Natural zones and their main features. Natural areas Natural areas of the earth briefly

1. List the main natural zones of the Earth.

Tundra, taiga, broad-leaved forest, grassy plain (savannah), deserts and semi-deserts, steppes and forest-steppes, tropical rainforest.

2. What determines the distribution of natural zones on Earth?

natural areas formed due to the distribution of heat and moisture on the planet. The relief, the distance from the ocean affect the location of the zones and their width.

3. Give a brief description of the tundra.

This natural zone is located in the polar zone (most of it is in the permafrost zone), where the air temperature is quite low.

The flora is represented mainly by low-growing plants with a poorly developed root system: mosses, lichens, shrubs, dwarf trees. Ungulates, small predators, and many migratory birds live in the tundra.

4. What trees form the basis of the taiga, mixed and deciduous forests?

• The basis of the taiga is coniferous trees (pine, spruce, fir, larch, etc.);
• Mixed forests are characterized by a mixture of coniferous and broadleaf tree species;
• Wide deciduous forests consist of deciduous trees (oak, hazel, beech, linden, maple, chestnut, hornbeam, elm, ash, etc.).

5. What do all the grassy plains of our planet have in common?

Answer: It is characterized by low rainfall and constantly high air temperature. The savannas are characterized by the presence of a dry period, during which the grasses dry up, and animals tend to water bodies. The vegetation here is predominantly herbaceous, trees are rare. The savannas are characterized by an abundance of large herbivores and predators.

6. Give a brief description of the desert.

Deserts are distinguished by very low humidity; the flora and fauna of the deserts adapt to these difficult conditions. Animals have the property for a long time do without water, wait out the driest months in hibernation, many are nocturnal. Many plants are able to store moisture, most have reduced evaporation, in addition, they have a branched root system that allows you to collect crumbs of moisture from a large volume. On the whole, the flora and fauna are very limited. Of the plants, mainly leafless thorny shrubs are common, of the animals - reptiles (snakes, lizards) and small rodents.

7. Why are there few trees in the steppes, savannahs and deserts?

In the savannahs, steppes and deserts, there is very little rainfall, the trees simply do not have enough water.

9. Using examples, prove that the distribution of natural zones on Earth depends on the distribution of heat and moisture.

Natural zones are formed as a result of the distribution of heat and moisture on the planet: high temperature and low humidity are typical for equatorial deserts, high temperature and high humidity - for equatorial and tropical forests.
Natural zones are stretched from west to east, there are no clear boundaries between them.

For example, savannahs are located where moisture is no longer enough for the growth of humid forests, in the depths of the mainland, and also far from the equator, where for most of the year it is already dominated not by equatorial, but by tropical air mass and the rainy season lasts less than 6 months.

10. Characteristic features of what natural zones are listed?

1. Most big variety species - Humid tropical forest.
2. predominance herbaceous plants- Savannah.
3. Abundance of mosses, lichens and dwarf trees - Tundra.
4. Many coniferous plants of a few species -.

11. Analyze the drawings on p. 116-117 textbook. Is there a connection between the color of animals and their habitat (natural zone)? What is it connected with?

Answer: Yes, there is a connection. This is called protective coloring. Animals thus merge with environment with different purposes. If it is a predator - then for the attack. For example, the striped tiger successfully hides in yellow grass preparing to attack. Polar bear and arctic fox are almost invisible against the background of snow.

To protect themselves from predators, animals have also developed coloration to hide. Examples: jerboa, roe deer, green frog and more. others

12. In what natural areas do these organisms live?

• Dwarf birch - tundra.
• The sloth is a tropical rainforest.
• Kedrovka - taiga.
• Zebra - savannah.
• Oak is a broad-leaved forest.
• Jeyran is a desert.
• White owl - tundra.

13. Using the map on p. 118-119 of the textbook, name the natural zones found on the territory of our country. Which of them occupy the largest area?

The territory of Russia has a large extent from north to south, the relief is mostly flat. Thus, the following natural zones are consistently represented on the vast plains: arctic deserts, tundra, forest-tundra, forests, forest-steppes, steppes, semi-deserts, deserts, subtropics. AT mountains - high-rise explanation. A large area is occupied by taiga, steppe, mixed forest and tundra.

A natural zone is a part of the earth's surface with the same type of relief, soil, flora and fauna. The main forming factor of the natural zone is the climate. On the territory of Russia, 8 natural complexes have been formed. They follow each other from north to south. the largest territory occupies the taiga zone, and the smallest - the region of semi-deserts and deserts. Below is a distribution map and a geographical description of all natural zones in Russia, as well as a table with brief description each natural area.

Read also:

Map of natural areas of Russia

arctic desert

The upper border of the region passes through the Franz Josef Land archipelago, the lower border - on Wrangel Island. Main Feature is the presence of ice and snow throughout the year. average temperature in winter it is about -50º C. During this period, a lot of snow falls, strong winds blow. The polar night lasts 4 months. Summer temperatures average +4º C. August is considered the warmest month of the year.

There are no lakes or swamps. The flora is represented mainly by lichens. Here you can count several endemics: arctic willow, cotton grass, forget-me-not and chickweed. few because of poor flora. Polar bears, arctic foxes, reindeer and lemmings thrive in the cold desert. Rocky coasts were chosen by eiders, guillemots and other birds. The shores of some islands are solid bird colonies.

Tundra

The natural complex stretched from the Kola Peninsula to Chukotka. Its area is one eighth of the entire area of ​​Russia. It is characterized by plains, only mountains and hills appear near the Urals. This region is characterized harsh winter with average temperatures around -32º C and a duration of more than half a year. During the winter season, strong winds blow, which remove the layer of snow from the soil. Because of this, the soil freezes, and during the thaw it becomes swampy. The polar night lasts from December to February.

From the middle of summer the sun does not set. It does not rise high above the horizon, therefore, most of the rays are scattered in the atmosphere. The so-called polar day is coming. Summer average temperatures in the tundra do not exceed +5º C. Among the vegetation, lichens of all kinds and mosses are especially widespread. Perennial crops are represented by saxifrage, lingonberries, wild rosemary, cassandra and cloudberries. are the food base for reindeer and hares. In addition to them, wolves, arctic foxes and partridges. During the short summer, loons, waders and geese can be observed.

forest tundra

The region stretches from the tundra to the taiga. The climate in this transitional zone is much milder than in the neighboring northern one. In January, the thermometer does not rise above -40º C, cold winds are constantly blowing. However, the snow cover is permanent. Winter lasts up to eight months. The average summer temperature is 15º C. Due to high humidity and relatively low summer temperatures, the soil is heavily waterlogged.

The forest tundra is characterized by forests consisting of deciduous trees, birches and spruces. Another feature of the flora are meadows. Medicinal herbs bloom on them in late spring. The swampy area is rich in peat and mosses. Moss grows in this natural area, which is a source of food for deer. The world of mammals is more diverse than in the tundra. You can observe wolverines, bears, wolves and arctic foxes. Swamps, lakes and rivers are inhabited waterfowl: ducks, swans and loons. Unique birds are found in the forest-tundra: peregrine falcons, Siberian Cranes and gooses. Some birds, such as snowy owl and partridge, live in this natural area all year round without flying anywhere.

Taiga

Stretched from the western borders to the coast Pacific Ocean. The area of ​​the biome is about 15 million km². Most of the territory is occupied by forests. Basically, the area is almost untouched by man. The taiga winter is cold, the average temperature is -29 ° C. The snow cover does not melt for more than three months. Summer figures average +18º C. Precipitation is presented in the form of heavy rains, due to which the level of humidity increases.

The natural zone is represented by numerous rivers, lakes and other bodies of water. The soil layer consists of humus and a large amount of minerals. and unique. Coniferous and deciduous forests are widely represented in the taiga zone. In addition to them, there are wetlands and meadows. Due to the stable climate and lack of extreme temperatures most animals do not change their habitat all year round. Hazel grouse, nutcracker, capercaillie do not fly away, but constantly nest in the taiga.

