Introduction:
The continent of Europe is a cluster of peninsulas and islands that extends North-West of Asia. Amongst the seven continents of the world, Europe ranks sixth in area.
It occupies about 7% of the land surface of the earth but it has about 15% of the world’s total population. It is important because it is centrally placed in the Northern hemisphere, midway between the Old and the New World.
It has helped in the growth of trade between a number of countries. It is a sub-continent of plains and mountains and a variety of resources. So, Europe’ is the most favorable continent for mankind.
Europe has been called the “most active of the continents” on account of the large volume of its trade and industry and its density of population.
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Location:
The continent of Europe (mainland) extends approximately from 35°N latitude (Cape Tarifa of Spain) in the south to 71°N latitude (North Cape of Norway) in the north and from 9°30′ West longitude (Cape Roca) in the west to 65° east longitude (the Ural mountain) in the east.
Thus, Europe covers about 75° longitudes in the east-west and about 35° latitudes in north-south extensions. The island of Iceland, however near the Arctic Circle, is found at 20°W longitude.
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Boundary:
Europe is bounded by the Arctic Ocean, White Sea, and Baltic Sea on the north, the Atlantic Ocean on the west, and the Mediterranean Sea and the Black Sea on the south. On the east, there is a landmass, that the term ‘Eurasia’ is often applied where the continent of Europe merges into Asia and it has no well-defined boundary.
In the absence of better boundaries, the Ural mountains, the Ural River, the Caspian Sea, and the Caucasus mountains may be taken as the eastern limit of Europe. On its three sides-north, south, and west, Europe is bordered by water bodies. In fact, this continent forms a great western peninsula of Asia.
Area and Extension:
Europe is the sixth largest continent in the world. It covers an area of about 10,400,000 square kilometers. It is three and a half times the size of India. The mainland of Europe is about 5760 km from east to west and 3840 km from north to south.
Population:
Though small in size, Europe is the third largest populated continent in the world. Its population is more than 750 million which contributes about 15 per cent to the world’s total population.
Europe is a very small continent, but it consists of about 54 countries. Most of the countries are small in size but very important. In the north are countries like Iceland, Norway, Sweden, and Denmark which are known as ‘Scandinavian countries’.
The Soviet Union (U.S.S.R.) was the largest country in Europe (before 1991). Now it has been divided into 15 independent republics.
Of these, nine republics and a large part of Russia are a part and parcel of Europe, and three of these 15 republics of former U.S.S.R., normally Estonia, Latvia, and Lithuania are. known as Baltic states.
Serbia and Montenegro, Bulgaria, Greece, Romania, Bosnia-Herzegovina, Macedonia, and Albania are known as Balkan states. Greece and Italy are famous for their ancient civilizations.
A small and independent city-state called the Vatican is the seat of the Pope and the headquarters of the Roman Catholic Church. San Marino is the smallest democratic republic state in the world.
Europe is the sixth largest or second smallest (after Oceania) continent in the world. It consists of about 54 countries. Most of the countries are small but very important.
Considering its development in science and technology, agriculture and industry, education and culture, trade and commerce, there is no doubt about Europe’s foremost position amongst the continents of the world. Several geographical factors have contributed to this. These favorable factors are as follows:
1. Central position of Europe in the Northern Hemisphere:
Of all the continents Europe is the most centrally located. So, it has easy access to the shores of Africa, Asia, America, and even further Oceania by sea.
2. Nearness to the Seas or Maritime location of Europe:
The continent of Europe enjoys the influence of inland seas, deep bays, and gulfs; so no part of it, except Russia is more than 650 km, from the sea. The seas, bays and gulfs have not only provided ideal sites for fishing but have made the people of Europe sea-minded.
They encouraged the discovery of unknown lands and trade routes. They have affected the life of the people of the world with their ideals, movements, and inventions. As such for centuries Europe occupied a unique position in the world.
3. Broken Coastline Of Europe:
Considering its size, the continent of Europe has the longest coastline of 38,400 km as compared to all the other continents. The coastlines of Europe are irregular and broken in most places which favors the development of a maximum number of modern ports in the world.
World-famous ports like London, Rotterdam, Genoa, and Marseilles are important.
4. Temperate Climate of Europe:
Europe is the only great landmass that lies almost entirely within the temperate zone. So, here the cool temperate climate enables people to work for long hours.
5. Extensive fertile plains:
Europe has extensive fertile plains and it has the greatest proportion of agricultural land and habitable land than any other continent. There are no large deserts in the whole continent, except for the cold desert of Tundra in its northernmost part.
6. Water Resource:
Numerous navigable rivers are flowing in different parts of Europe. These rivers supply drinking water, irrigation water, and industrial water also.
7. Forest Resource:
Europe is endowed with coniferous forests. Extensive coniferous forests of pine, fir, and birch trees have helped in the tremendous growth of paper and ship-building industries in Europe.
8. Mineral Resource:
Europe is enriched in different types of minerals. The important minerals are petroleum, coal and iron ore.
9. Agricultural Resource:
Europe is highly developed in agriculture. Agriculture in Europe is highly mechanized. Important cereals are wheat, barley, maize, oat, and sugar beet, vegetables and flowers are also grown here. Ukraine is popularly called the “Granary of Europe”.
10. Animal Resource:
Europe is famous for animal products. Russia, Ukraine, Denmark, Netherlands, Germany, the U.K., and France practice cattle and sheep rearing on rich pastures by applying modern techniques. So, milk and milk products, meat, and wool are produced on a commercial basis in Europe.
11. Developed Fishing grounds:
The continental shelf of northwest Europe is famous for fishing grounds. So, countries like Iceland, Norway, U: K., Denmark, Germany, and France are famous for commercial fishing.
The world’s most skilled fishermen are found in Iceland and Norway is called the “Land of Fishermen”.
12. Industrial Development:
Europe is the home of the ‘Industrial Revolution’ and presently the most industrialized part of the world. Most of the important industrial regions of the world namely, Ruhr industrial region, Moscow industrial region, London Basin, Paris Basin, and Donets industrial region are located in Europe.
13. Preservance and Resourcefulness of the people:
The people living on this continent are energetic, enterprising, and progressive. Europe’s economy, ruined twice by world wars recovered mainly due to the sheer presence and resourcefulness of its people.
So, the favorable physical environment and the most dynamic working ability of the Europeans have made this continent geographically very much important in the whole world.
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Relief:
Europe is a very small continent but physiographically it is very much diversified. Though the greater part of the continent is plain land, it also has high plateaus, mountains and very low-lying areas.
Generally, the continent can be divided into the following four distinct physiographic divisions, namely-
The north-western part of Europe is a region of highlands. Mountainous lands of Scandinavia (Norway and Sweden). Finland, the highlands of the north-central U.K., and the northern mountains of Ireland are included in this region.
Physiographic characteristics of this region are as follows:
These plains extend from the Ural mountains in the east to the Bay of Biscay in the west and are located to the south of the north-western highlands. Southern parts of the U.K., Northern France, Netherlands, Belgium, Poland, Northern Germany, and Western Russia are included in this region.
Physiographic characteristics of this region are as follows:
To the south of the Great Plains of Europe, lies the Central Plateau Region and Uplands of Europe. It comprises the Meseta of Spain, the Central Plateau of France, the Rhine highlands, the Bohemian plateau along the Germany-Czech Republic .boundary, and the islands of Sardinia and Corsica.
The physiographic characteristics of this region are as follows.
To the south of the central Plateaus and Uplands, there are several ranges of young fold mountains running parallel to one another from the Atlantic Ocean in the west to the Caspian Sea in the east. It covers most parts of southern Europe in Spain, France, Germany, Switzerland, Italy, Greece, Bulgaria, and Romania.
Physiographic characteristics of this region are as follows:
The fertile plains enclosed by these mountains are. the plain of Lombardy or the Po Valley and the Hungarian and Wallachian Plains of the Danube. The southern fringe of Europe is a region of broken mountain chains, peninsulas, and islands.
Volcanoes:
The recent uplift of the Alps has made this Mediterranean belt unstable. So, this belt is prone to earthquakes and volcanicity. Many volcanoes exist in the northwestern and in southern parts of Europe. These are-Crafla and Hekla in north-western Europe.
Etna(3323 m) on Sicily Island, Vesuvius (1227 m) in Italy, and Stromboli on Lipari Island are located in southern Europe. “Stromboli” is called the ‘Lighthouse of the Mediterranean’ which erupts nearly every hour.
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The continent of Europe has many rivers. These rivers are important resources in Europe. The specific characteristic features of these rivers are as follows:
Important Rivers Of Europe
According to their direction of flow, the rivers of Europe may be grouped into the following categories.
1.The Loire (1020 Km):
The Loire is the longest river in France. It rises in the “Central Massif” of France, passes through a rift valley, and flows to the northwest before it meets the Bay of Biscay. Orleans and Nantes are important towns on the Loire.
2. The Rhine (1320 Km):
The river Rhine rises in the Swiss Alps and flows through Switzerland, France, Germany, Netherlands, and finally drains into the North Sea at Rotterdam in the Netherlands. As a commercial artery, the Rhine is unrivaled among the rivers of the world. The Neckar, Main, and Moselle are the chief tributaries of the river.
3.The Seine (780 Km):
River Seine rises in the Cote D’or hills located in the northeast of France, flows through Paris Basin, and drained into the English Channel. It is the most important river in France. As the Seine enters Paris, it receives its great tributary, the Marne and after crossing the capital city, it receives the Oise. Le Havre on the estuary is the greatest port in France.
4.The Elbe (1165 Km):
The Elbe is a river in Central Europe. It rises in the Alps of the Czech-Polish border and flows across the Czech Republic and Germany to the North Sea. The river is connected by canals with the Baltic Sea, the Ruhr region, and the Rhine.
5.The Vistula (1047 Km):
The Vistula is the longest river in Poland and it is also the largest of the rivers meeting the Baltic Sea. It rises from the Alps flows eastward and then northward through Poland and empties into the Baltic Sea after forming a delta. Warsaw, the capital of Poland, lies on the Vistula.
