Английский язык = English. Учебное пособие

Lesson 5

SPECIES, POPULATIONS, COMMUNITIES,

ECOSYSTEMS

PART I

I. Read these international words and try to guess their meaning.

Organism, dynamic, population, ecosystem, morphologically, physiologically, situation, individual, identical, structure, regulation, genetic.

II.Enlarge your active vocabulary.

interbreeding [ˌ nt br :d ŋ] – межпородное скрещивание fertile [ f : ] – всхожий (о семенах); плодоносящий appropriate [ pr pr t] – соответствующий

acquisition [ˌækw z ( )n] – приобретение diversity [da v :s t ] – разнообразие, различие nutrient [ nju:tr nt] – питательное вещество

III. The biosphere (all living organisms of the Earth) is considered to be one of the four great realms, or spheres, of the Earth (together with the atmosphere, lithosphere and hydrosphere). Read the text to find out how life on the Earth is organized.

Organization of Life

Scientists have recognized that life can be organized into several different levels of function and complexity. These functional levels are: species, populations, communities and ecosystems.

Species are different kinds of organisms found on the Earth. A more exact definition of species is a group of interbreeding organisms that do not ordinarily breed with members of other groups. If a species interbreeds freely with other species, it would no longer be a distinctive kind of organism. This definition works well with animals. However, in some plant species fertile crossings can take place among morphologically and physiologically different kinds of vegetation. In this situation, the definition of species given here is not appropriate.

A population comprises all the individuals of a given species in a specific area or region at a certain time. Its significance is more than that of a number

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of individuals because not all individuals are identical. Populations contain genetic variation within themselves and between other populations. Even fundamental genetic characteristics such as hair colour or size may differ slightly from individual to individual. More importantly, not all members of the population are equal in their ability to survive and reproduce.

The term ‘community’ refers to all the populations in a specific area or region at a certain time. Its structure involves many types of interactions among species. Some of these involve the acquisition and use of food, space, or other environmental resources. Others involve nutrient cycling through all members of the community and mutual regulation of population sizes. In all of these cases, the structured interactions of populations lead to situations in which individuals are thrown into life or death struggles.

In general, ecologists believe that a community that has a high diversity is more complex and stable than a community that has a low diversity. This theory is founded on the observation that the food webs of communities of high diversity are more interconnected. Greater interconnectivity causes these systems to be more resilient to disturbance. If a species is removed, those species that relied on it for food have the option to switch to many other species that occupy a similar role in that ecosystem. In a low diversity ecosystem, possible substitutes for food may be non-existent or limited in abundance.

Ecosystems are dynamic entities composed of the biological community and the abiotic environment. An ecosystem’s abiotic and biotic composition and structure is determined by the state of a number of interrelated environmental factors. Changes in any of these factors (for example, nutrient availability, temperature, light intensity, grazing intensity, and species population density) will result in dynamic changes in the nature of these systems. For example, a fire in the temperate deciduous forest completely changes the structure of that system. There are no longer any large trees, most of the mosses, herbs, and shrubs that occupy the forest floor are gone, and the nutrients that were stored in the biomass are quickly released into the soil, atmosphere and hydrologic system. After a short time of recovery, the community that was once large mature trees now becomes a community of grasses, herbaceous species, and tree seedlings.

IV. Give the Russian equivalents of the following English words and phrases.

To be organized into several different levels of function and complexity, a group of interbreeding organisms, to breed with, fertile crossing, genetic variation, the ability to survive and reproduce, a community, interaction among species, nutrient cycling, mutual regulation of population sizes, a high/low

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diversity, the food webs of communities, to be more resilient to disturbance, the abiotic environment.

V. Match the words with their definitions.

1) the total number of species present;

2) a partial or complete alteration of a community or an ecosystem by a biotic or abiotic factor;

3) the individuals of a given species that occupy the same locality and form the interbreeding group in that location;

4) a model describing the organisms found in a food chain. It describes the complex patterns of energy flow in an ecosystem by modeling who consumes who;

5) a non-living thing. This word usually refers to the physical and chemical components of an organism’s environment. It is also called inorganic;

6) a community of species together with the surrounding environment that function together as a coherent unit to maintain a flow of energy and to acquire, store, and recycle nutrients;

7) a group of populations of different species occupying a given place at a given time that are viewed as interdependent.

VI. Answer the following questions.

1.What levels of life organization are recognized by scientists?

2.What is a species?

3.In what cases does the definition of species work no longer?

4.What is a population?

5.What does the term ‘community’ refer to?

6.What does its structure involve?

7.What community is considered to be more complex and stable?

8.What is an ecosystem?

9.What are some of the major components of ecosystems? How are these components related to each other?

