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 “continent” and “ocean” were formed. But the nature of each continent, like each ocean, is not the same. Their territories contain various natural zones.
A natural zone is a large natural complex that has common temperature and moisture conditions, soils, vegetation and fauna. The formation of zones is determined by climate, on land - by 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 is formed equatorial forests. If temperatures are high and there is little precipitation, then a tropical desert zone is formed.
Natural areas Sushi differ in appearance from each other by the nature of their vegetation. The vegetation of the zones, of all the components of nature, most clearly expresses everything the most important features their nature, the relationship between the components. If changes occur in individual components, then externally this affects primarily the change in vegetation. Natural land areas are named according to the nature of their vegetation, for example desert zones, equatorial forests, etc.
Rice. 33. Natural zones of the World Ocean
The World Ocean also has natural zones (natural zones). They differ water masses, organic world etc. Natural zones of the ocean do not have clear external differences, with the exception of ice cover, and are named after their geographical location, as well as climatic zones(Fig. 33).
Patterns of location of natural zones on Earth. In the placement of natural areas on earth's surface Scientists have discovered a clear pattern that can be clearly seen on the map of natural areas. To understand this pattern, let us trace on the map the change in natural zones from north to south along 20° east. e. In the subarctic zone, where temperatures are low, there is a zone of tundra and forest-tundra, giving way to taiga to the south. There is enough heat and moisture here for the growth of coniferous trees. In the southern half temperate zone The amount of heat and precipitation increases significantly, which contributes to the formation of a zone of mixed and deciduous 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. Next we find ourselves in the tropical zone. Here, in the sun-scorched expanses, it is scorching, the vegetation is sparse and stunted, and in some places completely absent. This is a tropical desert area. To the south it gives way to savannas - tropical forest-steppes, where there is already a wet season and a lot of heat. But the amount of precipitation is not enough for forest growth. In the equatorial climate zone there is a lot of heat and moisture, so a zone of humid equatorial forests with very rich vegetation is formed. IN South Africa zones, like climate zones, repeat themselves.
Rice. 34. Particularly beautiful blooming steppe in the spring
In Antarctica there is a zone of the Antarctic desert, characterized by exceptional severity: very low temperatures and strong winds.
So, you are apparently convinced that the alternation of natural zones on the plains is explained by the change 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 trace on the map the change of zones in Eurasia from west to east along the 45th parallel - in the temperate zone.
On the coast Atlantic Ocean, where marine air masses coming from the ocean dominate, there is a zone of deciduous forests, beech, oak, linden, etc. grow. When moving to the east forest zone is replaced by a zone of forest-steppes and steppes. The reason is a decrease in precipitation. Even further to the east, precipitation becomes less and the steppes turn into deserts and semi-deserts, which further to the east again give way to steppes, and near Pacific Ocean- 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 for the same reasons - a change in the ratio of heat and moisture, which is determined by 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, movement air masses, currents.
Latitudinal zoning. The location of natural zones is closely related to climatic zones. Like climate zones, they naturally replace each other from the equator to the poles due to a decrease in solar heat reaching the Earth's surface and uneven moisture. This change of natural zones - large natural complexes is called latitudinal zonality. Zoning is evident in all natural complexes regardless of their size, as well as in all components of the geographical envelope. Zoning is a basic geographical pattern.
Rice. 36. Coniferous forest
Altitudinal zone. A change in 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 altitude the amount of precipitation increases, and lighting conditions change. Due to changing climatic conditions, natural zones are also changing. The zones replacing one another seem to encircle the mountains for different heights, which is why they are called high-altitude zones. Change altitude zones in the mountains occurs much faster than the change of zones on the plains. It is enough to climb 1 km to see 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 peak you will find the following altitude zones: taiga, mountain tundra, eternal snow. If you have to climb the Andes near the equator, then you will begin your journey from the belt (zone) of equatorial forests. The pattern is this: the higher the mountains and the closer they are to the equator, the more altitude zones there are and the more diverse they are. In contrast to zonality on the plains, the alternation of natural zones in the mountains is called altitudinal zonation or altitudinal zonation.
Rice. 37. Savannah in the dry season
The law of geographic zoning also manifests itself in mountainous areas. We have already considered some of them. From geographical latitude depends on the change of day and night, seasonal changes. If the mountain is located 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 “natural area”.
- What are the features of the location of natural areas on continents and in the ocean?
- What is latitudinal zonation and altitudinal zonation?
- In which mountains is there greatest number altitudinal zones, in which - the least? Why?