6. The Oder (930 Km):
The Oder is a major river in northern Europe. It rises in the Oder mountains of the Czech Republic, flows through Poland and Germany and empties into the Baltic Sea.
7. The Onega (400 Km):
It rises from the Voldai, flows northward and is drained into the North Sea.
8.The Pechora (1940 Km) :
River Pechora rises in the middle of Ural mountain flows northward and drains into the North Sea (Arctic Ocean).
9. The Muse (925 Km):
River Muse originating from Vosges mountain flows through France, Belgium, and Netherlands and is drained into the North Sea.
10. The North Dvina (750 Km):
This Russian river rises in the Voldai; adjacent to the Ural mountain, flows across the Russian Platform and enters into the White Sea.
1.The Volga (3690 Km):
The longest river in Europe is the Volga and it is the main waterway of Western Russia. The river rises in the Voldai hills, northwest of Moscow, and flows south-eastwards, through Russia to empty into the Caspian Sea near Astrakhan. Rivers Oka and Kama are two important tributaries of the river Volga.
2. The Ural (2438 Km):
The third longest river in Europe is the Ural. It rises in the south-eastern Ural mountains. It flows south and then southeast and empties into the Caspian Sea. The river marks the boundary of Europe and Asia, south of the Ural mountains.
It is navigable for 1460 Km but freezes in winter. It is connected with the Volga by a canal.
3.The Rhone (813 Km) :
Emerging from the Rhone glacier in the Swiss Alps, the river flows over Switzerland and France to meet the Mediterranean Sea.
4. The Ebro (800 Km):
The Ebro is the longest river in Spain. It rises in the Cantabrian mountains and empties into the Mediterranean Sea.
5.The Dnieper (2285 Km):
The Dnieper is the fourth largest river in Europe. It rises in the Voldai hills, flows southward through Belarus and Ukraine, and meets the Black Sea. About 1669 Km stretch of the river is navigable for ten months. Important cities on the river include Kyiv and Dniepropetrovsk.
6.The Dniester (1352 Km):
The Dniester is a river of Moldavia and southwestern Ukraine. It rises in the Carpathians and flowing south and east, meets the Black Sea near. Odessa.
7. The Don (1920 Km):
It rises in the Central Russian highlands near Tula. It flows to the south and enters the Sea of Azov. The Donetz is an important right-bank tributary of the river. Rostov is the largest river port on the Don.
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1. The Danube (2857 Km):
The Danube is the second-longest river in Europe. It rises in the Black Forest mountain of Germany and flows through nine countries of south-eastern Europe, such as Germany, Austria, Hungary, Romania, etc. finally it splits into three channels and meets the Black Sea forming a delta.
In the Hungarian Plain, the Danube receives three large tributaries-the Drava, Sava, and Tisza. On its banks lie four capital cities-Viena, Bratislava, Budapest, and Belgrade. There is no river in the world that flows along nine countries, as well as four capitals of them, are situated on the banks of the river.
So, it is called the ‘best international river of the world’ or ‘The most significant international river’.
2. The Po (660 Km) :
The Po is the longest river in Italy. It rises in the Italian Alps and flows eastward to the Adriatic Sea. The fertile Po valley is also known as the ‘Plain of Lombardy’.
3. The Thames:
The Thames is an important river of U. K. It rises in the Cotswold Hills in the west and enters the region through the Goring Gap. The river flows eastward and drains into the Dover Strait.
Lakes of Europe:
Innumerable lakes are found in Europe. They may be grouped as follows.
Lakes in the Plainland:
There are many important and large lakes found in the plain land of Europe. Two large freshwater lakes of Europe Ladoga (18130 sq. km) and Onega (9842 sq. km) are located in the northwest of Russia.
Ladoga is the largest lake in Europe. Other important lakes are Saima in Finland; Vanern or Vener, Vetter or Vattern in Sweden; and Balaton in Hungary.
Lakes in the Mountainland:
There are many picturesque lakes in the Alps region of Switzerland, such as Zurich, Geneva, Lucerne, and Constance. Near the border of Italy are Lugano, Como, Garda, and Maggiore lakes. In England, there is Windermere, Ullswater, and in Scotland is Lomond. All these mountain lakes are very much attractive to tourists.
Finland in Europe is known as the ‘Country of Lakes’ as there are about forty thousand lakes here.
The climate of Europe is generally temperate in nature. But there are great variations from one region to another. The important characteristics of the climate of Europe are as follows:
Although the continent of Europe is small in size and lies in the temperate zone, its climate varies from one region to another because of the following factors:
1. Latitudinal Extent:
Europe extends from 35°N to 71°N latitude and thus, nearly the whole continent lies within the temperate zone. As the midday sun is never overhead beyond the tropical region, temperatures are never very high and decrease towards the poles.
So, the Mediterranean region of southern Europe is sunnier and warmer than the Tundra region of the extreme north.
2. Influence of the Sea:
Western and southern Europe lie beside the Atlantic Ocean and the Mediterranean Sea respectively. So, they have an equable climate with mild winters and warm summers. The severity of the climate increases eastwards due to greater distance from the sea. Thus, eastern Europe has hot summers and very cold winters.
3. Altitudinal factor:
Location of Highlands-The effectiveness of any wind depends largely on the layout of the highlands. Higher Alpine mountains and the highlands of Scotland and Scandinavia influence the climate by obstructing the air masses.
The altitude of the Alps mountains and the plateaus influence temperature conditions also.
4. Influence of Winds :
Nearly the whole of Western Europe is under the influence of the. south-west westerlies which blow all through the year. These winds cause rainfall throughout the year with a winter maximum, except in the south where trade wind blows in summer.
5. Influence of Ocean Currents :
Western Europe is comparatively warmer than the eastern coast of any continent in the same latitude. This is because the warming influence of the warm North Atlantic Drift is carried to the shores of Europe by the south-westerly winds.
The same warm current keeps the ports of Norway in north-western Europe ice-free even in winter. On the other hand, in the Gulf of Bothnia which lies away from the influence of the North Atlantic Drift, ports remain ice-bound in winter.
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Temperature :
In general, temperature decreases from the south to the north. In summer when the sun is overhead in the Northern hemisphere, the sun’s rays are more direct in Southern Europe than in the north.
Thus Southern Europe becomes warmer than Northern Europe. Temperature decreases from 27°C in the south to below 15°C in the north.
In winter, due to the influence.. of the ocean current temperature remains around 10°C in the west. But in the north-east temperature drops too. -12°C.
As the world pressure belts swing to the north in summer in the northern hemisphere, the southern hemisphere part of Europe comes under dry north-east Trade wind.
But moist south-westerly winds blow over the rest of the continent. In winter, world pressure belts shift to the south and the westerly replaces the Trade wind in the Europe.
Moistsouth-westerly wind gives rain all over the continent, but the amount decreases from west to east. In summer, the westerlies after causing rainfall (50- 100 cm) in north-western enter further inland where low pressure prevails due to higher 15°Ctemperatures.
Thus most of the rain (25 cm to 50 cm) in central and eastern Europe, comes in summer where rainy periods alternate with dry hot spells. Along the Norway coast, rainfall is 200 cm. In the Philly region, it is 100cm – 200cm.
The continent of Europe can be divided into the following climatic regions on the basis of variations in temperature and rainfall.
The characteristics of natural vegetation depend on climate. Natural vegetation in Europe has been greatly influenced by climate. The variety in climate has resulted in the variety of natural vegetation. Europe has five major natural vegetation belts, which are as follows:
In extreme northern parts of Europe in Norway, Sweden, Finland, and Russia due to long winters (9/10 months), the ground remains frozen. So, only in short summer (2/3 months) when the surface thaws, Grass Tundra like mosses, lichens, and colorful flowers grow.
Bush Tundra namely birch, willow, alder, and juniper, grow in the south where the temperature is a little more. The region is named after the vegetation ‘Tundra’ means moss/ algae.
To the south of the Tundra lies the Taiga Region in Norway, Sweden, and Russia there is an extensive forest of softwood coniferous trees. Tall and straight trees like pine, fir, spruce, larch, etc. Due to severe Snowfall trees are conical with small needle-shaped leaves.
These trees yield valuable softwood for making wood pulp and for use as timber. Fruit-bearing trees are rarely found in this belt. This forest in Asia is called ‘Taiga’ which is the largest forest in the world.
South of the coniferous belt in Central and Western. Europe there lies this belt extending from the British Islands to the central parts of Russia. This is a region of mixed forests.
Both coniferous trees and mostly deciduous trees which shed their leaves in Autumn or winter flourish. So, Autumn is referred to here as “Fall”.
The forest is also known as ‘Temperate Hardwood Forest’. Trees like oaks, ash, beeches, maples, chestnut, birch, and poplar are common and are mixed with pines.
Forests are found because rainfall is enough and the dry season is not long. These trees are not tall and there are a number of meadows or open ground amidst them.
This belt is confined to Southern Europe along the Mediterranean Sea coast. It includes countries such as Southern France, Italy, Greece, etc. This belt has sunny warm (24°C) and dry summers and mild (80°C) and wet (75 cm) winters.
This type of climate supports evergreen trees and scrub which have special devices to combat long periods of drought and summer. heat. The trees grown here have long roots and thick bark to resist drought. They have broad, thick, and waxy or oily leaves. They are not tall and straight like the trees of the Taiga region.
The common trees are olive, cork-oak, cedar, laurel, chestnut, stone-pine, walnut, fig, citrus trees, and vine.
The word ‘Steppe’ comes from the Russian word “Step” meaning “a vast treeless plain”. In the south-eastern and central part of Europe where rainfall is very low, there is an extensive temperate grassland known as the “Steppe grasslands”.
This region extends over the area of Southern Russia and the plains of the Danube in Romania and Hungary. The natural vegetation of this region consists of grasses and herbs.
However, along the banks of the rivers, where sufficient water is available, willow, elm, maple etc. are found. The short but soft, juicy grasses of the Steppes offer an ideal grazing ground.
Introduction:
The Ruhr industrial region of Westphalia in Germany is named after the Ruhr, a tiny tributary of the Rhine. It is one of the best industrial regions in Europe as well as the world.
