Geography. A complete guide to preparing for the exam

In order to determine basic properties biosphere, you must first understand what we are dealing with. What is the form of its organization and existence? How does it work and interact with the outside world? Ultimately, what is it?

From the appearance of the term at the end of the 19th century to the creation of a holistic doctrine by the biogeochemist and philosopher V.I. Vernadsky, the definition of the concept of "biosphere" has undergone significant changes. It has moved from the category of a place or territory where living organisms live to the category of a system consisting of elements or parts, functioning according to certain rules to achieve a specific goal. It is on how to consider the biosphere that it depends on what properties are inherent in it.

The term is based on ancient Greek words: βιος - life and σφαρα - sphere or ball. That is, it is some shell of the Earth, where there is life. Earth, as an independent planet, according to scientists, arose about 4.5 billion years ago, and a billion years later life appeared on it.

Archean, Proterozoic and Phanerozoic eon. Eons are made up of eras. The latter consists of the Paleozoic, Mesozoic and Cenozoic. Eras from periods. Cenozoic from the Paleogene and Neogene. Periods from epochs. The current - Holocene - began 11.7 thousand years ago.

Borders and layers of propagation

The biosphere has a vertical and horizontal distribution. Vertically, it is conventionally divided into three layers where life exists. These are the lithosphere, hydrosphere and atmosphere. The lower boundary of the lithosphere reaches 7.5 km from the Earth's surface. The hydrosphere is located between the lithosphere and the atmosphere. Its maximum depth is 11 km. The atmosphere covers the planet from above and life in it exists, presumably, at an altitude of up to 20 km.

In addition to vertical layers, the biosphere has a horizontal division or zoning. This change natural environment from the Earth's equator to its poles. The planet has the shape of a ball and therefore the amount of light and heat entering its surface is different. The largest areas are geographic zones. Starting from the equator, it goes first equatorial, above tropical, then temperate, and finally, near the poles - arctic or antarctic. Inside the belts are natural zones: forests, steppes, deserts, tundras, and so on. These zones are characteristic not only for land, but also for the oceans. The horizontal location of the biosphere has its own altitude. It is determined by the surface structure of the lithosphere and differs from the foot of the mountain to its top.

To date, the flora and fauna of our planet has about 3,000,000 species, and this is only 5% of the total number of species that have managed to "live" on Earth. About 1.5 million animal species and 0.5 million plant species have found their description in science. There are not only undescribed species, but also unexplored regions of the Earth, the species content of which is unknown.

Thus, the biosphere has a temporal and spatial characteristic, and the species composition of living organisms that fills it changes both in time and in space - vertically and horizontally. This led scientists to the conclusion that the biosphere is not a planar structure and has signs of temporal and spatial variability. It remains to determine, under the influence of what external factor, it changes in time, space and structure. That factor is solar energy.

If we accept that the species of all living organisms, regardless of the spatial and temporal framework, are parts, and their totality is the whole, then their interaction with each other and with the external environment is a system. L von Bertalanffy and F.I. Peregudov, defining a system, argued that it is a complex of interacting components, or a set of elements that are in relationship with each other and with the environment, or a set of interconnected elements that are isolated from the environment and interact with it as a whole.

System

The biosphere as a single integral system can be conditionally divided into its constituent parts. The most common such division is species. Each type of animal or plant is taken as constituent part systems. It can also be recognized as a system, with its own structure and composition. But the species does not exist in isolation. Its representatives live in a certain territory, where they interact not only with each other and the environment, but also with other species. Such a residence of species, in one area, is called an ecosystem. The smallest ecosystem, in turn, is included in the larger one. That in even more and so to the global - to the biosphere. Thus, the biosphere, as a system, can be considered as consisting of parts, which are either species or biospheres. The only difference is that a species can be identified because it has features that distinguish it from others. It is independent and in other types - parts are not included. With biospheres, such a distinction is impossible - one part of the other.

signs

The system has two more significant features. It was created to achieve a specific purpose and functioning whole system more effective than each of its parts separately.

Thus, the properties as a system, in its integrity, synergy and hierarchy. Integrity lies in the fact that the connections between its parts or internal connections are much stronger than with the environment or external ones. Synergy or systemic effect is that the capabilities of the entire system are much greater than the sum of the capabilities of its parts. And, although each element of the system is a system itself, nevertheless, it is only a part of the general and larger one. This is its hierarchy.

The biosphere is dynamic system, which changes its state under external influence. It is open because it exchanges matter and energy with the environment. It has a complex structure, as it consists of subsystems. And finally, it is a natural system - formed as a result of natural changes over many years.

Thanks to these qualities, she can regulate and organize herself. These are the basic properties of the biosphere.

In the middle of the 20th century, the concept of self-regulation was first used by the American physiologist Walter Cannon, and the English psychiatrist and cybernetician William Ross Ashby introduced the term self-organization and formulated the law of required diversity. This cybernetic law formally proved the need for a large species diversity for the stability of the system. The greater the diversity, the higher the probability of the system to maintain its dynamic stability in the face of large external influences.

Properties

Responding to external influence, resisting and overcoming it, reproducing itself and restoring, that is, maintaining its internal constancy, such is the goal of a system called the biosphere. These qualities of the whole system are built on the ability of its part, which is the species, to maintain a certain number or homeostasis, as well as each individual or living organism to maintain its physiological conditions - homeostasis.

As you can see, these properties developed in her under the influence and to counteract external factors.

The main external factor is solar energy. If the number of chemical elements and compounds is limited, then the energy of the Sun is constantly supplied. Thanks to it, the migration of elements along the food chain from one living organism to another and the transformation from an inorganic state to an organic one and vice versa occurs. Energy accelerates the course of these processes inside living organisms and, in terms of the reaction rate, they occur much faster than in the external environment. The amount of energy stimulates the growth, reproduction and increase in the number of species. Variety, in turn, allows for additional resistance. external influence, as there is a possibility of duplication, safety net or replacement of species in the food chain. The migration of elements will thus be additionally ensured.

Human influence

The only part of the biosphere that is not interested in increasing the species diversity of the system is man. He strives in every possible way to simplify ecosystems, because in this way he can more effectively monitor and regulate it, depending on his needs. Therefore, all biosystems artificially created by man or the degree of his influence, on which is significant, are very scarce in terms of species. And their stability and ability to self-healing and self-regulation tends to zero.

With the advent of the first living organisms, they began to change the conditions of existence on Earth to suit their needs. With the advent of man, he already began to change the biosphere of the planet so that his life was as comfortable as possible. It is comfortable, because we are not talking about survival or saving life. Following logic, something should appear that will change the person himself for its own purposes. I wonder what it will be?

Video - Biosphere and noosphere

Atmosphere: The presence of the atmosphere around the globe determines the general thermal regime of the surface of our planet, protects it from harmful cosmic and ultraviolet radiation. Atmospheric circulation affects local climatic conditions, and through them - on the regime of rivers, soil and vegetation cover and on the processes of relief formation.

The modern gas composition of the atmosphere is the result of a long historical development of the globe. It is mainly a gas mixture of two components - nitrogen (78.09%) and oxygen (20.95%). Normally, it also contains argon (0.93%), carbon dioxide (0.03%) and small amounts of inert gases (neon, helium, krypton, xenon), ammonia, methane, ozone, sulfur dioxide and other gases. Along with gases, the atmosphere contains solid particles coming from the Earth's surface (for example, products of combustion, volcanic activity, soil particles) and from space (cosmic dust), as well as various products of plant, animal or microbial origin. In addition, water vapor plays an important role in the atmosphere.

The three gases that make up the atmosphere are of greatest importance for various ecosystems: oxygen, carbon dioxide and nitrogen. These gases are involved in the main biogeochemical cycles.

The modern atmosphere contains hardly a twentieth of the oxygen available on our planet. The main reserves of oxygen are concentrated in carbonates, organic substances and iron oxides, part of the oxygen is dissolved in water.

Hydrosphere: the totality of all the water resources of the Earth. It forms its discontinuous water shell. The average depth of the ocean is 3800 m, the maximum (Marian Trench Pacific Ocean) - 11.034 meters. About 97% of the mass of the hydrosphere is saline ocean water, 2.2% is glacier water, the rest is groundwater, lake and river fresh water. The region of the biosphere in the hydrosphere is represented in its entire thickness, however, the highest density of living matter falls on the surface layers heated and illuminated by the rays of the sun, as well as coastal zones.

IN general view accepted division of the hydrosphere into the oceans, continental waters and groundwater. Most of the water is concentrated in the ocean, much less - in the continental river network and groundwater. There are also large reserves of water in the atmosphere, in the form of clouds and water vapor. Over 96% of the volume of the hydrosphere is seas and oceans, about 2% is groundwater, about 2% is ice and snow, and about 0.02% is land surface water. Part of the water is in a solid state in the form of glaciers, snow cover and in permafrost representing the cryosphere.

surface water, occupying a relatively small share in the total mass of the hydrosphere, nevertheless play an important role in the life of the terrestrial biosphere, being the main source of water supply, irrigation and watering. Moreover, this part of the hydrosphere is in constant interaction with the atmosphere and the earth's crust.

