MASTER CLASS
by geography
7th grade
subject:
"NATURAL ZONING"
Geography teacher
MOU OOSH p. Osanovo-Dubovoe
Ligotskaya S.I.
2010
Target: to study the reasons for the formation of natural zones on Earth, the peculiarity of their location on land and in the Ocean.
Tasks:
1. To form the main patterns and reasons for the formation of natural zones from climate, geological history of the continents, relief, human activity;
2. develop the ability to analyze, compare statistical materials, different types of maps (map of climatic zones and regions of the world and natural zones of the world);
Based on the analysis, draw conclusions, generalizations.
3. to cultivate an ecological outlook when studying the impact of human activity on natural areas and the formation of anthropogenic natural sets.
Equipment:
1) map of climatic zones and regions of the world;
2) map of natural zones of the Earth;
4) exercise book;
5) workbook;
6) an electronic supplement to the textbook.
During the classes.
1. Purpose and objectives of the lesson.
1) Why are natural zones formed inside geographic zones?
2) What influences the distribution and characteristics of natural areas?
2. In order to answer these questions, let's recall the 6th grade material on the topic "Natural complexes" and some data on the topic "Climates of the Earth".
1) What is natural complex? (A stable set of natural components that has developed in a certain area).
2) Give examples of natural complexes, different in size, starting with the largest.
The largest natural complex is the geographic region. Natural complexes of the second order - land and the oceans. The same large natural complexes of individual continents and oceans, on which natural or geographical belts are formed, in them are natural zones, and on the territories of natural zones are small: a swamp, a lake, a ravine, a pine forest, etc.
The diagram is posted:
Geographic
shell
Swamps, lake, ravine, pine forest, etc.
The purpose of our lesson answer the question "Why natural zones are formed within geographic zones."
The geographic zone is (Slide No. 1 - cartoon video). As you can see, the names of geographical zones coincide with what names? (climatic zones).
And what is the reason for the formation of different climatic zones on earth? (The formation of climatic zones depends on geographical latitude, movement of air masses and the nature of the underlying surface).
What climatic factor varies with geographic latitude? (Temperature, which depends on the amount of solar energy entering the Earth's surface). Slide 2 - the flow of solar energy to the surface of the Earth.
Then why don't the boundaries of climatic zones run strictly along parallels? What determines another very important climatic factor, moisture? (for climate big influence air masses, the underlying surface, this is the proximity or remoteness from the ocean, relief, sea currents, ice cover. Therefore, regions are formed inside the climatic zones).
Give examples.
Students on the map of climatic zones show areas of temperate, subtropical, tropical zones.
And the moistening of the territory depends only on the amount of precipitation. For example, 200 mm per year falls in the subarctic climate zone and in the tropical one. But in the subarctic, moisture is excessive, and in the tropics it is scarce. What does it depend on? (On temperature. The higher the temperature, the more moisture evaporates, practically nothing remains in the ground, therefore, in the tropical zone, moisture is scarce, and in the subarctic zone, temperatures are low, little moisture evaporates, so moisture is excessive).
Let's return to the scheme: natural zones are formed within the geographical zones, the names of which coincide with the names of the climatic zones.
Slide number 3 - the definition of " natural area».
Slide number 4 - the names of natural areas and their location.
3.
And now, to answer the question "Why are natural zones formed inside geographic zones?", let's do practical work in workbooks, p.18.
Target: identify the relationship between the location of climates and natural zones of the world based on the analysis of maps of climatic zones and maps of natural zones.
Based on this comparison and analysis, fill in the 2nd table in the workbook. Show the change in climatic zones and natural zones at 20 o E. and 50 about s.sh.
The student shows 20 0 east. and 50 0 s.l. on the cards on the board.
The students do the work on their own. (5 minutes)
Examination: corrected with a red pen.
Now draw a conclusion based on the comparison of these cards.
The conclusion is read out: (Each climatic zone and region has its own natural zone. The reason for their change from N to S and from W to E is a different amount of heat and moisture ratio).
THAT. in the distribution of natural zones on earth's surface there is a certain pattern. Natural zones, like climatic zones, cover our entire planet, ranging from the equator to the poles, but also azonal in temperate, subtropical and tropical zones, their alternation depends on the amount of solar heat and precipitation.
And now, according to the map of natural zones of the world and according to the figure, where statistical data are given, determine which natural zones prevail on each continent.
Answer the questions p.21. and to the questions of the textbook p.35 "My geographical research".
Independent work of students.
Examination. Correction with a red pen.
4. The location of natural areas on the continents are violated by mountains.
Slide - altitudinal zonality.
Performing work on the control sheet:
1) Latitudinal zonality is………………………………………….
2) Altitudinal zoning is………………………………………….
3) Form a pattern: the higher and closer to the equator of the mountain, the ……………….high-altitude belts. The lower and farther from the equator the mountains, the……………………high-altitude zones.
4. In which mountains the number of altitudinal zones is greater:
5. Natural zones are also formed in the World Ocean: from the equator to the poles, the properties of surface waters, the composition of the flora and fauna change.
Slide - natural areas of the ocean.
Slides - the fauna of the equatorial temperate and polar regions of the ocean.
There is also vertical zonality: surface, middle and deep waters.
However, oceanic natural complexes do not have pronounced external differences.
6.
In the same natural areas on different continents, vegetation and fauna have similar features.
Taiga, mixed forest North America and Eurasia are similar. There are similarities in the steppes of North America and Eurasia, the prairies of North America and the pampas of South America.
At the same time, in addition to climate, other factors also influence the peculiarity of the distribution of plants and animals: the geological history of the mainland, the relief and features of rocks, and people.