The present Ruhr industrial region has more than 30 to 35 large cities which have merged to form the world’s largest ‘Industrial Conurbation’. (‘conurbation’ is a term meaning a continuous industrial area formed by the merger of many industrial cities and towns).
Location:
Ruhr industrial. the region is located at the confluence of the river Rhine and its tributary the Ruhr. The region once occupied the area between the Lippe and Ruhr rivers. At present, it extends up to the Wupper valley in the south and Munchen Gladbach in the southwest.
Boundary:
This region is bounded to the north by the river. Lippe; on the west by the Vosges and Rhine river; on the south and east by the Sayarland highlands.
Area and Extension:
The present Ruhr industrial region covers about 4600 sq. km area and stretches for 130 km in the east-west extension and 65 km in the north-south extension.
Physiographic characteristics:
The region is almost flat with an average elevation of around 250 meters above sea level and slopes gently from east to west. In some places are found small hills made of sands, stones, and pebbles deposited by glaciers in the ice age.
Rivers:
The Rhine is the principal river of the Ruhr industrial region. The Rhine is joined by its four tributaries (Ruhr, Lippe, Elms, and Wupper) flowing through this region. All of them are interlinked by canals and provide a good navigation system.
Climate:
The climate of this region is cool and temperate in nature. Well-distributed rainfall (Average annual rainfall is about 50 cm to 70 cm) and favorable temperature (Summer 15°C and winter around 0° -2°C) assist both agriculture and industry in the Ruhr region.
Soil:
Fertile alluvial soil along the riverbanks, podzol soil in the north, and chernozem soil in the south are found here which are good for agriculture.
Natural Vegetation:
Forests in this region have been filled and cleared to a considerable extent as agriculture, industry, and settlements have grown.
Planned afforestation has been done to control the pollution caused by the industrial region. Trees like oak, birch, elm, pine, fir, etc. are commonly found in the reserve forests of this region.
Agriculture:
This region is dominated as an industrial region and is not very much developed in agriculture. However, mixed farming is practiced to satisfy the demand of urban people. Crops such as wheat, barley, potatoes, sugarbeet, and a variety of vegetables, fruits, and flowers are grown in this fertile plain.
They supply most of the agricultural needs of the industrial towns. Cattle and sheep are also reared to produce milk, meat, wool, etc.
Minerals:
The greatest asset of the Ruhr region is the presence of 130 thick seams of excellent cooking coal and best quality anthracite and bituminous coal. It accounts for 80% of the total coal production of Germany. This plays an important role in the development of industries here.
So, coal is the lifeline of this region. Other important minerals of this region are lead, zinc limestone, and low-grade iron ore. Petroleum is also mined in some areas.
Transportation system:
Ruhr industrial region is well developed in different modes of transportation such as roadways, railways, and waterways. The Rhine is the busiest and most navigable waterway in Europe.
This river along with its tributaries, namely the Ruhr, the Lippe, and the Dortmund-Ems and Lippe canals provide cheap access to the North Sea. There is also a dense network of rail and roads in the region.
Industries:
This is the most important industrial region of the world. The region accounts for more than 80% of the steel output of Germany. It is also the leading manufacturing district for coal by-products, metal products, machinery, textiles, and chemicals.
Factors favoring the growth of industries in the Ruhr region are as follows:
Queen of the Ruhr:
The most important steel works, for this reason, are at Essen which is located in the Ruhr heartland. The city known as the ‘Queen of the Ruhr’, boasts of the iron and steel industry run by the famous company ‘Krupps and Demag’.
Manchester of Germany:
Gladbach is the most important textile center of the region and is famous as the ‘Manchester of Germany’.
Ruhrgrebeit:
The heart of the Ruhr industrial region called the ‘Ruhrgrebeit’ extends from Dortmund to Duisberg and accounts for the production of 80% of the country’s steel.
Population and Settlement:
Due to the development of transportation and industries, this region is densely populated. Settlements are found to be uniformly thick right through the region from south to north.
Important cities:
Important towns and cities of the Ruhr industrial region are-
Introduction:
The lower Thames Basin lies in the south-eastern corner of the United Kingdom, and is called the ‘London Basin’. The word ‘Basin’ means ‘lowland formed by a river’.
London, the capital of England as well as the United Kingdom is located in a saucer-shaped lowland surrounded by highlands, except for a small portion in the east.
This region of lowland is formed by the Thames river as such the basin named the capital city of London is called London Basin’.
Location :
London Basin is located in the southeastern part of Great Britain in the lower Thames river basin. The river Thames flows through nearly the centre of the region from the west to the east.
Boundary:
Except in the east, the London Basin is surrounded by highlands. It is bordered on the north by Chiltern Hills and the south by North Downs and Hampshire Downs.
The western boundary of the basin is the Berkshire Downs and White Horse Hills. At the eastern boundary where the land is flat, the Thames river flows over it to the Dover Strait.
Area and Extension:
London Basin comprises about 7750 sq. km. The core of the London Basin is represented by the Greater London area, stretching from Enfield to Epsom and from Oxbridge to Upminister, surrounded by the chalk dip slopes.
Population:
The population of the London Basin is about 12.5 million.
Physiographic Characteristics:
The London Basin is a triangular shallow depression or trough formed by a downfold in the chalk upon which has been deposited sands, gravels, and clays. The basin is not evenly flat Glacier-borne stones, and pebbles have accumulated in places to form an undulating surface.
The bordering hills have steep slopes and are made of chalk and limestone. The height of the North Downs varies between 270 to 320 meters while that of Chiltern Hills in the north varies between 235-250 meters.
London Basin may be sub-divided as follows :
Rivers:
The principal river of the London Basin is the Thames. It rises in the Cotswold Hills lying in the west and enters the region through the Goring Gap, between White Horse and Chiltern Mountains.
Then the river flows eastward and drains into the Dover strait. Many hill torrents have joined the Thames river, such as Lea and Roding from the north; Wey and Moly from the south.
Climate:
The climatic type of London Basin is popularly known as the ‘West coast maritime climate’ or ‘British type of climate’. In general, it has warm summers (17°C) and cold winters (4°C). Moist and cool climate prevails in this region throughout the year.
Rainfall is basically cyclonic with a winter maximum. It ranges from 75 cm on the crest of the North Downs to 60 cm on the Thames side. Snowfall occurs in winter.
Soils:
Once the London Basin was covered by a shallow sea where sediments like the ‘London clay’ were deposited about 70 million years ago.
Later when the basin was raised above the sea, patches of sand called ‘Bagshot Sand’ covered this clay in some places. At the margins of Chalk hills was deposited a pebbly and sandy soil called ‘Woolwich Sand’.
Natural Vegetation:
Owing to dense settlement, the growth of industries, and urban centers the original natural forests have been destroyed. Only on the highlands, do coniferous trees like oak, pine, and beech grow. Due to little rainfall, there are some grasslands in these basins.
Agriculture:
As the London Basin is very densely populated and highly industrialized, agriculture is restricted only to a small extent. To fulfill the local demand, advanced, mechanized mixed farming is practiced in some parts of this region. Varied crops are cultivated on small farms.
Vegetables i.e. potatoes, turnips, carrots, cauliflowers, cabbages, tomatoes, fruits, and flowers are produced and which are sent by trucks to the cities.
So this type of farming is also called ‘Truck farming’. Some cereals like wheat, barley oats, etc. are also produced in the north and west of the London Basin.
Animal Husbandry and Poultry Farming:
On the pastures found in the Chiltern and Downs Highlands and slopes of the mountains cattle and sheep are easily reared. Chicken, turkey, etc. are supplied from poultry farms.
Thus sufficient milk and milk products (butter, cheese, etc.), meat, and wool are also produced here. In the dairy industry, the region is quite developed.
Fishing:
Fishing is also practiced in this region.
Transportation System:
There is a good network of modern roadways, railways, and waterways. London basin is an important center of International air routes. There are five airports, such as Heathrow, Foulnes, Stansted, Black bush, and Croydon.
Heathrow is one of the busiest airports in the world. The underground and overground railway is very developed in London. London is an important river port also.
Minerals:
Other than some limestone and sand, there is no other mineral in this region.
Industries:
The London Basin is one of the most industrialized regions of the world. It is the principal industrial and trading center of the United Kingdom.
After the ‘Industrial Revolution’, rapid industrialization has taken place here. The following factors are responsible for such tremendous development in industry and trade in London Basin.
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Population and Settlement:
Due to its economic prosperity, London Basin has become a densely populated area. It is the most densely populated region of the U.K. with more than 1.25 crore people.
Numerous people live here because of developed communication, growth of agriculture and industry, and attraction of the capital.
1. London:
London is the capital of England, as well as the United Kingdom, and the leading city of the British Commonwealth and Empire. London is not only the largest city in this region but also the main city and port of the whole of U. K.
It is the third largest city in Europe after Paris and Moscow. It is an industrial and trade center. It is an important international airport center also.
Though London is a river port yet it is famous as an Entreport, as it imports materials which it again exports. For example, After importing tea, coffee, spices, etc: from various countries, it processes them and then exports them to different countries in Europe and other continents.
Many tourist places lie in London. Near London lies the famous Greenwich Observatory in the suburbs of Greenwich, over which extends the meridian of 0° longitude or the Prime Meridian. London is the most cosmopolitan city in the world.
2. Reading :
Reading is located at the confluence of the Thames and the Kennet is an industrial town. Engineering, biscuit, textile, etc. factories are located here.
3. New Bury:
It is located on the banks of the Kennet river. It is a busy market center. It is also famous for engineering, flour milling, and cotton textile factory.
4. Others:
Other important towns include Croydon, Chelmsford, Chatham, Slough, St. Alban, and Rochester.
Introduction:
The term ‘Polder land’ is derived from the word ‘Polder’ which means reclaimed from under the sea’. So Polder land is actually low land that has been reclaimed from the shallow submerged lands of river marshes or the sea and is surrounded by dykes.
Polder land:
In the Netherlands, an area that has been reclaimed from the Zuider Zee (formerly, a landlocked inlet of the North Sea) and has been surrounded by the dykes to protect it from the seawater is called ‘Polder land’.
It is drained by pumping the water into canals and has made gradually very much fertile for agriculture.
