Natural sushi complexes. Natural complexes
- Name several natural complexes in your area. Briefly describe one of them and indicate the relationships between the components.
- From natural history and biology courses, remember how soils are formed and what kind of soils you know.
Natural complexes sushi. The geographical envelope, being integral, is heterogeneous at different latitudes, on land and in the ocean.
Due to the uneven supply of solar heat to the earth's surface, the geographical envelope is very diverse. Near the equator, for example, where there is a lot of heat and moisture, nature is distinguished by the richness of living organisms that pass more quickly natural processes, in the polar regions, on the contrary, slowly flowing processes and poverty of life. At the same latitudes, nature can also be different. It depends on the terrain, on the distance from the ocean. Therefore, the geographical envelope can be divided into areas of different sizes, territories or natural-territorial complexes (abbreviated as natural complexes, or PC).
The formation of any natural complex took place long time. On land, it was carried out under the influence of the interaction of natural components: rocks, climate, air masses, water, plants, animals, soils (Fig. 32). All components in the natural complex, as in the geographical shell, are intertwined with each other and form an integral natural complex; metabolism and energy also occur in it. A natural complex is a section of the earth's surface that is distinguished by the characteristics of natural components that are in complex interaction. Each natural complex has more or less clearly defined boundaries, has a natural unity, manifested in its appearance(for example, forest, swamp, mountain range, lake, etc.).
Rice. 32. Relationships between the components of the natural complex
Natural complexes of the ocean, unlike land, consist of the following components: water with gases dissolved in it, plants and animals, rocks and bottom topography. In the World Ocean there are large natural complexes - individual oceans, smaller ones - seas, bays, straits, etc. In addition, natural complexes are distinguished in the ocean surface layers water, various layers of water and the ocean floor.
Variety of natural complexes. There are natural complexes different sizes. They also differ in education. Very large natural complexes are continents and oceans. Their formation is determined by the structure earth's crust. On continents and oceans, smaller complexes are distinguished - parts of continents and oceans. Depending on the amount of solar heat, i.e. on geographic latitude, there are natural complexes of equatorial forests, tropical deserts, taiga, etc. Examples of small ones include, for example, a ravine, lake, river valley, sea bay. And the largest natural complex of the Earth is the geographical envelope.
All natural complexes experience enormous human influence. Many of them have already been greatly changed by centuries of human activity. Man has created new natural complexes: fields, gardens, cities, parks, etc. Such natural complexes are called anthropogenic (from the Greek “anthropos” - man).
- Using the text of the textbook, write down the components of the geographical shell in the left column of your notebook, the components of the natural complexes of the land in the middle column, and the components of the natural complexes of the ocean in the right column. What do the components of each natural complex have in common?
- What is a natural complex?
- How do natural complexes differ?
Natural resources are formed in natural environments and form certain combinations in space that change within the boundaries of natural-territorial complexes. On this basis, they can be divided into 2 groups: resources of natural components and resources of natural-territorial complexes.
Fig.1. Classification of natural resources by origin
1. Resources of natural components. Each type of this resource usually appears in one of the components of the landscape shell. It is controlled by the same natural factors, which create this natural component and affect its characteristics. Resources are distinguished according to their belonging to the components of the landscape shell:
Mineral,
Climatic,
Vegetables,
Land,
Soil,
Animal world.
This classification is very often used in Russian and foreign literature. When using the above classification, much attention should be paid to the patterns of spatial and temporal formation individual species resources, their quantitative, quality characteristics, volumes of natural replenishment of reserves. Scientific understanding of the entire complex of natural processes involved in the creation and accumulation of a natural resource allows us to more correctly calculate the role and place of a particular group of resources in the process of social production, the economic system, and most importantly, gives us the opportunity to identify the maximum volumes of resource removal from the natural environment, without allowing it to deplete or deteriorate in quality.
