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5. The Law of Limiting Factors was first presented by Justus von Liebig in 1840 in connection with his observations regarding the effects of chemical nutrients on plant growth. He observed that restricting any one of the many different nutrients at any given time had the same effect: it limited growth. Thus, this law is also called Liebig's Law of Minimums. Observations since Liebig's time, however, show that his law has much broader application.

СBeyond its application to all abiotic factors, it may be applied to biotic factors as well.

6. In summary, the biosphere consists of a great variety of environments, both aquatic and terrestrial. In each environment we find plants, animal, and иmicrobial species that are adapted to all the abiotic factors and also to each other in various feeding and nonfeeding relationships. Such environment supports a more or less unique grouping of organisms interacting with each other and with the environment in a way that perpetuates or sustains the entire group.бАThat is, each environment with the species it supports is an ecosystem. Every ecosystem is interconnected with others through ecotones and through some species that cross from one system to another. At the same time, each species and, as a result, each ecosystem, is kept within certain bounds by limiting factors. That is, the spread of each species is at some point limited by its not being able to tolerate particular conditions, compete with other species, or cross some physical barrier.

7. A major concern of many environmentalists is how altering any factor, abiotic or biotic, may upset these limits and have far-reaching consequences through a ripple effect. RecognizingДthat everything in the biosphere is interconnected leads to the conclusion that nothing can be changed without affecting everything else to a greater or lesser degree. Obviously, humans have changed and are continuing to change things on a very large scale. What will these changes bring? Many environmentalists, including a number of scientists, promote the idea that we may beИon the verge of a sudden and catastrophic "collapse of the biosphere" in which most if not all life may perish. On the other hand, cornucopians, also including a number of scientists, point out that there is no solid evidence to support such a "doomsday scenario"; much less that it is imminent. Indeed, they argue that all our experience to date should lead to the quite opposite conclusion: Humans have already caused the extinction of thousands of species and made manifold changes over most of the earth, but we and the biosphere are still doing well. Therefore, they maintain that continuing development as we have been does not pose an environmental threat.

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6. Choose the correct answer.

1. What is the main idea of the article?

a. The biosphere consists of a great variety of environments, both aquatic and terrestrial.

Сb. Every ecosystem has two "sides": the organisms on one hand and the environmental factors on the other.

c. Humans have changed and are continuing to change things on a very large scale.

2.According to paragraph 2, the environment involves the interplay of:

a.rainfall, temperature, light, water and wind;

b.chemical nutrients, pH, salinity and fire;

c.many physical and chemical, or abiotic factors.

3.The difference in response to environmental factors determines

a.which organisms do or don't survive;

b.which species may or may not occupy a given region;

c.the degree to which each is present or absent.

4.The Law of Limiting Factors includes

a.any factor that affects the organism;

b.the problem of "too little";

c.the problem of "too much".

5.In paragraph 5, the Law of Limiting Factors was first presented

a.in connection with the observations regarding the effects of chemical nutrients on plant growth;

b.by Justus von Liebig;

c.in 1840.

6.Liebig's Law of Minimums may be applied to

a.our agricultural crops;

b.biotic factors;

c.all abiotic factors.и И

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PART IV

THE CIVIL ENGINEERING FACULTY

2. Read the words and study them by heart. Make up three sentences with the new words.

municipal – мун ц пальный, городской utilities – коммунальные сооружения (услуги)

insulation – изоляция

3. Pay attention to the pronunciation of the letter U in different letter combinations.

[ju:] students, municipal, utility, computed, insulation, superintendent, manufacturing, universal, curriculum;

[u:] influence, solution;

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[Λ] rupture, structures, construction, subject, study; [ə] faculty, structures, curriculum, manufacturing.

4. Read and translate the text. How many parts can it be divided into? Entitle each part.

СTHE CIVIL ENGINEERING FACULTY

The students of this faculty are trained in eight qualifications, among

which are building and economical specialties. The former are Architecture, Industrial and Civil Engineering, Building Design, Manufacturing of Building Structures, Architectural Design, Construction of Unique Buildings

иengineers, architects, specialists, bachelors of Science and masters of Science.

and Structures, Heat and Gas Supply and Ventilation. The latter one is Real

Estate Expertise. In fact, the faculty has already got the status of an institute

Structures,бАTheoretical Mechanics and Strength of Materials. The latter is one of the most important subjects, becauseДit deals with different kinds of loads. A building engineer should take into account the loadings which influence

(The Engineering Construction Institute). Its graduates get diplomas of

The speciality of building engineer is the most universal and wide-spread.

In order to be a competent specialist the students of the faculty study a

number of specialized subjects: Building Materials, Geodesy, Geology, Soil

Mechanics, Bases and Foundations, Engineering Systems of Buildings and Structures, Reinforced Concrete and Masonry Structures, Wood and Plastic

the building; he should be able to calculate the computed and limited strength and stresses of a building.

The students of the faculty study various structures and buildings, their parts and elements and also construction technology.ИThe structures and buildings are usually built of concrete, steel and wood. A structure consists of a basement, walls, partitions, floors, ceilings and a roof. All this the students study by listening to courses of lectures, as well as having practice at construction sites, where they get practical experience. The students of the faculty also get acquainted with Architecture; they study the architectural styles and various architectural structures.

The construction of any building, house or office is connected with utilities, lighting, heating, ventilation, water supply and sewerage. Besides, the students of the faculty have lectures on Construction Physics which deals with acoustics, heat insulation and microclimate. A good building engineer should follow the appearance of new building materials, technologies and achievements of modern construction.

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