Geographic zoning is a general characteristic. Geographical zoning
The doctrine of geographical zoning. A region in a broad sense, as already noted, is a complex territorial complex, which is delimited by specific homogeneity various conditions, including natural and geographical ones. This means that there is regional differentiation of nature. The processes of spatial differentiation of the natural environment are greatly influenced by such phenomena as zonality and azonality of the geographical shell of the Earth. By modern ideas, geographic zonality means a natural change in physical-geographical processes, complexes, and components as one moves from the equator to the poles. That is, zonation on land is a consistent change of geographical zones from the equator to the poles and the regular distribution of natural zones within these zones (equatorial, subequatorial, tropical, subtropical, temperate, subarctic and subantarctic).
In recent years, with the humanization and sociologization of geography geographical zones are increasingly being referred to as natural-anthropogenic geographical zones.
The doctrine of geographical zoning has great importance for regional and regional studies analysis. First of all, it allows us to reveal the natural prerequisites for specialization and farming. And in the conditions of modern scientific and technological revolution, with a partial weakening of the economy’s dependence on natural conditions and natural resources, its close ties with nature, and in many cases dependence on it, continue to be maintained. Obvious and persistent important role natural component in the development and functioning of society, its territorial organization. Differences in the spiritual culture of the population also cannot be understood without referring to natural regionalization. It also forms the skills of a person’s adaptation to the territory and determines the nature of environmental management.
Geographic zoning actively influences regional differences in the life of society, being an important factor in zoning, and, consequently, regional policy.
The doctrine of geographic zonality provides enormous material for country and regional comparisons and thereby contributes to the elucidation of country and regional specifics and its causes, which ultimately is the main task of regional studies and regional studies. For example, the taiga zone in the form of a trail crosses the territories of Russia, Canada, and Fennoscandia. But the degree of population, economic development, and living conditions in the taiga zones of the countries listed above have significant differences. In regional studies and country studies analysis, neither the question of the nature of these differences nor the question of their sources can be ignored.
In a word, the task of regional and regional studies analysis is not only to characterize the features of the natural component of a particular territory ( theoretical basis This is what constitutes the doctrine of geographic zonality), but also the identification of the nature of the relationship between natural regionalism and the regionalization of the world according to economic, geopolitical, cultural-civilizational, etc. reasons.
Loop method
Loop method. The basic basis of this method is the fact that almost all space-time structures are characterized by cyclicity. The cycle method is one of the new ones and therefore, as a rule, is personalized, that is, it bears the names of its creators. This method has undoubted positive potential for regional studies. Identified N.N. Kolosovsky energy production cycles, unfolding on certain territories, made it possible to trace the regional specifics of their interaction. And it, in turn, was projected onto certain management decisions, i.e. on regional policy.
The concept of ethnogenesis L.N. Gumilyov, also based on the method of cycles, allows us to penetrate deeper into the essence of regional ethnic processes.
The concept of large cycles, or “long waves” N.D. Kond-Ratiev is not only a tool for analyzing the current state of the world economy, but also has a great predictive charge not only in relation to the development of the world economy as a whole, but also its regional subsystems.
Models of cyclical geopolitical development (I. Wallerstein, P. Taylor, W. Thompson, J. Modelski, etc.) explore the process of transition from one “world order” to another, changes in the balance of power between great powers, the emergence of new conflict zones, centers of power . Thus, all these models are important when studying the processes of political regionalization of the world.
20. Program-target method. This method is a way to study regional systems, their socio-economic components and at the same time an important tool for regional policy. Examples of target comprehensive programs in Russia are presidential program"Economic and social development Far East and Transbaikalia for 1996–2005”, “Federal program for the development of the Lower Angara region”, adopted in 1999, etc.
The program-target method is aimed at solving complex problems and is associated with the development of long-term forecasts for the socio-economic development of the country and its regions.
The program-target method is actively used to solve regional policy problems in most countries of the world. In Italy, as part of regional policy, the first law on “growth poles” was adopted in 1957. In accordance with it, several large enterprises were built in the south of Italy (a region that lags far behind the industrialized North), for example, a metallurgical plant in Tarante. “Growth poles” are also being created in France and Spain. The core of Japan's regional programs is the goal of developing infrastructure associated with increasing exports.
Development and implementation of targeted programs – characteristic politicians European Union. Examples of these are, for example, the Lingua and Erasmus programs. The goal of the first of them is to eliminate the language barrier, the second is to expand student exchange between the countries of the Union. In 1994–1999 Within the EU, 13 target programs were financed - “Leader II” (social development of rural areas), “Urban” (elimination of urban slums), “Reshar II” (coal industry), etc.
Related information.
