What is natural zonality in geography. What is natural zonation? Natural zones of the equatorial and subtropical climatic zone

Remember:

Answer: The natural complex is a relatively homogeneous area earth's surface, whose unity is due to its geographical location, common history development and modern similar natural processes. All components of nature interact within the natural complex: Earth's crust with the structure inherent in it in a given place, the atmosphere with its properties (the climate characteristic of this place), water, the organic world. As a result, each natural complex is a new holistic education, which has certain features that distinguish it from others. Natural complexes within the land are commonly called natural territorial complexes(PTK). On the territory of Africa, large natural complexes - the Sahara, the East African Highlands, the Congo Basin (Equatorial Africa), etc. Formed in the ocean and other water bodies (in a lake, river) - natural aquatic (PAC); natural-anthropogenic landscapes (NAL) are created by human economic activity on a natural basis.

Question: What do the terms " latitudinal zonality"and" altitudinal zonality "?

Answer: Altitudinal zonality is a regular change in natural complexes in the mountains, associated with a change climatic conditions in height. The number of altitudinal belts depends on the height of the mountains and their position relative to the equator. The change in altitudinal belts and the order of their placement are similar to the change in natural zones on the plains, although they have some features associated with the nature of the mountains, as well as the existence of altitudinal belts that have no analogues in the plains.

Question: According to the appearance of what natural component, natural areas are named?

Answer: natural area geographical area) - a land area (part of a geographical zone) with certain conditions of temperature and moisture (the ratio of heat and moisture). It is distinguished by the relative homogeneity of flora and fauna and soils, the regime of precipitation and runoff, and features exogenous processes. The change of natural zones on land obeys the laws of latitudinal (geographical) zonality, as a result of which natural zones on the plains regularly replace each other either in the latitudinal direction (from the poles to the equator) or from the oceans deep into the continents. Most zones are named after the predominant type of vegetation (for example, tundra zone, coniferous forest zone, savanna zone, etc.).

My geographical research:

Question: Which continent has the largest set of natural areas and which has the smallest?

Answer: The Eurasia mainland has the largest set of natural zones.

The mainland Antarctica has the smallest set of natural zones.

Question: Which continents are close to each other in terms of the set of natural zones?

Answer: In terms of the set of natural zones, the continents of Eurasia and North America are close to each other.

Question: On what continents is the location of natural zones close to latitudinal?

Answer: There are not so many areas in which natural zones have an exactly latitudinal strike, and that they occupy very limited areas on the surface of the Earth. In Eurasia, these areas include East End Russian Plain and West Siberian Plain. On the Ural Range separating them, latitudinal zonality is disturbed by vertical zonality. Within North America, areas in which natural areas have strictly latitudinal position, even less than in Eurasia: latitudinal zonality is expressed with sufficient distinctness only between 80 and 95° W. e. In equatorial Africa, areas with zones elongated strictly from west to east are significant, they occupy the western (most) part of the mainland, and do not extend to the east beyond 25 ° E. e. In the southern part of the mainland, the areas of zones elongated in longitude extend almost to the tropic. In South America and Australia, there are no areas with a clearly expressed latitudinal zonality; only the boundaries of zones are found that are close in strike in longitude (in the southern part of Brazil, Paraguay, and Argentina, as well as in the central part of Australia). So, the location of natural zones in the form of strips elongated strictly from west to east is observed in the following conditions: 1) on the plains, 2) in areas of temperate continentality, remote from advection centers, where the conditions of heat and moisture are close to average latitudinal values, and 3) in areas where the amount of average annual precipitation varies from north to south.

Localities that meet such conditions have a limited distribution on the Earth's surface, and therefore the latitudinal zonality in pure form is relatively rare.

Question: On what continents do natural zones extend close to meridional?

Answer: Remoteness from the oceans and features of the general circulation of the atmosphere are the main reasons for the meridional change of natural zones, in Eurasia, where the land reaches its maximum size, the meridional change of natural zones can be traced especially well.