2. Resources of natural-territorial complexes. At this level of subdivision, the complexity of the natural resource potential of the territory is considered, arising from the corresponding complex structure of the landscape envelope itself. Each landscape has a certain set of different types of natural resources. Depending on the properties of the landscape, its place in the overall structure of the landscape shell, and the combination of types of resources, their quantitative and qualitative characteristics change very significantly, determining the possibilities for the development and organization of material production. Conditions often arise when one or several resources determine the direction of economic development of an entire region. Almost any landscape has climatic, water, land, soil and other resources, but the possibilities for economic use are very different. In one case, favorable conditions may arise for the extraction of mineral raw materials, in others - for the cultivation of valuable cultivated plants or for organization industrial production, resort complex, etc. On this basis, natural resource territorial complexes are identified according to the most preferred type of economic development. They are divided into:
Mining,
Agricultural,
Water management,
Forestry,
Residential,
Recreational, etc.
Using only one classification of resources by their origin is not enough, since it does not reflect economic significance resources and their economic role. Among the variety of classification systems for natural resources, reflecting their economic significance and role in the social production system, classification according to the direction and forms of economic use of resources is more often used.
CLASSIFICATION BY TYPES OF ECONOMIC USE
The main criterion for dividing resources in this classification is their assignment to various sectors of material production. On this basis, natural resources can be divided into resources of industrial and agricultural production.
1. Industrial production resources. This subgroup includes all types of natural raw materials that are used by industry. Due to the very large branching of industrial production, the presence of many industries consuming different types natural resources and, accordingly, advancing to them different requirements. Types of natural resources are divided in the following way:
Fig.2. Classification of natural resources by type of economic use
1) energy, These include various types of resources used today in the development of science and technology for energy production:
a) fossil fuels
b) hydropower resources are the energy of freely falling river waters, tidal wave energy sea waters and etc.;
c) sources of bioconversion energy - the use of fuel wood, the production of biogas from agricultural waste;
d) nuclear raw materials, they are used to produce nuclear energy;
2) non-energy including a subgroup of natural resources that supply raw materials for various industries industry or participate in production due to technological necessity:
a) minerals that do not belong to the group of stobiolites;
b) water used for industrial water supply;
c) lands occupied by industrial facilities and infrastructure facilities;
d) forest resources supplying raw materials for the wood chemicals and construction industry;
e) fishery resources belong to this subgroup conditionally, since currently fish production and processing of the catch have become industrial in nature.
2. Agricultural Resources combining types of resources involved in the creation of agricultural products:
a) agroclimatic - these are resources of heat and moisture, they are necessary for the production of cultivated plants or grazing of livestock;
b) soil and land resources - land and its upper layer– soil has a unique property and is considered both as a natural resource and as a means of production in crop production;
c) plant feed resources - resources of biocenoses that serve as a food supply for grazing livestock;
G) water resources– water used in crop production for irrigation, and in livestock farming – for watering and keeping livestock. Very often natural resources of the non-productive sphere or direct consumption are also highlighted. These are, first of all, resources taken from the natural environment, as well as recreational resources, resources of protected areas and a number of others.
CLASSIFICATION ACCORDING TO EXHAUSTABILITY
Fig.3. Classification of natural resources based on exhaustibility
When taking into account reserves of natural resources and the volume of their possible economic withdrawal, the idea of exhaustibility of reserves is used. A. Mintz proposed calling the classification based on this criterion ecological. All natural resources are divided into two groups according to their exhaustibility: exhaustible and inexhaustible.
1. Exhaustible Resources. They form in the earth's crust or landscape, but the volumes and rates of their formation are measured on a geological time scale. At the same time, the need for such resources from production or for the organization favorable conditions habitats of human society largely exceed the volumes and rates of natural replenishment. As a result, depletion of natural resources inevitably occurs. The group of exhaustible resources includes resources with unequal rates and volumes of formation. This allows for their further separation. Based on the intensity and speed of natural education, resources are divided into subgroups:
1. Non-renewable natural resources are resources that cannot be restored after their complete depletion (mineral resources). Some of the non-renewable resources may be replaceable (eg mineral fuel resources - nuclear and solar energy).