Lithosphere: solid shell of the earth. It consists of the earth's crust and the upper part of the mantle, up to the asthenosphere, where the seismic wave velocities decrease, indicating a change in the plasticity of the rocks. In the structure of the lithosphere, mobile areas (folded belts) and relatively stable platforms are distinguished.

Blocks of the lithosphere - lithospheric plates - move along the relatively plastic asthenosphere. The section of geology on plate tectonics is devoted to the study and description of these movements.

The lithosphere under oceans and continents varies considerably. The lithosphere under the continents consists of sedimentary, granite and basalt layers. total power up to 80 km. The lithosphere beneath the oceans has undergone many stages of partial melting as a result of the formation of oceanic crust.

33. Classification of the main anthropogenic pollutants (pollutants) of atmospheric air.

All sources of pollution are divided into point, linear and areal. In turn, point sources can be mobile and stationary (fixed). Point stationary sources of pollution include chimneys thermal power plants, heating boilers, process plants, furnaces and dryers, exhaust shafts, deflectors, ventilation pipes, etc.

Mobile sources of pollution are the exhaust pipes of diesel locomotives, motor ships, aircraft, vehicles and other moving devices.

Linear sources of air pollution are roads and streets along which vehicles systematically move.

Area sources include ventilation lanterns, windows, doors, leaks in equipment, buildings, etc., through which impurities can enter the atmosphere.

Air pollutants are called pollutants. According to the state of aggregation, emissions of harmful substances into the atmosphere can be gaseous, liquid and solid.

34. Main sources of air pollution:

The main contributors to air pollution are:

1) Thermal and nuclear power plants;

2) Ferrous metallurgy enterprises;

3) Chemical production;

4) Transport.

It is intensively polluted during the processing of raw materials, during the burning of garbage, in agricultural districts - livestock and poultry farms.

Environmental problems of the atmosphere and their brief description

The main environmental problems of the atmosphere associated with its pollution:

1) with could- poisonous mixture.

A) London smog (winter, wet)

High concentration of industrial impurities in atm air

No wind

Temperature inversion

Consequences:

Damage to the mucosa of the lungs and gastrointestinal tract

Development of chronic lung disease

Cardiovascular disease, reduced immunity

B) Los Angeles smog (dry, photochemical)

High concentration of exhaust gases in the atmosphere

A high degree of solar radiation, due to which a photochemical reaction occurred (ophtooxidants occur)

Consequences:

Damage to the mucous membrane of the lungs and gastrointestinal tract

Damage to the organs of vision

2) the greenhouse effect- an increase in the average annual temperature on the planet as a result of the accumulation of greenhouse gases in the atmosphere (carbon dioxide, methane, freons -6%), which prevent long-wave thermal radiation from the surface of the planet. (heat exchange is broken).

3) ozone "holes" - these are huge spaces (at an altitude of 20-25 km in the stratosphere) with a reduced ozone content of 50% or more.

natural factors

1) change in the cyclic activity of the sun

2) degassing - the release of deep gases through natural faults

3) the presence of layer-like ascending vortex air currents over Antarctica

Anthropogenic factors

1) the use of freons

2) shuttle launch

3) flights of supersonic aircraft at an altitude of more than 12 km

Consequences:

sunburn, cancer, disease of the organs of vision, decreased immunity

Reduced ability to photosynthesize and plants

4) acid rain - are formed as a result of industrial emissions of sulfur dioxide and nitrogen oxides into the atmosphere, which combine with atmospheric moisture to form dilute sulfuric and nitric acids.

Consequences:

Acid rain contributes to the leaching of nutrients from the soil, leads to the release of heavy metals from compounds, which reduces soil fertility and the accumulation of heavy metals in the food chain.

Features and causes of winter and summer smog

A foggy curtain over industrial enterprises and cities, formed from gaseous waste, primarily sulfur dioxide. There are winter Smog (London type) and summer Smog (Los Angeles type). Prerequisites for the formation of winter Smog are calm, calm weather, which contributes to the accumulation of vehicle exhaust gases and emissions from low chimneys. Summer smog (also called photochemical smog) is caused by nitrogen oxides and hydrocarbons, from which photooxidants, mainly ozone, are formed under intense sunlight.

Composition of the atmosphere

The Earth's atmosphere consists mainly of gases and various impurities (dust, water drops, ice crystals, sea salts, combustion products).

The concentration of gases that make up the atmosphere is almost constant, with the exception of water (H 2 O) and carbon dioxide (CO 2)

Nitrogen 75.5% Oxygen 23.10% argon 1.2% other gases (neon, helium, methane, hydrogen, etc.)

Ozone hole - a local drop in the concentration of ozone in the ozone layer of the Earth. According to the generally accepted theory in the scientific community, in the second half of the 20th century, the ever-increasing impact of anthropogenic factor in the form of release of chlorine- and bromine-containing freons led to a significant thinning of the ozone layer

It is believed that natural sources of halogens, such as volcanoes or oceans, are more significant for the process of ozone depletion than man-made ones. Without questioning the contribution of natural sources to the overall balance of halogens, it should be noted that they generally do not reach the stratosphere due to the fact that they are water-soluble (mainly chloride ions and hydrogen chloride) and are washed out of the atmosphere, falling as rain on the ground.

Consequences

The weakening of the ozone layer increases the flow of solar radiation to the earth and causes an increase in the number of skin cancers in people. Also from advanced level radiation affects plants and animals.

38.the greenhouse effect

The greenhouse effect- an increase in the temperature of the lower layers of the planet's atmosphere compared to the effective temperature, that is, the temperature of the planet's thermal radiation observed from space.

Consequences greenhouse effect 1. If the temperature on Earth continues to rise, it will have a major impact on the global climate.2. More precipitation will fall in the tropics, as the extra heat will increase the water vapor content of the air.3. In arid regions, the rains will become even more rare and they will turn into deserts, as a result of which people and animals will have to leave them.4. The temperature of the seas will also rise, which will lead to flooding of the low-lying areas of the coast and to an increase in the number of severe storms.5. Rising temperatures on Earth could cause sea levels to rise6. Residential land will be reduced.7. The water-salt balance of the oceans will be disturbed.8. The trajectories of cyclones and anticyclones will change.

Topic 1. Ecology and the natural environment.

Astronomers suggest that the Earth, along with other planets, arose about 4.6 billion years ago from one contracting gas and dust cloud, from which the Sun was formed. In accordance with modern scientific views, the Earth is represented by three layers (spheres).

The first layer is atmosphere extending into space. The modern atmosphere of the planet in composition belongs to the nitrogen-oxygen type and this qualitatively differs from the gaseous shells of all currently known celestial bodies, including planets. solar system. The atmosphere is divided into several zones: troposphere, stratosphere, mesosphere, ionosphere and exosphere.

1. Troposphere - the lower part of the atmosphere. It contains more than 80% of the total mass of air. Its height is determined by the intensity of vertical (ascending and descending) air currents caused by the heating of the earth's surface (at the equator up to a height of 16-18 km, in temperate latitudes 10-11km, at the poles up to 8 km). The troposphere is characterized by a decrease in air temperature with height, on average by 0.6 K every 100 m.

2. The stratosphere is located above the troposphere, up to a height of 50-55 km, and is characterized by an increase in temperature at its upper boundary. This is due to the presence of an ozone belt here, which intensively absorbs light radiation from the ultraviolet spectrum. At the same time, the ozone layer protects the Earth's surface from the harmful effects of this part of the solar radiation.

3. The mesosphere extends to a height of 80 km. There is a sharp decrease in temperature (down to -75-90 ° C) and the formation of silvery clouds consisting of ice crystals.

4. The ionosphere (thermosphere) reaches a height of 800 km. It is characterized by a significant increase in temperature (up to 1000°C or more). Under the direct influence of ultraviolet radiation, the gas is present here in an ionized state, which contributes to the multiple reflection of radio waves that provide long-range radio communications on Earth.

5. The exosphere is located at an altitude of 800 to 2000-3000 km and has a temperature of over 2000°C. The speed of movement of gases in it approaches the critical one (11.2 km/s). They are mainly represented by hydrogen and helium, which form a corona around the Earth, extending to a height of 20 thousand km.

The second sphere - the lithosphere - is the upper solid shell of the Earth, includes the earth's crust and upper mantle. The thickness of the lithosphere is 50-100 km, including the earth's crust - up to 75 km on the continents and 10 km under the ocean. Only top part the earth's crust (about 5% of its volume). At 47-49% it consists of oxygen, 27-28% of silicon, 8% of aluminum. They form the basis of sandy-clay minerals, the share of which in the crust reaches 80-85%. These same elements, as well as iron, calcium, sodium, potassium, magnesium and titanium, form 99.6% of the mass of the earth's crust. The remaining 105 known chemical elements account for only 0.4%. Life in the lithosphere is concentrated only in the surface layer of the earth's crust, that is, in the soil. The soil is the upper outer levels rocks, changed under the influence of water, air and the activity of living organisms, is a mixture of the remains of living organisms and inert (inorganic) substances, which has such a property as fertility. The thickness of the soil is small: from 30 cm in the tundra to 160 cm in the western chernozems.