The climate was harsh. A few frogs and lizards fall into suspended animation with the onset of persistent frosts. The world is represented by wolverine, lynx, elk, brown bear, sable. The taiga is saturated with blood-sucking insects that swarm in huge numbers. Often the midge is a carrier of infectious diseases.

The territory extends from the East European Plain to the Far East. The biome is characterized by a mild climate. The winter temperature does not exceed -25°C. Numerous anticyclones form over the Far East during this period. Snow evenly covers the entire territory of the natural complex. Summers are mostly mild and humid. July air warms up to +20º C. The warm period lasts 4 months. At this time, the maximum amount of rain falls.

The territory of mixed and broad-leaved forests is known for its water potential. There are long flood rivers and lakes. Bogs are practically absent. The earth is saturated with nitrogen, magnesium, calcium and aluminum. Korean cedar, Manchurian walnut, Amur linden, larch grow in the forests. Lots of shrubs. Mosses and lichens cover the soil only in dark and damp places. Forests are rich in fruit, berry plants and mushrooms. This creates conditions for comfortable living of many species of animals. These forests are the most used by man in his activities. The lands untouched by man are distinguished by the greatest species diversity.

Of the inhabitants, one can distinguish a viper, a viviparous lizard, a snake. Various birds are found in the forests: hazel grouse, black grouse, crossbill, owl, owl. The natural area is rich in predators - wolves, ermines, foxes, martens are its permanent inhabitants. AT recent times deer population has been significantly reduced. The forests remain home to hedgehogs, badgers, nutrias, moles, hares and marsh turtles.

forest-steppe zone

The territory that united the East European Plain, the West Siberian Plain and Southern Urals, and is transitional between forests and steppes. Winter in the western part of the natural zone is very mild and snowy. Temperatures in the east drop to -20°C with little snow. Summer temperatures average +18º C, with little rain.

It is characterized by a combination of forests and grass cover. Maple, oak, linden grow in the European part. Aspens and birches predominate in the Asian zone. The steppe regions are rich in bluegrass and clover. Almost the entire steppe is used in agriculture. People cultivate corn, rye, wheat. Animals such as squirrel, marten, ground squirrel, bustard, elk live here.

The anthropogenic factor has led the forest-steppe zone to desertification, the land and water bodies are polluted with toxic substances and nitrates. Unstable vegetable world cannot recover from human activities. The natural complex of the forest-steppe is gradually disappearing on the territory of Russia.

steppe zone

The natural zone is located on the East European Plain and in Western Siberia. In winter, it is colder in the eastern part of the zone than in the west. In summer, the average temperature readings are + 20 ° C. The maximum amount of precipitation occurs in June. There is an alternation of wet and dry seasons. The soil is chernozem, well suited for growing cereals. Erosion is taking place in some areas.

Herbaceous vegetation predominates in the steppe: clover, bluegrass, wild oats. Sometimes shrubs are found on the ground: broom, spirea, dereza and blackthorn. All plants are an excellent food base for animals. In the steppes, there are a large number of voles, marmots and pikas. The world is represented by ferrets, foxes and wolves. In this natural complex there is an area of ​​predatory birds: owls, hawks, harriers and buzzards.

Semi-deserts and deserts

The territory stretched from the Caspian lowland to the borders with Kazakhstan. The thermometer in winter drops to -16º C, blowing gusty winds. There is practically no snow, so the soil freezes deeply. The maximum amount of precipitation falls on a short spring period. The average temperature in summer is +25° C. The lands are saline, there are many sands and solonchaks.

The plant world is not diverse. Only here you can see remaria, malcomia, acacia, camel thorn, cacti and some cereals. During a drought, some plants wither, retaining underground organs. The most recognizable desert tree is the saxaul. There are practically no leaves on it, which significantly reduces the evaporation of moisture. Of the herbaceous plants, black wormwood is well-known, which covers the earth, protecting it from drought.

Desert dwellers lead. Ground squirrels, jerboas and gerbils can hibernate with the onset of heat. The world of amphibians is represented by geckos, boas and monitor lizards. Of the predators, corsairs, wolves and foxes can be noted. Saiga and camel are large. Of the birds, there is a lark, a saja and a gyrfalcon.

Table of natural zones of Russia

Natural zones of the Earth

A comprehensive scientific study of nature allowed V. V. Dokuchaev in 1898 to formulate the law of geographical zonality, according to which climate, water, soil, relief, flora and fauna in a certain area are closely interconnected and should be studied as a whole. He proposed dividing the Earth's surface into zones that naturally repeat themselves in the Northern and Southern hemispheres.

Different geographical (natural) zones Earth characterized by a certain combination of heat and moisture, soils, flora and fauna and, as a result, - features economic activity their population. These are zones of forests, steppes, deserts, tundra, savannas, as well as transitional zones of forest-tundra, semi-deserts, forest-tundra. The names of natural areas are traditionally given according to the prevailing type of vegetation, which reflects the most important features of the landscape.

The regular change of vegetation is an indicator of a general increase in heat. In the tundra, the average temperature of the warm month in the year - July - does not exceed + 10 ° С, in the taiga it fluctuates between + 10 ... + 18 ° С in the strip of deciduous and mixed forests+ 18 ... + 20 ° С, in the steppe and forest-steppe + 22 ... + 24 ° С, in semi-deserts and deserts - above +30 ° С.

Most animal organisms remain active at temperatures from 0 to +30°C. However, temperatures from + 10 ° C and above are considered the best for growth and development. It is obvious that such a thermal regime is typical for the equatorial, subequatorial, tropical, subtropical, as well as moderate climatic zones Earth. The intensity of vegetation development in natural areas also depends on the amount of precipitation. Compare, for example, their number in the zone of forests and deserts (see map of the atlas).

So, natural areas- These are natural complexes that occupy large areas and are characterized by the dominance of one zonal type of landscape. They are formed mainly under the influence of climate - the features of the distribution of heat and moisture, their ratio. Each natural zone has its own type of soil, vegetation and wildlife.

The appearance of the natural zone is determined by the type of vegetation cover. But the nature of vegetation depends on climatic conditions - thermal conditions, moisture, illumination, soils, etc.

As a rule, natural zones are elongated in the form of wide strips from west to east. There are no clear boundaries between them, they gradually pass into one another. The latitudinal location of natural zones is disturbed by the uneven distribution of land and ocean, relief, distance from the ocean.

General characteristics of the main natural zones of the Earth

Let us characterize the main natural zones of the Earth, starting from the equator and moving towards the poles.

Forests are located on all continents of the Earth, except for Antarctica. Forest zones have both common features and special features that are characteristic only of the taiga, mixed and broad-leaved forests or tropical forests.

The common features of the forest zone include: warm or hot summers, a fairly large amount of precipitation (from 600 to 1000 or more mm per year), large full-flowing rivers, and the predominance of woody vegetation. The equatorial forests, which occupy 6% of the land, receive the greatest amount of heat and moisture. They rightfully hold the first place among the forest zones of the Earth in terms of the diversity of plants and animals. 4/5 of all plant species grow here and 1/2 of all land animal species live.

The climate of the equatorial forests is hot and humid. Medium annual temperatures+24... +28°С. The annual amount of precipitation is more than 1000 mm. It is in the equatorial forest that you can find the largest number of ancient animal species, such as amphibians: frogs, newts, salamanders, toads or marsupials: opossums in America, possums in Australia, tenrecs in Africa, lemurs in Madagascar, loris in Asia; ancient animals are also such inhabitants of the equatorial forests as armadillos, anteaters, pangolins.

AT equatorial forests the richest vegetation is located in several tiers. Many species of birds live in the crowns of trees: hummingbirds, hornbills, birds of paradise, crowned pigeons, numerous species of parrots: cockatoo, macaw, Amazon, Jaco. These birds have tenacious paws and strong beaks: they not only fly, but also climb trees beautifully. Animals living in the crowns of trees also have tenacious paws and tail: sloths, monkeys, howler monkeys, flying foxes, tree kangaroos. The largest animal that lives in the crowns of trees is the gorilla. In such forests, many beautiful butterflies and other insects live: termites, ants, etc. Various types of snakes. Anaconda - the largest snake in the world, reaches a length of 10 m or more. The high-water rivers of the equatorial forests are rich in fish.

