In South America, there are many environmental problems caused by technological progress and economic development. Forests are being destroyed and water bodies polluted, biodiversity is diminishing and soil is depleted, the atmosphere is being polluted and wildlife habitats are diminishing. All this can lead to an environmental disaster in the future.
In the cities of South American countries, environmental problems of the following nature have formed:

• the problem of unsanitary conditions;
• water pollution;
• the problem of garbage and solid waste disposal;
• air pollution;
• the problem of energy resources, etc.

Deforestation problem

Much of the mainland is covered by tropical forests, which are the lungs of the planet. Trees are constantly cut down not only to sell timber, but also to create agricultural land and pastures. All this leads to a change in the forest ecosystem, the destruction of some species of flora and the migration of fauna. In order to preserve the forest, many countries regulate logging activities at the legislative level. There are whole zones where it is prohibited, reforestation and new trees are being planted.

Hydrosphere problems

In the coastal areas of the seas and oceans, there are many problems:

• overfishing;
• pollution of water with garbage, oil products and chemicals;
• housing and communal and industrial effluents.

All these wastes negatively affect the state of water bodies, flora and fauna.

In addition, many rivers flow along the mainland, including the largest river in the world - the Amazon. The rivers of South America are also affected by human activity. Many species of fish and animals disappear in the waters. The life of local tribes, who have lived on the banks of rivers for thousands of years, has also become very complicated, they are forced to look for new habitats for themselves. Dams and various structures have led to changes in river regimes and water pollution.

Biosphere pollution

The source of air pollution is the greenhouse gases emitted by vehicles and industrial plants:

• mines and deposits;
• chemical industry enterprises;
• oil refineries;
• energy facilities;
• metallurgical plants.

Agriculture, which uses pesticides, chemical and mineral fertilizers, contributes to soil pollution. Soil is also depleted, leading to soil degradation. Land resources are being destroyed.

§one. Classification of anthropogenic impacts

Anthropogenic impacts include all impacts that depress the nature, created by technology or directly by humans. They can be combined into the following groups:

1) pollution, i.e. introducing into the environment uncharacteristic for it physical, chemical and other elements or artificially increasing the existing natural level of these elements;

2) technical transformations and destruction of natural systems and landscapes in the process of extraction of natural resources, construction, etc .;

3) withdrawal of natural resources - water, air, minerals, organic fuel, etc .;

4) global climatic impacts;

5) violation of the aesthetic value of landscapes, i.e. change in natural forms, unfavorable for visual perception.

Some of the most significant negative impacts on nature are pollution, which are classified according to type, source, consequences, control measures, etc. Sources of anthropogenic pollution are industrial and agricultural enterprises, energy facilities, transport. Household pollution makes a significant contribution to the overall balance.

Anthropogenic pollution can be local, regional and global. They are divided into the following types:

Biological,

Mechanical,

Chemical,

Physical,

· Physical and chemical.

Biological, as well as microbiological pollution occurs when biological waste enters the environment or as a result of the rapid multiplication of microorganisms on anthropogenic substrates.

Mechanical pollution is associated with substances that do not have physical and chemical effects on organisms and the environment. It is typical for the processes of production of building materials, construction, repair and reconstruction of buildings and structures: it is waste of stone sawing, production of reinforced concrete, bricks, etc. The cement industry, for example, ranks first in terms of emissions of solid pollutants (dust) into the atmosphere, followed by factories for the production of sand-lime bricks, lime plants and porous aggregate factories.

Chemical pollution can be caused by the introduction of any new chemical compounds into the environment or an increase in the concentration of already present substances. Many of the chemicals are active and can interact with the molecules of substances inside living organisms or actively oxidize in air, thus becoming toxic to them. The following groups of chemical contaminants are distinguished:

1) aqueous solutions and slimes with acidic, alkaline and neutral reactions;

2) non-aqueous solutions and sludge (organic solvents, resins, oils, fats);

3) solid pollution (chemically active dust);

4) gaseous pollution (vapors, waste gases);

5) specific - especially toxic (asbestos, compounds of mercury, arsenic, lead, phenol-containing pollution).

Based on the results of international research carried out under the auspices of the United Nations, a list of the most important substances that pollute the environment has been compiled. It included:

§ sulfur trioxide (sulfuric anhydride) SO 3;

Suspended particles;

§ carbon oxides CO and CO 2

§ nitrogen oxides NO x;

§ photochemical oxidants (ozone О 3, hydrogen peroxide Н 2 О 2, hydroxyl radicals ОН -, PAN peroxyacyl nitrates and aldehydes);

§ mercury Hg;

§ lead Pb;

§ cadmium Cd;

§ chlorinated organic compounds;

§ toxins of fungal origin;

§ nitrates, more often in the form of NaNO 3;

§ ammonia NH 3;

§ certain microbial contaminants;

§ radioactive contamination.

According to their ability to survive under external influence, chemical contamination is divided into:

a) persistent and

b) destroyed by chemical or biological processes.

TO physical include pollution:

1) thermal, arising as a result of an increase in temperature due to heat losses in industry, residential buildings, in heating mains, etc.;

2) noise as a result of increased noise of enterprises, transport, etc .;

3) light, arising as a result of unreasonably high illumination created by artificial light sources;

4) electromagnetic from radio, television, industrial installations, power lines;

5) radioactive.

Pollution from various sources enters the atmosphere, water bodies, lithosphere, after which it begins to migrate in different directions. From the habitats of a separate biotic community, they are transferred to all components of the biocenosis - plants, microorganisms, animals. Directions and forms of pollution migration can be as follows (Table 2):

table 2

Forms of migration of pollution between natural environments

Migration direction

Migration forms

Atmosphere - atmosphere Atmosphere - hydrosphere Atmosphere - land surface Atmosphere - biota Hydrosphere - atmosphere Hydrosphere - hydrosphere Hydrosphere - land surface, bottom of rivers, lakes Hydrosphere - biota Land surface - hydrosphere Land surface - land surface Land surface - atmosphere Land surface - biota Biota - atmosphere Biota - hydrosphere Biota - land surface Biota - biota

Transport in the atmosphere Sedimentation (leaching) on ​​the water surface Sedimentation (leaching) on ​​the land surface Sedimentation on the plant surface (foliar intake) Evaporation from water (oil products, mercury compounds) Transport in water systems Transfer from water to soil, filtration, self-purification of water, sedimentation pollution Transition from surface waters to terrestrial and aquatic ecosystems, entering organisms with drinking water Flushing with precipitation, temporary watercourses, during snow melting Migration in soil, glaciers, snow cover Blowing away and transport by air masses Root input of pollution into vegetation Evaporation Intake of water after death organisms Entry into the soil after the death of organisms Migration along food chains

Construction production is a powerful tool destruction of natural systems and landscapes... The construction of industrial and civil facilities leads to the rejection of large areas of fertile land, a reduction in the living space of all ecosystem inhabitants, and a serious change in the geological environment. Table 3 illustrates the results of the impact of construction on the geological structure of the territories.

Table 3

Changes in the geological environment at construction sites

Environmental disturbances are accompanied by the extraction and processing of minerals. This is expressed in the following.

1. Creation of large-scale open pits and embankments leads to the formation of a technogenic landscape, a reduction in land resources, deformation of the earth's surface, impoverishment and destruction of soils.

2. Drainage of deposits, water intake for technical needs of mining enterprises, discharge of mine and waste waters violate the hydrological regime of the water basin, deplete the reserves of underground and surface waters, and worsen their quality.

3. Drilling, blasting, loading of rock mass is accompanied by a deterioration in the quality of atmospheric air.

4. The above processes, as well as industrial noise, contribute to the deterioration of living conditions and a decrease in the number and species composition of plants and animals, and a decrease in crop yields.

5. Mining, drainage of deposits, extraction of minerals, burial of solid and liquid waste lead to a change in the natural stress-strain state of the rock mass, flooding and watering of deposits, pollution of the subsoil.

Nowadays, disturbed territories appear and develop practically in every city. territories with a threshold (supercritical) change in any characteristic of geotechnical conditions. Any such change limits the specific functional use of the area and requires reclamation, i.e. a set of works aimed at restoring the biological and economic value of disturbed lands.

One of the main reasons depletion of natural resources is the extravagance of people. So, according to some experts, the explored reserves of minerals will be completely depleted in 60-70 years. Known oil and gas deposits can be depleted even faster.

At the same time, only 1/3 of the consumed raw materials are directly spent on the production of industrial products, and 2/3 is lost in the form of by-products and waste that pollute the natural environment (Fig. 9).

Throughout the history of human society, about 20 billion tons of ferrous metals have been smelted, and in structures, cars, transport, etc. only 6 billion tons of them were sold. The rest is scattered in the environment. Currently, more than 25% of the annual production of iron is dispersed, and even more of some other substances. For example, the dispersion of mercury and lead amounts to 80 - 90% of their annual production.

NATURAL DEPOSITS

Retrieved Left

Losses

Recycling Partial refund

Partial return

Products

Failure, wear, corrosion

Scrap Environmental pollution

Fig. 9. Resource cycle diagram

The balance of oxygen on the planet is on the verge of disruption: at the current rate of deforestation, photosynthetic plants will soon be unable to reimburse it for the needs of industry, transport, energy, etc.

Global climate change caused by human activities are characterized primarily by a global rise in temperature. Experts believe that in the next decade, the warming up of the earth's atmosphere may increase to a dangerous level: in the tropics, temperatures are predicted to rise by 1-2 0 C, and near the poles by 6-8 0 C.

Due to melting polar ice the level of the oceans will noticeably rise, which will lead to the flooding of huge populated areas and agricultural areas. The associated massive epidemics are predicted, especially in South America, India, the Mediterranean countries. The number of oncological diseases will increase everywhere. The power of tropical cyclones, hurricanes, tornadoes will significantly increase.

The root cause of it all is the greenhouse effect caused by an increase in the concentration in the stratosphere at an altitude of 15-50 km of gases that are usually not present there: carbon dioxide, methane, nitrogen oxides, chlorofluorocarbons. A layer of these gases acts as an optical filter, letting in the sun's rays and retaining thermal radiation reflected from the earth's surface. This causes the temperature to rise in the surface area, as under the roof of a greenhouse. And the intensity of this process is growing: in the last 30 years alone, the concentration of carbon dioxide in the air has increased by 8%, and in the period from 2030 to 2070, its content in the atmosphere is expected to double compared to the pre-industrial level.

Thus, the global temperature rise in the coming decades and the associated adverse events are beyond doubt. At the present level of development of civilization, it is only possible to slow down this process in one way or another. Thus, the all-round saving of fuel and energy resources directly contributes to a slowdown in the rate of atmospheric heating. Further steps in this direction are the transition to resource-saving technologies and devices, to new construction projects.

By some estimates, significant warming has already been delayed by 20 years, thanks to the almost complete cessation of the production and use of chlorofluorocarbons in industrialized countries.

At the same time, there are a number of natural factors that restrain climate warming on Earth, for example, stratospheric aerosol layer, formed by volcanic eruptions. It is located at an altitude of 20-25 km and consists mainly of sulfuric acid droplets with an average size of 0.3 microns. It also contains particles of salts, metals, and other substances.

Particles from the aerosol layer reflect solar radiation back into space, which leads to a slight decrease in temperature in the surface layer. Despite the fact that there are about 100 times less particles in the stratosphere than in the lower atmosphere - the troposphere - they have a more noticeable climatic effect. This is due to the fact that the stratospheric aerosol mainly lowers the air temperature, while the tropospheric aerosol can both lower and increase it. In addition, each particle in the stratosphere exists for a long time - up to 2 years, while the lifetime of tropospheric particles does not exceed 10 days: they are quickly washed out by rains and fall to the ground.

Violation of the aesthetic value of landscapes typical for construction processes: the construction of non-scale natural formations of buildings and structures makes a negative impression, worsens the historically formed appearance of landscapes.

All technogenic impacts lead to a deterioration in the quality indicators of the environment, which are distinguished by conservatism, since they were developed over millions of years of evolution.

To assess the activity of anthropogenic impact on the nature of the Kirov region, an integral anthropogenic load was established for each district, obtained on the basis of assessments of the environmental impact of three types of pollution sources:

§ local (household and industrial waste);

§ territorial (agriculture and forest exploitation);

§ local-territorial (transport).

It has been established that the areas with the highest environmental stress include: Kirov, district and Kirovo-Chepetsk, district and Vyatskiye Polyany, district and Kotelnich, district and Slobodskoy.

The answer left a guest

1. The zone of equatorial forests in South America occupies gigantic areas of the Amazon lowland, the adjacent foothills of the Eastern Andes, the northern part of the Pacific coast in the equatorial climatic zone. These forests are called selvas, which means “forests” in Portuguese. A. Humboldt suggested calling them giley (from the Greek “gileyon” - forest).

2. Zones of savannas, woodlands and shrubs are located mainly in the subequatorial and partly in the tropical climatic zones. The savannahs occupy the Orinoco Plain, where they are called llanos, as well as the interior of the Guiana and Brazilian Highlands (campos).

3. The zone of subtropical steppes, which are called pampa here, is located south of the savannahs of the tropical belt. The soils in the pampa are reddish-black, formed as a result of the decomposition of dense vegetation from turf grasses - pampas grass, feather grass, bluegrass, etc. These soils have a significant humus horizon (up to 40 cm) and are very fertile. Fast-running animals are typical for the natural areas of the pampa - pampas deer, pampas cat, llamas. There are many rodents along the banks of rivers and lakes - nutria, whiskey. At present, the natural landscapes in the pampa have been little preserved: comfortable lands are plowed up (fields of wheat, corn), dry steppes are divided into huge corrals for cattle.

4. The semi-desert zone of the temperate zone prevails in the southern - narrowed part of the continent, in Patagonia. Patagonia is in the "rain shadow" of the Andes. In a dry continental climate, unclosed vegetation cover is widespread on gray-brown soils (saline in places). It is formed by dense sod grasses (bluegrass, feather grass, fescue) and shrubs that form thorny cushions (undersized cacti, ephedra, verbena). Among the endemic representatives of the fauna of Patagonia, it is necessary to note the skunk, the Magellanic dog (similar to a fox), the Darwin ostrich (the southern species of the rhea). There are Pampas cat and armadillos, small rodents (tuko-tuko, mara, etc.).

5. The Andes are characterized by high-altitude zonation of landscapes. Sections of the Andes, lying at different latitudes, differ in the number and composition of altitudinal belts. The most complete range of altitudinal zones is presented in the equator.

6. Zone of broad-leaved and coniferous forests(this is in the south of Chile)

Along the Pacific coast, there is a special change in meridional natural zones: in tropical latitudes, a zone of deserts and semi-deserts of the tropical belt is formed (in the Atacama, a scrap formation is formed, which is characterized by bulbous and tuberous ephemeroids); in the subtropical zone between 32-38 ° S. sh. there is a zone of dry, hard-leaved Mediterranean forests and shrubs. South of 38 ° S sh. in the subtropical zone - a zone of constantly humid evergreen forests (hemigili zone), which extends to the south and into the temperate zone up to 46 ° S. sh. Hemigileia consist of evergreen southern beeches, Chilean araucaria, “Chilean cypress trees” and other tree species.

"Brazil" - Sloth - also a resident of Brazil. From Liverpool Harbor, always on Thursdays, Ships sail to the distant runners. The battleship lives in burrows. And in case of danger, the armadillo can curl up into a ball like a hedgehog. They speak in Brazil in Portuguese. The sloth has long and thin legs with 3 toes with very long claws.

"Natural areas of South America" ​​- Relief. Changes in the nature of the continent under the influence of man. You probably guessed it. That's right, the unique nature of South America On the verge of gradual destruction. Why do we say that. Hundreds of species are included in the Red Book. Soils. Climate. Crocodile native to South America. 11, Wood-rubber plant. 12.

"Lessons from South America" ​​- Useful Internet Links. Lesson objectives: Development of algorithmic and logical thinking techniques. Natural resources (announcer, text, map, video). Multimedia textbook. Contents Handbook Practice Tests Online. The content of the multimedia textbook. Fauna of South America -10 min. Lesson conclusions.