The next layer of the Earth, about 2880 km thick, is known as the mantle. It is believed that it is mainly composed of dense silicate rocks. The third layer, about 3500 km thick, is called the core. Apparently, it consists of an outer liquid layer about 2080 km thick and a solid central part of nickel and iron at a temperature of 6400 K.

Most of the surface of our planet is occupied by the third sphere or hydrosphere including all types of reservoirs. In the most general form, the hydrosphere is divided into the World Ocean, continental and groundwater.

The bulk of the water is concentrated in the oceans. Its average depth is more than 4000 m, it covers an area equal to 71% of the earth's surface, and is characterized by high salinity. Continental water bodies cover about 5% of the Earth's area. Of these, the share of surface waters (lakes, rivers, swamps) accounts for a very small part (0.2%), glaciers - 1.7%.

In the upper part of the earth's crust there are extensive reserves of groundwater, which make up about 4% of the total volume of the hydrosphere. Fresh waters lie to a depth of 150-200 m, below they turn into brackish. Groundwater also includes ice in the permafrost.

The free waters of the hydrosphere are vertically divided into two zones. The upper zone is euphotic, determined by the depth of penetration sunlight(average 200 m). In this zone, the activity of photosynthetic organisms (plants, some bacteria) takes place. In the lower layers, where sunlight does not penetrate - the aphotic zone - live organisms that use ready-made organic substances synthesized by organisms of the euphotic zone. The entire planetary water supply reaches 1450 million km3.

The hydrosphere is closely connected with the lithosphere (groundwater), the atmosphere (water vapor) and living matter, which includes water as an essential component. It acts as a universal solvent for almost all substances, interacts with many of them. This interaction ensures the exchange of substances, for example, between land and ocean, organisms and the environment.

In addition to those named, another very peculiar shell of the Earth is distinguished, which is called biosphere, this is the area of ​​\u200b\u200bthe distribution of life on Earth, covering several geospheres inhabited by organisms: the troposphere, hydrosphere and part of the lithosphere (up to 3 km). The biosphere is a set of parts of the earth's shells, which is inhabited by living organisms, is under their influence and is occupied by the products of their vital activity.

The biosphere consists of several types of substances:

1. living matter - the totality of all living organisms on the planet (plants, animals, microorganisms);
2. biogenic substance - a substance created and processed by living organisms throughout geological history ( coal, bitumen, limestone, oil);
3. inert substance (solid, liquid, gaseous) - a substance of inorganic origin, i.e. formed in processes in which living matter does not participate;
4. bioinert substance - a substance that is created simultaneously in the processes of vital activity of living organisms and in the processes of inorganic nature, and organisms play a leading role (this includes almost all the water of the biosphere, soil, silt);
5. a substance that is in the process of radioactive decay (radioactive elements);
6. scattered atoms continuously formed from various species terrestrial matter under the influence of cosmic radiation;
7. matter of cosmic origin (cosmic dust, fragments of meteorites, etc.).

The main features of life are:

1.Unity of chemical composition. In living organisms, 98% of the chemical composition falls on 6 elements (macrobiogens): about 60% oxygen, about 20% carbon, about 10% hydrogen, 3% nitrogen, 3.5% calcium and 1% phosphorus.

2. Living systems contain set of complex biopolymers(proteins, nucleic acids, enzymes, vitamins, etc.).

3.It open systems, that is, systems that cannot exist without a constant supply of energy in the form of food, light, etc. (use external energy sources). All living systems are capable of exchanging substances with the environment, absorbing substances necessary for nutrition from it and releasing them into external environment life products.

Flows of energy and substances pass through living organisms, as a result of which metabolism is carried out in systems - metabolism(from Greek - transformation.).

Metabolism includes processes anabolism(synthesis of substances) and catabolism(decomposition of complex substances). In the processes of anabolism, under the action of enzymes, complex substances are synthesized from simpler ones with the accumulation of energy (photosynthesis).

During catabolism, the energy contained in the chemical bonds of large organic molecules is released and accumulated in the form of energy-rich phosphate bonds of adenosine triphosphoric acid (respiration, fermentation). The end products of catabolism are carbon dioxide, water, ammonia, etc. Metabolism ensures the constancy of the chemical composition of the internal environment of the body (homeostasis) and, as a result, the constancy of its functioning in continuously changing environmental conditions.

4. Living systems - highly organized and ordered systems, they are stable during life and quickly decompose after death.

5. Life on Earth manifests itself in the form discrete forms. discreteness living means that a separate organism or a community of organisms consists of separate isolated, but closely related and interacting parts, forming a structural and functional unity.

6. Living systems - self-replicating systems. The basis of self-reproduction is the formation of new molecules and structures according to the genetic program, which is embedded in the DNA of cells.

Heredity- the ability of organisms to transmit their characteristics, properties and developmental abilities from generation to generation.

7. Living systems - self-governing, self-regulating and self-organizing systems.

Self-regulation- the property of living systems to automatically set and maintain at a certain level certain indicators of the system (pH, temperature, water content, carbon dioxide, etc.), i.e. provide homeostasis.

self-organization- the property of a living system to adapt to changing environmental conditions by changing the structure of its control system. This change occurs in the process of processing information coming from the external environment, i.e. living systems with self-governing.

8. Living systems are capable of growth and development. Growth– an increase in size and mass while maintaining the general features and qualities of the system. The growth of a living system is accompanied development, that is, the emergence of new qualities and traits.

9.Historical development , that is, the irreversible and directed development of living nature, is accompanied by the formation of new species and the progressive complication of the form of life from fertilization to death. The historical development of living systems is associated with their variability.

Variability- a property opposite to heredity and associated with the acquisition by the body of new properties and characteristics under the influence of external factors as a result of self-government.

10. Living organisms are characterized rhythm, that is, periodic changes in the intensity of physiological functions with different periods of fluctuations (daily rhythms of sleep and wakefulness, seasonal rhythms of activity and hibernation of some mammals).

11. Living system - dynamic system, which actively perceives and transforms molecular information for the purpose of self-preservation.

The interaction of living organisms with the components of the biosphere (lithosphere, atmosphere, hydrosphere) occurs through exchange, nutrition, respiration and excretion of metabolic products. All organisms are not the same in terms of their accumulation of matter and energy. Plants use solar energy, carrying out the process of photosynthesis, and animals consume organic substances created by plants - photosynthetics. Therefore, all living organisms according to the method of nutrition can be divided into two classes: autotrophic And heterotrophic organisms.

autotrophic, i.e. self-feeding - they absorb the energy of the Sun and substances from the environment, create organic substances from inorganic ones. These include green plants, algae and some bacteria. According to the source of energy, autotrophs are divided into:

1.Photoautotrophs carry out the process of converting water and carbon dioxide into sugars with the release of oxygen as a by-product (photosynthesis).

2.Chemoautotrophs for the synthesis of organic substances they use chemical energy (sulfur and iron bacteria - in the oxidation of sulfur and iron compounds), they play a significant role only in groundwater ecosystems.

Heterotrophic organisms, i.e. fed by others - use ready-made organic substances as food, i.e. they feed on other animal organisms, plants or their fruits. These include herbivores, carnivores and humans.

Isolate sometimes mixotrophic organisms that, depending on environmental conditions, can combine autotrophic and heterotrophic diets. For example, aquatic unicellular organisms feed autotrophically in good light, and in the dark they switch to a heterotrophic method.

Living matter is also subdivided into:

1.Homogeneous is the biomass of organisms of the same species or genus.

2.Heterogeneous is the biomass of individuals of different species inhabiting the given ecosystem.

3.reproductive substance- living organisms, thanks to which life in the biosphere is constantly reproduced.

4.somatic substance organisms that are no longer capable of reproducing their own kind.

Living systems have a combination of the following functions:

1.Nutrition. All living systems need food as a source of energy and substances necessary for the construction of organs (the process of anabolism).

2.Breath is the process of catabolism.

3.Selection- excretion of end products of metabolism from the body.

4.Irritability- response to changes in the external and internal environment (hunger, thirst, cold). The reaction of multicellular animals to irritation is carried out with the participation of the nervous system and is called reflex.

5.reproduction.

6.Growth- unlike crystals growing from the outside, living systems grow as if from the inside, incorporating nutrients into the structure of their body.

7.Mobility- movement in the space of the entire system and movement within the system (blood in animals).

The properties of living matter include:

1. The ability to quickly master all the free space ( ubiquity of life).

2. The ability to move not only passively (under the influence of gravity), but also actively (against the flow of water, gravity, etc.).