The unification and separation of the continents, the change in their relief and climate in the geological past, became the reason that in similar natural conditions, but on different continents, live different types plants and animals.
Slide African savannas - characteristic: giraffes, zebras, ostriches, leopards; plants: acacias, oil palms, baobabs, doom palms, cereals, up to 2-3 meters high.
Slide - South American savannas - nandu bird, small deer, baker pigs, armadillos, anteaters; the plant world is poorer: low-growing trees and shrubs studded with thorns, tough grasses, cacti, low acacias, and mimosas are common.
The composition of the organic world of the mainland is strongly influenced by the time of separation of the mainland from the rest of the land.
Thus, the separation of Australia from Gondwana occurred before the appearance of tall mammals on Earth. This led to the flowering of marsupial and egg-laying marsupial mammals in Australia.
Slides - the animal world of Australia.
On each continent there are endemic species peculiar only to this continent.
7. Under the influence of human activity, the geographic envelope and natural areas undergo changes, natural complexes are transformed into natural-anthropogenic and even completely anthropogenic.
Slides are anthropogenic and natural complexes.
What anthropogenic and natural-anthropogenic complexes arose in our area.
We finish the diagram that is placed on the wall:
natural area
But in these places there is a lot of peat, a combustible substance, so fires can easily break out in hot summers.
We all need to be very careful in this regard, not to allow fires to be kindled, not to throw unextinguished cigarettes, as you know that peat fires are very terrible.
It is still possible to solve this problem at the level of the district leadership, for example, watering peat fields, we call them maps, removing locks from ditches that were dug to drain swamps, so swamps will form here again in a few years. Nature will restore itself.
8. To consolidate what we have learned, we will perform test work through multi-video.
9. Analysis of students' answers and their work in the lesson.
10. Homework: Describe the natural area according to the plan:
1) Geographic location.
4) Vegetation.
5) Animal world.
Describing a natural area, reveal the relationships between the components of its nature.
Use maps in the atlas, additional sources, books in the library, the Internet.
The warmth of the sun, clean air and water are the main criteria for life on Earth. Numerous climatic zones led to the division of the territory of all continents and water space into certain natural zones. Some of them, even separated by vast distances, are very similar, others are unique.
Natural areas of the world: what is it?
This definition should be understood as very large natural complexes (in other words, parts of the geographic belt of the Earth), which have similar, uniform climatic conditions. The main characteristic of natural zones is the flora and fauna that inhabits this territory. They are formed as a result of uneven distribution of moisture and heat on the planet.
Table "Natural zones of the world"
natural area | climate zone | Average temperature (winter/summer) |
Antarctic and Arctic deserts | Antarctic, arctic | 24-70°С /0-32°С |
Tundra and forest tundra | Subarctic and Subantarctic | 8-40°С/+8+16°С |
Moderate | 8-48°C /+8+24°C |
|
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 |
hardwood forests | Subtropical | 8+16 °С/ +20+24 °С |
Tropical deserts and semi-deserts | Tropical | 8+16 °С/ +20+32 °С |
Savannahs and woodlands | 20+24°C and above |
|
Variable rainforests | subequatorial, tropical | 20+24°C and above |
Permanently wet forests | Equatorial | above +24°С |
This characteristic of the natural areas of the world is only introductory, because you can talk about each of them for a very long time, all the information will not fit in the framework of one table.
Natural zones of the temperate climate zone
1. Taiga. Surpasses all other natural zones of the world in terms of the area occupied on land (27% of the territory of all forests on the planet). It is characterized by very low winter temperatures. Deciduous trees do not withstand them, so the taiga is dense coniferous forests (mainly pine, spruce, fir, larch). Very large areas of the taiga in Canada and Russia are occupied by permafrost.
2. Mixed forests. Characteristic to a greater extent for the Northern Hemisphere of the Earth. It is a kind of border between the taiga and the broad-leaved forest. They are more resistant to cold and long winters. Tree species: oak, maple, poplar, linden, as well as mountain ash, alder, birch, pine, spruce. As the table "Natural areas of the world" shows, the soils in the zone of mixed forests are gray, not very fertile, but still suitable for growing plants.
3. Broad-leaved forests. They are not adapted to harsh winters and are deciduous. They occupy most of Western Europe, the south of the Far East, the north of China and Japan. Suitable for them is a maritime or temperate continental climate 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. The following types of trees are characteristic: ash, chestnut, oak, hornbeam, beech, maple, elm. The forests are very rich in mammals (ungulates, rodents, predators), birds, including commercial ones.
4. Temperate deserts and semi-deserts. Their main distinguishing feature- almost complete absence of vegetation and poor wildlife. There are 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 temperature changes during the seasons. Animals are represented mainly by reptiles.
Arctic deserts and semi-deserts
They are huge areas of land covered with snow and ice. The map of natural zones of the world clearly shows that they are located on the territory of North America, Antarctica, Greenland and the northern tip of the Eurasian continent. In fact, these are lifeless places, and polar bears, walruses and seals, arctic foxes and lemmings, penguins (in Antarctica) live only along the coast. Where the land is free of ice, lichens and mosses can be seen.
Moist equatorial forests
Their second name is rainforests. 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 a 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 that has become home to more than 2/3 of all types of creatures that now live on our planet. These rainforests are superior to all other natural areas of the world. Trees remain evergreen, changing foliage gradually and partially. Surprisingly, the soils of moist forests contain little humus.
Natural zones of the equatorial and subtropical climatic zone
1. Variably humid forests, they differ from rainforests in that precipitation falls there only during the rainy season, and during the period of drought that follows it, the trees are forced to shed their leaves. The animal and plant world is also very diverse and rich in species.