Location of Polder Land:
The Polderlands latitudinally extend roughly between 51° N latitudes in the south and 54°N latitudes in the north and longitudinally between 3°E longitude in the west and 7°E longitude in the east.
The boundary of Polder land:
The Polder lands are bordered on the north and west by the North Sea, on the south and southwest by Belgium, and on the east and southeast by the remaining parts of the Netherlands.
Area and Extension:
The Polder lands cover about 16,700 sq. km and made up around 30% of Holland (meaning ‘the lowlands’) or the Netherlands. Nearly 70% of the Polder lands lie below sea level.
How a Polder land comes into being?
The reclamation of Polder lands started in the Netherlands, in ‘the eleventh century. Then the reclaiming process of Polder land was primitive. It has been modernized with the advancement of technology.
There are more than three thousand Polders in the Netherlands. Among these, Zuider Zee is the largest. Most modern and important projects on reclaiming polders are-
1.Zuider Zee Project was started in 1918. A dyke has been made to form a lake called Ijsselmeer from which lands have been reclaimed at different stages such as-
2. Zeeland Project is located in the southern part of the Netherlands.
The main stage of reclamation of marshy land or parts of shallow seas is to seal the area with concrete dykes on all sides. Inside the circular dykes, there are rings of canals to drain the water.
After that musky water is pumped into the enclosure. As the sediment settled down, the water is pumped out by windmills (now mainly electricity operated).
Thereafter, the alluvium dries up and then the land is left to become out salt-free for a few days. After that, the land is used to cultivate different grasses such as hey, clover, alfalfa, etc. for fodder.
When the land becomes salt-free and favorable for cultivation different crops and flowers are cultivated.
Physiographic Characteristics:
The entire region is not only flat but also very low and mostly lies below sea level. Some parts of this region are located about 7 to 10 feet below sea level. If stagnation of rainwater occurs, it is pumped out to the draining canals. Most of the areas of this region are covered with marine clays.
Rivers of Polder land:
The Rhine (Principal river) and its distributaries such as the Waal (Val), Lek, Maas, and the East and West Schelde are the main rivers of Polder lands. All these rivers form deltas as they enter the North Sea. The Ijssel, another distributary flows into the Ijsselmeer.
The climate of Polder land:
Polder land is located in the cool temperate climatic region, but the climate is moderate because of the warm North Atlantic Drift. The average winter temperature is 3°C and the average summer temperature is 16°C. In the interior, summers are slightly warmer and winters are slightly colder.
Here the south-westerlies bring rainfall throughout the year. The average annual rainfall is around 75 cm with a winter maximum.
Soils of Polder land:
Alluvial soils are found along the banks of rivers. Most of the soils of Polder lands are saline clay.
Natural Vegetation of Polder land:
In this man-made land, there is simply no natural vegetation. The coastal dunes are planted with sand-binding grasses, reeds, and pines. Here trees like oak, birch, and grasslands are very common.
Agriculture:
The Polder lands are the richest agricultural regions of the Netherlands. With a view to decreasing the salinity of soil in the new polders, grasses like hay, clover, alfalfa, etc. are cultivated. These nutritious grasses are used as fodder.
In the old salt-free Polder lands different crops such as wheat, barley, eat, potato, mustard, and flax as well as strawberries and other fruits are cultivated. Farmers mainly practice ‘mixed farming’, where crop cultivation and cattle rearing are practiced under the same farm.
Here in the vast rolling tracts, different colorful flowers such as Tulips, Cosmos, Gladiuli, etc. are grown. Moreover, in the cold regions with less sunshine, vegetables and also flowers are grown, in ‘Green Houses’.
Livestock Raising:
Moderate temperature, year-round rainfall, and clayey soil are more suitable for grass than to crop farming. So, pasture dominates. Cattle are reared on rich pastures where hay, clover, and alfalfa grew abundantly.
Thus dairy farming is the keystone of Dutch activities and it provides butter and cheese for which the Netherlands is internationally famous.
Fishing:
Fishing is also important in the new Polder lands. Ijsselmeer (A lake, North section of former Zuider Zee which receives river vessels) has freshwater fisheries while shrimp fishing and cultivation of oysters and mussels are important in the Zeeland.
Mineral Resource:
The region is not so rich in mineral resources. The principal mineral of Polder land is natural gas. At Groningen, there is a large reserve of natural gas. It is one of the largest gas fields in the world. Some mineral oil is available at the Hague.
Industries:
Polder land is famous for its industries-Iron and steel, Petro-chemical, electronic and electrical goods (Phillips Company), ship-building, dairy, food-processing, cotton-textile, paper, leather, and perfumery or cosmetics industries have developed here.
Important industrial centres are Amsterdam, Rotterdam, Groningen, The Hague, Harlem, Leven, Ijmuiden, Leiden, Flashing etc.. Amsterdam is world-famous for its diamond cutting and polishing.
Transportation Sysem:
The transportation system in Polder land is well-developed. It has an excellent network of modern roadways and railways. Rivers and canals provide easy means .of communication.
The circular dykes are also used for transporting the estuary of river Lek, the largest port of the region, and Amsterdam transportation. Rotterdam, located at the est port of the region, Amsterdam is also famous as a port.
Population:
Polder land is densely populated because of its developed transportation system, advanced agricultural and industrial economy, and most modern way of livelihood.
class 7 geography book west bengal board
Amsterdam:
Amsterdam is the principal and capital city of the Netherlands. It is also an important port and industrial center. It is famous for electronic goods, shipbuilding, cigarette and cigar making, and diamond cutting.
It is popularly known as ‘Venice of the North’ because of its navigation and scenic beauty.
Rotterdam:
This is the busiest port in the world and an important town in the Netherlands. It is also known as ‘Europort’ as most of the European trade is carried through this port.
The Hague:
The Hague is the seat of the Parliament and of the ‘International Court of Justice’.
Others:
Other important cities are Eindhoven, Groningen, and Leiden.
Introduction:
The continent of Africa is the second largest continent in the world (coming next to Asia). Africa is a huge continent of infinite variety. It is called an ideal continent.
Man is believed to have appeared first on the face of the earth in East Africa but till the end of the 19th century, Africa was known as the ‘Dark Continent’ as most of the continent was a mystery to the rest of the world.
The vast Sahara desert, dense unhealthy forests, and rugged topography prevented travelers from venturing into the continent.
Problems of accessibility, uncomfortably hot and humid climate, presence of beasts of prey, etc. the light of modern civilization could not reach this continent till recent times.
Read and Learn More WBBSE Notes for Class 7 Middle Class Geography
So, this continent was commonly known as the ‘Dark Continent’. It is interesting that the ancient civilization of Egypt also took place in the northeastern part of the continent of Africa.
Location:
The continent of Africa is located to the south of Europe and to the southwest of Asia. From north to south Africa extends from 37° (37° 14′) north Parallel of latitudes to 35° (34° 50′) south parallel of latitudes.
Longitudinally Africa extends from 18° (17° 33′) west meridian in the west to 52° (51° 24′) east meridian in the east.
Therefore, three important parallels of latitudes, the Equator (0°), Tropic of Cancer (232°N), and Tropic of Capricorn (232°S) are extended through this continent.
The Equator, passing through the middle of Africa has divided the continent into the western part of north Africa. The Prime Meridian has divided the continent into two parts-eastern and western hemispheres.
Thus, Africa is the only continent that is crossed by the Equator, both the Tropics, as well as the Prime Meridian, and so, covers parts of each hemisphere-eastern, western, northern, and southern.
Boundary:
Africa is bounded on the north by the Mediterranean Sea and the Strait of Gibraltar, across which lies the continent of Europe. In the south are located parts of the Indian Ocean and the Atlantic Ocean.
The continent is bounded on the east by the Indian Ocean and on the northeast by the Gulf of Aden, the Red Sea, and the Suez canal.
The Gulf of Guinea and the Atlantic Ocean are located on the western boundary of Africa. The narrow Red Sea separates Africa from Asia while the Isthmus of Suez used to join these two continents before the Suez canal was dug across it in 1869.
In the northwest, the narrow strait’ of Gibraltar separates Africa from Europe. Africa may be called a ‘Continent of four seas’, because, the Mediterranean sea, Red sea, Indian Ocean, and Atlantic Ocean have surrounded this continent.
Area:
The continent of Africa accounts for a fifth of the world’s land surface. It covers an area of 3,02,21532 sq. km which is nine times the -size of India. It is the second-largest continent in the world according to its size and population.
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Extension:
Africa stretches for a distance of about 8000 km (5000 miles) from north to south and about 7400 km (4600 miles) from west to east. The northern part of the continent from east to west is a wider part and gradually tapers to a point in the South.
The tips of the continent are in the east of Africa is the Cape Guardafui, in the west is Cape Verde, in the north is the Cape Bon, and in the south is the Cape Agulhas. The famous ‘Cape of Good Hope lies in the south of Africa.
Population:
There are nearly 1-2 million people in Africa(2016).
Relief/ Physiography Of Africa :
Africa is a continent of plateaus. This vast plateau is called the ‘Continental plateau’. The African plateau is very much diversified in its topography. The plateau varies in elevation between 305 m and 2440 m. But it is not generally mountains.
There are four physiographic divisions in Africa. These are as follows:
Atlas Mountain which stretches over 2250 km across North-west Africa in a series of ranges through Morocco, Algeria, and Tunisia, belongs to the fold mountain system.
The ranges are actually a continuation of the Alps of Europe and were formed when the Himalayas originated.
It is named after Atlas, the ancient Roman God of this region by the Greek people who live on the other side of the Mediterranean Sea. From north to south, the ranges are-
This is an extensive plateau that extends from the Atlantic coast in the west to the Nile river in the east. It is not so high. Average height ranges between 300 m and 600 m. It slopes towards the north and west.
The plateau is relatively higher in its central part, called the Tibesti, wherein lie many peaks, such as Emi Koussi (3415 m). The most significant part of this plateau is ‘The Sahara’, the largest hot desert in the world.
Other important deserts are the Libyan and Nubian deserts. The plateau of Ahaggar lies in the middle of the Sahara. Ahaggar or Hoggar (2918 m) is the highest point of the residual uplands of Ahaggar.