"Geography grade 7 South America" ​​- Table. Lesson flow: South America. GP South America. Common features and differences in GP. Lesson topic. introduction teachers …………. SOUTH AMERICA Grade 7. Working with the table. Explorers and travelers.

"Mainland South America" ​​- Oil is produced on the shores of Lake Maracaibo. 11. Assignment 3: "Do you believe - do not believe?". Put the “+” sign if it is true, and “-” if the statement is not true. Generalizing lesson

human impact on nature

1. Resettlement of mankind on the territory of the Earth

2. Anthropogenic impact on the nature of Africa

3. Anthropogenic impact on the nature of Eurasia

4. Anthropogenic impact on the nature of North America

5. Anthropogenic impact on the nature of South America

6. Anthropogenic impact on the nature of Australia and Oceania

* * *

1. SETTLEMENT OF HUMANITY ON EARTH

Africa is considered the most likely ancestral home modern man.

Many features of the nature of the continent speak in favor of this position. African apes - especially chimpanzees - have the most biological characteristics in common with modern humans compared to other anthropoids. Fossils of several forms of the great apes of the family have also been found in Africa pongid(Pongidae), similar to modern apes. In addition, fossil forms of anthropoids - australopithecines, usually included in the hominid family - have been discovered.

Remains Australopithecus found in the Villafran deposits of South and East Africa, that is, in those strata that most researchers attribute to the Quaternary period (Eopleistocene). In the east of the mainland, along with the bones of Australopithecus, stones with traces of rough artificial spalling were found.

Many anthropologists consider Australopithecus as a stage of human evolution, preceding the appearance of the most ancient people. However, the discovery of R. Leakey in 1960 of the Olduvai locality made significant changes in solving this problem. In the natural section of the Olduvai Gorge, located in the southeast of the Serengeti Plateau, near the famous Ngorongoro Crater (northern Tanzania), in the volcanic rocks of the Villafranchian age, the remains of primates close to the Australopithecus were found. They got the name zinjantropov... Below and above the zinjanthropus, the skeletal remains of the prezinjanthropus, or Homo habilis (Homo habilis), were found. Together with the prezinjanthrop, primitive stone products were found - roughly upholstered pebbles. In the overlying layers of the Olduvai locality, the remains of African archantropus, and on the same level with them - Australopithecus. The mutual position of the remains of prezinjanthropus and zinjanthropus (australopithecines) suggests that the australopithecines, previously considered the direct ancestors of ancient people, actually formed a non-progressive branch of hominids that existed for a long time between the Villafranchian and the middle of the Pleistocene. This branch has ended dead end.

In the last 100 years, humanity has begun to have a noticeable impact on the functioning of the biosphere.

In the prehistoric phase, people lived in conditions of energy deficiency and were forced to guard a huge forage area, in which they periodically or constantly roamed. And, despite this, for a long time they were within the framework of a very modest energy balance.

Energy consumption per person (kcal / day) in the Stone Age was about 4 thousand, in an agrarian society - 12 thousand, in the industrial era - 70 thousand, and in advanced developed countries of the end of the twentieth century - 230-250 thousand, t .e. 58-62 times more than that of our distant ancestors.

Population growth requires more food, job creation and industrial expansion. At the first stages, man interacted with the natural environment as an ordinary biological species, as an animal, and as a whole was a part of the ecosystem, as its constituent element. A person mainly used the resources around him and practically did not affect either their quantity or their quality, and could not have any tangible impact on nature, both due to his small number and the presence of any significant means of influencing the components of the environment. ...

Having formed a human society, it went through the following stages of interaction with nature:

The transition to the production and use of tools of labor as the first (link in the relationship between people and nature;

The transition to artificial energy production, which expanded (opportunities in the transformation of nature;

Industrial and scientific and technological revolution;

Artificial reproduction and preservation of the environment - the protonosphere.

At the end of the second millennium, population growth, and mainly a qualitative leap in the development of science and technology, led to the fact that anthropogenic impacts in terms of their importance for the biosphere reached the same level as natural ones on a planetary scale. The transformation of landscapes into cities and other human settlements, into agricultural lands and industrial complexes has already covered more than 20% of the land area. Oxygen consumption in industry and transport is, on the scale of the entire biosphere, about 10% of the planetary production of photosynthesis; in some countries, man-made oxygen consumption exceeds its production by plants. In our time, anthropogenic impact is becoming a guiding force for the further evolution of ecosystems.

Anthropogenic impact subdivided into:

pollution- introducing into the environment new physical, chemical or biological agents (elements, compounds, substances, objects) uncharacteristic for it or exceeding the existing natural level of these agents;

technical transformations and destruction of natural systems and landscapes - in the process of extracting natural resources, during agricultural work, construction, etc .;

depletion of natural resources(minerals, water, air, biological components of ecosystems);

global climate impacts(climate change due to human economic activity);

aesthetic disorders(change in natural forms, unfavorable for visual and other perception; destruction of historical and cultural values, etc.).

As a result, a person affects the biosphere and changes the composition, circulation and balance of substances; heat balance of the near-surface part of the Earth; the structure of the earth's surface (during agricultural work, moving open rocks; excavation of quarries, as a result of urban development, during road construction; during the construction of artificial reservoirs - canals, reservoirs, land reclamation, etc.); exterminating, as well as moving to new habitats a number of animal species and plant varieties.

In conditions of anthropogenic loads for the sustainable functioning of ecosystems, a person must himself play the role of a compensatory regulator, greening the land in places of deforested forests, purifying water, air, etc.

Pollution subdivided, depending on the type, source, consequences and control measures, into: waste water and other impurities that absorb oxygen; carriers of infection; substances that are of nutritional value to plants; minerals and inorganic acids and salts; solid drains; radioactive substances, etc.

It should be noted that, in principle, pollution can be natural, arising as a result of powerful natural processes - volcanic eruptions with huge mass emissions of dust, ash, gases, steam, etc .; forest and steppe fires; floods; dust and sand storms, etc.

It is necessary to dwell on such an important concept, which is widely used in modern ecological and environmental literature, as pollutant. It is understood as any physical agent, chemical substance or biological species (mainly microorganisms) that enters the environment or arises in it in an amount that goes beyond usual, and causing pollution. Allocate natural (natural , anthropogenic, as well as primary (directly from the source of pollution and secondary (during the decomposition of primary, or chemical reactions with them). Also distinguishes persistent (non-decomposing pollutants that accumulate in trophic chains.

The release of various pollutants into the natural environment can have a number of undesirable consequences: damage to vegetation and fauna (decrease in the productivity of forests and cultivated plants, the extinction of animals); violation of the stability of natural biogeocenoses; damage to property (corrosion of metals, destruction of architectural structures, etc.); harm to human health, etc.

Many of the pollutants (pesticides, half-chlorobiphenyls, plastics) decompose extremely slowly under natural conditions, and toxic compounds (mercury, lead) are not neutralized at all.

If, until the 40s of the XX century, natural products still dominated (cotton, silk, wool, soap, rubber, food, free of: additives, etc.), now in industrialized countries, they are replaced by synthetic ones, which difficult or incompletely biodegradable and contaminates the environment. These are primarily synthetic fibers, detergents (detergents, bleaches), food with additives, mineral fertilizers, synthetic rubber, etc.

Especially a lot of pollutants entering the environment are generated when energy is obtained from the combustion of fossil fuels. Man, releasing solar energy in this way, accelerates the circulation of substances and energy in nature. Industrial waste and atmospheric pollutants (carbon monoxide, nitrogen oxides, hydrocarbons, particulate matter, etc.) disrupt the natural carbon cycle, contributing to a number of negative consequences (greenhouse effect, photochemical smog, etc.). A large number of pollutants enter the atmosphere from various industries, in particular, metallurgical enterprises of the world annually emit more than 150 thousand tons of copper, 120 thousand tons of zinc, 90 thousand tons of nickel, cobalt, mercury. Thus, the Norilsk Mining and Metallurgical Combine annually emits into the atmosphere only sulfur compounds up to 2,200 thousand tons, which leads to the death of a significant number of plant communities, creating a significant threat to the health and life of many other living organisms. Within a radius of up to 120 km o: the plant has no natural regeneration of trees, and the annual growth and primary biological productivity are minimal.

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Anthropogenic impact on nature

environmental atmosphere pollutant

Introduction

5. Radiation in the biosphere

Conclusion

Introduction

Man has always used the environment mainly as a source of resources, but for a very long time his activities did not have a noticeable effect on the biosphere. Only at the end of the last century, changes in the biosphere under the influence of economic activity attracted the attention of scientists. In the first half of the 20th century, these changes were growing and at present they have fallen into an avalanche on human civilization. Striving to improve the conditions of his life, a person constantly increases the rate of material production, without thinking about the consequences. With this approach, most of the resources taken from nature are returned to it in the form of waste, often poisonous or unsuitable for disposal. This poses a threat to both the existence of the biosphere and of man himself.

Humanity in the process of life, of course, affects various ecological systems. Examples of such, most often hazardous, impacts are drainage of bogs, deforestation, destruction of the ozone layer, river currents, and waste disposal into the environment. By this, a person destroys the established connections in a stable system, which can lead to its destabilization, that is, to an environmental catastrophe.

Currently, the entire territory of our planet is subject to various anthropogenic influences.

Anthropogenic impact on nature - various forms the impact of human activities on nature. Its effects cover individual components of nature and natural complexes. Anthropogenic impacts can be both positive and negative; the latter necessitates the use of special environmental protection measures.

1. The current state of the natural environment

With the emergence and development of mankind, the process of evolution has noticeably changed. In the early stages of civilization, deforestation and burning of forests for agriculture, cattle grazing, hunting and hunting for wild animals, wars devastated entire regions, led to the destruction of plant communities, the extermination of certain species of animals. With the development of civilization, especially the turbulent after the industrial revolution at the end of the Middle Ages, mankind acquired ever greater power, an ever greater ability to involve and use huge masses of matter - both organic, living, and mineral, inert to satisfy its growing needs.

Population growth and the expanding development of agriculture, industry, construction, transport caused massive destruction of forests in Europe and North America. Cattle grazing on a large scale led to the death of forests and grass cover, to erosion of the soil layer (Central Asia, North Africa, southern Europe and the United States). Dozens of animal species were exterminated in Europe, America, Africa.

Scientists suggest that the depletion of soils on the territory of the ancient Central American state of the Maya as a result of slash-and-burn agriculture was one of the reasons for the death of this highly developed civilization. Similarly in Ancient Greece extensive forests disappeared as a result of deforestation and excessive grazing. This has exacerbated soil erosion and led to the destruction of soil cover on many mountain slopes, increased climate aridity and worsened agricultural conditions.

The construction and operation of industrial enterprises, the extraction of minerals have led to serious violations of natural landscapes, pollution of soil, water, air with various wastes.

Real shifts in biospheric processes began in the 20th century. as a result of the next industrial revolution. The rapid development of energy, mechanical engineering, chemistry, transport has led to the fact that human activity has become comparable in scale with natural energy and material processes occurring in the biosphere. The intensity of human consumption of energy and material resources grows in proportion to the size of the population and even outstrips its growth.

As a result of the combustion of various fuels, about 20 billion tons of carbon dioxide are emitted into the atmosphere annually and the corresponding amount of oxygen is absorbed. The natural reserve of CO2 in the atmosphere is about 50,000 billion tons. This value fluctuates and depends, in particular, on volcanic activity. However, anthropogenic carbon dioxide emissions exceed natural ones and currently account for a large share of its total amount. An increase in the concentration of carbon dioxide in the atmosphere, accompanied by an increase in the amount of aerosol, can lead to noticeable changes in climate and, accordingly, to the disruption of the equilibrium bonds that have developed over millions of years in the biosphere.

The result of a violation of the transparency of the atmosphere, and, consequently, of the heat balance, may be the appearance of a "greenhouse effect", that is, an increase average temperature atmosphere by a few degrees. This can cause melting of the glaciers of the polar regions, an increase in the level of the World Ocean, changes in its salinity, temperature, global climate disturbances, flooding of coastal lowlands and many other adverse consequences.

The emission of industrial gases into the atmosphere, including such compounds as carbon monoxide, oxides of nitrogen, sulfur, ammonia and other pollutants, leads to the suppression of the vital activity of plants and animals, metabolic disorders, poisoning and death of living organisms.

An uncontrollable influence on the climate, combined with irrational agriculture, can lead to a significant decrease in soil fertility, large fluctuations in crop yields. According to UN experts, in recent years, fluctuations in agricultural production have exceeded 1%. But a decrease in food production even by 1% can lead to the death of tens of millions of people from hunger.

The forests on our planet are catastrophically reduced. Irrational deforestation and fires have led to the fact that in many places, once completely covered with forests, to date they have survived only on 10-30% of the territory. The area of ​​tropical forests in Africa has decreased by 70%, South America - by 60%, in China, only 8% of the territory is covered with forest.

At present, the total power of anthropogenic pollution sources in many cases exceeds the power of natural ones. Thus, natural sources of nitric oxide emit 30 million tons of nitrogen per year, and anthropogenic sources - 35-50 million tons; sulfur dioxide, respectively, about 30 million tons and more than 150 million tons. As a result of human activity, lead enters the biosphere almost 10 times more than in the process of natural pollution.

Pollutants arising from human activities and their impact on the environment are very diverse. These include: compounds of carbon, sulfur, nitrogen, heavy metals, various organic substances, artificial materials, radioactive elements and much more.

Thus, according to experts, about 10 million tons of oil gets into the ocean annually. Oil on water forms a thin film that prevents gas exchange between water and air. While settling to the bottom, oil gets into bottom sediments, where it disrupts the natural processes of life of bottom animals and microorganisms. In addition to oil, there has been a significant increase in the release into the ocean of domestic and industrial wastewater containing, in particular, such hazardous pollutants as lead, mercury, arsenic, which have a strong toxic effect. The background concentrations of such substances in many places have already been exceeded tenfold.

Each pollutant has a certain negative impact on nature, so their release into the environment must be strictly controlled. The legislation establishes for each pollutant the maximum permissible discharge (MPD) and the maximum permissible concentration (MPC) in the natural environment.

The maximum permissible discharge (MPD) is the mass of a pollutant emitted by individual sources per unit of time, the excess of which leads to adverse consequences in the environment or is dangerous to human health.

The maximum permissible concentration (MPC) is understood as the amount of a harmful substance in the environment that does not adversely affect the health of a person or his offspring with constant or temporary contact with him. At present, when determining the MPC, not only the degree of influence of pollutants on human health is taken into account, but also their effect on animals, plants, fungi, microorganisms, as well as on the natural community as a whole.

Special environmental monitoring (observation) services monitor compliance with the established MPD and MPC standards for hazardous substances. Such services have been established in all regions of the country. Their role is especially important in large cities, near chemical plants, nuclear power plants and other industrial facilities. Monitoring services have the right to apply the measures provided for by law, up to and including the suspension of production and any work, if environmental protection standards are violated.

In addition to environmental pollution, anthropogenic impact is expressed in the depletion of natural resources of the biosphere. The enormous use of natural resources has led to significant changes in landscapes in some regions (for example, in coal basins). If at the dawn of civilization man used only about 20 chemical elements for his needs, at the beginning of the XX century. about 60, now more than 100 - almost the entire periodic table. About 100 billion tons of ore, fuel, and mineral fertilizers are mined annually (extracted from the geosphere).

The rapid growth in demand for fuel, metals, minerals and their extraction has led to the depletion of these resources. So, according to experts, while maintaining the current rates of production and consumption, proven oil reserves will be exhausted in 30 years, gas - in 50 years, coal - in 200. A similar situation has developed not only with energy resources, but also with metals (depletion of reserves aluminum is expected in 500-600 years, iron - 250 years, zinc - 25 years, lead - 20 years) and mineral resources such as asbestos, mica, graphite, sulfur.

Here is a far from complete picture of the ecological situation on our planet at the present time. Even individual successes in nature conservation cannot noticeably change the general course of the process of the detrimental influence of civilization on the state of the biosphere.