The natural complexes of the Earth are very diverse. These are hot and icy deserts, evergreen forests, endless steppes, and bizarre mountains. This diversity is the unique beauty of our planet.
You already know how natural complexes, “continents”, “oceans” were formed. But the nature of each continent, like each ocean, is not the same. Various natural zones are formed on their territory.
Topic: Nature of the Earth
Lesson: Natural Areas of the Earth
Why are natural areas formed?
On the patterns of distribution of natural zones,
Features of natural zones of continents.
Thus, the annual precipitation amount is 200 mm in the cold subarctic zone - excessive moisture, which leads to the formation of swamps (see Fig. 1).
And in hot tropical zones it is sharply insufficient: deserts are formed (see Fig. 2).
Due to differences in the amount of solar heat and moisture, natural zones are formed within geographic zones.
There is a clear pattern in the distribution of natural zones on the earth's surface, which is clearly visible on the map of natural zones. They extend in the latitudinal direction, replacing each other from north to south.
Due to the heterogeneity of the relief of the earth's surface and moisture conditions in different parts On continents, natural zones do not form continuous strips parallel to the equator. More often they change in the direction from the coasts of the oceans to the interior of the continents. In the mountains, natural zones replace each other from the foothills to the peaks. This is where the altitudinal zone appears.
Natural zones are also formed in the World Ocean: from the equator to the poles, the properties of surface waters, the composition of vegetation and fauna change.
Rice. 3. Natural areas of the world ()
In the same natural areas on different continents flora and fauna have similar features.
However, in addition to climate, other factors also influence the distribution of plants and animals: geological history continents, relief, people.
The unification and separation of continents, changes in their topography and climate in the geological past became the reason that they live in similar natural conditions, but on different continents different types animals and plants.
For example, African savannas are characterized by antelopes, buffalos, zebras, and African ostriches, and in South American savannas several species of deer and the ostrich-like flightless bird rhea are common.
On every continent there are endemics - both plants and animals that are unique to that continent. For example, kangaroos are found only in Australia, and polar bears are found only in the Arctic deserts.
Geofocus
The Sun heats the spherical surface of the Earth unequally: the areas above which it stands high receive the most heat.
Above the poles, the rays of the Sun only glide over the Earth. The climate depends on this: hot at the equator, harsh and cold at the poles. The main features of the distribution of vegetation and fauna are also associated with this.
Moist evergreen forests are located in narrow stripes and spots along the equator. “Green Hell” - this is what many travelers of past centuries who visited here called these places. Tall multi-tiered forests stand like a solid wall, under the thick crowns of which there is constantly darkness, monstrous humidity, constant high temperatures, there is no change of seasons, and rainfalls regularly fall with an almost continuous stream of water. The forests of the equator are also called permanent rain forests. Traveler Alexander Humboldt called them “hyleia” (from the Greek hyle - forest). Most likely, this is what the humid forests of the Carboniferous period looked like with giant ferns and horsetails.
Rain forests South America called “selva” (see Fig. 4).
Rice. 4. Selva
Savannas are a sea of grasses with rare islands of trees with umbrella crowns (see Fig. 5). Vast areas of these amazing natural communities are located in Africa, although there are savannas in South America, Australia, and India. A distinctive feature of savannas is the alternation of dry and wet seasons, which take about six months, replacing each other. The fact is that subtropical and tropical latitudes, where savannas are located, are characterized by a change in two different air masses - humid equatorial and dry tropical. The monsoon winds, which bring seasonal rains, significantly influence the climate of the savannas. Because these landscapes are located between the very wet natural zones of equatorial forests and the very dry zones of deserts, they are constantly influenced by both. But moisture is not present long enough in savannas for multi-tiered forests to grow there, and arid ones “ winter periods"in 2-3 months they do not allow the savannah to turn into a harsh desert.
The natural taiga zone is located in the north of Eurasia and North America (see Fig. 6). On the North American continent it stretches from west to east for more than 5 thousand km, and in Eurasia, starting on the Scandinavian Peninsula, it spread to the shores of the Pacific Ocean. The Eurasian taiga is the largest continuous forest zone on Earth. It occupies more than 60% of the territory Russian Federation. The taiga contains huge reserves of wood and supplies a large number of oxygen into the atmosphere. In the north, the taiga smoothly turns into forest-tundra, gradually taiga forests give way to open forests, and then separate groups trees. The taiga forests extend farthest into the forest-tundra along river valleys, which are most protected from strong northern winds. In the south, the taiga also smoothly transitions into coniferous-deciduous and broad-leaved forests. In these areas, humans have interfered with the natural landscapes for many centuries, so now they represent a complex natural-anthropogenic complex.