The equatorial forests occupy the largest areas in South America, in the Amazon River basin, and in Africa - in the Congo River basin. The Amazon is the deepest river in the world. Every second it carries 220 thousand m3 of water into the Atlantic Ocean. The Congo is the second largest river in the world. Equatorial forests are also common on the islands of the Malaysian archipelago and Oceania, in the southeastern regions of Asia, in northeastern Australia (see the map in the atlas).

Valuable tree species: mahogany, black, yellow - the wealth of equatorial forests. The harvesting of valuable wood species threatens the preservation of the Earth's unique forests. Space images have shown that in a number of areas of the Amazon, forest destruction is proceeding at a catastrophic pace, many times faster than their restoration. At the same time, many species of unique plants and animals are disappearing.

Variable wet monsoon forests

Variably humid monsoon forests can also be found on all continents of the Earth, except for Antarctica. If it is summer all the time in the equatorial forests, then three seasons are pronounced here: dry cool (November-February) - winter monsoon; dry hot (March-May) - transitional season; humid hot (June-October) - summer monsoon. The hottest month is May, when the sun is almost at its zenith, the rivers dry up, the trees shed their leaves, the grass turns yellow.

Summer monsoon comes at the end of May hurricane winds, thunderstorms, heavy rains. Nature comes to life. Due to the alternation of dry and wet seasons, monsoon forests are called variable wet.

The monsoon forests of India are located in the tropical climate zone. grow here valuable breeds trees, distinguished by the strength and durability of wood: teak, sal, sandalwood, satin and ironwood. Teak wood is not afraid of fire and water, it is widely used for building ships. Sal also has a durable and strong wood. Sandalwood and satin wood are used in the manufacture of varnishes and paints.

Animal world The Indian jungle is rich and varied: elephants, bulls, rhinos, monkeys. Lots of birds and reptiles.

Monsoon forests of tropical and subtropical regions are also characteristic of Southeast Asia, Central and South America, northern and northeastern regions of Australia (see the map in the atlas).

Temperate monsoon forests

Temperate monsoon forests are found only in Eurasia. Ussuri taiga is a special place on Far East. This is a real thicket: the forests are multi-tiered, dense, intertwined with lianas and wild grapes. Cedar, walnut, linden, ash and oak grow here. Rough vegetation is the result of an abundance of seasonal rainfall and a rather mild climate. Here you can meet the Ussuri tiger - the largest representative of its species.
The rivers of the monsoon forests are fed by rain and flood during the summer. monsoon rains. The largest of them are the Ganges, Indus, Amur.

The monsoon forests are heavily cut down. According to experts, in Eurasia only 5% of the former forests remained. Monsoon forests suffered not so much from forestry, but also from agriculture. It is known that the largest agricultural civilizations appeared on fertile soils in the valleys of the Ganges, Irrawaddy, Indus and their tributaries. The development of agriculture required new territories - forests were cut down. Farming has adapted over the centuries to alternating wet and dry seasons. The main agricultural season is the wet monsoon period. The most important crops - rice, jute, sugarcane - are dated for it. In the dry cool season, barley, legumes, and potatoes are planted. In the dry hot season, agriculture is possible only with artificial irrigation. The monsoon is capricious, its delay leads to severe droughts and the death of crops. Therefore, artificial irrigation is necessary.

temperate forests

Temperate forests occupy significant areas in Eurasia and North America(see the map in the atlas).

AT northern regions- this is the taiga, to the south - mixed and broadleaf forests . In the forest zone of the temperate zone, the seasons of the year are pronounced. Average temperatures in January are negative everywhere, in some places up to -40°С, in July + 10 ... + 20°С; the amount of precipitation is 300-1000 mm per year. Vegetation of plants in winter stops, for several months there is a snow cover.

Spruce, fir, pine, larch grow both in the taiga of North America and in the taiga of Eurasia. The animal world also has a lot in common. The bear is the master of the taiga. True, in the Siberian taiga it is called - Brown bear, and in the taiga of Canada - grizzlies. You can meet red lynx, elk, wolf, as well as marten, ermine, wolverine, sable. Through the taiga zone flow major rivers Siberia - the Ob, Irtysh, Yenisei, Lena, which are second only to the rivers of the equatorial forest zone in terms of runoff.

To the south, the climate becomes milder: mixed and broad-leaved forests grow here, consisting of such species as birch, oak, maple, linden, among which there are also conifers. Typical for the forests of North America are: white oak, sugar maple, yellow birch. Noble deer, elk, wild boar, hare; from predators - a wolf and a fox - representatives of animal world of this zone known to us.

If the northern taiga is classified by scientists-geographers as a zone slightly modified by man, then mixed and broad-leaved forests have been cut down almost everywhere. Their place was taken by agricultural areas, such as the "corn belt" in the United States, in this zone many cities and highways are concentrated. In Europe and North America, the natural landscapes of these forests have been preserved only in mountainous regions.

Savannah

Savannah is a natural zone of low latitudes in the subequatorial, tropical and subtropical zones of the Northern and Southern Hemispheres. It occupies about 40% of the territory of Africa (south of the Sahara), distributed in South and Central America, Southeast Asia, Australia (see the map in the atlas). The savanna is dominated by herbaceous vegetation with isolated trees or groups of trees (acacia, eucalyptus, baobab) and shrubs.

The fauna of the African savannas is surprisingly diverse. To adapt to the conditions of endless dry spaces, nature endowed animals with unique properties. For example, the giraffe is considered the tallest animal on Earth. Its height exceeds 5 m, it has a long tongue (about 50 cm). All this is necessary for a giraffe in order to reach the high branches of acacias. Crowns of acacias begin at a height of 5 m, and giraffes have practically no competitors, calmly eating tree branches. Typical animals of the savannas are zebras, elephants, ostriches.

steppes

Steppes are found on all continents of the Earth, except for Antarctica (in the temperate and subtropical zones of the Northern and Southern Hemispheres). They are distinguished by an abundance of solar heat, low rainfall (up to 400 mm per year), as well as warm or hot summers. The main vegetation of the steppes is grasses. The steppes are called differently. In South America, the tropical steppes are called pampas, which in the language of the Indians means "a large expanse without a forest." Animals characteristic of the pampa are the llama, the armadillo, the viscacha, a rodent that looks like a rabbit.

In North America, the steppes are called prairies. They are located in both temperate and subtropical climatic zones. The "kings" of the American prairies have long been bison. By the end of the 19th century, they were almost completely exterminated. Currently, through the efforts of the state and the public, the number of bison is being restored. Another inhabitant of the prairies is the coyote - the steppe wolf. On the banks of the rivers in the bushes you can meet a large spotted cat - a jaguar. The peccary is a small boar-like animal also typical of the prairies.

The steppes of Eurasia are located in the temperate zone. They are very different from the American prairies and African savannas. It has a drier, sharply continental climate. It is very cold in winter (average temperature - 20°C), and very hot in summer (average temperature + 25°C), strong winds. In summer, the vegetation of the steppes is sparse, but in spring the steppe is transformed: it blooms with many varieties of lilies and poppies, tulips.

The flowering time does not last long, about 10 days. Then a drought sets in, the steppe dries up, the colors fade, and by autumn everything takes on a yellow-gray color.

The most fertile soils of the Earth are located in the steppes, so they are almost completely plowed up. The treeless expanses of the steppes of the temperate zone are distinguished by strong winds. Here, wind erosion of soils occurs very intensively - frequent dust storms. To preserve soil fertility, forest belts are planted, organic fertilizers and light agricultural machinery are used.

desert

Deserts occupy vast spaces - up to 10% of the Earth's land mass. They are located on all continents and in different climatic zones: temperate, subtropical, tropical and even polar.

