1. Most of the land is concentrated in the northern hemisphere - Eurasia, more than half of Africa, North America and part of South America. In the south there remained a small Australia and parts of South America and Africa.
The northern hemisphere turned out to be continental, although here only 39% is land and 61% is ocean, while the southern hemisphere is oceanic. Antarctica, located around South Pole, does not break the continuous oceanic monotony of the southern hemisphere. But even with it, 81% of the southern hemisphere is covered with water.

2. The latitudinal bands of the planetary megarelief of the Earth are clearly visible: a) oceanic subsidence of the northern polar latitudes, b) Laurasian continents of the middle latitudes of the northern hemisphere, c) Gondwanan continents of tropical latitudes, d) the oceanic ring of the middle latitudes of the southern hemisphere and e) continental rise of the southern polar latitudes .
The reasons for this localization of continental blocks have not yet been explained. The theory of mobilism, having explained the origin of the continents from Gondwana and Laurasia and the reasons for their movement, does not address the issue; they lie in these places on the globe.
So far, the only explanation is provided by the rotational regime of the Earth, which creates tectonic inequality of parallel stripes and meridional rays of the rotating planet.

3. The northern continents extend from tropical latitudes through temperate and subpolar latitudes, and are located circumpolarly, while the southern continents do not extend beyond the subtropical ones.

4. In the west-east direction, the continents are arranged in pairs in three rays (it would be more convenient to call them sectors, but this term has entered into geography with a different meaning: it denotes the western, central and eastern regions of the continents): a) both Americas, b) Europe and Africa, c) Asia and Australia.

5. The combination of the latitudinal circumpolar and west-east ray positions of the continents creates a “continental star”.
The “Continental Star” has four rays, but the continents are located only in three rays, they are not in the Pacific. This corresponds to its geological age. The “Continental Star” is first presented as a purely external, only geometric reflection of the location of the continents. In fact, it characterizes the very essence of the planet's megarelief - the zonal-sectoral nature of the distribution of continents and oceans over the surface of the globe.
Spherical functional analysis showed that the degree of manifestation of the “continental star”, i.e. the degree of sectorality in the location of continents and oceans, is proportional to the sine of latitude. It is most pronounced at the equator, at 30° latitude it decreases to 56%, and at 60° to 6.3%, and finally disappears at polar latitudes. The mathematical data corresponds to the actual situation.
Calculations of the heights of the continents for past geological eras give reason to believe that the “continental star” began to form only in the Silurian period. Before this, latitudinal and meridional patterns were probably not evident in the distribution of continents.

6. Calculations of stresses on the surface of the rotating pear-shaped Earth showed that the parallels are 50° N. latitude, 17° S. w. and 90° S. w. and meridians 70° W. d., 20° east. long and 110° east d. form a single planetary grid that controls the position of the continents on Earth.
The centers of gravity of the northern Laurasian continents are located around 44-55° N. sh., in a strip only 11° wide. If we add to this the extensive continental shoals that often connect continents, it becomes clear that there are strong connections between the northern continents; the continental crust is consolidated here. This corresponds to the “continentality” of the 50° N parallel. w.
The southern Gondwanan continents, on the contrary, are quite scattered; their centers of gravity are within 7° N. w. - 22° S latitude, on average 17° S. w. The reason for this, as we have already seen, lies in the regime of the oceanic lithosphere.

7. The eccentricity of the lithosphere, expressing one of the essences of the structure of our planet, shows the historical, geological and geophysical basis of the continentality of the northern and eastern hemispheres and the oceanicity of the southern and western hemispheres.
The lithosphere is eccentric in the meridional (north-south) direction: the continental lithosphere is shifted to the north, and the oceanic lithosphere to the south, one relative to the other and both relative to the center of the planet.
Graphically, eccentricity can be expressed in the form of a diagram of the ratio of land and ocean areas by latitudinal bands.
The meridional eccentricity of the lithosphere is so great that it makes the planet's topography antisymmetric: the continental belt of the northern hemisphere is opposed by the oceanic belt of the southern hemisphere, the Arctic - Antarctica.
The lithosphere is also eccentric in the west-east direction: most of the continental lithosphere is concentrated in the part of the Earth where Gondwanaland and Laurasia were located (eastern hemisphere). The smaller part - two continents are shifted to the west, into the western hemisphere. The reasons for this arrangement probably lie in the patterns of life in the ocean crust.
The expressions Old and New Worlds, which appeared after the discovery of America, now acquire a new, already geological content: in the Old lie the ancestral continents, in the New - daughter formations.