2. Renewable natural resources are resources that, as they are consumed, are reproduced under the influence of natural processes or conscious human efforts ( solar energy, the water cycle in nature, the maintenance of oxygen levels in the atmosphere by vegetation). Soil fertility requires human effort, in particular the application of fertilizers
3. Relatively renewable soils are, first of all, soils that have partially come out of agricultural use as a result of water and wind erosion or radioactive contamination, forest stands, and peat used as fuel. After a certain period of time (from hundreds to several thousand years), these resources can be used again.
The fact of the practical inexhaustibility of water resources on a planetary scale is well known. However, on the land surface, fresh water reserves are unevenly concentrated, and over vast areas there is a shortage of water suitable for use in water management systems. Arid and subarid areas suffer especially greatly from water shortages, where irrational water consumption is accompanied by rapid and often catastrophic depletion of water supplies. Therefore, it is necessary to accurately account for the amount of permissible withdrawal of water resources by region.
2 Inexhaustible resources. Among the bodies and natural phenomena of resource significance, there are those that are practically inexhaustible. These include climatic and water resources.
A) climate resources. The most stringent climate requirements are imposed Agriculture, recreational and forestry, industrial and civil construction, etc. Typically, climate resources mean the reserves of heat and moisture available to a specific area or region. Since these resources are formed in certain parts of the thermal and water cycles, constantly operating over the planet as a whole and over its individual regions, the reserves of heat and moisture can be considered inexhaustible within certain quantitative limits, precisely established for each region.
B) Water resources planets. The earth has a colossal volume of water - about 1.5 billion cubic meters. km. However, 98% of this volume is the salty waters of the World Ocean, and only 28 million cubic meters. km – fresh waters. Since technologies for desalination of salty sea waters are already known, the waters of the World Ocean and salt lakes can be considered as potential water resources, the use of which in the future is quite possible. Subject to the principles of rational water use, these resources can be considered inexhaustible. However, if these principles are violated, the situation can sharply worsen, and even on a planetary scale there may be a shortage of clean fresh water. In the meantime, the natural environment annually “gives” humanity 10 times more water than it needs to satisfy a wide variety of needs.
“Natural zones of the cold belt” - Natural zones of the earth. Natural zones of the temperate zone. Natural zones of the cold zone. Taiga. Tundra zone. Tundra ecosystem. Deserts. Taiga mixed broadleaf forests. " Ecological systems" In the direction from the pole to the equator, natural zones replace each other in a certain order. cold moderate hot moderate cold.
“Natural zonality” - Make a description of the natural zone. Agroclimatic resources of a natural zone Problems of protection of a natural zone. What are indirect and direct impacts on natural areas? Learning new material. Human economic activity in natural areas. Name and geographical location. The doctrine of natural zones.
“Natural complexes and zones” - Equator. Water. Precipitation Relief. Man has created new natural complexes. Warmth. Sea. Equatorial forest. Variety of natural complexes. Components of the natural complex. Climate is the leading component of the natural complex. Give examples of natural complexes. Change of natural areas. Plants. Desert.
“Geography of natural complexes” - The entire hydrosphere. Interrelation of organisms Natural complex Geographical envelope and biosphere. Atmosphere. Lithosphere. The entire biosphere. "Component" - translated from Latin means " component the whole." Hydrosphere. Mountains. Large natural complexes - continents and oceans. “Complex” means “combination” in Latin.
"Savannas and woodlands" - Africa has the most diverse animal world savannah Dry. Soils. Australia. South America. Climatic features. Savannas and woodlands. Humus accumulates in the soil. Each continent has its own unique flora of savannas and woodlands. Animal world. Definition of a natural area. Climatic features, soils, flora and fauna.
"Natural areas of the world" - Tapir. Identify the natural area from the description. Steppes (pampa). Savannah-. The reason for the change in natural zones? Throughout the year. Lives near water, swims and dives, feeds on stems aquatic plants. Natural areas South America. Vnazhnye villages (selva). You need to warn your geography teacher about your delay in the semi-deserts of Patagonia.