Under influence human activity The geographic environment is changing. Swamps are drained, deserts are irrigated, forests disappear, and so on. This changes the appearance of natural areas.
Homework
Read § 9. Answer the questions:
· What determines the moisture content of an area? How various conditions Do moisturizers affect natural complexes?
· Are there natural areas in the ocean?
Bibliography
MainI
1. Geography. Land and people. 7th grade: Textbook for general education. uch. / A.P. Kuznetsov, L.E. Savelyeva, V.P. Dronov, series “Spheres”. - M.: Education, 2011.
2. Geography. Land and people. 7th grade: atlas, “Spheres” series.
Additional
1. N.A. Maksimov. Behind the pages of a geography textbook. - M.: Enlightenment.
Literature for preparing for the State Exam and the Unified State Exam
1. Tests. Geography. 6-10 grades: Educational and methodological manual/ A. A. Letyagin. - M.: LLC "Agency "KRPA "Olympus": Astrel, AST, 2007. - 284 p.
2. Tutorial by geography. Tests and practical assignments in geography / I. A. Rodionova. - M.: Moscow Lyceum, 1996. - 48 p.
3. Geography. Answers on questions. Oral exam, theory and practice / V. P. Bondarev. - M.: Publishing house "Exam", 2009. - 160 p.
4. Thematic tests to prepare for the final certification and the Unified State Exam. Geography. - M.: Balass, ed. House of RAO, 2011. - 160 p.
1. Russian geographical society ().
3. Textbook on geography ().
4. Gazetteer ().
5. Geological and geographical formation ().
Zoning - changes in natural components and the natural complex as a whole from the equator to the poles. Zoning is based on various receipts heat, light, and precipitation to the Earth, which, in turn, are already reflected in all other components, and above all, soils, vegetation and wildlife.
Zoning is characteristic of both land and the World Ocean.
The largest zonal divisions of the geographical envelope are geographical zones. The 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 zones 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 common vegetation, soils and fauna.
You are already familiar with the arctic desert zone, tundra, temperate forest zone, steppes, deserts, wet and dry subtropics, savannas, moist evergreen equatorial forests.
Within natural areas there are transition areas. They are formed due to gradual change climatic conditions. To such transition zones include, for example, forest-tundra, forest-steppe and semi-deserts.
Zoning is not only latitudinal, but also vertical. Vertical zoning- a natural change in natural complexes in height and depth. For mountains, the main reason for this zonation is the change in temperature and amount of moisture with height, and for the depths of the ocean - heat and sunlight.
The change in natural zones depending on the height above sea level in mountainous areas is called, as you already know, altitudinal zone.
It differs from horizontal zoning in the length of the belts and the presence of a belt of alpine and subalpine meadows. The number of belts usually increases in high mountains and as it approaches the equator.
Natural areas
Natural areas- large subdivisions of the geographical envelope, having a certain combination of temperature conditions and moisture regime. They are classified mainly according to the predominant type of vegetation and change naturally on the plains from north to south, and in the mountains - from the foothills to the peaks. Natural zones of Russia are presented in Fig. 1.
The latitudinal distribution of natural zones on the plains is explained by the flow of unequal amounts of solar heat and moisture onto the earth's surface at different latitudes.
The resources of flora and fauna of natural zones are biological resources territories.
The set of altitudinal zones depends primarily on what latitude the mountains are located at and what their height is. It should also be noted that for the most part the boundaries between altitudinal zones are not clear.
Let us consider in more detail the features of the location of natural zones using the example of the territory of our country.
polar desert
The very north of our country - the Northern Islands Arctic Ocean— located in a natural area polar (arctic) deserts. This zone is also called ice zone. The southern border approximately coincides with the 75th parallel. The natural zone is characterized by the dominance of Arctic air masses. 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 is at a latitude of 75° N. w. lasts 98 days.
In summer, even round-the-clock lighting is not able to provide this area with enough heat. The air temperature rarely rises above 0 °C, and the average temperature in July is +5 °C. There may be drizzle for several days, but there are practically no thunderstorms or 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 glacial areas of land where vegetation develops are small areas. Mosses and crustose lichens “settle” on placers of pebbles, fragments of basalt and boulders. Occasionally there are poppies and saxifrages, which begin to bloom when the snow has barely melted.
The fauna of the Arctic desert is mainly represented by marine inhabitants. These are the harp seal, walrus, ringed seal, bearded seal, beluga whale, porpoise, and killer whale.
