The study of the geography of Russia by natural zones. Thermal belts of the Earth

The climate of Russia has a special differentiation, incomparable with any other country in the world. This is due to the wide extent of the country across Eurasia, the heterogeneity of the location of reservoirs and the great variety of relief: from high mountain peaks to plains lying below sea level.

Russia is predominantly located in middle and high latitudes. Whereby weather most of the country is harsh, the seasons change clearly, and winters are long and frosty. The Atlantic Ocean has a significant influence on the climate of Russia. Despite the fact that its waters do not touch the territory of the country, it controls the transport air masses in temperate latitudes, where it is located most of countries. Since there are no high mountains in the western part, the air masses pass unhindered up to the Verkhoyansk Range. In winter, they help to mitigate frosts, and in summer they provoke cooling and precipitation.

Climatic zones and regions of Russia

(Map-scheme of climatic zones of Russia)

On the territory of Russia there are 4 climatic zones:

arctic climate

(Islands of the Arctic Ocean, coastal regions of Siberia)

Arctic air masses prevailing year-round, combined with extremely low solar exposure, are the cause of severe weather conditions. In winter, during the polar night, the average daily temperature does not exceed -30°C. In summer, most of the sun's rays are reflected off the surface of the snow. Therefore, the atmosphere does not warm up above 0 ° C ...

subarctic climate

(Region along the Arctic Circle)

In winter, weather conditions are close to arctic, but summers are warmer (in the southern parts, the air temperature can rise up to +10°C). Precipitation exceeds evaporation...

Temperate climate

• Continental(West Siberian Plain in the south and in the central part). The climate is characterized by low rainfall and a wide range of temperatures during winter and summer time.
• temperate continental(European part). The western transport of air masses brings air from the Atlantic Ocean. In this regard, winter temperatures rarely drop to -25 ° C, thaws occur. Summer is warm: in the south up to +25°С, in the northern part up to +18°С. Precipitation falls unevenly from 800 mm per year in the northwest to 250 mm in the south.
• sharply continental(Eastern Siberia). The inland position and the absence of the influence of the oceans explain the strong heating of the air during the short summer (up to +20°C) and the sharp cooling in winter (reaches -48°C). The annual rainfall does not exceed 520 mm.
• Monsoon continental(southern part Far East ). With the onset of winter, dry and cold continental air arrives, due to which the air temperature drops to -30 ° C, but there is little precipitation. In summer, under the influence of air masses from the Pacific Ocean, the temperature cannot rise above +20°C.

subtropical climate

(Black Sea coast, Caucasus)

narrow lane subtropical climate protected by the mountains of the Caucasus from the passage of cold air masses. This is the only part of the country where winter months the air temperature is positive, and the duration of summer is much longer than in the rest of the region. Nautical wet air produces up to 1000 mm of precipitation per year ...

Climatic zones of Russia

(Map climatic zones Russia)

Zoning takes place on 4 conditional areas:

• First- tropical ( Southern parts of Russia);
• Second- subtropical ( Primorye, western and northwestern regions);
• Third- moderate ( Siberia, Far East);
• 4th- polar ( Yakutia, more northern regions Siberia, the Urals and the Far East).

In addition to the four main zones, there is the so-called "special" zone, which includes areas beyond the Arctic Circle, as well as Chukotka. The division into areas with approximately similar climate occurs due to uneven heating of the earth's surface by the Sun. In Russia, this division coincides with meridians that are multiples of 20: 20th, 40th, 60th and 80th.

The climate of the regions of Russia

Each region of the country is characterized by special climatic conditions. In the northern regions of Siberia, Yakutia, negative average annual temperatures and short summer.

A distinctive feature of the Far Eastern climate is its contrast. Traveling towards the ocean, one notices a change from continental to monsoonal climate.

AT Central Russia the division into seasons is distinct: hot summer gives way to a short autumn, and after a cool winter, spring comes with increased level precipitation.

The climate of the South of Russia is ideal for recreation: the sea does not have time to cool much in time warm winter and the tourist season starts at the end of April.

Climate and seasons of the regions of Russia:

The diversity of the climate of Russia is due to the vastness of the territory and openness to the Arctic Ocean. The large length explains the significant difference in average annual temperatures, the uneven effects of solar radiation and heating of the country. For the most part, severe weather conditions are noted with a pronounced continental character and a clear change in temperature regimes and precipitation according to the seasons.

Zoning - change natural ingredients and the natural complex as a whole from the equator to the poles. The basis of zoning is the different supply of heat, light, precipitation, which, in turn, are already reflected in all other components, and above all, soils, flora and fauna.

Zoning is characteristic of both land and the oceans.

The largest zonal divisions of the geographical shell - geographic zones. Belts differ from each other primarily in temperature conditions.

The following geographical zones are distinguished: equatorial, subequatorial, tropical, subtropical, temperate, subpolar, polar (antarctic and arctic).

Inside the belts on land allocate natural areas, each of which is characterized not only by the same type of temperature conditions and moisture, which leads to a commonality of vegetation, soils and wildlife.

You are already familiar with the arctic desert zone, tundra, temperate forest zone, steppes, deserts, wet and dry subtropics, savannahs, humid equatorial evergreen forests.

Within natural zones, transitional areas are distinguished. They are formed as a result of gradual changes in climatic conditions. Such transitional zones include, for example, forest-tundra, forest-steppes and semi-deserts.

Zoning is not only latitudinal, but also vertical. Vertical zoning is a regular change natural complexes in height and depth. For mountains, the main cause of this zonality is the change in temperature and amount of moisture with height, and for the depths of the ocean, heat and sunlight.

The change of natural zones depending on the height above sea level in mountainous areas is called, as you already know, altitudinal zonation.

It differs from horizontal zonality in the length of belts and the presence of a belt of alpine and subalpine meadows. The number of belts usually increases in high mountains and as we approach the equator.

natural areas

natural areas- large subdivisions of the geographical envelope, which have a certain combination of temperature conditions and moisture regime. They are classified mainly according to the prevailing type of vegetation and regularly change in the plains from north to south, and in the mountains - from the foot to the peaks. The natural zones of Russia are shown in fig. one.

The latitudinal distribution of natural zones on the plains is explained by the supply of unequal amounts of solar heat and moisture to the earth's surface at different latitudes.

Resources of flora and fauna of natural zones are biological resources territory.

The set of altitudinal belts depends primarily on the latitude at which the mountains are located and what their height is. It should also be noted that for the most part the boundaries between the altitudinal zones are not clear.

Let us consider in more detail the features of the placement of natural zones on the example of the territory of our country.

polar desert

The very north of our country - the islands of the Arctic Ocean - are located in the natural zone polar (arctic) deserts. This area is also called ice zone. The southern boundary roughly coincides with the 75th parallel. The natural zone is characterized by the dominance of arctic air masses. The total solar radiation is 57-67 kcal/cm2 per year. Snow cover lasts 280-300 days a year.

In winter, the polar night dominates here, which at a latitude of 75 ° N. sh. lasts 98 days.

In summer, even round-the-clock lighting is not able to provide enough heat to this area. The air temperature rarely rises above 0 °C, and the average July temperature is +5 °C. For several days there may be drizzling precipitation, but there are practically no thunderstorms and showers. But there are frequent fogs.

Rice. 1. Natural areas of Russia

A significant part of the territory is characterized by modern glaciation. There is no continuous vegetation cover. The near-glacial areas of land on which vegetation develops are small areas. On placers of pebbles, fragments of basalt and boulders, mosses and scale lichens “settle”. Occasionally there are poppies and saxifrages that begin to bloom when the snow barely has time to melt.

The fauna of the Arctic desert is represented mainly by marine life. These are the harp seal, walrus, ringed seal, sea hare, white whale, porpoise, killer whale.

Species of baleen whales are diverse in the northern seas. Blue and bowhead whales, sei whale, fin whale, humpback whale are rare and endangered species and are listed in the Red Book. The inner side of the long horny plates that replace the teeth of whales is split into hairs. This allows the animals to filter large volumes of water, harvesting the plankton that forms the basis of their diet.

The polar bear is also a typical representative of the animal world of the polar desert. The "maternity hospitals" of polar bears are located on Franz Josef Land, Novaya Zemlya, about. Wrangel.

In summer, numerous colonies of birds nest on the rocky islands: gulls, guillemots, guillemots, auks, etc.

There is practically no permanent population in the polar desert zone. The meteorological stations operating here monitor the weather and the movement of ice in the ocean. On the islands, foxes are hunted in winter and game birds in summer. Fishing is carried out in the waters of the Arctic Ocean.

Steppes

Steppes extend south of the forest-steppe zone. They are distinguished by the absence of forest vegetation. The steppes stretch in a narrow continuous strip in the south of Russia from the western borders to Altai. Further to the east, the steppe areas have a patchy distribution.