1. Structure and properties of the geographical shell
2. Natural complexes of land and ocean
3. Natural zoning
4. Human development of the Earth. Countries of the world
1. Structure and properties of the geographical shell
Before the appearance of life on Earth, its outer, single shell was made up of three interconnected shells: the lithosphere, the atmosphere and the hydrosphere. With the advent of living organisms - the biosphere, this outer shell has changed significantly. All its components - components - have also changed. The shell of the Earth, within which the lower layers of the atmosphere, the upper parts of the lithosphere, the entire hydrosphere and the biosphere mutually penetrate each other and interact, is called the geographic (earth) shell. All components of the geographic shell do not exist in isolation; they interact with each other. Thus, water and air, penetrating through cracks and pores deep into rocks, participate in weathering processes, change them and at the same time change themselves. Rivers and groundwater, moving minerals, participate in changes in relief. Rock particles rise high into the atmosphere during volcanic eruptions, strong winds. A lot of salts are contained in the hydrosphere. Water and minerals are part of all living organisms. Living organisms, dying, form huge strata of rocks. Different scientists draw the upper and lower boundaries of the geographic envelope in different ways. It has no sharp boundaries. Many scientists believe that its thickness is on average 55 km. Compared to the size of the Earth, it is a thin film.
As a result of the interaction of components, the geographical shell has properties inherent only to it.
Only here there are substances in solid, liquid and gaseous states, which has great value for all processes occurring in the geographical shell, and above all for the emergence of life. Only here, near the solid surface of the Earth, life first arose, and then man and human society appeared, for the existence and development of which there are all the conditions: air, water, rocks and minerals, solar heat and light, soil, vegetation, bacterial and animal life .
All processes in the geographic shell occur under the influence of solar energy and, to a lesser extent, internal earthly sources energy. Changes in solar activity affect all processes of the geographic envelope. For example, during periods of increased solar activity, the magnetic storms, the rate of plant growth, reproduction and migration of insects changes, and the health of people, especially children and the elderly, worsens. The connection between the rhythms of solar activity and living organisms was shown by the Russian biophysicist Alexander Leonidovich Chizhevsky back in the 20-30s. XX century
The geographic envelope is sometimes called the natural environment or simply nature, meaning mainly the nature within the boundaries of the geographic envelope.
All components of the geographic shell are connected into a single whole through the circulation of substances and energy, due to which the exchange of substances between shells takes place. The circulation of matter and energy is the most important mechanism of natural processes of the geographical envelope. There are various cycles of matter and energy: air cycles in the atmosphere, the earth’s crust, water cycles, etc. For the geographic envelope great importance has a water cycle, which is carried out due to the movement of air masses. Water is one of the most amazing substances of nature, characterized by great mobility. Ability to change from liquid to solid or gaseous state with minor temperature changes, it allows water to accelerate various natural processes. Without water there can be no life. Water, being in the cycle, enters into close interactions with other components, connects them with each other and is an important factor in the formation of the geographical envelope.
The biological cycle plays a huge role in the life of the geographic envelope. In green plants, as is known, in the light from carbon dioxide and water, organic substances are formed that serve as food for animals. Animals and plants, after they die, are decomposed by bacteria and fungi into minerals, which are then reabsorbed by green plants. The same elements repeatedly form the organic substances of living organisms and repeatedly return to the mineral state.
The leading role in all circulations belongs to the air circulation in the troposphere, which includes the entire system of winds and vertical air movement. The movement of air in the troposphere draws in global cycle and the hydrosphere, forming the global water cycle. The intensity of other cycles also depends on it. The most active cycles occur in the equatorial and subequatorial belts. In the polar regions, on the contrary, they proceed especially slowly. All cycles are interconnected.
