The mainland is a significant land mass, washed by seas and oceans. In tectonics, continents are characterized as areas of the lithosphere with a continental structure.
Mainland, continent or part of the world? What is the difference?
In geography, another term is often used for the mainland - the continent. But the concepts "mainland" and "continent" are not synonyms. Different countries have adopted different points of view on the number of continents, called continental models.
There are several such models:
- In China, India, as well as in the English-speaking countries of Europe, it is generally accepted that they consider the 7 continents - Europe and Asia separately;
- In Spanish-speaking European countries, as well as in South American countries, they mean division into 6 parts of the world - with a united America;
- in Greece and some countries of Eastern Europe, a model with 5 continents is adopted - only those where people live, i.e. except Antarctica;
- in Russia and the neighboring countries of Eurasia, they traditionally designate 4 - united in large groups, continents.
(The figure clearly shows different representations of continental models on Earth, from 7 to 4)
Continents
There are 6 continents on Earth. Let's list them in descending order by the size of the area:
- - the largest continent on our planet (54.6 million sq. Km)
- (30.3 million sq. Km)
- (24.4 million sq. Km)
- (17.8 million sq. Km)
- (14.1 million sq. Km)
- (7.7 million sq. Km)
They are all separated by the waters of the seas and oceans. Four continents have a land border: Eurasia and Africa are separated by the Isthmus of Suez, North and South America - by the Isthmus of Panama.
Continents
The difference is that the continents do not have a land border. Therefore, in this case, we can talk about 4 continents ( one of the continental models of the world), also in descending order of size:
- AfroEurasia
- America
Parts of the world
The terms "mainland" and "continent" have a scientific meaning, but the term "part of the world" divides the land on a historical and cultural basis. There are 6 parts of the world, only, unlike the continents, Eurasia differs by Europe and Asia, but North and South America are defined together as one part of the world America:
- Europe
- Asia
- America (both North and South), or New World
- Australia and Oceania
When talking about parts of the world, they mean the islands adjacent to them.
The difference between the mainland and the island
The definition of the mainland and the island is the same - part of the land, washed by the waters of the ocean or seas. But there are significant differences.
1. Size... Even the smallest mainland, Australia, is significantly larger than the world's largest island, Greenland.
(Formation of the Earth's continents, a single continent of Pangea)
2. Education... All continents are of tiled origin. According to scientists, there was once a single continent - Pangea. Then, as a result of the split, 2 continents appeared - Gondwana and Laurasia, which later split into 6 more parts. The theory is confirmed by both geological surveys and the shape of the continents. Many of them can be put together like a jigsaw puzzle.
Islands are formed in different ways. There are those that, like the continents, are located on the fragments of the oldest lithospheric plates. Others are formed from volcanic lava. Still others are due to the activity of polyps (coral islands).
3. Habitability... All continents are inhabited, even Antarctica, which is harsh in terms of climatic conditions. Many islands still remain uninhabited.
Characteristics of the continents
- the largest continent, occupying 1/3 of the land. There are two parts of the world at once: Europe and Asia. The border between them runs along the line of the Ural Mountains, the Black and Azov Seas, as well as the straits connecting the Black and Mediterranean Seas.
This is the only continent that is washed by all the oceans. The coastline is indented, it forms a large number of bays, peninsulas, islands. The mainland itself is located on six tectonic platforms at once, and therefore the relief of Eurasia is incredibly diverse.
Here are the most extensive plains, the highest mountains (Himalayas with Mount Everest), the deepest lake (Baikal). This is the only continent where all climatic zones (and, accordingly, all natural zones) are represented at once - from the arctic with its permafrost to the equatorial with its sultry deserts and jungles.
¾ of the world's population lives on the mainland, 108 states are located here, of which 94 have the status of independent ones.
- the hottest continent on Earth. It is located on an ancient platform, so most of the area is occupied by plains, mountains are formed along the edges of the mainland. Africa is home to the longest river in the world, the Nile, and the largest desert, the Sahara. The types of climate represented on the mainland are: equatorial, subequatorial, tropical and subtropical.