Diverse in northern seas species of baleen whales. Blue and bowhead whales, sei whales, fin whales, and humpback whales are rare and endangered species and are listed in the Red Book. Inner side the long horny plates that replace teeth for whales are split into hairs. This allows the animals to filter large volumes of water, extracting plankton, which 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, Fr. 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 weather stations operating here monitor the weather and the movement of ice in the ocean. On the islands they hunt Arctic fox in winter and game birds in summer. Fishing is carried out in the waters of the Arctic Ocean.
Steppes
To the south of the forest-steppe zone there are steppes. 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, steppe areas have a focal distribution.
The climate of the steppes is moderate continental, but drier than in the zone of forests and forest-steppes. Number of annual total solar radiation reaches 120 kcal/cm2. The average January temperature in the sun is -2 °C, and in the east -20 °C and below. Summer in the steppe is sunny and hot. The average temperature in July is 22-23 °C. The sum of active temperatures is 3500 °C. Precipitation is 250-400 mm per year. In summer there are frequent showers. The humidification coefficient is less than one (from 0.6 in the north of the zone to 0.3 in the southern steppes). Stable snow cover lasts up to 150 days a year. In the west of the zone there are often thaws, so the snow cover there is thin and very unstable. The predominant soils of the steppes are chernozems.
Natural plant communities are predominantly represented by perennial, drought- and frost-resistant grasses with a strong root system. These are primarily cereals: feather grass, fescue, wheatgrass, snake grass, tonkonog, bluegrass. In addition to cereals, there are numerous representatives of forbs: astragalus, sage, cloves - and bulbous perennials, such as tulips.
The composition and structure of plant communities change significantly both in the latitudinal and meridional directions.
In the European steppes, the basis is made up of narrow-leaved grasses: feather grass, fescue, bluegrass, fescue, tonkonogo, etc. There are many brightly flowering forbs. In summer, feather grass sways like waves in the sea, and here and there you can see lilac irises. In the drier southern regions, in addition to cereals, wormwood, milkweed, and cinquefoil are common. There are many tulips in spring. Tansy and cereals predominate in the Asian part of the country.
Steppe landscapes are fundamentally different from forest ones, which determines the uniqueness of the animal world of this natural zone. Typical animals in this zone are rodents (the largest group) and ungulates.
Ungulates are adapted to long movements across the vast expanses of the steppes. Due to the thinness of the snow cover, plant food is also available in winter. Important role Bulbs, tubers, and rhizomes play a role in nutrition. For many animals, plants are also the main source of moisture. Typical representatives of ungulates in the steppes are aurochs, antelopes, and tarpans. However, most of these species were exterminated or pushed south as a result of human economic activity. In some areas, saigas, which were widespread in the past, have been preserved.
The most common rodents are the ground squirrel, the vole, the jerboa, etc.
Ferrets, badgers, weasels, and foxes also live in the steppe.
Among the birds typical of the steppes are the bustard, little bustard, gray partridge, steppe eagle, buzzard, and kestrel. However, these birds are now rare.
There are significantly more reptiles than in the forest zone. Among them we will highlight the steppe viper, snake, common grass snake, quick lizard, and copperhead.
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 humans and natural steppe landscapes are preserved only in nature reserves. In addition to the high natural fertility of chernozems, farming is also facilitated by climatic conditions favorable for gardening, the cultivation of heat-loving grains (wheat, corn) and industrial crops (sugar beets, sunflowers). Due to insufficient precipitation and frequent droughts, irrigation systems were built in the steppe zone.
The steppes are a zone of developed livestock farming. Cattle, horses, and poultry are raised here. Conditions for the development of livestock farming are favorable due to the presence of natural pastures, feed grain, waste from processing sunflowers and sugar beets, etc.
In the steppe zone there are developed various industries industries: metallurgy, mechanical engineering, food, chemical, textile.
Semi-deserts and deserts
In the southeast of the Russian Plain and in the Caspian Lowland there are semi-deserts and deserts.
The total solar radiation here reaches 160 kcal/cm2. The climate is characterized by high air temperatures in summer (+22 - +24 °C) and low in winter (-25-30 °C). Because of this, there is a large annual temperature range. The sum of active temperatures is 3600 °C or more. In the semi-desert and desert zones there is a small amount of precipitation: an average of up to 200 mm per year. In this case, the humidification coefficient is 0.1-0.2.
Rivers located in semi-deserts and deserts are fed almost exclusively by spring melting snow. A significant part of them flows into lakes or is lost in the sands.
Typical soils in the semi-desert and desert zones are chestnut. The amount of humus in them decreases in the 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 they are light chestnut ( the humus content 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 is carried into the lower horizons.