There are common features in the climate of the deserts of the tropical and temperate zones. Firstly, the abundance of solar heat, secondly, the large amplitude of temperatures in winter and summer, day and night, and thirdly, a small amount of precipitation (up to 150 mm per year). However, the latter feature is also characteristic of the polar deserts.

In the deserts of the tropical zone, the average summer temperature is +30°C, winter + 10°C. The greatest tropical deserts of the Earth are located in Africa: Sahara, Kalahari, Namib.

Desert plants and animals adapt to dry and hot climates. So, for example, a giant cactus can store up to 3000 liters of water and “not drink” for up to two years; and the velvichia plant, found in Namib desert capable of absorbing water from the air. A camel is an indispensable helper of a person in the desert. He can be without food and water for a long time, storing them in his humps.

The largest desert in Asia, Rub al-Khali, located on the Arabian Peninsula, is also located in the tropical zone. The desert regions of North and South America and Australia are located in tropical and subtropical climatic zones.

The deserts of the temperate zone of Eurasia are also characterized by a low amount of precipitation and a large amplitude of temperatures, both annual and daily. However, they are characterized by lower winter temperatures and a pronounced flowering period in spring. Such deserts are located in Central Asia east of the Caspian Sea. The fauna here is represented by various species of snakes, rodents, scorpions, turtles, lizards. A typical plant is saxaul.

polar deserts

Polar deserts are located in the polar regions of the Earth. An absolute minimum temperature of 89.2°C has been recorded in Antarctica.

Average winter temperatures are -30°С, summer - 0°С. Just like in the deserts of the tropical and temperate zones, little precipitation falls in the polar desert, mainly in the form of snow. The polar night here lasts almost half a year, the polar day lasts almost half a year. Antarctica is considered the highest continent on Earth, given the thickness of its ice shell of 4 km.

Indigenous inhabitants of the polar deserts of Antarctica - emperor penguins. They cannot fly, but they are excellent swimmers. They can dive to great depths and swim great distances, escaping from their enemies - seals.

The northern polar region of the Earth - the Arctic - got its name from the ancient Greek arcticos - northern. The southern, as it were, opposite polar region is Antarctica (anti - against). The Arctic occupies the island of Greenland, the islands of the Canadian Arctic Archipelago, as well as the islands and waters of the Arctic Ocean. This area is covered with snow and ice throughout the year. The owner of these places is considered to be a polar bear.

Tundra

Tundra is a treeless natural area with vegetation of mosses, lichens and creeping shrubs. The tundra is distributed in the subarctic climatic zone only in North America and Eurasia, which are characterized by harsh climatic conditions (little solar heat, low temperatures, short cold summer, low rainfall).

Moss lichen was called "reindeer moss" because it is the main food for reindeer. Arctic foxes also live in the tundra, lemmings are small rodents. Among the sparse vegetation there are berry bushes: blueberries, lingonberries, blueberries, as well as dwarf trees: birch, willow.

Permafrost in the soil is a phenomenon characteristic of the tundra, as well as the Siberian taiga. It is worth starting to dig a hole, as at a depth of about 1 m there will be a frozen layer of earth several tens of meters thick. This phenomenon must be taken into account in the construction, industrial and agricultural development of the territory.

In the tundra, everything grows very slowly. It is with this that the need for careful attention to its nature is connected. For example, pastures damaged by deer are restored only after 15-20 years.

Altitudinal zonality

Unlike flat territories, climatic zones and natural zones in the mountains change according to the law of vertical zonality, i.e., from bottom to top. This is because the air temperature decreases with altitude. Consider, as an example, the greatest mountain system world - the Himalayas. Almost all natural zones of the Earth are represented here: a tropical forest grows at the foot, at an altitude of 1500 m it is replaced by broad-leaved forests, which in turn turn into mixed ones at an altitude of 2000 m. fir and juniper. In winter, there is snow for a long time and frosts persist.

Above 3500 m, shrubs and alpine meadows begin, they are called "alpine". In summer, the meadows are covered with a carpet of brightly flowering herbs - poppies, primroses, gentians. Gradually the grasses become lower. Approximately from a height of 4500 m, eternal snow and ice lie. Climatic conditions are very severe here. They live in the mountains rare species animals: mountain goat, chamois, argali, snow leopard.

Latitudinal zonality in the ocean

The world ocean occupies more than 2/3 of the planet's surface. Physical Properties and chemical composition ocean waters are relatively constant and create an environment conducive to life. It is especially important for the life of plants and animals that oxygen and carbon dioxide coming from the air dissolve in water. Photosynthesis of algae occurs mainly in the upper layer of water (up to 100 m).

Marine organisms live mainly in the surface layer of water illuminated by the Sun. These are the smallest plant and animal organisms - plankton (bacteria, algae, smallest animals), a variety of fish and marine mammals(dolphins, whales, seals, etc.), squids, sea ​​snakes and turtles.

There is life on the sea floor too. These are bottom algae, corals, crustaceans, molluscs. They are called benthos (from the Greek benthos - deep). The biomass of the World Ocean is 1000 times smaller than the biomass of the land of the Earth.

The distribution of life in oceans uneven and depends on the amount of solar energy received on its surface. Polar waters are poor in plankton due to low temperatures and long polar nights. The greatest amount of plankton develops in the waters of the temperate zone in summer. The abundance of plankton attracts fish here. The temperate zones of the Earth are the most fishy areas of the oceans. In the tropical zone, the amount of plankton again decreases due to the high salinity of the water and high temperatures.

Formation of natural areas

From today's topic, we have learned how diverse the natural complexes of our planet are. The natural zones of the Earth are full of evergreen forests, endless steppes, various mountain ranges, hot and icy deserts.

Each corner of our planet is distinguished by its uniqueness, diverse climate, relief, flora and fauna, and therefore various natural zones are formed on the territories of each continent.

Let's try to figure out what natural zones are, how they formed, and what was the impetus for their formation.

Natural zones include such complexes that have similar soils, vegetation, wildlife and the similarity of the temperature regime. Natural zones got their names according to the type of vegetation, and they bear such names as the zone of taiga or broad-leaved forests, etc.

Natural areas are diverse, due to the uneven redistribution of solar energy on the Earth's surface. This is the main reason for the heterogeneity of the geographic envelope.

After all, if we consider one of the climatic zones, we can see that those parts of the belt that are closer to the ocean are more humid than its continental parts. And this reason lies not so much in the amount of precipitation, but rather in the ratio of heat and moisture. Because of this, on some continents we are seeing more humid climate, and on the other - arid.

And with the help of the redistribution of solar heat, we see how the same amount of moisture in some climatic zones leads to excess moisture, and in others - to their lack.

So, for example, in a hot tropical zone, a lack of moisture can cause drought and the formation desert territories, whereas, as in the subtropics, excess moisture contributes to the formation of swamps.

So you learned that due to the difference in the amount of solar heat and moisture, various natural zones were formed.

Patterns of placement of natural zones

The natural zones of the Earth have clear patterns of their location, extending in a latitudinal direction and changing from north to south. Most often, a change in natural zones is observed in the direction from the coast, making its way deep into the mainland.

In mountainous areas there is altitudinal zonality, which changes one zone for another, starting from the foot and moving towards the mountain peaks.

In the oceans, the change of zones occurs from the equator to the poles. Here, changes in natural zones are reflected in the surface composition of waters, as well as the difference in vegetation and wildlife.

Features of the natural zones of the continents

Since the planet Earth has a spherical surface, the Sun also heats it unevenly. Those areas of the surface above which the Sun is high receive the most heat. And where Sun rays only glide over the Earth - a more severe climate prevails.

And although vegetation and animals on different continents have similar features, they are influenced by climate, topography, geology and people. Therefore, it so happened historically that, due to changes in the relief and climate, different continents are inhabited by different types plants and animals.

There are continents where endemics are found, on which only certain kind living beings and plants that are peculiar to these continents. So, for example, polar bears can only be found in nature in the Arctic, and kangaroos in Australia. But in African and South American shrouds, similar species are found, although they have certain differences.