3. Stability during life and rapid decomposition after death.

4. High adaptability (adaptation) to different conditions and, in connection with this, the development of not only all environments of life (water, air, soil), but also conditions that are difficult in terms of physicochemical parameters (temperature, radiation, etc.).

5. A very high rate of reactions, it is several orders of magnitude higher than in inanimate matter.

6. High rate of renewal of living matter (average for the biosphere is 8 years, while for land - 14 years, and for the ocean - 33 days).

In accordance with the teachings of V.I. Vernadsky, the biosphere can be divided into three sub-spheres:

1.Aerobiosphere inhabited by aerobionts, the basis of life of which is the moisture of the air. There is a layer in the aerobiosphere tropobiosphere– from the tops of the trees to the height of the most frequent location of cumulus clouds. Above the troposphere lies a layer altobiosphere where the concentration of microorganisms is very low. Above the layer of the altobiosphere there is a space where microorganisms penetrate by chance, and in this layer they do not multiply - parabiosphere.

2. In hydrobiosphere three layers are distinguished depending on the intensity of penetrating sunlight:

-photosphere– relatively brightly illuminated layer;

-dysphotosphere- Penetrates up to 1% of sunlight;

-aphtosphere- a layer of absolute darkness, where photosynthesis is impossible.

3.Geobiosphere includes:

-terrabiosphere- the area of ​​\u200b\u200blife on the surface of the earth, which is divided into phytosphere(from the surface of the Earth to the tops of the trees) and pedosphere(soils and underlying subsoils);

-lithobiosphere- life in the depths of the Earth in the pores of rocks. Life in the thickness of the lithosphere exists mainly in groundwater.

The main properties of the biosphere include:

1. The biosphere is capable accumulate solar energy and turn it into energy chemical bonds organic compounds.

2. Biosphere - complete system, it is due to the continuous exchange of matter and energy between its constituent parts.

3. Biosphere - centralized system, its center is living organisms.

4. Biosphere - open system. Its existence is impossible without a constant influx of solar energy.

5. Biosphere - self-regulating system, which is characterized by organization, the ability to maintain the initial state, i.e. after various violations, return to its original state (this property is called homeostasis).

6. The biosphere manifests rhythm- repeatability in time of certain phenomena. In nature, there are rhythms of different duration. The main ones are daily, annual, intra-secular and super-secular.

7. The biosphere has horizontal zonation and high zonation.

Horizontal zonality is a regular change in the natural environment in the direction from the equator to the poles. Zoning is due to the unequal amount of heat arriving at different latitudes due to the spherical shape of the Earth. The largest zonal divisions - geographic zones.

8. Biosphere - global multi-element system characterized by great diversity. This diversity is due to the combination of a large number of ecosystems with their characteristic species diversity.

9. The most important property of the biosphere - ensuring the circulation of substances and inexhaustibility of individual chemical elements and their compounds. Violation or, moreover, destruction of the natural cycles of chemical elements can lead to the collapse of the biosphere.

10. Biosphere - living open system. It exchanges energy and matter with the outside world. In relation to the biosphere, the outside world is space.

The biosphere includes, first of all, those areas where there are conditions for the survival and reproduction of living beings - this is field of life. They are adjacent territories in which living organisms only survive, they cannot reproduce. These areas are called life sustainability field.

The field of existence of life is determined by:

1) a sufficient amount of oxygen, carbon dioxide and water;

2) favorable temperature;

3) the subsistence minimum of minerals.

The greatest concentration of life in the biosphere is observed at the boundaries of contact between the earth's shells: atmosphere and lithosphere (land surface), atmosphere and hydrosphere (ocean surface), hydrosphere and lithosphere (ocean floor), and especially at the boundary of three shells - atmosphere, hydrosphere and lithosphere (coastal zones). These are the places where V.I. Vernadsky named films of life. Up and down from these surfaces, the concentration of living matter decreases.

There are five integral biochemical functions of the biosphere, including living matter:

1.energy function carried out mainly by plants. This function is based on the process of photosynthesis, i.e. accumulation of solar energy by green plants and its further redistribution among other components of the biosphere.

2.Environment-forming function consists in the transformation of the chemical parameters of the environment into conditions favorable for the existence of organisms. It provides the gas composition of the atmosphere, the composition of sedimentary rocks of the lithosphere and the chemical composition of the hydrosphere, the balance of substances and energy in the biosphere, and the restoration of habitats disturbed by man. The environment-forming function includes:

-Gas function provides the gas composition of the biosphere in the processes of migration and transformation of gases, most of which are of biogenic origin. Several gas functions are distinguished: oxygen-carbon dioxide (photosynthesis process), carbon dioxide (respiration process), nitrogen (nitrogen release by nitrogen-denitrophic bacteria).

-Destructive function causes the processes associated with the decomposition of dead organic matter, with the chemical destruction of rocks and the involvement of the resulting substances in the biotic cycle. As a result, bioinert and biogenic substances are formed, mineralization of organic matter occurs, i.e. its transformation into inert substance.

- Concentration function consists in the selective extraction and accumulation of biogenic elements of the environment by living organisms, causing a large difference in the composition of the living and inert matter of the planet. Thanks to this function, living organisms can serve as a source for humans, as useful substances(vitamins, amino acids), and hazardous to health (heavy metals, radioactive elements and pesticides).

-redox function living organisms is manifested in the oxidation with the participation of bacteria, fungi of all oxygen-poor compounds in the soil, weathering crust and hydrosphere. As a result of the reducing activity of anaerobic microorganisms in waterlogged soils, practically devoid of oxygen, oxidized forms of iron are formed.

3.transport function- the transfer of matter and energy as a result of the movement of living organisms. Often such a transfer is carried out over a huge distance, for example, during the flight of birds.

4.Information function. Living organisms are able to perceive, store and process molecular information and pass it on to subsequent generations.

5.Scattering function– dispersion of substances in the environment. It manifests itself through the trophic and transport activities of organisms, for example, dispersion toxic substances, dispersion of substances during excretion by organisms.

The condition for the existence and development of the biosphere is the circulation of biologically important substances. Solar energy provides two cycles of matter on Earth: geological, or large, and small, biological.

The geological cycle is clearly manifested in the example of the water cycle and atmospheric circulation. It is estimated that up to half of the energy coming from the Sun is used to evaporate water. Its evaporation from the Earth's surface is compensated by precipitation. At the same time, more water evaporates from the Ocean than returns with precipitation, and the opposite happens on land - more precipitation falls than water evaporates. Its excess flows into rivers and lakes, and from there - again into the Ocean. Along with water in the geological cycle, minerals are also transferred from one place to another.

With the advent of a living principle on the basis of a geological, or abiotic, cycle, a biological cycle arises. The biological cycle is understood as the flow of chemical elements from the soil and atmosphere into living organisms, the transformation of incoming elements into new complex compounds, followed by their return to the soil and atmosphere, as well as water.

Since the appearance of man on Earth, the formation of a new geological shell begins - noosphere(from Greek - mind), that is, the spheres of the mind. This concept was introduced by the French mathematician and philosopher E. Leroy in 1927. The noosphere is regarded as the highest stage in the development of the biosphere, associated with the emergence of a civilized society in it.

2. The concept of the scientific discipline "Ecology".

The term "ecology" (from Gr. oikos - home, homeland and logos - science) was proposed by the German biologist E. Haeckel (1866), this is the science of the relationship of the plant world, animal organisms, humans and the communities they form between themselves and the environment .

Based on the definition that ecology is a set of scientific and practical problems of the relationship between man and nature, it can be divided into general and applied ecology.

General ecology should include sections that study the anthropos impact on living matter (bioecology) and bioinert matter (geoecology) and their responses to this impact.

In bioecology, when dividing according to the level of organization of living things, one can distinguish molecular ecology, morphological ecology (cells and tissues) and autoecology, which studies living matter at the level of an individual. When divided according to the type of structuring of living things in a biological system, bioecology can be divided into the ecology of multicellular organisms (fungi, plants and animals) and unicellular organisms (microorganisms).

The subject of geoecology includes the problems of interaction in the anthropos - bioinert substance system. Taking the aggregate state of this substance as a sign of division, we obtain, for example, the division of geoecology into the ecology of land, hydrosphere and atmosphere.

The following issues should be included in the field of applied ecology: the development of common solutions, forecasts and recommendations regarding ways out of global environmental crises; development of specific managerial, legal, technological and economic solutions that improve the environmental parameters of the development of society. Based on the foregoing, applied ecology can be divided into the ecology of global crisis problems and the ecology of nature management.

The global crisis includes, for example, the problems of the greenhouse effect and the ozone layer of the Earth. The ecology of nature management is made up of industrial, agricultural, commercial, household, etc. ecology.

ENVIRONMENT AS A SYSTEM

Environment as a system - 4 hours

LECTURE No. 5-6 (4 hours).

MAN-MADE SYSTEMS AND ENVIRONMENTAL RISK

System approach in the study of ecological systems. The atmosphere, hydrosphere, lithosphere are the main components of the environment. Laws of functioning of the biosphere.