Geographical envelope- this is an integral, continuous shell of the Earth, the environment of human activity, within which the lower layers of the atmosphere, the upper layers of the lithosphere, the entire hydrosphere and the biosphere come into contact, mutually penetrate each other and interact with each other (Fig. 1). All spheres of the geographic envelope continuously exchange matter and energy with each other, forming an integral and balanced natural system.
The geographical envelope does not have clear boundaries, so scientists draw them in different ways. The upper boundary is combined with the boundary of the troposphere (8-18 km) or with the ozone screen (25-30 km). The lower boundary is taken to be the boundary of the earth's crust (from 5 km under the oceans to 70 km under the mountainous structures of the continents) or the lower boundary of its sedimentary layer (up to 5 km). Matter in the geographic envelope is in three states: solid, liquid, gaseous. This is of great importance for the development of life and events. natural processes on the ground.
The main sources of development of all processes occurring in the geographic shell are solar energy and the internal energy of the Earth. Experiencing the geographical envelope and the influence of space. Only in it are conditions created for the development of organic life.
Basic patterns of the geographical envelope
The geographical shell is characterized by the following general patterns of its development: integrity, rhythm, circulation of substances and energy, zonality, azonality. Knowledge of the general patterns of development of the geographical shell allows a person to use more carefully natural resources without causing damage to the environment.
Integrity- this is the unity of the geographical envelope, the interconnection and interdependence of its natural components (rocks, water, air, soils, plants, animals). The interaction and interpenetration of all natural components of the geographical envelope connects them into a single whole. Thanks to these processes, natural balance is maintained. A change in one component of nature inevitably entails a change in other components and the geographic environment as a whole. Knowledge of the law of integrity of the geographical envelope is of great importance practical significance. If human economic activity does not take into account this pattern of the geographical shell, then destructive processes will occur in it.
A preliminary thorough study of the area that is exposed to human impact is required. For example, after draining a swamp, the groundwater level decreases. As a result, the soil, microclimate, vegetation, animal world, i.e. the natural balance of the territory is disrupted.
Understanding the integrity of the geographical envelope allows us to anticipate possible changes in nature and give a geographical forecast of the results of human impact on nature.
Rhythm- this is the repeatability of certain natural phenomena at certain time intervals, or rhythms. In nature, all processes and phenomena are subject to rhythms. There are rhythms of different durations: daily (change of day and night), annual (change of seasons), intracentury (associated with changes in solar activity - 11, 22 years, etc.), centuries-old (centennial) and covering millennia and many millions of years. Their duration can reach 150-240 million years. Associated with them, for example, are periods of active formation of mountains and relative calm of the earth's crust, cooling and warming of the climate.
The most famous is the 11-year rhythm of solar activity, which is determined by the number of spots visible on the surface of the Sun. An increase in solar activity is accompanied by an increase in the number of sunspots and the flow of solar energy to the Earth (“solar wind”). It's causing on earth magnetic storms, affects weather and climate, human health.
Cycle of matter and energy- the most important mechanism for the development of natural processes of the geographical shell, thanks to which the exchange of substances and energy occurs between its component parts. There are various circulations (cycles) of substances and energy: the water cycle (hydrological cycle), air circulation in the atmosphere (atmospheric circulation), circulation in the lithosphere (geological cycle), etc.
The circulation of substances also occurs in the lithosphere. Magma flows to the surface and forms igneous rocks. Under the influence of solar energy, water and temperatures, they are destroyed and turned into sedimentary rocks. Submerging to great depths, sedimentary rocks experience high temperatures and pressure and transform into metamorphic rocks. At very high temperatures, rocks melt and they return to their original state (magma).
The cycles are not closed, they are constantly under the influence of external and internal forces, they occur qualitative changes substances and energy, the development of all components of nature and the geographical envelope as a whole. This helps maintain balance in nature and restore it. For example, with slight contamination, water can purify itself.
The main regularity of the geographic envelope is the manifestation of geographic zonality. Geographical zoning- the basic law of the distribution of natural complexes on the Earth’s surface, which manifests itself in the form of latitudinal zoning (consecutive change of geographical zones and natural zones). Latitudinal zonation- a natural change in natural conditions on the Earth’s surface from the equator to the poles, associated with a change in the angle of incidence sun rays. A single and integral geographical envelope is heterogeneous at different latitudes. Due to uneven distribution solar heat With latitude on the globe, not only climate, but also soil-forming processes, vegetation, fauna, and the hydrological regime of rivers and lakes naturally change from the equator to the poles.
The largest zonal divisions of the geographical envelope are geographical zones. They, as a rule, extend in the latitudinal direction, replacing each other on land and in the ocean from the equator to the poles and are repeated in both hemispheres: equatorial, subequatorial, tropical, subtropical, temperate, subarctic and subantarctic, arctic and antarctic. Geographical zones differ from each other in air masses, climate, soils, vegetation, and wildlife.