2. Savannas and woodlands. They appear where moisture, as a rule, is no longer enough for the growth of variable-humid forests. Their development occurs in the depths of the mainland, 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, the interior of South America, partly Hindustan and Australia. More detailed information about the location is reflected in the map of natural areas of the world (photo).
hardwood forests
This climate zone is considered the most suitable for human habitation. Hardwood and evergreen forests are located along sea and ocean coasts. Precipitation is not so abundant, but the leaves retain moisture due to a dense leathery shell (oaks, eucalyptus), which prevents them from falling off. In some trees and plants, they are modernized into thorns.
Steppes and forest-steppes
They are characterized by the almost complete absence of woody vegetation, this is due to the meager level of precipitation. But the soils are the most fertile (chernozems), and therefore are actively used by man for agriculture. 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 in a 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. Moisture is in excess, 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 believed that this is the most unstable and fragile ecosystem. Due to the active development of gas and oil fields, it is on the verge of an ecological disaster.
All the natural areas of the world are very interesting, whether it is a seemingly completely lifeless desert, endless arctic ice or millennia-old rainforests teeming with life.
Under latitudinal zonality(geographical, landscape) understand the regular change in the physical and geographical processes of natural components, as well as the NTC from the equator to the poles. The main reason for zoning is the uneven distribution of the short-wave radiation of the Sun over latitude, due to the sphericity of the Earth. Therefore, two conditions are sufficient for latitudinal zonality:
Uneven distribution of solar radiation
The sphericity of the earth
The latitudinal distribution of solar radiation is not always subject to mathematical calculations. For each of the latitudes, there are also calculations that clearly show a decrease in the number towards the poles. The distribution of solar energy depends on astronomical quantities:
Distance to the sun. The earth is well positioned in relation to the sun.
Earth mass affects the nature of the zoning. The mass of the earth holds the atmosphere with the help of the core, in which there is a lot of metal, and the atmosphere redistributes the radiant energy. The moon is devoid of atmosphere.
The inclination of the earth's axis to the plane of the ecliptic (66.5 o). This angle determines the uneven distribution of solar energy over the seasons, which complicates the zonal distribution of heat and moisture and sharpens zonal contrasts. If earth's axis was perpendicular to the plane of the ecliptic, then each parallel would receive almost the same amount of solar heat throughout the year, and seasonal phenomena would not appear.
Earth's daily rotation causes the deviation of moving bodies, including air masses in the northern hemisphere - to the right, and in the southern hemisphere - to the left (Coriolis force).
The heterogeneous structure of the Earth the presence of continents, large and small islands, oceans, water areas, a variety of rocks (by strength - rocks and loose rocks), a variety of land relief, covering the territory with glaciers, all this causes disturbances in the distribution of solar energy.
Consequently, the mechanism of geographic zoning is very complex and manifests itself ambiguously in different parts geographic envelope, in various components and constituent parts it, as well as in various processes occurring within the geographic envelope.
The first result of the zonal distribution of radiant energy is the ZONALITY of the RADIATION BALANCE on the Earth's surface. The maximum of total radiation falls on the 20-30th latitudes in both hemispheres, because the atmosphere here is transparent, the radiant energy entering the surface of the Earth and converted into thermal energy, is spent on evaporation and heat transfer to the atmosphere. Another important regularity that depends on the uneven distribution of heat is the AIR MASS ZONALITY, ATMOSPHERIC CIRCULATION AND MOISTURE CYCLE.
Air masses:
Equatorial (warm and humid)
Tropical (warm and dry)
Moderate (dry and wet, cool)
Antarctic, arctic (cold, dry)
Air masses heat up differently, therefore, they have different densities and there is a violation of thermodynamic equilibrium in the troposphere and, as a result, the circulation of air masses. If the Earth did not rotate around its axis, then the circulation of air masses would be primitive, i.e. in the northern hemisphere, air masses would have a direction from north to south, and in the southern hemisphere, from south to north. But as a result of the Coriolis force, circulation zones are formed, which correspond to the zonal types of air masses:
equatorial zone- low pressure, ascending air currents, calm prevails.
tropical zone- high pressure, the predominance of the eastern rhumb of air masses, which change in the northern hemisphere to the northeast, and in the south - to the southeast.
temperate zone– low pressure, western air transport.
polar zone- low pressure, easterly winds.
Transition zones: subarctic, subtropical, subequatorial. In which in summer the circulation shifts in accordance with the hemisphere to the pole, and in winter to the equator. In landscape science, 7 circulation zones are distinguished.
Atmospheric circulation is a mechanism for the redistribution of heat and moisture. If this pattern did not exist, then the globe there would be sharp boundaries between all zonal, temperature differences. The zonal distribution of solar heat is reflected by the distribution of the planet's thermal zones:
Hot– average annual temperature >20 o
2 moderate
2 cold when the temperature of the warmest month< +10 о.
Inside the cold belt, areas of eternal frost (ice zones) are distinguished when the temperature of the warmest month is below 0.
Zonal circulation of the atmosphere is associated with moisture and moisture circulation. Moisture circulation and humidification have their own zonal specifics when maxima are distinguished in the distribution of precipitation (usually there are 3 of them) - one at the equator, 2 in temperate latitudes. 4 minima - 2 in the polar latitudes, 2 in the tropics. The amount of precipitation does not determine the conditions for the moisture supply of landscapes (in the steppes up to 500 mm, but moisture is insufficient, and in the tundra 300-350 mm, moisture is excessive). Therefore, the moisture content is affected by the moisture coefficient.