In the temperate zone, western transport brings moisture relatively uniformly to the western coasts. On the eastern coasts - monsoonal circulation (rainy and dry seasons). When moving deep into the forest mainland west coast are replaced by steppes, semi-deserts and deserts. As you approach east coast forests reappear, but of a different type.

Questions and tasks:

Question: What determines the moistening of territories. How does moisture affect natural complexes?

Answer: Humidification of territories depends on the amount of precipitation, the ratio of heat and moisture. The warmer it is, the more moisture evaporates.

Equal amount of precipitation in different belts leads to different consequences: for example 200 ml. precipitation in the cold subarctic zone is excessive (may lead to the formation of swamps), and in the tropical zone it is too insufficient (may lead to the formation of deserts).

Question: Why are the natural zones on the continents not consistently replaced from north to south everywhere?

Answer: The location of natural zones on the continents obeys the law of wide zoning, i.e. they change from north to south with an increase in the number solar radiation. However, there are significant differences, which are explained by the conditions of atmospheric circulation over the mainland, some natural zones replace each other from west to east (along the meridian), because the eastern and western suburbs the mainland is the most humid, and the interior is much drier.

Question: Are there natural complexes in the ocean and why?

Answer: The ocean is divided into natural belts or zones, it is similar to the division according to the principle of latitudinal zonality of natural land zones, only without distinguishing types of climate.

That is, arctic, subarctic, northern and southern temperate, northern and southern subtropical, northern and southern tropical, northern and southern subequatorial, equatorial, subantarctic, antarctic.

In addition, large and smaller natural complexes are distinguished: the largest are oceans, smaller ones are seas, even smaller ones are bays, straits, the smallest are parts of bays, and so on.

In addition, the law of altitudinal zonality also operates in the ocean as on land, which makes it possible to divide the natural complexes of the ocean into complexes of the littoral (coastal waters, shallow waters), pelagials ( surface water in the open sea), bathyals (medium-deep areas of the oceans) and abyssals (the deepest parts of the ocean).

The natural complexes of the Earth are very diverse. These are hot and icy deserts, evergreen forests, endless steppes, bizarre mountains, etc. This diversity is the unique beauty of our planet. You already know how the natural complexes "mainland" and "ocean" were formed. But the nature of each continent, like each ocean, is not the same. In their territories there are various natural zones.

A natural zone is a large natural complex with a common temperature and moisture conditions, soils, vegetation and wildlife. The formation of zones is due to climate, on land - the ratio of heat and moisture. So, if there is a lot of heat and moisture, i.e. high temperatures and a lot of precipitation, a zone of equatorial forests is formed. If the temperatures are high, and there is little precipitation, then a zone of deserts of the tropical belt is formed.

natural areas sushi outwardly differ from each other in the nature of vegetation. The vegetation of the zones of all the components of nature most clearly expresses all key features their nature, the relationship between the components. If there are changes in individual components, then outwardly this affects primarily the change in vegetation. The names of the natural zones of the land were received according to the nature of the vegetation, for example, zones of deserts, equatorial forests, etc.

There are also natural zones (natural belts) in the World Ocean. They differ water masses, organic world and others. The natural zones of the ocean do not have clear external differences, with the exception of the ice cover, and are named after their geographic location as well as climatic zones.