Plants in semi-deserts are usually low and drought-resistant. The semi-deserts of the south of the country are characterized by such plant species as tree and gnarled saltwort, camel thorn, and juzgun. At higher elevations, 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 wormwood.
To live in conditions of lack of moisture and soil salinity, 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 and 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 during a favorable time of year - spring.
The fauna of semi-deserts and deserts is poor compared to the forest zone. The most common reptiles are lizards, snakes, and 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 and saiga; there are corsac dogs and wolves.
A special area in the semi-desert and desert zone of Russia is the Volga delta and the Akhtuba floodplain. It can be called green oasis in the middle of the semi-desert. This territory is distinguished by its thickets of 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 a lot of algae and white water lilies (including the Caspian rose and water chestnut preserved from the pre-glacial period). Among these plants there are many birds, including herons, pelicans and even flamingos.
The traditional occupation of the population in the semi-desert and desert zones is cattle breeding: sheep, camels, and cattle are raised. As a result of overgrazing, the area of unconsolidated dispersed sand increases. One of the measures to combat the onset of the desert is phytomelioration - a set of measures for cultivating and maintaining natural vegetation. To secure dunes, plant species such as giant grass, Siberian wheatgrass, and saxaul can be used.
Tundra
Vast areas of the coast of the Arctic Ocean from the Kola Peninsula to the Chukotka Peninsula are occupied tundra. The southern border of its distribution is almost
falls e July isotherm 10 °C. Farthest north southern border the tundra moved to Siberia - north of 72° N. latitude. In the Far East, the influence of cold seas has led to the fact that the tundra border reaches almost the latitude of St. Petersburg.
The tundra receives more heat than the polar desert zone. Total solar radiation is 70-80 kcal/cm2 per year. However, the climate here continues to be characterized by low air temperatures, short summers, harsh winter. The average air temperature in January reaches -36 °C (in Siberia). Winter lasts 8-9 months. At this time of year, southern winds blowing from the mainland dominate here. Summer is characterized by an abundance of sunshine and unstable weather: strong northern winds often blow, bringing cold temperatures and precipitation (especially in the second half of summer there are often heavy drizzles). The sum of active temperatures is only 400-500 °C. The average annual precipitation reaches 400 mm. Snow cover lasts 200-270 days a year.
The predominant soil types in this zone are peat-bog and slightly podzolic. Due to the spread of permafrost, which has water-resistant properties, there are many swamps here.
Since the tundra zone has a significant extent from north to south, climatic conditions within its boundaries change noticeably: from severe in the north to more moderate in the south. In accordance with this, arctic, northern, also known as typical, and southern tundras are distinguished.
Arctic tundra occupy mainly the Arctic islands. The vegetation is dominated by mosses, lichens, and flowering plants, which are more numerous than in Arctic deserts. Flowering plants represented by shrubs and perennial herbs. Polar and creeping willow, dryad (partridge grass) are widespread. Of the perennial grasses, the most common are polar poppy, small sedges, some grasses, and saxifrage.
Northern tundra distributed mainly on the mainland coast. Their important difference from the Arctic is the presence of closed vegetation cover. Mosses and lichens cover 90% of the soil surface. Green mosses and bushy lichens predominate, and moss is often found. Species composition flowering plants are also becoming more diverse. There are saxifrage, saxifrage, and viviparous knotweed. Shrubs include lingonberry, blueberry, wild rosemary, crowberry, as well as dwarf birch (ernik) and willows.
IN southern tundras, 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. Middle - 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. Thus, plants with creeping and creeping shoots and leaves collected in a rosette better “use” the 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 summer time. For example, cranberries, birchberries, and crowberries “fight” to retain moisture by “reducing” the size of the leaves as much as possible, thereby reducing the evaporating surface. In dryad and 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. Some species are characterized by the so-called viviparity, when instead of fruits and seeds, the plant develops bulbs and nodules that quickly take root, which provides a “gain” in time.
Animals and birds that constantly live in the tundra have also adapted well to 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. This helps with camouflage.
Typical animals of the tundra are the Arctic fox, lemming, mountain hare, reindeer, white polar and tundra partridge, and polar owl. In summer, the abundance of food (fish, berries, insects) attracts birds such as waders, ducks, geese, etc. to this natural area.
There's enough in the tundra low density population. The indigenous peoples here are the Sami, Nenets, Yakuts, Chukchi, etc. They are mainly engaged in reindeer herding. Mining of minerals is actively carried out: apatites, nephelines, non-ferrous metal ores, gold, etc.
Railroad communication in the tundra is poorly developed; road construction is an obstacle permafrost.