The climate of the steppes is temperate continental, but drier than in the zone of forests and forest-steppes. The amount of annual total solar radiation reaches 120 kcal/cm 2 . The average January temperature in the west is -2 °С, and in the east -20 °С and lower. Summer in the steppe is sunny and hot. The average temperature in July is 22-23 °С. The sum of active temperatures is 3500 °C. Precipitation falls 250-400 mm per year. Showers are frequent in summer. The moisture coefficient is less than unity (from 0.6 in the north of the zone to 0.3 in the southern steppes). Steady snow cover lasts up to 150 days a year. In the west of the zone, thaws often occur, so the snow cover there is thin and very unstable. The predominant soils of the steppes are chernozems.

Natural plant communities are represented mainly by perennial, drought- and frost-resistant herbs with a strong root system. First of all, these are cereals: feather grass, fescue, wheatgrass, snake, thin-legged, bluegrass. In addition to cereals, there are numerous representatives of herbs: astragalus, sage, cloves - and bulbous perennials, such as tulips.

Composition and structure plant communities vary significantly both in the latitudinal and in the meridional direction.

In the European steppes, narrow-leaved grasses form the basis: feather grass, fescue, bluegrass, fescue, thin-legged, etc. There are many brightly flowering herbs. In summer, like waves in the sea, feather grass sways, here and there you can see lilac irises. In the drier southern regions, in addition to cereals, wormwood, thorax, and cinquefoil are common. Lots of tulips in spring. In the Asian part of the country, tansy and cereals predominate.

Steppe landscapes are fundamentally different from forest ones, which determines the uniqueness of the animal world of this natural zone. Typical animals of this zone are rodents (the most numerous group) and ungulates.

Ungulates are adapted to long-term movements across the vast expanses of the steppes. Due to the thinness of the snow cover, plant food is also available in winter. An important role in nutrition is played by bulbs, tubers, rhizomes. For many animals, plants are also the main source of moisture. Typical representatives of ungulates in the steppes are tours, antelopes, tarpans. However, most of these species economic activity people were exterminated or driven south. In some areas, saigas, which were widely distributed in the past, have been preserved.

Of the rodents, the most common are ground squirrel, vole, jerboa, etc.

The polecat, badger, weasel, and fox also live in the steppe.

Of the birds, the bustard, little bustard, gray partridge, steppe eagle, buzzard, kestrel are typical for the steppes. However, these birds are now rare.

There are much more reptiles than in the forest zone. Among them we single out steppe viper, snake, common snake, nimble lizard, muzzle.

The wealth of the steppes is fertile soils. The thickness of the humus layer of chernozems is more than 1 m. It is not surprising that this natural zone is almost completely developed by man and natural steppe landscapes are preserved only in reserves. In addition to the high natural fertility of chernozems, climate conditions favorable for horticulture, the cultivation of heat-loving grains (wheat, corn) and industrial (sugar beet, sunflower) crops also contribute to agriculture. Due to insufficient precipitation and frequent droughts, irrigation systems have been built in the steppe zone.

The steppes are a zone of developed animal husbandry. Cattle, horses, poultry are bred here. Conditions for the development of animal husbandry are favorable due to the presence of natural pastures, fodder grain, waste from the processing of sunflowers and sugar beets, etc.

Various branches of industry are developed in the steppe zone: metallurgy, mechanical engineering, food, chemical, textile.

Semi-deserts and deserts

In the southeast of the Russian Plain and on Caspian lowland semi-deserts and deserts are located.

The total solar radiation here reaches 160 kcal/cm 2 . The climate is characterized by high air temperatures in summer (+22 - +24 °С) and low in winter (-25-30 °С). Because of this, there is a large annual temperature amplitude. The sum of active temperatures is 3600 °C and more. In the zone of semi-deserts and deserts, a small amount of precipitation falls: an average of up to 200 mm per year. In this case, the moisture coefficient is 0.1-0.2.

The rivers located in the zone of semi-deserts and deserts are fed almost exclusively by the spring melting of snow. A significant part of them flows into lakes or is lost in the sands.

Typical soils of the semi-desert and desert zone are chestnut. The amount of humus in them decreases in directions from north to south and from west to east (this is primarily due to a gradual increase in the sparseness of vegetation in these directions), therefore, in the north and west, the soils are dark chestnut, and in the south - light chestnut ( the content of humus in them is 2-3%. In depressions of the relief, the soils are saline. There are solonchaks and solonetzes - soils, from the upper layers of which, due to leaching, a significant part of the easily soluble salts has been carried away to the lower horizons.

Plants in semi-deserts are usually low, drought-resistant. The semi-deserts of the south of the country are characterized by such plant species as tree-like and clumsy saltwort, camel's thorn, and juzgun. On the hills, feather grass and fescue dominate.

Steppe grasses alternate with patches of wormwood and romance of yarrow.

The deserts of the southern part of the Caspian lowland are the kingdom of semi-shrub polynyas.

For life in conditions of lack of moisture and salinity of the soil, plants have developed a number of adaptations. Solyanka, for example, have hairs and scales that protect them from excessive evaporation and overheating. Others, such as tamarix, kermek, “acquired” special salt-removing glands to remove salts. In many species, the evaporative surface of the leaves has decreased, and their pubescence has occurred.

The growing season for many desert plants is short. They manage to complete the entire development cycle in a favorable time of the year - spring.

The fauna of semi-deserts and deserts is poor compared to the forest zone. The most common reptiles are lizards, snakes, turtles. There are many rodents - gerbils, jerboas and poisonous arachnids - scorpions, tarantulas, karakurts. Birds - bustard, little bustard, lark - can be seen not only in the steppes, but also in semi-deserts. Of the largest mammals, we note the camel, saiga; there is a corsac, a wolf.

A special area in the zone of semi-deserts and deserts of Russia are the Volga delta and the Akhtuba floodplain. It can be called a green oasis among the semi-desert. This territory stands out for its thickets of reed-bulrush (it reaches a height of 4-5 m), shrubs and shrubs (including blackberries), intertwined with climbing plants (hops, bindweed). In the backwaters of the Volga delta there are many algae, white water lilies (including the Caspian rose and water chestnut preserved from the pre-glacial period). Among these plants there are many birds, among which herons, pelicans and even flamingos stand out.

The traditional occupation of the population in the zone of semi-deserts and deserts is cattle breeding: they breed sheep, camels, and cattle. As a result of overgrazing, the area of ​​unfixed windblown sands is increasing. One of the measures to combat the onset of the desert is phytomelioration - a set of measures for the cultivation and maintenance of natural vegetation. To fix the dunes, plant species such as giant grate, Siberian wheatgrass, and saxaul can be used.

Tundra

Huge expanses of the coast of the Arctic Ocean from the Kola Peninsula to the Chukotka are occupied tundra. The southern border of its distribution is practically owls
falls e by the July isotherm of 10 °C. Farthest to the north, the southern border of the tundra moved away in Siberia - north of 72 ° N. In the Far East, the influence of cold seas has led to the fact that the tundra border reaches almost the latitude of St. Petersburg.

The tundra receives more heat than the polar desert zone. The total solar radiation is 70-80 kcal/cm2 per year. However, the climate here continues to be characterized by low air temperatures, short summers, and severe winters. The average air temperature in January reaches -36 °С (in Siberia). Winter lasts 8-9 months. At this time of the year, southerly winds blowing from the mainland dominate here. Summer is characterized by an abundance of sunlight, unstable weather: strong northern winds often blow, bringing cooling and precipitation (especially in the second half of summer there are often heavy drizzling rains). The sum of active temperatures is only 400-500 °C. The average annual rainfall reaches 400 mm. Snow cover lasts 200-270 days a year.

The predominant types of soils in this zone are peat-bog and weakly podzolic. Due to the spread of permafrost, which has a water-resistant property, there are many swamps here.

Since the tundra zone has a significant length from north to south, within its limits, climatic conditions change markedly: from severe in the north to more moderate in the south. In accordance with this, arctic, northern, they are also typical, and southern tundras are distinguished.

arctic tundra occupy mainly the arctic islands. The vegetation is dominated by mosses, lichens, there are flowering plants, in comparison with the Arctic deserts there are more of them. Flowering plants are represented by shrubs and perennial herbs. Polar and creeping willow, dryad (partridge grass) are common. Of the perennial grasses, the most common are the polar poppy, small sedges, some grasses, and saxifrage.

northern tundra distributed mainly on the mainland coast. Their important difference from the arctic ones is the presence of a closed vegetation cover. Mosses and lichens cover 90% of the soil surface. Green mosses and bushy lichens predominate, moss is often found. The species composition of flowering plants is also becoming more diverse. There are saxifrages, ozhiki, highlander viviparous. Of the shrubs - lingonberries, blueberries, ledum, crowberry, as well as dwarf birch (dwarf birch), willows.