In the placement of natural zones on the earth's surface, scientists have found a clear pattern, which can be clearly seen on the map of natural zones. To understand this regularity, let us trace the change of natural zones on the map from north to south along 20°E. e. In the subarctic zone, where temperatures are low, there is a zone of tundra and forest-tundra, which gives way to taiga to the south. There is enough heat and moisture for the growth of coniferous trees. AT southern half temperate zone the amount of heat and precipitation increases significantly, which contributes to the formation of a zone of mixed and broad-leaved forests. Somewhat to the east, the amount of precipitation decreases, so the steppe zone is located here. On the coast mediterranean sea Europe and Africa have a Mediterranean climate with dry summers. It favors the formation of a zone of hard-leaved evergreen forests and shrubs. Then we get into the tropical zone. Here, in the expanses scorched by the sun, it is hot, the vegetation is sparse and stunted, in some places it is completely absent. This is the zone tropical deserts. To the south, it is replaced by savannas - tropical forest-steppes, where there is already a wet season of the year and a lot of heat. But the amount of rainfall is not enough for the growth of the forest. In the equatorial climatic zone there is a lot of heat and moisture, therefore a zone of humid equatorial forests with very rich vegetation is formed. AT South Africa zones, like climatic zones, are repeated.

In Antarctica, there is a zone of the Antarctic desert, characterized by exceptional severity: very low temperatures and strong winds.

So, you, apparently, were convinced that the alternation of natural zones on the plains is explained by a change in climatic conditions - geographical latitude. However, scientists have long noted that natural conditions change not only when moving from north to south, but also from west to east. To confirm this idea, let us follow the map of the change of zones in Eurasia from west to east along the 45th parallel - in the temperate zone.

On the coast of the Atlantic Ocean, where sea air masses coming from the ocean dominate, there is a zone of broad-leaved forests, beech, oak, linden, etc. grow. When moving east, the forest zone is replaced by a zone of forest-steppes and steppes. The reason is the decrease in rainfall. Even farther to the east, precipitation becomes less and the steppes pass into deserts and semi-deserts, which further to the east are again replaced by steppes, and near Pacific Ocean- zone of mixed forests. These coniferous-deciduous forests amaze with their richness and diversity of plant and animal species.

What explains the alternation of zones at the same latitude? Yes, all the same reasons - a change in the ratio of heat and moisture, which is determined by the proximity or remoteness of the direction of the prevailing winds. There are changes at the same latitudes and in the ocean. They depend on the interaction of the ocean with land, the movement air masses, currents.

The location of natural zones is closely related to climatic zones. Like climatic zones, they naturally replace each other from the equator to the poles due to a decrease in solar heat entering the Earth's surface and uneven moistening. Such a change in natural zones - large natural complexes is called latitudinal zonality. Zoning is manifested in all natural complexes, regardless of their size, as well as in all components. geographical envelope. Zoning is the main geographical pattern.

The change of natural zones, as you know, occurs not only on the plains, but also in the mountains - from the foot to their peaks. Temperature and pressure decrease with altitude, certain height rainfall increases, lighting conditions change. In connection with the change in climatic conditions, there is also a change in natural zones. The zones replacing one another, as it were, encircle mountains at different heights, which is why they are called high-altitude belts. The change of altitudinal belts in the mountains occurs much faster than the change of zones on the plains. It is enough to climb 1 km to be convinced of this.

The first (lower) altitudinal belt of mountains always corresponds to the natural zone in which the mountain is located. So, if the mountain is located in the taiga zone, then when climbing to its top you will find the following altitudinal belts: taiga, mountain tundra, eternal snow. If you have to climb into the Andes near the equator, then you will start your journey from the belt (zone) of equatorial forests. The pattern is as follows: the higher the mountains and the closer they are to the equator, the more altitudinal zones and the more diverse they are. In contrast to zonality on the plains, the alternation of natural zones in the mountains is called altitudinal zonality or altitudinal zonality.

Law geographic zoning manifests itself in the mountainous regions. Some of them we have already considered. Also from geographical latitude change of day and night, seasonal changes depend. If the mountain is near the pole, then there is a polar day and polar night long winters and short cold summers. In the mountains at the equator, day is always equal to night, there are no seasonal changes.

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

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).

Within the belts on land, natural zones are distinguished, 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 the natural zones allocate transition regions. 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- a regular change in natural complexes in height and depth. For mountains, the main reason for this zonality is the change in temperature and amount of moisture with height, and for the depths of the ocean - heat and sunlight.