Each geographical zone has its own set of natural zones. Natural area- a zonal natural complex within a geographic zone, which is characterized by common temperature conditions, moisture, similar soils, flora and fauna.
According to the change climatic conditions From south to north, in latitude, natural zones also change. The change in natural zones with geographic latitude is a manifestation geographical law latitudinal zonality. Climatic conditions, especially humidity and temperature amplitudes, also change with distance from the ocean into the interior of the continents. Therefore, the main reason for the formation of several natural zones within a geographical zone is the relationship between heat and moisture. (Use the atlas map to analyze the correspondence of natural zones to geographical zones.)
Each natural zone is characterized by a certain climate, type of soil, vegetation and fauna. Natural zones naturally change from the equator to the poles and from the ocean coasts to the interior of the continents following changes in climatic conditions. The nature of the relief affects the moisture regime within the natural zone and can disrupt its latitudinal extent.
Along with zonality, the most important regularity of the geographical envelope is azonality. Azonality- is the formation of natural complexes associated with the manifestation internal processes Lands that determine the heterogeneity of the earth's surface (the presence of continents and oceans, mountains and plains on continents, etc.). Azonality is most clearly manifested in the mountains in the form of altitudinal zonality. Altitudinal zone- natural change of natural complexes (belts) from the foot of the mountains to their peaks (see Fig. 2). Altitudinal zonation has much in common with latitudinal zonality: the change of zones when ascending the mountains occurs in approximately the same sequence as on the plains when moving from the equator to the poles. The first altitudinal zone always corresponds to the natural zone in which the mountains are located.
The main patterns of the geographical shell are integrity, rhythm, circulation of substances and energy, zonality, azonality. Knowledge about the patterns of development of the geographical envelope is necessary for understanding the processes and phenomena occurring in nature, and anticipating the consequences of human economic activity.
As a result of studying the material in this chapter, the student should:
- know definition of the law of geographical zoning; names and location of geographical zones of Russia;
- be able to characterize each geographical zone on the territory of Russia; explain the specifics of the configuration of geographical zones of Russia;
- own the idea of zonality as a natural and cultural phenomenon.
Geographical zoning as a natural and cultural phenomenon
Medieval travelers, crossing large spaces and observing landscapes, already noted the natural, not random nature of changes in nature and culture in space. Thus, the famous Arab geographer Al-Idrisi compiled a map of the Earth, where he showed seven climatic latitudinal zones in the form of stripes - from the equatorial strip to the northern snowy desert zone.
Naturalists second half of the 19th century V. tried to explain the phenomenon of geographic zoning from a systemic perspective.
Firstly, they found that the main reason for the occurrence of this phenomenon is the spherical shape of the Earth, which is associated with the uneven supply of heat at different geographical latitudes. Based on field research carried out mainly on the Russian Plain, the outstanding Russian scientist V.V. Dokuchaev (he has the honor of discovering the law of geographic zonation) showed that not only climate, but also other elements of nature (natural waters, soils, vegetation, animals) world) are distributed over the earth's surface in a certain pattern. The scientist noted that “thanks to the known position of our planet relative to the Sun, thanks to the rotation of the Earth, its spherical shape, climate, vegetation and animals are distributed over the earth’s surface in the direction from north to south, in a strictly defined order, with a regularity that allows the division of the globe into belts - polar, temperate, subtropical, equatorial, etc.” .
Secondly, scientists explained why geographic zones do not always have a latitudinal extension: if there were no oceans on the Earth and its entire surface was flat, then the zones would encircle the entire Earth in the form of parallel stripes. But the presence, on the one hand, of oceans, and on the other, of irregularities (mountains, hills) distorts the ideal picture. Geographical zoning is better expressed on the plains in the form of certain stripes, belts or zones It is no coincidence that the landscapes of watershed plains and lowlands are called zonal. TO azonal include those landscapes that differ sharply from typical zonal landscapes. Let us recall, for example, the landscapes of the Nile River Valley, which are completely different from the zonal landscapes of the surrounding tropical deserts. The most common azonal landscapes are landscapes of river valleys and mountain landscapes.
However, the most important discovery made by V.V. Dokuchaev is that geographical zonation represents natural and cultural phenomenon. It affects not only nature, but also culture and human activity. According to Dokuchaev, a person is zoned in all manifestations of his life:“in customs, religion (especially in non-Christian religions), in beauty, even sexual activity, in clothing, in all everyday situations; zonal - livestock... cultivated vegetation, buildings, food and drink. Anyone... who had to travel from Arkhangelsk to Tiflis could easily see how much the buildings, dress, morals, customs of the population and their beauty change depending on the climate, animals, plants, soil characteristic of a particular area.”
Under geographical area V.V. Dokuchaev understood a system in which nature (climate, water, vegetation, fauna) and man and his activities are interconnected, “tuned” to each other.