AT southern tundra, as in the northern ones, the vegetation cover is continuous, but it can already be divided into tiers. The upper tier is formed by dwarf birch and willows. Medium - herbs and shrubs: crowberry, lingonberry, blueberry, wild rosemary, sedge, cloudberry, cotton grass, cereals. Lower - mosses and lichens.

The harsh climatic conditions of the tundra "forced" many plant species to "acquire" special adaptations. So, plants with creeping and creeping shoots and leaves collected in a rosette better "use" a warmer ground layer of air. Short stature helps to survive the harsh winter. Although due to strong winds The thickness of the snow cover in the tundra is small, it is enough to take cover and survive.

Some devices "serve" plants in the summer. For example, cranberries, dwarf birch, crowberry “fight” for moisture retention by “reducing” the size of the leaves as much as possible, thereby reducing the evaporating surface. In the dryad and the polar willow, the underside of the leaf is covered with dense pubescence, which impedes the movement of air and thereby reduces evaporation.

Almost all plants in the tundra are perennial. For some species, the so-called live birth is characteristic, when instead of fruits and seeds, bulbs and nodules appear in the plant, which quickly take root, which provides a “gain” in time.

Animals and birds permanently living in the tundra have also adapted well to the harsh natural conditions. They are saved by thick fur or fluffy plumage. In winter, animals are white or light gray in color, and in summer they are grayish-brown. It helps to disguise.

Typical animals of the tundra are arctic fox, lemming, white hare, reindeer, snowy and tundra partridge, snowy owl. In summer, the abundance of food (fish, berries, insects) attracts such birds as waders, ducks, geese, etc. to this natural area.

The tundra has a relatively low population density. The indigenous peoples here are the Saami, Nenets, Yakuts, Chukchi, etc. They are mainly engaged in reindeer herding. The extraction of minerals is actively carried out: apatites, nephelines, non-ferrous metal ores, gold, etc.

Railway communication in the tundra is poorly developed, and permafrost is an obstacle to the construction of roads.

forest tundra

forest tundra- transitional zone from tundra to taiga. It is characterized by the alternation of areas occupied by forest and tundra vegetation.

The climate of the forest-tundra is close to the climate of the tundra. The main difference: the summer here is warmer - the average July temperature is + 11 (+14) ° С - and long, but the winter is colder: the influence of the winds blowing from the mainland affects.

The trees in this zone are stunted and bent to the ground, with a twisted appearance. This is due to the fact that permafrost and waterlogging of the soil do not allow plants to have deep roots, and strong winds bend them to the ground.

In the forest-tundra of the European part of Russia, spruce predominates, and pine is less common. In the Asian part, larch is common. Trees grow slowly, their height usually does not exceed 7-8 m. Due to strong winds, a flag-shaped crown shape is common.

The few animals that remain in the forest-tundra to spend the winter are perfectly adapted to local conditions. Lemmings, voles, tundra partridge make long passages in the snow, feed on the leaves and stems of evergreen tundra plants. With an abundance of food, lemmings even bring offspring at this time of the year.

Animals from the forest zone enter the southern regions through small forests and bushes along the rivers: mountain hare, brown bear, ptarmigan. There are wolf, fox, ermine, weasel. Small insectivorous birds fly in.

Subtropics

This zone, which occupies the Black Sea coast of the Caucasus, is characterized by the smallest length and area in Russia.

The value of total solar radiation reaches 130 kcal/cm2 per year. Summer is long, winter is warm (average January temperature is 0 °C). The sum of active temperatures is 3500-4000 °C. In these conditions, many plants can develop all year round. In the foothills and on the mountain slopes, 1000 mm or more of precipitation falls annually. In the flat areas, snow cover is practically not formed.

Fertile red earth and yellow earth soils are widespread.

Subtropical vegetation is rich and varied. The flora is represented by evergreen hard-leaved trees and shrubs, among which we will name boxwood, laurel, laurel cherry. Widespread forests of oak, beech, hornbeam, maple. Thickets of trees intertwine liana, ivy, wild grapes. There are bamboo, palm trees, cypress, eucalyptus.

Of the representatives of the animal world, we note the chamois, deer, wild boar, bear, pine and stone marten, Caucasian black grouse.

The abundance of heat and moisture makes it possible to grow such subtropical crops here as tea, tangerines, and lemons. Significant areas are occupied by vineyards and tobacco plantations.

Favorable climatic conditions, proximity to the sea and mountains make this area a major recreational area of ​​our country. Numerous camp sites, rest houses, sanatoriums are located here.

In the tropical zone are moist forests, savannas and woodlands, deserts.

Largely open tropical rainforests(South Florida, Central America, Madagascar, Eastern Australia). They are used, as a rule, for plantations (see map of the atlas).

The subequatorial belt is represented by forests and savannahs.

Subequatorial moist forests located mainly in the Ganges valley, southern Central Africa, on the northern coast of the Gulf of Guinea, northern South America, in Northern Australia and on the islands of Oceania. In drier areas they are replaced savannas(Southeast Brazil, Central and East Africa, central regions Northern Australia, Hindustan and Indochina). Characteristic representatives of the animal world subequatorial belt- ruminant artiodactyls, predators, rodents, termites.

At the equator, an abundance of precipitation and high temperatures led to the presence of a zone here evergreen rainforests(Amazon and Congo basin, on the islands of Southeast Asia). The natural area of ​​evergreen moist forests holds the world record for the diversity of animal and plant species.

The same natural areas are found on different continents, however, they have their own characteristics. First of all, we are talking about plants and animals that have adapted to the existence in these natural areas.

The natural zone of the subtropics is widely represented on the coast mediterranean sea, the southern coast of Crimea, in the southeast of the United States and in other regions of the Earth.

Western Hindustan, Eastern Australia, the Paraná basin in South America and South Africa are areas of distribution of more arid tropical savannas and woodlands. The most extensive natural zone of the tropical belt - desert(Sahara, Arabian desert, deserts of Central Australia, California, as well as the Kalahari, Namib, Atacama). Huge expanses of pebbly, sandy, rocky and saline surfaces are devoid of vegetation here. The animal world is small.

In order to answer this question, you need to know the following:

• geographical location Crimean peninsula;
• what are natural areas and what they are;
• what are thermal zones and what they are.

What natural areas exist

Natural zones are called certain parts of the earth's surface, which have significant differences in various indicators, namely: natural conditions, temperature regime, vegetation, animal world And so on.

There are many natural zones that start from the Antarctic and Arctic deserts, where low temperatures and permafrost prevail, tundra, deserts and steppe forests. As well as constantly and variable-moist forests, which have very rich vegetation and high temperatures. However, these are far from all natural areas that exist on the planet.

Using a map of the natural zones of the world or Russia, you can answer the question. Thus, the main place on the Crimean peninsula is occupied by the natural zone of steppes and forest-steppes.

Thermal belts and their differences

Thermal zones are called separate parts of the globe, which differ in their average temperature throughout the year.

There are several thermal zones. The cold belts of the Northern and Southern Hemispheres, because Since they are as far as possible from the equator of the planet, the Sun warms them up the least, and as a result, the lowest temperature.

The temperate zones of the Northern and Southern Hemispheres warm up quite well in summer, however, in winter it is quite cool there due to lack of sunlight.

The hot belt is located on both sides of the equator and is the warmest place on the planet in both summer and winter.

Having considered thermal zones both theoretically and on the map, and also knowing geographical position Crimean peninsula, we can conclude that the southern part of the Crimean peninsula is located in the temperate thermal zone. And its rest belongs more to the hot thermal zone. This is due to the difference in temperatures in winter and summer, as well as proximity to the equator.

Studying the geography of Russia
by natural areas

The course offers new, or firmly forgotten old, approaches to the study of the traditional Russian geography course. It was in natural areas that the geography of the USSR was taught in the 4th grade in the pre-war and first post-war years. At the same time, it was told not only about nature, but also about the population and economy of the country. Such an approach will make it possible to put already known and newly studied theoretical concepts on a factual basis, to link nature with the economy. In the content part of the course, a simple style of presentation is deliberately used so that this material can be used in any class according to the level of preparedness.

The study of geography by natural areas provides for the consideration of population and production in close connection with natural conditions and resources. By zones, human impact on the environment, the ability to improve natural conditions and compensate for damage to nature are also assessed.

ACADEMIC PLAN

LECTURE 1

Zones and belts
as the basis for zoning Russia

Russia, which occupies a huge space in the north of Eurasia, is not only the largest, but also the northernmost country in the world. It contains the northernmost continental point on Earth.

Ask students the following questions.

Canada is considered a northern country.