Forest-tundra
Forest-tundra- transitional zone from tundra to taiga. It is characterized by alternating areas occupied by forest and tundra vegetation.
The forest-tundra climate is close to the tundra climate. The main difference: the summer here is warmer - the average July temperature is + 11 (+14) ° C - and long, but the winter is colder: the influence of the winds blowing from the mainland is felt.
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 swampy soil prevent plants from having deep roots, and strong winds bend them to the ground.
In the forest-tundra of the European part of Russia, spruce predominates, pine is less common. Larch is common in the Asian part. The 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 for the winter are perfectly adapted to the local conditions. Lemmings, voles, and tundra partridge make long passages in the snow, feeding on the leaves and stems of evergreen tundra plants. With an abundance of food, lemmings even give birth to offspring at this time of year.
By small forest areas and bush thickets along rivers in southern regions animals from the forest zone come in: white hare, brown bear, white partridge. There are wolves, foxes, ermines, and weasels. Small insectivorous birds fly in.
Subtropics
This zone, occupying the Black Sea coast of the Caucasus, is characterized by the smallest length and area in Russia.
The amount of total solar radiation reaches 130 kcal/cm2 per year. Summer is long, winter is warm (average temperature in January 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 mountain slopes 1000 mm or more of precipitation falls per year. In flat areas, snow cover practically does not form.
Fertile red earth and yellow earth soils are widespread.
Subtropical vegetation is rich and varied. The flora is represented by evergreen hard-leaved trees and shrubs, including boxwood, laurel, and cherry laurel. Forests of oak, beech, hornbeam, and maple are common. The thickets of trees are intertwined with liana, ivy, and wild grapes. There are bamboo, palm trees, cypress, eucalyptus.
Among the representatives of the animal world, we note chamois, deer, wild boar, bear, pine and stone marten, and Caucasian black grouse.
The abundance of heat and moisture makes it possible to grow subtropical crops such as tea, tangerines, and lemons here. 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. There are numerous tourist centers, holiday homes, and sanatoriums here.
The tropical zone contains rainforests, savannas and woodlands, and deserts.
Largely plowed tropical rain forests(South Florida, Central America, Madagascar, Eastern Australia). They are used, as a rule, for plantations (see atlas map).
The subequatorial belt is represented by forests and savannas.
Subequatorial rain forests located mainly in the Ganges valley, southern part Central Africa, on the northern coast of the Gulf of Guinea, northern South America, Northern Australia and the islands of Oceania. In drier areas they are replaced savannah(Southeast Brazil, Central and East Africa, central areas Northern Australia, Hindustan and Indochina). Typical representatives of the animal world of the subequatorial belt are ruminant artiodactyls, predators, rodents, and termites.
At the equator, the abundance of precipitation and high temperatures determined the presence of a zone here evergreen moist forests(Amazon and Congo basin, on the islands South-East Asia). The natural zone 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, but they have their own characteristics. First of all we're talking about about plants and animals that have adapted to exist in these natural areas.
The natural zone of the subtropics is widely represented on the Mediterranean coast, the southern coast of Crimea, the southeastern United States and other regions of the Earth.
Western Hindustan, Eastern Australia, the Parana Basin in South America and South Africa are areas of more arid tropical savannas and woodlands. The most extensive natural area of the tropical belt - desert(Sahara, Arabian desert, deserts of Central Australia, California, as well as Kalahari, Namib, Atacama). Vast areas of pebble, sand, rocky and salt marsh surfaces are devoid of vegetation. The fauna is small.
The warmth of the sun, clean air and water are the main criteria for life on Earth. Numerous climatic zones have led to the division of the territory of all continents and waters into certain natural zones. Some of them, even separated by huge distances, are very similar, others are unique.
Natural areas of the world: what are they?
This definition should be understood as very large natural complexes (in other words, parts geographical zone Earths) that have similar, homogeneous climatic conditions. The main characteristic of natural areas is animals and vegetable world which inhabits this territory. They are formed as a result of the uneven distribution of moisture and heat on the planet.