Lake Chad lies in the south of the Sahara Desert. There are hundreds of oases scattered throughout the Sahara. Fouta Djallon, Kong, and Cameroun Mountains are situated to the north of the Guinea coast.
This is the highest part of Africa. Highlands stand in the eastern and southern parts of Africa. The low plateaus of Central Africa have gradually increased in height and have merged into the highlands of Abyssinia or Ethiopia. The average height is about 2000 meters.
The Eastern Highland is characterized by its spectacular feature, the ‘Great Rift Valley which is the longest, about 6400 km. of the world. The largest rift valley extends from the Red Sea coast in the north up to Mozambique in the south.
The ‘Great Rift Valley’ has two arms- western and eastern-joined together. The western arm extends to the north from lake Malawi through lake Tanganyika-one of the world’s deepest lakes, lake Kivu, Edward, and finally up to lake Albert.
The eastern arm extends from Malawi through lake Turkana (Rudolf) to the Red Sea and then through the Gulf of Aqaba to the Dead Sea in Jordon. Lake Victoria, Africa’s largest and the world’s third-largest lake, lies between the two arms of the rift valley on the surface of a plateau.
Several mountain chains radiate from the Ethiopia mountains in the north-south direction. The northern range stretches northward along the Red Sea coast. The southern range runs parallel to the east coast.
The southern range has formed a few peaks of considerable altitude. Mount Kilimanjaro (5895 m) Africa’s highest mountain peak lies here. Mt. Kenya (5194 m), Mt. Kilimanjaro, and Mt. Kenya are of the Block mountain group. Mt. Ruwenjori, Mt. Elgon, etc. are also important. These are extinct volcanoes.
Southern Highland is very high and has formed a great mountain wall by the Drakensberg or “Dragon’s mountain”. New Veld mountains are situated at the southern edge of the south African plateau.
They are the old fold mountains. The southern mountain plateau descends the sea by a series of steps of considerable width. These steps are called Karoos. They are noted as ‘Great Karoo’ and ‘Little Karoo’.
Bigger steps are called ‘Great Karoos’ while the smaller ones as ‘Little Karoos’ in the Cape Province of South Africa. To the west of this plateau, there are two hot deserts-the Kalahari and the Namib.
All around the continent, the narrow coastal plains form the major lowlands of Africa. The coastal lands of Africa are low. They are below 200 meters in height. The Coastal plains of the Mediterranean Sea in the north and the Atlantic Ocean in the west are a little wider.
Africa lacks low plain lands except for narrow basins of the Zaire river, the Zambezi river, the Orange river, the Niger river, the Nile river, etc. The Volta river basin and the riverine e plain of Gambia are also important. The coastline of Africa is not broken but is very long.
In Africa, there are a few islands, such as Madagascar (the largest island of Africa) and Zanzibar in the east, Canary and Madeira in the northwest, and St. Helena in the west.
Many rivers are found in the continent of Africa. The characteristic features of the rivers or drainage system of Africa are as follows:
According to their direction of flow rivers of Africa may be grouped into the following categories:
Important Rivers Of Africa
| Types of Rivers | Name of the Rivers |
| 1. North-flowing Rivers | The Nile |
| 2. West-flowing Rivers | 1. Congo or Zaire, 2. Niger, 3. Senegal, 4. Gambia, 5.Orange etc. |
| 3. East-flowing Rivers | 1. Zambezi, 2. Limpopo. |
| 4. Inland Rivers | 1. The Chari, 2.Lo, etc. |
The Nile (6690 km):
This is the longest river in Africa as well as in the whole world. ‘Nile’ is a word derived from the Latin word ‘Nilus’ means ‘which source is unknown’.
The The’Kagera’ river originating in the highlands of Rwanda-Burundi and falling into Lake Victoria is believed to be the source of the Nile river.
The river flows Straight to the north up to the tenth parallel in Sudan. Here the river is known as the Bahr-El-Jebel. From the west comes the river Bahr-El-Ghazal and the Sobat from the east.
The combined course of these rivers flows by the name White Nile which is the main stream of the Nile. The longest tributary of the Nile, the Blue Nile joins the White Nile to form the Nile at Omdurman and Khartoum on the left and right banks respectively.
Between Khartoum and Aswan the Nile passes through six cataracts and receives another tributary, the Atbara coming from the north of the Ethiopian Highlands.
From Aswan to Cairo is the lower course of the Nile and the delta course from Cairo to its mouth. The river Nile formed a large delta as it meets the Mediterranean Sea.
The Congo or Zaire (4700 km):
The Congo renamed Zaire (from ‘Zari’ means ‘huge mass of water’ is the second largest river in Africa and has the world’s second-largest river basin after that of the Amazon. The river originated in the plateau of Katanga, southwest of lake Tanganyika along the Zambia-Zaire border.
In the source region, the river is known as Lualaba. The river flows as Zaire after crossing the Equator. This river has crossed the Equator twice, and therefore, receives much volume of water through its different tributaries.
The mighty river cuts through the heart of the dense equatorial forest of Africa in a long twisting course until it reaches the waters of the Atlantic.
The Ubangi (1400 km) and Kasai (2153 km) are important tributaries, and along with the main river, serve as important waterways. The river has formed two well-known waterfalls, such as Stanley and Livingstone.
The Niger (4180 Km):
This is the third longest river in Africa and the principal river of west Africa. It rises as the ‘Tembi’ in the highland of Fouta Djallon along the Guinea Sierra-Leone border.
Then it flows northward and finally turns southward to drain into the Gulf of Guinea in the Atlantic Ocean. The river drains of an area of 1.5 million sq. km affect the lives of millions and are rightly called the ‘life giver of Mali and Niger’.
In the lower reaches, the river is joined by its most important tributaries the Benue – the largest tributary and the Kaduna. Below the confluence of the Benue the river delta begins.
Senegal (1641 Km):
Senegal is an important river in west Africa. It rises in the Fouta-Djallon highlands and meets the Atlantic Ocean. Senegal is a navigable river that flows along the northern border of the ‘Republic of Senegal’. The Senegal river is the longest river in the Republic of Senegal.
The Gambia (1120 Km):
The Gambia is also an important river in West Africa. It rises in the Fouta-Djallon highlands flows through the heart of the Republic of Gambia and meets the Atlantic Ocean.
The Volta (1600 Km):
The Volta is the most important river of Ghana, which has two main branches-the White Volta and the Black Volta. Rising in the Guinea highlands, the river empties into the Atlantic Ocean.
The Orange (2140 Km):
The Orange is the longest river in the Republic of South Africa as well as the fifth longest river in Africa. It originates in the Drakensberg Mountains of South West Africa and flows westward through semi-desert and desert areas.
Then it flows through the grassland of Veld towards the west to drain into the Atlantic Ocean. The river Vaal is an important tributary of the Orange River.
Twenty-nine reservoirs have been constructed on this river for irrigation and a number of hydel power stations are developed on this river.
The Zambezi (3540 Km):
This is an important river in South Africa and it is the fourth largest river in Africa. The river originating in the western part of the southern highland flows southward and then curves eastward to meet the Indian Ocean (Mozambique Strait).
The magnificent and world-famous Victoria Falls lies on this river. With a height of 108 meters (more than twice as high as the Niagara Falls of North America), the falls stretch for more than 16 km across Zambia from Zimbabwe.
The Kariba dam on the Zambezi in Zambia is 128 meters high and its reservoir is among the largest (5180 sq. km) of all man-made lakes. The Cubango is an important tributary of the Zambezi.
The Limpopo (1900 Km):
This is another important river in South Africa. It originated in the western part of Transvaal and flows eastward to drain into the Indian Ocean through Mozambique. The river is infested with crocodiles. Hence the Limpopo river is also known as ‘The Crocodile river’.
There are some inland rivers in Africa. An inland river does not have any outlet to the sea. So an area of inland drainage is an area where all the rivers drain into an inland lake.
An important area of inland drainage in Africa is the Chad Basin that lies to the south-east of the Sahara. The Chari, an intermittent river and ‘Lo’; one flows into Lake Chad that occupies the central part of this basin.
Another area of inland drainage is the ‘Okavango (Cubango) basin of Botswana in southwest Africa.
There are a few big lakes in Africa. These lakes are of two types, i.e.
1. Freshwater Lake:
‘The great Rifl valley’ in East Africa consists of a number of lakes, such as Tanganyika, Rudolf, Malawi, Albert, Edward, etc. Tanganyika (672 km) is the longest as well as the second deepest (1436 m) freshwater lake in the world.
Near the Equator, there is lake Victoria which is the largest lake in Africa and the second-largest freshwater lake in the world. Other important freshwater lakes are Tana and Abaya located in the Ethiopian highland and Benguela lake located in the mountains region of Zambezi.
2. Saline water Lake:
In the southern part of the Sahara desert lies Lake Chad, which is a saline water lake. In northwest Africa, there are a few small saline water lakes in between the Atlas mountain and the Sahara desert.
These small saline water lakes are known as ‘Shotts’. (Arabic word ‘Shott’ means ‘Saline water’).
There is a great variation in the climate of Africa. The general characteristic features of the climate of Africa are as follows:
There are great contrasts in the climate of Africa and these are controlled by the following factors:
Africa extends from 37′ 14′ north to 34° 50′ south latitude. So Africa is the only continent in the world that extends equally into the northern and southern hemispheres.
The Equator (0°) the tropic of Cancer (23%1⁄2°N) and the Tropic of Capricorn passes through this continent. So, it is mostly located in the Tropical, sub-tropical, and Equatorial climatic regions.
About 75% of Africa lies within the Tropical zone. So, most of the continent is hot throughout the year.
Temperature decreases at the rate of 6.4°C for 1000 meter (1 km) increase in altitude. Eastern Highland of Africa, though located in the torrid zone, enjoys a cool climate because of its high altitude.
Mount Kilimanjaro, though located in the Equatorial region remains snow-capped throughout the year. For the same reason, the higher southern Plateau also remains cool.