Each subsequent cycle is different from the previous ones. It does not form a vicious circle. Plants, for example, take from the soil nutrients, and when they die, they give up much more of them, since the organic mass of plants is created mainly due to atmospheric carbon dioxide, and not due to substances coming from the soil. Thanks to the cycles, the development of all components of nature and the geographic envelope as a whole occurs.
What makes our planet unique? Life! It is difficult to imagine our planet without plants and animals. In the most various forms it permeates not only the water and air elements, but also the upper layers of the earth's crust. The emergence of the biosphere is fundamentally important stage development of the geographical envelope and the entire Earth as a planet. the main role living organisms - ensuring the development of all life processes, which are based on solar energy and biological cycle substances and energy. Life processes consist of three main stages: the creation of organic matter as a result of photosynthesis primary production; transformation of primary (plant) products into secondary (animal) products; destruction of primary and secondary biological products by bacteria and fungi. Without these processes life is impossible. Living organisms include: plants, animals, bacteria and fungi. Each group (kingdom) of living organisms plays a specific role in the development of nature.
Life on our planet arose 3 billion years ago. Over the course of billions of years, all organisms developed, settled, changed in the process of development and, in turn, influenced the nature of the Earth - their habitat.
Under the influence of living organisms, there is more oxygen in the air and a decrease in carbon dioxide content. Green plants are the main source of atmospheric oxygen. Another thing was the composition of the World Ocean. Rocks appeared in the lithosphere organic origin. Deposits of coal and oil, most limestone deposits are the result of the activity of living organisms. The result of the activity of living organisms is also the formation of soils, thanks to the fertility of which plant life is possible. Thus, living organisms are a powerful factor in the transformation and development of the geographical envelope. The brilliant Russian scientist V.I. Vernadsky considered living organisms to be the most powerful force on the earth's surface in terms of their final results, transforming nature.
2. Natural complexes of land and ocean
The geographical envelope, being integral, is heterogeneous at different latitudes, on land and in the ocean. Due to the uneven supply of solar heat to the earth's surface, the geographical envelope is very diverse. Near the equator, for example, where there is a lot of heat and moisture, nature is distinguished by the richness of living organisms, faster-moving natural processes, in the polar regions, on the contrary, slow-flowing processes and poverty of life. At the same latitudes, nature can also be different. It depends on the terrain and distance from the ocean. Therefore, the geographic envelope can be divided into areas, territories, or natural-territorial complexes of different sizes (abbreviated as natural complexes, or PC). The formation of any natural complex took a long time. On land, it was carried out under the influence of the interaction of natural components: rocks, climate, air masses, water, plants, animals, soils. All components in the natural complex, as in the geographical shell, are intertwined with each other and form an integral natural complex; metabolism and energy also occur in it. A natural complex is a section of the earth's surface that is distinguished by the characteristics of natural components that are in complex interaction. Each natural complex has more or less clearly defined boundaries and has a natural unity, manifested in its external appearance (for example, a forest, a swamp, a mountain range, a lake, etc.).
Natural complexes of the ocean, unlike land, consist of the following components: water with gases dissolved in it, plants and animals, rocks and bottom topography. In the World Ocean there are large natural complexes - individual oceans, smaller ones - seas, bays, straits, etc. In addition, in the ocean there are natural complexes of surface layers of water, various layers of water and the ocean floor.
Natural complexes come in different sizes. They also differ in education. Very large natural complexes are continents and oceans. Their formation is determined by the structure of the earth's crust. On continents and oceans, smaller complexes are distinguished - parts of continents and oceans. Depending on the amount of solar heat, i.e. on geographic latitude, there are natural complexes of equatorial forests, tropical deserts, taiga, etc. Examples of small ones include, for example, a ravine, lake, river valley, sea bay. And the largest natural complex of the Earth is the geographical envelope.
The geographical envelope is not tripled equally everywhere, it has
"mosaic" structure and consists of individual natural complexes
(landscapes). Natural complex – This is a part of the earth's surface with relatively homogeneous natural conditions: climate, topography, soils, waters, flora and fauna.