2. The atmosphere is the outer shell of the biosphere. Air pollution

The mass of the atmosphere of our planet is negligible - only one millionth of the mass of the Earth. However, its role in the natural processes of the biosphere is enormous. 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. The circulation of the atmosphere 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 minor amounts of inert gases (neon, helium, krypton, xenon), ammonia, methane, ozone, sulfur dioxides and other gases. Along with gases, the atmosphere contains solid particles coming from the Earth's surface (for example, combustion products, 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.

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.

· Oxygen plays an essential role in the life of most living organisms on our planet. Everyone needs it for breathing.

Oxygen has not always been part of the earth's atmosphere. It appeared as a result of the vital activity of photosynthetic organisms. Under the influence of ultraviolet rays, it turned into ozone. With the accumulation of ozone, the formation of the ozone layer took place in the upper atmosphere. The ozone layer, like a shield, reliably protects the Earth's surface from ultraviolet radiation, which is fatal to living organisms. The modern atmosphere contains hardly twenty 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. In the atmosphere, apparently, an approximate balance has developed between the production of oxygen in the process of photosynthesis and its consumption by living organisms. But recently there has been a danger that as a result of human activity, the oxygen reserves in the atmosphere may decrease. The destruction of the ozone layer, which has been observed in recent years, poses a particular danger. Most scientists associate this with human activities.

The oxygen cycle in the biosphere is extremely difficult, as it reacts with it a large number of organic and inorganic substances, as well as hydrogen, combining with which oxygen forms water.

· Carbon dioxide (carbon dioxide) is used in the process of photosynthesis to form organic matter.

It is thanks to this process that the carbon cycle in the biosphere is closed. Like oxygen, carbon is a part of soils, plants, animals, and participates in various mechanisms of the circulation of substances in nature. The content of carbon dioxide in the air that we breathe is about the same in different parts of the planet. The exception is large cities in which the content of this gas in the air is higher than normal.

Some fluctuations in the content of carbon dioxide in the air of the area depend on the time of day, season of the year, biomass of vegetation. At the same time, studies show that since the beginning of the century, the average content of carbon dioxide in the atmosphere, albeit slowly, but steadily increases.

· Nitrogen is an irreplaceable biogenic element, since it is a part of proteins and nucleic acids.

The atmosphere is an inexhaustible reservoir of nitrogen, but the bulk of living organisms cannot use this nitrogen directly: it must first be bound in the form of chemical compounds.

Part of nitrogen comes from the atmosphere into ecosystems in the form of nitrogen oxide, which is formed by electrical discharges during thunderstorms. However, the main part of nitrogen enters water and soil as a result of its biological fixation. There are several types of bacteria and blue-green algae (fortunately, very numerous) that are capable of fixing atmospheric nitrogen. As a result of their activity, as well as due to the decomposition of organic residues in the soil, autotrophic plants are able to assimilate the necessary nitrogen.

The nitrogen cycle is closely related to the carbon cycle. Although the nitrogen cycle is more complex than the carbon cycle, it tends to be faster.

Other constituents of air do not participate in biochemical cycles, but the presence of large amounts of pollutants in the atmosphere can seriously disrupt these cycles.

Various negative changes in the Earth's atmosphere are mainly associated with changes in the concentration of minor components of atmospheric air.

There are two main sources of air pollution: natural and anthropogenic.

· The natural source is volcanoes, dust storms, weathering, forest fires, decomposition of plants and animals.

· The main anthropogenic sources of air pollution include enterprises of the fuel and energy complex, transport, various machine-building enterprises.

According to scientists, every year in the world as a result of human activity, 25.5 billion tons of carbon oxides, 190 million tons of sulfur oxides, 65 million tons of nitrogen oxides, 1.4 million tons of chlorofluorocarbons (freons ), organic lead compounds, hydrocarbons, including carcinogenic ones.

In addition to gaseous pollutants, a large amount of particulate matter is emitted into the atmosphere. These are dust, soot and soot. Pollution of the natural environment with heavy metals is fraught with great danger. Lead, cadmium, mercury, copper, nickel, zinc, chromium, vanadium have become practically permanent components of the air in industrial centers. The problem of air pollution with lead is especially acute.

Global air pollution affects the state of natural ecosystems, especially the green cover of our planet. Forests are one of the most vivid indicators of the state of the biosphere.

Acid rains, mainly caused by sulfur dioxide and nitrogen oxides, cause enormous damage to forest biocenoses. It has been established that conifers suffer from acid rain to a greater extent than broad-leaved ones.

Only on the territory of our country total area of forests affected by industrial emissions reached 1 million hectares. A significant factor of forest degradation in recent years is environmental pollution by radionuclides. Thus, as a result of the accident at the Chernobyl nuclear power plant, 2.1 million hectares of forests were affected.

Green spaces are especially affected in industrial cities, the atmosphere of which contains a large amount of pollutants.

The airborne environmental problem of the depletion of the ozone layer, including the appearance of ozone holes over Antarctica and the Arctic, is associated with the excessive use of freons in production and everyday life.

3. Soil is an important component of the biosphere. Soil pollution

Soil - the top layer of land, formed under the influence of plants, animals, microorganisms and climate from the parent rocks on which it is located. It is an important and complex component of the biosphere, closely related to its other parts.

The following main components interact in a complex way in soil:

· Mineral particles (sand, clay), water, air;

Detritus - dead organic matter, the remains of the vital activity of plants and animals;

· Many living organisms - from detritus feeders to decomposers, decomposing detritus to humus.

Thus, soil is a bio-inert system based on dynamic interactions between mineral components, detritus, detritus feeders, and soil organisms.

In its development and formation of the soil, there are several stages.

Young soils are usually the result of weathering of parent rocks or the transfer of sedimentary deposits (eg alluvium). Microorganisms, pioneer plants - lichens, mosses, grasses, small animals settle on these substrates. Gradually, other species of plants and animals are introduced, the composition of the biocenosis becomes more complicated, a whole series of interrelationships arise between the mineral substrate and living organisms. The result is a mature soil whose properties depend on the original parent rock and climate.

The process of soil development ends when equilibrium is achieved, the conformity of the soil with the vegetation cover and the climate, that is, a state of climax occurs. Thus, changes in the soil that occur during its formation resemble the successional changes in ecosystems.

Each type of soil corresponds to certain types of plant communities. Thus, pine forests tend to grow on light sandy soils, while spruce forests prefer heavier, nutrient-rich loamy soils.

The soil is like a living organism, inside which various complex processes take place. In order to keep the soil in good condition, it is necessary to know the nature of the metabolic processes of all its components.

The surface layers of the soil usually contain many residues of plant and animal organisms, the decomposition of which leads to the formation of humus. The amount of humus determines the fertility of the soil.

The soil is inhabited by a great variety of different living organisms - edaphobionts, which form a complex food detritus network: bacteria, micro-fungi, algae, protozoa, molluscs, arthropods and their larvae, earthworms and many others. All these organisms play a huge role in the formation of soil and changes in its physicochemical characteristics.

Plants absorb the necessary minerals from the soil, but after the death of plant organisms, the removed elements return to the soil. Soil organisms gradually recycle all organic residues. Thus, in natural conditions, there is a constant circulation of substances in the soil.

In artificial agrocenoses, such a cycle is disrupted, since a person withdraws a significant part of agricultural products, using it for his own needs. Due to the non-participation of this part of the production in the cycle, the soil becomes sterile. To avoid this and increase soil fertility in artificial agrocenoses, people apply organic and mineral fertilizers.

Under normal natural conditions, all processes occurring in the soil are in balance. But often a person is guilty of disturbing the equilibrium state of the soil. As a result of the development of human economic activity, pollution, changes in the composition of the soil and even its destruction occur. Currently, there is less than one hectare of arable land for every inhabitant of our planet. And these insignificant areas continue to decline due to inept human economic activity.

Vast areas of fertile land perish during mining operations, during the construction of enterprises and cities. The destruction of forests and natural grassy cover, repeated plowing of the land without observing the rules of agricultural technology leads to the emergence of soil erosion - the destruction and washout of the fertile layer by water and wind. Erosion is now a worldwide evil. It is estimated that in the last century alone, as a result of water and wind erosion, 2 billion hectares of fertile lands of active agricultural use have been lost on the planet.

One of the consequences of the intensification of human production activity is the intensive pollution of the soil cover. The main soil pollutants are metals and their compounds, radioactive elements, as well as fertilizers and pesticides used in agriculture.

The most dangerous soil pollutants include mercury and its compounds. Mercury enters the environment with pesticides, industrial waste containing metallic mercury and its various compounds.

Lead contamination of soils is even more widespread and dangerous. It is known that during the smelting of one ton of lead, up to 25 kg of lead are released into the environment with waste. Lead compounds are used as additives to gasoline, making motor vehicles a significant source of lead pollution. Lead is especially abundant in soils along major motorways.

Soils near large centers of ferrous and nonferrous metallurgy are contaminated with iron, copper, zinc, manganese, nickel, aluminum and other metals. In many places, their concentration is tens of times higher than the MPC.

Radioactive elements can enter the soil and accumulate in it as a result of precipitation from atomic explosions or during the disposal of liquid and solid waste from industrial enterprises, nuclear power plants or research institutions related to the study and use of atomic energy. Radioactive substances from the soil enter plants, then into the organisms of animals and humans, accumulate in them.

Modern agriculture has a significant impact on the chemical composition of soils, which widely uses fertilizers and various chemicals to control pests, weeds and plant diseases. At present, the amount of substances involved in the circulation in the process of agricultural activity is approximately the same as in the process of industrial production. At the same time, the production and use of fertilizers and pesticides in agriculture is increasing every year. Unskillful and uncontrolled use of them leads to disruption of the circulation of substances in the biosphere.

Persistent organic compounds used as pesticides are especially dangerous. They accumulate in soil, water, bottom sediments of water bodies. But most importantly, they are included in ecological food chains, pass from soil and water into plants, then into animals, and ultimately enter the human body with food.

4. Water is the basis of life processes in the biosphere. Pollution of natural waters

Water is the most abundant inorganic compound on our planet. Water is the basis of all life processes, the only source of oxygen in the main driving process on Earth - photosynthesis. Water is present in the entire biosphere: not only in water bodies, but also in the air and soil, and in all living things. The latter contain up to 80-90% of water in their biomass. The loss of 10-20% of water by living organisms leads to their death.

In its natural state, water is never free from impurities. Various gases and salts are dissolved in it, there are suspended solid particles. 1 liter of fresh water can contain up to 1 g of salts.

Most of the water is concentrated in the seas and oceans. Fresh water accounts for only 2%. Most of the fresh water (85%) is concentrated in the ice of the polar zones and glaciers. The renewal of fresh water occurs as a result of the water cycle.

With the advent of life on Earth, the water cycle has become relatively complex, since more complex processes associated with the vital activity of living organisms have been added to the simple phenomenon of physical evaporation (the transformation of water into steam). In addition, the role of man, as he develops, becomes more and more significant in this cycle.

The water cycle in the biosphere is as follows:

Water falls to the surface of the Earth in the form of precipitation, formed from the water vapor of the atmosphere.

§ A certain part of the deposited precipitation evaporates directly from the surface, returning to the atmosphere with water vapor.

§ The other part penetrates into the soil, is absorbed by the roots of plants and then, passing through the plants, evaporates during the process of transpiration.

§ The third part seeps into the deep layers of the subsoil to the impermeable horizons, replenishing the groundwater.

§ The fourth part in the form of surface, river and underground runoff flows into water bodies, from where it also evaporates into the atmosphere.

Finally, some are used by animals and consumed by humans for their own needs.

All evaporated and returned to the atmosphere water condenses and falls again as precipitation.

Thus, one of the main ways of the water cycle - transpiration, that is, biological evaporation, is carried out by plants, supporting their vital activity. The amount of water released as a result of transpiration depends on the type of plants, the type of plant communities, their biomass, climatic factors, the season and other conditions.

The intensity of transpiration and the mass of water evaporating in this case can reach very significant values. In such communities as forests (with a large phytomass and leaf surface) or swamps (with a water-saturated moss surface), transpiration is generally quite comparable to the evaporation of open water bodies (the ocean) and often even exceeds it.

The amount of total evaporation (from the soil, from the surface of plants and through transpiration) depends on the physiological characteristics of plants and their biomass, therefore it serves as an indirect indicator of the vital activity and productivity of communities.

The pollution of water bodies means a decrease in their biospheric functions and economic value as a result of the intake of harmful substances into them.

One of the main water pollutants is oil and oil products. Oil can get into the water as a result of its natural discharges in the areas of occurrence. But the main sources of pollution are associated with human activities: oil production, transportation, refining and use of oil as fuel and industrial raw materials.

Among industrial products, toxic synthetic substances occupy a special place in terms of their negative impact on the aquatic environment and living organisms. They are finding ever more widespread use in industry, transport, and public utilities. The concentration of these compounds in wastewater, as a rule, is 5-15 mg / l with an MPC of 0.1 mg / l. These substances can form a layer of foam in water bodies, which is especially noticeable on rapids, rifts, sluices. Foaming ability of these substances appears already at a concentration of 1-2 mg / l.

Other pollutants include metals (for example, mercury, lead, zinc, copper, chromium, tin, manganese), radioactive elements, pesticides from agricultural fields, and waste from livestock farms.

Expanded production (without treatment facilities) and the use of pesticides in the fields lead to severe pollution of water bodies with harmful compounds. Pollution of the aquatic environment occurs as a result of the direct introduction of pesticides during the treatment of reservoirs for pest control, the ingress of water flowing from the surface of the treated agricultural lands into reservoirs, when waste products of manufacturing enterprises are discharged into reservoirs, as well as as a result of losses during transportation, storage and partially from atmospheric precipitation.

Along with pesticides, agricultural wastewater contains a significant amount of fertilizer residues (nitrogen, phosphorus, potassium) applied to the fields. In addition, large amounts of organic compounds of nitrogen and phosphorus enter with wastewater from livestock farms, as well as with sewage. An increase in the concentration of nutrients in the soil leads to a violation of the biological balance in the reservoir.

Initially, the number of microscopic algae increases sharply in such a reservoir. With an increase in the food supply, the number of crustaceans, fish and other aquatic organisms increases. Then a huge number of organisms die off. It leads to the consumption of all oxygen reserves contained in the water, and the accumulation of hydrogen sulfide. The situation in the reservoir changes so much that it becomes unsuitable for the existence of any forms of organisms. The reservoir gradually "dies".

Thermal pollution is one of the types of water pollution. Power plants and industrial enterprises often discharge heated water into a reservoir. This leads to an increase in the temperature of the water in it. As the temperature rises in the reservoir, the amount of oxygen decreases, the toxicity of water pollutants increases, and the biological balance is disturbed.

In polluted water, as the temperature rises, pathogens and viruses begin to proliferate. Once in drinking water, they can cause outbreaks of various diseases.

In a number of regions, groundwater was an important source of fresh water. Previously, they were considered the cleanest. But at present, as a result of human economic activity, many sources of groundwater are also being polluted. Often this pollution is so great that the water from them has become undrinkable.

Humanity consumes a huge amount of fresh water for its needs. Its main consumers are industry and agriculture. The most water-intensive industries are mining, steel, chemical, petrochemical, pulp and paper, and food. They consume up to 70% of all water used in industry. The main consumer of fresh water is agriculture: 60-80% of all fresh water is consumed for its needs.

V modern conditions human needs for water for household needs are greatly increasing. The volume of water consumed for these purposes depends on the region and the standard of living, ranged from 3 to 700 liters per person.In Moscow, for example, there are about 650 liters for each inhabitant, which is one of the highest rates in the world.

From the analysis of water use over the past 5-6 decades, it follows that the annual increase in irretrievable water consumption, in which the used water is irretrievably lost to nature, is 4-5%. Prospective calculations show that if such consumption rates are maintained and taking into account population growth and production volumes, by 2100 mankind can exhaust all reserves of fresh water.

Already at the present time, not only territories that nature has deprived of water resources are experiencing a lack of fresh water, but also many regions that were recently considered prosperous in this regard. Currently, the need for fresh water is not met by 20% of the urban and 75% of the rural population of the planet.

