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Conservation and Environmental Movements




Since the 19th century, environmentalists and other conservationists have used ecology and other sciences (e.g., climatology) to support their advocacy position. Environmentalist views are often controversial for political or economic reasons. As a result, some scientific work in ecology directly influences policy and political debate; these in turn often direct ecological research.

Ecology and Global Policy

Ecology became a central part of the World’s politics as early as 1971, UNESCO launched a research program called Man and Biosphere, with the objective of increasing knowledge about the mutual relationship between humans and nature. A few years later it defined the concept of Biosphere Reserve.

In 1972, the United Nations held the first international conference on the human environment in Stockholm, prepared by Rene Dubos and other experts. This conference was the origin of the phrase «Think Globally, Act Locally». The next major events in ecology were the development of the concept of biosphere and the appearance of terms «biological diversity» — or now more commonly biodiversity - in the 1980s. These terms were developed during the Earth Summit in Rio de Janeiro in 1992, where the concept of the biosphere was recognized by the major international organizations, and risks associated with reductions in biodiversity were publicly acknowledged.

Then, in 1997, the dangers the biosphere was facing were recognized from an international point of view at the conference leading to the Kyoto Protocol. In particular, this conference highlighted the increasing dangers of the greenhouse effect - related to the increasing concentration of greenhouse gases in the atmosphere, leading to global changes in climate. In Kyoto, most of the world’s nations recognized the importance of looking at ecology from a global point of view, on a worldwide scale, and to take into account the impact of humans on the Earth’s environment.

Exercises

A. Comprehension

I. Answer these questions.

1. When was human impact on the environment first recognized?

2. How do humans modify their environment?

3. What was the result of the human ecology development?

4. When did the term «biodiversity» appear and was recognized?

5. What increasing dangers for the biosphere were acknowledged in 1997?

II. Speak on the origin of the phrase «Think Globally, Act Locally». Expand it, showing your opinion.

III. Make a summary of the text.

B. Vocabulary

IV. Give Russian equivalents of the following words and word combinations: to

to argue Mining to reject
logging Recent to take into account
equilibrium perception to reject
controversial ensemble advocacy
on a worldwide scale objective mutual relationship

 

V. Find synonyms of these expressions among the words and word combinations from the previous exercise.

1) to claim, say, make a case, contend;

2) contentious, divisive, hot;

3) latest, up to date, contemporary, current, fresh;

4) group, company, collection;

5) purpose, aim, goal, intention;

6) awareness, observation, acuity;

7) to decline, refuse, eliminate, disallow, deny;

8) cutting down, deforestation;

9) minerals removal, taking out;

10) balance, stability;

11) support, encouragement, promotion;

12) take into consideration, bear in mind, consider.

VI. Find in the text English equivalents of the following words and expressions. Translate the sentences which contain them.

1) вырубка леса; 2) побочный эффект: 3) утверждать, приводить аргументы; 4) отвергать; 5) баланс, равновесие; 6) группа, множество;7) осознание, понимание; 8) противоречивый; 9) цель; 10) в мировом масштабе; 11) принимать во внимание, в расчет.


Unit 4.

Fundamental Principles of Ecology

Biosphere

For modem ecologists, ecology can be studied at several levels: population level (individuals of the same species), biocoenosis level (or community of species), ecosystem level, and biosphere level.

The outer layer of the planet Earth can be divided into several compartments: the hydrosphere (or sphere of water), the lithosphere (or sphere of soils and rocks), and the atmosphere (or sphere of the air). The biosphere (or sphere of life), sometimes described as «the fourth envelope», is all living matter on the planet or that portion of the planet occupied by life. It reaches well into the other three spheres, although there are no permanent inhabitants of the atmosphere. Relative to the volume of the Earth, the biosphere is only the very thin surface layer which extends from 11,000 meters below sea level to 15,000 meters above.

It is thought that life first developed in the hydrosphere, at shallow depths, in photic zone. Although recently a competing theory has emerged, that life originated around hydrothermal vents in the deeper ocean. Multicellular organisms then appeared and colonized benthic zones. Photosynthetic organisms gradually produced the chemically unstable oxygen-rich atmosphere that characterizes our planet. Terrestrial life developed later, after the ozone layer protecting living beings from UV rays had been formed. Diversification of terrestrial species is thought to be increased by the continents drifting apart, pr alternately, colliding. Biodiversity is expressed at the ecological level (ecosystem), population level (intraspecific diversity), species level (specific diversity), and genetic level. Recently technology has allowed the discovery of the deep ocean vent communities. This remarkable ecological system is not dependent on sunlight but bacteria, utilizing the chemistry of the hot volcanic vents, are at the base of its food chain.

 

The biosphere contains great quantities of elements such as carbon, nitro­gen and oxygen. Other elements, such as phosphorus, calcium, and potassium, are also essential to life, yet are present in smaller amounts. At the ecosystem and biosphere levels, there is a continual recycling of all these elements, which alternate between the mineral and organic states.

While there is a slight input of geothermal energy, the bulk of the functioning of the ecosystem is based on the input of solar energy. Plants and photosynthetic microorganisms convert light into chemical energy by the process of photosynthesis, which creates glucose (a simple; sugar) and releases free oxygen. Glucose thus becomes the secondary energy source which drives the ecosystem. Some of this glucose is used directly by other organisms for energy. Other sugar molecules can be converted to other molecules such as amino acids. Plants use some of this sugar, concentrated in nectar to entice pollinators to aid them in reproduction.

Cellular respiration is the process by which organisms (like mammals) break the glucose back down into its constituents, water and carbon dioxide, thus regainnig the stored energy the sun originally gave to the plants. The pro­portion of photosynthetic activity of plants and other photosynthesizers to the Aspiration of other organisms determines the specific composition of the Earth’s atmosphere, particularly its oxygen level. Global air currents mix the atmosphere and maintain nearly the same balance of elements in areas of intense biological activity and areas of slight biological activity..

Water is also exchanged between the hydrosphere, lithosphere, atmosphere and biosphere in regular cycles. The oceans are large tanks, which store water, ensure thermal and climatic stability, as well as the transport of chemical elements, thanks to large oceanic currents.

