polunina_ln_bobrovskaia_im_priroda_nauka_tekhnologii

the quality of the soil, and the condition of the water table beneath it—a task that often lies beyond the means of private farming. A major thrust of research today is to develop techniques to conserve land that is already under irrigation.

(Adapted from Microsoft Encarta, 2008.)

1. Read the text and decide whether the following statements are TRUE, FALSE or there is NO such INFORMATION in the text.

1.Efficient use of available surface and groundwater supplies is becoming crucial at the moment.

2.Irrigation can increase a soil's salt level to the point where crops are damaged or destroyed.

3.Give the answer to the following question. What crops is flood irrigation used for?

1.Flood irrigation is employed with row crops such as cotton and vegetables.

2.Flood irrigation is used especially for feed crops such as alfalfa.

3.Flood irrigation can be used for all types of crops.

4.Flood irrigation is used for close-grown crops such as rice.

4. What is the main idea of the text?

1.Irrigation is practiced in all parts of the world where rainfall does not provide enough ground moisture.

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2.As greater demands are now being made on limited water resources, efficient use of available surface and groundwater supplies is becoming crucial.

3.A major thrust of research today is to develop techniques to conserve land that is already under irrigation.

4.Irrigation has greatly expanded the amount of arable land and the production of food throughout the world.

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UNIT 4

ECOLOGY

WARMING UP

1.Using your own words, try to explain the term ecology? What are the main aspects of ecology?

2.Explain the term ecosystem. Give examples of ecosystems.

3.Humans have disrupted ecosystems almost everywhere they have established themselves, at least in industrialized countries. Do you believe that humans could also improve an ecosystem?

4.What are the most serious environmental problems? How can these environmental problems be remedied?

READING

Although scientists over the past several decades have been pointing with alarm to the effects on our environment of human carelessness, it was not until the 1980s that topics such as the effects of acid rain on forests and lakes, the ‘greenhouse effect’, contamination of groundwater by nitrates and pesticides, reduction of ozone shield, major global climatic changes, and loss of tropical rain forests gained widespread publicity. These environmental problems fall within ecology, the broad discipline of biology that deals not only with plant and animal relationships but also with the scientific study of relationships of organisms to one another and to their environment.

The word ecology was first proposed by the German biologist Ernst Haeckel in 1869, and ecology was recognized as a field of biological investigation at the beginning of the 20th century. Its origins date back to early civilizations when humans first learned to modify their environment through the use of tools and fire. Since the 1960s, ecology has become a household word, too often used incorrectly as a synonym for environmental condition.

In the past two decades, concern about the effects of pollution on lands, waters, and peoples has been widely reported in the media and in

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scientific journals. During this time, attempts to rectify or arrest environmental damage have resulted in the requirement that various construction projects file environmental impact reports before proceeding. These reports provide information that helps different agencies evaluate the possible effects a proposed project may have on the flora, fauna, and physical environment and to determine what mitigations may be necessary before the project can or should be approved.

In feeding, clothing, and housing ourselves, we humans have had a major impact on our environment. We have cleared natural vegetation from vast areas of land and drained wetlands. We have dumped wastes and other pollutants into rivers, oceans, lakes, and added pollutants to the atmosphere, and we have killed pests and plant disease organisms with poisonous substances. These poisonous substances have also killed natural predators and other useful organisms, and in general have thoroughly disrupted the delicately balanced ecosystems that existed before humans began their depredations.

The greenhouse effect refers to a global rise in temperature due to the accumulation in the atmosphere of gases that permit radiation from the sun to reach the earth’s surface, but prevent the heat from escaping back into the space. Carbon dioxide and methane, the two most common gases involved in the greenhouse effect, have been part of our atmosphere for millions of years, but others, such as chlorofluorocarbons, are recently produced by products of the manufacture of refrigerants, plastics, and aerosol cans.

Acid rain occurs after the burning of fossil fuels releases sulphur and nitrogen compounds into the atmosphere. The acid rain, in turn, affects or even kills many living organisms on which it falls. It also affects nonliving materials. In 1989, Dr. Merle Robertson, an authority on pre-Columbian art, reported that the natural weathering of ancient Mayan ruins in southern Mexico has been accelerated by acid rain over the past decade or two.

Methane gas and chlorofluorocarbons, which are inert chemicals used for refrigeration and other industrial purposes, are broken down into active compounds by sunlight at high altitudes. The breakdown products destroy ozone, a form of oxygen that in the stratosphere provides a natural shield for living organisms against intense ultraviolet

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radiation. Increased ultraviolet radiation increases skin cancers. The accelerating weakening of the ozone shield has been recognized as a serious global problem by both the United States and the European Economic Community.

Chlorofluorocarbons are not the only force actively destroying the protective ozone layer. Halons, which are commonly found in electronic equipment, such as computer protection systems, and in portable fire extinguishers, are reported to be as much as 3 to 10 times more destructive of ozone than chlorofluorocarbons.

Human populations have increased dramatically in the past few centuries, and the disruption of ecosystems by the activities directly or indirectly associated with the feeding, clothing, and housing of billions of people threatens the survival of not only humans but many other living organisms as well.

(Adapted from Stern, K.R. Introductory Plant Biology)

Expand your vocabulary

to disrupt – разрушать contamination – загрязнение concern – беспокойство, интерес requirement – требование

to file – представлять, подавать (документ) mitigation – смягчение, уменьшение

to dump – сбрасывать pest – паразит

POST-READING ACTIVITY

1. Discuss the following questions.

1.What does ecology deal with?

2.What attempts have been made to rectify or arrest environmental damage?

3.What are the main environmental problems caused by the activities directly or indirectly associated with the feeding, clothing, and housing of billions of people?