Each natural complex consists of components between which there are close, historically established relationships, and a change in one of the components sooner or later leads to a change in the others.
The largest planetary natural complex is
geographical envelope, it is divided into natural complexes of a smaller rank. Separation geographic shell on natural complexes is due to two reasons: on the one hand, differences in the structure of the earth’s crust and the heterogeneity of the earth’s surface, and on the other, the unequal amount of solar heat received by its different areas. In accordance with this, zonal and azonal natural complexes are distinguished.
The largest azonal natural complexes are continents and oceans. Smaller - mountainous and flat areas within the continents ( West Siberian Plain, Caucasus, Andes, Amazonian lowland). The latter are divided into even smaller natural complexes (Northern, Central, Southern Andes). Natural complexes of the lowest rank include individual hills, river valleys, their slopes, etc.
The largest of the zonal natural complexes are geographical zones. They coincide with climatic zones and have the same names (equatorial, tropical, etc.). In turn, geographical zones consist of natural zones, which are distinguished by the ratio of heat and moisture.
Natural area is a large area of land with similar natural components - soils, vegetation, fauna, which are formed depending on the combination of heat and moisture.
The main component of a natural area is climate, since all other components depend on it. Vegetation has a great influence on the formation of soils and fauna and is itself dependent on soils. Natural zones are named according to the nature of their vegetation, since it most obviously reflects other features of nature.
The climate naturally changes as it moves from the equator to the poles. Soil, vegetation and fauna are determined by climate. This means that these components should change latitudinally, following climate change. The natural change of natural zones when moving from the equator to the poles is called latitudinal zonality. There are humid equatorial forests near the equator, and icy forests near the poles. arctic deserts. Between them are other types of forests, savannas, deserts, and tundra. Forest zones, as a rule, are located in areas where the ratio of heat and moisture is balanced (equatorial and most of the temperate zone, eastern coasts of continents in the tropical and subtropical zone). Treeless zones form where there is a lack of heat (tundra) or moisture (steppes, deserts). These are continental regions of the tropical and temperate zones, as well as the subarctic climate zone.
The climate changes not only in latitude, but also due to changes in altitude. As you go up the mountains, the temperature drops. Up to an altitude of 2000-3000 m, the amount of precipitation increases. A change in the ratio of heat and moisture causes a change in soil and vegetation cover. Thus, different natural zones are located in the mountains at different altitudes. This pattern is called altitudinal zone.
The change in altitudinal zones in the mountains occurs in approximately the same sequence as on the plains, when moving from the equator to the poles. Located at the foot of the mountains natural area, in which they are located. The number of altitudinal zones is determined by the height of the mountains and their geographical location. The higher the mountains, and the closer they are located to the equator, the more diverse the set of altitudinal zones. Most complete vertical zonality expressed in the Northern Andes. In the foothills there are moist equatorial forests, then there is a belt of mountain forests, and even higher - thickets of bamboo and tree ferns. With an increase in altitude and a decrease in average annual temperatures, coniferous forests appear, which are replaced by mountain meadows, often turning into rocky areas covered with moss and lichens. The peaks of the mountains are crowned with snow and glaciers.
Ice zone
Ice zone occupies the very north of our country and includes the Arctic Ocean and islands. Its southern border runs approximately along the parallel of 71° N. w. Northern position determines severity natural conditions zones; Ice and snow cover lies here almost throughout the year.
Seasons in the ice zone they are very peculiar. in winter The polar night prevails, which is at a latitude of 75° N. w. lasts 98 days, at latitude 80° - 127 days, and in the pole area - six months. At this time, auroras often flash in the sky. At times they illuminate the sky for several days, but more often the radiance lasts an hour and a half.
Summer characterized by bright round-the-clock lighting, but a lack of heat. The air temperature remains very low in summer and rarely rises above 0°. the average temperature of the warmest month does not exceed +5°C. The sky is sometimes overcast with gray low clouds, and for several days there is drizzling rain, turning into snow. Fogs are frequent. There are almost no thunderstorms or showers. Despite the cold summer, the snow cover is open places comes off and the soil on the surface thaws. Before the snow has melted, arctic plants begin to turn green and bloom on the islands: poppies and saxifrage. Bright flowers next to the snow - a common summer picture.