1. Compare the latitude of the northernmost continental points of Canada and Russia.

2. Compare the latitude of the northernmost island points of these countries.

3. Compare the latitudes of the southern points of these countries.

4. The US-Canada border runs parallel for a long distance. Determine the latitude of this parallel. What large city in Russia is located at the same latitude? Is it considered a northern or southern city for Russia?

The results of these measurements can be represented graphically (Fig. 1). Sufficient measurement accuracy in all these tasks is half a degree.

Norilsk, a city with a population of 180,000, is located at a latitude of 69.5°. Where else at this latitude or further north are cities with the same or greater population?

Murmansk, latitude 69°, 430 thousand people.

St. Petersburg, latitude 60°, 5 million people.

Moscow, latitude 56°, 10 million people.

Ask the same question that applied to Norilsk in relation to Murmansk, St. Petersburg and Moscow. The answer will be the same everywhere: the same in terms of population or larger cities for the same or more northern latitudes no.

Russia occupies the northern part of Eurasia - the eastern third of Europe and the northern third of Asia (Fig. 2). Within Russia are the northern and eastern extreme continental points of the mainland; both are in Asia. The mainland is most elongated from west to east in its northern part, that is, within Russia.

Natural zoning is taken as the basis for zoning in this course. In the future, we will clarify to what extent the zones can be considered natural, and in which zones nature has been so altered by man that we have to talk about natural economic zones.

Zoning

A natural combination in any territory of relief, climate, surface and groundwater, soils, biocenoses is called natural territorial complex; the common abbreviation for this term is PTK. The term is also widely used to refer to the same concept. landscape(German Landschaft- terrain). The branch of physical geography that studies natural territorial complexes is called landscape science. However, different experts understand the term "landscape" in different ways, and hopes that in the foreseeable proximity they will come to consensus, No. It is possible to consider the NTC of different levels - from small characteristic areas of the earth's surface to the geographical envelope, which is a global NTC.

This multi-level nature of territorial complexes in many respects complicates their perception at school. We will use only one of these levels - natural areas, which, as experience has shown, are perceived by schoolchildren more easily than other generalizing concepts.

One of the fundamental laws of physical geography is law of geographic zoning, which is that due to the uneven distribution of the radiant energy of the Sun over latitudes and uneven moistening, the entire complex of natural conditions and their individual components consistently and definitely change in latitudes, on the whole symmetrically with respect to the equator. As a result, there are natural areas(Greek zone - belt) - vast areas with close climatic conditions, first of all, by temperatures and moisture, which determine generally homogeneous soils, vegetation and wildlife.

On the plains, the zones are elongated, as a rule, along the parallels, latitudinally. Zonal vegetation, soils and wildlife create a certain appearance of the area. Zoning was noted by ancient geographers, and the first strict formulation of the law belongs to V.V. Dokuchaev. The names of the zones are given according to their most physiognomic feature - the predominant type of vegetation: steppe, forest, tundra zones, etc.

Natural conditions are determined by many factors, some of which are zonal, others azonal(here there is a Greek negative prefix a-).

The geological structure is azonal. It influences geographical conditions mainly indirectly, through relief and partly through soils.

The relief, to the extent that it is predetermined by the geological structure and tectonic movements, is azonal. External (exogenous) processes of relief formation are largely determined by climate (glacier activity; processes associated with permafrost; wind transport and deposition of sand, etc.), therefore, the relief also has zonal features, although zonal, as a rule, are not large landforms , and those complicating them are small.

In some cases, the main factors in the formation of natural conditions are not zonal, but local factors - the nature rocks, inflow and outflow of moisture, etc. For example, in several adjacent zones, floodplain meadows, pine forests on the sands, swamps. This phenomenon is called intrazonal(Latin prefix intra- - inside).

In the ocean, zoning is also traced, although for the observer it is much less obvious than on land.

In the mountains, the latitudinal zonality common to the plains gives way to altitudinal zonality.

How is zoning defined?

Usually, zoning is considered as something primary, predetermined. Meanwhile, it is the result of the interaction of many factors related to latitude, but by no means limited to the well-known thesis: closer to the equator - warmer(for the Northern Hemisphere it can be shorter: south is warmer). Ultimately, zoning is determined by climate. The climate of Russia is determined mainly by the fact that it

Lies in high latitudes;

It occupies a vast area within the largest continent, there are places in the country that are very far from the ocean;

Open to the north, to the Arctic Ocean, and from warm southern countries fenced off by mountains.

Let us recall the belts distinguished on the Earth according to various criteria. The distribution of heat on the globe depends on many factors, but in the most in general terms it is certainly determined by latitude, so that the position of the territory relative to lighting belts already to a large extent shows what kind of climate there is. Illumination belts are defined by slope earth's axis with respect to the plane of the orbit. The border between the polar and temperate zones of illumination runs along the Arctic Circle - a parallel with a latitude of 66.5 °. To the north of the Arctic Circle there are polar days in summer, and polar nights in winter - the longer the closer to the pole.

The northern part of the territory of Russia lies beyond the Arctic Circle, there are polar day and polar night. White nights occur in summer at a distance of 6-7 ° latitude from the Arctic Circle, at latitudes of 60 ° and higher, that is, in a very significant part of the territory of Russia. Beyond the Arctic Circle, the white nights precede the onset of the polar day; after its completion, white nights are also observed for some time.

Above the polar circles, up to a latitude of about 73°, it dawns around noon in winter, although the Sun does not rise. In Murmansk (69°N), you can freely walk the streets, street lighting is turned off.

Russia does not reach the Northern Tropic very far, so the Sun at its zenith does not happen on our territory.

Give students a task.

In a day summer solstice The sun at noon is at its zenith over the Tropic of the North. At what angular distance from the zenith will it be on this day at the southern point of Russia? In your locality? (Obviously, the same number of degrees as the point in question is from the Tropic of the North.)

More accurately characterizes the climate of any place, its position relative to thermal zones. The boundaries between them are drawn along isotherms.

The boundary of the belt of eternal frost and the cold belt is the 0 °C isotherm of the warmest month. In the zone of eternal frost, the temperature at some moments can rise above zero, but the average monthly temperature is always negative. The isotherm of the warmest month is in most cases July; but water has a colossal heat capacity, it warms up slowly, and in some places the maximum can pass into August. A significant part of the Arctic Ocean is located in this belt; Russia owns small polar islands here.

The cold belt is also limited from the south by the isotherm of the warmest month - July, with a possible transition to August, 10 ° C. All the large Arctic islands of Russia and the north of its mainland, including the Yamal, Taimyr, and Chukotka peninsulas, lie in the cold belt (Fig. 3); there are also small areas where the July isotherm of 10 °C also passes at lower latitudes, but we will not take these areas in the mountains into account.

The rest of Russia is located in the northern temperate zone. The average annual temperature of one of the warmest cities in Russia, Sochi, is about 16 ° C, that is, it is still quite far from the temperatures of the hot zone; in most of the European territory of the country, it does not reach even 5 degrees, and in the Asian it is predominantly negative.

There is a system of belts associated with the general circulation of the atmosphere. When studying this topic at school and at the university, these belts are talked about, but there is no generally accepted name for this system of belts; let's call them atmospheric pressure belts. Meanwhile, these belts, along with thermal belts, form the basis for the emergence of air masses of various types, on which the classification of climates is built.

Table 1

Atmospheric pressure belt system

The system is built on the basis of an unrealistic assumption about the uniformity of the underlying surface on Earth. The location of the continents and oceans, the relief of the earth's surface distort the picture very much, the boundaries between the belts are fuzzy, there are transitional areas. However, the objective existence of belts is beyond doubt.

On the basis of thermal belts and belts associated with the general circulation of the atmosphere, a system was built climatic zones.

There are several classifications of climates. Of these, the classification created by Moscow University professor Boris Pavlovich A "lisov is the most widespread in Russia. It is based on the fact that there are several types of air masses that differ in the place of their formation - arctic (in the southern hemisphere - antarctic), temperate, tropical and equatorial.They are clearly related to the atmospheric pressure belts - in the order in which they are listed in table 1.

Table 2 shows only those climatic zones that are on the territory of Russia.

table 2

Climatic zones of Russia
according to B.P. Alisov

Note. AB - arctic air, VSH - air of temperate latitudes, TV - tropical air.

Air masses that are uncharacteristic for it in general or in a given season can also invade the belt for a short time. Thus, residents of Moscow, located in the temperate zone, are sometimes affected by alien air masses: in winter, severe frosts are caused by arctic air, which usually comes from the northeast, and in summer, tropical air masses can cause hot and dry weather, especially since they are not far away. - during this season they can form over the territory of Central Asia and Kazakhstan.

The position of Russia in the system of climatic zones can be seen on the map of climatic zones and regions in the atlas for the 7th grade.