Protective mechanisms of the natural environment and factors that ensure its sustainability. Dynamic equilibrium in the environment. hydrological cycle. Cycle of energy and matter in the biosphere. Photosynthesis.

Conditions and factors that ensure safe life in the environment. Natural "nourishing" cycles, mechanisms of self-regulation, self-purification of the biosphere. Renewable and non-renewable natural resources.

The totality of all biogeocenoses (ecosystems) of our planet creates a giant global ecosystem called the biosphere (from the Greek bios - life, sphere - ball) - the area of ​​​​systemic interaction between the living and bone matter of the planet. The biosphere is the entire space where life exists or has ever existed, i.e. where living organisms or their metabolic products are found. That part of the biosphere where living organisms are currently found is called the modern biosphere, or neobiosphere, and the ancient biospheres are referred to as former biospheres, otherwise paleobiospheres or megaspheres. Examples of the latter are lifeless accumulations of organic matter (deposits of coal, oil, gas, etc.) or reserves of other compounds formed with the direct participation of living organisms (limestones, shell rocks, chalk formations, a number of ores, and many others).

The biosphere includes: the aerobiosphere (the lower part of the atmosphere), the hydrobiosphere (the entire hydrosphere), the lithobiosphere (the upper horizons of the lithosphere - the solid earth's shell). The boundaries of the neo- and paleobiosphere are different. Theoretically, their upper limit is determined by the ozone layer. For the neobiosphere, this is the lower boundary of the ozone layer (about 20 km), which attenuates harmful cosmic ultraviolet radiation to an acceptable level, and for the paleobiosphere, this is the upper boundary of the same layer (about 60 km), because oxygen in the Earth’s atmosphere is the result of mainly the vital activity of vegetation (so the same as other gases to an appropriate extent).

The biosphere is a part of the shells of the globe inhabited by living organisms, i.e. part of the atmosphere, hydrosphere and lithosphere.

16) Characteristics of the chemical composition of the atmosphere as a geosphere and part of the biosphere

The Earth's atmosphere is the gaseous shell that surrounds the Earth. The atmosphere is called that area around the Earth in which the gaseous medium rotates with it as a whole. The mass of the atmosphere is 5.15 - 5.9x10 15 tons. The atmosphere as a component of biogeocenosis is a layer of air in the soil and above its surface, within which the interaction of the components of the biosphere is observed.

The modern atmosphere is of secondary origin and was formed from gases released by the solid shell of the Earth after the formation of the planet. During the geological history of the Earth, the atmosphere has undergone a significant evolution under the influence of a number of factors: the escape of atmospheric gases into outer space;

gas emissions as a result of volcanic activity, splitting of molecules under the influence of solar ultraviolet radiation, chemical reactions between the components of the atmosphere and rocks of the earth's crust; capturing the interplanetary medium.

The development of the atmosphere is closely connected with geological and geochemical processes, as well as with the activities of living organisms. The atmosphere protects the Earth's surface from the damaging effects of falling meteorites, most of which burn up in the dense layers of the atmosphere.

In terms of its structure, the atmosphere has a complex structure, which is determined by the features of the vertical temperature distribution. At altitudes of more than 1000 km, there is an exosphere, from where atmospheric gases are dispersed into the world space. Here there is a gradual transition from the atmosphere to interplanetary space. All structural parameters of the atmosphere - temperature, pressure and density - have a significant spatio-temporal variability.

The complex structure of the atmosphere is also manifested in its chemical composition. So, if at altitudes up to 90 km, where there is intense mixing, the relative gas composition remains practically unchanged, then above 90 km, under the influence of ultraviolet radiation from the sun, dissociation of gas molecules occurs and a strong change in the composition of the atmosphere with height. Typical features of this part of the atmosphere are the ozone layer and its own glow. A complex layered structure is characteristic of atmospheric aerosol - liquid or solid particles of terrestrial or cosmic origin suspended in a gaseous medium. Aerosol with liquid particles - fog, with solid particles - smoke. The diameter of solid aerosol particles is on average 10 -9 - 10 -13 mm, droplets 10 -6 - 10 -2 mm. The vertical distribution of electrons and ions in the atmosphere is also layered, which is expressed in the existence of different layers of the ionosphere.

The composition of the Earth's atmosphere is unique. For example, if the atmospheres of Jupiter and Saturn consist mainly of hydrogen and helium. Mars and Venus - from carbon dioxide, the Earth's atmosphere consists mainly of oxygen and nitrogen. It also contains argon, carbon dioxide, neon and other constant and variable components. The volume concentration of nitrogen is 78.084%, oxygen - 20.9476%, argon - 0.934%, carbon dioxide - 0.0314. These data refer only to the lower layers of the atmosphere.

The most important variable component of the atmosphere is water vapour. The spatial and temporal variability of its concentration varies widely near the earth's surface - from 3% in the tropics to 0.00002% in Antarctica. The bulk of water vapor is concentrated in the troposphere, and its concentration rapidly decreases with height. The average content of water vapor in the vertical column of the atmosphere in temperate latitudes is about 15-17 mm of the "precipitated water layer".

Ozone has a significant impact on atmospheric processes, especially the thermal regime. It is mainly concentrated in the stratosphere, where it causes the absorption of ultraviolet solar radiation. The average monthly values ​​of the total ozone content vary depending on the latitude and season and make up the layer thickness in the range of 2.3-5.2 mm at terrestrial pressure and temperature values. There is an increase in the ozone content from the equator to the poles and annual changes with a minimum in autumn and a maximum in spring. At present, the destruction of the ozone layer under the influence of economic activity has been noted. The main destroyers of the ozone layer are freons (freons), which are a group of halogen-containing substances, freons are inert at the Earth's surface, but, rising into the stratosphere, they undergo photochemical decomposition, emit a chlorine ion, which serves as a catalyst for chemical reactions that destroy ozone molecules.

The outer, upper boundary of the atmosphere gradually turns into interplanetary gas, the density of which is 1000 pairs of ions per cubic centimeter.

17) Characteristics of the chemical composition of the hydrosphere how geosphere and parts of the biosphere

The hydrosphere is the water shell of the Earth. Due to the high mobility of water, they penetrate everywhere into various natural formations. Water is in the form of vapors and clouds in the earth's atmosphere, forms oceans and seas, exists in the form of glaciers in the highlands of the continents. Atmospheric precipitation penetrates into the strata of sedimentary rocks, forming groundwater. Water is capable of dissolving many substances, so any water of the hydrosphere can be considered as natural solutions of varying degrees of concentration. Even the purest atmospheric waters contain 10-50 mg/l of dissolved substances.

Water as hydrogen oxide H2O is the simplest stable combination of hydrogen and oxygen under normal conditions. The total amount of water on the planet is approximately 1.5-2.5x10 24 grams (from 1-5 to 2.5 billion km3).

According to V.I. Vernadsky, water stands apart in the history of our planet, but water plays an important role in the geological history of the Earth. Water is one of the factors in the formation of physical and chemical environment, climate and weather on our planet, the emergence of life on Earth.

Our planet is 3/4 covered with water, ice; clouds float above it in the form of accumulations of vaporous water. Water fills the cells of plants, animals; The cells of the human body are on average 70% water.

Waters in natural conditions always contain dissolved salts, gases, organic substances. Their concentration varies depending on the origin of water and environmental conditions. At a salt concentration of up to 1 g / kg, water is considered fresh, up to 25 g / kg - brackish and more than 25 g / kg - salty.

Atmospheric precipitation is considered the least mineralized, in which, on average, the salt concentration is 10-20 mg/kg, then fresh lakes and rivers (5-1000 mg/kg). The salinity of the ocean is about 35 g/kg. The seas have a lower mineralization - from 8 to 22 g/kg. Mineralization of groundwater near the surface in conditions of excessive moisture is up to 1 g/kg, and in arid conditions up to 100 g/kg.

In fresh waters, HCO3 - (-), Ca 2+, Mg 2+ ions usually predominate. As the total mineralization increases, the concentration of SO4 - , Cl - , Na + , K + ions increases. In highly mineralized waters, chloride and sodium ions predominate, less often magnesium and very rarely calcium ions. Other elements are contained in very small quantities, but almost all natural elements of the periodic table are found in natural waters.

Of the dissolved gases in water, nitrogen, oxygen, carbon dioxide, noble gases, and rarely hydrogen sulfide and hydrocarbons are present.

The concentration of organic matter is low. It is: in rivers - about 20 mg / l, in groundwater even less and in the oceans - about 4 mg / l. The exceptions are swamp waters and waters of oil fields, as well as waters. Contaminated by industrial and domestic effluents, where the concentration of organic matter can be high.

The primary sources of salts in natural waters are substances that are formed during the chemical weathering of igneous rocks, as well as substances that have been released from the bowels of the Earth throughout its history. The composition of water depends on the diversity of the composition of these substances and the conditions under which they interacted with water. Of great importance for the formation of the composition of water is the impact on it of living organisms, as well as economic activity person.