VII. Complete the following sentences with the information from the text.

1. This text deals with the problem of … . 2. Scientists have recognized that organisms can be organized according to … . 3. The functional level

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known as species refers to … . 4. This definition does not work when … . 5. All of the different organisms of a single species that occupy … represent … . 6. Genetic variability found in a population of species is called … . 7. A community is defined as … . 8. The structure of a community involves many types of … which lead to … . 9. A community that has … is more stable and complex than a community that has … . 10. The most complex functional level of life organization is … . 11. It consists of … . 12. Changes in any of environmental factors can cause … .

VIII. Read the following text. Make an annotation of it in written form. Compare your annotation with your partner’s. Present it to the group. Use the given phrases:

distribution – распределение

to survive – продолжать существовать predator – хищник

The geographic distributions of plant and animal species are never fixed over time. Geographic ranges of organisms shift, expand, and contract. These changes are the result of two contrasting processes: 1) colonization and establishment and 2) localized extinction. Colonization and establishment take place when populations expand into new areas. A number of processes can initiate this process including disturbance and abiotic environmental change. Localized extinction results in the elimination of populations from their former range. It can be caused by biotic interactions or, once again, abiotic environmental change.

Most species appear to be limited in their geographic range by abiotic factors, such as temperature, moisture availability, and soil nutrients. No species is adapted to survive under all conditions found on the Earth. All species have specific limits of tolerance to physical factors that directly effect their survival or reproductive success. The portion of the abiotic factor’s range of variation which a species can survive and function in is commonly defined as the tolerance range. The level within the tolerance range at which a species or population can function most efficiently is termed the optimum.

For a species to maintain its population, its individuals must survive and reproduce. Certain combinations of environmental conditions are necessary for individuals of each species to tolerate the physical environment, obtain energy and nutrients, and avoid predators. The total requirements of a spe-

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cies for all resources and physical conditions determine where it can live and how abundant it can be at any place within its range. These requirements are termed abstractly the ecological niche.

IX. Find information about any unique species of animals or plants and prepare a report on the subject.

X. Plan a television documentary programme on organization of life. Make a list of topics you would like the programme to cover. Write a script for the announcer’s opening and closing statements.

PART II

I.Read these international words and try to guess their meaning.

Tanker, gallon, erosion, filter, dolphin, chemical, toxic, pesticide.

II.Enlarge your active vocabulary.

to dredge [dred ] – производить дноуглубительные работы newsworthy [ nju:zw :ð ] – достойный освещения в печати

rig – буровая установка to foul [fa l] – загрязнять to hatch [hæt ] – выводить

to endanger [ n de nd ] – подвергать опасности noxious [ n k s] – вредный, ядовитый

III. For many years people have been modifying and polluting coastal and wetland ecosystems. Read the text and pick out the facts which prove that U.S. coastlines and wetlands are under tremendous pressure from conflicting uses and rapidly rising land and water values.

Human Alteration of Coastal and Wetland Ecosystems

In the United States, the Atlantic, Gulf, Pacific, and Great Lakes coastlines are all under tremendous pressure from conflicting uses and rapidly rising land values. Coastal and wetland ecosystems worldwide have become extensively modified and polluted. Especially near large cities, coastal and wetland modification and pollution have taken their greatest toll. Dredging for harbors and expanding port facilities and filling of wetlands for airports, marinas, dumps, and industrial sites have completely changed the world’s urban shorelines. Conflicting uses for residential development, industry,

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sewage treatment, energy production, agriculture, fishing, recreation, and environmental protection have intensified the demand and driven the land values upward.

Probably the most visible and newsworthy problem has been from oil pollution, especially from tankers, but also from offshore oil rigs. Oil spills know no boundaries and are a worldwide problem with recent major spills in the Persian Gulf, the North Sea, the English Channel, the Gulf of Mexico, the Mississippi, Chesapeake Bay, Puget Sound, Alaska and even in remote Antarctica. Yet even with the numerous spills, the demand for oil will keep tankers crossing the seas into the foreseeable future and will increase pressure to drill off-shore in productive marine areas such as off Alaska, California, Louisiana, New England, Newfoundland, and Antarctica.

In 1989 the Exxon Valdez ran around in Alaska’s Prince William Sound, spilling millions of gallons of oil and fouling hundreds of miles of coastline in one of the world’s richest marine wildlife areas. It was the largest oil spill in U.S. history. The spill harmed Alaskan commercial fisheries and killed thousands of seabirds and marine mammals. Uncounted millions of smaller creatures were also killed by the oil slick as it washed onto the pristine, rocky shoreline. Though cleanup efforts are attempted, after a major oil spill there really is no possibility of a clean coast, and only many years of natural healing can erase the damage caused by a minute of human folly and carelessness.

Wetlands, once considered useless swamp by many, are now regarded as some of the most complex and important ecosystems in the world. Two thirds of all the fish caught in U.S. waters are hatched in wetland areas. The wetlands also serve as a site for millions of native and migratory birds and the home for over one third of the nation’s endangered species.

