Natural zones of the southern continents. Natural areas Why natural areas on the continents are not everywhere

The natural complexes of the Earth are very diverse. These are hot and icy deserts, evergreen forests, endless steppes, bizarre mountains. This diversity is the unique beauty of our planet.

You already know how natural complexes, “continents”, “oceans” were formed. But the nature of each continent, like each ocean, is not the same. Various natural zones are formed on their territory.

Theme: Nature of the Earth

Lesson: natural areas Earth

1. Today we will find out

Why are natural areas formed,

On the patterns of placement of natural zones,

Features of the natural zones of the continents.

2. Formation of natural zones

A natural zone is a natural complex with uniform temperatures, moisture, similar soils, flora and fauna. The natural area is named after the type of vegetation. For example, taiga broadleaf forests.

The main reason for the heterogeneity of the geographic envelope is the uneven redistribution of solar heat on the Earth's surface.

Almost in every climate zone the oceanic parts of the land are more humid than the inland, continental ones. And it depends not only on the amount of precipitation, but also on the ratio of heat and moisture. The warmer it is, the more moisture that has fallen with precipitation evaporates. The same amount of moisture can lead to excess moisture in one zone and insufficient moisture in another.

Rice. 1. Swamp

So, the annual amount of precipitation is 200 mm in the cold subarctic belt- excessive moisture, which leads to the formation of swamps (see Fig. 1).

And in hot tropical zones - sharply insufficient: deserts are formed (see Fig. 2).

Rice. 2. Desert

Due to differences in the amount of solar heat and moisture, natural zones are formed within geographic zones.

3. Patterns of placement

In the placement of natural zones on the earth's surface, a clear pattern is visible, which can be clearly seen on the map of natural zones. They stretch in a latitudinal direction, replacing each other from north to south.

Due to the heterogeneity of the relief of the earth's surface and the conditions of moisture in different parts continents natural zones do not form continuous bands parallel to the equator. More often they are replaced in the direction from the coasts of the oceans to the interior of the continents. In the mountains, natural zones replace each other from the foot to the peaks. This is where altitudinal zonality comes into play.

Natural zones are also formed in the World Ocean: from the equator to the poles, the properties of surface waters, the composition of vegetation and wildlife change.

Rice. 3. Natural areas of the world

4. Features of the natural zones of the continents

In the same natural zones on different continents, plant and animal world have similar features.

However, the characteristics of the distribution of plants and animals, in addition to climate, are also influenced by other factors: the geological history of the continents, relief, 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 live on different continents different types animals and plants.

For example, antelopes, buffaloes, zebras, African ostriches are characteristic of the African savannahs, and several species of deer and a flightless rhea bird similar to an ostrich are common in the South American savannahs.

On each continent there are endemics - both plants and animals, characteristic only of this continent. For example, kangaroos are found only in Australia, and polar bears are found only in the Arctic deserts.

Geofocus

The sun heats the spherical surface of the Earth differently: the areas above which it stands high receive the most heat.

Above the poles, the Sun's rays only glide over the Earth. The climate depends on this: hot at the equator, harsh and cold at the poles. The main features of the distribution of vegetation and fauna are also connected with this.

Moist evergreen forests are located in narrow bands and patches along the equator. "Green Hell" - this is what many travelers of past centuries called these places, who had to be here. High multi-tiered forests stand like a solid wall, under the dense crowns of which dusk, monstrous humidity, constant heat, there is no change of seasons, showers regularly fall in an almost continuous stream of water. The forests of the equator are also called permanent rain forests. The traveler Alexander Humboldt called them "hylaea" (from the Greek hyle - forest). Most likely, this is what the humid forests of the Carboniferous period looked like with giant ferns and horsetails.

The rainforests of South America are called "selva" (see Fig. 4).

Rice. 4. Selva

Savannahs are a sea of ​​grasses with occasional islands of trees with umbrella crowns (see Fig. 5). Vast spaces of these amazing natural communities are found in Africa, although there are savannahs in South America, Australia, and India. Distinctive feature savannah is an alternation of dry and wet seasons, which take about half a year, replacing each other. The fact is that for subtropical and tropical latitudes, where savannahs are located, a change of two different air masses- wet equatorial and dry tropical. Monsoon winds, bringing seasonal rains, significantly affect the climate of the savannahs. Since these landscapes are located between the very humid natural zones of the equatorial forests and the very dry zones of the deserts, they are constantly influenced by both. But moisture is not present long enough in the savannahs for multi-tiered forests to grow there, and arid " winter periods» in 2-3 months they do not allow the savanna to turn into a harsh desert.