But human activity contributes to the changes that occur in the geographical shell, and under such influence, natural areas also change.

Questions and tasks for preparing for the exam

1. Map out the interaction natural ingredients in a natural complex and explain it.
2. How do the concepts “ natural complex”, “geographical shell”, “biosphere”, “natural zone”? Show with a diagram.
3. Name the zonal soil type for the tundra, taiga, zones of mixed and broad-leaved forests.
4. Where is the soil cover more difficult to restore: in the steppes of the South of Russia or in the tundra? Why?
5. What is the reason for the difference in the thickness of the fertile soil layer in different natural zones? What does soil fertility depend on?
6. What types of plants and animals are characteristic of the tundra and why?
7. What organisms live on the surface of the oceans?
8. Which of the following animals can be found in the African savannah: rhinoceros, lion, giraffe, tiger, tapir, baboon, llama, hedgehog, zebra, hyena?
9. In what forests is it impossible to find out its age from a cut of a cut tree?
10. What measures, in your opinion, will help preserve the human habitat?

Maksakovskiy V.P., Petrova N.N., Physical and economic geography of the world. - M.: Iris-press, 2010. - 368 pp.: ill.

What is a natural area? natural area- physical-geographical zone - is part of the geographic shell of the Earth and the geographic belt, has the characteristic components of its natural components and processes. What are natural areas?

1. Arctic (Antarctic) desert.
2. Forest tundra and tundra.
3. Taiga, mixed, deciduous forests, tropical forests.
4. Forest-steppe and steppe.
5. Deserts and semi-deserts.
6. Savannah.

Arctic and Antarctic deserts - such deserts occupy about 5 million square kilometers (the largest places are Greenland, Antarctica, the northern parts of Eurasia of North America), mainly consist of small rocks or scree, as well as glaciers. Feature there is no polar desert sunlight over a long period of time, approximately 10 months. Most of the soil is covered by permanent permafrost. The average temperature that happens in these areas is up to -30 degrees Celsius, in winter -60 degrees, in warm times year, the temperature is +3 degrees maximum. Such deserts are practically devoid of vegetation. Of the animals in the Arctic, polar bears, walruses, seals, arctic foxes, and seals live. In Alaska, Canada and Russia, the Arctic deserts are already gradually turning into tundra.

Forest-tundra and tundra - the largest areas of the tundra and forest-tundra are located in the north of North America and Eurasia (mainly Russia and Canada), mainly, such areas are located in the subarctic climatic zone. In the southern hemisphere of our planet, tundra and forest tundra are practically absent. The vegetation is very low, the most common are mosses and lichens. There are a large number of trees in the tundra, such as Siberian larch, dwarf birch, polar willow. Among the animals: deer, wolves, a large number of hares, arctic foxes. The average temperature in warm seasons is +5 +10 degrees, in winter the average temperature is -30 degrees. In the Tundra, winter can last up to 9 months. In the forest-tundra, the average temperature is +10 +15 degrees. In winter from -10 to -45 degrees. In the tundra and forest-tundra there are a very large number of lakes, due to high humidity, as well as a large number of swamps.

Taiga, mixed, deciduous forests, tropical forests - These areas are characterized by a mild climate and fertile soils. It is formed in temperate zones with an average amount of precipitation. Usually located in the temperate zone of Russia, Canada, Scandinavia. Characteristic Cold winter and pretty warm summer. From vegetation, a large number coniferous trees: pine, fir, larch, spruce. Taiga, has become famous for its dark coniferous boreal forests. There are also a large number deciduous trees: birch, poplar, aspen. The main seasons in the taiga and broad-leaved, tropical forests, is winter and summer. Autumn and spring are so short that you won't even notice that they exist. Taiga is either very cold or very hot. It happens that the temperature exceeds +30 degrees Celsius, mostly warm and rainy. In winter there are frosts and up to -50 degrees. A very large number of wild animals: brown bear, wolf, fox, wolverine, ermine, sable, there are deer, elk, roe deer. But usually, they live in an area where there is a very large number of deciduous trees.

Forest-steppe and steppe - these are areas of the earth's part that do not have forests, occupy quite vast territories in Eurasia, North America and in the subtropical belts of South America. Very low rainfall. The forest-steppe zone runs in the north between the steppes and forests in the north, namely, from the steppes, a transition is formed to semi-deserts, and then deserts begin. In the forest-steppes, just the opposite, there is a rather humid climate (up to 600 mm) than in the steppe, so such an element as the meadow steppe is formed here. The temperature in the steppes, as well as in the forest-steppes, is from -16 to +10 degrees in winter, +15 +30 degrees in summer. Vegetation usually changes from north to south, grasses are replaced by feather grass, and it is replaced by sagebrush. From animals there are ground squirrels, marmots, bustards, steppe eagles. There are also hedgehogs, squirrels, foxes, hares, snakes, moose, storks, beavers.

Deserts and semi-deserts this is one of the largest zones, it occupies one fifth of the earth's surface. It is clear that the largest part of these zones is located in the tropics (deserts and semi-deserts): in Africa, Australia, the tropics of South America, and also on the Arabian Peninsula in Eurasia. The driest desert is Atacama, which is located in Chile, there is practically no rain there. In the largest desert of the Earth - the Sahara, there is also very little rainfall, in summer the temperature can be up to +50 for deserts, this is a very common occurrence. There are frosts in winter. Deserts have almost no flora, due to the low humidity and very dry climate, there are very few plants that can survive in such a climate. There are enough animals: jerboas, ground squirrels, snakes, lizards, scorpions, camels.

Savannah such zones occur, for the most part, in the subequatorial belt of the Earth. The climate here is varied, sometimes very dry, and sometimes quite rainy. The average temperature for the year ranges from +15 to +25 degrees. The largest number of shrouds is located in South America, Africa, Indochina, the Hindustan Peninsula, the northern regions of Australia. Very diverse fauna, mostly herbaceous vegetation, various trees and shrubs. Of the animals that live in shrouds, the following can be distinguished: elephants, cheetahs, lions, rhinos, leopards, zebras, giraffes, antelopes. Lots of birds and insects.

natural area - a territory with close conditions of temperature and moisture, which determine generally homogeneous soils, vegetation and wildlife. On the plains, the zones extend in a latitudinal direction, regularly replacing each other from the poles to the equator. Often, significant distortions in the pattern of the zone are introduced by the relief and the ratio of land and sea.

Arctic and Antarctic deserts . These are cold deserts with very low air temperatures in the Arctic and Antarctica. In this zone, snow and ice persists almost all year round. In the warmest month - August - in the Arctic, the air temperature is close to 0°C. Ice-free spaces are bound by permafrost. Very intense frosty weathering. There is little precipitation - from 100 to 400 mm per year in the form of snow. In this zone, the polar night lasts up to 150 days. Summer is short and cold. Only 20 days, rarely 50 days a year the air temperature exceeds 0°C. The soils are thin, underdeveloped, stony, and placers of coarsely broken material are widespread. Less than half of the Arctic and Antarctic deserts are covered with sparse vegetation. It is devoid of trees and shrubs. Scale lichens, mosses, various algae, and only a few flowering plants are common here. The animal world is richer than the plant world. These are polar bears, arctic foxes, polar owls, deer, seals, walruses. Of the birds, there are penguins, eiders and many other birds that nest on rocky shores and form “bird colonies” in summer. In the zone of icy deserts, fishing for marine animals is carried out, among birds of particular interest is the eider, whose fluff is lined with nests. Eider down is harvested from abandoned nests to produce clothes worn by polar sailors and airmen. There are Antarctic oases in the icy desert of Antarctica. These are ice-free areas of the coastal strip of the mainland, with an area from several tens to hundreds of square meters. kilometers. The organic world of oases is very poor, there are lakes.