For i better Understanding of how the biosphere works, and various dysfunctions related to human activity, American scientists simulated the biosphere in ai small-scale model, called Biosphere II.

 

EXERCISES

A. Comprehension

I. Answer these questions.

 

1. Why is the biosphere described sometimes as «the fourth envelope»?

2. Where did life first develop? How?

3. What elements does the biosphere contain?

4. How is light converted into glucose and other sugar molecules?

5. What determines the specific composition of the Earth’s atmosphere?

6. How important аде the oceans for water cycling?

 

II. Decide whether these statements are true or false (T/F).

1. The biosphere is sphere of soils and rocks.

2. The ozone layer protects living beings from UV rays.

 

3. The deep ocean vent communities need sunlight for utilizing the chemistry of the hot volcanic vents.

4. At the ecosystem and biosphere levels, there is a continual recycling of carbon, nitrogen, oxygen and other elements, such as phosphorus, cal­cium, and potassium.

5. The process of photosynthesis releases carbon.

6. Glucose and other sugar molecules are concentrated in nectar and entice pollinators to aid plants in reproduction.

7. Water and carbon dioxide are the two constituents which cause the proc­ess of cellular respiration.

8. Water cycles between the hydrosphere, lithosphere, atmosphere and bio­sphere.

 

B.Vocabulary

III. Transcribe the following words.

hydrosphere...... …………………………...... hydrothermal……………………..

multicellular........................................... nitrogen…………………………..

calcium…………………………………....potassium…………………….. …..

photosynthesis.. …………………………molecule………………………….

amino acids……………………………….dioxide……………………………

 

VI. Give Russian equivalents of the following expressions:

outer layer; living matter; permanent inhabitants; to extend; photic zone; shallow depths; benthic zone; terrestrial life; to drift apart; vent; amino acids; solar energy; to alternate; cellular respiration; to regain; global air currents; to maintain; mammal; intense biological activity; carbon dioxide; to release; secondary energy source; to entice; phosphorus; input; to reach well into.

 

V. Translate the given words and word combinations into English:

глобальное потепление живая материя

физические свойства приманивать

почвоведение углекислый газ

освещение лучами солнца (инсоляция) глюкоза

трутень калий

покорять природу воздушный поток

распределение организмов относительно размера земли

последствия изменений выделять

быть обеспокоенным чем-либо многоклеточный

нуклеиновая кислота обеспечивать стабильность

VI. Complete the text with the following words and word combina­tions.

 

 

oxygen, biosphere, energy, free oxygen, environment, carbon, hydrosphere, water, solar energy, plants, lithosphere, photosynthesis, nitrogen, atmosphere

The first step to an understanding the interrelationship of living organisms

and their nonliving ……… is to begin with the sun. From it comes most of the

.......... on earth. But, it is largely unavailable to animals directly. It must be

transmitted to them by green vegetation through a process known as ……...

In this process the ………. is transferred through a substance in the vegetation

called chlorophyll (from Greek, chloros, green, and phyllos, leaf) in the pres­ence of water to become ………. and food sugar. Now, animals can receive their

energy by eating …….. or other animals (who have eaten plants at some stage).

As plants and animals decay, with the help of bacteria and fungi, they release chemicals in the earth, helping to feed plants.

This circulation makes the earth’s basic substances - ………. - and

others move between the earth’s main stratums: air (the …….), water

(the……..) soil and rocks (the...........) and living organisms (the……..).

 

C.Reading and Discussion

Retell the following text in English. Mention the points of differ­ence between the English and Russian texts in the presentation and interpretation of facts concerning the biosphere.

Понятие «биосфера»

Содержание понятия «биосфера» не всегда было однозначным. Первоначально биосферами называли гипотетические глобулы, якобы составляющие живую основу всех организмов. Такое понимание про­держалось во Франции до середины XVIII века.

Существенно иное представление о биосфере сформулировал в 1875 г. австрийский геолог Э. Зюсс. В монографии «Происхождение Альп» он говорит о «самостоятельной биосфере» как об особой оболочке Земли, образованной живыми организмами. В заключительной главе большого трехтомного труда «Лик Земли» (1909) этот автор пишет, что понятие «биосфера» возникло как следствие идей Ж. Ламарка и Ч. Дарвина о единстве органического мира.

С работ Зюсса датируется начало биологического представления

о биосфере, как о совокупности организмов, населяющих Землю, как о живой оболочке планеты. Такого взгляда придерживались многие рус­ские географы, например Н.М.Сибирцев (1899), Д.Н.Анучин (1902), П.И.Броунов (1910), А.А.Григорьев (1948), английский исследователь и философ Дж. Бернал (1969). Французские учёные Э.Леруа (1927) и П.Тейяр де Шарден (1965, 1969) также взяли за основу определение Зюсса, однако трактуют его в идеалистическом плане. Согласно Тейяру, биосфера — живой пласт планеты — одна из стадий воплощения Бога.

 

Представление Зюсса о биосфере так об особой оболочке земли ис­пользовал и В.И.Вернадский (1926), вложив в него, однако, сущест­венно иное, биогеохимическое, содержание. Биосфера, по Вернадско­му, — область распространения жизни, включающая наряду с организ­мами и среду их обитания. Тейляр де Шарден в сборнике статей «Бу­дущее человека» (1969) выразил своё несогласие с подобной трактовкой, явно противоречащей его идеалистической концепции эволюции.

Разработка биогеохимического представления о биосфере была тес­но связана с практической деятельностью В. И. Вернадского в Комиссии Академии наук по изучению естественных производственных сил России (начало 1915 г.).

Зачатки этого представления можно обнаружить уже в высказыва­ниях ученых XVII и XVIII вв., в книге «Космос» А Гумбольдта и В.В.Докучаева.

В настоящее время оба понимания биосферы, по Зюссу и по Вер­надскому, существуют. Н.В. Тимофеев-Ресовский предлагает говорить о биосфере в узком и широком понимании. Представляется более це­лесообразным употреблять это понятие, вкладывая в него смысл, при­данный Вернадским, — область распространения жизни, используя для биосферы в «узком смысле» выражения: «совокупность организмов», «пленка жизни», «живой покров Земли», «биота», «биос».