It is obvious that the relationship between human communities and the surrounding landscapes was closer before the industrial revolution, when man's technical capabilities were more modest, he lived closer to nature, and there were significantly fewer people. Nevertheless, every people, even the most “technical”, retains the memory of the “mother” (well-defined zonal or azonal) landscape, forest or wall, of the images of the Motherland associated with this landscape, not only visual, but also cultural and linguistic . Language preserves the memory of the developed landscapes and contains their characteristics.
Currently, the fact of zonal differentiation of the natural environment is obvious. V.V. Dokuchaev is credited with establishing the law of geographic zoning (1899), which was confirmed by numerous studies (Berg, 1930, 1947; Grigoriev, 1954, 1966; Isachenko, 1965, 1980; Gvozdetsky, 1976, 1979; Milkov, 1970, and DR-) Under the term "zoning" is understood as “a regular change in all geographical components and landscapes along latitude (from the equator to the poles) - the most well-known geographical pattern.
Primary The reason for zonality is the uneven distribution of solar radiation across latitude due to the spherical shape of the Earth. The angle of incidence of solar rays naturally changes in the latitudinal direction, due to which the amount of solar energy arriving per unit of the earth's surface changes in the same direction. Thus, the presence of zonality on Earth is entirely due to planetary-cosmic, or astronomical, reasons.
However, planetary-cosmic reasons create only the basic prerequisites for the emergence of zonality” (Isachenko, 1965, pp. 48-49). The decisive importance of solar radiation in the formation of geographical zones was also recognized by S. V. Kalesnik: “Due to the zonal distribution of solar radiant energy on Earth, the following are zonal: air, water and soil temperature, evaporation and cloudiness, precipitation, baric relief and wind systems, properties of air masses, climates, the nature of the hydrographic network and hydrological processes, features of geochemical processes, weathering and soil formation, types of vegetation and life forms of plants and animals, sculptural landforms, to a certain extent types of sedimentary rocks, finally, geographical landscapes, united in this regard into a system of landscape zones" (Kalesnik, 1970, pp. 91-92). However, V.V. Dokuchaev drew attention to the fact that not only direct solar radiation, but and such important climate elements as advective warmth and moisture. He even established that each natural zone is characterized not only by a certain amount of heat and annual amount atmospheric precipitation, but also a certain relationship between them (Fig. 90-101). Later, A. A. Grigoriev and M. I. Budyko paid much attention to this issue (1956, 1974, etc.). Considering. the problem of geographic zoning, A. A. Grigoriev states: “Changes in the structure and development of the geographical environment (land) across belts, zones and subzones are based primarily on changes in the amount of heat, as the most important energy factor, the amount of moisture, the ratio of the amount of heat and the amount of moisture "(Grigoriev, 1954, p. 18) (Fig. 102). M. I. Budyko adheres to the same view on zoning. It can be concluded that the main factor in the formation of geographical zones is climate. To what extent this conclusion is true, we will try to confirm this with two examples:
1) natural zonality of the planet Venus and 2) paleozonality of the Earth.1. On Vner there are no natural zones at all, although more heat is supplied than to the ground. The absence of natural zonality on Venus is due to the atmosphere, i.e., the climatic factor. Conditions 2.
The phenomenon of paleozonality on planet Earth is used here to prove the relative independence of the geographical envelope from the tectonosphere, the boundary between which is formed by a horizon of constant temperature in earth's crust(Lyubimova, 1968). The evolution of the tectonosphere, and accordingly the macrorelief of the earth's surface, proceeds extremely slowly. To restructure the tectonosphere and large forms relief takes millions of years. Modern mountain ranges are of this age. The main elements of the geographical envelope - geographical zones - can be formed over thousands of years, that is, in a time 1 thousand times less than it takes for the formation or complete destruction of a mountain range or its large parts. Therefore, if we analyze the structure of any large uplift (ridge or individual hill), then in a vertical section we must distinguish two parts: the upper, that is, the weathering crust, and the lower, the tectonosphere. The thickness of the upper part of the section is meters, the lower part is hundreds of kilometers. With a strong and long-term climate change (for example, from warm to cold), a restructuring of the zonal structure of the geographical shell and, in particular, its mineral substrate - the weathering crust - will occur. Geographical (landscape) zones will seem to move along the earth's surface, while macroforms of relief and the corresponding tectonic structures will remain motionless. This allows us to conclude that the geographic envelope does not have “deep roots” in the lithosphere. The above fully applies to vertical (high-altitude) zones.
High-altitude zones occupy smaller spaces than plain (latitudinal) zones, and seem to repeat them: mountain glaciers - the polar zone, mountain tundra - tundra, mountain forests - forest zone, etc. The lower part of the mountains usually merges with the latitudinal zone, within which they are located. So, for example, the taiga approaches the foothills of the Northern and Middle Urals, a desert stretches at the foot of some mountains of Central Asia, which lie in the desert zone, and in the Himalayas the lower part of the mountains is covered tropical jungle etc. Largest quantity altitudinal zones (from glaciers at the tops of mountains to tropical forests at the foot) is observed in high mountains located near the equator.