The role of the World Ocean in stabilizing natural conditions on the Earth's surface is enormous. This is largely due to its weight and area.

About 52.6% of the ocean water area has a depth of 4000 to 6000 m. Areas with depths of more than 6000 m occupy about 1.2%, shallow areas - up to 200 m - also occupy small area- 7.5%. The rest of the water area, about 38.7%, has a depth of 200 to 4000 m. Most of the World Ocean is located in the southern hemisphere, where it occupies 81% of the surface area, in the northern hemisphere - 61% of the surface.

In general, the hydrosphere is identified with the oceans and seas, since their mass makes up 91.3% of the entire hydrosphere.

Water is the most powerful absorber of solar heat energy on the Earth's surface. The decisive role in the absorption of solar energy on our planet belongs to the World Ocean, whose ability to absorb solar energy is 2-3 times greater than that of the land surface. Only 8% of solar radiation is reflected from the ocean surface. The ocean is the heat sink on the planet. Its heating occurs in the equatorial belt approximately in the band from 15 degrees South latitude to 30 degrees North latitude. At higher latitudes in both hemispheres, the ocean releases heat received in the heating belt.

The waters of the World Oksan are in active motion all the time. This is facilitated by atmospheric circulation, uneven heating of the surface, salinity contrasts, temperature contrasts, and the forces of attraction of the Moon and the Sun.

However, due to its diversity, the hydrosphere is extremely resistant to external and internal influences. A significant variety is created by the simultaneous existence of water in three phases, which differ sharply in their components, a large set of substances and gases dissolved in it, and the formation of various static and dynamic structures. The Earth's hydrosphere as a component of the biosphere is a global thermodynamic open system that is stable and maintains the stability of the biosphere as a whole.

18) Characteristics of the chemical composition of the lithosphere as a geosphere and part of the biosphere

The Earth's crust is the most heterogeneous shell of the Earth, formed by various mineral associations in the form of sedimentary, igneous and metamorphic rocks of various occurrence forms.

At present, the earth's crust is understood as the upper layer of the solid body of the planet, located above the seismic boundary. This boundary is located at different depths, where there is a sharp jump in the speed of seismic waves that occur during an earthquake. There are two types of the earth's crust - continental and oceanic. Continental is characterized by a deeper seismic boundary. At present, the term lithosphere, proposed by E. Suess, is more often used, which is understood as a region that is more extensive than the earth's crust.

The lithosphere is the upper solid shell of the Earth, which has greater strength and turns into a less durable asthenosphere. The lithosphere includes the earth's crust and upper mantle to a depth of approximately 200 km.

The structure of the earth's crust is uneven. Mountain systems alternate with plains on the continents. Continents, in turn, are areas of the earth's crust elevated above sea level. Spatial arrangement of continents on the planet V.I. Vernadsky called it "dissymmetry of the planet". If we divide the globe along the Pacific coast into two halves, then we get, as it were, two hemispheres: continental, where all the continents are concentrated with the Atlantic and Indian Oceans, and oceanic, which will occupy the area of ​​the entire Pacific Ocean. This is due to the structure and composition of the earth's crust within the continental and oceanic hemispheres. The different thickness of the earth's crust in the area of ​​continents and oceans is associated with a difference in the composition of the rocks that make it up. The oceanic crust is composed mainly of basalt material, while the continental crust is composed of material similar in composition to granite. Granite rocks contain more silicic acid and less iron than basalt.

The general chemical composition of the earth's crust is determined by a few chemical elements. Only eight elements: oxygen, silicon, aluminum, iron, calcium, sodium, magnesium, potassium are distributed in the earth's crust in a weight amount of more than 1%. The leading, most common element of the earth's crust is oxygen, which makes up almost half of the mass (47.3%) and 92% of its volume. Thus, quantitatively, the earth's crust is the realm of oxygen chemically bound to other elements.

The abundance of chemical elements in the earth's crust is not the same and repeats to a certain extent the cosmic abundance. The light elements of the four serial numbers that make up the first four periods of the periodic table predominate. The predominance of oxygen among the chemical elements of the earth's crust determines the leading importance of the distribution of minerals, of which it is a part. Using data on the abundance of elements in the earth's crust, it is possible to calculate the ratio of its constituent minerals, usually called rock-forming.

The surface of the continents is 80% occupied by sedimentary rocks, and the ocean floor - almost completely by fresh sediments as products of the demolition of the material of the continents and the activity of marine organisms. The earth's crust originally arose as a product of the melting of the primary mantle, which was then processed in the biosphere under the influence of air, water, and the activity of living organisms.

The continental part of the earth's crust during a long geological history was in the biosphere, which left its mark on the appearance, composition and prevalence of sedimentary rocks and the concentration of minerals in them in the form of coal, oil, oil shale, siliceous and carbonaceous rocks, associated in the past with the vital activity of organisms. In this regard, the continental crust is directly related to the Earth's biosphere.

19) Laws of functioning of the biosphere.

main role in the theory of the biosphere V.I. Vernadsky plays the idea of ​​living matter and its functions.

The main function of the biosphere is to ensure the circulation of chemical elements. The global biotic cycle is carried out with the participation of all organisms inhabiting the planet. It consists in the circulation of substances between the soil, atmosphere, hydrosphere and living organisms. Thanks to the biotic cycle, a long existence and development of life is possible with a limited supply of available chemical elements. Using inorganic substances, green plants, using the energy of the sun, create organic matter, which is destroyed by other living beings (consumer heterotrophs and destructors) so that the products of this destruction can be used by plants for new organic syntheses.

Another important function of living matter, and, consequently, the biosphere is gas function. Thanks to the activity of living matter, the composition of the atmosphere has changed, in particular, as a result of the process of photosynthesis, significant amounts of oxygen appeared in it. Most of the gases in the upper horizons of the planet are generated by life. IN upper layers troposphere and in the stratosphere, under the influence of ultraviolet radiation, ozone is formed from oxygen. The existence of the ozone screen is also the result of the activity of living matter, which, according to V.I. Vernadsky, "as if it creates for itself the area of ​​life." Carbon dioxide enters the atmosphere as a result of the respiration of all living organisms. All atmospheric nitrogen is of organogenic origin. The gases of organic origin also include hydrogen sulfide, methane and many other volatile compounds resulting from the decomposition of organic matter of plant origin, previously buried in sedimentary strata.

Living matter is capable of redistributing atoms in the biosphere. One of the functions of living matter is concentration. Many organisms have the ability to accumulate certain elements in themselves, despite their insignificant content in the environment. Carbon comes first. Many organisms concentrate calcium, silicon, sodium, aluminum, iodine, etc. When they die, they form an accumulation of these substances. There are deposits of coal, limestone, bauxite, phosphorite, sedimentary iron ores, etc. Many of them are used by man as minerals.

The redox function of living matter lies in its ability to carry out oxidative and reduction chemical reactions that are almost impossible in inanimate nature. In the biosphere, as a result of the vital activity of microorganisms, such chemical processes as the oxidation and reduction of elements with variable valence (nitrogen, sulfur, iron, manganese, etc.) are carried out on a large scale. Microorganisms-restorers - heterotrophs - use organic substances as an energy source. These include denitrifying and sulfate-reducing bacteria that reduce nitrogen from oxidized forms to the elemental state and sulfur to hydrogen sulfide. Microorganisms-oxidizers can be both autotrophs and heterotrophs. These are bacteria that oxidize hydrogen sulfide and sulfur, nitri- and nitrifying microorganisms, iron and manganese bacteria that concentrate these metals in their cells.

20) Protective mechanisms of the natural environment and factors that ensure its sustainability. Dynamic equilibrium in the environment. hydrological cycle. Cycle of energy and matter in the biosphere. Photosynthesis.

The biosphere acts as a huge, extremely complex ecological system operating in a stationary mode on the basis of fine regulation of all its constituent parts and processes.

The stability of the biosphere is based on a high diversity of living organisms, individual groups of which perform different functions in maintaining the overall flow of matter and energy distribution, on the closest interweaving and interconnection of biogenic and abiogenic processes, on the consistency of the cycles of individual elements and balancing the capacity of individual reservoirs. Complex systems of feedbacks and dependencies operate in the biosphere.

The stability of the biosphere is due to the fact that the results of the activity of three groups of organisms that perform different functions in the biotic cycle - producers (autotrophs), consumers (heterotrophs) and decomposers (mineralizing organic residues) - are mutually balanced.

Important for maintaining the stability of the biosphere, along with the biological cycle, is the water cycle, the source of energy for which is solar radiation. Living organisms play a huge role in the water cycle, in particular, transpiring plants, the creation of a unit of production of which requires hundreds of times more transpired moisture.

Within limited areas, the water cycle consists in its evaporation from the surface of the soil, water bodies, plants, the concentration of clouds and precipitation. Within the limits of the entire planet, this cycle is expressed in the water exchange "oceans - continents". Water evaporated from the surface of the ocean is carried by winds to the continents, falls over them, and returns to the ocean with river and underground runoff.