Верхняя граница биосферы, по Вернадскому (1965), проходит на вы­соте 15 -20 км, охватывая всю тропосферу и нижнюю часть стратосферы: озон находится у полюсов в слое 8-30 км, в тропиках - 15-35 км. Снизу биосфера ограничена отложениями на дне океанов (до глубины свыше 10 км) и глубиной проникновения в недра Земли организмов и воды в жидком состоянии. Подстилающая литосфера, верхняя стратосфера, ионосфера и космическое пространство служат биосфере средой. Ос­новной энергетический источник, обеспечивающий функциониро­вание биосферы, — лучистая энергия Солнца.

Таким образом, биосфера — это особая термодинамическая открытая оболочка Земли, вещество, энергетика и организация которой и обуславливаются взаимодействием её биотического и абиотического ком­понентов. Она, следовательно, включает совокупность организмов и их остатки, а также части атмосферы, гидросферы и литосферы, насе­лённые организмами и изменяемые их деятельностью.

Важнейшей функцией биосферы является регулярное, возрастаю­щее во времени воссоздание живого вещества по численности, весу и количеству аккумулированной и удерживаемой энергии. Человек воспринимает эту функцию как биологическую продуктивность биосферы, её частей (океан, почвы, пресные воды) или её отдельных. Экосистем и биогеоценозов (дельты, луга, тайга, поля зерновых и т.д.).

 


hypothetical globule; underlying lithosphere; sediments (отложения); radiant energy

VIII. Read the text carefully, without a dictionary. While reading, pay special attention to the words that you don’t know: look carefully at the context and see if you can get the idea of what they mean. After reading answer the question: how is the biosphere connected with other components? Point out the information that was new to you.

The term «Biosphere» was coined by Russian scientist Vladimir Vernadsky in the 1929. The biosphere is the life zone of the Earth and includes all living organisms, including man, and all organic matter that has not yet decomposed. Life evolved on earth during its early history between 4,5 and 3,8 billion years ago and the biosphere readily distinguishes our planet from all others in the solar system. The chemical reactions of life (e.g., photosynthesis-respiration, carbonate precipitation, etc.) have also imparted a strong signal on the chemical composition of the atmosphere, transforming the atmosphere from reducing conditions to and oxidizing environment with free oxygen. The biosphere is structured into a hierarchy known as the food chain whereby all life is dependent upon the first tier (i.e. mainly the primary producers that are capable of photosynthesis). Energy and mass are transferred from one level of the food chain to the next with an efficiency of about 10 %. All organisms are intrinsically linked to their physical environment and the relationship between an organism and its environment is the study of ecology. T le biosphere can be divided into distinct ecosystems that represent the interactions between a group of organisms forming a trophic pyramid and the environment or habitat in which they live.

Links to other components:

Atmosphere: Life processes involve a vast number of chemical reactions some of which either extract or emit gases from and to the atmosphere. For example, photosynthesis consumes carbon dioxide and produces oxygen whereas respiration does the opposite. Other examples of biogenic gases in the atmosphere include methane, dimethylsulfide (DMS), nitrogen, nitrous oxide, ammonia, etc.).

Hydrosphere: Water is essential for all living organisms on the Earth and has played a key role in the evolution and sustenance of life on our planet. The biosphere as we know it would not exist without liquid water (for example, consider Mars). Water is also important for transport the soluble nutrients (phosphate and nitrate) that are needed for plant growth, and for transporting the waste products of life’s chemical reactions.

Geosphere: The geosphere and biosphere are intimately connected through soils, which consist of a mixture of air, mineral matter, organic matter, and water. In fact, one could consider soil as composed of all four spheres (atmosphere, geosphere, biosphere, and hydrosphere). Plant activity such as root growth and generation of organic acids are also important for the mechanical and chemical breakdown (weathering) of the geosphere.

Anthrosphere: Human population poses a threat to the biosphere by habitat destruction, especially by the destruction oftropical rainforests (deforestation). This process is driving thousands of species each year to extinction and reducing biological diversity

Summarize the text.

 

IX. Talking points.

 

1. The biosphere as one of the Earth’s compartments.

2. The biosphere functioning.

3. The origin of the word «biosphere» and its brief history.

 

 

Unit 3.

Biodiversity

Biodiversity is a word that describes the variety of living things. «Bio» (from a Greek world) refers to living and «diversity» refers to differences and variety. Living organisms express their diversity in hundreds of different ways — both external and visible and internal and invisible.

There are 3 kinds of biodiversity

♦ Variety of genes

Poodles, beagles, and rottweilers are all dogs — but they’re not the same because their genes are different. It’s the difference in our genes that makes us nil different.

♦ Variety among species

Scientists group living things into distinct kinds of species. For example, •logs, dragonflies, and daisies are all different species.

♦ Variety of ecosystems

Coral reefs, wetlands, and tropical rain forests are all ecosystems. Each one is different, with its own unique species living in it. Genes, species, and ecosystems working together make up our planet’s biodiversity.

 

There is genetic diversity within a species, which results in the differences between you and your brothers and sisters and cousins and grandparents even though we all members of the human race — the species Homo Sapiens. Ge­netic diversity means that an Ethiopian looks different from a Scandinavian or» Japanese person and that inherited diseases run in some families, but not in others. Genetic diversity is the reason why Siamese cats have different body shape and hair colouring from the black and white moggy next door.

There is evolutionary diversity, which has given rise to all the different species of animals and plants on this Earth and is genetic diversity on a wider scale. This is also known as species diversity.

Each species is adapted — and sometimes highly specialised — to survive in a particular environment or range of environments. Only the human species, through cultural and racial diversity and technology, seems to have adapted itself to survive in almost every environment on the Earth.

Ecologists call the role a species plays in its environment a «niche» — like an actor playing the villain, the hero or the comic, in a play. The role may be that of a plant colonizing bare ground, a caterpillar consuming that plant or a wasp preying on the caterpillar. Because there are so many possible niches in all the vast inhabitable areas of the Earth, millions of species have evolved to fill them. Hence the wonderful ecosystem diversity of the planet.

Adaptation by different species to widely separated, but similar types of environments and niches, has led to convergent evolution, where organisms have a similar life style and appearance but are not related. The diversity is there despite superficial similarities.