Table “Natural areas of the world”
Natural area | Climate zone | Average temperature (winter/summer) |
Antarctic and Arctic deserts | Antarctic, Arctic | 24-70°C /0-32°C |
Tundra and forest-tundra | Subarctic and subantarctic | 8-40°С/+8+16°С |
Moderate | 8-48°С /+8+24°С |
|
Mixed forests | Moderate | 16-8°С /+16+24°С |
Broadleaf forests | Moderate | 8+8°С /+16+24°С |
Steppes and forest-steppes | Subtropical and temperate | 16+8 °С /+16+24°С |
Temperate deserts and semi-deserts | Moderate | 8-24 °С /+20+24 °С |
Hardleaf forests | Subtropical | 8+16 °С/ +20+24 °С |
Tropical deserts and semi-deserts | Tropical | 8+16 °С/ +20+32 °С |
Savannas and woodlands | 20+24°С and above |
|
Variably humid forests | Subequatorial, tropical | 20+24°С and above |
Permanently wet forests | Equatorial | above +24°С |
This characteristic of the natural zones of the world is only for informational purposes, because you can talk about each of them for a very long time, and all the information will not fit into the framework of one table.
Natural zones of the temperate climate zone
1. Taiga. It surpasses all other natural zones of the world in terms of land area (27% of the territory of all forests on the planet). It is characterized by very low winter temperatures. Deciduous trees cannot withstand them, so the taiga is dense coniferous forests (mainly pine, spruce, fir, larch). Very large areas Taigas in Canada and Russia are occupied by permafrost.
2. Mixed forests. Characteristic in to a greater extent For Northern Hemisphere Earth. It is a kind of border between taiga and deciduous forest. They are more resistant to cold and long winters. Tree species: oak, maple, poplar, linden, as well as rowan, alder, birch, pine, spruce. As the table “Natural Zones of the World” shows, the soils in the mixed forest zone are gray and not highly fertile, but are still suitable for growing plants.
3. Broad-leaved forests. They are not adapted to harsh winters and are deciduous. Occupy most Western Europe, south Far East, northern China and Japan. Suitable for them is maritime climate or temperate continental with hot summers and fairly warm winters. As the table “Natural zones of the world” shows, the temperature in them does not fall below -8°C even in the cold season. The soil is fertile, rich in humus. Characteristic the following types trees: ash, chestnut, oak, hornbeam, beech, maple, elm. The forests are very rich in mammals (ungulates, rodents, predators), birds, including game birds.
4. Temperate deserts and semi-deserts. Their main distinctive feature- practically complete absence vegetation and sparse fauna. There are quite a lot of natural areas of this nature; they are located mainly in the tropics. There are temperate deserts in Eurasia, and they are characterized by sharp changes in temperature across the seasons. Animals are represented mainly by reptiles.
Arctic deserts and semi-deserts
They are huge areas of land covered with snow and ice. A map of the world’s natural zones clearly shows that they are located in North America, Antarctica, Greenland and the northern tip of the Eurasian continent. In fact, these are lifeless places, and only along the coast are polar bears, walruses and seals, arctic foxes and lemmings, and penguins (in Antarctica). Where the ground is free of ice, lichens and mosses can be seen.
Equatorial rainforests
Their second name is rain forests. They are located mainly in South America, as well as in Africa, Australia and the Greater Sunda Islands. The main condition for their formation is constant and very high humidity (more than 2000 mm of precipitation per year) and a hot climate (20°C and above). They are very rich in vegetation, the forest consists of several tiers and is an impenetrable, dense jungle, which has become home to more than 2/3 of all types of creatures now living on our planet. These rain forests are superior to all other natural areas in the world. The trees remain evergreen, changing foliage gradually and partially. Surprisingly, the soils of humid forests contain little humus.
Natural zones of the equatorial and subtropical climate zone
1. Variably humid forests, they differ from rain forests in that precipitation falls there only during the rainy season, and during the period of drought that follows, the trees are forced to shed their leaves. The flora and fauna are also very diverse and rich in species.
2. Savannas and woodlands. They appear where moisture, as a rule, is no longer sufficient for the growth of variable-humid forests. Their development occurs in the interior of the continent, where tropical and equatorial air masses dominate, and the rainy season lasts less than six months. They occupy a significant part of the territory of subequatorial Africa, hinterland South America, partly Hindustan and Australia. More detailed information about the location is reflected in the map of natural areas of the world (photo).
Hardleaf forests
This climate zone is considered the most suitable for human habitation. Hard-leaved and evergreen forests are located along sea and ocean coasts. Precipitation is not so abundant, but the leaves retain moisture due to their dense leathery shell (oaks, eucalyptus), which prevents them from falling. In some trees and plants they are modernized into spines.
Steppes and forest-steppes
They are characterized by an almost complete absence of woody vegetation, due to the poor level of precipitation. But the soils are the most fertile (chernozems), and therefore are actively used by humans for farming. The steppes occupy large areas in North America and Eurasia. The predominant number of inhabitants are reptiles, rodents and birds. Plants have adapted to the lack of moisture and most often manage to complete their life cycle during the short spring period, when the steppe is covered with a thick carpet of greenery.