The water cycle is the main source of mechanical work in the biosphere, while the biological cycle is mainly due to chemical processes, which are accompanied by the transformation of chemical energy. but mechanical work performed on Earth during the water cycle - weathering, dissolution, etc. - nevertheless, it is committed either with the participation of living organisms or at the expense of their metabolic products. The movement of water is carried out in the biosphere by the processes of erosion, transport, redistribution, sedimentation and accumulation of mechanical and chemical precipitation on land and in the ocean.

Solar energy causes planetary movements of air masses as a result of their uneven heating. Grandiose processes of atmospheric circulation arise, which are of a rhythmic nature.

All these planetary processes on Earth are closely intertwined, forming a common, global cycle of substances that redistributes the energy coming from the sun. It is carried out through a system of small cycles. Tectonic processes are connected to large and small cycles, due to volcanic activity and the movement of oceanic plates in the earth's crust. As a result, a large geological circulation of substances is carried out on Earth.

Any biological cycle is characterized by the repeated inclusion of atoms of chemical elements in the bodies of living organisms and their release into the environment, from where they are again captured by plants and involved in the cycle. A small biological cycle is characterized by capacity - the number of chemical elements that are simultaneously in the composition of living matter in a given ecosystem, and speed - the amount of living matter formed and decomposed per unit time.

The speed of biological cycles on land is years and decades, in aquatic ecosystems - a few days or weeks.

The biological circulation of the land and hydrosphere unite the cycles of individual landscapes through water runoff and atmospheric movements. Particularly important is the role of the circulation of water and the atmosphere in uniting all the continents and oceans into a single cycle of the biosphere.

A large geological cycle involves sedimentary rocks deep into the earth's crust, for a long time turning off the elements contained in them from the system of biological circulation. In the course of geological history, the transformed sedimentary rocks, once again on the surface of the Earth, are gradually destroyed by the activity of living organisms, water and air, and are again included in the biospheric cycle.

It has been established that in the last 600 million years the nature of the main cycles on the Earth has not changed significantly. Fundamental geochemical processes were carried out, which are also characteristic of the modern era: oxygen accumulation, nitrogen fixation, calcium precipitation, the formation of siliceous shales, the deposition of iron, manganese ores and sulfide minerals, and the accumulation of phosphorus. Only the speed of these processes changed. In general terms, the total flow of atoms involved in living organisms did not change either. Experts believe that the mass of living matter has remained approximately constant since the Carboniferous period, i.e., the biosphere has since maintained itself in a certain stable regime of cycles.

The stable state of the biosphere is due to the activity of the living matter itself, which provides a certain degree of fixation of solar energy (photosynthesis) and the level of biogenic migration of atoms.

For example, the carbon cycle begins with the fixation of atmospheric carbon dioxide through photosynthesis. Part of the carbohydrates formed in the process of photosynthesis is used by the plants themselves for energy, the other part is consumed by animals. Carbon dioxide is released during the respiration of plants and animals. Dead plants and animals decompose, the carbon in their tissues is oxidized and returned to the atmosphere. A similar process occurs in the ocean.

It must be taken into account that the stability of the biosphere, like any other system, has certain limits.

Human society, using not only the energy resources of the biosphere, but also non-biospheric sources of energy (for example, nuclear), accelerates geochemical transformations on the planet, interferes with the course of biospheric processes. Some processes caused by human activities have an opposite direction to natural processes (dispersion of metal ores, carbon and other biogenic elements, inhibition of mineralization and humification, release of carbon and its oxidation, disruption of global processes in the atmosphere that affect climate, etc.). d.).

Accordingly, one of the main tasks modern ecology is the study of regulatory processes in the biosphere, the creation of a scientific foundation for its rational use, maintaining its stability.

21) Conditions and factors that ensure safe life in the environment. Natural "nourishing" cycles, mechanisms of self-regulation, self-purification of the biosphere. Renewable and non-renewable natural resources.

Maintaining the vital activity of organisms and the circulation of substances in ecosystems is possible only due to a constant influx of energy. More than 99% of the energy reaching the Earth's surface is solar radiation. This energy is wasted in large quantities on physical and chemical processes in the atmosphere, hydrosphere and lithosphere: mixing of air flows and water masses, evaporation, redistribution of substances, dissolution of minerals, absorption and release of gases.

Only 1/2,000,000 of the solar energy reaches the Earth's surface, while 1-2% of it is assimilated by plants. There is only one process on Earth in which the energy of solar radiation is not only spent and redistributed, but also bound, stored for a very long time. This process is the creation of organic matter during photosynthesis. By burning coal in furnaces, we release and use solar energy stored by plants hundreds of millions of years ago.

The main planetary function of plants (autotrophs) is to bind and store solar energy, which is then spent on maintaining biochemical processes in the biosphere.

Heterotrophs get energy from food. All living beings are objects of nourishment for others, i.e. connected with each other by energy relations. Food connections in biocenoses are a mechanism for transferring energy from one organism to another. Organisms of any species are a potential source of energy for another species. In each community, trophic relationships form a complex network. However, the energy that enters the food web cannot migrate in it for a long time. It can be transmitted through no more than 4-5 links, because There are energy losses in power circuits. The location of each link in the food chain is called a trophic level.

The first trophic level is producers, creators of plant biomass; herbivorous animals (consumers of the 1st order) belong to the second trophic level; carnivorous animals living at the expense of herbivorous forms are consumers of the 2nd order; carnivores that eat other carnivores - consumers of the 3rd order, etc.

The energy balance of consumers is formed as follows. Ingested food is usually not fully digested. The percentage of digestibility depends on the composition of the food and the presence of digestive enzymes in the body. In animals, from 12 to 75% of food is assimilated in the process of metabolism. The undigested part of the food is again returned to the external environment (in the form of excrement) and may be involved in other food chains. Most of the energy received as a result of the breakdown of nutrients is spent on physiological processes in the body, a smaller part is transformed into the tissues of the body itself, i.e. spent on growth, weight gain, deposition of reserve nutrients.

The transfer of energy in chemical reactions in the body occurs, according to the second law of thermodynamics, with the loss of part of it in the form of heat. These losses are especially great during the work of muscle cells of animals, the efficiency of which is very low.

Expenses for breathing are also many times greater than the energy costs for increasing body weight. Specific ratios depend on the stage of development and the physiological state of individuals. Young individuals spend more on growth, while mature individuals use energy almost exclusively to maintain metabolism and physiological processes.

Thus, most of the energy in the transition from one link of the food chain to another is lost, because. used by another, next link, perhaps only the energy contained in the biomass of the previous link. It is estimated that these losses are about 90%; only 10% of the consumed energy is stored in biomass.

In accordance with this, the energy reserve accumulated in plant biomass in food chains is rapidly depleting. Lost energy can be replenished only at the expense of the energy of the Sun. In this regard, in the biosphere there cannot be an energy cycle similar to the cycle of substances. The biosphere functions only due to the unidirectional flow of energy, its constant input from the outside in the form of solar radiation,

Food chains that start with photosynthetic organisms are called consumption chains, and chains that start with dead plant remains, carcasses and animal excrement are called detrital decomposition chains.

Thus, the energy flow in the biosphere is divided into two main channels, reaching consumers through living plant tissues or dead organic matter, the source of which is also photosynthesis.

Planet Earth consists of the lithosphere (solid body), atmosphere ( air envelope), hydrosphere (water shell) and biosphere (the sphere of distribution of living organisms). There is a close relationship between these spheres of the Earth, due to the circulation of substances and energy.

Lithosphere. The Earth is a ball, or spheroid, somewhat flattened at the poles, with a circumference around the equator of about 40,000 km.

In the structure of the globe, the following shells, or geospheres, are distinguished: the lithosphere proper (outer stone shell) with a thickness of about 50 ... 120 km, the mantle extending to a depth of 2900 km and the core - from 2900 to 3680 km.

According to the most common chemical elements that make up the Earth's shell, it is divided into the upper - siallitic, which extends to a depth of 60 km and has a density of 2.8 ... having a density of 3.0...3.5 g/cm 3 . The names "siallitic" (sial) and "simatic" (sima) shells come from the designations of the elements Si (silicon), Al (aluminum) and Mg (magnesium).

At a depth of 1200 to 2900 km there is an intermediate sphere having a density of 4.0...6.0 g/cm 3 . This shell is called "ore", as it contains a large amount of iron and other heavy metals.

Deeper than 2900 km is the core of the globe with a radius of about 3500 km. The core consists mainly of nickel and iron and has a high density (10...12 g/cm3).