To arctic belt Russia includes almost all the Arctic islands and a strip of the continental margin of the Asian part of the country from Yamal to Chukotka, in few places exceeding 500 km in width.

The subarctic belt begins in the west as a narrow strip along the coast of the Kola Peninsula, expands to the east, its southern border runs south of the mouth of the Ob and then goes almost along the shortest line to Sea of ​​Okhotsk. In the east, the width of the belt exceeds
1000 km.

Almost the rest of the territory of Russia lies in the temperate climatic zone, differing quite significantly in the degree of continentality of the climate, in the influence of the oceans on the climate.

On the Black Sea coast of the Caucasus there is a small area with a subtropical climate.

natural areas

Eurasia has all the natural zones that are found on the globe. Of these, in Russia there are arctic desert, tundra, taiga, mixed forests, steppes, deserts of the temperate zone and subtropics, as well as transitional zones between the above. The areas occupied by subtropics and deserts are very small. Some believe that the most arid regions of Russia should be classified as dry steppes; in the future, arguments will be given in favor of the fact that there are deserts in Russia.

Mountains occupy a smaller part of Russia. But the area of ​​territories where latitudinal zonality is replaced by altitudinal zonality or combined with it is still very large, no less than 4 million km2.

The general ratio between belts and zones on the territory of Russia can be represented as follows (Table 3).

In the atlas for grades 8-9 there is a map of the vegetation of Russia. On it, the types of vegetation are given in much more detail than by zones, so the zones are hard to read. It is better to use a map of the natural zones of Eurasia in the atlas for the 7th grade or maps of the natural zones of Russia in the atlas of natural history.

Table 3

Belts and zones in Russia

population and large areas Russia

In European Russia and the Caucasus, that is, on 30% of the country's territory, 3/5 of its population lives. In other words, the average population density to the west of the Urals is much greater than to the east. The main feature of the composition of the population of Russia is its multinationality. The 2002 census recorded over 160 nationalities. Russians make up 80% of the population. Only in most of European Russia, the Russians are the indigenous population, who lived there almost always, they came to other places when other peoples already lived there. But now the Russians in many of these areas are the majority and have long been considered the indigenous population. The second largest people in Russia are Tatars (3.8%), followed by Ukrainians, Bashkirs, Chuvashs, Chechens, Armenians, Mordovians, Avars, Belarusians, Kazakhs, Udmurts, Azerbaijanis, Maris, Germans, Kabardians, Ossetians, Dargins, Buryats, Yakuts, Kumyks, Ingush, Lezgins (0.3%). All other peoples together make up less than 3% of the population.

Most of the listed peoples have their own national-territorial formations within Russian Federation. Ukrainians, Armenians, Belarusians, Kazakhs and Azerbaijanis make up the main population of the five former republics of the USSR. The Germans stand apart, of which there were always many in Russia and the USSR, at times up to two million (about 0.8% of the population of the USSR), but the departure to their historical homeland, assimilation, and also the fact that a significant part of the Germans who lived in the USSR are now in Kazakhstan; Germans make up 0.4% of the Russian population.

When characterizing both the nature of Russia and its population and economy, large parts of it are usually distinguished: European Russia, the Caucasus, the Urals, Siberia, and the Far East.

This zoning was carried out on various grounds.

European Russia is mostly flat. Latitudinal zonality is most fully represented here, all the zones that are in Russia are also in European Russia, only the Arctic deserts are not on the mainland, they are located on the islands. On the Russian Plain, the Russian nation and the core of Russian state, the main part of the country's economy is concentrated here.

The Caucasus includes the plains of Ciscaucasia and the Caucasus Mountains proper. In the Caucasus Mountains, the altitudinal zonality is better than anywhere else in Russia. The Caucasus has been inhabited since ancient times, but became part of Russia only about 200 years ago.

The Urals separate European Russia and Siberia. The region called the Urals includes both the Ural Mountains themselves and the lands on either side of them. The Urals was the first major ore base and the first area of ​​heavy industry in the country.

Siberia is the entire trans-Ural part of Russia, except for the basins of the rivers flowing into the Pacific Ocean and its seas. Siberia is very large, its area is approximately equal to the area of ​​Canada or China. Due to the vast area of ​​Siberia, it is difficult to consider it as a single natural area. Rather, we single out Siberia because for Russia, along with the Far East, this is a territory of relatively late development. This, as well as the harsh natural conditions of Siberia, explains both the low population density and the relatively small disturbance of the natural environment.

The Far East is a territory that includes the basins of rivers flowing into the Pacific Ocean. The main feature of the Far East is that most of its geographical features are due to the proximity of the Pacific Ocean, which is manifested in everything - in relief and tectonics ("Pacific Ring of Fire"), in climate, in direct connection with the countries lying on the shores of the Pacific Ocean .

QUESTIONS and TASKS

1. Can the southern boundary of the cold belt not coincide with the 10 °C isotherm plotted in Figure 3? Justify the answer.

2. Formulate the main features by which large regions of Russia are distinguished. (In some cases, two features are possible for the same region.)

3. Calculate how many times the average population density in European Russia is higher than in Asian Russia.

4. Based on table 3, select natural zones that exactly correspond to one climatic zone, and zones located in two neighboring climatic zones. Do the same for the lighting and heat zones.

Natural conditions in different parts of the globe are not the same, but naturally change from the poles to the equator. The main reason for this is the spherical shape of the Earth. Indeed, if the Earth were flat, like a blackboard, its surface, oriented (directed) strictly across the sun's rays, would heat up equally everywhere, both at the poles and at the equator.

But our planet has the shape of a ball, which is why the sun's rays fall on its surface at different angles, and therefore heat it differently. Above the equator, the sun “looks” at the earth’s surface almost “point-blank” during the day, and twice a year, at noon, its hot rays fall here at a right angle (the sun in such cases is at its zenith, i.e. directly overhead) . At the poles, the sun's rays fall obliquely, at an acute angle, the sun for a long time moves low above the horizon, and then does not appear at all in the sky for several months. As a result, the equator and even temperate latitudes receive much more heat than the regions near the poles.

Therefore, in both hemispheres of the Earth, several thermal zones are distinguished: equatorial, two tropical, two temperate and two cold. Solar heat is driving force natural processes and phenomena that we observe around us in the surface shell of the Earth. Now scientists call this shell the biosphere, that is, the sphere of life.

And since solar heat is unevenly distributed on Earth, then in the biosphere, in the nature around us, large differences are clearly expressed from one thermal zone to another. Accordingly, geographic zones are already distinguished. Their boundaries coincide with the boundaries of thermal zones.

But in each of geographical zones natural conditions are different. After all, the width of these belts in places is more than 4 thousand km. km! The closer to the equator one or another part of the geographic zone, the more heat it receives and the more it differs from other parts remote from the equator. Such differences are especially pronounced in climate, soils, vegetation and wildlife. Therefore, within the geographical zones, geographical, or natural, zones are clearly expressed, that is, areas more or less homogeneous in terms of natural conditions. They stretch most often in a strip along the parallels. So, in temperate zones, zones are distinguished: forest, forest-steppe, steppe, semi-desert and desert.

The distribution of natural zones around the globe and their boundaries are determined not only by the amount of solar heat. Of great importance is the amount of moisture, which is also unevenly distributed on land. This leads to large differences in natural conditions even at the same latitude. In Africa, there is a lot of heat everywhere near the equator, but on the west coast, where there is also a lot of moisture, dense tropical forests grow, and on the east, where it is not enough, there are savannahs, sometimes quite dry.

In addition, to the position geographical areas landmasses are influenced by mountain ranges that change the direction of the zones along the parallels. The mountains have their own high-altitude zones, as it gets colder with the rise. At high altitudes, the earth's surface gives off a lot of heat to the surrounding space, "supplied" to it by the sun. This happens because the air above is rarefied, and although here it transmits more sunlight than at the foot of the mountains, the loss of heat from the earth's surface increases with height to an even greater extent.

Altitude zones occupy smaller spaces than plain zones (latitudinal), and seem to repeat them: mountain glaciers - the polar zone, mountain tundra - tundra, mountain forests - the forest zone, etc. The lower part of the mountains usually merges with that latitudinal zone, within which they are located. So, for example, taiga approaches the foothills of the Northern and Middle Urals, at the feet of some mountains of Central Asia, which lie in the desert zone, a desert spreads, and in the Himalayas the lower part of the mountains is covered with tropical jungle, etc. The largest number high-altitude zones (from glaciers on mountain tops to rainforest at the foot) is observed in high mountains located near the equator. Altitude zones, although similar to the plains, but the similarity is very relative.