Although high-altitude zones are similar to plain zones, the similarity is very relative.
Indeed, the amount of precipitation in mountains usually increases with altitude, while in the direction from the equator to the poles it generally decreases. In mountains, the length of day and night does not change with altitude as much as when moving from the equator to the poles. In addition, climatic conditions in the mountains become more complex: the steepness of the slopes and their exposure (northern or southern, western or eastern slopes) play a significant role here, special wind systems arise, etc. All this leads to the fact that both soils and the vegetation and fauna of each high-altitude zone acquire special features that distinguish it from the corresponding lowland zone.
The differences in natural zones on land are most clearly reflected by vegetation. Therefore, most zones are named according to the type of vegetation that predominates in them. These are the zones of temperate forests, forest-steppes, steppes, tropical rainforests, etc.
Geographic zones can also be traced in the oceans, but they are less pronounced than on land, and only in the upper layers of water - to a depth of 200-300 m. Geographic zones in the oceans generally coincide with thermal zones, but not completely, since the water is very mobile , sea currents constantly mix it, and in some places transfer it from one zone to another.
In the World Ocean, as on land, there are seven main geographical zones: equatorial, two tropical, two temperate and two cold. They differ from one another in temperature
temperature and salinity of water, the nature of currents, vegetation and fauna (see page 146).
Thus, the waters of cold zones have low temperature. They contain slightly less dissolved salts and more oxygen than the waters of other zones. Vast areas of the seas are covered with thick ice, and the vegetation and fauna are poor in species composition.
In temperate zones, surface layers of water heat up in summer and cool in winter. Ice in these zones appears only in places, and even then only in winter. The organic world is rich and diverse. Tropical and equatorial waters are always warm. Life is abundant in them.
Natural areas
The location of ecological communities on Earth has a pronounced zonal structure associated with changes in thermal conditions (primarily the flow of solar energy) at different latitudes. Natural zones are elongated in the latitudinal direction and replace each other when moving along the meridian. Own, altitudinal, zoning is formed in mountain systems; In the world's oceans, the change in ecological communities with depth is clearly visible. Natural areas are closely related to the concept of habitat - the area of distribution of a given type of organism. Biogeography studies the patterns of distribution of biogeocenoses on the Earth's surface.
The earth's land is divided into 13 main latitude zones: Arctic and Antarctic, subarctic and subantarctic, northern and southern temperate, northern and southern subtropical, northern and southern tropical, northern and southern subequatorial, equatorial.
Let's consider the main biogeographical zones of land. The area around the poles is covered by cold Arctic (in the Southern Hemisphere - Antarctic) deserts. They are characterized by an extremely harsh climate, extensive ice sheets and rocky deserts, undeveloped soils, and the scarcity and monotony of living organisms. Animals arctic deserts associated mainly with the sea - this polar bear, pinnipeds, in Antarctica - penguins.
To the south of the Arctic deserts is the tundra (Finnish tunturi “treeless hill”); in the Southern Hemisphere, tundra is represented only on some subantarctic islands. The cold climate and soils underlain by permafrost determine the predominance of mosses, lichens, herbaceous plants and shrubs here. To the south, small trees (for example, dwarf birch) appear, and the tundra gives way to forest-tundra. The fauna of the tundra is quite homogeneous and scarce: reindeer, arctic foxes, lemmings and voles, as well as extensive bird colonies. Mosquitoes are abundant among insects. Most vertebrates leave the tundra with the onset of winter (migrate or fly away to warmer regions). Near the seas and oceans, tundra and forest-tundra give way to a zone of oceanic meadows.
To the south of the forest-tundra, temperate zone forests begin; first coniferous (taiga), then mixed, and finally broad-leaved (the southern temperate zone almost completely covers the world's oceans). temperate forests occupy vast territories in Eurasia and North America. The climate here is already much warmer, and the species diversity is several times greater than in the tundra. On podzolic soils, large trees dominate - pine, spruce, cedar, larch, and to the south - oak, beech, birch. The most common animals are carnivores (wolf, fox, bear, lynx), ungulates (deer, wild boars), songbirds, and certain groups of insects.
The temperate forest zone is replaced by forest-steppe and then steppe. The climate is becoming warmer and drier, among soils greatest distribution chernozems and chestnut soils are obtained. Cereals predominate, among animals there are rodents, predators (wolf, fox, weasel), birds of prey (eagle, hawk), reptiles (vipers, snakes), beetles. A large percentage of the steppes are occupied by agricultural land. Steppes are common in the Midwest of the United States, Ukraine, the Volga region and Kazakhstan.