The relief is also subject to zonality, but mainly morphosculptural types of relief, which are formed under the influence of exogenous processes, and they do not appear everywhere in the same way, depending on climatic conditions. Groundwater is also subject to the process of zonality. At the same depth, for example, they are located in the zone of broad-leaved foxes and steppes, they may differ in different degrees of mineralization, which are determined by different feeding methods. groundwater, varying degrees of evaporation. Thus, zoning is a universal geographical regularity, which manifests itself in all landscape-forming processes and in the distribution of natural complexes on the earth's surface.
Zoning must be considered in historical terms, because. it has evolved over hundreds of millions of years of geological history. The most ancient are the equatorial landscapes, which have existed since the middle of the Paleozoic. Many landscapes were influenced by the Paleogene-Neogene stages of development, especially in temperate latitudes. Pleistocene glaciation, when periods of glacial and interglacial periods were observed, the boundaries of landscapes shifted. The youngest natural zone yavl. Tundra zone. When considering the patterns of latitudinal zonality, the most important factor is macroclimatic conditions. The most inert factor is the geological structure and relief.
Types and classes of landscapes
The type of landscapes depends on zonal features, the most important of which are the ratios of heat and moisture, which determine the regime of surface and ground waters, the nature and direction of the main natural processes, the composition and structure of phyto- and zoocenoses. The types are tundra, forest, forest-steppe, desert and other landscapes. A.G. Isachenko considers the type of landscapes to be the highest unit of classification, and the class of landscapes is subordinate to the type.
To isolate the genus of landscapes, V.A. Nikolaev puts forward the genetic type of relief as the main criterion, and G.I. Yurenkov - provincial features of landscape types (Eastern European landscapes of mixed forests, Far Eastern landscapes of mixed forests, etc.).
Landscape type is the smallest unit of classification, distinguished either by the genetic features of the territory (A.G. Isachenko, N.L. Beruchashvili, G.I. Yurenkov), or by the structure of dominant tracts (V.A. Nikolaev).
Along with the listed basic units of landscape classification, there are intermediate ones - subclass, subtype, subgenus, subspecies, etc. For example, in the class of plains there may be subclasses of elevated and lowland landscapes; in the forest type - subtypes of northern taiga, middle taiga, southern taiga landscapes. The separation of such categories is dictated by the collected and elaborated material, the degree of its detail and reliability, and the scale of the map. Like the main ones, intermediate units occupy a strictly defined place in the taxonomic system and obey all the rules of classification.
Any classification presupposes some formalization, ordering and generalization of concepts. IN most generalization is inherent in the higher units of classification (departments, classes, types). Their differentiation is made according to the most important, essential features, against which the diversity of subordinates only emphasizes the complexity. internal structure large PTK. The minimum degree of generalization is characteristic of landscape types as relatively homogeneous sections.
The first classification of Belarusian landscapes was published by V.A. Dementiev and G.I. Martsinkevich in 1968. The main principle of classification was genetic. Its main drawback is the lack of a clear system of classification units.
The modern classification of landscapes of the Republic of Belarus has been developed in relation to a map at a scale of 1:600 OOO (authors N.K. Klitsunova, G.I. Martsinkevich, L.V. Loginova, G.T. Kharanicheva, scientific editor A.G. Isachenko), published in 1984. It takes into account the experience of researchers, embodied in the creation of landscape maps of Kazakhstan, Ukraine, Lithuania, the Non-Chernozem center of Russia. The highest classification unit is the class of landscapes. The territory of Belarus is entirely located within the East European platform with a flat relief and a clearly defined structure of latitudinal zones, therefore its landscapes belong to the class of flat ones. The next unit - the type of landscapes - is singled out taking into account bioclimatic factors. The position of the territory of Belarus in temperate latitudes with favorable conditions for the growth of forests predetermined that its NTC belongs to the temperate continental forest type of landscapes. At the same time, the length of the territory from north to south for more than 500 km is due to changes in the hydrothermal regime in this direction. On this basis, two subtypes of landscapes are distinguished: subtaiga (mixed-forest) and woodland (broad-leaved-forest). The first subtype covers the northern and central, the second - the southern parts of the republic. The border between them runs along the northern outskirts of the Belarusian Polissya.
What determines the formation of natural zones? What natural areas stand out on our planet? You can answer these and some other questions by reading this article.
Natural zoning: the formation of natural zones on the territory
The so-called our planet is the largest natural complex. It is very heterogeneous, both in the vertical section (which is expressed in vertical zonality) and in the horizontal (latitudinal), which is expressed in the presence of various natural zones on Earth. The formation of natural zones depends on several factors. And in this article we will talk about the latitudinal heterogeneity of the geographic envelope.
This is a component of the geographical shell, which is distinguished by a certain set of natural components with its own characteristics. These components include the following:
- climatic conditions;
- the nature of the relief;
- hydrological network of the territory;
- soil structure;
- organic world.
It should be noted that the formation of natural zones depends on the first component. However, natural areas receive their names, as a rule, according to the nature of their vegetation. After all, flora is the brightest component of any landscape. In other words, vegetation acts as a kind of indicator that reflects the deep (those that are hidden from our eyes) processes of the formation of a natural complex.
It should be noted that the natural zone is the highest step in the hierarchy of the physical and geographical zoning of the planet.
Factors of natural zoning
We list all the factors in the formation of natural zones on Earth. So, the formation of natural zones depends on the following factors:
- Climatic features of the territory (this group of factors should include the temperature regime, the nature of moisture, as well as the properties of the air masses that dominate the territory).
- The general nature of the relief (this criterion, as a rule, affects only the configuration, the boundaries of a particular natural zone).
The formation of natural zones can also be influenced by proximity to the ocean, or the presence of powerful ocean currents off the coast. However, all these factors are secondary. The main root cause of natural zonality is that different parts (belts) of our planet receive unequal amounts of solar heat and moisture.