Lastly, there is cultural diversity, which people will argue is not part of biodiversity. But if you think of it as being the result of evolution and adaptation then it surely is. It applies mostly to us — Homo Sapiens — and is something learned from family, tribal and national groups. Cultural diversity helps the survival process by binding groups together and passing on traditions which help people live in their local environment.

In 1992 the world’s government leaders met at a convention in Rio de Janeiro, in Brazil — the country that holds the largest, but fast disappearing, rainforest. The purpose of the convention was to discuss the growing concern, amongst scientists of all nations, about the rapid extinction of the world’s non­human fauna and flora, the depletion of the world’s resources and the causes and effects of global warming. Various decisions were made, out of which arose the UK’s Local Agenda 21 and the Biodiversity Action Plan.

In July 1997, the World’s leaders met again, to look at where they had got in terms of reducing the so-called Greenhouse Gases which cause global warming. Not very far, it seems.

How can we study the biodiversity around us? One way is to keep a Nature Diary.

Many of the world’s different plants and animals are under severe threat of extinction. Many species are lost already.

A species is said to be extinct when it has not been seen for over 50 years. Dinosaurs became extinct 65 million years ago but, in the last 50 years, more animals and plants have become extinct, because of hunting and loss of habitat. Glo­bally, many hundreds of species will face extinction in a very few years without intensive conservation, education and environmental management and policy-making.

Exotic species are animal and plant species that find themselves outside their native habitat. Scientists have recorded 1,75 million species on our planet and estimate another 5 to 100 million unrecorded species! The educated guess stands at 12,5 million.

These species cause changes to the ecosystem and sometimes destroy other species native to that ecosystem. For example, zebra mussels came from Europe to the Great Lakes of North America in the ballast of ships. They spread like plague in the waterways of the continent, attaching themselves to existing mussels and killing them. Breeding quickly, they clog up hydro-electric generators, encrust the hulls of boats and erode pipes in water treatment plants.

Living organisms are made up of cells. Scientists have found a way to copy, Or clone, the information, or genes found in cells to make new plants and animals. But no one knows if it is totally safe to take genes from one species and add them another Well-known examples of genetic manipulation include Dolly the sheep — the first cloned mammal, and adding the genes of a toad or a spider to vegetables.

Exercises

A.Comprehension

I. Answer these questions.

1. What language does the word «biodiversity» come from?

2. How many type is of diversity do you know? Explain the difference be­tween them.

3. Can each species adapt itself to survive in almost all. environment on Earth? Prove

your statement.

4. What does the author compare an ecological niche with? Why?

5. Is cultural diversity a part of biodiversity?

 

6. What is being done to stop the rapid extinction of the world’s non-human fauna and flora?

7. How can you define an extinct species? Give examples.

8. What method of making new plants and animals have you learned from the text?

 

II. Define the term «exotic species» and its value for an ecosystem.

III. Place these sentences in the correct order by referring to the information in the text.

1. Evolutionary diversity has given rise to all the different species of animals and plants on Earth.

2. Because there are so many possible niches in all the vast inhabitable areas of the Earth, millions of species have evolved to fill them.

3. Living organisms express their diversity in hundreds of different ways — both external or visible and internal or invisible.

4.Many of the world’s different plants and animals are under severe threat of extinction.

5. Cultural diversity helps the survival process by binding groups together and passing on traditions which help people live in their local environment.

6. Genetic diversity within a species results in the differences between you and your brothers and sisters and cousins and grandparents even though we all members of the human race.

7. Living organisms are made up of cells.

8. Only the human species, through cultural and racial diversity and technology, seems to have adapted itself to survive in almost every environment on Earth.

 

A.Vocabulary

IV. Transcribe the following words.

species………………………………. Homo Sapiens………………………….

Ethiopian……………………………..Siamese…………………………………

caterpillar…………………………….wasp…………………………………….

niche…………………………………dinosaurs………………………………..

plague………………………………...fauna ……………………………………

 

V. Give Russian equivalents of the following expressions:

genetic diversity

caterpillar

biodiversity variety rainforest

inherited diseases hair colouring mussel

to consume to prey to reduce

rapid extinction to destroy

plague to estimate

cell toad

 

 

VI. Match these definitions with the words from Exercise 5.

1. to eat or drink;

2. a microscopic unit of living matter;

3. soft white substance that forms on teeth and that encourages the growth of harmful bacteria;

4. hot, wet forest in tropical areas;

5. quick dying out;

6. number or range of different things;

7. to hunt, to take;

8. rough-skinned, frog- like animal;

9. to calculate the value, cost;

10. to break to pieces, make useless, put an end to.

 

C. Reading and Discussion

VII. Retell the following text in English. Mention the points of •inference between the English and Russian texts in the presentation Wd interpretation of facts concerning biodiversity.

 

Кратко о биоразнообразии

Биоразнообразие — сокращенное от «биологическое разнообраз­ие» - означает разнообразие живых организмов во всех его проявлениях: от генов до биосферы. Вопросам изучения, использования и cохранения биоразнообразия стало уделяться большое внимание после подписания многими государствами Конвенции ООН о биологическом разнообразии в 1992 г. в Рио-де Жанейро.

Существует три основных типа биоразнообразия:

- генетическое разнообразие, отражающее внутривидовое разнообразие и обусловленное изменчивостью особей;

- видовое разнообразие, отражающее разнообразие живых организ­мов (растений, животных, грибов и микроорганизмов). В настоящее время описано около 1,7 миллиона видов, хотя их общее число, по не­которым оценкам, составляет до 50 млн.;

- разнообразие экосистем охватывает различия между типами экосис- 1Ш, разнообразием сред обитания и экологических процессов. Отмечают разнообразие экосистем не только по структурным и функциональным составляющим, но и по масштабу—от микробиогеоценоза до биосферы.

Иногда в отдельную категорию выделяют разнообразие ландшафтов, отражающее особенности территориального устройства и влияние местных, региональных и национальных культур общества.

Все типы биологического разнообразия взаимосвязаны между собой: генетическое разнообразие обеспечивает разнообразие видов. Разнообразие экосистем и ландшафтов создает условия для образования новых видов. Повышение видового разнообразия увеличивает общий генетический потенциал живых организмов биосферы. Каждый вид вносит свой вклад в разнообразие – с этой точки зрения не существует бесполезных и вредных видов.