In recent years they have discovered that these wetlands offer a stabilizing effect on the shorelines of seas, lakes, and rivers. Their loss drastically increases the erosion rates around these water bodies. They have also discovered that wetlands have a great capacity to filter and purify water. The saturated grounds beneath the wetland vegetation naturally break down pollutants into harmless substances. Over 50 municipalities nationwide have developed systems where wetlands are now used to help treat sewage.

Through recent media attention to spectacular events such as the Exxon Valderz oil spill, the dolphins dying off the U.S. East Coast, outbreaks of contaminated shellfish sickness, or syringes and bloody hospital wastes washing up on beaches, many Americans are becoming aware of the danger that their carelessness causes. Yet it is probably the unseen pollutants lurking below the surface that are the most dangerous to the environment. According to the Environmental Protection Agency, the United States spews 32 million gallons of sewage and chemicals into the oceans and seas everyday. Half

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the pollutants come from industry, which pours noxious and toxic materials into the water. The other half comes from sewage plants, urban runoff, and agricultural pesticides and fertilizers.

Many wetland ecosystems could be cleaned up and much of the coastal ocean could clean itself if pollution and environmental destruction were halted. It will cost billions of dollars, however, and require improved sewage treatment, more severe pollution penalties, and protection for diminishing wetlands. As these are some of the most productive ecosystems on the planet, immediate action is imperative.

IV. Give the Russian equivalents of the following English words and phrases.

To be under tremendous pressure, worldwide, to become extensively modified, residential development, to drive the land values upward, remote Antarctica, the demand for, productive marine areas, a marine mammal, to serve as a site, to increase drastically, to purify, contaminated shellfish sickness, improved sewage treatment, severe pollution penalties, imperative.

V. Match the words from column A with the suitable words from column B to make word combinations.

VI. Fill in the blanks with prepositions where necessary.

1.In the United States a lot of areas are … tremendous pressure from conflicting uses and rapidly rising land values.

2.Dredging … harbors has completely changed the world’s urban shorelines.

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3.The most visible and newsworthy problem has been … oil rigs.

4.The wetlands serve as a site … millions … native and migratory birds.

5.The saturated grounds beneath the wetland vegetation naturally break

…pollutants … harmless substances.

6.Some countries spew millions of gallons of sewage and chemicals … the oceans and seas everyday.

VII. Answer the following questions.

1.What areas in the U.S. are under tremendous pressure from conflicting uses and rapidly rising land values?

2.Where have coastal and wetland modification and pollution taken their greatest toll?

3.What has intensified the demand and driven the land values upward?

4.What problem has been the most visible and newsworthy one?

5.What was the largest oil spill in U.S. history? What was the damage

of it?

6.What is the use of wetland ecosystems?

7.What does the loss of wetland ecosystems cause?

8.Where do the pollutants in the United States come from?

VIII. Say whether the following statements are true or false. Correct the false statements to make them true. Use the introductory phrases:

1.Coastal and wetland modification and pollution have taken their greatest toll near small towns and villages.

2.The most visible and newsworthy problem has been from oil pollution, especially from tankers, but also from off-shore oil rigs.

3.The demand for oil will keep tankers crossing the seas into the foreseeable future and will increase pressure to drill off-shore in productive marine areas.

4.The spill of millions of gallons of oil in the Gulf of Mexico was the largest oil spill in U.S. history.

5.Millions of smaller creatures were killed by the oil slick in Alaska’s Prince William Sound.

6.Two thirds of all the fish caught in U.K. waters are hatched in wetland

areas.

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Lesson 6

THE EARTH’S BIODIVERSITY

PART I

I. Read these international words and try to guess their meaning.

Mollusc, biome, the Industrial Revolution, amphibian, reptile, catastrophe, meteor, anatomical.

II.Enlarge your active vocabulary.

biodiversity [ˌba da v :s t ] – биологическое разнообразие invertebrate [ n v :t br t] – беспозвоночное (животное) worm [w :m] – червь

urchin [ :t n] – морской ёж

crustacea [kr s te j ] – pl. ракообразные

to eliminate [ l m ne t] – уничтожать, ликвидировать assessment [ sesm nt] – оценка

III. Scientists believe that life appeared on the Earth about 3.5 billion years ago. At first, life was biologically simple and consisted of unicellular organisms. However, as time went on life became more complex and diversified because of evolution. Read the text and say what factors influence the biodiversity of the Earth.

Species Diversity and Biodiversity

Biologists are not completely sure how many different species live on the Earth. Estimates of how many species exist on the Earth range from 2 million to about 100 million. To date, about 2.1 million species have been classified, primarily in the habitats of the middle latitudes. Most of the unclassified species on this planet are invertebrates. This group of organisms includes insects, spiders, mollusks, sponges, flatworms, starfish, urchins, earthworms, and crustacea. These species are often difficult to find and identify because of their small size and the fact that they live in habitats that are difficult to explore. In the tropical rain forest, cataloging of species has been quite limited because of this later reason. Scientists estimate that this single biome may contain 50 to 90% of the Earth’s biodiversity.

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