Human intervention in natural processes has affected even large rivers (such as the Volga, Don, Dnieper), changing the volume of transported water masses downward (river runoff). Most of the water used in agriculture is used for evaporation and the formation of plant biomass and therefore does not return to rivers. Already, in the most inhabited regions of the country, the river flow has decreased by 8%, and in such rivers as the Don, Terek, Ural - by 11-20%. The fate of the Aral Sea, in fact, ceased to exist due to the excessive withdrawal of water from the Syr Darya and Amu Darya rivers for irrigation, is very dramatic.

The limited supply of fresh water is further diminished by pollution. The main hazard is wastewater (industrial, agricultural and domestic), since a significant part of the used water is returned to water basins in the form of wastewater.

5. Radiation in the biosphere

Radiation pollution has a significant difference from others. Radioactive nuclides are nuclei of unstable chemical elements that emit charged particles and short-wave electromagnetic radiation. It is these particles and radiation that, when entering the human body, destroy cells, as a result of which various diseases, including radiation, can occur.

There are natural sources of radioactivity everywhere in the biosphere, and man, like all living organisms, has always been exposed to natural radiation. External exposure occurs due to radiation of cosmic origin and radioactive nuclides in the environment. Internal exposure is created by radioactive elements that enter the human body with air, water and food.

To quantitatively characterize the effect of radiation on a person, units are used - the biological equivalent of an X-ray (rem) or a sievert (Sv): 1 Sv = 100 rem. Since radioactive radiation can cause serious changes in the body, everyone should know the permissible doses.

As a result of internal and external irradiation, a person receives an average dose of 0.1 rem during the year and, therefore, about 7 rem in his entire life. At these doses, radiation does not harm humans. However, there are areas where the annual dose is higher than the average. So, for example, people living in high-mountainous regions, due to cosmic radiation, can receive a dose several times larger. Large doses of radiation can be in areas where the content of natural radioactive sources is high. For example, in Brazil (200 km from São Paulo) there is a hill where the annual dose is 25 rem. This area is uninhabited.

The greatest danger is posed by radioactive contamination of the biosphere as a result of human activities. Currently, radioactive elements are widely used in various fields. Negligence in the storage and transportation of these elements leads to serious radioactive contamination. Radioactive contamination of the biosphere is also associated with tests of atomic weapons.

In the second half of our century, nuclear power plants, icebreakers, submarines with nuclear installations began to be commissioned. During normal operation of nuclear power facilities and industry, environmental pollution by radioactive nuclides is an insignificant fraction of the natural background. A different situation develops during accidents at nuclear facilities.

So, during the explosion at the Chernobyl nuclear power plant, only about 5% of nuclear fuel was released into the environment. But this led to irradiation of many people, large areas were so contaminated that they became hazardous to health. This required the relocation of thousands of residents from the contaminated areas. An increase in radiation as a result of radioactive fallout was noted hundreds and thousands of kilometers from the accident site.

At present, the problem of storage and storage of radioactive waste from the military industry and nuclear power plants is becoming more and more acute. Every year they pose an increasing threat to the environment. Thus, the use of nuclear energy has posed new serious problems for humanity.

6. Environmental problems of the biosphere

Human economic activity, becoming more and more global in nature, begins to exert a very tangible influence on the processes taking place in the biosphere. Fortunately, up to a certain level, the biosphere is capable of self-regulation, which makes it possible to minimize the negative consequences of human activity. But there is a limit when the biosphere is no longer able to maintain balance. Irreversible processes begin, leading to environmental disasters. Humanity has already encountered them in a number of regions of the planet.

Humanity has significantly changed the course of a number of processes in the biosphere, including the biochemical cycle and migration of a number of elements. At present, albeit slowly, there is a qualitative and quantitative restructuring of the entire biosphere of the planet. A number of complex ecological problems of the biosphere have already arisen, which must be resolved in the near future.

"The greenhouse effect". The earth is growing at an alarming rate. Over the next 20-25 years, it will increase by 0.2-0.4 degrees, and by 2050 - by 2.5 degrees. Scientists associate such an increase in temperature primarily with an increase in the content of carbon dioxide (carbon dioxide) and aerosols in the atmosphere. This leads to excessive absorption of thermal radiation from the Earth by the air. A certain role in the creation of the "greenhouse effect" is played by the heat emitted from thermal power plants and nuclear power plants.

Climate warming can lead to intensive melting of glaciers and a rise in the level of the World Ocean. The changes that may result from this are simply difficult to predict.

The solution to this problem could be by reducing carbon dioxide emissions into the atmosphere and balancing the carbon cycle.

Depletion of the ozone layer. In recent years, scientists have noted with increasing concern the depletion of the ozone layer of the atmosphere, which is a protective shield against ultraviolet radiation. This process occurs especially quickly over the poles of the planet, where the so-called ozone holes have appeared. The danger is that ultraviolet radiation is harmful to living organisms.

The main reason for the depletion of the ozone layer is the use by people of chlorofluorocarbons (freons), which are widely used in production and everyday life as refrigerants, foaming agents, solvents, and aerosols. Freons intensively destroy ozone. They themselves are destroyed very slowly, within 50-200 years. In 1990. more than 1300 thousand tons of ozone-depleting substances were produced in the world.

Under the influence of ultraviolet radiation, oxygen molecules (O 2) break down into free atoms, which in turn can attach to other oxygen molecules to form ozone (O 3). Free oxygen atoms can also react with ozone molecules to form two oxygen molecules. Thus, an equilibrium is established and maintained between oxygen and ozone.

However, pollutants such as freons catalyze (accelerate) the decomposition of ozone, upsetting the equilibrium between it and oxygen in the direction of decreasing ozone concentration.

Massive deforestation is one of the most important global environmental problems of our time.

Forest communities play a critical role in the normal functioning of natural ecosystems. They absorb atmospheric pollution of anthropogenic origin, protect the soil from erosion, regulate the normal runoff of surface water, prevent a decrease in the level of groundwater and siltation of rivers, canals and reservoirs.

A decrease in forest area disrupts the process of oxygen and carbon circulation in the biosphere.

Despite the fact that the catastrophic consequences of deforestation are already widely known, their destruction continues. Currently, the total area of ​​forests on the planet is about 42 million km 2, but it is decreasing by 2% annually. Rainforests are being destroyed especially intensively in Asia, Africa, America and some other regions of the world. So, in Africa, forests used to occupy about 60% of its territory, and now - only about 17%.

Deforestation entails the death of their richest flora and fauna. Man impoverishes the appearance of his planet.

In recent years, in many countries of the world, work has begun to be successfully carried out on artificial afforestation and the organization of highly productive forest plantations.

Waste production. Waste from industrial and agricultural production has become a serious environmental problem. Attempts are currently being made to reduce the amount of waste that pollutes the environment. For this purpose, the most complex filters are being developed and installed, expensive treatment facilities and sedimentation tanks are being built. But practice shows that although they reduce the risk of pollution, they still do not solve the problem. It is known that even with the most advanced treatment, including biological, all dissolved minerals and up to 10% of organic pollutants remain in the treated wastewater. Water of this quality can only become suitable for consumption after repeated dilution with clean water.

Calculations show that 2200 km 3 of water per year are spent on all types of water use. Diluting wastewater consumes almost 20% of the world's freshwater resources. Calculations for 2012 show that even if the treatment covers all wastewater, it will still require 30-35 thousand km 3 of fresh water to dilute them. This means that the resources of the total world river flow will be close to depletion. But in many areas such resources are already in acute shortage.

Obviously, the solution to the problem is possible with the development and implementation of completely new, closed, waste-free technologies into production. When using them, the water will not be discharged, but will be reused in a closed loop. All by-products will not be thrown away as waste, but will be deeply processed. This will create conditions for obtaining additional products that a person needs and will protect the environment.

Agriculture. In agricultural production, it is important to strictly adhere to the rules of agricultural technology and monitor the rates of fertilization. Because chemical agents pest and weed control lead to significant violations of the ecological balance, a search is underway for ways to overcome this crisis in several directions.

Work is underway to develop plant varieties that are resistant to agricultural pests and diseases: bacterial and viral preparations of selective action are being created, affecting, for example, only insect pests. Ways and methods of biological control are being sought, that is, a search is underway for natural enemies that destroy harmful insects. Highly selective drugs are being developed from among hormones, antihormones and other substances capable of acting on the biochemical systems of certain insect species and not having a tangible effect on other insect species or other organisms.

Energy production. Very complex environmental problems are associated with the production of energy at thermal power plants. The need for energy is one of the basic human needs in life. Energy is needed not only for the normal functioning of a modern complexly organized human society, but also for the simple physical existence of every human organism. Currently, electricity is mainly obtained at hydroelectric power plants, thermal and nuclear power plants.

At first glance, hydroelectric power plants are environmentally friendly enterprises that do not harm nature. This was the opinion for many decades. In our country, many of the largest hydroelectric power plants have been built on great rivers. Now it became clear that this construction caused great damage to both nature and people.

· First of all, the construction of dams on large flat rivers leads to the flooding of vast territories under reservoirs. This is due to the relocation of large numbers of people and the loss of pasture land.

· Secondly, blocking off the river, the dam creates insurmountable obstacles on the migration routes of anadromous and semi-anadromous fish that ascend to spawn in the upper reaches of the rivers.

· Thirdly, the water in the reservoirs stagnates, its flow slows down, which affects the life of all living beings living in the river and near the river.

Fourth, local water rise affects groundwater, leads to flooding, waterlogging, coastal erosion and landslides.

This list of negative consequences of the construction of hydroelectric power plants on lowland rivers can be continued. Large high-rise dams on mountain rivers are also dangerous sources, especially in areas with high seismicity. In world practice, several cases are known when the breakthrough of such dams led to enormous destruction and death of hundreds and thousands of people.

From an environmental point of view, nuclear power plants (nuclear power plants) are the cleanest among other currently operating energy complexes. The danger of radioactive waste is fully recognized, therefore, both the design and operating standards of nuclear power plants provide for reliable isolation from the environment at least 99.999% of all resulting radioactive waste.

It should be borne in mind that the actual volumes of radioactive waste are relatively small. For a standard nuclear power unit with a capacity of 1 million kW, this is 3-4 m 3 per year.

Not everyone knows that coal has little natural radioactivity. Since at TPP ( thermal power plants) huge volumes of fuel are burned, then its total radioactive emissions are higher than that of a nuclear power plant. But this factor is secondary in comparison with the main disaster from the installation on fossil fuel, inflicted on nature and people - the emissions into the atmosphere of chemical compounds that are combustion products.

Although nuclear power plants are more environmentally friendly than just power plants, they pose a great potential hazard in the event of serious reactor accidents.

Conclusion

Warning about possible consequences expanding human invasion of nature, half a century ago Academician V.I. Vernadsky wrote: "Man becomes a geological force capable of changing the face of the Earth." This warning was prophetically justified. The consequences of anthropogenic activities are manifested in the depletion of natural resources, pollution of the biosphere with industrial waste, radionuclides, destruction of natural ecosystems, changes in the structure of the Earth's surface, climate change. Anthropogenic impacts lead to disruption of almost all natural biogeochemical cycles.

Due to the increase in the scale of anthropogenic impact, especially in the XX century, the balance in the biosphere is disturbed, which can lead to irreversible processes and raise the question of the possibility of life on the planet. This is due to the development of industry, energy, transport, agriculture and other human activities without taking into account the capabilities of the Earth's biosphere. Already now, humanity is faced with serious environmental problems that require immediate solutions.

List of used literature

1. Shilov I.A. Ecology - M .: Higher School, 1998.

2. Golubev G.E., Neoecology - M .: ed. Moscow State University, 1999.

3. Kriksunov E.A., Pasechnik V.V., Sidorin A.P. Ecology - M .: Publishing House "Drofa", 1995.

4. Potapov A.D. Ecology - M .: Higher School, 2003.

5. Agadzhanyan, N.A., Torshin V.I. Human ecology - M .: MMP "Ecocenter", 1994.

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South America has been developed unevenly by man. Only the marginal areas of the mainland are densely populated, mainly the coast of the Atlantic Ocean and some areas of the Andes. At the same time, the interior regions, for example, the wooded Amazonian lowland, have remained virtually undeveloped until recently.

The question of the origin of the indigenous population of South America - the Indians - has long been controversial.

The most widespread point of view is about the settlement of South America by Mongoloids from Asia through North America about 17-19 thousand years ago.

The centers of the formation of man and the ways of his resettlement across the globe (according to V.P. Alekseev): 1 - the ancestral home of mankind and resettlement from it; 2 - primary western focus of race formation and dispersal of proto-Australoids; 3 - resettlement of protoevropoids; 4 - resettlement of protonegroids; 5 - primary eastern focus of race formation and dispersal of protoamericanoids; 6 - North American Tertiary focus and dispersal from it; 7 - Central South American focus and dispersal from it.

But, based on some anthropological commonality of the Indian peoples of South America with the peoples of Oceania (wide nose, wavy hair) and on the availability of the same tools of labor, some scientists expressed the idea of ​​settling South America from the Pacific Islands. However, this point of view is shared by few. Most scientists are inclined to explain the presence of Oceanian features among the inhabitants of South America by the fact that representatives of the Oceanic race could have penetrated through the northeast of Asia and North America with the Mongoloids.

At present, the number of Indians in South America is much higher than in North America, although during the period of colonization of the continent by Europeans, it has greatly decreased. In some countries, Indians still make up a significant percentage of the population. In Peru, Ecuador and Bolivia, they are about half of the total number, and in some areas they even significantly predominate. Most of the population of Paraguay is of Indian origin, many Indians live in Colombia. In Argentina, Uruguay, Chile, the Indians were almost completely exterminated in the first period of colonization, and now there are very few of them. Brazil's Indian population is also steadily declining.

In the interior regions of Brazil, there are still the remnants of tribes of the language family "same". By the time the Europeans arrived on the mainland, they inhabited the eastern and southern parts of Brazil, but were pushed aside by the colonialists into forests and swamps. This people is still at a level of development corresponding to the primitive communal system, and is distinguished by a wandering way of life.

The inhabitants of the extreme south of South America (Tierra del Fuego) were at a very low stage of development before the arrival of Europeans. They protected themselves from the cold with animal skins, weapons were made of bone and stone, food was obtained by hunting guanacos and sea fishing. Fire-earthers were subjected to the most severe physical extermination in the 19th century, now there are very few of them.

At a higher level of development were the tribes inhabiting the central and northern parts of the continent in the Orinoco and Amazon basins (peoples of the Tupi Guarani, Arawak, Caribbean language families). They are still engaged in agriculture, cultivating cassava, corn, cotton. They hunt using bows and arrow-throwing tubes, and also use the instantly acting plant poison curare.

Before the arrival of Europeans, the main occupation of the tribes living in the Argentine Pampa and Patagonia was hunting. The Spaniards brought horses to the mainland, which subsequently ran wild. The Indians learned to tame horses and began to use them to hunt guanacos. The rapid development of capitalism in Europe was accompanied by the ruthless extermination of the population of the colonial lands. In Argentina, in particular, the local residents were pushed back by the Spaniards to the extreme south of Patagonia, to lands unsuitable for grain farming. Currently, in Pampa, the indigenous population is almost completely absent. Only small groups of Indians have survived, working as laborers on large agricultural farms.

The highest socio-economic and cultural development before the arrival of Europeans was reached by the tribes inhabiting the high plateaus of the Andes within Peru, Bolivia and Ecuador, where one of the most ancient centers of irrigated agriculture is located.

An Indian tribe, a Quechua language family that lived in the XI-XIII centuries. on the territory of modern Peru, united the scattered small peoples of the Andes and formed a strong state, Tahuantinsuyu (XV century). The leaders were called "Inca". Hence the name of the whole people came from. The Incas subjugated the Andean peoples up to the modern territory of Chile, spread their influence also to the more southern regions, where an independent, but close to the Inca culture of the sedentary farmers of the Araucans (Mapuche) arose.