Africa is usually divided into five regions: North, South, West, East and Central. There are 62 countries on the mainland.
It is washed by the waters of the Pacific, Atlantic and Arctic oceans. The result of the movement of tectonic plates has become a highly indented coastline of the mainland, with a huge number of bays, straits, bays and islands. The largest island is in the north (Greenland).
The Cordillera Mountains stretch along the west coast, and the Appalachians along the east coast. The central part is occupied by a vast plain.
All climatic zones, except for the equatorial one, are represented here, which determines the diversity of natural zones. Most of the rivers and lakes are located in the northern part. The largest river is the Mississippi.
The indigenous population is Indians and Eskimos. Currently, 23 states are located here, of which only three (Canada, USA and Mexico) are on the mainland itself, the rest are on the islands.
It is washed by the Pacific and Atlantic oceans. The longest mountain system in the world stretches along the west coast - the Andes, or the South American Cordilleras. The rest of the mainland is occupied by plateaus, plains and lowlands.
This is the rainiest continent, as most of it is located in the equator zone. Here is the largest and most abundant river in the world - the Amazon.
The indigenous population is Indians. Currently, there are 12 independent states on the mainland.
- the only continent on the territory of which only 1 state is located - the Australian Union. Most of the mainland is occupied by plains, mountains are located only along the coast.
Australia is a unique continent with the largest number of animals and plants - endemic. The indigenous population is the Australian aborigines, or Bushmen.
- the southernmost continent, completely covered with ice. The average thickness of the ice cover is 1600 meters, the largest is 4000 meters. If the ice in Antarctica melted, the sea level would immediately rise by 60 meters!
Most of the mainland is occupied by an icy desert, life glimmers only on the coasts. Antarctica is also the coldest continent. In winter, temperatures can drop below -80 ºC (record -89.2 ºC), in summer - down to -20 ºC.
Australia is the smallest continent on the globe, located in the southern hemisphere. Australia's area with islands is less than 8 million square meters. km, population - about 23 million people.
The western and southern coasts of the mainland are washed by the Indian Ocean, the northern ones are the Timor and Arafur Seas of the Indian Ocean, the eastern ones are the Coral and Tasman seas of the Pacific Ocean. The extreme points of Australia: in the north - Cape York, in the west - Cape Steep Point, in the south - Cape Southeast, in the east - Cape Byron. The distance from the northernmost to the southernmost points of the mainland is 3200 km, from the western to the eastern - 4100 km. Parallel to the eastern coast, the Great Barrier Reef stretches for 2300 km.
The coast of the mainland is poorly indented. There are large bays of Great Australian in the south and Carpentaria in the north. The northern part of Australia has two of the largest peninsulas, Cape York and Arnhemland. This continent includes the adjacent islands - Tasmania, Melville, Kangaroo, etc.
The mainland lies on the ancient Australian plate, which merges into the East Australian fold belt. The average height of Australia is 215 m above sea level, and most of the mainland is occupied by plains and up to 95% of the territory is below 600 m. In the eastern part of the mainland along the coast, the Great Dividing Range stretches, which includes several flat-topped mountain systems. In the western part of the continent there is a plateau up to 500 m high with mesas and ridges, in the central part there is a lowland with a large Lake Eyre. On the territory of the mainland there are deposits of minerals such as coal and brown coal, copper, iron ore, bauxite, titanium, polymetallic and uranium ores, diamonds, gold, natural gas, oil.
The main part of Australia's territory is located in the tropical climatic zone, the northern regions - in the equatorial zone (with a hot climate and frequent summer rains), the southern - in the subtropics (with a predominance of precipitation in winter). In the middle of the continent, 70% of the territory is dominated by a desert and semi-desert climate. The east coast has a hot tropical maritime climate with rainfall in the summer. Average annual precipitation decreases from east to west.