Indeed, the amount of precipitation in the mountains usually increases with height, while in the direction from the equator to the poles it generally decreases. In mountains with height there is no such change in the length of day and night as when moving from the equator to the poles. In addition, climatic conditions become more complicated in the mountains: here the steepness of the slopes and their exposure (northern or southern, western or eastern slopes) play a significant role, special wind systems arise, etc. All this leads to the fact that both soils and the vegetation and fauna of each altitudinal zone acquire special features that distinguish it from the corresponding flat zone.

Differences in natural zones on land are most clearly reflected by vegetation. Therefore, most of the zones are named after the type of vegetation that prevails in them. These are the zones of temperate forests, forest-steppes, steppes, tropical rainforests, etc.

Geographical zones can also be traced in the oceans, but they are less pronounced than on land, and only in the upper layers of water - up to a depth of 200-300 m. Geographical zones in the oceans generally coincide with thermal zones, but not completely, since water is very mobile, sea currents constantly mix it up, and in some places transfer it from one zone to another.

In the oceans, as well as on land, seven main geographical zones are distinguished: equatorial, two tropical, two temperate and two cold. They differ from one another in temperature and salinity of water, the nature of currents, vegetation and wildlife.

So, the waters of cold zones have a low temperature. In them, somewhat less than in the waters of other zones, there are dissolved salts and more oxygen. The vast expanses of the seas are covered powerful ice, and the flora and fauna are poor in species composition. In temperate zones, the surface layers of water heat up in summer and cool down in winter. Ice in these zones appears only in places, and even then only in winter. organic world rich and varied. Tropical and equatorial waters are always warm. Their life is abundant. What are geographic land areas? Let's get acquainted With the most important of them.

Ice is a natural zone adjacent to the poles of the globe. In the northern hemisphere to ice zone include the northern outskirts of the Taimyr Peninsula, as well as numerous islands of the Arctic - areas lying around North Pole, under the constellation Ursa Major ("arktos" in Greek - bear). These are the northern islands of the Canadian Arctic Archipelago, Grenland of the day, Svalbard, Franz Josef Land, etc.

In the southern polar region - Antarctica (from the Greek word "anti" - against, that is, against the Arctic) - there is an ice-covered continent of Antarctica, which is part of the ice zone of the southern hemisphere.

The harsh nature of the ice zone. Snow and ice do not melt here completely even in summer. And although the sun shines for several months without interruption, around the clock, it does not warm the earth, which has cooled down during the long winter, as it rises low above the horizon. In addition, the sun is often covered with thick clouds and fogs, and the white surface of snow and ice reflects its rays. On the polar night, severe frosts rage.

In 1961, Soviet researchers of Antarctica had to work at frosts of 88.3°. At the same time, hurricane winds were still blowing - up to 70 m/sec. In motors, because of such low temperatures, gasoline did not catch fire, and metal and rubber became brittle, like glass.

Summer is coming over arctic desert the sun is rising, it will not hide behind the horizon for a long time. And yet clear sunny weather happens infrequently. The sky is overcast with low clouds, it rains for several days in a row, and even snow. There are very few plants here: the conditions are too harsh. Ice fields covered with snow are spread everywhere, and bare rocks and stony placers darken on the islands and the coast. Even where ice and snow do not interfere with plants, strong winds destroy them. Only in places, in the lowlands protected from ice breathing, do small “oases” manage to form in a short summer. But here, too, the plants do not stretch upwards, but press against the ground: it is easier for them to stand against the wind. As soon as the snow melts, the first flowers appear. They develop very quickly, because the sun shines around the clock.

In the most favorable conditions of the icy desert of the Arctic, there are patches of arctic meadows and marshes. On the island of Svalbard, polar poppies turn yellow. More than thirty species of flowering plants are found in the flora of Franz Josef Land. Even in the icy expanses of the central part of Greenland, red-brown or green fields formed by microorganisms can be seen from an airplane.

Noisy in summer in the Arctic. Return to their nests migratory birds: little auks, guillemots, guillemots, various gulls ... There are not so many species, but each is represented by many thousands of birds. They nest on ledges of coastal cliffs in huge colonies, making a terrible noise. That is why these colonies are called "bird colonies". How to explain the desire of birds to settle in such huge numbers in small areas? The fact is that steep cliffs with ledges, small platforms are very convenient for nesting, and nearby there is an abundance of fish that birds feed on. In addition, together it is easier to drive away the predator.

Other birds also fly to the Arctic: geese, terns, eiders. In spring, the eider grows a long fluff on its abdomen, with which it covers its nest. This fluff is unusually warm and light and therefore highly valued. People collect it on eider nesting sites and even arrange artificial nests for it in the form of a half-open box.

In Greenland and on the islands of the Canadian Arctic archipelago, an animal has survived, whose ancestors lived back in the days of mammoths and long-haired rhinos. This is a wild musk ox, or musk ox. It really resembles both a ram and a bull at the same time. Its massive body is covered with long hair.

The nature of the Antarctic is even poorer than the Arctic. The average height of Antarctica is 2200 m above sea level, but the earth's surface is much lower here, because it is hidden under a thick layer of ice, its average thickness is more than 1500 m, and the largest is 5000 m. Sparse vegetation is found here only on the coast of the mainland. These are mainly mosses and lichens. Only three species of flowering plants are known here. Not rich in species and the Antarctic fauna. There are no such large animals as the polar bear. Seals live off the coast of Antarctica, and petrels and albatrosses fly over the oceans washing it. Albatross wingspan up to 4 m. These birds spend most of their lives above the water, catching fish.

The most remarkable animals of Antarctica are penguins. These birds have lost the ability to fly, their wings have turned into swimming flippers. Penguins are excellent swimmers and divers. And on land they are clumsy, waddling, while resembling fat funny little men in black tailcoats and white shirts. Penguins nest in numerous colonies. Their only enemy is the sea leopard (one of the species of local seals).

For a long time, the Arctic and especially the Antarctic were almost undeveloped by man. Now, thanks to the achievements of science and technology, we can already talk not only about the study and use of these little-studied areas, not only about the adaptation of man to their harsh natural conditions, but also about the influence of man on the nature of the ice zone.

At high altitudes in the mountains it is as cold as in the ice zone, the same wind-blown stones, only in some places covered with mosses and lichens. But there are no sea spaces nearby, migratory birds do not arrange “bazaars”. There are no many months of polar days and nights here. At high mountains, atmospheric pressure is low, the air is poorer in oxygen, so not all animals can adapt to life in high mountain conditions. Tolerates cold and altitude well large predator- Snow Leopard. The whitish shade of the fur makes it hardly noticeable against the background of snow and gray stones. In summer, the leopard usually stays on the line of eternal snows, and in winter it descends lower, following its prey - mountain sheep and mountain turkeys (ulars).

The more grass in the steppe, the more large herbivores. And the more predators. In our steppes, the characteristic predator is the wolf (although it is also found in other zones), and in the North American steppes, small wolves are coyotes.

Of the steppe birds, only the bustard and the gray partridge live settled, not flying away to warm countries for the winter. But in the summer, many representatives of the feathered kingdom settle in the steppe: ducks, waders, demoiselle crane, larks.

At a great height above the steppe, raptors soar: eagles, vultures, etc. Open spaces allow them to notice prey from above at a distance of several kilometers. Birds of prey sit down to rest on mounds, telegraph poles and other elevations, from where it is better to see and easier to take off.

The steppes of North America are called prairies. In them, along with plants common to our steppes (feather grass, wheatgrass), there are those that are not in the eastern hemisphere: bison grass, Graam grass, etc. The steppes of South America, pampa, are even more diverse.

Rigid grasses a meter - one and a half high in places completely cover large areas of the pampas. Where the soil is somewhat wetter, bright green creepers appear, and with them - scarlet, pink, white verbena. Yellow and white lilies grow in damp places. The most beautiful pampa plant is the silvery hynerium, whose silky panicles seem to have absorbed the most diverse tones of azure sky. In this sea of ​​grass, herds of wild cattle roam, herds of horses, Nandu ostriches stride importantly. Near lakes and rivers, where groves of trees and shrubs meet, one can see black squirrels, tiny hummingbirds, noisy parrots.

In some mountains (Tien Shan, Altai, in the mountains of Transbaikalia, in the Great Khingan, in the Cordillera, etc.) there are places where much resembles a flat steppe. In Central Asia, the mountain steppes almost do not differ from the flat feather grass-fescue steppes.

In ancient times, the steppes occupied vast territories on the plains of North America and Eurasia. Now they are completely open. On fertile steppe soils, wheat, corn, millet, various melons and gourds are grown.

The natural vegetation cover of the steppes is now almost non-existent. The animal world has also changed. The ancestors of our domestic animals have long disappeared here - the wild bull aurochs and wild horses tarpans, some birds have become rare. Now only in a few reserves, in such, for example, as our Askania-Nova, you can see a real virgin steppe.