The next zone after the steppe is the zone of temperate semi-deserts and deserts (Middle and central Asia, West Side North America, Argentina). The desert climate is characterized by low precipitation and large daily temperature fluctuations. As a rule, there are no bodies of water in deserts; Only occasionally the deserts are crossed by large rivers (Huang He, Syrdarya, Amu Darya). The fauna is quite diverse; most species are adapted to living in arid conditions.
As you approach the equator, the temperate zone is replaced by subtropics. In the coastal zone (northern coast of the Mediterranean Sea, southern coast of Crimea, the Middle East, southeastern USA, extreme south of South Africa, southern and western coasts of Australia, North Island of New Zealand) evergreen subtropical forests are common; far from the sea there is forest-steppe (in North America - prairies), steppe and deserts (the latter in South Australia, in south coast Mediterranean Sea, Iran and Tibet, Northern Mexico and western South Africa). The fauna of the subtropics is characterized by a mixture of temperate and tropical species.
Tropical rain forests (South Florida, West Indies, Central America, Madagascar, Eastern Australia) are largely plowed and used for plantations. Large animals have been practically exterminated. Western Hindustan, Eastern Australia, Parana Basin in South America and South Africa– zones of distribution of more arid tropical savannas and woodlands. The most extensive zone of the tropical belt is deserts (Sahara, Arabian Desert, Pakistan, Central Australia, Western California, Kalahari, Namib, Atacama). Vast areas of pebble, sand, rocky and salt marsh surfaces are devoid of vegetation. The fauna is sparse.
Subequatorial rain forests are concentrated in the Ganges Valley, southern Central Africa, the northern coast of the Gulf of Guinea, northern South America, northern Australia and the islands of Oceania. In drier areas they are replaced by savannas (Southeastern Brazil, Central and Eastern Africa, central areas Northern Australia, Hindustan and Indochina). Characteristic representatives of the animal world subequatorial belt– ruminant artiodactyls, predators, rodents, termites.
Closest to the equator is the equatorial belt (Amazon basin, Central Africa, Indonesia). The abundance of precipitation and high temperatures have led to the presence of evergreen moist forests here (in South America such a forest is called hylea). Equatorial belt– record holder for the diversity of animal and plant species.
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| Altitudinal zone |
Similar patterns are observed in the change of biogeographic zones in the mountains - altitudinal zones. It is caused by changes in temperature, pressure and air humidity with increasing altitude. There is, however, no complete identity between the altitudinal, on the one hand, and latitudinal, on the other hand, belts. Thus, the shifts inherent in the typical tundra polar days and the night is deprived of its high-mountain counterparts in lower latitudes, as well as alpine meadows.
The most complex spectra of altitudinal zones are characteristic of the high mountains located near the equator. Toward the poles, the levels of altitudinal belts decrease, and their diversity decreases. The spectrum of altitudinal zones also changes with distance from the seashore.
The same natural areas are found on different continents, but forests and mountains, steppes and deserts have their own characteristics on different continents. Plants and animals that have adapted to exist in these areas also differ. natural areas. In biogeography, there are six biogeographic regions:
Palearctic region (Eurasia without India and Indochina, North Africa);
Nearctic region (North America and Greenland);
Eastern region(Hindustan and Indochina, Malay Archipelago);
Neotropical region (Central and South America);
Ethiopian region (almost all of Africa);
Australian region (Australia and Oceania).
Living organisms inhabit not only land, but also the oceans. The ocean is home to about ten thousand species of plants and hundreds of thousands of animal species (including more than 15 thousand species of vertebrates). Plants and animals inhabit two very different regions of the world's oceans - the pelagic (surface layers of water) and the benthic (sea floor). Latitudinal zones are well expressed only in the near-surface waters of the ocean; With increasing depth, the influence of the sun and climate decreases, and the water temperature approaches +4 °C typical for the ocean thickness.
The pelagic zone - the water column of oceans, seas and lakes - is divided into vertical zones according to illumination (well-lit, twilight and devoid of light) and according to the distribution of life (surface, transitional and deep-sea). Pelagic organisms are characterized by similar adaptations that provide buoyancy. They are divided into passively floating on the surface of the water (pleiston: sargassum algae, siphonophores, etc.) or in its thickness (plankton) and actively floating organisms that can withstand the force of the current (nekton: fish, squid, water snakes and turtles, penguins, cetaceans, pinnipeds, and large crustaceans). Nekton is distinguished by an elongated body shape with the least drag on water when moving.
Plant pelagic organisms (phytoplankton: mainly green algae and diatoms) are the main producers of organic matter in the ocean. Phytoplankton are most common in places where they are carried out from the depths or runoff from land nutrients– phosphates and nitrates. The need for solar energy limits their distribution to a depth of 50–100 m. Zooplankton (crustaceans, protozoa, jellyfish and ctenophores, larvae of various animals) can be found at greater depths. Tropical areas of the oceans, far from land, are the poorest in the number of species. The remains of pelagic organisms participate in the formation of bottom sediments.