Natural areas of the world
What natural zones are distinguished today by geographers on the body of our planet? Let's list them from the poles - to the equator:
- Arctic (and Antarctic) deserts.
- Tundra and forest tundra.
- Taiga.
- Broadleaved forest zone.
- Forest-steppe.
- Steppe (or prairie).
- Semi-desert and desert zone.
- Savannah zone.
- Tropical rainforest zone.
- Humid zone (hylaea).
- The zone of rain (monsoon) forests.
If we look at the map of the natural zonality of the planet, we will see that all natural zones are located on it in the form of sublatitudinal belts. That is, these zones, as a rule, extend from west to east. Sometimes this sublatitudinal direction can be violated. The reason for this, as we have already said, is the features of the relief of a particular territory.
It is also worth noting that there are simply no clear boundaries between natural areas (as shown on the map). So, almost each of the zones smoothly "flows" into the neighboring one. At the same time, border "zones" can very often form at the junction. For example, such are semi-desert or forest-steppe zones.
Conclusion
So, we found out that the formation of natural zones depends on many factors. The main ones are the ratio of heat and moisture in a particular area, the properties of the prevailing air masses, the nature of the relief, and so on. The set of these factors is the same for any territory: mainland, country or small area.
Geographers distinguish over a dozen large natural zones on the surface of our planet, which are elongated in the form of belts and replace each other from the equator to the polar latitudes.
Natural zones of the Earth
Comprehensive Scientific research nature allowed V. V. Dokuchaev in 1898 to formulate the law of geographical zoning, according to which climate, water, soil, relief, flora and fauna in a certain area are closely interconnected and should be studied as a whole. He proposed dividing the Earth's surface into zones that naturally repeat themselves in the Northern and Southern hemispheres.
Different geographical (natural) zones Earth are characterized by a certain combination of heat and moisture, soils, flora and fauna and, as a result, by the peculiarities of the economic activity of their population. These are zones of forests, steppes, deserts, tundra, savannas, as well as transitional zones of forest-tundra, semi-deserts, forest-tundra. The names of natural areas are traditionally given according to the prevailing type of vegetation, which reflects the most important features of the landscape.
The regular change of vegetation is an indicator of a general increase in heat. In the tundra, the average temperature of the warmest month of the year - July - does not exceed + 10 ° С, in the taiga it fluctuates between + 10 ... + 18 ° С in the strip of deciduous and mixed forests + 18 ... + 20 ° С, in the steppe and forest-steppe +22 ... + 24 ° С, in semi-deserts and deserts - above +30 ° С.
Most animal organisms remain active at temperatures from 0 to +30°C. However, temperatures from + 10 ° C and above are considered the best for growth and development. Obviously, such a thermal regime is characteristic of the equatorial, subequatorial, tropical, subtropical, and temperate climatic zones of the Earth. The intensity of vegetation development in natural areas also depends on the amount of precipitation. Compare, for example, their number in the zone of forests and deserts (see map of the atlas).
So, natural areas- These are natural complexes that occupy large areas and are characterized by the dominance of one zonal type of landscape. They are formed mainly under the influence of climate - the features of the distribution of heat and moisture, their ratio. Each natural zone has its own type of soil, vegetation and wildlife.
The appearance of the natural zone is determined by the type of vegetation cover. But the nature of vegetation depends on climatic conditions - thermal conditions, moisture, illumination, soils, etc.
As a rule, natural zones are elongated in the form of wide strips from west to east. There are no clear boundaries between them, they gradually pass into one another. The latitudinal location of natural zones is disturbed by the uneven distribution of land and ocean, relief, distance from the ocean.
General characteristics of the main natural zones of the Earth
Let us characterize the main natural zones of the Earth, starting from the equator and moving towards the poles.
Forests are located on all continents of the Earth, except for Antarctica. Forest zones have both common features and special features that are characteristic only of the taiga, mixed and broad-leaved forests or tropical forests.
The common features of the forest zone include: warm or hot summers, a fairly large amount of precipitation (from 600 to 1000 or more mm per year), large full-flowing rivers, and the predominance of woody vegetation. The equatorial forests, which occupy 6% of the land, receive the greatest amount of heat and moisture. They rightfully hold the first place among the forest zones of the Earth in terms of the diversity of plants and animals. 4/5 of all plant species grow here and 1/2 of all land animal species live.
The climate of the equatorial forests is hot and humid. Average annual temperatures are +24... +28°С. The annual amount of precipitation is more than 1000 mm. It is in the equatorial forest that you can find the largest number of ancient animal species, such as amphibians: frogs, newts, salamanders, toads or marsupials: opossums in America, possums in Australia, tenrecs in Africa, lemurs in Madagascar, loris in Asia; ancient animals are also such inhabitants of the equatorial forests as armadillos, anteaters, pangolins.
In the equatorial forests, the richest vegetation is located in several tiers. Many species of birds live in the crowns of trees: hummingbirds, hornbills, birds of paradise, crowned pigeons, numerous species of parrots: cockatoo, macaw, Amazon, Jaco. These birds have tenacious paws and strong beaks: they not only fly, but also climb trees beautifully. Animals that live in the crowns of trees also have tenacious paws and a tail: sloths, monkeys, howler monkeys, flying foxes, tree kangaroos. The largest animal that lives in the crowns of trees is the gorilla. In such forests, many beautiful butterflies and other insects live: termites, ants, etc. Various types of snakes. Anaconda - the largest snake in the world, reaches a length of 10 m or more. The high-water rivers of the equatorial forests are rich in fish.