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4.What does the greenhouse effect refer to?

5.What is the main function of the ozone layer? What destroys the ozone shield?

2. Here are some words in phonetics. Write the words.

3. Match the words with their meanings.

4. Find the word closest to the meaning of the italicized word from the reading.

1. In the past two decades, concern about the effects of pollution on lands, waters, and peoples has been widely reported in the media and in scientific journals.

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2. During this time, attempts to rectify or arrest environmental damage have resulted in the requirement that various construction projects file environmental impact reports before proceeding.

3. In feeding, clothing, and housing ourselves, we humans have had a major impact on our environment.

4. We have dumped wastes and other pollutants into rivers, oceans, lakes, and added pollutants to the atmosphere, and we have killed pests and plant disease organisms with poisonous substances.

5. Chlorofluorocarbons are not the only force actively destroying the protective ozone layer.

5. The following paragraph from the text is written in the present tense. Change it to the past tense by underlining the verbs and writing the past tense verb above the verb that is changed. As an example, the first one has been marked for you.

were

Methane gas and chlorofluorocarbons, which are inert chemicals used for refrigeration and other industrial purposes, are broken down into active compounds by sunlight at high altitudes. The breakdown products destroy ozone, a form of oxygen that in the stratosphere provides a natural shield for living organisms against intense ultraviolet radiation. Increased ultraviolet radiation increases skin cancers. The accelerating weakening of the ozone shield has been recognized as a serious global problem by both the United States and the European

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Economic Community.

6. Put questions to the words or word expressions in the bold type.

1.The word ecology was first proposed by the German biologist Ernst

Haeckel in 1869, and ecology was recognized as a field of biological investigation at the beginning of the 20th century.

2.We have cleared natural vegetation from vast areas of land and drained wetlands.

3.The greenhouse effect refers to a global rise in temperature due to the accumulation in the atmosphere of gases that permit radiation from the sun to reach the earth’s surface, but prevent the heat from escaping back into the space.

4.The acid rain, in turn, affects or even kills many living organisms on which it falls.

5.Increased ultraviolet radiation increases skin cancers.

LANGUAGE IN USE

7. Read the text and write out all the numerals written in numbers according to the example. Example: 20 - twenty

It has been estimated that the total human population of the world was less than 20 million in 6000 B.C. During the next 7,750 years it rose to 500 million; by 1850 it had doubled to 1 billion, and 70 years later it had doubled again to 2 billion. The 4.48 billion mark was reached in 1980 and within 5 years it had grown to 4.89 billion, and continues to increase exponentially. Estimates for 1990 and 2000 are 5.32 billion and 6.25 billion, respectively. The earth remains constant in size, but humans obviously have occupied a great deal more of it over the past few centuries or at least have greatly increased in density of population.

(Adapted from Stern, K.R. Introductory Plant Biology)

8. Arrange the parts of the text in logical order so that the text was complete.

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Human Impact on Biodiversity

(1)But the problem is not sheer numbers of people alone. The unequal distribution and consumption of resources and other forms of wealth on the planet must also be considered. According to some estimates, the average middle-class American consumes 30 times more than a person living in a developing nation consumes. Thus the impact of the 270 million American people must be multiplied by 30 to derive an accurate comparative estimate of the impact such industrialized nations have on the world’s ecosystems.

(2)The underlying cause of biodiversity loss is the explosion in human population, now at 6 billion, but expected to double again by the year 2050. The human population already consumes nearly half of all the food, crops, medicines, and other useful items produced by the Earth’s organisms, and more than 1 billion people on Earth lack adequate supplies of fresh water.

(3)The conversion of forests, grasslands, and wetlands for agricultural purposes, coupled with the multiplication and growth of urban centers and the building of dams and canals, highways, and railways, has physically altered ecosystems to the point that extinction of species has reached its current alarming pace.

(4)The greatest threat to global biodiversity is the human destruction of natural habitats. Since the invention of agriculture about 10,000 years ago, the human population has increased from approximately 5 million to a full 6 billion people. During that time, but especially in the past several centuries, humans have radically transformed the face of planet Earth.

(5)In addition, overexploitation of the world’s natural resources has greatly outstripped the rate at which these systems can recover. For example, 12 of the 13 largest oceanic fisheries are severely depleted. Modern fishing techniques, such as using huge fishing nets and bottom vacuuming techniques, remove everything in their paths – including tons of fish and invertebrates of no commercial use. These victims, as

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well as porpoises and seals that are also hauled in as accidental catches, are permanently removed from their populations, significantly altering the ecosystems in which they live.

(6)For example, the brown tree snake was introduced to the island of Guam, probably as a stowaway on visiting military cargo ships after World War II (1939-1945). The snake devastated the native bird population, driving over half a dozen native species of birds to extinction – simply because the native birds had not been exposed to this type of predator and did not recognize the danger posed by these snakes.

(7)As human populations have grown, people have spread out to the four corners of the Earth. In the process, whether on purpose or by accident, they have introduced nonnative species that have created ecological nightmares, disrupting local ecosystems and, in many cases, directly driving native species extinct.

(From Microsoft Encarta, 2008)

SPEAKING

9. Do you agree with the following? Give reasons for your answer. Do you think that special measures are required to protect threatened or endangered species that play key roles in the ecosystem?

Many organizations and government agencies have adopted a new approach to managing natural resources – naturally occurring materials that have economic or cultural value, such as timber and water – in order to prevent their catastrophic depletion. This strategy, known as ecosystem management, treats resources as interdependent ecosystems rather than simply commodities to be extracted.

10. What do you think about genetic engineering? What effects can it have on the environment? Discuss the advantages and disadvantages of it. Give reasons and specific examples to support your answer.

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