Tundra. This space lies within parts of the Arctic and subarctic belts in the Northern Hemisphere, while in the Southern Hemisphere tundra is common only on some islands. This is a territory with a predominance of moss-lichen vegetation, as well as low-growing perennial grasses, shrubs and low-growing shrubs. Trunks of shrubs and grass roots are hidden in moss and lichen turf.

The climate of the tundra is severe, the average July temperature only in the south of the natural zone does not exceed +11°C, the snow cover lasts 7-9 months. Precipitation is 200-400 mm, and in some places up to 750 mm. main reason treeless tundra - low air temperatures combined with high relative humidity, strong winds, widespread permafrost. In the tundra there are also unfavorable conditions for the germination of seeds of woody plants on a moss-lichen cover. Plants in the tundra are pressed against the surface of the soil, forming densely intertwined shoots in the form of a pillow. In July, the tundra is covered with a carpet of flowering plants. Due to excessive moisture and permafrost, there are many swamps in the tundra. On the warmed banks of rivers and lakes, you can find poppies, dandelions, polar forget-me-nots, and pink flowers of mytnik. According to the prevailing vegetation in the tundra, 3 zones are distinguished: arctic tundra , characterized by sparse vegetation due to the severity of the climate (in July + 6 ° C); moss-lichen tundra , characterized by richer vegetation (in addition to mosses and lichens, sedge, bluegrass, creeping willow are found here), and shrub tundra , located in the south of the tundra zone and characterized by richer vegetation, which consists of thickets of willow and alder shrubs, which in places rise to the height of a person. In areas of this subzone, bush is an important source of fuel. The soil of the tundra zone is predominantly tundra-gley, characterized by gleying (see "Soils"). She is infertile. Frozen soils with a thin active layer are ubiquitous. The fauna of the tundra is represented by reindeer, lemming, arctic fox, ptarmigan, and in summer - many migratory birds. Shrub tundra gradually turns into forest tundra.

forest tundra . This is a transitional zone between the tundra and the temperate forest zone. It is distributed in the Northern Hemisphere in North America and Eurasia. The climate is less severe than in the tundra: the average July temperature here is +10-14°C. The annual rainfall is 300-400 mm. Precipitation in the forest tundra falls more than evaporates, so the forest tundra is characterized by excessive moisture, it is one of the most swampy natural zones. The snow cover lasts for more than six months. High water on the rivers of the forest-tundra usually occurs in summer, since the rivers of this zone are fed by melt water, and snow melts in the forest-tundra in summer. The woody vegetation that appears in this zone grows along the river valleys, as rivers have a warming effect on the climate of this zone. Islands of forests consist of birch, spruce, larch. The trees are stunted, sometimes bent to the ground. The forest area increases in the forest-tundra when moving south along it. In the interfluves, there are stunted and sparse forests. Thus, the forest-tundra is an alternation of treeless shrublands and light forests. Soils are tundra (peat-bog) or forest. The fauna of the forest-tundra is similar to the fauna of the tundra. Arctic foxes, white partridges, snowy owls and a wide variety of migratory waterfowl also live here. The main winter reindeer pastures and hunting grounds are located in the forest-tundra.

temperate forests . This natural zone is located in the temperate climate zone and includes subzones taiga, mixed and deciduous forests, monsoon forests temperate zone. Differences in climatic features contribute to the formation of vegetation characteristic of each subzone.

Taiga (Turk.). This zone coniferous forests located in the north of North America and in the north of Eurasia. The climate of the subzone is from maritime to sharply continental with relatively warm summers (from 10°С to 20°С), and the lower the winter temperatures, the more continental the climate is (from -10°С in northern Europe to -50°С in northeastern Siberia). Permafrost is widespread in many regions of Siberia. The subzone is characterized by excessive moisture and, as a result, swampiness of interfluve spaces. There are two types of taiga: light coniferous and topicsconiferous. Light coniferous taiga - these are the least demanding pine and larch forests in terms of soil and climatic conditions, the sparse crown of which transmits the sun's rays to the ground. Pines, having a branched root system, have acquired the ability to use nutrients from infertile soils, which is used to fix soils. This feature allows these plants to grow in areas with permafrost. The shrub layer of the light coniferous taiga consists of alder, dwarf birches, polar birches, polar willows, and berry bushes. This type of taiga is common in Eastern Siberia. dark coniferous taiga - These are conifers, consisting of numerous species of spruce, fir, cedar. This taiga, unlike the light coniferous one, has no undergrowth, since its trees are tightly closed, and it is rather gloomy in these forests. The lower tier is made up of shrubs (lingonberries, blueberries, blueberries) and dense ferns. This type of taiga is common in the European part of Russia and Western Siberia.

Soils taiga zone podzolic. They contain little humus, but when fertilized they can provide a high yield. In the taiga of the Far East - acidic soils.

The fauna of the taiga zone is rich. Numerous predators are found here, which are valuable game animals: otter, marten, sable, mink, weasel. Of the large ones - wolves, bears, lynxes, wolverines. In North America, bison and elk deer used to be found in the taiga zone. Now they live only in reserves. The taiga is also rich in rodents, of which the most typical are beavers, muskrats, squirrels, hares, and chipmunks. The world of birds is very diverse.

Mixed temperate forests . These are forests with various tree species: coniferous-broad-leaved, small-leaved-pine. This zone is located in the north of North America (on the border of the USA and Canada), and in Eurasia it forms a narrow strip between the taiga and the zone of deciduous forests. The zone of mixed forests is also found in Kamchatka and the Far East. In the Southern Hemisphere, this forest zone occupies small areas in southern South America and New Zealand.

The climate of the zone of mixed forests is maritime or transitional to continental (toward the center of the mainland), summers are warm, winters are moderately cold (in a maritime climate with positive temperatures, and in a more continental climate up to -10 ° C). Moisture here is sufficient. The annual amplitude of temperature fluctuations, as well as the annual amount of precipitation, vary from oceanic regions to the center of the continent.

The diversity of vegetation in the zone of mixed forests of the European part of Russia and the Far East is explained by differences in climate. For example, on the Russian Plain, where precipitation falls all year round due to westerly winds coming from the Atlantic, European spruce, oak, elm, fir, and beech are common - coniferous-broad-leaved forests.

The soils in the zone of mixed forests are gray forest and sod-podzolic, and in the Far East they are brown forest.

The animal world is similar to the animal world of the taiga and the zone of deciduous forests. Elk, sable, bear live here.

Mixed forests have long been subjected to heavy cutting and losses. They are best preserved in North America and the Far East, and in Europe they are cut down for agricultural land - field and pasture land.

Temperate broadleaf forests . They occupy the east of North America, Central Europe, and also form a high-altitude zone in the Carpathians, Crimea and the Caucasus. In addition, individual foci of broad-leaved forests are found in the Russian Far East, Chile, New Zealand, and central Japan.

The climate is favorable for the growth of deciduous trees with a wide leaf plate. Here, temperate continental air masses bring precipitation from the oceans (from 400 to 600 mm) mainly in the warm season. The average temperature in January is -8°-0°С, and in July +20-24°С.

Beech, hornbeam, elm, maple, linden, ash grow in the forests. In the zone of deciduous forests of North America, there are species that are absent on other continents. These are American oak species. Trees with a powerful spreading crown predominate here, often entwined with climbing plants: grapes or ivy. To the south there are magnolias. For European broad-leaved forests, oak and beech are most typical.

The fauna of this natural zone is close to the taiga, but there are such animals as black bears, wolves, minks, raccoons, which are not typical for the taiga. Many animals of the broad-leaved forests of Eurasia are under protection, as the number of individuals is sharply reduced. These include such animals as the bison, the Ussuri tiger.

Soils under deciduous forests are gray forest or brown forest. This zone has been heavily developed by man, forests have been cleared over large areas, and the land has been plowed up. In its true form, the zone of broad-leaved forests has been preserved only in areas inconvenient for arable farming and in reserves.

forest-steppe . This natural zone is located within the temperate climate zone and represents a transition from forest to steppe, with alternating forest and steppe landscapes. It is distributed in the Northern Hemisphere: in Eurasia from the Danubian lowland to Altai, further in Mongolia and the Far East; in North America, this zone is located in the north of the Great Plains and in the west of the Central Plains.