The equatorial forests occupy the largest areas in South America, in the Amazon River basin, and in Africa - in the Congo River basin. The Amazon is the deepest river in the world. Every second it carries 220 thousand m3 of water into the Atlantic Ocean. The Congo is the second largest river in the world. Equatorial forests are also common on the islands of the Malaysian archipelago and Oceania, in the southeastern regions of Asia, in northeastern Australia (see the map in the atlas).
Valuable tree species: mahogany, black, yellow - the wealth of equatorial forests. The harvesting of valuable wood species threatens the preservation of the Earth's unique forests. Space images have shown that in a number of areas of the Amazon, forest destruction is proceeding at a catastrophic pace, many times faster than their restoration. At the same time, many species of unique plants and animals are disappearing.
Variable wet monsoon forests
Variably humid monsoon forests can also be found on all continents of the Earth, except for Antarctica. If it is summer all the time in the equatorial forests, then three seasons are pronounced here: dry cool (November-February) - winter monsoon; dry hot (March-May) - transitional season; humid hot (June-October) - summer monsoon. The hottest month is May, when the sun is almost at its zenith, the rivers dry up, the trees shed their leaves, the grass turns yellow.
The summer monsoon comes at the end of May with gale-force winds, thunderstorms, and heavy rains. Nature comes to life. Due to the alternation of dry and wet seasons, monsoon forests are called variable wet.
The monsoon forests of India are located in the tropical climate zone. Valuable species of trees grow here, distinguished by the strength and durability of wood: teak, sal, sandalwood, satin and ironwood. Teak wood is not afraid of fire and water, it is widely used for building ships. Sal also has a durable and strong wood. Sandalwood and satin wood are used in the manufacture of varnishes and paints.
The fauna of the Indian jungle is rich and varied: elephants, bulls, rhinos, monkeys. Lots of birds and reptiles.
Monsoon forests of tropical and subtropical regions are also characteristic of South-East Asia, Central and South America, northern and northeastern regions of Australia (see the map in the atlas).
Temperate monsoon forests
Temperate monsoon forests are found only in Eurasia. The Ussuri taiga is a special place in the Far East. This is a real thicket: the forests are multi-tiered, dense, intertwined with lianas and wild grapes. Cedar, walnut, linden, ash and oak grow here. Rough vegetation is the result of an abundance of seasonal rainfall and a rather mild climate. Here you can meet the Ussuri tiger - the largest representative of its kind.
The rivers of the monsoon forests are rain-fed and flood during the summer monsoon rains. The largest of them are the Ganges, Indus, Amur.
The monsoon forests are heavily cut down. According to experts, in Eurasia only 5% of the former forests remained. Monsoon forests suffered not so much from forestry, but also from agriculture. It is known that the largest agricultural civilizations appeared on fertile soils in the valleys of the Ganges, Irrawaddy, Indus and their tributaries. The development of agriculture required new territories - forests were cut down. Farming has adapted over the centuries to alternating wet and dry seasons. The main agricultural season is the wet monsoon period. The most important crops - rice, jute, sugarcane - are dated for it. In the dry cool season, barley, legumes, and potatoes are planted. In the dry hot season, agriculture is possible only with artificial irrigation. The monsoon is capricious, its delay leads to severe droughts and the death of crops. Therefore, artificial irrigation is necessary.
temperate forests
Temperate forests occupy significant areas in Eurasia and North America (see map in the atlas).
In the northern regions - this is the taiga, to the south - mixed and broad-leaved forests. In the forest zone of the temperate zone, the seasons of the year are pronounced. Average temperatures in January are negative everywhere, in some places up to -40°С, in July + 10 ... + 20°С; the amount of precipitation is 300-1000 mm per year. Vegetation of plants in winter stops, for several months there is a snow cover.
Spruce, fir, pine, larch grow both in the taiga of North America and in the taiga of Eurasia. The animal world also has a lot in common. The bear is the master of the taiga. True, in the Siberian taiga it is called a brown bear, and in the taiga of Canada it is called a grizzly bear. You can meet red lynx, elk, wolf, as well as marten, ermine, wolverine, sable. The largest rivers of Siberia - the Ob, Irtysh, Yenisei, Lena - flow through the taiga zone, which are second only to the rivers of the equatorial forest zone in terms of flow.
To the south, the climate becomes milder: mixed and broad-leaved forests grow here, consisting of such species as birch, oak, maple, linden, among which there are also conifers. Typical for the forests of North America are: white oak, sugar maple, yellow birch. Red deer, elk, wild boar, hare; from predators - a wolf and a fox - representatives of animal world of this zone known to us.
If the northern taiga is classified by scientists-geographers as a zone slightly modified by man, then mixed and broad-leaved forests have been cut down almost everywhere. Their place was taken by agricultural areas, such as the "corn belt" in the United States, in this zone many cities and highways are concentrated. In Europe and North America, the natural landscapes of these forests have been preserved only in mountainous regions.
Savannah
Savannah is a natural zone of low latitudes in the subequatorial, tropical and subtropical zones of the Northern and Southern Hemispheres. It occupies about 40% of the territory of Africa (south of the Sahara), distributed in South and Central America, Southeast Asia, Australia (see the map in the atlas). The savanna is dominated by herbaceous vegetation with isolated trees or groups of trees (acacia, eucalyptus, baobab) and shrubs.