Распределение видов по поверхности планеты неравномерно. Разнообразие видов в естественных средах обитания максимально в тропической зоне и уменьшается с увеличением широты. Самые бога­тые видовым разнообразием экосистемы - дождевые тропические леса, которые занимают около 7 % поверхности планеты и содержат более чем 90 % всех видов.

В геологической истории Земли в биосфере постоянно происходило возникновение и исчезновение видов—все виды имеют конечное время существования. Вымирание компенсировалось появлением новых ви­дов, и в результате, общее число видов в биосфере возрастало. Выми­рание видов — естественный процесс эволюции, который происходит без вмешательства человека.

В настоящее время под воздействием антропогенных факторов про­исходит сокращение биологического разнообразия за счет элиминации (вымирания, уничтожения) видов. В последнее столетие под влиянием человеческой деятельности скорость вымирания видов во много раз превысила естественную (по некоторым оценкам в 40000 раз). Проис­ходит необратимое и некомпенсированное разрушение уникального генофонда планеты.

Элиминация видов в результате деятельности человека может происходить по двум направлениям — прямое истребление (охота, про­мысел) и косвенное (разрушение среды обитания, нарушение трофи­ческих взаимодействий). Чрезмерный промысел — наиболее очевидная прямая причина прямого сокращения численности видов, однако он гораздо менее влияет на вымирание, чем косвенные причины измене­ния среды обитания (например, вследствие химического загрязнения реки или вырубки леса).

Для учета видов, находящихся на грани вымирания, во многих странах создаются Красные Книги — списки редких и исчезающих ви­дов живых организмов. Для сохранения и поддержания биологического разнообразия создаются особо охраняемые природные территории (за­поведники, национальные парки и др.), генетические банки данных. Сохранение отдельного вида возможно лишь при условии охраны его среды обитания со всем комплексом входящих в нее видов, климати­ческих, геофизических и других условий. Особую роль играет при этом сохранение средообразующих видов (видов-эдификаторов), которые формируют внутреннюю среду экосистемы. Создание особо охраня­емых природных территорий направлено на охрану не только отдельных видов, но и целых комплексов и ландшафтов.

Заповедники служат также для оценки и мониторинга состояния биоразнообразия. Единой системы мониторинга состояния биоразно­образия на сегодняшний день в России не существует. Наиболее полный и постоянный контроль за изменением компонентов биоразнообразия осуществляется в заповедниках. Ежегодно заповедники готовят отчеты о состоянии экосистем («Летописи природы») - сводки данных о состоянии заповедных территорий, охраняемых популяций растений И Животных. Некоторые заповедники ведут «Летописи природы» более '11 лет, которые включают в себя непрерывные ряды данных по чис­ленности животных, биологическому разнообразию, динамике эко­систем, а также приводятся данные по климатическим наблюдениям.

Часть заповедников России входит в состав международной сети биосферных заповедников, специально созданных для мониторинга состояния биоразнообразия, климатических, биогеохимических и других процессов в масштабах Биосферы.

Причин необходимости сохранения биоразнообразия много: потребность в биологических ресурсах для удовлетворения нужд человечества (пища, материалы, лекарства и др.), этический и эстетичес­кий аспекты (жизнь самоценна) и т.д. Однако главная причина сохра­нения биоразнообразия состоит в том, что оно выполняет ведущую роль и обеспечении устойчивости экосистем и Биосферы в целом (поглощение загрязнений, стабилизация климата, обеспечение пригодных для жизни условий). Биоразнообразие выполняет регулирующую функцию в осуществлении всех биогеохимических, климатических и других Процессов на Земле. Каждый вид, каким бы незначительным он не казался, вносит свой вклад в обеспечение устойчивости не только «родной» локальной экосистемы, но и Биосферы в целом.

 

 


convention; distribution; latitude (широта); genesis, emergence (возникновение); reduction (сокращение); irreversible (необратимый); extermination (исчезновение); on the verge of extinction; national park, reserve (заповедник).

 

VII. Read the text carefully, without a dictionary. While reading, pay special attention to the words that you don’t know: look carefully at the context and see if you can get the idea of what they mean. After reading answer the question: what problem is life on the Earth is now faced with? Point out the information that was new to you. Summarize the text.

Biodiversity or Biological Diversity is the sum of all the different species of animals, plants, fungi, and microbial organisms living on the Earth and the vari­ety of habitats in which they live. Scientists estimate that upwards of 10 million and some suggest more than 10б million of different species inhabit the Earth.

I ach species is adapted to its unique niche in the environment, from the peaks of mountains to the depths of deep-sea hydrothermal vents, and from polar ice caps to tropical rain forests.

Biodiversity underlies everything from food production to medical research. Humans of the world overuse at least 40,000 species of plants and animals on a daily basis. Many people around the world still depend on wild species for some or all of their food, shelter, and clothing. All of our domesticated plants and animals came from wild-living ancestral species. Close to 40 percent of the pharmaceuticals used in the United States are either based on or synthesized from natural compounds found in plants, animals, or microorganisms.

The array of living organisms found in a particular environment together with the physical and environmental factors that affect them is called an ecosystem. Healthy ecosystems are vital to life: they regulate many of the chemi­cal and climatic systems that make available clean air and water and plentiful oxygen. Forests, for example, regulate the amount of carbon dioxide in the air, produce oxygen as a byproduct of photosynthesis (the process by which plants convert energy from sunlight into carbohydrate energy), and control rainfall and soil erosion. Ecosystems, in turn, depend on the continued health and vitality of the individual organisms that compose them. Removing just one species from an ecosystem can prevent the ecosystem from operating optimally.

Perhaps the greatest value of biodiversity is yet unknown. Scientists have discovered and named only 1.75 million species and less than 20 percent of those are estimated to exist. And of those identified, only a fraction has been examined for potential medicinal, agricultural, or industrial value. Much of the Earth’s great biodiversity is rapidly disappearing, even before we know what is missing. Most biologists agree that life on Earth is now faced with the most severe extinction episode since the event that drove the dinosaurs to extinction 65 million years ago. Species of plants, animals, fungi, and microscopic organisms such as bacteria are being lost at such alarming rates that biologists estimate that three species go extinct every hour. Scientists around the world are cataloging and studying global biodiversity in hopes that they might better understand it, or at least slow the rate of loss.