Extremities of temperature increase with the distance from the sea/ocean. Because of its shape, the northern part of Africa has extremes of temperature. Places in the heart of north Africa are far away from the moderating influence of the oceans.
So, they are very hot in summer and very cold in winter. On the other hand, temperatures in the narrower southern part of Africa are more uniform.
Warm and cold ocean currents move along different parts of the African coast. The cold scenery and Benguela currents keep temperatures down in the northwestern and extreme southwestern coasts, respectively. On the other hand, the warm Mozambique and Guinea currents have a warming influence on the south-eastern and western coasts respectively.
Trade winds blow from the sub-tropical high-pressure belt to the Equatorial low-Pressure Belt. They do not give any rain to the western part of the continent and are also responsible for the formation of the Kalahari and the Namib desert.
Temperature:
Summer occurs in North Africa in the month of June-July and the highest temperature of 52°C prevails over the Sahara Desert. In South Africa where it is winter, the temperature of the Drakensberg mountain in south-east Africa is only 4°C.
From December-January it is winter in North Africa and summer in South Africa. So the temperature of the Sahara Desert drops to 4°C, while it remains high at 21°C in the southern parts of Africa.
In the equatorial region, however, the average temperature throughout the year remains around 27°C, it has year-round summer.
As the Equator, passes through the middle of Africa, Central Africa is under the Low-Pressure Belt and the northern and Southern parts of Africa are under the sub-Tropical High-Pressure Belts.
So, the North-East Trade wind blows over North America. But with the movement of the sub-solar point, Pressure, and Wind Belts also shift. So, in Winter, ‘Westerlies blow over the extreme southern and northern parts of Africa.
In general, rainfall decreases as one goes north or south of the equatorial region, and most of Africa has less than 50 cm of rainfall. Central 1600 Africa as located in the equatorial region receives heavy convectional rainfall throughout the year with an annual average of 150 cm.
Rainfall is less than 15 cm annually in the Sahara Desert. Monsoon wind coming from the Indian Ocean gives rain to the east coast of Africa.
The Sahara, Namib, and the western margins of the Kalahari desert have less than 25 cm of rainfall annually and are truly arid in character.
Based on variations in temperature, air pressure wind, and rainfall, the continent of Africa may be divided into the following seven climatic regions.
As in other parts of the world, climate especially rainfall influences the natural vegetation of Africa to a great extent. According to the variation in climate (mainly temperature and rainfall), altitude, soil, and geographical location, the natural vegetation of Africa may be broadly divided into Seven Natural Vegetation Belts.
Let us now discuss the different types of natural vegetation growing in different regions of Africa.
These forests are found mainly in the Congo or Zaire Basin and the Guinea coast of Africa. These forests are also known as equatorial rainforests. The hot and humid climate favors the growth of dense forests. So, the trees are very huge and tall.
As there is heavy rainfall throughout the year, the trees are evergreen and have broad leaves. Entering or traveling through these forests is virtually impossible because of the dense undergrowth of shrubs and creepers.
Numerous tall hardwood trees like ebony, mahogany, rosewood, and ironwood and giant woody creepers called lianas grow here profusely and form a thick canopy through which no light can penetrate. So, this forest is called the ‘land of eternal twilight’.
The equatorial forests of the Zaire basin are the second largest area of rainforests in the world. These forests are quiet. inaccessible, and serve as a natural wildlife reserve. It is only here in the world that gorillas are found.
Other important animals are the elephant, hippopotamus, baboon, chimpanzee, okapi, wild buffalo, monkey, harmful tse- tse flies, poisonous ants, reptiles, crocodiles and the mamba-a dreaded poisonous snake.
Thousands of species of trees are scattered all over the forest. As a result, it is difficult to obtain timber or forest products from these forests.
Extensive tropical grasslands, known as ‘Savannas’ are found to the north, south, and east of the equatorial evergreen forests. As rainfall decreases, the dense rainforests gradually thin out and are finally replaced by tropical grasslands called ‘Savanna’ (From Spanish ‘Zavana’ meaning ‘a treeless plain’).
During the wet summer, the tall coarse grass of the Savanna is lush green but during the dry winter, they dry up and turn brown. This grassland, in some places, is dominated by very tall (3 to 5 m) ‘Elephant Grass’.
In general, the grassland is dotted with dwarf trees like the baobab, tamarind, and many species of acacia including the gum arabic of Sudan. For this park-like appearance, this type of vegetation is called ‘Park land’.
The Savanna is the home of Herbivorous animals, like deer, zebra, elephant, double-horned rhinoceros, and giraffes. Carnivorous animals, such as lions, leopards, and hyenas are common here. So Savana grassland is also known as the ‘Paradise of hunters’. Hippopotamus and crocodiles are found in the rivers.
This type of grassland is founds in the Southern parts of the African plateau. The grasses are softer, juicier, and shorter than that of Savanna. The grassland is known as ‘Veld’. ‘Veld’ comes from the African word ‘Veldt’ meaning ‘field’. The veld is used as an ideal grazing ground for cattle and sheep.
This type of vegetation is found on the eastern slopes of Drakensberg mountain along the eastern coasts of Mozambique, Tanzania, Kenya, Somalia of East Africa, and in Madagascar Island.
Owing to high temperatures and heavy rain (above 100 cm) that occur mainly in summer these areas have dense forests of tropical hardwood deciduous trees. Here, forests of sal and bamboo trees are found. The trees shed their leaves in the dry winter season due to a lack of moisture.
This type of vegetation is found in the Tell Atlas region along the coasts of the Mediterranean Sea in north Africa and the Cape Province on the southern coasts of South Africa. These places have long, hot, and dry summers and wet but short, cool winters.
So the warm temperate evergreen trees which grow here, have long roots to reach deep down into the soil. Their banks are thick and leaves are waxy or oily to prevent loss of moisture during the long dry summer. Cork oak, birch, mulberry, olive, fig, and citrus trees like orange and lemon are the important trees of this region and the vine is the main creeper.
Olives, lemons, and grapes are produced so much that the region is called the ‘Orchard of the World’. Cedar and cypress trees are found in higher altitudes.
There is very little plant growth in the hot and extremely dry desert regions of the Sahara in north Africa and the Namib and Kalahari in South Africa. In these regions, vegetation is very much scanty and comprises thorny scrubs.
Only drought-resistant plants like cacti, date palms, thorny bushes, and grasses grow here.
Grasslands are used as pastures where camel, sheep, and goats are reared. Camels are often referred to as the ‘Ship of the Desert’ because they are used as a carrier of people and goods.
In the highlands vegetation changes with an increase in altitude. Thus the major part of the mountainous region of East Africa has a cool temperate forest with upland pastures.
Ethiopian Highland and Mountain regions of southern parts of Africa are covered by coniferous trees and also broad-leaved forests. Giant trees like camphor, cedar, yellow wood, and also bamboos grow in East African highlands.
Introduction:
The Nile Basin is an important region of Africa. It is a fertile and green tract and has fostered one of the earliest civilization-the Egyptian civilization thrived in the Nile Basin. The Nile gives immense benefits to the countries through which it flows.
This is particularly true for Egypt and Sudan whose economy is greatly indebted to the Nile, without which rainless Egypt would have become a desert part of the vast Sahara.
Centuries ago the famous Greek historian Herodotus described Egypt as the ‘Gift of the Nile’. He was referring of course to the life-giving water and the rich silt that the Nile carries from equatorial Africa to the hot desert of Egypt.
Even today the river is the lifeblood of Egypt and the Nile Valley-largest oasis of the world in the heart of the Sahara.
Location:
The Nile, 6690 km long, is the longest river in the world and flows in Africa from south to north through the countries of Burundi, Rwanda, Tanzania, Zaire, Kenya, Uganda, Ethiopia, Sudan, and Egypt. But 75% of the Nile Basin lies in Egypt and Sudan.
The Area Of The Nile Basin :
The Nile Basin covers an area of 3.35 million sq. km ( a tenth of Africa)
The Course Of The Nile River:
The name ‘Nile’ is derived from the word ‘Nilus’ meaning ‘which source is unknown’. It is usually considered that the river ‘Kagera’ forms the headstream of the Nile. It rises near the northern tip of lake Tanganyika and flows west to meet lake Victoria, the largest lake in Africa.
The course of the river between lake Victoria and lake Albert is known as ‘Victoria Nile’ or the ‘Albert Nile’, and then as Bahr el-Jebel (the river of the mountain). Two tributaries of the river, the Bahr- el-Ghazal and the Sobat meet the Bahr-el-Jebel in the Sudd region at a latitude of about 10°N.
The former comes from the west and later from the east at Malakal and flows as the White Nile. The main tributary or another part of the Nile-the Blue Nile that supplies 70% of Niles’s flood water flows down from the south of lake Tana in the Ethiopian highlands.
The two rivers (The White Nile and the Blue Nile) meet at Khartoum (the capital of Sudan) and flow as the Nile. Between two rivers lies a vast flood plain called the ‘Gezira plain’.
Then the Nile flows northward through the desert belt of Sudan and Egypt, it receives its last tributary the Atbara. In this desert belt, the Nile flows through a narrow valley and over a series of six rapids, known as ‘Cataracts’ which make this section unfit for navigation.
The course of the Nile between Aswan and Cairo is actually, extended through the Egyptian Desert, the Delta course of the river the Nile starts from Cairo the Nile has divided into seven distributaries forming a large delta (the famous Nile delta) and finally discharges, its waters to the Mediterranean Sea.
According to the characteristics of the river course from the source to mouth, the Nile Basin can be sub-divided into the following parts:
The Nile Basin extends from 4° south to 32° North latitude thus covering a vast latitudinal extent of 36°. Hence the Nile Basin enjoys different types of climates:
Agriculture of the Nile Basin depends on irrigation water from the Nile. Basin irrigation has been in practice in the Nile Valley for the last 5000 years.
Other than this the Egyptian fellahin (Peasants) use water pumps and other methods such as Archimedean Screw, Shaduf (donga), and Saquia (Water wheels) to draw water from the canals and the river.
Sometimes irrigation is practiced through Persion wheels by lifting water collected in the depressions. The most modern method of irrigation is practiced by constructing dams across the Nile. Thus agricultural fields are irrigated throughout the year.