Large river systems of the mainland - Murray, Darling, Flinders. A characteristic feature of Australia is the presence of screams - rivers that fill with water only after heavy rains.
On the vast interior spaces of the mainland are the Great Gibson Desert, Victoria, Great Sandy Desert, etc. Salt lakes can often be seen here. Around the deserts there is a belt of semi-deserts with bushes. In the northern, eastern and southeastern regions of the semi-desert are replaced by savannas. In the mountainous areas and along the coast, forests of palms, tree ferns and eucalyptus grow. Among the wild animals in Australia, there are large numbers of rabbits, pigs, and wild dogs. Among the endemic animals there are many marsupial forms (kangaroos, wombats, marsupial wolves, marsupial moles).
The entire territory of the mainland and the island of Tasmania is occupied by the country of the Australian Union. The state is divided into six states: Victoria, New South Wales, Queensland, Western Australia, South Australia, Tasmania. The indigenous population is only 2% of the total population, the rest of the inhabitants are descendants of Europeans and Asians who colonized the mainland after its discovery in the 17th century. The high level of development of agriculture and mining industry has brought the country to a leading position as a supplier of wheat, coal, gold, iron ore to the world market.
Remember how important water is for other components of nature and for humans. What properties does water have? Which ones are geographically significant? What water bodies are terrestrial waters?
Distribution of inland waters of the land. Waters are distributed extremely unevenly across the continents. There are areas where there is an abundance of rivers, lakes, there are vast swamps, and in some areas there is practically no surface water, except for rare drying up lakes. Of all the continents, South America is the wettest (water-supplied) one. If all the waters flowing down from this continent in a year are distributed in an even layer over its area, then a layer of water with a thickness of more than 500 mm will turn out. This quantity is called the runoff layer (8.1). In Antarctica, almost all water is in solid form, and does not flow into the ocean, but falls in large blocks, forming icebergs. But in terms of the volume of fresh water, Antarctica is many times larger than all continents taken together. It is estimated that the reserves of fresh water contained in the Antarctic ice are approximately equal to the runoff of all rivers on Earth in more than 500 years.
The distribution of inland waters across continents is most dependent on climate, but other factors are also important. The distribution of rivers, lakes, bogs, glaciers, the shape of river valleys and lake basins, and the conditions for the occurrence of groundwater are influenced by the relief and geological structure of the area. For example, even with a low amount of precipitation, swamps can arise if the terrain is flat and it is difficult to drain from it.
All types of inland waters play a huge role in nature and in human life. However, the most prominent place is occupied by rivers.
Rivers. On all continents of the Earth, except for Antarctica, there are large and small river systems. South America has the most ramified river network, receiving the most precipitation.
There are almost no territories on this continent without rivers. The huge basins of the Amazon, Orinoco, Parana occupy most of the mainland (8.2). Most of the rivers originate in the mountains, cut through mountain ranges and high plateaus and plateaus, forming rapids and waterfalls. Then they go out onto flat plains, spread widely, and turn into a dense network of waterways. Material carried by rivers from high places fills the depressions of the earth's crust. Amazonian, Orinokskaya, Laplatskaya lowlands are vast flat plains, composed of river sediments.
The river network of North America has a similar structure. Here, the areas of drainless areas are also small. Many rivers carry water to the Atlantic Ocean and the Gulf of Mexico. The largest of these is the Mississippi system, which collects water from the Cordilleras, the Appalachians, and the American plains (8.3). Rough rivers flow into the Pacific Ocean, cutting through the Cordillera. The Mackenzie River, which has an extensive network of tributaries, flows into the Arctic Ocean. Short, deep, rapids flow into Hudson Bay.
LESSON 33. SOUTH AMERICA SUSHI WATERS. LARGEST RIVER SYSTEMS
Educational goal: to acquaint with the general features of the continental land waters, the main river systems; promote understanding of the influence of climate and relief on the formation and distribution of land waters; improve the skills and abilities to characterize the largest river systems of the mainland.