Subtropical forests and shrubs

Approximately between 30 and 40 ° N. sh. and y.sh. lie the subtropics. Their nature is extremely diverse. Under these latitudes, one can see a lush evergreen forest, and a steppe, and a sultry desert - moisture is so unevenly distributed here - the source of life.

On the western outskirts of the continents there are subtropics, often called Mediterranean, because all the features of their nature are most pronounced on the coasts of the Mediterranean Sea.

Summers in these parts are hot and dry, with rain falling mostly in winter, during which even mild frosts are rare. The vegetation cover of the Mediterranean subtropics is dominated by thickets of evergreen shrubs and low trees. A noble laurel, a strawberry tree that annually sheds its bark, tender myrtle, wild olives, roses, and junipers grow here. In many plants that have adapted to the dry summer, the leaves have turned into thorns. Entwined with the same prickly vines, they become an insurmountable obstacle for travelers.

When it's time to bloom, the bushy thickets (they are called maquis) turn into a sea of ​​​​luxurious flowers - yellow, white, blue and red. A strong aroma spreads in the surrounding air.

One of the most beautiful plants Mediterranean subtropics - Italian pine, or pine. The wide, sprawling crowns of pines seem especially magnificent in the neighborhood with dense, spindle-shaped crowns of cypresses. These grow lovely trees most often alone. Very few pine groves have survived. Small forests, which can still be found in the Mediterranean subtropics, consist mainly of evergreen oaks - cork and holm. Trees rarely stand here, and grasses and shrubs grow wildly between them. In such a forest there is a lot of light, and in this way it differs greatly from the shady Russian oak forests.

A different picture is presented by the subtropics on the eastern outskirts of the continents. In southeastern China and southern Japan, precipitation is also uneven, but it only rains more in summer (and not in winter, as in the Mediterranean subtropics), i.e., at a time when vegetation is especially in need of moisture. Therefore, dense moist forests of evergreen oaks, camphor laurel, and magnolias grow here. Numerous creepers entangling tree trunks, thickets of tall bamboos and various shrubs enhance the originality of the subtropical forest.

In the southeastern part of the United States dominated by swampy subtropical forests, consisting of american species pine, ash, poplar, maple. Swamp cypress is widespread here - a huge tree reaching 45 m tall and 2 m across. In Russia, the subtropics include the Black Sea coast of the Caucasus, the Lankaran lowland on the Caspian coast. The subtropics are the birthplace of valuable cultivated plants: oranges, tangerines, lemons, grapefruits, persimmons, etc. In addition to citrus fruits, olives, laurel cherries, figs, pomegranates, almonds, date palms and many others are grown here. fruit trees and shrubs. See also: .

desert

Deserts occupy vast territories on the globe, especially in Asia, Africa and Australia. Their total area is estimated at 15-20 million hectares. km 2 . There are deserts of the temperate zone, subtropical and tropical.

In the temperate zone, all the plains of Asia, from the Caspian Sea in the west to Central China in the east, are almost entirely desert spaces. In North America, some intermountain depressions in the west of the mainland are deserted.

Subtropical and tropical deserts are located in the north-west of India, in Pakistan, Iran, Asia Minor. They cover the Arabian Peninsula and the entire north of Africa, the western coast of South America for almost 3500 km and central Australia. On the outskirts of the desert, they are usually bordered by transitional zones of semi-deserts.

The climate in the deserts is sharply continental. Summer is very dry and hot, during the day the air temperature in the shade rises above 40 ° (in tropical deserts up to 58 °). At night, the heat subsides, the temperature often drops to 0 °. In winter, colds come, even in the Sahara at this time there are frosts. There is little precipitation in the deserts - no more than 180 mm in year. Chile's Atacama Desert gets fewer than 10 mm. In places in the tropical deserts, there is no rain for several years in a row.

In a hot, sultry summer, the meager remains of plants in the soils of the desert, as it were, “burn out”. Hence the light gray or light yellow (sometimes almost white) color of the soils, which are called gray soils. Most often, the soil cover in deserts is very weakly expressed. Stony or clayey areas are replaced here by seas of moving sand. "Sand waves" - dunes - reach 12 m height. Their shape is crescent-shaped or crescent-shaped, one slope (concave) is steep, the other is gentle. Connecting at the ends, the dunes often form whole dune chains. Under the influence of the wind, they move at speeds from tens of centimeters to hundreds of meters per year. Unobstructed winds in the desert sometimes reach terrible strength. Then they raise clouds of sand into the air and rush over the desert like a formidable sandstorm.

Clay deserts are almost devoid of vegetation. These are usually low-lying places. They are easily flooded and during the period of light rains they look like lakes, although the depth of such "lakes" is only a few millimeters. The clay layer does not absorb water - it quickly evaporates in the sun, and the dry surface of the earth cracks. Such areas of the desert are called takyrs. Often in deserts, various salts (common salt, Glauber's salt, etc.) come out directly to the surface, forming barren solonchaks. In the sands, plants feel better than on takyrs, because the sands absorb water better and are less saline. In summer, even small reserves of moisture form in the lower, cooler layers of the sands: this is the condensation of water vapor coming from the atmosphere.

The name "desert" does not mean the complete absence of life. Some plants and animals have adapted well to existence in conditions of dry climate and high temperatures.

In the deserts of Central Asia grows saxaul - black and white. Large saxaul sometimes reaches 5 m height. Its leaves-twigs are so small (this helps to retain moisture) that on a hot summer day the trees seem to be bare in winter. But under the black saxaul in the lowlands there is even a weak shadow that saves animals and people from the sun.

In many desert plants, during the hot period, relatively large “spring” leaves are replaced by small “summer” ones. And if larger “summer” leaves are found, then they are either fluffy (near wormwood in Central Asia) or covered with a shiny wax layer. Such leaves reflect the sun's rays and do not overheat. In some plants (sand acacia), the leaves have turned into thorns, which also prevents moisture from evaporating. A small shrub - black wormwood - is usually devoid of leaves and looks very gloomy. And only in spring the black wormwood seems to come to life, covered for a short while with fluffy silvery foliage.

In the deserts of the Western Hemisphere, many different cacti grow. They adapted to the arid climate in their own way: large reserves of water accumulate in the fleshy stems and leaves, sometimes 96% of the total weight of the plant. North American cactus carnegia giant (height up to 15 m) stores in its stems 2-3 thousand. l water. Desert plants tend to have well-developed root systems. It allows them to extract moisture from deep layers of the soil. Some of these plants (desert sedge) can fix sands with a powerful root system.

Desert animals also have their own adaptations to the environment. Many desert dwellers are painted in yellow and gray tones, which allows them to hide from enemies or sneak up on prey unnoticed.

All the inhabitants of the desert try to hide from the scorching heat. Pigeons, sparrows and owls manage to nest and rest in the walls of wells. Birds of prey (eagles, crows, falcons) build nests on mounds and in the ruins of buildings, choosing the shady side. Many animals hide in burrows where it is not so dry and hot in summer and not too cold in winter. And if the inhabitants of most temperate zones hibernate in winter, then other desert animals fall asleep in summer, thus enduring a lack of moisture.

And the thin-toed ground squirrel does without drinking water at all: it has enough moisture contained in the plants it eats. The upland jerboa also does not "know how" to drink: when in captivity they offer water to it, it wets its paws in it and licks them.

Like many inhabitants of the steppes, some desert animals are excellent runners. Huge distances run in search of water and food wild asses kulans. They can reach speeds up to 70 km/h. Cheetahs run even faster - wild cats on long legs with semi-retractable claws.

The dry climate of the deserts is extremely unfavorable for amphibians, but there are a lot of reptiles here: various snakes, lizards (including very large monitor lizards), turtles. Fleeing from the heat and from enemies, many of them quickly burrow into the sand. And the agama lizard, on the contrary, climbs the bushes - away from the hot sand.

The camel is excellently adapted to life in the desert. He can eat grass, which is not digested by other animals, drinks little, is able to drink even salt water. Camels tolerate prolonged hunger well: a supply of fat is deposited in their humps (up to 100 kg and more). On the body and legs of the camel there are calluses that allow him to lie down on hot sand. Leaning on a wide cloven hoof, the camel moves freely on the sands. All these features make it an indispensable assistant to a person in the desert. The camel walks in a harness, under a pack and a saddle, gives warm wool. It was domesticated 4 thousand years ago.

Traces of ancient settlements and irrigation systems are often found under the desert sands. They were destroyed during the wars, and, abandoned by people, once flowering lands became the prey of the desert. But even now, where grazing areas do not change for a long time or where bushes are cut down too much, the sands, which are no longer held together by plant roots, go on the offensive.

The fixation of loose sands by plants is one of the surest ways desert conquest. In addition, sands can be “forged” with special emulsions, the thin film of which is easily penetrated by young shoots of plants.