Dams and barrages constructed over the river Nile are-
75% of the Nile Basin lies in Sudan and Egypt. In Sudan, the world’s finest long-staple cotton is grown in the Gezira plain. Other crops grown here are dates, groundnuts, and millets.
The chief agricultural crop in the Egyptian part of the Nile Basin is long, silky cotton. ‘Egyptian cotton’ is famous for its high quality.
Egypt is the world’s major producer of long-staple cotton. Other crops are rice, wheat, sugar cane, corn, barley, sweet potatoes, millets, oat, ground nut, dates, tobacco, etc. Vineyards are common on the cooler Mediterranean coast to Alexandria.
The availability of fodders like berseem (Egyptian clover), alfalfa, etc., and the prevalence of fallow lands and the arid lands on the edge of the desert have made stock rearing an important occupation of the Egyptians. Sheep, water buffaloes, goats, donkeys, and camels are reared.
The Nile Basin is not so rich in mineral resources. But some minerals, such as Limestone, Manganese, Phosphates, Talc, Asbestos, Common salt, Mineral oil, Lead, etc. are found in Egypt and Sudan. Some minor deposits of gold, iron ore, and copper are found in the middle Nile valley i.e. in Sudan.
A number of industries have developed in Egypt and Sudan due to the availability of raw materials, sufficient supply of water, abundant labor, supply of hydroelectric power, etc. in the Nile Basin. Agro-based industries are well-developed.
Among the growing industries cotton textiles, sugar milling, wine and alcohol, and vegetable oil processing are important cotton textile is the principal industry of Egypt. The principal cotton textile center in Alexandria.
Other industries are woolen textile, leather, cement, fertilizer, oil refining, silk, rayon, and linen. Metallic industries have not developed here due to a lack of minerals. As the industries are fed by imported coal the concentration of modern industries is found in the cities, of Cairo and Alexandria.
The Nile is still the main highway of communication. The lower Nile below the first cataract at Aswan is fully navigable. Motor transport is also well-developed in the lower valley.
The Blue Nile and the White Nile river provide most of the transportation between the middle and southern areas of Sudan owing to the existence of five cataracts between Wadi Halfa in the Horth and Khartoum in the south a railway line has been constructed to establish links with Egypt.
In other parts of the Nile Basin also, roads and railways are spreading their network and gaining importance rapidly. Khartoum, Cairo and Alexandria have international airports.
The maximum population is found in the delta region of the Nile Basin. Due to developed agriculture, industry, and communication system benefits dense population occurs over the region where the density is around 1750 persons per sq. km.
Most of the Egyptians (80%) live here. The rest of the people live around the Oases. Recently a number of desert cities are being developed to attract people away from the overcrowded Nile valley.
Important cities and ports in the Nile Basin are Cairo, Alexandria, Giza, Port Said, and Port Suez of Egypt, and Khartoum and Omdurman of Sudan are worth mentioning.
Cairo:
The main city in the Nile Basin is Cairo (At Qahirah), the capital of Egypt, which lies where the Nile begins to spread out into a delta before entering the Mediterranean Sea. It is the most important city, a famous industrial and trade center.
It is the largest city in Egypt as well as the largest city in Africa. It is also the largest city of the great Sahara and the largest desert city in the world.
Alexandria :
Historically famous city Alexandria (Al-Iskandariya), is located at the extreme northwest of the Nile. Delta is the chief and the second largest city in Egypt as well as Africa. It was founded by Alexander the Great in 332 B.C./331 B.C. It is the most important industrial center of Egypt.
Giza:
The third largest city in the Nile Basin of Egypt is Giza. It is situated near Cario and is famous for the Pyramid and Sphinsk of Africa.
Port Said:
Port Said is a small but important port on the Mediterranean coast. This port of call for passenger steamers lies on the western part of the delta region of the lower Nile Basin.
Khartoum:
Khartoum (Al-Khurtum) is the capital and chief industrial town of Sudan. It is situated on the edge of the desert at the junction of the Blue Nile and the White Nile. It is also the major market center of Sudan.
Omdurman :
It is the sister city of Khartoum. It is also situated on the edge of the desert at the junction of the Blue Nile and White Nile.
Actually, Egypt is a rainless sandy desertic country occupying the eastern part of the Sahara desert. Annual rainfall is less than 25 cm. In such a dry environment agriculture is not possible.
The ancient people of Egypt relied upon the Nile to overflow its banks regularly every year. This left a flooded area covered with fertile soil. So, the crops that could be grown there helped to make Egypt rich and prosperous.
On this land irrigation from the river Nile allows agricultural production of crops throughout the year. The entire farming land of Egypt is located in the Nile river valley. Thus without the river Nile flowing through Egypt, the country would have remained only a desert.
But the river Nile has turned this desert into fertile green farmland by depositing its silts. Nile water also helps in the irrigation of this farmland. The irrigation still practiced in upper Egypt, gave birth to the ancient Egyptian civilization.
The Nile is the only transport or communication line extended from north to south. The greatest gift that the Nile was given and is still giving is the supply of drinking and industrial water. The river also has an important role to generate hydel power.
In this way, it seems that Egypt is blessed by the river Nile with its attributes. It has granted life in the desert country of Egypt. Hence the great historian Herodotus told-‘Egypt is the gift of the Nile’.
Introduction:
The Arabic word ‘Sahara’ means ‘desert’. The Sahara desert of Africa is not only the largest hot desert in the world but also it is the greatest of all deserts. Rocky hills, a vast expanse of sand striated by winds, folk tales of nomadic tribes walking across the desert with a caravan of camels-those are the essences of Sahara.
Location And Boundary:
The Sahara desert is located in north Africa. It extends from the Atlantic coast in the West to the Red Sea coast in the east and from Atlas mountain in the north to the Niger valley in the south.
Lybia and major parts of Egypt are located in this desert. Parts of countries like Algeria, Morocco, and Sudan. Tunisia, Spanish Sahara, Mauritania, Mali, Chad, and Niger are also included in the Sahara Desert.
Area And Extension:
The Sahara desert has an area of about 6.5 / 7 million square kilometers. The Sahara desert is so large that the whole continent of Europe or 21⁄2 Indias can fit into it. It stretches across northern Africa from the Atlantic Ocean to the Red Sea a distance of about 5600 km.
On the other hand, the breadth of the desert is about 1600 km from north to south. The average breadth of the desert is about 1270 km.
Relief Of The Sahara Desert:
The Sahara is almost a plateau desert. The average altitude is about 300 meters. The major Sahara ranges are the Ahaggar mountains of Algeria and the Tibesti massif in Lybia and Chad.
The Emi Koussi Volcano (3415 m) in the Tibesti is the highest point in the Sahara. To the northeast Quattara depression drops to 133 m below sea level.
This plateau desert region is composed of old rocks, exposed to erosion for a long time. Sand- dunes, pebbles, boulders, and bare rock stands have formed the relief of the Sahara.
Landforms of the Sahara Desert: The Sahara desert has three distinctive landforms-
1. Ergs:
An erg is a type of arid desert with an extensive cover of sand in the form of dunes and sand sheets, especially in the Sahara.
2. Regs:
In the eastern part of the Sahara desert, all the fine materials have been blown away and the surface is covered by pebbles and boulders. This part of the Sahara desert is known as ‘reg’ in Algeria and ‘serir’ in Libya.
3. Hammada:
In some parts of the desert, an extensive flat rocky surface is exposed from which sand has been removed by the wind. This desert surface of the bare rock is known as hammada.
Only the river Nile in the eastern part of the Sahara and the river Niger in the western part of the desert are flowing. Most of the rivers of the Sahara originate from Atlas mountain and the Central highlands.
But their channels have dried up as the water infiltrates into the sandy bed and excessive evaporation due to very high temperature. These dry river channels are wadis.
Wadis may experience occasional flash floods after heavy desert thunderstorms. There are many large or small wadis in the Sahara. They are dry for 340 days of the year. Several wadis in the northwestern Sahara are fed by rain and snow.
Lakes :
The important lake in the Sahara is lake Chad, which lies on the borderland of the Sahara. The lakes of the Sahara have no outlet and therefore are saline. They are not suitable for irrigation.
Oases:
A place in the desert that receives enough water to allow plants and crops to grow is an oasis. The most important places in the Sahara are the bases. Some important Sahara oases are Kharga and Farafra in Egypt, Khufra in Libya, and Ghardaia in Algeria.
Natural Vegetation:
The scarcity of water in the desert does not support the growth of vegetation. Only drought-resistant plants like acacia, and cactus, have thorny roots and thorny leaves. Usually, around the oases, these trees grow. Various salt-tolerant plants also grow in saline low-lying areas.
Climate In The Sahara Desert:
The Sahara is an arid land. The climate of the Sahara desert is the extreme type with scorching summers (50°C-52°C) and near-freezing winters (5°C -10°C).
Sometimes the day temperature during March to June rises above 54°C and at night, the heat rapidly goes out into a cloudless atmosphere and the temperature may fall below the freezing point.
So, the range of temperature is very high. The annual average rainfall is uncertain and less than 20 cm. Rainfall, besides being scanty, is spotty and undependable. In some places, years pass away without giving a single drop of rainwater.
World’s highest temperature and lowest rainfall have been recorded in this region. The highest temperature recorded in Summer is 58°C (The highest temperature in the world is recorded in ‘Al-Azizia’ of Libya) A terrible sky-blanketing dust storm and the sand storm may happen in the daytime, especially in the N.
Sahara, in summer. It is known as Simoom (Simoon) in’ the Arabic or local language. A hot dry southerly wind blows across Egypt and the South Eastern. The Mediterranean area from the Sahara.
It is called Khamsin. On the Guinea coast a west African hot and often dust-laden wind blows South East. from the Sahara.
It is called Harmattan. Its dryness helps to relieve the shifting humidity as it nears the coast and thus seems a relatively cool and healthy wind in that area, hence its local name there is ‘the Doctor’.
Animals:
Herds of camels, flocks of sheep, and goats are found roaming in the grasslands. The most popular cattle is a camel. Of all the animals the camel is ideally fitted for life in the desert.