Equipment: physical map of South America, textbooks, atlases, contour maps.
Basic concepts: land waters, river basins, river system, regime, power supply, waterfall, tectonic lake, lagoon-lake, glacier, groundwater.
Lesson type: learning new material.
II. Updating basic knowledge and skills
Complete the sentences.
South America is located in climatic zones: equatorial ...
The amount of precipitation falling on the east coast is about ...
A special type of climate that forms in the Andes is called ...
The inland waters of the mainland include: rivers ...
The deepest river in the world, located in South America, is called ...
III. Motivation of educational and cognitive activities
The well-known idea is: "The water network of the continent is a mirror of its climate and relief." Do you agree with him? Today in the lesson, studying the inland waters of South America, you have the opportunity to confirm or deny this statement.
IV. Learning new material
1. General characteristics of the inland waters of South America
South America ranks first in terms of water supply. The continent covers about 12% of the land area, but accounts for 27% of the total world water flow. This is primarily due to the extremely humid climate. Large river systems were formed here. The overwhelming majority of them belong to the Atlantic Ocean basin. The most powerful rivers are the Amazon, Parana, San Francisco, Orinoco.
Most rivers are fed by rain, only some rivers receive water due to the melting of snow and ice in the mountains. Flowing in the Andes, crossing the plateau, the rivers of South America form numerous rapids and waterfalls. On one of the tributaries of the Orinoco River there is the highest waterfall in the world - Angel (1054 m), and on the tributary of the Parana there is a powerful waterfall - Iguazu (72 m).
There are relatively few lakes in South America. The largest lake on the mainland is the tectonic lake-lagoon Maracaibo. In the Central Andes, in a depression at an altitude of 3812 m, there is the largest of the alpine lakes in the world - Titicaca. Extensive swamps form on well-watered lowlands. Large parts of the mainland are well supplied with groundwater, which is of great importance for the water supply of cities.
There are few mountain glaciers in the Andes. As you move south, the height of the snow line gradually decreases.
Student speeches with messages.
2. The largest river systems
Draw up a brief description of the rivers of South America according to the plan. Format the results in a table:
Name |
Leak location |
Direction of flow |
The nature of the flow |
Where does |
1. Amazon |
||||
3. Orinoco |
The Amazon (6516 km) is the deepest river in the world, it has the largest river basin in the world (its area is equal to the area of \u200b\u200bthe whole of Australia). It originates in the Peruvian Andes from its main source - the Maranoin River. After the confluence with Ucayali, the river receives the name Amazon. In terms of length, the Amazon is second only to the Nile. It has as much water as Congo, Mississippi, Yangtze and Obi combined. The Amazon has more than 1,100 tributaries, 20 of which range in length from 1,500 to 3,500 km. More than a hundred tributaries of the Amazon are navigable. Thanks to its numerous tributaries, the Amazon remains full year round.
Other large rivers in South America - Parana and Orinoco, in contrast to the Amazon, have a pronounced seasonal flow. The maximum rise in water level occurs in the summer season, and in the dry period they become very shallow. With the arrival of humid equatorial air, the rainy season sets in, rivers overflow, flooding vast areas and turning them into swamps. Such floods are often catastrophic.
The rivers of the Parana system collect water on the Brazilian plateau and the inner plains, the Orinoco river with its tributaries - on the Evian plateau. In the upper reaches, these rivers are rapids and form numerous waterfalls. In the middle and lower reaches of the Parana and Orinoco rivers, typical lowland rivers are convenient for navigation.
The rivers of South America have significant hydro potential; in the arid regions of the inner plains, river water is used to irrigate fields.
V. Consolidation of the studied material
What are the reasons for the high rate of river flow in South America?
To whose ocean basin most of the rivers of South America belong? How can this be explained?
What type of food is typical for most rivers on the mainland?
What is the origin of the lakes of South America? In what areas are the largest of them located?