The forest-steppes are naturally distributed within the continents between the forest zones, which choose the most humid areas here, and the steppe zone.

The climate of the forest-steppes is temperate continental: winters are snowy and cold (from -5°С to -20°С), summers are warm (+18°С to +25°С). In different longitudinal zones, the forest-steppe differs in precipitation (from 400 mm to 1000 mm). Humidification is slightly lower than sufficient, evaporation is very high.

In the forests, which are interspersed with steppe ones, broad-leaved (oak) and small-leaved tree species (birch) are more common, less often - conifers. The soils of the forest-steppe are mainly gray forest soils, which alternate with chernozems. The nature of the forest-steppe zone has been greatly changed by human economic activity. In Europe and North America, the plowing of the zone reaches 80%. Since this zone has fertile soils, wheat, corn, sunflower, sugar beet and other crops are grown here. The fauna of the forest-steppe zone includes species characteristic of the forest and steppe zones.

The West Siberian forest-steppe is specific with numerous birch groves-pegs (singular number - pegs). Sometimes they have an admixture of aspen. The area of ​​individual pegs reaches 20-30 ha. Numerous pegs, alternating with areas of steppes, create a characteristic landscape of Southwestern Siberia.

steppes . This is a landscape with a grassy type of vegetation, located in the temperate and partly in the subtropical zone. In Eurasia, the steppe zone extends latitudinally from the Black Sea to Transbaikalia; in North America, the Cordillera distribute air currents in such a way that the zone of insufficient moisture, and with it the steppe zone, is located from north to south along the eastern outskirts of this mountainous country. In the Southern Hemisphere, the steppe zone is located within the subtropical climate, in Australia and Argentina. Precipitation(from 250 mm to 450 mm per year) fall here irregularly and are insufficient for the growth of trees. The winter is cold, the average temperature is below 0°С, in some places up to -30°, with little snow. Summer is moderately hot - +20°С, +24°С, drought is not uncommon. Inland waters in the steppe are poorly developed, river flow is small, and rivers often dry up.

The undisturbed vegetation of the steppe is a dense grass cover, but the undisturbed steppes all over the world have remained only in reserves: all the steppes are plowed up. Depending on the nature of the vegetation in the steppe zone, three subzones are distinguished. They differ from each other in the prevailing vegetation. it meadow steppes (bluegrass, bonfire, timothy grass), cereals and southern wormwood-cereal .

The soils of the steppe zone - chernozems - have a significant humus horizon, due to which they are very fertile. This is one of the reasons for the strong tillage of the zone.

The fauna of the steppes is rich and varied, but it has changed a lot under the influence of man. Back in the 19th century, wild horses, aurochs, bison, and roe deer disappeared. Deer are pushed back into the forests, saigas - into the virgin steppes and semi-deserts. Now the main representatives of the animal world of the steppes are rodents. These are ground squirrels, jerboas, hamsters, voles. Occasionally there are bustards, little bustards, larks and others.

The steppes and partly the forest-steppes of the temperate and subtropical zones of North America are called prairies . At present, they are almost completely plowed up. Part of the American prairie is dry steppe and semi-desert.

The subtropical steppe on the plains of South America, located mainly in Argentina and Uruguay, is called pampa . In the eastern regions, where precipitation is brought from the Atlantic Ocean, moisture is sufficient, and aridity increases to the west. Most of the pampas have been plowed up, but in the west there are still dry steppes with thorny bushes used as pastures for livestock.

Semi-deserts and temperate deserts . In the south, the steppes pass into semi-deserts, and then into deserts. Semi-deserts and deserts are formed in a dry climate, where there is a long and hot warm period (+20-25°С, sometimes up to 50°С), strong evaporation, which is 5-7 times higher than the amount of annual precipitation (up to 300 mm in year). Weak surface runoff, poor development inland waters, many drying channels, vegetation is not closed, sandy soils heat up during the day, but quickly cool down on a cool night, which contributes to physical weathering. The winds dry up the land very strongly here. The deserts of the temperate zone differ from the deserts of other geographical zones in more cold winter(-7°C-15°C). Deserts and semi-deserts of the temperate zone are common in Eurasia from the Caspian lowland to the northern bend of the Huang He, and in North America - in the foothills and basins of the Cordilleras. In the Southern Hemisphere, deserts and semi-deserts of the temperate zone are found only in Argentina, where they are found in broken areas in the interior and foothills. Of the plants here there are steppe feather grass, fescue, wormwood and saltwort, camel thorn, agave, aloe. Of the animals - saigas, turtles, many reptiles. The soils here are light chestnut and brown desert, often saline. Under conditions of sharp fluctuations in temperature during the day, with little moisture, a dark crust forms on the surface of the desert - desert tan. It is sometimes called protective, as it protects rocks from rapid weathering and destruction.

The main use of semi-deserts is grazing (camels, fine-fleeced sheep). Farming of drought-resistant crops is possible only in oases. An oasis (from the Greek name of several inhabited places in the Libyan Desert) is a place of growth of tree, shrub and herbaceous vegetation in deserts and semi-deserts, in conditions of more abundant surface and soil moisture compared to neighboring areas and areas. The sizes of oases are different: from ten to tens of thousands of kilometers. Oases - centers of population concentration, areas of intensive agriculture on irrigated lands (Nile Valley, Ferghana Valley in Central Asia).

Deserts and semi-deserts of the subtropical and tropical zones . These are natural zones located in both hemispheres, on all continents along tropical zones of high atmospheric pressure. Most often, the semi-deserts of the subtropical belt are located in the transitional part from deserts to mountain steppes in the form of an altitudinal belt in the inland parts of the Cordilleras and the Andes of America, in western Asia, Australia, and especially widely in Africa. The climate of deserts and semi-deserts of these climatic zones is hot: the average temperature in summer rises to +35°С, and in the coldest months of winter it does not fall below +10°С. Precipitation is 50-200 mm, in semi-deserts up to 300 mm. Precipitation sometimes falls in the form of short showers, and in some areas precipitation may not fall for several years in a row. With a lack of moisture, the weathering crust is very thin.

Groundwater is very deep and may be partially saline. In such conditions, only plants that can tolerate overheating and dehydration can live. They have a deeply branched root system, small leaves or spines that reduce evaporation from the leaf surface. In some plants, the leaves are pubescent or covered with a wax coating, which protects them from sunlight. In the semi-deserts of the subtropical zone, cereals are common, cacti appear. In the tropical zone, the number of cacti increases, agaves, sand acacias grow, various lichens are common on stones. A characteristic plant for the Namib Desert, located in the tropical belt of South Africa, is amazing plant velwigia, which has a short trunk, from the top of which two leathery leaves extend. The age of velwigia can reach 150 years. The soils are rubbly serozems, gray-brown, they are not very fertile, since the layer of humus is thin. The fauna of deserts and semi-deserts is rich in reptiles, spiders, scorpions. There are camels, antelopes, rodents are quite widespread. Agriculture in semi-deserts and deserts of the subtropical and tropical zones is also possible only in oases.

hardwood forests . This natural zone is located within the subtropical zone of the Mediterranean type. They mainly grow in southern Europe, northern Africa, southwest and southeast Australia. Separate fragments of these forests are found in California, in Chile (south of the Atacama Desert). Hardwood forests grow in a mild temperate warm climate with hot (+25°C) and dry summers and cool and rainy winters. The average amount of precipitation is 400-600 mm per year with rare and short-lived snow cover. The rivers are mainly rain-fed, and the flood occurs during the winter months. In rainy winter conditions, grasses grow rapidly.

The animal world is strongly exterminated, but herbivorous and leaf-eating forms, many birds of prey and reptiles are characteristic. In the forests of Australia, you can meet the koala bear, which lives in trees and leads a nocturnal sedentary lifestyle.