Appear in summer animals, which are almost invisible in winter: polar bear, arctic fox, pied, as well as birds arriving from the south: gulls, guillemots, guillemots, auks, etc. Many birds They make nests on coastal rocks and form so-called bird colonies. Summer is short. In August, the temperature already drops below 0°, the frosts intensify, and snow covers the ground with a continuous blanket. In spring and autumn, for some time there is a change of day and night during the day.
Most of the northern Arctic Ocean covered throughout the year floating ice. Thickness first-year ice reaches 1.8 m, perennial ice - 3-4 m, hummocky ice - up to 20-25 m.
There is almost no permanent population in the ice zone. Weather stations have been built on the islands and the mainland to monitor the weather and ice movement. Observational data is transmitted to Moscow, to the hydrometeorological center, where they are processed and plotted on special maps.
In the central part of the Arctic Ocean, “North Pole” stations are set up, drifting on ice fields. Winterers at these stations study the condition of the ice, take measurements of the seabed, establish the direction of ice drift and carry out many other important scientific observations. The first station was organized in 1937. Since 1975, the North Pole - 23 station has been operating.
On the Arctic islands they hunt Arctic foxes in winter and game birds in summer. There are many different fish in the waters of the Barents Sea, which are caught and processed on special vessels. The base of the trawl fishing fleet is the port of Murmansk.
Tundra zone
Word " tundra" comes from Finnish " tunturi", which means " flat treeless hill" Indeed, the absence of trees is the most striking, eye-catching feature tundra zones.
Tundras are widespread mainly in the Northern Hemisphere - in Eurasia and North America. The tundra zone, an almost continuous belt, stretches across the northernmost territories of the continents around the North Pole, as scientists say, circumpolarly (“circum” in Latin - “around”: remember the round arena of the circus).
In the Southern Hemisphere there is very little land near Antarctica - mostly ocean. Therefore, there are very few tundras there and they are located on small islands around the southern mainland and in the mountains of Patagonia.
The areas occupied by tundra zones are much larger than is commonly believed. In Russia, tundras occupy the second largest area after the taiga (although together with the forest-tundra - the transition zone from it to the forest). In North America, they also occupy vast areas. Along mountain ranges, tundra landscapes in some places extend far to the south, to where on the plain taiga forests have long been replaced by steppes.
With the word " Arctic"usually associated with the idea of severe cold, snowstorms and the lack of "necessary conditions for life. And indeed, such an opinion is not without foundation - after all, summer in the tundra it is cold, short and light. Cold - because even in summer frosts are not uncommon, and the average monthly temperature of the warmest month does not exceed 10 C. Short - because it lasts no more than 2 - 2.5 months. And it’s bright because at this time the sun does not set below the horizon and stays there all day long polar day. In addition, there is very little precipitation in the tundra, no more than in the desert. But it seems like there is a lot of water. There are large and small lakes, rivers, swamps all around, wet moss squelches under your feet. This is due to the fact that the sun, although it does not set beyond the horizon, still heats weakly and evaporates very slowly. In addition, in the summer in the tundra, only the top layer of permafrost thaws, and even then not for long, while the lower, icy layer does not allow water to seep deeper.
The surrounding tundra zone is cold and damp. In such harsh conditions, it is difficult for true soil to develop. All processes proceed sluggishly, as if reluctantly, and the result is appropriate - the soils are only primitive, with barely defined layers, most of which are occupied by the semi-decomposed remains of mosses, grasses and shrubs - peat.
Although the tundra zone is spread over vast areas, the diversity of plant species here is very small. In some areas their number is 200 - 300, and in the north - less than 100. No other landscapes, except desert ones, seem so monotonous. It is interesting that tundra landscapes located far from each other, even at different ends of the continents, have almost the same set of plant species. One explanation for this “unanimity” is that in winter time the fruits and seeds of tundra plants are well dispersed by the wind over snow or ice, crossing land and sea without hindrance.