If you water the desert with enough moisture, its appearance will change. Then it will be possible to grow rice, cotton, melons, corn, wheat, orchards, vineyards here. Desert oases provide 25-30% of the world's cotton harvest and almost 100% of the world's date harvest. On irrigated lands in the deserts of Central Asia, two crops of various agricultural crops can be harvested a year. More about the desert zone.

Savannah

In the equatorial belts of the northern and southern hemispheres there are tropical steppes - savannahs (from the Spanish "saban" - wild plain). In Africa, in the Brazilian Highlands in South America and in the north of Australia, they occupy vast spaces.

The climate of the savannas is tropical. There are very clearly defined two seasons - dry and wet. In this regard, the whole life of nature is subject to a certain rhythm.

In the dry period, the heat reaches 50 °. At this time, the savanna makes a dull impression: yellowed and withered grass, trees devoid of foliage, red-brown, cracked soil, no visible signs of life.

Savannas are vast expanses covered with grassy vegetation with sparsely scattered acacias, baobabs and shrubs.

But then the rains begin, and the savannah awaits literally before our eyes. The soil greedily absorbs moisture and is covered with tall, taller than human growth, grass. Trees and shrubs growing in groups or alone are green everywhere. The crowns of the trees are umbrella-shaped, especially in acacias.

The largest plant in the African savannas is the baobab. It is not taller than our pine, but its trunk is extremely thick - up to 10 m across. Outwardly, this tree is unattractive, only its large white flowers are beautiful. Baobab fruits are not tasty, but for monkeys they are a real delicacy.

Eucalyptus trees grow in the savannahs of Australia - giant trees up to 150 m. There are many types of them. In some species of eucalyptus, the leaves can turn to the sun's rays with an edge and therefore give almost no shade, but this reduces the evaporation of moisture. Among the rarely scattered trees there is a scrub - dense thickets of brigolo acacia, desert oak, sandalwood. Between them come across bizarre "bottle trees" with a trunk swollen from the base to the crown.

The fauna of the savannas, especially African ones, is unusually rich and diverse. Large representatives of land animals live here: clumsy hippos live on the shores of lakes and in the water, heavy buffaloes come, among the branches of mimosa you can see beautiful giraffe heads. In the thick of the grass, crouching to the ground, a lion guards its prey. And not always the fast legs of antelopes save these light graceful animals from the formidable lord African savannah. But more often, careless zebras become its victims.

A slight rustle of grass betrays the presence of other inhabitants. These are snakes. There are a lot of them here, and the most terrible of them is the asp. Both man and animals are afraid of him: the bite of an asp is fatal. Only the buffoon eagle fearlessly fights this snake and almost always wins. See also: .

The abundance of heat, and during the wet period and rainfall, fertile, like our black soil, soils make it possible to grow various crops in the savannah zone, cotton, peanuts, sugar cane, bananas, pineapples. Therefore, people have been farming here since time immemorial, and livestock graze on the luxurious pastures of the savannas. In the African savannas lives the largest modern bird - the African ostrich.

Rainforests

Tropical forests grow near the equator, on both sides of it, between the northern and southern tropics. It's very hot and humid here. The annual rainfall reaches 10,000 tons in some places. mm, and in Cherrapunj (India) - 12 thousand. mm. This is 20 times more than in temperate forests. The abundance of heat and moisture is the main reason for the fabulous richness and diversity of plants and animals in the tropical rainforest.

The weather here is remarkably consistent. Before sunrise, the forest is rather cool and quiet, the sky is cloudless. The sun is rising and the temperature is starting to rise. By noon, the heat sets in, the air becomes suffocating. Two or three hours later, clouds appear in the sky, lightning flashes, deafening peals of thunder shake the air, and a downpour begins. Water flows like a continuous stream. Under its weight, branches of trees break and collapse. Rivers overflow their banks. The rain usually lasts no more than an hour. Before sunset, the sky clears, the wind subsides, and soon the forest plunges into the darkness of the night, which comes quickly, almost without twilight.

Red lateritic soils up to several tens of meters thick form under tropical rainforests. Their color is due to the presence of a large amount of iron oxides. Sometimes yellow-white aluminum oxides are also mixed in - then the soil becomes spotty. During tropical downpours, a significant part of the humus is washed out of the soil, and for the cultivation of cultivated plants (sugarcane, citrus fruits, etc.), it has to be fertilized.

Some trees lose leaves alternately from different branches. Falling leaves usually do not turn yellow, and therefore green color prevails everywhere. In the tropics, there are up to 600 species of various ficuses, some of them are much larger than our oak. In the forest grow tree-like ferns that look like palm trees. There are a lot of palm trees in the tropics. They do not have branches - the leaves are collected at the top of a tall trunk. The fruits of date, coconut, oil and other palms are used by man.

A variety of animals live in the wilds of the rainforest. From gigantic elephants, rhinos, hippos to barely noticeable insects - everyone finds shelter and food here. Representatives of some animal groups in tropical forests are numerous. It is here that most monkeys live, including anthropoids. Of the birds alone

There are more than 150 species of parrots in South America. The Amazon parrot is easy to teach to speak. The parrot does not understand the meaning of the spoken words - it simply imitates the combination of sounds. There are a lot of insects in the rainforest: over 700 species of butterflies are known in Brazil, which is almost five times more than in Europe. Some of them are giants, such as the tizania butterfly: its wingspan is up to 30 cm.

In water-rich tropical forests, along with various reptiles (crocodiles, turtles, lizards, snakes), there are many amphibians. On the island of Kalimantan alone, there are 7 times more amphibian species than in Europe. Tropical reptiles reach enormous sizes: some crocodiles are up to 10 m, and the South American anaconda boa reaches 9 m. There are a lot of different ants in the tropics. The abundance of plant food attracts many herbivorous animals to the tropical forests, which in turn are followed by predators: leopards (panthers), jaguars, tigers, various mustelids, etc. The striped or spotted color of many inhabitants, although it seems very bright and noticeable, in fact, it helps animals hide in the semi-darkness of the lower tiers of the tropical forest, penetrated in some places by the sun's rays.

The nature of the so-called mangrove tropical forests is peculiar. They grow on low-lying sea coasts, protected from the surf, but flooded during high tide hours. Mangrove forests are dense thickets of low (5-10 m) trees and shrubs. They grow on viscous muddy soil. Under such conditions, the plant is supported by branched aerial (stilted) roots, which are immersed in silt. But since the muddy soil here is poisoned with hydrogen sulfide, plants receive oxygen only from the air - with the help of other, special aerial roots. At the same time, fresh water reserves are formed in old leaves, which are necessary for young foliage. The fruits of plants have air cavities and do not sink in water, but can swim in the ocean for a long time until they linger somewhere on the shallows and germinate. Mangrove forests, by fixing silt and sand, interfere with navigation in the mouths of tropical rivers.

The rich nature of tropical forests has long supplied people with their gifts. But even today, large areas of wild jungle are inaccessible, swampy, and poorly developed by man. The rainforest is growing very fast. Abandoned for some reason fields, roads, clearings and clearings immediately overgrow. People all the time have to fight against the jungle advancing on the fields. Raids of predators on villages, monkeys and ungulates on plantations bring a lot of harm.

Many great representatives tropical fauna(elephants, rhinos, antelopes) was barbarously exterminated by the European colonialists. Now some states have already taken measures to protect rare tropical animals: hunting is prohibited, reserves have been created.

The appearance of the natural zones of the Earth and their boundaries were not always the same as they are now. Over the long history of our planet, the relief, climate, vegetation, and fauna have repeatedly changed.

In the distant past, the Earth experienced many cold snaps. During the last such period, a significant part of Eurasia and North America was covered with thick ice.

In the southern hemisphere, ice has penetrated into South America and Australia. But then it became warmer again and the ice receded in the northern hemisphere to the north, and in the southern hemisphere to the south, remaining huge caps only in Greenland and Antarctica.

After the end of the last ice age, modern natural zones arose on Earth. But even now they do not remain unchanged, because nature has not stopped in eternal development, it continues to change and renew itself continuously. A significant role in this process is played by a person, his labor activity. Man grows cultivated plants in the place of wild steppes and dense forests, destroys some animals and breeds others, irrigates arid territories and drains swamps, connects rivers and creates artificial seas - he transforms the face of the Earth.

But sometimes human impact on nature leads to undesirable consequences. The plowing of lands is often accompanied by erosion and washout of soils, their scattering and, consequently, the deterioration of the conditions for the existence of plants. Therefore, in the USA, after 2/3 of the forests were destroyed, the area of ​​deserts doubled.

The burning of forests in Africa has caused deserts to invade the savannah, which in turn arises where tropical forests are reduced.

Such changes in geographic areas reduce natural resources our planet. The transformation of nature must be reasonable. We must not impoverish her, but make her even richer and more beautiful.