 

IX. Talking points:

 

1. Biodiversity as distinct from other forms of diversity.

2. Biodiversity problem.

 

 

Unit 4.

Есological Niche

The concept of the ecological niche is an important one; it helps us to understand how organisms in an ecosystem interact with each other. The concept is described by Odum as follows:

I he ecological niche of an organism depends not only on where it lives but also on what it does. By analogy, it may be said that the habitat is the organism’s «address», and the niche is its «profession», biologically speaking.

Here are a few examples to help you understand what we mean when we (ecologists) use the term «ecological niche»:

Oak trees live in oak woodlands; that’s common sense. The oak woodland is the habitat. So if Odum was writing a letter to an oak tree he would address the letter to:

Sir Deciduous Oak Tree,

The Oak Forest,

England,

U.K.

What do oak trees do? If you can answer that question you know the oak roes «profession» or its ecological niche. Perhaps you think that oak trees just (and there looking pretty and not doing very much, but think about it.

Oak trees:

1. absorb sunlight by photosynthesis;

2. absorb water and mineral salts from the soil;

3. provide shelter for many animals and other plants;

4. act as a support for creeping plants;

5. serve as a source of food for animals;

6. cover the ground with their dead leaves in the autumn.

These six things are the «profession» or ecological niche of the oak tree; you can think of it as being a kind of job description. If the oak trees were cut down or destroyed by fire or storms they would no longer be doing their job and this would have a disastrous effect on all the other organisms living in the same habitat.

Hedgehogs in the garden also have an ecological niche. They rummage about in the flowerbeds eating a variety of insects and other invertebrates which live underneath the dead leaves and twigs in the flowerbeds. That is their pro­fession. They are covered in sharp spines which protect them from predators, so being caught and eaten is not a part of their job description.

However, hedgehogs cannot groom themselves properly. All those spines on their backs make a superb environment or microhabitat for fleas and ticks.

Hedgehogs put nitrogen back into the soil when they urinate! I don’t know how much nitrogen they put into the soil but it probably helps the plants if they do. I think that they eat my slugs, so that reduces the effect which slugs have on the flowers.

So the idea of an ecological niche is very simple. You just need to know where the animal or plant lives and what it does.

Exercises

A. Comprehension

I. Give the author’s definition of the ecological niche. Mention the comparison of the author and your opinion on the reasons.

II. Prove the importance of the concept of the ecological niche. Illustrate it in some examples:

a) determine the oak trees’ habitat and profession;

b) define the ecological niche of hedgehogs.

III. Write a summary of the text making special mention of the facts you personally found new, interesting, etc.

B. Vocabulary

IV. Give Russian equivalents of the following expressions:

woodlands oak hedgehog

to absorb soil creeping plant

disastrous effect to rummage flowerbed

tick invertebrate twig

to groom sharp spine flea

 

V. Match these definitions with the words from Exercise 4.

1) ground, earth, esp. the upper layer of earth in which plants, trees, etc. grow,

2) to take or suck in;

3) needle-like part on some animals or plants with a fine Cutting edge;

4) a small jumping insect that feeds on the blood of human beings and some animals;

5) a plot of land on which flowers are grown;

6) turn thins over, move things about, while looking for something;

7) a small spider-like parasite that fastens itself on the skin and sucks blood;

8) an insect-eating animal covered with spines, that rolls itself into up a ball

to defend itself;

9) to clean the fur and skin;

10) not having a backbone or spinal column;

11) growing along the ground (of plants), over the surface of a wall, etc.;

12) a small new, young growth on or at the end of a plant or bush;

13) an area of land covered with growing trees (not so intensive as a forest);

14) the result, which causes great or sudden misfortune; terrible accident.

 

VI. Use the words from exercise 1 in your own sentences or situations.

 

C.Reading and Discussion

Read the text carefully, without a dictionary. While reading, pay special attention to the words that you don't know: look carefully at the context and see if you can get the idea of what they mean. After feeding answer the questions: 1) What definition of the niche does G.E. Hutchinson suggest? 2) What is the distinction between fundamental and realized niches? Point out the information that was new to you. Summarize the text.

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

G.E. Hutchinson (1958) suggested that the niche could be modeled as an imaginary space with many dimensions, in which each dimension or axis represents the range of some environmental condition or resource that is re­quired by the species. Thus, the niche of a plant might include the range of temperatures that it can tolerate, the intensity of light required for photosynthesis, specific humidity regimes, and minimum quantities of essential soil nutrients for uptake.

A useful extension of the niche concept is the distinction between fundamental and realized niches. The fundamental niche of a species includes the total range of environmental conditions that are suitable for existence without the influence of interspecific competition or predation from other species. The realized niche describes that part of the fundamental niche actually occupied by the species.

 

Molstyre


Temperature

 

 

The following diagram shows a hypothetical situation where a species dis­tribution is controlled by just two environmental variables: temperature and moisture. The green and yellow areas describe the combinations of temperature and moisture that the species requires for survival and reproduction in its habitat. This resource space is known as the fundamental niche. The green area describes the actual combinations of these two variables that the species utilizes in its habitat. This subset of the fundamental niche is known as the realized niche.

 

VII. Retell the following text in English. Mention the points of difference between the English and Russian texts in the presentation and interpretation of facts concerning ecological niche.

Экологическая ниша — место, занимаемое видом (точнее — его попу­ляцией) в сообществе (биоценозе). Взаимодействие данного вида (по­пуляции) с партнёрами по сообществу, в которое он входит в качестве сочлена, определяет его место в круговороте веществ, обусловленном пищевыми и конкурентными связями в биоценозе. Термин «экологическая ниша» предложен американским учёным Дж. Гринеллом (1917). Трактовка экологической ниши как положения вида в цепях питания одного или нескольких биоценозов была дана английским экологом Ч.Элтоном (1927). Подобное толкование понятия «экологическая ниша» позволяет дать количественную характеристику экологической ниши для каждого вида или для его отдельных популяций. Для этого сопоставляют в системе координат обилие вида (число особей или биомассу) с показателями температуры, влажности или любого другого фактора среды. Таким путём можно выделить зону оптимума и пределы выносимых видом отклонений — максимум и минимум каждого фактора или совокупности факторов. Как правило, каждый вид занимает определённую экологическую нишу, к существованию в которой он приспособлен всем ходом эволюционного развития. Место, занимаемое видом (его популяцией) в пространстве (пространственная экологическая ниша), чаще называют местообитанием.