The territory of hardwood forests is well developed and largely changed by human economic activity. Large areas of forests have been cut down here, and oilseed plantations, orchards and pastures have taken their place. Many tree species have solid wood, which is used as a building material, and oils, paints, medicines (eucalyptus) are made from leaves. Large harvests of olives, citrus fruits, grapes are taken from the plantations of this zone.

Monsoon forests of the subtropical zone . This natural area is located in the eastern parts of the continents (China, southeastern United States, eastern Australia, southern Brazil). It is located in the most humid conditions compared to other zones of the subtropical belt. The climate is characterized by dry winters and wet summers. Annual rainfall is greater than evaporation. The maximum amount of precipitation falls in the summer due to the influence of the monsoons, which bring moisture from the ocean. On the territory of monsoon forests, internal waters are quite rich, fresh groundwater is shallow.

Here, on red soils and yellow soils, high-stemmed mixed forests grow, among which there are evergreen and deciduous, shedding foliage in the dry season. The species composition of plants may vary depending on the soil conditions. Subtropical species of pines, magnolias, camphor laurel, and camellias grow in the forests. On the flooded coasts of Florida in the United States and on the Mississippi lowlands, swamp cypress forests are common.

The monsoon forest zone of the subtropical belt has long been mastered by man. Field and pasture lands are located on the site of the reduced forests; rice, tea, citrus fruits, wheat, corn and industrial crops are grown here.

Forests of the tropical and subequatorial belts . They are located along the east of Central America, in the Caribbean, on the island of Madagascar, in southeast Asia, and in northeast Australia. Two seasons are distinctly expressed here: dry and wet. The existence of forests in the dry and hot tropical zone is possible only thanks to the precipitation that the monsoons bring in summer from the oceans. In the subequatorial belt, precipitation comes in summer, when equatorial air masses dominate here. Depending on the degree of moisture, among the forests of the tropical and subequatorial belts, there are permanently wet and seasonally wet(or variable-moist) forests. Seasonally humid forests are characterized by a relatively poor species composition of tree species, especially in Australia, where these forests consist of eucalyptus, ficus, and laurel. Often in seasonally wet forests there are areas where teak and sal grow. There are very few in the forests of this group of palm trees. In terms of their species diversity of flora and fauna, permanently humid forests are close to equatorial ones. There are many palms, evergreen oaks, tree ferns. Many vines and epiphytes from orchids and ferns. Soils located under the forests are mostly lateritic. During the dry season (winter) most deciduous trees do not shed all their leaves, but some species remain completely bare.

Savannah . This natural zone is located mainly within the subequatorial climate, although it is also within the tropical and subtropical zones. In the climate of this zone, the change of the wet and dry seasons is clearly expressed at consistently high temperatures (from + 15°С to + 32°С). As you move away from the equator, the period of the wet season decreases from 8-9 months to 2-3, and precipitation - from 2000 to 250 mm per year.

The savannas are characterized by the predominance of grassy cover, among which high (up to 5 m) grasses dominate. Shrubs and single trees rarely grow among them. The grass cover near the borders with the equatorial belt is very dense and high, and sparse near the borders with semi-deserts. A similar pattern can be traced in trees: their frequency increases towards the equator. Among the savannah trees you can find a variety of palm trees, umbrella acacias, tree-like cacti, eucalyptus, water-storing baobabs.

Savannah soils depend on the length of the rainy season. Closer to the equatorial forests, where the rainy season lasts up to 9 months, there are red ferralitic soils. Closer to the border of savannahs and semi-deserts, red-brown soils are located, and even closer to the border, where it rains for 2-3 months, unproductive soils with a thin layer of humus are formed.

The fauna of the savannas is very rich and diverse, as the high grass cover provides animals with food. Elephants, giraffes, hippos, zebras live here, which in turn attract lions, hyenas and other predators. The world of birds of this zone is also rich. Sunbirds live here, ostriches - the largest birds on Earth, a secretary bird that hunts for small animals and reptiles. Many in the savanna and termites.

Savannahs are widespread in Africa, where they occupy 40% of the mainland, in South America, Australia and India.

Tall-grass savannahs in South America, on the left bank of the Orinoco River, with a dense, mainly grassy grass cover, with individual specimens or groups of trees, are called llanos (from the Spanish plural "plains"). The savannas of the Brazilian Plateau, where the region of intensive animal husbandry is located, are called campos .

Today, savannahs play a very important role in the economic life of man. Significant areas of this zone have been plowed up; cereals, cotton, peanuts, jute, and sugar cane are grown here. Animal husbandry is developed in drier places. Breeds of many trees are used on the farm, as their wood does not rot in water. Human activity often leads to desertification of the savannas.

Moist equatorial forests . This natural zone is located in an equatorial and partly subequatorial climate. These forests are common in the Amazon, the Congo, the Malay Peninsula and the Sunda Islands, as well as other smaller islands.

The climate here is hot and humid. All year round the temperature is +24-28°С. The seasons are not expressed here. Moist equatorial forests are located within a low pressure area, where, as a result of intense heating, ascending air currents are formed and a lot of precipitation (up to 1500 mm per year.) Falls throughout the year.

On the coasts, where the wind from the ocean influences, precipitation is even more (up to 10,000 mm). Precipitation falls evenly throughout the year. Such climatic conditions contribute to the development of lush evergreen vegetation, although, strictly speaking, trees change leaves: some of them are shed every six months, others after a completely arbitrary period, and others change leaves in parts. Flowering periods also vary, and even more erratically. The most frequent cycles are ten and fourteen months. Other plants may bloom once every ten years. But at the same time, plants of the same species bloom at the same time so that they have time to pollinate each other. Plants in this zone have little branching.

Trees of humid equatorial forests have disc-shaped roots, large leathery leaves, the shiny surface of which saves them from excessive evaporation and the scorching rays of the sun, from the impact of rain jets during heavy showers. Many leaves end in a graceful thorn. This is a tiny drain. In plants of the lower tier, the leaves, on the contrary, are thin and delicate. The upper tier of equatorial forests is formed by ficuses and palms. In South America, ceiba grows in the upper tier, reaching a height of 80 m. Bananas and tree ferns grow in the lower tiers. Large plants are entwined with vines. There are many orchids on the trees of the equatorial forests, epiphytes are found, sometimes flowers form directly on the trunks. For example, the flowers of the cocoa tree. In the forest of the equatorial zone, it is so hot and humid that favorable conditions are created for the development of moss and algae, which adhere to the crown and hang from the branches. They are epiphytes. The flowers of trees in the crown cannot be pollinated by the wind, because the air there is practically still. Consequently, they are pollinated by insects and small birds, which are lured by a brightly colored corolla or a sweet scent. The fruits of plants are also brightly colored. This allows them to solve the problem of transporting seeds. The ripe fruits of many trees are eaten by birds, animals, the seeds are not digested and, together with the droppings, are far from the parent plant.

There are many host plants in the equatorial forests. First of all, these are vines. They begin their life on the ground in the form of a small bush, and then, tightly wrapping themselves around the stem of a giant tree, they climb up. The roots are in the soil, so the plant is not fed by a giant tree, but sometimes the use of these trees for support by vines can lead to oppression and death. "Robbers" are some ficuses. Their seeds germinate on the bark of a tree, the roots tightly wrap around the trunk and branches of this host tree, which begins to die. Its trunk is rotting, but the roots of the ficus have become thick and dense and are already able to support themselves.

The equatorial forests are home to many valuable plants, such as the oil palm, from which palm oil is obtained. The wood of many trees is used to make furniture and is exported in large quantities. This group includes ebony, the wood of which is black or dark green. Many plants of the equatorial forests give valuable fruits, seeds, juice, bark, which are used in technology and medicine.

The equatorial forests of South America are called selva . Selva is located in the periodically flooded area of ​​the Amazon River Basin. Sometimes, when describing humid equatorial forests, the name is used hylaea , sometimes these forests are called jungle , although, strictly speaking, the jungle is called the forest thickets of South and Southeast Asia, located within the subequatorial and tropical climate.