26 Lockwood's study of the Rocky Mountain locust has told him more and more about this odd insect. Locusts seem to have "split personalities, he says. On the one hand, as members of the scientific family of the grasshopper, they are like all grasshoppers, which means they have a tendency to be shy and remain alone. On the other hand, when annoyed in just the right way, the once gentle locust changes completely into some kind of destructive monster. They change color and their wings and legs grow longer. Eventually, they become more aggressive and swarm, whereby they become a kind of living, breathing weapon of mass destruction. Members of the swarm behave as if they were one body with no leader. "Nobody's in charge, explains Lockwood. "There's no leader, there's nobody out in front. While swarming, the trillions of locusts function as one individual unit.
27 Back in the laboratory, the locust specimens that Lockwood found on the Knife Point Glacier are slowly revealing their secrets. The DNA test results are back and they've indicated one certain fact: the Rocky Mountain locust did not decline over a long period of time. In fact, the disappearance was very sudden. "It was not sort of a death by old age, says Lockwood. "In fact, what we're looking at is a very sudden sort of 'bolt out of the blue disappearance. Having finally had the chance to examine the species health over a period of time, Lockwood's evidence leads to this conclusion: "There's nothing in the genetic course of this species that would lead us to believe that it was in its last days. If it wasn't a gradual extinction or some inherent imperfection within the species, some other force must have been responsible for destroying it, and Lockwood is determined to find out what it was.
28 As Lockwood works to solve the problem of exactly what caused the extinction of the Rocky Mountain locust, he comes to an important realization. In order to discover the truth about what happened to the locust, he will have to look at what was happening to it when it was at its weakest, or most at risk, not when it was flourishing. "I began to realize that we've been looking at the wrong scale, he says. "If we want to find out perhaps what eliminated the Rocky Mountain locust, what we should be looking for is what was happening to the species at the time of its weakest link. Now, after years of research, Lockwood is closer than ever to solving the mystery of why the Rocky Mountain locust disappeared.
29 Lockwood begins by carefully examining maps of where the locusts lived during the 1800s, and where they bred at that period in time. It turns out that the Rocky Mountain locust gathered in one particular region to lay its eggs. In the 1800s, that region was in the river valleys of the Rocky Mountains. At the same time, the area's farming and agriculture industries were becoming more and more successful, and farms were beginning to appear everywhere. "It turned out that agriculture was booming in these river valleys in the late 1800s, explains Lockwood. However, that wasn't all that was happening. Concurrently, the gold and silver industries were booming as well, which resulted in more and more people settling in the area to service the mining communities. The major nesting area of the Rocky Mountain locust had become a busy and overcrowded place; therefore, the conditions there would certainly have had an effect on any species.
30 As Lockwood examines all the evidence, it finally begins to become clear to him exactly what happened. As a result, he is able to put forward a valid theory. He explains that it was humans who were in fact responsible for the extinction of the Rocky Mountain locust. "The killer of the Rocky Mountain locust turns out to be us, he says. "The pioneer agriculturalists of the Rocky Mountain West in the late 1800s were the killers of the Rocky Mountain locust. By investigating the conditions surrounding the locust at its weakest point, just upon hatching, Lockwood was able to solve the mystery that had puzzled scientists for over a century.
31 Lockwood explains exactly how the farmers unknowingly managed to wipe out the Rocky Mountain locust. As more and more farms appeared in the river valleys to feed the miners, the farming became more and more intensive. In the course of working on the land, the farmers plowed up the fields and thereby stamped out the delicate eggs that had been laid by the great swarm. Inside those unhatched eggs was the last generation of the Rocky Mountain locust. By not allowing the
eggs to mature into full-grown locusts, the species was entirely destroyed when it was at its weakest when the insects were just eggs. The only extinction of a pest species in agricultural history was in fact an accident.
pest n. an insect that causes destruction or annoyance
pioneer n. one of the first people to enter new or undeveloped land to live and work there plow n. a special farm implement used to turn over earth for planting crops
drought n. a period of little or no rainfall
drone n. a low, rhythmic sound
hail n. rain that freezes and falls as balls of ice
claw n. one of the sharp nails on an animal’s foot
vanish vi. completely and unexpectedly disappear
Milky Way the area of more than 100 billion stars in which our Sun and Earth are located magnitude n. great size
flourishing adj. doing well; healthy
demise n. end or death
glacier n. a large mass of ice that slowly moves, usually down a mountain
tomb n. a place where dead bodies are buried
pick ax a cutting tool with a sharp metal head on a long wooden handle
grasshopper n. a plant-eating insect that can jump high and that makes a loud noise
bolt out of the blue a sudden event
breed vi. have young
booming adj. very busy; doing well
hatch vi. come out of an egg
Reading Comprehension
1. Locust swarms could consume the food reserves of ______.
A. a whole village
B. a continent
C. the world
D. an entire country
2. What is a swarm of locusts NOT described in Paragraph 5?
A. A storm.
B. A cloud.
C. A tornado.
D. A drought.
3. The swarm of 1875 passed through the areas now known as ______.
A. Oklahoma, California, Kansas
B. Texas, South Dakota, Nebraska
C. Colorado, Washington, Oklahoma
D. Kansas, North Dakota, South Carolina
4. In Paragraph 10, which of the following does the writer imply about how the locusts affected America in the 1800s?
A. They infected many people with a deadly disease.
B. They caused economic and social damage.
C. They wiped out all American insects.
D. They warned farmers of tornadoes.
5. The main reason Lockwood journeys to the glaciers is because he has a hypothesis that ______.
A. locusts prefer the cold temperatures adjacent to glaciers
B. a swarm may still be living there
C. some locusts might be buried in the ice
D. the insects there have similar DNA to locusts
6. Which of these questions CANNOT be answered with the information provided in Paragraph 22?
A. What tool does Lockwood use to break the ice?
B. In what kind of condition are the locust specimens?
C. Does he have a complete specimen?
D. With how many specimens does Lockwood return?
7. The word "inherent in Paragraph 27 is closest in meaning to ______.
A. naturally existing
B. worthwhile
C. distinguished
D. vulnerable
8. Lockwood will have to look at what was happening to the locust when it was at its weakest, not when it was flourishing.