Change of natural zones depending on the height above sea level in mountainous areas 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 with high mountains and approaching 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 North Arctic Ocean- located in a natural area 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.

Diverse in northern seas types of baleen whales. Blue and bowhead whales, sei whale, fin whale, humpback whale are rare and endangered species and are listed in the Red Book. Inner side long horny plates that replace teeth for whales are 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 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. Moisture coefficient less than one(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.

The composition and structure of plant communities change 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 for long-term movement boundless expanses steppes. Due to the thinness of the snow cover, plant food is also available in winter. Important role bulbs, tubers, rhizomes play in the diet. 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 the 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. In connection with not enough precipitation and frequent droughts in the steppe zone, irrigation systems were built.

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.

In the steppe zone developed various industries industries: metallurgy, mechanical engineering, food, chemical, textile.

Semi-deserts and deserts

Semi-deserts and deserts are located in the southeast of the Russian Plain and in the Caspian lowland.

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.

Animal world semi-deserts and deserts are 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 area stands out for its thickets of reed-reeds (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 spaces coast of the Arctic Ocean from Kola Peninsula to Chukotsky are busy tundra. The southern border of its distribution is practically owls
falls e by the July isotherm of 10 °C. Furthest north southern border the tundra moved away in Siberia - north of 72 ° N. latitude. On the Far East the influence of cold seas led to the fact that the tundra border reaches almost the latitude of St. Petersburg.

Tundra gets 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 northerly 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 arctic islands. Of the vegetation, mosses and lichens predominate, flowering plants are found, compared with 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 cover and survive.

Some devices "serve" plants and in summer time. 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, white 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.

Enough in the tundra low density population. 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, an obstacle to the construction of roads is permafrost.

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 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 Black Sea coast 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. Under 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. Vegetable world It 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, the southern part Central Africa, on the northern coast of the Gulf of Guinea, the northern part of 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 of the subequatorial belt are 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. Primarily 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 of the 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.

The natural complexes of the Earth are very diverse. These are hot and icy deserts, evergreen forests, endless steppes, bizarre mountains, etc. This diversity is the unique beauty of our planet.

You already know how the natural complexes "mainland" and "ocean" were formed. But the nature of each continent, like each ocean, is not the same. In their territories there are various natural zones.

A natural zone is a large natural complex with a common temperature and moisture conditions, soils, vegetation and wildlife. The formation of zones is due to climate, on land - the ratio of heat and moisture. So, if there is a lot of heat and moisture, that is, high temperatures and a lot of precipitation, a zone of equatorial forests is formed. If the temperatures are high, and there is little precipitation, then a zone of deserts of the tropical belt is formed.

Natural areas of land outwardly differ from each other in the nature of vegetation. Of all the components of nature, the vegetation of the zones most clearly expresses all the most important features of their nature, the relationship between the components. If there are changes in individual components, then outwardly this affects primarily the change in vegetation. The names of the natural zones of the land were received according to the nature of the vegetation, for example, zones of deserts, equatorial forests, etc.

Rice. 33. Natural belts of the oceans

There are also natural zones (natural belts) in the World Ocean. They differ in water masses, organic world, etc. The natural zones of the ocean do not have clear external differences, with the exception of the ice cover, and are named according to their geographical location, like climatic zones (Fig. 33).

Patterns of placement of natural zones on Earth. In the placement of natural zones on the earth's surface, scientists have found a clear pattern, which can be clearly seen on the map of natural zones. To understand this regularity, let us trace the change of natural zones on the map from north to south along 20°E. e. In the subarctic zone, where temperatures are low, there is a zone of tundra and forest-tundra, which gives way to taiga to the south. There is enough heat and moisture for the growth of coniferous trees. In the southern half of the temperate zone, the amount of heat and precipitation increases significantly, which contributes to the formation of a zone of mixed and broad-leaved forests. Somewhat to the east, the amount of precipitation decreases, so the steppe zone is located here.