What do the river systems of South America and Africa have in common? What makes them different?
Why is the process of glaciation in the Andes not widely spread?
V I. Lesson summary
V II. Homework
Work through paragraph ...
Practical work 8 (continued). Draw major rivers and lakes in South America on a contour map.
Advance (individual students): prepare reports on the natural areas of South America, individual animals and plants, changes in natural complexes by humans.
Measuring the length of rivers is not an easy task, which, however, has been greatly simplified since the advent of artificial satellites. But even with the help of images from space, it is not possible to determine the exact length of the river. Difficulties in identifying the beginning of a river can occur due to the large number of tributaries. Of all the tributaries, the one that begins at the farthest point from the mouth is considered the beginning of the river, giving the river a total total length, while the name of this tributary usually does not coincide with the name of the river. It can also be difficult to determine where the river ends because the mouth of a river is often an estuary that gradually widens and opens into the ocean.
Estuary (from Latin aestuarium - flooded estuary) - one-armed, funnel-shaped mouth of the river, expanding towards the sea. You can think of an estuary as a place where the sea is wedged into the mainland / island due to the washing out of rocks.
Seasonal changes also contribute to the complexity of calculating the total length of river systems. This list shows the lengths of river systems, that is, rivers taking into account their longest tributaries.
10. Congo - Lualaba - Louvois - Luapula - Chambeshi
Congo is a river in Central Africa that flows into the Atlantic Ocean. The length of the Congo - Lualaba - Louvois - Luapula - Chambeshi river system is 4,700 km (the length of the Congo is 4,374 km). It is the deepest and second longest river in Africa, the second largest river in the world after the Amazon.
The width of the river is on average 1.5-2 km, but in some places it reaches 25 km. The depth of the river reaches 230 m - this is the deepest river in the world.
The Congo is the only major river that crosses the equator twice.
9. Cupid - Argun - Turbid channel - Kerulen
Amur is a river in the Far East in East Asia. It flows through the territory of Russia and the border of Russia and China, flowing into the Sea of \u200b\u200bOkhotsk. The length of the Amur - Argun - Mutnaya Channel - Kerulen river system is 5052 km. Amur length - 2824 km
8. Lena - Vitim
Lena - a river in Russia, the largest river in eastern Siberia, flows into the Laptev Sea. The length of the Lena-Vitim river system is 5100 km. Lena's length is 4400 km. The river flows through the territory of the Irkutsk region and Yakutia, some of its tributaries belong to the Transbaikal, Krasnoyarsk, Khabarovsk territories, Buryatia and the Amur region. Lena is the largest of the Russian rivers, whose basin lies entirely within the country. It freezes in the reverse order of opening - from lower reaches to upper reaches.
7. Ob - Irtysh
Ob is a river in Western Siberia. Formed in Altai at the confluence of Biya and Katun. The length of the Ob is 3650 km. At the mouth, it forms the Gulf of Ob and flows into the Kara Sea.
Irtysh is a river in China, Kazakhstan and Russia, left, main, tributary of the Ob. The length of the Irtysh is 4248 km, which exceeds the length of the Ob itself. The Irtysh, together with the Ob, is the longest watercourse in Russia, the second longest in Asia and the seventh in the world (5410 km).
Irtysh is the longest tributary river in the world
6. Yellow River
The Yellow River is a river in China, one of the largest rivers in Asia. The length of the river is 5464 km. The Yellow River originates in the eastern part of the Tibetan Plateau at an altitude of over 4000 m, flows through the lakes Orin-Nur and Jarin-Nur, the spurs of the Kunlun and Nanshan mountain ranges. At the intersection of the Ordos and the Loess Plateau, in its middle reaches, it forms a large bend, then through the gorges of the Shanxi Mountains it enters the Great China Plain, along which it flows about 700 km before the confluence of the Yellow Sea into the Bohai Bay, forming a delta in the confluence area.