The population of the bottom - benthos - is also distributed across deep zones. Among plant organisms, brown, red, diatoms and green algae are common; Flowering plants (reeds, reeds, water lilies, elodea and others) are also found near the shores of freshwater bodies of water. Marine zoobenthos is represented mainly by foraminifera, sponges, coral polyps, polychaete worms, sipunculids, mollusks, crustaceans, bryozoans, echinoderms, ascidians and fish. The inhabitants of shallow waters are especially numerous; their quantity can reach tens of kilograms per 1 m2 of surface. Freshwater zoobenthos is much poorer: mainly protozoa, annelids, mollusks, insect larvae and fish.
This is one of the main laws of the geographical shell of the Earth. It manifests itself in a certain change in natural complexes of geographical zones and all components from the poles to the equator. Zoning is based on the different supply of heat and light to the earth’s surface, depending on geographical latitude. Climatic factors affect all other components and, above all, soils, vegetation, and fauna.
Natural areas. Map.
The largest zonal latitudinal physical-geographical division of the geographical envelope - geographical zone. It is characterized by common (temperature) conditions. The next level of division of the earth's surface is a geographical zone. It is distinguished within the belt not only by the common thermal conditions, but also by moisture, which leads to common vegetation, soils and other biological components of the landscape. Within the zone, subzones are distinguished - transitional areas, which are characterized by mutual penetration of landscapes. They are formed due to gradual changes in climatic conditions. For example, in the northern taiga, tundra areas (forest-tundra) are found in forest communities. Subzones within zones are distinguished by the predominance of landscapes of one type or another. Thus, in the steppe zone two subzones are distinguished: northern steppe on chernozems and southern steppes on dark chestnut soils.
Let's briefly get acquainted with the geographical zones of the globe in the direction from north to south.
Ice zone, or arctic desert zone. Ice and snow remain almost all year round. In the warmest month, August, the air temperature is close to 0 °C. Glacier-free areas are bound by permafrost. Intense frost weathering. Placers of coarse clastic material are common. The soils are underdeveloped, rocky, and of low thickness. Vegetation covers no more than half of the surface. Mosses, lichens, algae and a few species of flowering plants (poppy, buttercup, saxifrage, etc.) grow. Animals include lemmings, arctic fox, and polar bear. In Greenland, northern Canada and Taimyr - musk ox. On rocky coasts bird colonies nest.
Tundra zone of the Earth's subarctic belt. Summer is cold with frosts. Temperature itself warm month(July) in the south of the zone +10 °C, +12 °C, in the north +5 °C. Warm days with average daily temperature It almost never happens above + 15 °C. There is little precipitation - 200–400 mm per year, but due to low evaporation there is excessive moisture. Almost ubiquitous permafrost; high wind speeds. The rivers are full of water in summer. The soils are thin and there are many swamps. The treeless spaces of the tundra are covered with mosses, lichens, grasses, shrubs and low-growing creeping shrubs.
They live in the tundra reindeer, lemmings, arctic foxes, white partridge; in summer there are many migratory birds - geese, ducks, waders, etc. In the tundra zone, moss-lichen, shrub and other subzones are distinguished.
Forest zone of a temperate climate zone with a predominance of coniferous and summer-green deciduous forests. Cold snowy winter And warm summer, excessive moisture; the soil is podzolic and marshy. Meadows and swamps are widely developed. IN modern science The forest zone of the northern hemisphere is divided into three independent zones: taiga, mixed forests and a zone of broad-leaved forests.
The taiga zone is formed by both pure coniferous and mixed species. In the dark coniferous taiga, spruce and fir predominate, in the light coniferous taiga - larch, pine, and cedar. They are mixed with them narrowly deciduous trees, usually birch. The soils are podzolic. Cool and warm summers, harsh, long winters with snow cover. Average July temperatures in the north are +12 °C, in the south of the zone +20 °C, January temperatures range from −10 °C in western Eurasia to −50 °C in Eastern Siberia. Precipitation is 300–600 mm, but this is higher than the evaporation value (except for the south of Yakutia). There is a lot of swampiness. The composition of the forests is uniform: dark coniferous spruce forests predominate on the western and eastern edges of the zone. In areas with sharp continental climate(Siberia) - light larch forests.
The mixed forest zone is coniferous-deciduous forests on soddy-podzolic soils. The climate is warmer and less continental than in the taiga. Winter with snow cover, but without severe frosts. Precipitation 500–700 mm. The Far East has a monsoon climate with annual precipitation up to 1000 mm. The forests of Asia and North America are richer in vegetation than in Europe.