Rice. 5. Savannah

The natural zone of the taiga is located in the north of Eurasia and North America(see Fig. 6). On the North American continent, it stretches from west to east for more than 5 thousand km, and in Eurasia, originating on the Scandinavian Peninsula, it spread to the coast Pacific Ocean. The Eurasian taiga is the largest continuous forest zone on Earth. It occupies more than 60% of the territory Russian Federation. The taiga contains huge reserves of wood and supplies a large amount of oxygen to the atmosphere. In the north, the taiga smoothly turns into the forest-tundra, gradually the taiga forests are replaced by light forests, and then by individual groups of trees. The furthest taiga forests enter the forest-tundra along river valleys, which are most protected from strong northern winds. In the south, the taiga also smoothly turns into coniferous-deciduous and broad-leaved forests. For many centuries, humans have interfered with natural landscapes in these areas, so now they are a complex natural and anthropogenic complex.

Rice. 6. Taiga

Under the influence of human activity, the geographical envelope is changing. Swamps are being drained, deserts are being irrigated, forests are disappearing, and so on. Thus, the appearance of natural areas is changing.

Homework

Read § 9. Answer the questions:

What determines the moisture content of an area? How various conditions Humidification affect natural complexes?

Are there natural areas in the ocean?

Bibliography

MainI

1. Geography. Earth and people. Grade 7: Textbook for general education. uch. / A. P. Kuznetsov, L. E. Savelyeva, V. P. Dronov, series "Spheres". – M.: Enlightenment, 2011.

2. Geography. Earth and people. Grade 7: atlas, series "Spheres".

Additional

1. N. A. Maksimov. Behind the pages of a geography textbook. – M.: Enlightenment.

Literature for preparing for the GIA and the Unified State Examination

Remember:

Question: What is a natural complex?

Answer: A natural complex is a relatively homogeneous area of ​​the earth's surface, the unity of which is due to its geographic location, a common history of development and modern similar natural processes. All components of nature interact within the natural complex: Earth's crust with her inherent this place structure, the atmosphere with its properties (the climate characteristic of this place), water, the organic world. As a result, each natural complex is a new integral formation with certain features that distinguish it from others. Natural complexes within the land are commonly called natural territorial complexes (NTCs). On the territory of Africa, large natural complexes - the Sahara, the East African Highlands, the Congo Basin (Equatorial Africa), etc. Formed in the ocean and other water bodies (in a lake, river) - natural aquatic (PAC); natural-anthropogenic landscapes (NAL) are created economic activity man on a natural basis.

Question: What do the terms "latitudinal zonality" and "altitude zonality" mean?

Answer: Altitudinal zonality is a regular change natural complexes in the mountains associated with change climatic conditions in height. The number of altitudinal belts depends on the height of the mountains and their position relative to the equator. The change in altitudinal belts and the order of their placement are similar to the change in natural zones on the plains, although they have some features associated with the nature of the mountains, as well as the existence of altitudinal belts that have no analogues in the plains.

Question: In what form natural component give names to natural areas?

Answer: natural area geographical area) - a land area (part of a geographical zone) with certain conditions of temperature and moisture (the ratio of heat and moisture). It is distinguished by the relative homogeneity of flora and fauna and soils, the regime of precipitation and runoff, and the features of exogenous processes. The change of natural zones on land obeys the laws of latitudinal (geographical) zonality, as a result of which natural zones on the plains regularly replace each other either in the latitudinal direction (from the poles to the equator) or from the oceans deep into the continents. Most zones are named after the predominant type of vegetation (e.g. tundra zone, coniferous forests, savanna zone, etc.).

My geographical research:

Question: Which continent has the largest set of natural areas and which has the smallest?

Answer: The Eurasia mainland has the largest set of natural zones.

The mainland Antarctica has the smallest set of natural zones.

Question: Which continents are close to each other in terms of the set of natural zones?

Answer: In terms of the set of natural zones, the continents of Eurasia and North America are close to each other.