Irrigated agriculture was the main occupation of the Incas, and they cultivated up to 40 species of cultivated plants, placing fields in terraces along the slopes of the mountains and bringing the water of mountain streams to them. The Incas tamed wild llamas, using them as beasts of burden, and bred domestic llamas, from which they received milk, meat, wool. The Incas were also famous for their ability to build mountain roads and bridges from vines. They knew many crafts: pottery, weaving, processing of gold and copper, etc. From gold they made jewelry and religious objects. In the Inca state, private land ownership was combined with collective land ownership; the state was headed by a supreme leader with unlimited power. From the conquered tribes, the Incas collected taxes. The Incas are the creators of one of the oldest civilizations in South America. Some monuments of their culture have survived to this day: ancient tracts, the remains of architectural structures and irrigation systems.

Individual peoples that were part of the Inca state still inhabit the desert high plateaus of the Andes. They cultivate the land in a primitive way, cultivating potatoes, quinoa and some other plants.

The most numerous modern Indian people - Quechua - inhabit the mountainous regions of Peru, Bolivia, Ecuador, Chile and Argentina. On the shores of Lake Titicaca live Aymara - one of the most mountainous peoples in the world.

The core of the indigenous population of Chile was a group of strong agricultural tribes, united under the common name of the Araucanians. They put up a long resistance to the Spaniards, and only in the 18th century. some of them, under the onslaught of the colonialists, moved to Pampa. Now the Araucans (Mapuche) live in the southern half of Chile, only a few of them - in the Argentine Pampa.

In the north of the Andes, on the territory of modern Colombia, by the arrival of the Spanish conquerors, a cultural state of the Chibcha-Muisca peoples was formed. Now small tribes - the descendants of the Chibcha, who have preserved remnants of the tribal system, live in Colombia and the Isthmus of Panama.

The first settlers from Europe to come to America without families married Indian women. As a result, a mixed, mestizo population was formed. The crossbreeding process continued later.

Currently, "pure" representatives of the Caucasian race are almost completely absent on the mainland. The only exceptions are later immigrants. Most of the so-called "whites" contain, to one degree or another, an admixture of Indian (or Negro) blood. This mixed population (mestizo, cholo) predominates in almost all South American countries.

A significant part of the population, especially in the Atlantic regions (in Brazil, Guiana, Suriname, Guyana), are Negroes - the descendants of slaves brought to South America at the beginning of colonization, when they needed a large and cheap labor force used on plantations. Blacks partially mingled with white and Indian populations. As a result, mixed types were created: in the first case - mulattos, in the second - sambo.

Fleeing from exploitation, negro slaves fled from their masters to the rainforests. Their descendants, some of whom mixed with the Indians, still lead a primitive forest lifestyle in some areas.

Before the declaration of independence of the South American republics, i.e. until the first half of the 19th century, immigration to South America from other countries was prohibited. But subsequently, the governments of the newly formed republics, interested in the economic development of their states, the development of vacant lands, opened access to immigrants from different countries of Europe and Asia. Especially many citizens arrived from Italy, Germany, the Balkan countries, partly from Russia, China and Japan. Settlers over late period usually keep apart, retaining their language, customs, culture and religion. In some republics (Brazil, Argentina, Uruguay), they form significant groups of the population.

The peculiarities of the history of South America and, as a consequence, the great unevenness in the distribution of the modern population and its relatively low average density have led to a significant preservation of natural conditions in comparison with other continents. Large areas of the Amazonian lowland, the central part of the Guiana Highlands (Roraima Massif), the southwestern Andes and the Pacific coast remained undeveloped for a long time. Separate roving tribes in the Amazonian forests, almost not in contact with the rest of the population, not so much influenced nature as they themselves depended on it. However, such areas are becoming less and less. The extraction of minerals, the laying of communication lines, in particular the construction of the Trans-Amazonian Railway, the development of new lands, leave less and less space in South America that is not affected by human activities.

Extraction of oil in the very thick of the Amazon rainforest or of iron and other ores within the Guiana and Brazilian highlands required the construction of transport routes in the recently still remote and inaccessible areas. This, in turn, led to an increase in population, destruction of forests, expansion of arable and pasture lands. As a result of an attack on nature using the latest technology, the ecological balance is often disturbed, and easily vulnerable natural complexes are destroyed.

The development and significant transformations began primarily from the La Plata plain, the coastal parts of the Brazilian Highlands, the extreme north of the mainland. The areas that were developed even before the beginning of European colonization are located in the depths of the Andes of Bolivia, Peru and other countries. On the territory of the most ancient Indian civilizations, centuries of human activity have left their mark on the desert plateaus and mountain slopes at an altitude of 3-4.5 thousand meters above sea level.

Now the population of South America is almost 320 million people, with 78% being urban. The growth of large cities is causing serious environmental problems in urban areas around the world. This is a shortage and low quality of drinking water, air pollution, accumulation of solid waste, etc.

MINISTRY OF EDUCATION AND SCIENCE OF THE RF STATE EDUCATIONAL INSTITUTION OF HIGHER PROFESSIONAL EDUCATION BASHKIR STATE UNIVERSITY FACULTY OF GEOGRAPHY

Department "Physical Geography"

COURSE WORK

in the discipline "Physical geography of continents and oceans"

on the topic: "Geographic zones and natural areas South America "

Introduction

CHAPTER 1. NATURAL ZONES OF THE EQUATORIAL AND SUB-EQUATORIAL BELTS

1.1 Zone of humid equatorial forests

1.2 Subequatorial forest zone

1.3 Zone of savannas, woodlands and shrubs

CHAPTER 2. NATURAL ZONES OF TROPICAL, SUBTROPICAL AND MODERATE BELTS

2.1 Rainforest zone

2.2 Zone of savannas, woodlands and shrubs

2.3 Zone of tropical semi-deserts and deserts

2.4 Zone of subtropical mixed forests

2.5 Pampa or subtropical steppe

2.6 Zone of dry hard-leaved Mediterranean forests

2.7 Zone of semi-desert of the temperate zone

2.8 Subantarctic forests

CHAPTER 3. MAN: SETTLEMENT AND INFLUENCE ON THE NATURE OF SOUTH AMERICA

3.1 Human settlement in South America

3.2 Human Impact on the South American Environment

CONCLUSION

LIST OF USED LITERATURE

INTRODUCTION

South America is a continent crossed by the equator, most of which is located in the Southern Hemisphere. South America is located between the Pacific Ocean and the Atlantic Ocean. It was connected to North America quite recently with the formation of the Isthmus of Panama. The Andes, a relatively young and seismically unstable mountain range, stretches along the western edge of the continent; the land to the east of the Andes is occupied mainly by tropical forests, the vast basin of the Amazon River. The largest country in South America in terms of area and population is Brazil. Regions of South America include the Andean states, the Guyana Highlands, the Southern Cone, and Eastern South America. South America also includes various islands, most of which belong to the countries of the continent. The Caribbean territories belong to North America. Countries in South America that border Caribbean- including Colombia, Venezuela, Guyana, Suriname and French Guiana - known as Caribbean South America. term paper we will consider the natural zones and geographic zones of South America, as well as human settlement and its impact on the nature of South America.

CHAPTER 1. NATURAL ZONES OF THE EQUATORIAL AND SUB-EQUATORIAL BELTS

1.1 Zone of humid equatorial forests

Wet equatorial forests - evergreen forests, mainly in the equatorial, less often in the subequatorial zones in the north of South America, in Central America, in Western Equatorial Africa, in the Indo-Malay region. In the Amazon basin, they are called helium, selva. Distributed in areas with annual precipitation of more than 1500 mm, relatively evenly distributed over the seasons. A wide variety of tree species is characteristic: from 40 to 170 species are found per hectare. Most trees have straight, columnar trunks, branching only in the upper part. The tallest trees reach heights. 50-60 m, trees avg. tier - 20-30 m, lower - approx. 10 m. Many trees have board-like roots, sometimes rising to a height. 8 m. In swampy forests, trees have stilted roots. The change of foliage in different types of trees occurs in different ways: some shed their leaves gradually throughout the year, others only at certain periods. Opening young leaves initially hang as withered, sharply differing in color, which is characterized by a wide range of colors - from white and pale green to crimson and burgundy. Flowering and fruiting also occur unequally: continuously throughout the year or periodically - once or several times a year. Often on the same tree you can see branches with fruits, flowers and young leaves. Many trees are characterized by caulifloria - the formation of flowers and inflorescences on the trunks and leafless areas of the branches. The dense crowns of trees almost do not allow sunlight to pass through, so there are very few grasses and shrubs under their canopy. In the equatorial forests there are many vines, mainly with woody stems, less often grassy ones. Their trunks reach a diameter of 20 cm, and the leaves are raised to the height of tree crowns. Some lianas, for example, rattan palms, rest on tree trunks with short shoots or special outgrowths; others, such as vanilla, are fixed with adventitious roots; however, most tropical vines are curly. There are often cases when the trunk of a vine is so strong, and the crown is so closely intertwined with several trees that the tree braided by it does not fall after death. Epiphytes are very diverse and numerous - plants growing on trunks, branches, and epiphylls - on tree leaves. They do not suck out nutritious juices from the host plant, but use it only as a support for growth. Epiphytes from the bromeliad family accumulate water in the rosettes of leaves. Orchids store nutrients in thickened areas of shoots, roots or leaves. Breeding epiphytes, for example. ferns "bird's nest" and "antlers" accumulate soil between the roots, epiphytes-sconces - under the leaves adjacent to the tree trunks. In America, even some types of cacti are epiphytes. Wet equatorial forests have been predatory and continue to be destroyed. By now, their area has already halved and continues to decrease at a rate of 1.25% per year. They are inhabited by St. 2/3 of all species of plants and animals on Earth, many of which perish, even without being discovered and explored by man. In place of the destroyed primeval forest, low-growing and very species-poor forests of fast-growing trees begin to grow. With regular fires and clearings, secondary forests are replaced by savannas or pure thickets of cereals.

1.2 Subequatorial forest zone

The subequatorial forest zone is located on the outskirts of the equatorial belt. Subequatorial forests in the inner regions of the subequatorial belt, in the outer - savannahs. Subequatorial forests are divided into 2 late ones: 1. Seasonally humid forests. Dry season 3.5-4 months, ferralite soils. The main background of forests in the north of the Guiana Highlands. 2. Subzone of permanently humid subequatorial forests. Occupies only the North-East of the Guiana Plateau. Dry season less than two months. The soils are ferralite and red-yellow.

1.3 Zone of savannas, woodlands and shrubs

Zones of savannas, woodlands and shrubs are located mainly in the subequatorial and partly in the tropical climatic zones. The savannahs occupy the Orinoco Plain, where they are called llanos, as well as the interior of the Guiana and Brazilian Highlands (campos).

Savannah soils are red ferralite and red-brown. In the savannahs of the northern hemisphere, sparsely standing palms and acacias grow among tall grasses. Gallery forests are characteristic along the river banks. In the savannas of the Brazilian Highlands, the grass cover, as in the llanos, consists of tall grasses and legumes. But the woody vegetation is much poorer; mimosas, tree-like cacti, and milkweed predominate. In the northeast of the Brazilian Highlands and the Inner Tropical Plains, in a drier climate (up to 400 mm of precipitation per year), tough grasses, thorny shrubs, bottle trees, low-growing open forests of kebracho - a tree with very hard wood (“kebracho” in translated means "break the ax"). In the fauna of the savannahs of South America, there are few ungulates (small deer); there are peccary pigs, armadillos, anteaters, and of the predators - the cougar. Subzones: 1. Wet savannahs. Orinok lowland (llanos). A clear division into a dry period, 3.5-4 months. The soils are red, there are areas of yellow and red-yellow. Palm vegetation and herbs. 2. Dry shrub savannas and woodlands. Central part of the Brazilian Highlands, North-East of the Orinoco Plain. The amount of precipitation is not more than 700 mm, the soils are brown-red. The grass cover is sparse, represented mainly by grasses, shrubs are characteristic. This type of savanna is called campos. Dry period about 5 months 3. Kaatina (subzone of deserted woodland). North-East of the Brazilian Highlands. Almost complete absence of grass cover, only shrubs and a wax palm grow. The soils are red-brown.

CHAPTER 2. NATURAL ZONES OF TROPICAL, SUBTROPICAL AND MODERATE BELTS

2.1 Rainforest zone

Stretches along the entire eastern, windward slope of the Brazilian Highlands, receives 1500-2000 mm of precipitation per year thanks to the southeastern trade winds. The close proximity of the ocean leads to an equal maritime climate with temperatures of + 20 ... + 24 in winter and + 26 ... + 27 in summer. Therefore, the vegetation is represented by dense multi-tiered evergreen forests, close to the mountain equatorial forests. In these forests there are many types of trees with valuable wood: pau-Brasil tree, rosewood tree, rosewood tree, purple tree, zebra tree, ebony, etc. There are many palms and ferns. The soils of the zone are typical - red-yellow ferralite. Divided into two subzones (east of the Brazilian Highlands): 1. Subzone of seasonally moist forests (in the north). Precipitation is not more than 1400 mm, dry period is about 5 months. 2. Subzone of permanently humid (trade wind) forests.

Towards the west, the tropical belt narrows.

2.2 Zone of savannas, woodlands and shrubs

Distributed in the Gran Chaco plain. The climate of the zone is similar to the subequatorial one, but differs from it in a significant continentality and large amplitudes of seasonal temperatures. It is here that the "pole of heat" of South America is located - + 47 C. The duration of the dry period is 9-10 months, which causes the complete drying up of water bodies in winter. The soils are brown-red and even red-brown. The vegetation cover is dominated by dry woodlands, represented by gnarled Kebracho, Algarrobo, Chanyar trees with an admixture of succulents. The fauna is very poor, similar in species composition to the fauna of the savannas of the subequatorial belt. As the climate changes, that is, with the advent of the dry season, tropical rainforests in South America pass into savannas and tropical woodlands. In the Brazilian Highlands, between savannas and tropical rainforest, there is a strip of almost pure palm forests. Savannahs are distributed over a large part of the Brazilian Highlands, mainly in its hinterland. In addition, they occupy large areas in the Orinoco Lowland and in the central regions of the Guiana Highlands. In Brazil, the typical savannas on red ferralite soils are known as campos. Their herbaceous vegetation consists of tall grasses of the genera Paspalum, Andropogon, Aristida, as well as representatives of the legume and Asteraceae families. Woody forms of vegetation are either completely absent, or are found in the form of individual specimens of mimosa with an umbrella-shaped crown, tree-like cacti, milkweed and other xerophytes and succulents. In the dry northeast of the Brazilian Highlands, a significant area is occupied by the so-called caatinga, which is a sparse forest of drought-resistant trees and shrubs on red-brown soils. Many of them lose their leaves during the dry season, others have a swollen trunk in which moisture accumulates, for example, a willow tree (Cavanillesia platanifolia). The trunks and branches of caatinga trees are often covered with vines and epiphytic plants. There are also several types of palm trees. The most remarkable tree of the caatinga is the waxy carnauba palm (Copernicia prunifera), which gives plant wax that is scraped off or boiled out of its large (up to 2 m long) leaves. Wax is used for making candles, scrubbing floors and other purposes. From the upper part of the trunk of carnauba, sago and palm flour are obtained, the leaves are used to cover roofs and weaving various products, the roots are used in medicine, and the local population uses the fruits for food in raw and boiled form. It is not for nothing that the inhabitants of Brazil call carnauba the tree of life. On the plain of Gran Chaco, in especially arid regions, on brown-red soils, thickets of thorny bushes and sparse forests are common. In their composition, two species belong to different families, they are known under the general name "kebracho" ("break the ax"). These trees contain a large amount of tannins: red kebracho (Schinopsis Lorentzii) - up to 25%, white kebracho (Aspidosperma quebracho blanco) - slightly less. Their wood is heavy, dense, does not rot and sinks in water. The kebracho is strenuously cut down. At special factories, tanning extract is obtained from it, sleepers, piles and other items are made from wood, intended for a long stay in water. Algarrobo (Prosopis juliflora) is also found in the forests - a tree from the mimosa family with a curved trunk and a highly branching spreading crown. The fine, delicate foliage of the algarrobo does not give shade. Low tiers of forest are often represented by thorny shrubs that form impenetrable thickets. Savannahs of the northern hemisphere differ from southern savannas in appearance and species composition of flora. To the south of the equator, palms grow among thickets of grasses and dicotyledons: copernicia (Copernicia spp.) - in drier places, meandering mauritia (Mauritia flexuosa) - on swampy or river-flooded areas. The wood of these palms is used as a building material, the leaves are used for weaving of various products, the fruits and the core of the trunk of mauritia are edible. There are also numerous acacias and tall tree-like cacti. Red and red-brown soils of savannas and tropical woodlands are distinguished by a higher humus content and greater fertility than soils of moist forests. Therefore, in the areas of their distribution, there are the main areas of plowed land with plantations of coffee trees, cotton, bananas and other cultivated plants exported from Africa. The fauna of drier and more open spaces of South America - savannas, tropical woodlands, subtropical steppes - is different than in dense forests. Among the predators, apart from the jaguar, the puma (found almost throughout South America and entering North America), the ocelot, and the pampa cat are widespread. A maned wolf from the canine family is characteristic of the southern part of the mainland. On the plains and in mountainous regions, the pampa fox is found almost throughout the mainland, in the extreme south - the Magellanic fox. Of the ungulates, the small Pampas deer is widespread. In savannas, forests and arable lands, representatives of the third American family of edentulous are found - armadillos (Dasypodidae) - animals equipped with a strong bony shell. As danger approaches, they burrow into the ground. Of the rodents in the savannas and steppes, there are viscacha and tukotuko living in the land. The marsh beaver, or nutria, is widespread along the shores of water bodies, whose fur is highly valued in the world market.