The broad-leaved forest zone is located in the south of the temperate zone along the humid (precipitation 600–1500 mm per year) edges of the continents with their maritime or temperate continental climate. This zone is especially widely represented in Western Europe, where several species of oak, hornbeam, and chestnut grow. The soils are brown forest, gray forest and soddy-podzolic. Such forests grow in their pure form in the Carpathians.
Steppe zones are common in temperate and sub-temperate tropical zones both hemispheres. Currently heavily plowed. IN temperate zone characterized by a continental climate; precipitation - 240–450 mm. Average July temperatures are 21–23 °C. Winter is cold with thin snow cover, strong winds. Predominantly cereal vegetation on chernozem and chestnut soils.
Transitional strips between zones are forest-tundra, forest-steppe and semi-desert. Their territory is dominated, as in the main zones, by its own zonal type of landscape, which is characterized by alternating areas, for example: forest and steppe vegetation - in the forest-steppe zone; open forest with typical tundra - in the lowlands - for the forest-tundra subzone. Other components of nature alternate in the same way - soils, fauna, etc. Significant differences are also noticeable throughout these zones. For example, the Eastern European forest-steppe is oak, the Western Siberian is birch, the Daurian-Mongolian is birch-pine-larch. Forest-steppe is also widespread in Western Europe (Hungary) and North America.
In temperate, subtropical and tropical zones there are desert geographical zones. They are characterized by aridity and continental climate, sparse vegetation and soil salinity. Annual precipitation is less than 200 mm, and in ultra-arid areas it is less than 50 mm. In the formation of the relief of desert zones, the leading role belongs to weathering and wind activity (aeolian landforms).
Desert vegetation consists of drought-resistant subshrubs (wormwood, saxaul) with long roots that allow them to collect moisture from large areas and lush flowering ephemerals in early spring. Ephemera are plants that develop (bloom and bear fruit) in the spring, i.e., in the wettest time of the year. Usually it lasts no more than 5–7 weeks.
Subshrubs are able to tolerate overheating and dehydration, even with water losses of up to 20–60%. Their leaves are small, narrow, sometimes turning into spines; Some plants have pubescent leaves or are covered with a waxy coating, others have succulent stems or leaves (cacti, agaves, aloe). All this helps plants tolerate drought well. Among the animals, rodents and reptiles predominate everywhere.
In subtropical zones, the temperature of the coldest month is at least −4 °C. Humidification varies by season: winter is the wettest. In the western sector of the continents there is a zone of evergreen hard-leaved forests and shrubs of the Mediterranean type. They grow in the northern and southern hemispheres between approximately 30 and 40° latitude. In the inland parts of the northern hemisphere there are deserts, and in the eastern sectors of the continents there are monsoon climate and summer heavy rainfall - deciduous forests (beech, oak) with an admixture of evergreen species, under which yellow soils and red soils are formed.
Tropical zones are located approximately between 20 and 30° N. and Yu. w. Their main features are: arid conditions, high air temperatures on land, anticyclones with the dominance of trade winds, low clouds and light precipitation. Semi-deserts and deserts predominate, they are replaced in the more humid eastern outskirts of the continents by savannas, dry forests and woodlands, and in more favorable conditions, humid tropical forests. The most pronounced savannah zone is a tropical type of vegetation, combining a grassy grass cover with single trees and shrubs. The plants are adapted to withstand prolonged drought: the leaves are hard, heavily pubescent or in the form of thorns, the tree bark is thick.
The trees are low-growing, with gnarled trunks and an umbrella-shaped crown; some trees store moisture in their trunks (baobab, bottle tree, etc.). Animals include large herbivores - elephants, rhinoceroses, giraffes, zebras, antelopes, etc.
Subequatorial belts are characterized by alternating dry and wet periods. Annual precipitation is more than 1000 mm. The division into zones is due to differences in moisture. A zone of seasonally wet deciduous (monsoon) forests, where the wet period lasts up to 200 days, and a zone of savannahs and woodlands with a wet period of up to 100 days. Plants shed their leaves during the dry season, and animals make long journeys in search of water and food.
The equatorial belt is located on both sides of the equator from 5°–8° N. w. to 4°–11° S. w. Constantly high air temperatures (24°–30°C); their amplitude throughout the year does not exceed 4 °C; precipitation falls evenly - 1500–3000 mm per year, in the mountains - up to 10 thousand mm. Seasons of the year are not expressed. Dominated by evergreen moist equatorial forests(hylea, selva), many swamps, podzolized, lateritic soils. Along the seashores there is mangrove vegetation. Most valuable trees- rubber trees, cocoa and breadfruit trees, coconut and other palm trees. The fauna is very diverse. Most of all herbivores live in trees - monkeys, sloths; Birds, insects, and termites are numerous. Dense river network, frequent rises in river water and floods during heavy and prolonged rains.