Question: On what continents is the location of natural zones close to latitudinal?

Answer: There are not so many areas in which natural zones have an exactly latitudinal strike, and that they occupy very limited areas on the surface of the Earth. In Eurasia, these areas include East End Russian Plain and West Siberian Plain. On the Ural Range separating them, latitudinal zonality is disturbed by vertical zonality. Within North America, the areas in which natural zones have a strictly latitudinal position are even smaller than in Eurasia: latitudinal zonality is expressed with sufficient distinctness only between 80 and 95 ° W. e. B equatorial Africa areas with zones elongated strictly from west to east are significant, they occupy the western (most) part of the mainland, do not extend to the east beyond 25 ° E. e. In the southern part of the mainland, the areas of zones elongated in longitude extend almost to the tropic. In South America and Australia, there are no areas with a clearly expressed latitudinal zonality; there are only boundaries of zones that are close in strike in longitude (in the southern part of Brazil, Paraguay, and Argentina, as well as in the central part of Australia). So, the location of natural zones in the form of strips elongated strictly from west to east is observed in the following conditions: 1) on the plains, 2) in areas of temperate continentality, remote from advection centers, where the conditions of heat and moisture are close to average latitudinal values, and 3) in areas where the amount of average annual precipitation varies from north to south.

Localities that meet such conditions have a limited distribution on the Earth's surface, and therefore the latitudinal zonality in pure form is relatively rare.

Question: On what continents do natural zones extend close to meridional?

Answer: Remoteness from the oceans and features of the general circulation of the atmosphere are the main reasons for the meridional change of natural zones, in Eurasia, where the land reaches its maximum size, the meridional change of natural zones can be traced especially well.

AT temperate zone the western transport brings moisture relatively evenly to the western coasts. On the eastern coasts - monsoonal circulation (rainy and dry seasons). When moving deep into the forest mainland west coast are replaced by steppes, semi-deserts and deserts. As we approach the east coast, forests reappear, but of a different type.

Questions and tasks:

Question: What determines the moistening of territories. How does moisture affect natural complexes?

Answer: Humidification of territories depends on the amount of precipitation, the ratio of heat and moisture. The warmer it is, the more moisture evaporates.

An equal amount of precipitation in different zones leads to different consequences: for example, 200 ml. precipitation in the cold subarctic zone is excessive (may lead to the formation of swamps), and in the tropical zone it is too insufficient (may lead to the formation of deserts).

Question: Why are the natural zones on the continents not consistently replaced from north to south everywhere?

Answer: The location of natural zones on the continents obeys the law of wide zoning, that is, they change from north to south with an increase in the amount of solar radiation. However, there are significant differences, due to the conditions of atmospheric circulation over the mainland, some natural zones replace each other from west to east (along the meridian), because the eastern and western edges of the mainland are the most humid, and the interior is much drier.

Question: Are there natural complexes in the ocean and why?

Answer: The ocean is divided into natural belts or zones, it is similar to the division according to the principle of latitudinal zonality of natural land zones, only without distinguishing types of climate.

That is, arctic, subarctic, northern and southern temperate, northern and southern subtropical, northern and southern tropical, northern and southern subequatorial, equatorial, subantarctic, antarctic.

In addition, large and smaller natural complexes are distinguished: the largest are oceans, smaller ones are seas, even smaller ones are bays, straits, the smallest are parts of bays, and so on.

In addition, the ocean also has a law altitudinal zonality as on land, which makes it possible to divide the natural complexes of the ocean into littoral complexes ( coastal waters, shallow waters), pelagials (surface waters in the open sea), bathyals (medium deep oceans) and abyssals (the deepest parts of the ocean).

The southern continents include Africa, South America, Australia and Antarctica. Connects their location in the southern hemisphere of the Earth, as well as for the most part hot climate, with the exception of Antarctica. The natural zones of the southern continents have many common features, but the peculiarities of vegetation and fauna determine the geographical zones in which they are located.

Antarctica

It is the southernmost continent, but its entire surface is covered with blocks of ice and snow. Even in summer, the temperature here rarely exceeds 0-5 degrees Celsius. Soils are bound by permafrost, which does not allow vegetation to develop. In the natural zone of the Antarctic deserts, only a meager growth of mosses and lichens can be found. The local fauna is also very poor. Polar bears live here, seals and walruses can be found on the coast, and in summer bird colonies form on the rocks.