According to the physical properties of the earth's crust is heterogeneous, it is divided into continental and oceanic types. The average thickness of the continental crust is 35...45 km, the maximum thickness is up to 75 km (under mountain ranges). Sedimentary rocks up to 15 km thick lie in its upper part. These rocks were formed over long geological periods as a result of the change of seas by land, climate change. Under the sedimentary rocks there is a granite layer with an average thickness of 20...40 km. The thickness of this layer is greatest in the areas of young mountains, it decreases towards the periphery of the mainland, and there is no granite layer under the oceans. Under the granite layer there is a basalt layer with a thickness of 15 ... 35 km, it is composed of basalts and similar rocks.

The oceanic crust is less thick than the continental crust (from 5 to 15 km). The upper layers (2...5 km) consist of sedimentary rocks, and the lower (5...10 km) - of basalt.

Sedimentary rocks located on the surface of the earth's crust serve as the material basis for soil formation; igneous and metamorphic rocks take a small part in the formation of soils.

The main mass of rocks is formed by oxygen, silicon and aluminum (84.05%). If five more elements are added to these three elements - iron, calcium, sodium, potassium and magnesium, then in total they will amount to 98.87% of the rock mass. The remaining 88 elements account for slightly more than 1% of the mass of the lithosphere. However, despite the low content of micro- and ultramicroelements in rocks and soils, many of them have great importance for the normal growth and development of all organisms. At present, much attention is paid to the content of microelements in the soil, both in connection with their importance in plant nutrition, and in connection with the problems of protecting soils from chemical pollution. The composition of elements in soils mainly depends on their composition in rocks. However, the content of some elements in rocks and soils formed on them varies somewhat. This is connected both with the concentration of nutrients and with the course of the soil-forming process, during which a relative decrease in a number of bases and silica occurs. Thus, soils contain more oxygen than the lithosphere (respectively 55 and 47%), hydrogen (5 and 0.15%), carbon (5 and 0.1%), nitrogen (0.1 and 0.023%).

Atmosphere. The boundary of the atmosphere passes where the force of the earth's gravity is compensated by the centrifugal force of inertia due to the rotation of the Earth. Above the poles, it is located at an altitude of about 28 thousand km, and above the equator - 42 thousand km.

The atmosphere consists of a mixture of various gases: nitrogen (78.08%), oxygen (20.95%), argon (0.93%) and carbon dioxide (0.03% by volume). The composition of the air also includes a small amount of helium, neon, xenon, krypton, hydrogen, ozone, etc., which in total make up about 0.01%. In addition, the air contains water vapor and some dust.

The atmosphere consists of five main shells: troposphere, stratosphere, mesosphere, ionosphere, exosphere.

Troposphere- the lower layer of the atmosphere, has a thickness above the poles of 8 ... 10 km, in temperate latitudes - 10 ... 12 km, and in equatorial latitudes - 16 ... 18 km. About 80% of the mass of the atmosphere is concentrated in the troposphere. Almost all of the water vapor in the atmosphere is located here, precipitation is formed and air moves horizontally and vertically.

Stratosphere extends from 8...16 to 40...45 km. It includes about 20% of the atmosphere, water vapor is almost absent in it. There is a layer of ozone in the stratosphere that absorbs ultraviolet radiation from the sun and protects living organisms on Earth from death.

Mesosphere extends at an altitude of 40 to 80 km. The density of air in this layer is 200 times less than that of the earth's surface.

Ionosphere located at an altitude of 80 km and consists mainly of charged (ionized) oxygen atoms, charged nitric oxide molecules and free electrons.

Exosphere represents the outer layers of the atmosphere and starts from a height of 800 ... 1000 km from the Earth's surface. These layers are also called the scattering sphere, since here gas particles move with high speed and can escape into outer space.

Atmosphere It is one of the indispensable factors of life on Earth. Sun rays, passing through the atmosphere, are scattered, and also partially absorbed and reflected. Water vapor and carbon dioxide absorb heat rays especially strongly. Under the action of solar energy, the movement of air masses occurs, the climate is formed. Precipitation falling from the atmosphere is a factor in soil formation and a source of life for plant and animal organisms. The carbon dioxide contained in the atmosphere in the process of photosynthesis of green plants turns into organic matter, and oxygen serves for the respiration of organisms and the oxidative processes occurring in them. The importance of atmospheric nitrogen, which is captured by nitrogen-fixing microorganisms, serves as an element of plant nutrition and participates in the formation of protein substances.

Under the action of atmospheric air, weathering of rocks and minerals and soil-forming processes occur.

Hydrosphere. Most of the surface of the globe is occupied by the World Ocean, which, together with lakes, rivers and other bodies of water located on the earth's surface, occupies 5/8 of its area. All the waters of the Earth, located in the oceans, seas, rivers, lakes, swamps, as well as groundwater, constitute the hydrosphere. Of the 510 million km 2 of the Earth's surface, 361 million km 2 (71%) falls on the World Ocean and only 149 million km 2 (29%) is on land.

The surface waters of the land, together with the glacial waters, make up about 25 million km 3, that is, 55 times less than the volume of the World Ocean. About 280 thousand km 3 of water are concentrated in the lakes, about half of them are fresh lakes, and the second half are lakes with waters of varying degrees of salinity. The rivers contain only 1.2 thousand km 3, that is, less than 0.0001% of the total water supply.

The waters of open reservoirs are in constant circulation, which connects all parts of the hydrosphere with the lithosphere, atmosphere and biosphere.

Atmospheric moisture is actively involved in water exchange, with a volume of 14 thousand km 3 it forms 525 thousand km 3 of precipitation falling on the Earth, and the change of the entire volume of atmospheric moisture occurs every 10 days, or 36 times during the year.

Evaporation of water and condensation of atmospheric moisture provide fresh water on Earth. About 453 thousand km 3 of water evaporates annually from the surface of the oceans.

Without water, our planet would be a bare stone ball, devoid of soil and vegetation. For millions of years, water has destroyed rocks, turning them into junk, and with the advent of vegetation and animals, it has contributed to the process of soil formation.

Biosphere. The composition of the biosphere includes the land surface, the lower layers of the atmosphere and the entire hydrosphere, in which living organisms are common. According to the teachings of V. I. Vernadsky, the biosphere is understood as the shell of the Earth, the composition, structure and energy of which are determined by the activity of living organisms. V. I. Vernadsky pointed out that “there is no chemical force on the earth’s surface that is more constantly acting, therefore more powerful than living organisms taken as a whole.” Life in the biosphere develops in the form of an exceptional variety of organisms inhabiting the soil, the lower layers of the atmosphere and the hydrosphere. Thanks to the photosynthesis of green plants, solar energy is accumulated in the biosphere in the form of organic compounds. The whole set of living organisms ensures the migration of chemical elements in soils, in the atmosphere and hydrosphere. Under the action of living organisms, gas exchange, oxidative and reduction reactions occur in soils. The origin of the atmosphere as a whole is connected with the gas exchange function of organisms. In the process of photosynthesis in the atmosphere, the formation and accumulation of free oxygen occurred.

Under the influence of the activity of organisms, weathering of rocks and the development of soil-forming processes are carried out. Soil bacteria are involved in the processes of desulfification and denitrification with the formation of hydrogen sulfide, sulfur compounds, N(II) oxide, methane, and hydrogen. The construction of plant tissues occurs due to the selective absorption of biogenic elements by plants. After the plants die, these elements accumulate in the upper soil horizons.

In the biosphere, two cycles of substances and energy, opposite in their direction, take place.

A large, or geological, cycle occurs under the influence of solar energy. The water cycle involves the chemical elements of the land, which enter the rivers, seas and oceans, where they are deposited along with sedimentary rocks. This is an irretrievable loss from the soil of the most important plant nutrients (nitrogen, phosphorus, potassium, calcium, magnesium, sulfur), as well as trace elements.

A small, or biological, cycle takes place in the system soil - plants - soil, while plant nutrients are removed from the geological cycle and stored in humus. At biological cycle there are cycles associated with oxygen, carbon, nitrogen, phosphorus and hydrogen, which continuously circulate in plants and the environment. Some of them are withdrawn from the biological cycle and, under the influence of geochemical processes, pass into sedimentary rocks or are transferred to the ocean. The task of agriculture is to create such agrotechnical systems in which biogenic elements would not enter the geological cycle, but would be fixed in the biological cycle, maintaining soil fertility.

The biosphere consists of biocenoses, which are a homogeneous territory with the same type of plant community along with the animal world inhabiting it, including microorganisms. Biogeocenosis is characterized by soils peculiar to it, water regime, microclimate and topography. Natural biogeocenosis is relatively stable, it is characterized by self-regulating ability. The species included in the biogeocenosis adapt to each other and the environment. This is a complex relatively stable mechanism capable of resisting changes in the environment through self-regulation. If changes in biogeocenoses exceed their self-regulating ability, then irreversible degradation of this ecological system may occur.

Agricultural lands are artificially organized biogeocenoses (agrobiocenoses). The effective and rational use of agrobiocenoses, their sustainability and productivity depend on the proper organization of the territory, the farming system and other socio-economic activities. To ensure optimal impact on soils and plants, it is necessary to know all the relationships in the biogeocenosis and not disturb the ecological balance that has developed in it.