The fauna of the African savannas is surprisingly diverse. To adapt to the conditions of endless dry spaces, nature endowed animals unique properties. For example, the giraffe is considered the tallest animal on Earth. Its height exceeds 5 m, it has a long tongue (about 50 cm). All this is necessary for a giraffe in order to reach the high branches of acacias. Crowns of acacias begin at a height of 5 m, and giraffes have practically no competitors, calmly eating tree branches. Typical animals of the savannas are zebras, elephants, ostriches.
steppes
Steppes are found on all continents of the Earth, except for Antarctica (in the temperate and subtropical zones of the Northern and Southern Hemispheres). They are distinguished by an abundance of solar heat, low rainfall (up to 400 mm per year), as well as warm or hot summers. The main vegetation of the steppes is grasses. The steppes are called differently. In South America, the tropical steppes are called pampas, which in the language of the Indians means "a large expanse without a forest." Animals characteristic of the pampa are the llama, the armadillo, the viscacha, a rodent that looks like a rabbit.
In North America, the steppes are called prairies. They are located in both temperate and subtropical climatic zones. The "kings" of the American prairies have long been bison. By the end of the 19th century, they were almost completely exterminated. Currently, through the efforts of the state and the public, the number of bison is being restored. Another inhabitant of the prairies is the coyote - the steppe wolf. On the banks of the rivers in the bushes you can meet a large spotted cat - a jaguar. The peccary is a small boar-like animal also typical of the prairies.
The steppes of Eurasia are located in the temperate zone. They are very different from the American prairies and African savannas. It has a drier, sharply continental climate. It is very cold in winter (average temperature - 20°С), and very hot in summer (average temperature + 25°С), strong winds. In summer, the vegetation of the steppes is sparse, but in spring the steppe is transformed: it blooms with many varieties of lilies and poppies, tulips.
The flowering time does not last long, about 10 days. Then a drought sets in, the steppe dries up, the colors fade, and by autumn everything takes on a yellow-gray color.
The most fertile soils of the Earth are located in the steppes, so they are almost completely plowed up. The treeless expanses of the steppes of the temperate zone are distinguished by strong winds. Here, wind erosion of soils is very intensive - dust storms are frequent. To preserve soil fertility, forest belts are planted, organic fertilizers and light agricultural machinery are used.
desert
Deserts occupy vast spaces - up to 10% of the Earth's land mass. They are located on all continents and in different climatic zones: temperate, subtropical, tropical and even polar.
There are common features in the climate of the deserts of the tropical and temperate zones. Firstly, the abundance of solar heat, secondly, the large amplitude of temperatures in winter and summer, day and night, and thirdly, a small amount of precipitation (up to 150 mm per year). However, the latter feature is also characteristic of the polar deserts.
In the deserts of the tropical zone, the average summer temperature is +30°C, winter + 10°C. The greatest tropical deserts of the Earth are located in Africa: Sahara, Kalahari, Namib.
Desert plants and animals adapt to dry and hot climates. So, for example, a giant cactus can store up to 3000 liters of water and “not drink” for up to two years; and the Welwitschia plant, found in the Namib Desert, is able to absorb water from the air. A camel is an indispensable helper of a person in the desert. He can be without food and water for a long time, storing them in his humps.
The largest desert in Asia, Rub al-Khali, located on the Arabian Peninsula, is also located in the tropical zone. The desert regions of North and South America and Australia are located in tropical and subtropical climatic zones.
The deserts of the temperate zone of Eurasia are also characterized by a low amount of precipitation and a large amplitude of temperatures, both annual and daily. However, they are characterized by lower winter temperatures and a pronounced flowering period in spring. Such deserts are located in Central Asia east of the Caspian Sea. The fauna here is represented by various species of snakes, rodents, scorpions, turtles, lizards. A typical plant is saxaul.
polar deserts
Polar deserts are located in the polar regions of the Earth. An absolute minimum temperature of 89.2°C has been recorded in Antarctica.
Average winter temperatures are -30°С, summer - 0°С. Just like in the deserts of the tropical and temperate zones, little precipitation falls in the polar desert, mainly in the form of snow. The polar night here lasts almost half a year, the polar day lasts almost half a year. Antarctica is considered the highest continent on Earth, given the thickness of its ice shell of 4 km.
The indigenous inhabitants of the polar deserts of Antarctica are emperor penguins. They cannot fly, but they are excellent swimmers. They can dive to great depths and swim great distances, escaping from their enemies - seals.
The northern polar region of the Earth - the Arctic - got its name from the ancient Greek arcticos - northern. The southern, as it were, opposite polar region is Antarctica (anti - against). The Arctic occupies the island of Greenland, the islands of the Canadian Arctic Archipelago, as well as the islands and waters of the Arctic Ocean. This area is covered with snow and ice throughout the year. The owner of these places is considered to be a polar bear.
Tundra
Tundra is a treeless natural area with vegetation of mosses, lichens and creeping shrubs. Tundra is common in the subarctic climatic zone only in North America and Eurasia, which are characterized by harsh climatic conditions (little solar heat, low temperatures, short cold summers, low rainfall).
Moss lichen was called "reindeer moss" because it is the main food for reindeer. Arctic foxes also live in the tundra, lemmings are small rodents. Among the sparse vegetation there are berry bushes: blueberries, lingonberries, blueberries, as well as dwarf trees: birch, willow.
Permafrost in the soil is a phenomenon characteristic of the tundra, as well as the Siberian taiga. It is worth starting to dig a hole, as at a depth of about 1 m there will be a frozen layer of earth several tens of meters thick. This phenomenon must be taken into account in the construction, industrial and agricultural development of the territory.
In the tundra, everything grows very slowly. It is with this that the need for careful attention to its nature is connected. For example, pastures damaged by deer are restored only after 15-20 years.
Altitudinal zonality
Unlike flat territories, climatic zones and natural zones in the mountains change according to the law of vertical zonality, i.e., from bottom to top. This is because the air temperature decreases with altitude. Consider, as an example, the greatest mountain system world - the Himalayas. Almost all natural zones of the Earth are represented here: at the foot grows a tropical forest, at an altitude of 1500 m it is replaced by broad-leaved forests, which in turn turn into mixed ones at an altitude of 2000 m. Further, as you climb into the mountains, coniferous forests of Himalayan pine, fir and juniper begin to predominate. In winter, there is snow for a long time and frosts persist.