8. Antipodality of continents and oceans. The continents are located in such a way that each of them, at the opposite end of the Earth's diameter, certainly has a corresponding ocean. This is most obvious in the comparison of the Arctic ocean and Antarctic land. But if the globe is installed so that any of the continents is at one of the poles, then there will definitely be an ocean at the other pole. There is only one minor exception: the end of South America and Southeast Asia.
Antipodality, since it has almost no exceptions, cannot be a random phenomenon. It is probably based on the balance of all parts of the surface of the rotating Earth, the rotational reason.
Continental drift, inevitable for endogenous reasons, causes a disruption of the achieved equilibrium; Perhaps this is the reason for the displacement of the pole, which is allowed by many, or more precisely, the movement of the Earth relative to the axis of rotation, inclined to the axis of the World, always at approximately the same angle.

9. Almost all continents have the shape of wedges or triangles, the sharp peaks of which face south. The wedge-shaped shape is characteristic of both Americas and Africa, less typical of Eurasia (the southern apex of the triangle at Cape Kumari in Hindustan) and is absent in Australia. It is obvious that the general shape of the continents, as well as the character coastline, and the size of the continental shelf are determined by the cleavage lines of Gondwana and Laurasia. The proto-continents were generally oval in shape; their fragments, naturally, should be wedge-shaped.

10. Meridional distortion. Meridianally elongated planetary landforms extend in an S-shape. This direction is characteristic of the Cordillera - Andes, Atlantic Ocean, the Mid-Atlantic Ridge, the eastern coast of Asia - all the main orographic formations in the north-south direction.
The meridional distortion of planetary structures was explained from the standpoint of various geophysical and geological constructions. However, there are still no convincing explanations. Of course, it indicates the tectonic inequality of both the northern and southern hemispheres as a whole, and the individual latitudinal bands of each of them.

11. The Earth’s crust is cut latitudally and meridionally by fault belts:
A. Mediterranean. It passes near the orogenic parallel 35° N. w. through the Mediterranean Sea, the system of alpine arcs of North Africa, Southern Europe and Western Asia to the Himalayas and Indochina, as well as through Central America. It is expressed
young mountain ranges, collapsed seas, volcanoes, and seismic areas are confined to it.
B. In the southern hemisphere it is also about 35° S. w. a second fault belt passes through, expressed by the end of the southern continents (in South America - the continental plate; remember that the tip of this continent is antipodal not to the ocean, but to southeast Asia).
B. Along all the shores of the Great Ocean in the meridional direction runs the Pacific Rift Belt, better known as the Pacific Ring of Fire, as it is characterized by strong volcanism and seismicity. This is the area of ​​the youngest orogeny, expressed by island arcs.

The landmass of the globe is fragmented into a number of huge massifs and smaller areas.

Large blocks are called continents, or small islands. The smallest of the continents (Australia, 7.6 million sq. km) is four times larger in area than the largest of the islands (Greenland, 2.2 million sq. km).

There are seven continents. The boundaries between continents are not always clear. In this regard, only Australia and Antarctica are beyond doubt. The Suez and Panama Canals serve as conventional borders - the first between Africa and Asia, the second between North America and South America. But it is especially difficult to draw a line between Europe and Asia, which, in essence, constitute a single continent - Eurasia. Nowadays the Caucasus and Transcaucasia are classified as Europe, and the eastern border of Europe is drawn along Ural mountains, Mugojaram and r. Embe.

Asia is not only the largest continent, but also the highest. It is followed in descending order by average height by: Africa, North America, South America, Europe and Australia. Antarctica stands apart. Its huge average height is explained by the presence of a powerful ice sheet, the thickness of which reaches 1600 m.

Both in the outlines of the continents, and in their grouping, and in the structure of their surface, there are features that have long attracted attention.

All continents, with the exception of Antarctica, are grouped in pairs: North America with South America, Europe with Africa, Asia with Australia. Each pair forms a continental ray, and all rays converge towards the northern polar space, forming the so-called “continental star”, which appears especially clearly on maps constructed in a stellar projection.

In each pair, the northern continent is separated from the southern continent by a fault area earth's crust, characterized by the presence of deep seas, an abundance of islands (fragments of this fragmented crust), frequent and strong earthquakes and intense volcanic activity.

The characteristic shape of the continents is also striking, resembling triangles with their bases facing north. The northern parts of the continents are wide, and to the south the continents seem to wedge out. This is also true for Europe and Asia, if we consider them as something single (Eurasia). The shape of Antarctica is pear-shaped, that is, also generally triangular; the narrow part faces South America.