On the Mediterranean coast in Europe and Africa, the Mediterranean climate dominates with dry summers. It favors the formation of a zone of hard-leaved evergreen forests and shrubs. Then we get into the tropical zone. Here, in the expanses scorched by the sun, it is hot, the vegetation is sparse and stunted, in some places it is completely absent. This is a tropical desert zone. To the south, it is replaced by savannas - tropical forest-steppes, where there is already a wet season of the year and a lot of heat. But the amount of rainfall is not enough for the growth of the forest. In the equatorial climatic zone there is a lot of heat and moisture, therefore a zone of humid equatorial forests with very rich vegetation is formed. In South Africa, zones, like climatic zones, are repeated.

Rice. 34. Blooming steppe is especially beautiful in spring

In Antarctica, there is a zone of the Antarctic desert, characterized by exceptional severity: very low temperatures and strong winds.

On the coast of the Atlantic Ocean, where sea air masses coming from the ocean dominate, there is a zone of broad-leaved forests, beech, oak, linden, etc. grow. When moving east, the forest zone is replaced by a zone of forest-steppes and steppes. The reason is the decrease in rainfall. Even farther to the east, precipitation becomes less and the steppes turn into deserts and semi-deserts, which further to the east are again replaced by steppes, and near the Pacific Ocean - by a zone of mixed forests. These coniferous-deciduous forests amaze with their richness and diversity of plant and animal species.

Rice. 35. Due to lack of moisture, plants in the desert do not form a continuous cover.

What explains the alternation of zones at the same latitude? Yes, all the same reasons - a change in the ratio of heat and moisture, which is determined by the proximity or distance from the ocean, the direction of the prevailing winds. There are changes at the same latitudes and in the ocean. They depend on the interaction of the ocean with land, the movement of air masses, currents.

latitudinal zonation. The location of natural zones is closely related to climatic zones. Like climatic zones, they naturally replace each other from the equator to the poles due to a decrease in solar heat entering the Earth's surface and uneven moistening. Such a change in natural zones - large natural complexes is called latitudinal zonality. Zoning is manifested in all natural complexes, regardless of their size, as well as in all components of the geographical envelope. Zoning is the main geographical pattern.

Rice. 36. Coniferous forest

Altitudinal zonation. The change of natural zones, as you know, occurs not only on the plains, but also in the mountains - from the foot to their peaks. With altitude, temperature and pressure decrease, up to a certain height, the amount of precipitation increases, and lighting conditions change. In connection with the change in climatic conditions, there is also a change in natural zones. The zones replacing one another, as it were, encircle mountains at different heights, which is why they are called high-altitude belts. The change of altitudinal belts in the mountains occurs much faster than the change of zones on the plains. It is enough to climb 1 km to be convinced of this.

Rice. 37. Savannah in the dry season

The law of geographical zonality also manifests itself in mountainous regions. Some of them we have already considered. The change of day and night, seasonal changes depend on the geographical latitude. If the mountain is near the pole, then there is a polar day and a polar night, a long winter and a short cold summer. In the mountains at the equator, day is always equal to night, there are no seasonal changes.

How does a natural complex differ from a geographic envelope?
Natural complexes are very diverse. Which of them are called natural areas?
Highlight the main features of the concept of "natural zone".
What are the features of the location of natural zones on the continents and in the ocean?
What is latitudinal zonality and altitudinal zonality?
Which mountains have the largest number of altitudinal belts, which have the least? Why?

Main questions: What determines the distribution of natural zones across the territory? What are the main features of the climate of the arctic, subarctic, temperate, subtropical zones?