Among birds, in addition to numerous parrots and hummingbirds, rhea (genus Rhea) also live - South American representatives of the order of ostrich-like, some large birds of prey. There are many snakes and lizards in savannas and steppes. A characteristic feature of the landscapes of South America is a large number of termite mounds. Parts of South America are periodically affected by locust infestations.

2.3 Zone of tropical semi-deserts and deserts

Deserts and semi-deserts - a natural area characterized by a complete absence of vegetation and a very poor wildlife. All this is due to the extremely harsh climatic conditions of the planet where they are located. Deserts, in principle, can form in any climatic zone. Their formation is primarily associated with low precipitation. That is why deserts are primarily common in the tropics. Tropical deserts occupy the western coast of the tropical belt of South America. The natural conditions of the deserts are extremely harsh. The amount of precipitation here does not exceed 250 mm per year, and in large areas it is less than 100 mm. Daily temperature ranges reach 30 ° С, very dry winds are constant. All this creates favorable conditions for intense physical weathering and deflation, accumulation of clastic material strata, in which temporary streams dry up. The annual runoff does not exceed 50 mm; there is no runoff to the ocean. Salt lakes and salt marshes are widespread in depressions. On barely developed gravelly or sandy soils, a very sparse "cover" of desert vegetation, also called puna, of creeping or pillow-like herbaceous and shrubs is characteristic. The driest desert in the world is the Atacama Desert, where there has been no rainfall for 400 years. The fauna, except for birds, is also poor. In the less severe northern and eastern regions, steppes appear on ancient alluvial soils, and agriculture is possible up to an altitude of 4200 m. Mules and especially llamas are also bred here. Coastal deserts and semi-deserts in the west of the tropical belt of South America are unusually stretched in latitude: from 5 to 28 ° S. sh. along the coast and along the western slopes of the Andes. To all their inherent features (low coastal temperatures, waterlessness, intense physical weathering, buried decrepit relief, isolated representatives of xerophytic-succulent vegetation and desert fauna) in South America, a special coastal type of vegetation is added - scrap (plural lomas), vegetating during development of heavy fog and drizzle.

2.4 Zone of subtropical mixed forests

To the east of the Andes, not only does the amount of precipitation increase (from 400-500 mm / year in dry steppes to 1000-1200 mm in wet steppes), but also their distribution over the seasons is leveled - in the east, they fall throughout the year. Accordingly, gray-brown soils in the subzone of dry steppes are replaced by chernozem-like and reddish-black soils in humid steppes and subtropical savannas. These are areas of intensive agriculture (sowing of grain, forage grasses, flax for seed, etc.) and cattle breeding. Natural vegetation is almost not preserved, and the soil cover is subject to severe erosion. Despite the abundant rainfall, the river network in Pampa is poorly developed and the surface runoff is small. The position and nature of the eastern oceanic zone of subtropical mixed forests are very peculiar in South America. It is expressed on the high lava plateau of Parana between 24-30 ° S. sh., that is, in lower latitudes than on other continents. The gentle slope of the Brazilian Highlands to the south allows deep incursions of winter cold winds from Pampa - pamporos, causing temperatures to drop to -6 ° C. Average temperatures in July 12, 13 ° C. Due to the limited land area, there is no winter continental monsoon in this area (as in Pampa), frontal rains occur in winter.

2.5 Pampa or subtropical steppe

Pampa is a steppe of the subtropical zone of South America. Here, warm winters and rarely frosts, little rainfall, only up to 500 mm per year. There are no trees in these steppes due to repeated dry periods and highly dense clayey soils. Grains suffer less from grazing and fires. Trees are found only on the slopes of the terraces along the river valleys. A characteristic feature of pampas is the presence of closed lakes, many of which dry up in summer. The water in them is alkaline, as soda accumulates in them. Today, the pampa is densely populated; the bulk of the inhabitants of Argentina live here. Livestock raising and agriculture are well developed. The soil is plowed up and the native vegetation is almost not preserved, and there are no reserves. You can find some indigenous vegetation in the alienated areas along the banks of rivers, roads and railways. The landscape of the pampas has changed, alternating arable land (corn, wheat), seeded pastures and strips of exotic trees. The former richest flora had about 1000 species of cereals and the same amount of forbs. In this huge green sea, the rider could easily hide. Mainly cereals prevailed: pearl barley, bonfire, bearded vulture, feather grass, bluegrass, and in the south there are tuyeski. Also, the animal world was rich, there were many species of rodents; to this day, only one representative of the epidemic of the South American family Viscachi has survived. Most of the animals and birds are on the verge of extinction, for example, the Pampian deer. Argentine Pampa - a flat desert area stretches from the Atlantic Ocean to the foothills of the Andes, from the La Plata River to the Rio Negro. "Pampa" is a plain, translated from the language of the Quechua Indians. The landscape is deserted and sometimes monotonous, as if mountains rise out of nowhere in front of the traveler, like an island in the middle of the sea. The pampa covers about 80 thousand square kilometers of territory, such a long length of the pampa arose as a result of the accumulation of loose rocks, destroyed rocks of the Andes. The rivers brought into the pampa by mountain streams and the wind played a role in driving here small particles of destroyed rocks. Thick sedimentary strata of up to 300 m are located near Buenos Aires, and in some places they completely cover the ancient forms of relief. There are no slopes, thereby making it difficult to drain water, thus, the pampa was formed due to the gigantic forces of nature itself, which sculpted the relief and many times redone the work of its creation. Today, the Argentine Pampa is similar to the Indus-Gangetic Plain, but the natural conditions of South Asia are different from Argentina. There are no slopes and no rainwater slides down or rivers form. Rainwater accumulates on clayey areas in depressions and forms Lagunas - swamp lakes. Most of the rivers originate in the Pampian Sierras, but the further they go into the valley they lose their strength and most of them dry up. They often change the course of the river, leaving flood waters behind, which eventually become swampy. The difference in climate between the eastern and western parts explains the difference in the composition of their soils. In the western part, there is a hot arid climate with low vegetation, most of the land is completely bare. Eastern with a lot of precipitation - dense vegetation.

2.6 Zone of dry, hard-leaved Mediterranean forests

In the subtropical zone in the west of the mainland between 32-38 ° S, w. (central part of central Chile), as in all other continents, there is a zone of dry hard-leaved Mediterranean forests and shrubs, the transition to which from tropical semi-deserts occurs through subtropical semi-deserts (28-32 ° S). Cordillera, where brown soils and maquis-like thickets of stiff-leaved shrubs are common. Through the arid Central Valley, a zone of subtropical shrub steppes with brown soils penetrates to the south. On the Main Cordillera, the spectrum of high-altitude zones, characteristic of the Mediterranean zone, is expressed. Below there are stiff-leaved shrubs, in the middle zone there are evergreen deciduous forests with an admixture of conifers, in the upper zone there are mountain steppes, in the more humid south alpine meadows appear. Since precipitation falls mainly in winter, and summer is rainless, the regime of rivers is uneven, floods occur in winter and in spring. summer time when snow and glaciers melt in the mountains. In the relief, along with water-erosional forms towards the south, glacial ones play an increasing role. The river valleys in the mountains and the Central Valley are the most important agricultural areas in Chile.

2.7 Zone of semi-desert of the temperate zone

In the extreme south of the continent, in the temperate zone, a natural zone of semi-deserts and deserts, which is not very typical for these latitudes, has formed. It is the only desert and semi-desert zone in the world that overlooks the ocean coastline within the temperate zone. Under conditions of insignificant amount of precipitation (about 200 mm per year), cereals, cacti and cushion-like shrubs grow on gray earth and brown soils. The fauna is poor, only rodents and reptiles are numerous. Coastal deserts and semi-deserts extend in a narrow strip (from 5 degrees to 28 degrees S) and on the western coast of South America. The proximity of the ocean is the reason for the high humidity here, the coast is shrouded in fog for a significant part of the year, and there is little rainfall. It happens that it does not rain for 10 - 20 years. The reason for this is not only the prevailing air masses, but also the cold Peruvian current. The driest part of the natural area is the coastal Atacama Desert. On its predominantly sandy surface, occasionally there are single drought-resistant plants, in particular cacti. The Atacama rises along the slopes of the Andes up to 3000 m, where it turns into a high-mountainous desert. To the south of the coastal deserts on the western coast of the mainland and the island of Tierra del Fuego, there are temperate forests, where conifers appear: Chilean cedars, cypresses and araucaria.

2.8 Subantarctic forests

The slopes of the Patagonian Andes are covered with moisture-loving subantarctic forests, consisting of tall trees and shrubs, among which evergreen species predominate: at 42 S lat. there is an array of araucaria forests, and mixed forests are spread to the south. Due to their density, abundance of species, multilevel, variety of lianas, mosses and lichens, they resemble forests of low latitudes. The soils under them are of the brown soil type, in the south - podzolic. There are many swamps in flat areas. The main representatives of the flora of the forests of the Southern Andes are the evergreen and deciduous species of southern beeches, magnolias, giant conifers of the genus Fitroja and hiocetruses, bamboos and tree ferns. Many plants have beautiful, fragrant flowers, especially in the forest in spring and summer. The branches and trunks of trees are entangled with lianas and are covered with lush moss and lichen cover. Mosses and lichens, along with leaf decay, cover the surface. With the rise in the mountains, forests are thinned and their species composition becomes impoverished. In the extreme south, they are gradually replaced by tundra vegetation. On the eastern slope of the mountains, facing the Patanon plateau, precipitation falls much less than in the west. Forests are less dense, poorer in species composition compared to the Pacific coast. The main forest-forming species are southern beeches with an admixture of some conifers. At the foot of the mountains, forests turn into dry steppes and shrubs of the Patagonian plateau.

CHAPTER 3. MAN: SETTLEMENT AND INFLUENCE ON THE NATURE OF SOUTH AMERICA

3.1 Human settlement in South America

equatorial forest savanna wednesday

South America has been developed unevenly by man. Only the marginal areas of the mainland are densely populated, mainly the coast of the Atlantic Ocean and some areas of the Andes. At the same time, the interior regions, such as the wooded Amazonian lowland, have remained virtually unexploited until recently. The question of the origin of the indigenous population of South America - the Indians - has long been controversial. The most common point of view is that Mongoloids from Asia through North America settled South America about 17-19 thousand years ago (Appendix 1). But, based on some anthropological commonality of the Indian peoples of South America with the peoples of Oceania and on the availability of the same tools of labor, some scientists have suggested the settlement of South America from the Pacific Islands. However, this point of view is shared by few. Most scientists tend to explain the presence of Oceanian features among the inhabitants of South America by the fact that representatives of the Oceanic race could also penetrate through the northeast of Asia and North America with the Mongoloids. At present, the number of Indians in South America is much higher than in North America, although during the period of colonization of the continent by Europeans, it has greatly decreased. In some countries, Indians still make up a significant percentage of the population. In Peru, Ecuador and Bolivia, they are about half of the total number, and in some areas they even significantly predominate. Most of the population of Paraguay is of Indian origin, many Indians live in Colombia. In Argentina, Uruguay, Chile, the Indians were almost completely exterminated in the first period of colonization, and now there are very few of them. The population of Brazil is also steadily declining. In the Andes and on the Pacific coast, strong Indian states developed, characterized by a high level of development of agriculture and cattle breeding, crafts, applied arts and the rudiments of scientific knowledge. The agricultural peoples of South America gave such cultivated plants as potatoes, cassava, peanuts, and pumpkin. In the process of European colonization and a fierce struggle against the colonialists, some Indian peoples completely disappeared from the face of the Earth, others were pushed back from their ancestral territories to uninhabited and inconvenient lands. Individual Indian peoples continue to live in areas of their former habitat. Until now, there are tribes living in isolation, retaining the level of development and way of life at which they were found by the invasion of Europeans. In the interior regions of Brazil, there are still the remnants of tribes of the language family "same". By the time the Europeans arrived on the mainland, they inhabited the eastern and southern parts of Brazil, but were pushed aside by the colonialists into forests and swamps. This people is still at a level of development corresponding to the primitive communal system, and is distinguished by a wandering way of life. The inhabitants of the extreme south of South America (Tierra del Fuego) were at a very low stage of development before the arrival of Europeans. They protected themselves from the cold with animal skins, made weapons from bone and stone, and obtained food by hunting the gunako and sea fishing. Fire-earths underwent severe physical extermination in the 19th century, now there are very few of them. Before the arrival of Europeans, the main occupation of the tribes living in the Argentine Pampa and Patagonia was hunting. The Spaniards brought horses to the mainland, which subsequently ran wild. The Indians learned how to tame horses and began to use them to hunt gunakos. The rapid development of capitalism in Europe was accompanied by the ruthless extermination of the population of the colonial lands. In Argentina, in particular, the Spaniards pushed the local residents to the extreme south of Patagonia, to lands unsuitable for grain farming. Currently, in Pampa, the indigenous population is almost completely absent. Only small groups of Indians have survived, working as laborers on large agricultural farms. The highest socio-economic and cultural development before the arrival of Europeans was reached by the tribes inhabiting the high plateaus of the Andes within Peru, Bolivia and Ecuador, where one of the most ancient centers of irrigated agriculture is located. The most numerous modern Indian people - Quechua - inhabit the mountainous regions of Peru, Bolivia, Ecuador, Chile and Argentina. On the shores of Lake Titicaca live Aymara - one of the most mountainous peoples in the world. A significant part of the population, especially in the Atlantic regions (in Brazil, Guiana, Suriname, Guyana), are Negroes - the descendants of slaves brought to South America at the beginning of colonization, when they needed a large and cheap labor force used on plantations. Blacks partially mingled in white and Indian populations. As a result, mixed types were created: in the first case - mulattos, in the second - sambo. Fleeing from exploitation, negros - slaves fled from their masters to the tropical forests. Their descendants, some of whom mixed with the Indians, in some areas still lead a primitive forest lifestyle. Before the declaration of independence of the South American republics, that is, until the first half of the 19th century, immigration to South America from other countries was prohibited. But subsequently, the governments of the newly formed republics, interested in the economic development of their states, the development of vacant lands, opened access to immigrants from different countries of Europe and Asia. Especially many citizens arrived from Italy, Germany, the Balkan countries, partly from Russia, China and Japan. The settlers of the later period usually keep apart, retaining their language, customs, culture and religion. In some republics (Brazil, Argentina, Uruguay), they form significant groups of the population.