Translated from the Chinese language, its name is "Yellow River", which is associated with the abundance of sediments that give a yellowish tint to its waters. It is thanks to them that the sea into which the river flows is called Yellow.
Yellow River - Yellow River
5. Yenisei - Angara - Selenga - Ider
The Yenisei is a river in Siberia, one of the greatest rivers in the world and in Russia. It flows into the Kara Sea of \u200b\u200bthe Arctic Ocean. Length - 3487 km. The length of the waterway: Ider - Selenga - Lake Baikal - Angara - Yenisei is 5550 km.
Angara is a river in Eastern Siberia, the largest right tributary of the Yenisei, the only river flowing from Lake Baikal. It flows through the territory of the Irkutsk region and the Krasnoyarsk region of Russia. Length - 1779 km.
4. Mississippi - Missouri - Jefferson
The Mississippi is the main river of the largest river system in North America. The source is located in Minnesota. The river mainly flows in a southerly direction and reaches a length of 3,770 kilometers, ending in a vast delta in the Gulf of Mexico.
Missouri is a river in the United States, the largest tributary of the Mississippi. The length of the river is 3767 km. It originates in the Rocky Mountains and flows mainly in an east and southeast direction. It flows into the Mississippi near the city of St. Louis.
The length of the Mississippi - Missouri - Jefferson river system is 6275 km.
3. Yangtze
The Yangtze is the longest and most abundant river in Eurasia, the third river in the world in terms of abundance and length. It flows through the territory of China, has a length of about 6300 km, the basin area is 1 808 500 km².
2. Neil
The Nile is a river in Africa, one of the two longest rivers in the world.
The river originates in the East African Plateau and flows into the Mediterranean Sea, forming a delta. In the upper reaches, it receives large tributaries - Bahr el-Ghazal (left) and Achva, Sobat, Blue Nile and Atbara (right). Below the mouth of the right tributary of the Atbara, the Nile flows through a semi-desert, having no tributaries for the last 3120 km.
For a long time, the water system of the Nile was considered the longest on Earth. For 2013, it is established that the Amazon has the longest river system. Its length is 6992 kilometers, while the length of the Nile system is 6852 kilometers.
Feluca is a small decked vessel with peculiar oblique sails in the form of a trapezoid or a triangle clipped from one corner.
1. Amazon
The Amazon is a river in South America, the largest in the world in terms of basin size, water flow and length of the river system. It is formed by the confluence of the Marañon and Ucayali rivers. The length from the main source of Marañon is 6992 km, from the source of Apacheta opened at the end of the 20th century - about 7000 km, from the source of Ucayali over 7000 km.
However, there are long rivers not only on the ground, but also under it. Hamza is the unofficial name for an underground current under the Amazon bed. The opening of the "river" was announced in 2011. The unofficial name is given in honor of the Indian scientist Wali Hamza, who has been researching the Amazon for over 45 years. Hamza flows at a depth of about 4 km underground through porous soils parallel to the Amazon. The length of the "river" is about 6,000 km. According to preliminary calculations, the width of Hamza is about 400 km. The speed of the Khamza current is only a few meters per year - it is even slower than the glaciers move, so it can be called a river rather conditionally. Hamza flows into the Atlantic Ocean at great depths. The water of the Khamza River has a high level of salinity.
20 longest rivers, excluding tributary lengths
- Amazon - 6992 km
- Nile - 6852 km
- Yangtze - 6300 km
- Yellow River hotels - 5464 km
- Mekong - 4500 km
- Lena - 4400 km
- Parana - 4380 km
- Congo - 4374 km
- Irtysh - 4248 km
- Mackenzie hotels - 4241 km
- Niger - 4180 km
- Missouri - 3767 km
- Mississippi - 3734 km
- Ob - 3650 km
- Volga - 3530 km
- Yenisei - 3487 km
- Madeira hotels - 3230 km
- Purus - 3200 km
- Indus - 3180 km
- Yukon -3100 km