Above 3500 m, shrubs and alpine meadows begin, they are called "alpine". In summer, the meadows are covered with a carpet of brightly flowering herbs - poppies, primroses, gentians. Gradually the grasses become lower. Approximately from a height of 4500 m, eternal snow and ice lie. The climatic conditions here are very harsh. Rare species of animals live in the mountains: mountain goat, chamois, argali, snow leopard.
Latitudinal zonality in the ocean
The world ocean occupies more than 2/3 of the planet's surface. Physical Properties And chemical composition ocean waters are relatively constant and create an environment conducive to life. It is especially important for the life of plants and animals that oxygen and carbon dioxide coming from the air dissolve in water. Photosynthesis of algae occurs mainly in the upper layer of water (up to 100 m).
Marine organisms live mainly in the surface layer of water illuminated by the Sun. These are the smallest plant and animal organisms - plankton (bacteria, algae, smallest animals), various fish and marine mammals (dolphins, whales, seals, etc.), squids, sea snakes and turtles.
There is life on the sea floor too. These are bottom algae, corals, crustaceans, molluscs. They are called benthos (from the Greek benthos - deep). The biomass of the World Ocean is 1000 times smaller than the biomass of the land of the Earth.
The distribution of life in oceans uneven and depends on the amount of solar energy received on its surface. Polar waters are poor in plankton due to low temperatures and long polar nights. The greatest amount of plankton develops in the waters of the temperate zone in summer. The abundance of plankton attracts fish here. The temperate zones of the Earth are the most fishy areas of the oceans. In the tropical zone, the amount of plankton again decreases due to the high salinity of the water and high temperatures.
Formation of natural zones
From today's topic, we have learned how diverse the natural complexes of our planet are. The natural zones of the Earth are full of evergreen forests, endless steppes, various mountain ranges, hot and icy deserts.
Each corner of our planet is distinguished by its uniqueness, diverse climate, relief, flora and fauna, and therefore various natural zones are formed on the territories of each continent.
Let's try to figure out what natural zones are, how they formed, and what was the impetus for their formation.
Natural zones include such complexes that have similar soils, vegetation, wildlife and the similarity of the temperature regime. Natural zones got their names according to the type of vegetation, and they bear such names as the zone of taiga or broad-leaved forests, etc.
Natural areas are diverse, due to the uneven redistribution of solar energy on the Earth's surface. This is the main reason for the heterogeneity of the geographic envelope.
After all, if we consider one of the climatic zones, we can see that those parts of the belt that are closer to the ocean are more humid than its continental parts. And this reason lies not so much in the amount of precipitation, but rather in the ratio of heat and moisture. Because of this, on some continents we observe a more humid climate, and on the other - arid.
And with the help of the redistribution of solar heat, we see how the same amount of moisture in some climatic zones leads to excess moisture, and in others - to their lack.
So, for example, in a hot tropical zone, a lack of moisture can cause drought and the formation of desert territories, while in the subtropics, an excess of moisture contributes to the formation of swamps.
So you learned that due to the difference in the amount of solar heat and moisture, various natural zones were formed.
Patterns of placement of natural zones
The natural zones of the Earth have clear patterns of their location, extending in a latitudinal direction and changing from north to south. Most often, a change in natural zones is observed in the direction from the coast, making its way deep into the mainland.
In mountainous areas there is an altitudinal zonality, which changes one zone for another, starting from the foot and moving towards the mountain peaks.
In the oceans, the change of zones occurs from the equator to the poles. Here, changes in natural zones are reflected in the surface composition of waters, as well as the difference in vegetation and wildlife.
Features of the natural zones of the continents
Since the planet Earth has a spherical surface, the Sun also heats it unevenly. Those areas of the surface above which the Sun is high receive the most heat. And where the sun's rays only glide over the Earth, a more severe climate prevails.
And although vegetation and animals on different continents have similar features, they are influenced by climate, topography, geology and people. Therefore, it so happened historically that due to changes in the relief and climate, different types of plants and animals live on different continents.
There are continents where endemics are found, on which only a certain type of living creatures and plants live, which are characteristic of these continents. So, for example, polar bears can only be found in nature in the Arctic, and kangaroos in Australia. But in African and South American shrouds, similar species are found, although they have certain differences.
But human activity contributes to the changes that occur in the geographical shell, and under such influence, natural areas also change.
Questions and tasks for preparing for the exam
1. Make a diagram of the interaction of natural components in the natural complex and explain it.
2. How do the concepts of "natural complex", "geographical envelope", "biosphere", "natural zone" relate to each other? Show with a diagram.
3. Name the zonal soil type for the tundra, taiga, zones of mixed and broad-leaved forests.
4. Where is the soil cover more difficult to restore: in the steppes of the South of Russia or in the tundra? Why?
5. What is the reason for the difference in the thickness of the fertile soil layer in different natural zones? What does soil fertility depend on?
6. What types of plants and animals are characteristic of the tundra and why?
7. What organisms live on the surface of the oceans?
8. Which of the following animals can be found in the African savannah: rhinoceros, lion, giraffe, tiger, tapir, baboon, llama, hedgehog, zebra, hyena?
9. In what forests is it impossible to find out its age from a cut of a cut tree?
10. What measures, in your opinion, will help preserve the human habitat?
Maksakovskiy V.P., Petrova N.N., Physical and economical geography peace. - M.: Iris-press, 2010. - 368 pp.: ill.