General patterns of natural zonality. In the composition of all geographical zones of the mainland, not one, but several natural zones stand out. In the north, the latitudinal zonality of natural zones is clearly manifested, which is due to the evenness of the relief and a uniform increase in the incoming heat. In the central part of the mainland, the change in climatic conditions in the belts occurs in two directions - from north to south and from the oceanic margins to the interior of the mainland. Therefore, natural zones have a location close to meridional.

Natural zone of the arctic deserts formed on the islands of the Arctic Ocean. Cold and high precipitation contribute to the development of glaciation. In summer, in depressions and cracks appear mosses, lichens, cold-resistant herbs and shrubs. arctic soils contain almost no nutrients. With harsh conditions related to the poverty of the animal world. The life of its representatives is connected with the sea. On the islands are formed bird markets. They live in the waters of the seas seals, walruses, bowhead whales. Entering coastal areas from the mainland polar bears, wolves, polar foxes. In Greenland and the Canadian Arctic Archipelago lives muskox, or musk ox.

Natural zone of tundra and forest-tundra occupies the north of the mainland. The short summer quickly gives way to a snowy cold winter. Permafrost is widespread. Tundra in the north moss and lichen. Rare herbs appear in summer ( sedge, cotton grass) and polar flowers - forget-me-nots, polar poppies, dandelions. South of the tundra becomes shrubby: meet dwarf birch and willow, wild rosemary, blueberry, bilberry. Under the conditions of summer waterlogging during thawing, permafrost is formed tundra-gley soil. herds reindeer are the object of hunting of the Eskimos and Indians. Meet polar hare, lemmings. Small animals are prey polar bear, polar wolf, arctic fox. common white partridge, predatory snowy owl, in the summer waterfowl arrive - geese, ducks, waders. Trees appear in the south along the river valleys: black and white spruce.

Taiga natural zone extends south of the forest-tundra. The vegetation is represented by dark coniferous forests from black and white firs and balsam fir. Grow in dry places pines: white(Weymouth), Banks(stone) and red (fig. 39.1). In the taiga zone are typical podzolic and gray forest soils, in the lowlands - peat-marsh.

The coniferous forests of the mountainous Pacific coast are called "rain forests", they grow in conditions a large number precipitation (Fig. 40.1). stands out in the forest stand Douglas fir (Fig. 41.1)- one of the world's giants, the diameter of its trunk reaches 1.5 -2 m, and the height is 100 m. Typical North American coniferous species: thuja, Sitka spruce, yellow pine. Mountains form under the forests brown forest soil.

The animal world is diverse (Fig. 42.1-45.1): many large ungulates: wapiti deer, American Moose, meet in the mountains bighorn goat and bighorn ram. typical brown and black american bear, puma(or cougar) gray and red squirrel, chipmunk, predators - marten, wolf, Canadian lynx, ermine, wolverine, fox, in the rivers - beavers, otters a and musky rat a (muskrat). Variety of forest birds crossbills, warblers etc. In rain forests are common hummingbird.

mixed forests occupy the vicinity of the Great Lakes and part of the Appalachians. It is warmer here in winter, deciduous trees appear among the conifers. : elm, beech, linden, oak, birch, maples: sugar, red(fig. 46.1) , silver. Leaf litter allows the formation sod-podzolic soils. The Appalachian coastline is dominated by broad-leaved forests with exceptional species richness. Diverse oaks, chestnuts, beeches, grow tree hickory, deciduous magnolia, yellow poplar, black walnut, tulip tree

Falling leaves give a lot organic matter and contributes to the formation of fertile brown forest x soils used for arable land. Previously, the animal world of forests was distinguished by unique richness. Its representatives are Virginian deer, gray fox, lynx, baribal black bear, tree porcupine, American mink, weasel, badger, raccoon (Fig. 50.1). endemic flying squirrels, skunks, the only ones in North America marsupials - opossums (Fig. 51.1).

1. What is natural zoning? What is its cause? Why can natural zones change in different directions? What factors determine the patterns of change in natural zones in North America? 3. List the geographical zones in which the territory of North America is located.