Растения и почва

 

Рассмотрите взаимодействие между двумя факторами среды на при­мере простого графика, отражающего зависимость распространения некоторых кустарников и травянистых растений от содержания в почве кальция и органического вещества. У каждого вида проявляются раз­личные предпочтения: черемуха встречается только в пределах узкого диапазона содержания кальция; распространение волчьей лапы, на­против, ограничено строго определенным содержанием органического вещества; разные виды фиалки выдерживают более широкий диапазон органики и кальция. Отметьте, что предпочтения у фиалок перекрыва­ются мало: белая фиалка растет на почве с более высокой концентра­цией кальция и низкой — органики. Поэтому в природе эти виды встречаются в разных местах, избегая конкуренции друг с другом. Этот факт служит иллюстрацией одного из фундаментальных положений экологии — принципа конкурентного исключения (принципа Гаузе): если два вида обладают одинаковыми требованиями к качеству среды обитания (произрастания), то рано или поздно один из видов неиз­бежно вытесняет другой. Поэтому эволюция близких видов обычно идет таким образом, что у них формируются несколько различные предпоч­тения по отношению к внешней среде.

 

 


coordinate system; rate (показатель); limit of tolerance (предел откло­нений); content (содержание); maheleb (черемуха); violet (фиалка); the principle of competitive exclusion (принцип конкурентного исключения); external environment (внешняя среда).

IX. Translate the text without a dictionary.

In ecology, a niche is a term describing the relational position of a species or population in an ecosystem. More formally, the niche includes how a population responds to the abundance of its resources and enemies (e.g., by growing when resources are abundant, and predators, parasites and pathogens are scarce) and how it affects those same factors (e.g., by reducing the abun­dance of resources through consumption and contributing to the population growth of enemies by falling prey to them). The abiotic or physical environment is also part of the niche because it influences how populations affect, and are affected by, resources and enemies.

The description of a niche may include descriptions of the organism’s life history, habitat, and place in the food chain. According to the competitive exclusion principle, no two species can occupy the same niche in the same environment for a long time.

The term «Niche» was coined by the naturalist Joseph Grinnell in 1917, in his paper «The niche relationships of the California Thrasher». However, it wasn’t until 1927 that Charles Elton, a British ecologist, gave the first working definition of the niche concept. He was credited of saying «when an ecologist sees a badger, they should include in their thoughts some definitive idea of the animal's place in the community to which it belongs, just as if they had said «I here goes the vicar».

The niche concept was popularized by the zoologist G. Evelyn Hutchinson in 1957. Hutchinson wanted to know why there are so many different types of organisms in any one habitat.

The full range of environmental conditions (biological and physical) under which an organism can exist describes its fundamental niche. As a result of pressure from, and interactions with, other organisms (e.g. superior competitors) species are usually forced to occupy a niche that is narrower than this and to which they are mostly highly adapted. This is termed the realized nil hr G.E.Hutchinson also defined the ecological niche as a «Hypervolume». This term defines the multi-dimensional space of resources (i.e., light, nutrients, structure, etc.) available to (and specifically used by) organisms.

Different species can hold similar niches in different locations and the same species may occupy different niches in different locations. The Australian grasslands species, though different from those of the Great Plains grasslands, occupy the same niche. Once a niche is left vacant, other organisms can fill into that position. For example, the niche that was left vacant by the extinction of the tarpan has been filled by other animals (in particular a small horse breed, the konik). When plants and animals are introduced into a new environment, they can occupy the new niches or niches of native organisms, outcompete the indigenous species, and become a serious pest.

 

 

X. Talking points:

1. The concept of ecological niche and its types.

2. The origin of the term and its brief history.

3. The examples of the term’s application.

 

Unit 5.

An Ecosystem Engineer

An ecosystem engineer is an organism that creates, modifies and maintains habitats. Most organisms alter their physical environments in some way, so the term ecosystem engineer is applied only to certain key species that have a profound and wide-ranging influence, changing the distribution and diversity of flora and fauna in their locality. Scientists describe two types of ecosystem engineers.

Autogenic engineers modify the environment using their own physical struc­tures. Trees and corals are two important examples.

Allogenic engineers transform living or non-living material from one form to another using mechanical or other means. The beaver is second only to humans in this capacity.

The beaver engineers its environment in several ways, most obviously by cutting trees and building dams, but the building of lodges and canals is also important.

It is the only species besides humans that is capable of cutting down mature trees. Beaver activity changes the forest structure and diversity of tree species. The animal will use a wide range of trees, but when given a choice will cut its preferred foods, particularly poplar and willow. Willows and maples send up shoots from the cut stumps, but poplars and some other tree species do not. Beavers often clear-cut the areas around their ponds. In other cases, mature trees may become replaced by a dense undergrowth of willow or other shoots. Other tree species become scarce and may be replaced by ones that the beaver does not favour, such as ash. Other timber along the watercourse may be killed by flooding.

In one year a family of six can consume 0.4 hectares (1 acre) of poplar trees, and is estimated to fell one metric ton of wood. If the family exhausts its food source, it will move to a new location.

This tree-cutting alters forest succession. If the beaver creates forest open­ings, sun-loving plants may take hold, converting a mature forest to an early successional stand. Sometimes, however, the beaver hastens forest maturity by electing willows and poplars, which are early succession trees, allowing the rapid development of understory saplings such as fir and spruce.

Dam-building changes the flow of water through the stream. Beaver re­quire deep slow-moving water for storing food, constructing lodges and mov­ing «round safely. This is why they build dams. The still water in a beaver pond attracts species normally associated with lakes rather than streams, while species dependent on fast water die out or move elsewhere.