3.2 Human Impact on the South American Environment

The peculiarities of the history of South America and, as a consequence, the great unevenness in the distribution of the modern population and its relatively low average density have led to a significant preservation of natural conditions in comparison with other continents. Large areas of the Amazonian lowland, the central part of the Guiana Highlands (Roraima Massif), the southwestern Andes and the Pacific coast remained undeveloped for a long time. Individual wandering tribes in the Amazonian forests, almost not in contact with the rest of the population, did not so much influence nature as they themselves depended on it. However, such areas are becoming less and less. The extraction of minerals, the laying of communication routes, in particular the construction of the Trans-Amazonian highway, the development of new lands, leave less and less space in South America that is not affected by human activities. Extraction of oil in the thickest of the Amazon rainforest or of iron and other ores within the Guiana and Brazilian highlands required the construction of transport routes in the recently still remote and inaccessible areas. This, in turn, led to an increase in population, destruction of forests, expansion of arable and pasture lands. As a result, with the use of the latest technology, the ecological balance is often disturbed in nature, vulnerable natural complexes are destroyed (Appendix 2). The development and significant transformations began primarily from the La Plata plain, the coastal parts of the Brazilian Highlands, the extreme north of the mainland. The areas that were developed even before the beginning of European colonization are located in the depths of the Andes of Bolivia, Peru and other countries. On the territory of the most ancient Indian civilizations, centuries of human activity have left their mark on the desert plateaus and mountain slopes at an altitude of 3-4.5 thousand meters above sea level. Now the population of South America is almost 320 million people, with 78% being urban. The growth of large cities is causing serious environmental problems in urban areas around the world. This is a shortage and low quality of drinking water, air pollution, accumulation of solid waste, etc.

CONCLUSION

South America has been developed unevenly by man. Only the marginal areas of the mainland are densely populated, mainly the coast of the Atlantic Ocean and some areas of the Andes. At the same time, hinterland areas, such as the wooded Amazonian Lowland, have remained virtually undeveloped until recently. Extraction of oil in the thickest of the Amazon rainforest or iron and other ores within the Guiana and Brazilian highlands required the construction of transport routes in the recently still remote and inaccessible areas. ... This, in turn, led to an increase in population, destruction of forests, expansion of arable and pasture lands. As a result, with the use of the latest technology in nature, the ecological balance is often disturbed, vulnerable natural complexes are destroyed. The growth of large cities is causing serious environmental problems in urban areas around the world. This is a shortage and low quality of drinking water, air pollution, accumulation of solid waste, etc.

LIST OF USED LITERATURE

1. Arshinova M.A., Vlasova T.V., Kovaleva T.A. Physical geography of continents and oceans. - M .: Academy, 2005 .-- 636 p.

2. Vlasova T.V. Physical geography of the parts of the world / 2nd edition, revised and enlarged. - M .: Education, 1966 .-- 640 p.

3. Galai I.P., Zhuchkevich V.A., Rylyuk G.Ya. Physical geography of continents and oceans. Part 2. - Minsk: Universitetskoe Publishing House, 1988 .-- 357 p.

4. Zhuchkevich V.I., Lavrinovich M.V. Physical geography of continents and oceans. Part 1. - Minsk: Universitetskoe Publishing House, 1986 .-- 222 p.

5. E. N. LUKASHOVA South America. - M .: 1958.

6. Pritula T.Yu., Eremina V.A., Spryalin A.N. Physical geography of continents and oceans. - M .: Vlados, 2003 .-- 680 p.

7. Physical geography of continents and oceans / Ed. Ryabchikova A.M. M .: Higher school, 1988 .-- 588 p.

8. Finarov D.P. Geography: Continents, oceans and countries / D.P. Finarov, S.V. Vasiliev, E. Ya. Chernikhova - M .: Astrel, AST; SP: SpetsLit, 2001 .-- 300 p.

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§one. Classification of anthropogenic impacts

Anthropogenic impacts include all impacts that depress the nature, created by technology or directly by humans. They can be combined into the following groups:

1) pollution, i.e. introducing into the environment uncharacteristic for it physical, chemical and other elements or artificially increasing the existing natural level of these elements;

2) technical transformations and destruction of natural systems and landscapes in the process of extraction of natural resources, construction, etc .;

3) withdrawal of natural resources - water, air, minerals, organic fuel, etc .;

4) global climatic impacts;

5) violation of the aesthetic value of landscapes, i.e. change in natural forms, unfavorable for visual perception.

Some of the most significant negative impacts on nature are pollution, which are classified according to type, source, consequences, control measures, etc. Sources of anthropogenic pollution are industrial and agricultural enterprises, energy facilities, transport. Household pollution makes a significant contribution to the overall balance.

Anthropogenic pollution can be local, regional and global. They are divided into the following types:

Biological,

Mechanical,

Chemical,

Physical,

· Physical and chemical.

Biological, as well as microbiological pollution occurs when biological waste enters the environment or as a result of the rapid multiplication of microorganisms on anthropogenic substrates.

Mechanical pollution is associated with substances that do not have physical and chemical effects on organisms and the environment. It is typical for the processes of production of building materials, construction, repair and reconstruction of buildings and structures: it is waste of stone sawing, production of reinforced concrete, bricks, etc. The cement industry, for example, ranks first in terms of emissions of solid pollutants (dust) into the atmosphere, followed by factories for the production of sand-lime bricks, lime plants and porous aggregate factories.

Chemical pollution can be caused by the introduction of any new chemical compounds into the environment or an increase in the concentration of already present substances. Many of the chemicals are active and can interact with the molecules of substances inside living organisms or actively oxidize in air, thus becoming toxic to them. The following groups of chemical contaminants are distinguished:

1) aqueous solutions and slimes with acidic, alkaline and neutral reactions;

2) non-aqueous solutions and sludge (organic solvents, resins, oils, fats);

3) solid pollution (chemically active dust);

4) gaseous pollution (vapors, waste gases);

5) specific - especially toxic (asbestos, compounds of mercury, arsenic, lead, phenol-containing pollution).

Based on the results of international research carried out under the auspices of the United Nations, a list of the most important substances that pollute the environment has been compiled. It included:

§ sulfur trioxide (sulfuric anhydride) SO 3;

Suspended particles;

§ carbon oxides CO and CO 2

§ nitrogen oxides NO x;

§ photochemical oxidants (ozone О 3, hydrogen peroxide Н 2 О 2, hydroxyl radicals ОН -, PAN peroxyacyl nitrates and aldehydes);

§ mercury Hg;

§ lead Pb;

§ cadmium Cd;

§ chlorinated organic compounds;

§ toxins of fungal origin;

§ nitrates, more often in the form of NaNO 3;

§ ammonia NH 3;

§ certain microbial contaminants;

§ radioactive contamination.

According to their ability to survive under external influence, chemical contamination is divided into:

a) persistent and

b) destroyed by chemical or biological processes.

TO physical include pollution:

1) thermal, arising as a result of an increase in temperature due to heat losses in industry, residential buildings, in heating mains, etc.;

2) noise as a result of increased noise of enterprises, transport, etc .;

3) light, arising as a result of unreasonably high illumination created by artificial light sources;

4) electromagnetic from radio, television, industrial installations, power lines;

5) radioactive.

Pollution from various sources enters the atmosphere, water bodies, lithosphere, after which it begins to migrate in different directions. From the habitats of a separate biotic community, they are transferred to all components of the biocenosis - plants, microorganisms, animals. Directions and forms of pollution migration can be as follows (Table 2):

table 2

Forms of migration of pollution between natural environments

Migration direction

Migration forms

Atmosphere - atmosphere Atmosphere - hydrosphere Atmosphere - land surface Atmosphere - biota Hydrosphere - atmosphere Hydrosphere - hydrosphere Hydrosphere - land surface, bottom of rivers, lakes Hydrosphere - biota Land surface - hydrosphere Land surface - land surface Land surface - atmosphere Land surface - biota Biota - atmosphere Biota - hydrosphere Biota - land surface Biota - biota

Transport in the atmosphere Sedimentation (leaching) on ​​the water surface Sedimentation (leaching) on ​​the land surface Sedimentation on the plant surface (foliar intake) Evaporation from water (oil products, mercury compounds) Transport in water systems Transfer from water to soil, filtration, self-purification of water, sedimentation pollution Transition from surface waters to terrestrial and aquatic ecosystems, entering organisms with drinking water Flushing with precipitation, temporary watercourses, during snow melting Migration in soil, glaciers, snow cover Blowing away and transport by air masses Root input of pollution into vegetation Evaporation Intake of water after death organisms Entry into the soil after the death of organisms Migration along food chains

Construction production is a powerful tool destruction of natural systems and landscapes... The construction of industrial and civil facilities leads to the rejection of large areas of fertile land, a reduction in the living space of all ecosystem inhabitants, and a serious change in the geological environment. Table 3 illustrates the results of the impact of construction on the geological structure of the territories.

Table 3

Changes in the geological environment at construction sites

Environmental disturbances are accompanied by the extraction and processing of minerals. This is expressed in the following.

1. Creation of large-scale open pits and embankments leads to the formation of a technogenic landscape, a reduction in land resources, deformation of the earth's surface, impoverishment and destruction of soils.

2. Drainage of deposits, water intake for technical needs of mining enterprises, discharge of mine and waste waters violate the hydrological regime of the water basin, deplete the reserves of underground and surface waters, and worsen their quality.

3. Drilling, blasting, loading of rock mass is accompanied by a deterioration in the quality of atmospheric air.

4. The above processes, as well as industrial noise, contribute to the deterioration of living conditions and a decrease in the number and species composition of plants and animals, and a decrease in crop yields.

5. Mining, drainage of deposits, extraction of minerals, burial of solid and liquid waste lead to a change in the natural stress-strain state of the rock mass, flooding and watering of deposits, pollution of the subsoil.

Nowadays, disturbed territories appear and develop practically in every city. territories with a threshold (supercritical) change in any characteristic of geotechnical conditions. Any such change limits the specific functional use of the area and requires reclamation, i.e. a set of works aimed at restoring the biological and economic value of disturbed lands.

One of the main reasons depletion of natural resources is the extravagance of people. So, according to some experts, the explored reserves of minerals will be completely depleted in 60-70 years. Known oil and gas deposits can be depleted even faster.

At the same time, only 1/3 of the consumed raw materials are directly spent on the production of industrial products, and 2/3 is lost in the form of by-products and waste that pollute the natural environment (Fig. 9).

Throughout the history of human society, about 20 billion tons of ferrous metals have been smelted, and in structures, cars, transport, etc. only 6 billion tons of them were sold. The rest is scattered in the environment. Currently, more than 25% of the annual production of iron is dispersed, and even more of some other substances. For example, the dispersion of mercury and lead amounts to 80 - 90% of their annual production.

NATURAL DEPOSITS

Retrieved Left

Losses

Recycling Partial refund

Partial return

Products

Failure, wear, corrosion

Scrap Environmental pollution

Fig. 9. Resource cycle diagram

The balance of oxygen on the planet is on the verge of disruption: at the current rate of deforestation, photosynthetic plants will soon be unable to reimburse it for the needs of industry, transport, energy, etc.

Global climate change caused by human activities are characterized primarily by a global rise in temperature. Experts believe that in the next decade, the warming up of the earth's atmosphere may increase to a dangerous level: in the tropics, temperatures are predicted to rise by 1-2 0 C, and near the poles by 6-8 0 C.

Due to the melting of polar ice, the level of the World Ocean will rise noticeably, which will lead to the flooding of huge populated areas and agricultural areas. The associated massive epidemics are predicted, especially in South America, India, the Mediterranean countries. The number of oncological diseases will increase everywhere. The power of tropical cyclones, hurricanes, tornadoes will significantly increase.

The root cause of it all is the greenhouse effect caused by an increase in the concentration in the stratosphere at an altitude of 15-50 km of gases that are usually not present there: carbon dioxide, methane, nitrogen oxides, chlorofluorocarbons. A layer of these gases acts as an optical filter, letting in the sun's rays and retaining thermal radiation reflected from the earth's surface. This causes the temperature to rise in the surface area, as under the roof of a greenhouse. And the intensity of this process is growing: in the last 30 years alone, the concentration of carbon dioxide in the air has increased by 8%, and in the period from 2030 to 2070, its content in the atmosphere is expected to double compared to the pre-industrial level.

Thus, the global temperature rise in the coming decades and the associated adverse events are beyond doubt. At the present level of development of civilization, it is only possible to slow down this process in one way or another. Thus, the all-round saving of fuel and energy resources directly contributes to a slowdown in the rate of atmospheric heating. Further steps in this direction are the transition to resource-saving technologies and devices, to new construction projects.

By some estimates, significant warming has already been delayed by 20 years, thanks to the almost complete cessation of the production and use of chlorofluorocarbons in industrialized countries.

At the same time, there are a number of natural factors that restrain climate warming on Earth, for example, stratospheric aerosol layer, formed by volcanic eruptions. It is located at an altitude of 20-25 km and consists mainly of sulfuric acid droplets with an average size of 0.3 microns. It also contains particles of salts, metals, and other substances.

Particles from the aerosol layer reflect solar radiation back into space, which leads to a slight decrease in temperature in the surface layer. Despite the fact that there are about 100 times less particles in the stratosphere than in the lower atmosphere - the troposphere - they have a more noticeable climatic effect. This is due to the fact that the stratospheric aerosol mainly lowers the air temperature, while the tropospheric aerosol can both lower and increase it. In addition, each particle in the stratosphere exists for a long time - up to 2 years, while the lifetime of tropospheric particles does not exceed 10 days: they are quickly washed out by rains and fall to the ground.

Violation of the aesthetic value of landscapes typical for construction processes: the construction of non-scale natural formations of buildings and structures makes a negative impression, worsens the historically formed appearance of landscapes.

All technogenic impacts lead to a deterioration in the quality indicators of the environment, which are distinguished by conservatism, since they were developed over millions of years of evolution.

To assess the activity of anthropogenic impact on the nature of the Kirov region, an integral anthropogenic load was established for each district, obtained on the basis of assessments of the environmental impact of three types of pollution sources:

§ local (household and industrial waste);

§ territorial (agriculture and forest exploitation);

§ local-territorial (transport).

It has been established that the areas with the highest environmental stress include: Kirov, district and Kirovo-Chepetsk, district and Vyatskiye Polyany, district and Kotelnich, district and Slobodskoy.

7th grade.

Lesson objectives

Educational:

to consolidate and deepen knowledge about the basic law of geography - latitudinal zoning using the example of the natural zones of South America;

explore the features of the natural areas of South America.

Show the relationship between the components of the nature of the continent, the influence of relief, climate and inland waters on the development of the organic world of South America;

Developing:

continue to improve the ability to analyze thematic maps;

to work out the ability of students to characterize natural zones, to identify the relationship between natural components;

develop skills for choosing the rational performance of stages of work.

Educational:

assess the degree of change in nature under the influence of human economic activity;

foster mutual understanding, mutual assistance, friendship in the process of working together for a result.

To educate schoolchildren to respect nature

A type lesson: learning new material. Equipment:

textbook of geography "Continents, oceans and countries" I. V. Korinskaya, V.А. Dushina, atlases on geography, grade 7,

notebooks, tables for filling,

multimedia projector,

drawings of students,

wall map of South America.

Methods and Forms : partial search, explanatory and illustrative, visual, reproductive, independent work, individual.

Stroke lesson.

I. Organizational moment.

Today in the lesson we will continue to study the nature of South America: we will find out what natural zones are on this continent, we will give them a description. Let's get acquainted with new concepts, listen to messages prepared by the guys. Let us consider how the nature of the continent changes under the influence of man's c / d, what negative effect man has on the flora and fauna. Let's formulate the rules of respect for nature. Write the number and topic of the lesson in a notebook.

Learning new material.

(guys open the atlases on page FZ. let's see what natural zones have formed on the mainland).

Due to the prevalence of a humid climate in South America, forests are widespread and relatively little desert and semi-desert. On both sides of the equator in the Amazon, constantly moist evergreen forests stretch, alternating to the north and south in the highlands with variable moist deciduous tropical forests, woodlands and savannas, especially extensive in the southern hemisphere. In the south of the mainland, there are steppes and semi-deserts. A narrow strip within the tropical climatic zone in the west is occupied by the Atacama Desert, (recorded natural zones in a notebook)

Like Australia, South America stands out among the continents for the originality of the organic world. Long-term isolation from other continents contributed to the formation of a rich and largely endemic flora and fauna in South America. It is the birthplace of the rubber plant of the hevea, the chocolate tree, the cinchona and red trees, Victoria Region, as well as many cultivated plants - potatoes, tomatoes, beans. Among the endemics of the animal world, one should name the edentulous (anteaters, armadillos, sloths) broad-nosed monkeys, llamas, some rodents (capybara, chinchilla).