On the southern border of the tundra zone, small groups of trees are occasionally found. They made a depressing impression on the Russian ethnographer V.L. Seroshevsky: “ This forest is pathetic. Prematurely aged, covered with bearded lichens, with liquid, yellowish greenery on the few living shoots. The trees are sick, ugly, covered with a mass of warts, twigs, and branches. They provide almost no shade or protection at all; in such a forest you see the sky everywhere in front of you».
And yet the tundra can be attractive and understandable to the eye. Imagine the never setting sun, small courageous plants rushing to bloom their dim but numerous flowers, the blue surface of the water. Alas, this beauty is short-lived. Both herbaceous plants and dwarf trees, hardly taller than grasses, are all in a hurry, in a hurry, in a hurry.
They are in a hurry to open the leaves, they are in a hurry to bloom and set seeds, they are in a hurry to drop them - to sow them in the inhospitable frozen soil saturated with water. If they didn’t have time, the frost was merciless, the sun would also disappear for a long time, and life would freeze for many months in anticipation of a new, such a short summer.
Topic 2. Forest zone
Forest- this is a natural (geographical) zone represented by more or less closely growing trees and shrubs of one or more species. The forest has the ability to constantly renew itself.
Mosses, lichens, grasses, and shrubs play a secondary role in the forest. Plants here influence each other, interact with their environment, forming a community of plants.
A significant area of forest with more or less clear boundaries is called a forest area. The following types of forests are distinguished:
Gallery forest. It is stretched out in a narrow strip along the river flowing among treeless spaces (in Central Asia it is called tugai forest, or tugai);
Belt bur. That's what they call it pine forests, growing in the form of a narrow and long strip on the sands. They are of great water conservation importance; their logging is prohibited;
Park forest. This is an array of natural or artificial origin with rare, individually scattered trees (for example, a park forest of stone birch in Kamchatka);
Coppices. These are small forests connecting forest areas; Grove- a section of forest, usually isolated from the main tract.
The forest is characterized by tiers - vertical division of the forest, as if into separate floors. One or more upper tiers form the crowns of trees, then there are tiers of bushes (undergrowth), herbaceous plants and, finally, a layer of mosses and lichens. The lower the tier, the less demanding of light are its components.
kinds. Plants of different tiers interact closely and are mutually dependent. The strong growth of the upper tiers reduces the density of the lower ones, up to their complete disappearance, and vice versa. There is also an underground layering in the soil: the roots of plants are located here at different depths, so numerous plants coexist well in one area. Man, by regulating the density of crops, forces the development of those tiers of the community that are valuable for the economy.
Depending on climatic, soil and other natural conditions, various forests arise.
Equatorial rainforests
This is a natural (geographical) zone stretching along the equator with some displacement south of 8° N latitude. to 11° S The climate is hot and humid. All year round average air temperatures are 24-28 C. Seasons are not defined. At least 1500 mm of precipitation falls, since there is an area of low pressure (see. Atmosphere pressure), and on the coast the amount of precipitation increases to 10,000 mm. Precipitation falls evenly throughout the year.
Such climatic conditions This zone contributes to the development of lush evergreen vegetation with a complex layered forest structure. The trees here have few branches. They have disc-shaped roots, large leathery leaves, tree trunks rise like columns and only spread their thick crown at the top. Shiny, as it were varnished surface leaves saves them from excessive evaporation and burns from the scorching sun, from the impacts of rain jets during heavy downpours. In plants of the lower tier, the leaves, on the contrary, are thin and delicate.
The equatorial forests of South America are called selva (port. - forest). This zone occupies much larger areas here than in Africa. The selva is wetter than African equatorial forests and richer in plant and animal species.
The soils under the forest canopy are red-yellow and ferrolitic (containing aluminum and iron).