Exercises

A.Comprehension

I. Answer these questions.

1. What organisms can be classified as ecosystem engineers?

2. How many types of ecosystem engineers exist? Characterize each one.

3. What type of ecosystem engineers does the beaver refer to? Why?

4. What foods are its preferred ones? What does this preference lead to?

5. How many trees can a family of six can consume in one year?

6. How does dam-building change the flow of water through the stream?

 

II. Write a summary of the text making special mention of the facts you personally found new, interesting, etc.

 

B.Vocabulary

III. Give Russian equivalents of the following expressions:

 

to create to modify to maintain

profound wide-ranging influence autogenic

allogenic most obviously coral

lodge poplar willow

mature tree stump undergrowth

timber to hasten rapid development

understory sapling spruce

pond to store food stream

 

IV. Find synonyms of these expressions among the words and word combinations in the previous exercise.

1) pool, lake;

2) wood;

3) base, remnant of a tree;

4) to change, transform;

5) brushwood, bushes, undergrowth;

6) small house;

7) to speed up, to rush, to hurry;

8) extensive, comprehensive, all-embracing effect or impact;

9) to make, produce, generate;

10) deep, insightful;

11) to stock up, amass, save;

12) plantlet, sprout, seedling;

13) fully grown tree;

14) quick, fast progress;

15) fur tree;

16) to preserve, uphold, keep up.

 

V. Recall the sentences in the text, where each of Exercise 3 expressions is used.

 

Unit 6.

The Ecosystem Concept

The first principle of ecology is that each living organism has an ongoing and continual relationship with every other element that makes up its environment. An ecosystem can be defined as any situation where there is interac tion between organisms and their environment.

An ecosystem, a contraction of «ecological» and «system», refers to the collection of components and processes that comprise, and govern the behavior of, юте defined subset of the biosphere. The term is generally understood to refer to all biotic and abiotic components, and their interactions with each other, in some defined area, with no conceptual restrictions on how large or small that area can be.

There are two main components of all ecosystems: abiotic and biotic.

Abiotic, or nonliving, components of an ecosystem are its physical and chemical components, for example, rainfall, temperature, sunlight, and nutrient supplies.

One of the problems with modern society is that it changes environmental conditions, making regions hotter or drier, for example. Such changes can make life more difficult, if not impossible, for other organisms.

Biotic components of an ecosystem are its living things — fungi, plants, animals and microorganisms. Organisms live in populations, groups of the same species occupying a given region. Populations never live alone in an ecosystem. They always share resources with others, forming a community (a group of organisms living in the given area).

The ecosystem is composed of two entities, the entirety of life, the biocoenosis and the medium that life exists in, the biotope. Within the ecosystem, species are connected by food chains or food webs. Energy from the sun, captured by primary producers via photosynthesis, flows upward through the chain to primary consumers (herbivores), and then to secondary and tertiary consumers (carnivores), before ultimately being lost to the system as waste heat. In the process, matter is incorporated into living organisms, which return their nutrients to the system via decomposition, forming biogeochemical cycles such as the carbon and nitrogen cycles.

The concept of an ecosystem can be applied to units of variable size, such as a pond, a field, or a piece of deadwood. A unit of smaller size is called a microecosystem. For example, an ecosystem can be a stone and all the life under it. A mesoecosystem could be a forest, and a macroecosystem a whole ecoregion, with its drainage basin.

The main questions when studying an ecosystem are:

· Whether the colonization of a barren area could be carried out.

· Investigation of the ecosystem's dynamics and changes.

· The methods of which an ecosystem interacts at local, regional and global scale.

· Whether the current state is stable.

· Investigating the value of an ecosystem and the ways and means that interaction of ecological systems provide benefit to humans, especially in the provision of healthy water.

Ecosystems have become particularly important politically, since the Convention on Biological Diversity — ratified by more than 175 countries — defines «the protection of ecosystems, natural habitats and the maintenance of viable populations of species in natural surroundings» as one of the binding commitments of the ratifying countries. This has created the political necessity to spatially identify ecosystems and somehow distinguish among them. The CBD defines an «ecosystem» as a «dynamic complex of plant, animal and micro-organism communities and their non-living environment interacting as a functional unit».

For this purpose, ecosystems can be characterized and mapped as physiognomic ecological units, originally developed for vegetation classification. Each vegetation structure reflects ecological conditions. Each ecosystem thus defined, hosts assemblages of species with survival strategies that can survive under its conditions. This is not only true for plant species, but for all species, flora, fauna and fungi alike, as each species responds to the characteristic ecological conditions of each location. This principle allows us to map ecosystems using the UNESCO physiognomic ecological classification system, the Land Cover Classification Systems (LCCS) developed by the FAO and the United States National Vegetation Classification system (USNVC). The size and scale of an ecosystem can vary widely. It may be a whole forest, a community of bacteria and algae in a drop of water or even the geobiosphere Им-11 As most of these borders are not rigid, ecosystems tend to blend into each other. As a result, the whole earth can be seen as a single ecosystem, while a lake can be divided into several ecosystems, depending on the scale used..

Early conceptions of this unit showed a structured functional unit in equilibrium of energy and matter flows between its constituent elements. Others considered this vision limited, and preferred to understand an ecosystem in terms of cybernetics. From this point of view an ecological system is a functional dynamic organization, or what was also called «steady state». Steady state is understood as the phase of an ecological system’s evolution when the organisms are «balanced» with each other and their environment. This balance is achieved or «regulated» through various types of interactions, such as predation, parasitism, mutualism, commensalism, competition, and amensalism. Introduction of new elements, whether abiotic or biotic, into an ecosystem tend to have a disruptive effect. In some cases, this can lead It ecological collapse and the death of many native species. The branch of ecology that gave rise to this view has become known as systems ecology. Under this deterministic vision, the abstract notion of ecological health attempts to measure the robustness and recovery capacity for an ecosystem; that U, how far the ecosystem is away from steady state.

Ecosystems are often classified by reference to the biotopes concerned. The following ecosystems may be defined:

· As continental ecosystems, such as forest ecosystems, meadow ecosystems such as steppes or savannas), or agro-ecosystems

· As ecosystems of inland waters, such as lentic ecosystems such as lakes or ponds; or lotic ecosystems suc





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