There are also other features that are not typical, however, of all continents. Thus, each of the southern continents has a concavity in the west (South America has the Gulf of Arica, Africa has the Gulf of Guinea, Australia and Tasmania have the Great Australian Bight), and in the east it has a convexity. Some continents along their eastern edges are framed by garlands of islands, while with west side There are no such garlands. In this case, the island garlands form arcs, sometimes strongly curved, but always convexly facing east: the Arc of the Antilles, the garland of islands connecting South America with Antarctica (South Georgia, South Sandwich, South Orkney, South Shetland), the huge scalloped arc of the East Asian islands (Kuril , Japanese, Philippine), which includes the Aleutian Islands, although they are attached to the American mainland.

The current level of our knowledge does not allow us to go beyond a simple statement of the features outlined above. Attempts to explain all or some of them have been made repeatedly. But none of the proposed explanations is certain. Therefore, we limited ourselves to presenting factual data. Even in this form, knowledge of them makes the idea of ​​the earth’s surface more harmonious and systematized.

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Dimensions. In terms of their size, among all the continents they stand out: Eurasia - the largest in area (52.2 million km 2), which accounts for 37% of the land surface; - the smallest (7.68 million km 2), it is sometimes called the mainland island, it is only 3.4 times larger than the largest island of our planet, Greenland (2.2 million km 2), its territory will fit twice within the borders of Russia (17.07 million km 2). The second largest continent on the planet is Africa (29.2 million km2), within its borders it can accommodate three Europes (9.3 million km2) or Russia along with Canada (9.97 million km2) and Greenland. The third largest continent is North America (20.36 million km2), which is 2.6 times less than the area of ​​Eurasia. Next come South America (18.13 million km2), which is slightly larger than Russia, and Antarctica (12.4 million km2).

In size, all the southern tropical continents (Africa, Australia, South America) are inferior to Eurasia. Even the largest of them, Africa, is almost half the size of Eurasia in area.

In Eurasia there are 2 parts of the world - Europe and Asia. This division has a traditional cultural and historical basis. The idea of ​​Europe and Asia as various parts The concept of light arose in ancient times, much earlier than the formation of geographical ideas about the true size and contours of the entire continent as a whole. Therefore, for a long time there was a concept of Europe and Asia not only as different parts of the world, but also as different continents. In physical-geographical terms, it is purely conditional, just as the border between Europe and Asia is conditional.

Configuration. S.V. Kalesnik, noting the main features of the structure of the earth’s surface, points to the following points:

  1. All continents, except Antarctica, are grouped in pairs: North America with South America, Europe with Africa, Asia with Australia. Each pair forms a "continental ray", and all rays converge towards the north polar space, collectively forming a "continental star". E. Reclus (1868) called this feature the law of three mutually parallel double continents.
  2. All continents have the shape of wedges or triangles, with their bases facing north. The pear-shaped (triangular) shape is also characteristic of Antarctica.
  3. Each of the southern continents has a concavity in the west (Arik, Guinea, Great Australian Gulfs), and a convexity in the east.
  4. In each continental ray, the southern continent is shifted to the east relative to the northern one, and is not a direct meridional continuation of it.

When interpreting the above-mentioned features, we proceed from the nature of the ascending and descending movements in the lithosphere and the processes of compression of the Earth. Thus, in the northern hemisphere, the continents wedge out to the south because secular zonal subsidence of the equatorial belt is superimposed on the meridional continental uplifts (due to a general secular decrease in the polar compression of the Earth). The pinching out of continents in the southern hemisphere is caused by a higher rate of volumetric compression compared to the northern hemisphere.

With the lowering of the masses of the lithosphere of the equatorial belt and, therefore, with their approach to earth's axis, as a result of which they acquire an additional rotation speed, the crescent shape of South America and Africa is associated (the presence in their outlines of concavity in the west and convexity in the east), as well as the clockwise rotation of Australia.

The predominance of lithospheric uplifts in the northern hemisphere and subsidence in the southern is the reason for the displacement of the northern continents to the west, and the southern continents to the east. This is a consequence of the torsion effect under the influence of an additional tangential force arising according to the law of conservation of angular momentum.

A general pattern that is, to one degree or another, inherent in all continents of the Earth: wide in the northern part, they narrow towards the south. Only for the configuration of Eurasia and Australia is this characteristic to a lesser extent, in their form - they are isometric. Both of these continents are more elongated from west to east (Eurasia is 16 thousand km, and Australia is 4100 km) than from north to south (the greatest extent of Eurasia in this direction is 8 thousand km, and Australia is 3200 km).