Now we will listen to messages about the peculiarities of the flora and fauna, those landmarks that occupy the largest areas on the mainland. Be careful, I am giving you tables with partial characteristics of P.Z., however, not all columns contain information. The task is to fill them in as you go along the message.

Natural area

Climate

Soil

Vegetation b

Animal world

Human influence

Wet equatorial forests - selva

On either side of the equator, on

Amazonian th

lowlands

Equatorial

belt:

hot and humid

Red-yellow ferralite

Howler monkey, sloth, anteater, tapir, jaguar, parrots, hummingbirds

Savannah

Orinokskaya

lowland,

Guiana, Brazilian

plateaus.

Subequatrial: hot, tropical zone:

dry and hot

Red ferralite

Acacia,

palms, cactus,

mimosa,

spurge,

kebracho,

shrubs,

bottle

tree.

In place

rainforest

are created

plantations

coffee

trees

Steppe - pampa

South of the savannahs to 40 ° S latitude.

Subtropical

belt:

warm and humid

Reddish

black

Feather grass,

millet,

reeds

Pampas deer, llama, nutria, armadillo,

pampas cat

Semi-desert - Patagonia

Of America

Subtropical, temperate zone: dry and cool "

Brown,

gray-

brown

Cereals,

cushion

shrubs

Viskasha, nutria, armadillos

Natural area

Climate

Soil

Vegetation

Animal world

Human influence

Wet equatorial forests - selwa

Equatorial

belt:

hot and humid

Red-yellow ferralite

Chocolate tree, cinchona tree, palms, ceiba, spurge, melon tree, hevea, liana, orchid

Deforestation that provides a lot of oxygen

Savannah

Orinokskaya

degrade

Guiana, Brazilian

plateaus.

Red ferralite

Deer, bakers, anteaters, armadillos, jaguars, cougars, ostrich rhea

In place

rainforest

are created

plantations

coffee

trees

Steppe - pampa

South of the savannahs to 40 ° S latitude.

Reddish

black

Feather grass,

millet,

reeds

Wheat, corn fields, grazing pens, cutting down conifers

Semi-desert - Patagonia

A narrow strip along the Andes in the south of the South.

Of America

Subtropical, temperate: dry and cool

Brown,

gray-

brown

Viskasha, nutria, armadillos

The guys read out the messages, after each we check what we have added in the table.

Wet equatorial forests.

Steppe - pampa.

Semi-desert.

So, we have listened with you messages about the main P.Z., proved that the flora and fauna of South America is endemic and diverse. And now we will assess the degree of change in the nature of the continent under the influence of c / d man.

A nature poem and message are read.

Somehow, having gathered with the last forces,

The Lord created a beautiful planet.

He gave her the shape of a big ball,

And planted there trees, flowers,

Herbs of unprecedented beauty.

Many animals began to be found there:

Snakes, elephants, turtles and birds.

Here's a gift for you, people, own it.

Plow the land, sow bread.

I will bequeath to you from now on -

You take care of this shrine!

Everything was fine, of course,

But .... civilization has come to Earth.

Technological progress broke free.

The scientific world, dormant until now, suddenly resurrected,

And gave the earthly population

Their infernal inventions.

Conclusion: we are showing a slide on the negative impact of humans. We trace the scheme into a notebook.

Your homework assignment was to formulate the rules of respect for nature. Please, who cooked, let's hear. Conservation slide.

To preserve the flora and fauna, it is necessary to take good care of nature, create specially protected areas - reserves, - national parks, create various centers and organizations for the protection of the environment. After all, our health depends on how we relate to nature. We trace the scheme into a notebook.

III. Comprehension.

What explains the species diversity of flora and fauna in South America?

List the main natural areas of South America, (according to the table)

IV. Summarizing.

To all the guys who prepared the messages with a score of "5"

Rate those who responded during the lesson.

V. Homework

§ 44 attach the table to a notebook, learn.

In South America, there are many environmental problems caused by technological progress and economic development. Forests are being destroyed and water bodies polluted, biodiversity is diminishing and soil is depleted, the atmosphere is being polluted and wildlife habitats are diminishing. All this can lead to an environmental disaster in the future.
In the cities of South American countries, environmental problems of the following nature have formed:

• the problem of unsanitary conditions;
• water pollution;
• the problem of garbage and solid waste disposal;
• air pollution;
• the problem of energy resources, etc.

Deforestation problem

Much of the mainland is covered by tropical forests, which are the lungs of the planet. Trees are constantly cut down not only to sell timber, but also to create agricultural land and pastures. All this leads to a change in the forest ecosystem, the destruction of some species of flora and the migration of fauna. In order to preserve the forest, many countries regulate logging activities at the legislative level. There are whole zones where it is prohibited, reforestation and new trees are being planted.

Hydrosphere problems

In the coastal areas of the seas and oceans, there are many problems:

• overfishing;
• pollution of water with garbage, oil products and chemicals;
• housing and communal and industrial effluents.

All these wastes negatively affect the state of water bodies, flora and fauna.

In addition, many rivers flow along the mainland, including the largest river in the world - the Amazon. The rivers of South America are also affected by human activity. Many species of fish and animals disappear in the waters. The life of local tribes, who have lived on the banks of rivers for thousands of years, has also become very complicated, they are forced to look for new habitats for themselves. Dams and various structures have led to changes in river regimes and water pollution.

Biosphere pollution

The source of air pollution is the greenhouse gases emitted by vehicles and industrial plants:

• mines and deposits;
• chemical industry enterprises;
• oil refineries;
• energy facilities;
• metallurgical plants.

Agriculture, which uses pesticides, chemical and mineral fertilizers, contributes to soil pollution. Soil is also depleted, leading to soil degradation. Land resources are being destroyed.

HUMAN SETTLEMENT AND INFLUENCE ON THE NATURE OF SOUTH AMERICA

South America is mastered by man unevenly... Only the marginal areas of the mainland are densely populated, mainly the coast of the Atlantic Ocean and some areas of the Andes. At the same time, the interior regions, for example, the wooded Amazonian lowland, have remained virtually undeveloped until recently.

The question of the origin of the indigenous population of South America - the Indians - has long been controversial.

The most common point of view about the settlement of South America by Mongoloids from Asia across North America about 17-19 thousand years ago (Fig. 23).

Rice. 23. Centers for the formation of man and the ways of his settlement around the globe(according to V.P. Alekseev): 1 - the ancestral home of mankind and resettlement from it; 2 - primary western focus of race formation and dispersal of proto-Australoids; 3 - resettlement of protoevropoids; 4 - resettlement of protonegroids; 5 - primary eastern focus of race formation and dispersal of protoamericanoids; 6 - North American Tertiary focus and dispersal from it; 7 - Central South American focus and dispersal from it.

But, based on some anthropological commonality of the Indian peoples of South America with the peoples of Oceania (wide nose, wavy hair) and on the presence of the same tools of labor, some scientists expressed the idea of ​​settling South America from the Pacific Islands... However, this point of view is shared by few. Most scientists are inclined to explain the presence of Oceanian features among the inhabitants of South America by the fact that representatives of the Oceanic race could have penetrated through the northeast of Asia and North America with the Mongoloids.

Currently number of Indians in South America it is much higher than in North America, although during the period of colonization of the mainland by Europeans, it has greatly decreased. In some countries, Indians still make up a significant percentage of the population. In Peru, Ecuador and Bolivia, they are about half of the total number, and in some areas they even significantly predominate. Most of the population of Paraguay is of Indian origin, many Indians live in Colombia. In Argentina, Uruguay, Chile, the Indians were almost completely exterminated in the first period of colonization, and now there are very few of them. Brazil's Indian population is also steadily declining.

Anthropologically, all the Indians of South America are distinguished by their unity and are close to the North American Indians. The most developed classification of Indian peoples by language... The diversity of the languages ​​of the Indians of South America is very great and many of them are so peculiar that they cannot be united into families or groups. In addition, individual linguistic families and individual languages, previously widespread across the mainland, have now almost or completely disappeared along with the peoples who spoke them, as a result of European colonization. The languages ​​of many Indian tribes and peoples living in isolation are still almost unexplored. By the beginning of European colonization, the territory east of the Andes was inhabited by peoples whose level of development corresponded to the primitive communal system. They obtained their livelihood by hunting, fishing and gathering. But, according to recent studies, in some plains of the north and northeast of the mainland, a large population was engaged in agriculture on drained lands.

In the Andes and on the Pacific coast strong Indian states, characterized by a high level of development of agriculture and animal husbandry, crafts, applied arts and the rudiments of scientific knowledge.

The agricultural peoples of South America gave the world such cultivated plants as potatoes, cassava, peanuts, pumpkin, etc. (see the map "Centers of origin of cultivated plants" in Fig. 19).

In the process of European colonization and a fierce struggle against the colonialists, some Indian peoples completely disappeared from the face of the Earth, others were pushed back from their ancestral territories to uninhabited and inconvenient lands. Individual Indian peoples continue to live in areas of their former habitat. Until now, there are tribes living in isolation, retaining the level of development and way of life at which they were found by the invasion of Europeans.

Listed below are only a few, the most numerous and most well-studied groups of Indian peoples who now or have made up in the past a significant part of the mainland's population.

Remnants still exist in the interior of Brazil. tribes of the language family "same"... By the time the Europeans arrived on the mainland, they inhabited the eastern and southern parts of Brazil, but were pushed aside by the colonialists into forests and swamps. This people is still at a level of development corresponding to the primitive communal system, and is distinguished by a wandering way of life.

They were at a very low stage of development before the arrival of Europeans residents of the extreme south of South America(Tierra del Fuego). They protected themselves from the cold with animal skins, weapons were made of bone and stone, food was obtained by hunting guanacos and sea fishing. Fire-earthers were subjected to the most severe physical extermination in the 19th century, now there are very few of them.

At a higher level of development were the tribes inhabiting the central and northern parts of the continent in the Orinoco and Amazon basins ( peoples of the language families Tupi-Guarani, Arawak, Caribbean). They are still engaged in agriculture, cultivating cassava, corn, cotton. They hunt using bows and arrow-throwing tubes, and also use the instantly acting plant poison curare.

Before the arrival of Europeans, the main occupation of the tribes living in the territory Argentine Pampa and Patagonia, there was a hunt. The Spaniards brought horses to the mainland, which subsequently ran wild. The Indians learned to tame horses and began to use them to hunt guanacos. The rapid development of capitalism in Europe was accompanied by the ruthless extermination of the population of the colonial lands. In Argentina, in particular, the local residents were pushed back by the Spaniards to the extreme south of Patagonia, to lands unsuitable for grain farming. Currently, in Pampa, the indigenous population is almost completely absent. Only small groups of Indians have survived, working as laborers on large agricultural farms.

The highest socio-economic and cultural development by the arrival of Europeans was reached by the tribes inhabiting the elevated highlands of the Andes within Peru, Bolivia and Ecuador, where one of the oldest centers of irrigated agriculture is located.

Indian tribe Quechua language family, who lived in the XI-XIII centuries. on the territory of modern Peru, united the scattered small peoples of the Andes and formed a strong state, Tahuantinsuyu (XV century). The leaders were called "Inca". Hence the name of the whole people came from. The Incas subjugated the peoples of the Andes up to the modern territory of Chile, spread their influence also to the more southern regions, where an independent, but close to the Inca culture of sedentary farmers arose araucanov (mapuche).

Irrigated agriculture was the main occupation of the Incas, and they cultivated up to 40 species of cultivated plants, placing fields in terraces along the slopes of the mountains and bringing the water of mountain streams to them. The Incas tamed wild llamas, using them as beasts of burden, and bred domestic llamas, from which they received milk, meat, wool. The Incas were also famous for their ability to build mountain roads and bridges from vines. They knew many crafts: pottery, weaving, processing of gold and copper, etc. From gold they made jewelry and religious objects. In the Inca state, private land ownership was combined with collective land ownership; the state was headed by a supreme leader with unlimited power. From the conquered tribes, the Incas collected taxes. The Incas are the creators of one of the oldest civilizations in South America. Some monuments of their culture have survived to this day: ancient tracts, the remains of architectural structures and irrigation systems.

Individual peoples that were part of the Inca state still inhabit the desert high plateaus of the Andes. They cultivate the land in a primitive way, cultivating potatoes, quinoa and some other plants.

The most numerous modern Indian people - Quechua- inhabits the mountainous regions of Peru, Bolivia, Ecuador, Chile and Argentina. On the shores of Lake Titicaca live Aymara- one of the most mountainous peoples in the world.

The core of the indigenous population of Chile was formed by a group of strong agricultural tribes, united under a common name araucans... They put up a long resistance to the Spaniards, and only in the 18th century. some of them, under the onslaught of the colonialists, moved to Pampa. Now the Araucans (Mapuche) live in the southern half of Chile, only a few of them - in the Argentine Pampa.

In the north of the Andes, on the territory of modern Colombia, a cultural state of peoples was formed by the arrival of the Spanish conquerors chibcha-muiska... Now small tribes - the descendants of the Chibcha, who have preserved remnants of the tribal system, live in Colombia and the Isthmus of Panama.

The first settlers from Europe to come to America without families married Indian women. As a result, mixed, mixed, population. The crossbreeding process continued later.

Currently, "pure" representatives of the Caucasian race are almost completely absent on the mainland. The only exceptions are later immigrants. Most of the so-called "whites" contain, to one degree or another, an admixture of Indian (or Negro) blood. This mixed population (mestizo, cholo) predominates in almost all South American countries.

A significant part of the population, especially in the Atlantic regions (in Brazil, Guiana, Suriname, Guyana), is black people- the descendants of slaves brought into South America at the beginning of colonization, when a large and cheap labor force was needed for plantations. Blacks partially mingled with white and Indian populations. As a result, mixed types were created: in the first case - mulattoes, in the second - sambo.

Fleeing from exploitation, negro slaves fled from their masters to the rainforests. Their descendants, some of whom mixed with the Indians, still lead a primitive forest lifestyle in some areas.

Before the declaration of independence of the South American republics, i.e. until the first half of the 19th century, immigration to South America from other countries was prohibited. But subsequently, the governments of the newly formed republics, interested in the economic development of their states, the development of vacant lands, opened access immigrants from different countries of Europe and Asia. Especially many citizens arrived from Italy, Germany, the Balkan countries, partly from Russia, China and Japan. The settlers of the later period usually keep apart, retaining their language, customs, culture and religion. In some republics (Brazil, Argentina, Uruguay), they form significant groups of the population.

The peculiarities of the history of South America and, as a consequence, the great unevenness in the distribution of the modern population and its relatively low average density have led to a significant preservation of natural conditions in comparison with other continents. Large areas of the Amazonian lowland, the central part of the Guiana Highlands (Roraima massif), the southwestern part of the Andes and the Pacific coast remained for a long time undeveloped... Separate roving tribes in the Amazonian forests, almost not in contact with the rest of the population, not so much influenced nature as they themselves depended on it. However, such areas are becoming less and less. Extraction of minerals, laying of communication lines, in particular construction Trans-Amazonian Highway, the development of new lands in South America is leaving less and less space untouched by human activity.

Extraction of oil in the very thick of the Amazon rainforest or of iron and other ores within the Guiana and Brazilian highlands required the construction of transport routes in the recently still remote and inaccessible areas. This, in turn, led to an increase in population, destruction of forests, expansion of arable and pasture lands. As a result of an attack on nature using the latest technology, the ecological balance is often disturbed, and vulnerable natural complexes are destroyed (Fig. 87).

Rice. 87. Environmental problems of South America

The development and significant transformations began primarily from the La Plata plain, the coastal parts of the Brazilian Highlands, the extreme north of the mainland. The areas that were developed even before the beginning of European colonization are located in the depths of the Andes of Bolivia, Peru and other countries. On the territory of the most ancient Indian civilizations, centuries of human activity have left their mark on the desert plateaus and mountain slopes at an altitude of 3-4.5 thousand meters above sea level.