Rice. 1. Antarctica is the southernmost continent on the planet.

Africa

Africa is considered to be the hottest continent on Earth. Its distinctive feature is its symmetrical arrangement with respect to the equator. This means that the equatorial line divides the mainland into two identical parts. As a result, Africa is characterized by the presence of several natural zones, including humid equatorial and variable-humid forests, savannahs, tropical deserts, and hardwood forests.

The African continent has the most big desert in the world - Sahara. Despite the apparent lifelessness, here you can still find sparse vegetation and representatives of the animal world, adapted to life in the difficult conditions of the desert.

Australia

Australia is considered the driest continent, so it is not surprising that you will not find lush and diverse vegetation here. There are practically no forests in Australia, but there are many deserts.

Due to the flat relief of the mainland, latitudinal zonality is most pronounced here. Since the main part of the continent is located in tropical latitudes, tropical deserts and semi-deserts prevail here. A much smaller area is occupied by savannahs, humid tropical and subtropical forests.

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Rice. 2. Nature of Australia.

For a long time Australia was in great isolation. This explains the antiquity and originality of the local flora and fauna, whose representatives are mostly endemic - species that live exclusively on this mainland.

South America

This is a unique continent, on which more than half of all tropical and equatorial forests of the planet grow. The climate on the mainland is moderately humid and warm, the temperature difference between the seasons is insignificant.

Rice. 3. Equatorial forests of South America.

Natural zones are located unevenly due to the strong differences between the western and eastern parts of the continent, and are represented by several species:

• selva- rain equatorial forests;
• llanos- zone of savannas and woodlands;
• pampas- steppes of subtropics;
• Patagonia- deserts and semi-deserts;
• temperate forests.

The animal and plant world is mostly represented by endemic species.

The earth's surface and moistening conditions in different parts of the continents natural zones do not form continuous bands parallel to the equator. Only in and on some large plains do they extend in a latitudinal direction, replacing each other from north to south. More often they change in the direction from the coasts of the oceans to the depths of the continents, and sometimes they stretch almost along the meridians.

The location of natural zones on the continents is disturbed by mountains. In the mountains, natural zones replace each other from the foot to the peaks, here altitudinal zonation is manifested.

Natural zones are also formed in: from the equator to the poles, the properties of surface waters, the composition of vegetation and wildlife change. There is also vertical zoning. However, oceanic natural complexes do not have pronounced external differences.

There is a great variety of natural complexes on Earth. However, against the background of this diversity, large parts stand out - natural zones and. This is due to the different ratio of heat and moisture that the earth's surface receives.

Formation of natural zones

The uneven distribution of solar heat over the Earth's surface is the main reason for the heterogeneity of the geographic envelope. In almost every land area, the oceanic parts are better moistened than the inland, continental regions. Humidification depends not only on the amount of precipitation, but also on the ratio of heat and moisture. The warmer it is, the more moisture that has fallen with precipitation evaporates. The same amount of precipitation can lead to excessive moisture in one zone and insufficient moisture in another. Thus, the annual precipitation of 200 mm in the cold subarctic zone is excessive (bogs are formed), while in the hot tropical zones it is sharply insufficient (there are deserts).

Due to differences in the amount of solar heat and moisture within geographic zones, natural zones are formed - large areas with uniform temperature and moisture conditions, surface and groundwater features, similar soils, and wildlife.

Features of the natural zones of the continents

In the same natural areas on different continents, vegetation and fauna have similar features.

At the same time, other factors, in addition to climate, also influence the features of the distribution of plants and animals: the geological history of the continents, 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 have led to the fact that in similar natural conditions, but on different continents, different species of plants and animals live. The African savannahs, for example, are characterized by antelopes, buffaloes, zebras, African ostriches, and in the South American savannahs, several species of deer, armadillos and an ostrich-like flightless nandu bird are common. Found on every continent endemic species(endemic), peculiar only to this mainland.

Under the influence of human activity, the geographic envelope is undergoing significant changes. To preserve representatives of the organic world and typical natural complexes in all natural zones of the world, specially protected areas are created -, reserves, etc. national parks, unlike nature reserves, nature protection is combined with tourism and recreation of people.