Both the American continents and Africa are elongated along the meridian: the length of Africa is 20 0 east. – about 68 0 North America at 100 0 W. – about 52 0, South America at 70 0 west. – about 66 0. They are distinguished by the expansion in the northern part and the narrowing of the continent in the south: South America reaches its maximum width (5150 km) at 5-8 0 S latitude. in the south the width of the continent does not exceed 400 km. Africa is characterized by unequal areas north and south of the equator. The northern half of the continent is more than twice as wide as the southern half: from Cape Verde (Cape Almadi) in the west to Cape Ras Hafun in the east, the distance is 7,500 km; the width of the southern half does not exceed 3100 km. North America reaches its greatest size in temperate and polar latitudes, stretching from west to east for 112 0, which corresponds to seven time zones, or 4560 km, along the northern tropic line, within Mexico the distance from Pacific Ocean to the Atlantic does not exceed 10 0 or 1000 km.

Outlines of the coastline. The northern continents (Eurasia and) are distinguished by significantly rugged coastlines. The peninsulas occupy about a quarter of the area of ​​each of them.

The coasts of Eurasia are the most indented. Oceans and seas, going deep into the continent, greatly dissect its outskirts. The western part of Eurasia outside Russia is the narrowest and most deeply dissected by seas, i.e. foreign Europe: 1/3 of its surface is on islands and peninsulas and the greatest distance to the sea is only 600 km. Compared to Europe, Asia is distinguished by its great compactness and solidity. However, islands and peninsulas occupy 24% of its territory.

Let's remember

How is planet Earth different from other planets in the solar system?

We are thinking

Why would it be more logical to call our planet a planet?

Ocean?

A significant part of the surface of the globe is covered with water. Water area -World ocean– occupies 71% of the Earth's surface. The land protrudes above the water - continents and islands. Land accounts for only 29% of the Earth's surface.

Continents- these are huge areas of land, surrounded on all sides (or almost all sides) by water. There are six continents on Earth: Eurasia, Africa, North America, South America, Antarctica, Australia (Figure 1). The largest of the continents isEurasia. It is connected by a small piece of land to the second largest continentAfrica. The third and fourth places in terms of area are occupied byNorth America And South America,they are also connected by a narrow piece of land.Antarctica– the fifth largest continent. It is covered by a thick ice sheet. This is the only continent where people do not live permanently. The smallest continent in the Southern Hemisphere isAustralia.



Figure 1– Continents and oceans

Since ancient times, land has been divided not only into continents, but also intoparts of the world– historically established regions. There are also six parts of the world:Europe, Asia, Africa, America, Antarctica, Australia and Oceania (Figure 2). Parts of the world Europe and Asia are located on the same continent, Eurasia, and the continents of North America and South America form one part of the world - America.

Figure 2– Parts of the world

Along with the continents, the landmass of our planet also consists of islands.Islands- These are small areas of land compared to continents, surrounded on all sides by water. There are a lot of them on Earth. There are single islands and groups of islands lying at a short distance from each other - they are called archipelagos. The largest island on Earth isGreenland. The largest islands also include New Guinea, Kalimantan and Madagascar.

Huge depressions on the surface of the planet are occupied by the waters of the World Ocean. Continents and islands divide it into separate oceans:Pacific, Atlantic, Indian, Arctic . The Pacific Ocean is the largest, occupying almost half the area of ​​the World Ocean. The Atlantic Ocean is half the size of the Pacific Ocean. From north to south it has the same length as the Quiet, and from west to east it is much narrower. The Indian Ocean is the third largest, but its area can accommodate three continents. The Arctic Ocean is the smallest ocean in area, located in the north of the planet.

Let's summarize!

The surface of our planet is made up of land and water – the World Ocean.

The land consists of continents and numerous islands. There are six continents: Eurasia, Africa, North America, South America, Antarctica, Australia. Continents and islands divide the World Ocean into four oceans: the Pacific, Atlantic, Indian and Arctic.

Answer questions, complete tasks

1. What is a continent?

2. How many continents are there on Earth? Name them in order of decreasing area.

3. What do we call the World Ocean?

4. How many oceans are there on Earth? Name them in order of decreasing area.

5. On what continent and in what part of the world is the Republic of Belarus located?

6. What is an island called?

7. What is the name of the largest island on Earth?

Do practical work

"Applying to contour map geographical objects"

1. Using the physical map of the hemispheres, label the outline map:

a) continents;

b) oceans;

c) the largest islands and groups of islands that you found on physical map hemispheres.