Tundra and forest-tundra
In this zone the breath of the Arctic and Antarctic begins to be felt, the climate becomes more severe, and even coniferous trees cannot withstand it. There is an abundance of moisture, but there is no heat, which leads to swamping of very large areas. There are no trees at all in the tundra; the flora is mainly represented by mosses and lichens. It is considered to be the most unstable and fragile ecosystem. Due to the active development of gas and oil fields it is on the verge of an environmental disaster.
All natural areas of the world are very interesting, be it the seemingly absolutely lifeless desert, the endless arctic ice or thousand-year-old rain forests with boiling life inside.
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 “continent” and “ocean” were formed. But the nature of each continent, like each ocean, is not the same. Their territories contain various natural zones.
A natural zone is a large natural complex that has common temperature and moisture conditions, soils, vegetation and fauna. The formation of zones is determined by climate, on land - by 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 temperatures are high and there is little precipitation, then a tropical desert zone is formed.
Natural land areas differ in appearance from each other in the nature of their vegetation. The vegetation of the zones, of all the components of nature, most clearly expresses all the most important features of their nature, the relationship between the components. If changes occur in individual components, then externally this affects primarily the change in vegetation. Natural land areas are named according to the nature of their vegetation, for example desert zones, equatorial forests, etc.
The World Ocean also has natural zones (natural zones). They differ in water masses, organic world, etc. Natural zones of the ocean do not have clear external differences, with the exception of ice cover, and are named by their geographical location, like climatic zones.
Scientists have discovered a clear pattern in the distribution of natural zones on the earth’s surface, which can be clearly seen on the map of natural zones. To understand this pattern, let us trace on the map the change in natural zones from north to south along 20° east. e. In the subarctic zone, where temperatures are low, there is a zone of tundra and forest-tundra, giving way to taiga to the south. There is enough heat and moisture here 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 deciduous forests. Somewhat to the east, the amount of precipitation decreases, so the steppe zone is located here. The Mediterranean coastline in Europe and Africa is dominated by a Mediterranean climate with dry summers. It favors the formation of a zone of hard-leaved evergreen forests and shrubs. Next we find ourselves in the tropical zone. Here, in the sun-scorched expanses, it is scorching, the vegetation is sparse and stunted, and in some places completely absent. This is a tropical desert area. To the south it gives way to savannas - tropical forest-steppes, where there is already a wet season and a lot of heat. But the amount of precipitation is not enough for forest growth. In the equatorial climate zone there is a lot of heat and moisture, so a zone of humid equatorial forests with very rich vegetation is formed. In South Africa, zones, like climate 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 are apparently convinced that the alternation of natural zones on the plains is explained by changing climatic conditions - geographic 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 trace on the map 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 marine air masses coming from the ocean dominate, there is a zone of deciduous forests, beech, oak, linden, etc. grow. When moving to the east, the forest zone gives way to a zone of forest-steppes and steppes. The reason is a decrease in precipitation. Even further to the east, precipitation becomes less and the steppes turn into deserts and semi-deserts, which further to the east again give way to steppes, and near the Pacific Ocean - to a 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 for the same reasons - a change in the ratio of heat and moisture, which is determined by the proximity or distance to 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, and currents.
The location of natural zones is closely related to climatic zones. Like climate zones, they naturally replace each other from the equator to the poles due to a decrease in solar heat reaching the Earth's surface and uneven moisture. This change of natural zones - large natural complexes is called latitudinal zoning. Zoning is manifested in all natural complexes, regardless of their size, as well as in all components of the geographical envelope. Zoning is a basic geographical pattern.
A change in 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 altitude the amount of precipitation increases, and lighting conditions change. Due to changing climatic conditions, natural zones are also changing. The successive zones seem to encircle mountains at different altitudes, which is why they are called altitudinal zones. The change in altitudinal zones in the mountains occurs much faster than the change in zones on the plains. It is enough to climb 1 km to see 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 peak you will find the following altitude zones: taiga, mountain tundra, eternal snow. If you have to climb the Andes near the equator, then you will begin your journey from the belt (zone) of equatorial forests. The pattern is this: the higher the mountains and the closer they are to the equator, the more altitude zones there are and the more diverse they are. In contrast to zonality on the plains, the alternation of natural zones in the mountains is called altitudinal zonation or altitudinal zonation.
The law of geographic zoning also manifests itself in mountainous areas. We have already considered some of them. Also, the change of day and night and seasonal changes depend on geographic latitude. If the mountain is located 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.