The padded feet, fatty, hump, fewer Sweat glands, thicker artery walls, tough mouth with a long neck, hairy skin, and large eyelashes. The ability to close its nostrils makes this animal suited to live in the desert.
When alive, the animal supplies milk and carries people and goods. When dead, its flesh can be eaten, its hide can be used for making tents and bags, and its hair for making clothes and rugs. No wonder the Arabs regard the camel as the “Greatest gift of Allah”.
Agriculture:
The scarcity of water is the most important problem of the Sahara desert. Agriculture is only possible around the oases where the groundwater level is close to the surface. cotton, wheat, barley, millet, rice, potatoes, corn, sugar cane, vegetables, watermelon, ‘dates, and other fruits are mainly cultivated.
Minerals:
Mineral oil is produced in Algeria and Libya. A little amount of coal, salt, iron- ore, and gypsum are also available in the desert.
Industries:
The adverse physical environment and the lack of raw materials are responsible for the industrial backwardness of this region. Only cotton and woolen textiles, oil refining and. sugar industries have developed in some places of the Sahara desert.
Transport System:
The people of the Sahara desert still make journeys of hundred of kilometers so by camel. Camels are the main ride for the inhabitants of the desert. A herd of camels moving together in a desert is referred to as a ‘Caravan’. Caravans of camels cross the deserts along regular routes which are studded with oases.
They deliver news, exchange goods, and carry dates and hides to ports and cities. However, with the extension of the Trans-Saharan railway and the construction of metalled roads, the ‘ship of the desert’ as the camel is called, is gradually giving place to mechanized transport.
Changing Scenario:
The Sahara has changed with time. Rich oil and gas fields and some iron-ore, coal, rock-salt, phosphate, zinc, lead, and manganese fields have been discovered in different parts of Algeria, Libya, and Egypt. New industries are also being set up in different areas.
Thus many former nomads and oases dwellers now flock to the mines, oil refineries, iron and steel factories, and textiles mills for employment. So, the face of the Sahara and the life of its people have been changing fast in recent years.
Population:
The Sahara desert is, actually an uninhabited region. The Sahara with about 5 million inhabitants has an extremely low density of population-less than one person per square kilometer. Two groups of people live in the Sahara such as
1. The nomadic people are the Creda, Beduins (Dwellers of the desert), Chaambas, Berbers, and Tuaregs (the people of the veil). These nomadic people mainly rear sheep, goats, and camels and move from one place to another.
2. Some live in oases or on the highlands and desert margins where poor pastures are found. The larger oases have villages with their tall flat-roofed mud houses called adobes. These houses are built close together to save space.
Tripoli :
Tripoli is the capital, the largest city as well as the largest port of Libya.
Benghazi :
Benghazi is the second largest city and another important port in Libya. Algiers is the capital, largest city, and important port of Algeria.
Timbuktu (Mali), Awburi (Libya), Hassi Massaud, and Bechar (Algeria) are important commercial centers.
The continent of Asia is the largest and most populous continent in the world. The word Asia is derived from the word ‘Asu’. The meaning of this word is ‘east’ or ‘the land of the rising sun’. It contains 33 per cent of the world’s land surface and occupies four-fifths of the Eurasian landmass.
About 60% of the total population of the world lives here. Asia is the most diverse of all continents. The variety of landforms, rivers, climates, natural vegetation etc. is infinite on this continent.
The linguistic, ethnic and economic diversity of Asia is greater than that of any other continent. Politically, it has the most varied forms of government.
Asia is the cradle of some of the most ancient civilizations in the world which are associated with its long, navigable rivers é.g. the Indus valley civilizations, and the Mesopotamian civilization of the Tigris.
Euphrates and the Chinese civilization of the rivers Hwang-Ho, Yangtze-Kiang and Si-Kiang.
Read and Learn More WBBSE Notes for Class 7 Middle Class Geography
Asia because of its size, location, extent, and relief is characterized by contrasts in its climate, natural vegetation and other geographical factors and hence is spoken of as the Continent of Contrasts. Asia is also known as the Continent of Extremes.
Location:
The continent of Asia mainly occupies the northern part of the Eastern Hemisphere.
In latitude, it extends from nearly 82° North to nearly 10° South and in longitude from 26°04′ East to 169°40′ West approximately, if the Cape Chelyuskin Island and Severnaya in the Arctic Ocean and the South-East Malaysian-Indonesian Archipelago are included.
” class 7th geography chapter 9 life in the desert”
It extends over a latitudinal range of 92° from North to South and a longitudinal range of about 165°.
The continent is bounded on the north by the Arctic Ocean, and on the east by the Pacific Ocean and its associated seas. On the west Asia and Europe form a continuous landmass and the boundary between them is rather difficult to define.
It is marked by approximately the crest of the Ural Mountains, the Ural River, the Caspian Sea and the Caucasus Mountains.
Then it continues southward. the Black Sea, the Sea of Marmara, and the Aegean Sea. The country of Turkey lies partly in Europe (7%) and (93%) in Asia, on both sides of the narrow Straits-the Bosphorus and Dardanelles.
One-third of Russia (CIS) lies in Europe and the rest in Asia. Along the coast of Asia Minor (Turkey) with the Mediterranean Coast of the Levant forming Asia’s Western limits.
In the South of Asia lies the Indian Ocean and the associated Seas. Asia was connected with the continents of Africa by the Isthmus of Suez separating the Red Sea from the Mediterranean Sea.
class 7th geography chapter 9 notes
In 1869, a Canal, known as the ‘Suez Canal’ was cut through this isthmus; this joined the Mediterranean to the Red Sea and separated Asia from Africa.
In the northeast corner lies the Bering Strait between Asia and North America. With the exception of New Guinea and the Aru Islands which belong to Oceania, the island of east India is considered as part of Asia.
Area:
The total area covered by Asia is about 44579000 sq. km. This is almost one-third of the total landmass of the world. It is one-seventh larger than the two Americas together, twice big as Africa and four times the size of Europe.
Extension:
The maximum length is 10780 km and the greatest width is 8530 km. The mainland of Asia is so compact that a considerable area in the central part of the continent is more than 2400 km away from the nearest Sea Coast.
Population:
Asia is the most populated continent in the world. These are nearly 417 crores of people (4164252000) (July 2011). 60% of the total population of the world lives here.
Asia is a typical continent exhibiting different types of natural and socio-cultural features. Some major features are described below:
Asia is also developed in agriculture and industries. The linguistic, ethnic and economic diversity of Asia is greater than that of any other continent.
” life in the temperate grasslands class 7 pdf “
Asia is known as the ‘Continent of Extremes’ because there are some specific extreme characteristics found in Asia.
Asia is the largest continent in the world. It is also the most populated continent in the world. The highest mountain (in the Himalayas), highest mountain peak (Mt. Everest 8848 m),.
highest plateaus (The Pamir, ‘Roof of the world’), the largest high plateau Tibet, the largest lake in the world (Caspian Sea), the deepest lake in the world (Baikal), the lowest point of the land surface (Elghar valley of the Dead sea which is 393 m), coldest place (Verkhoyansk,- 56°C).
The Omiyakon in Siberia – 72° C, one of the hottest places in the world (Jacobabad; 52°C), the rainiest Cherapunji area (Mowsynram, 1254 cm), the largest peninsula in the world (Arabian Peninsula, 3250000 sq. Km) and the largest strait in the world (Malacca), the largest continental shelf (the Sunda platform), the deepest trench Mindanao Deep (Mariana trench – 11034 m)-all are situated in Asia. Such extremes make the continent of Asia the ‘Continent of Extremes’.
Asia, because of its size. location, extent and relief are characterised by contrasts in its climate, natural vegetation and other geographical features, Asia has rightly been called the ‘Continent of Contrasts’.
All the above factors clearly establish Asia as the ‘Continent of Contrasts’.
“class 7 geography ch 9 notes “
Asia is a vast continent which represents all the major landforms. On the basis of physiography, Asia is divided into seven divisions. They are as follows:
The Northern part of the continent of Asia has a triangular-shaped plain of extensive flat land which occupies almost 40% of the continent.
It stretches from the Ural Mountain and the Caspian Sea in the west and southwest to the Yablonoy, Stanovoy and Verkhoyansk Mountains in the northeast. This northern plain of Asia is the largest plain in the world.
This extensive region can be further divided into three parts. They are-
Siberian Shield:
The Siberian shield stretches from the Bering strait in the east to the banks of the Yenisey river in the west. It is a very ancient and denuded surface which is formed due to the gradual erosion of old plateaus.
The Western Siberian Plain:
It stretches from the valley of the Yenisey river in the east to the western boundary of Asia in the west. The average height of the plain is 200 m. In this region between the Ob and the Yenisey rivers lies an extensive marshy lowland.
Lowlands Of Turan Basin:
The lowlands in the Southwestern parts of the northern plains, an area of inland drainage, the Amu Darya and the Syr Darya. Both of them flow to the Aral Sea, and other to the Caspian Sea.
At the continent’s heart or nearly the centre of Asia lies a convergence of the world’s mightiest mountains, like the Himalayas, Karakoram, Hindu Kush, Kunlun etc. So, Asia is also called the ‘Mountain hearted continent’.
In between the mountains be some famous plateaus. Most of the mountains extend from two centres or knots called
Pamir Knot:
The vast mountain system of Asia meets at the Pamir knot. To the north of Jammu and Kashmir state of India lies the world’s highest plateau-the Pamir
Nearly 4800 m high the Pamir is also called the ‘Roof of the world’ because it comprises a great mass of mountains with lofty plateaus (3600 – 4200 m).
As the roof is the highest flat surface of a building so also the highest flat surface or plateau. on the Earth is the Pamir and hence is so-called. Most of the main mountain ranges of Asia. radiates long distances from the Pamir Plateau, so it is also called the ‘Pamir Knot’.
South-east of the Pamir extends the Himalayan Range. Himalaya is the largest and highest mountain in the world.
Mt. Everest is the highest peak in the Himalayas (8848 m) and also the >world. Further North of the Himalayas lies the Karakoram Mountain range. The highest peak of the Karakoram range is Godwin Austin or K2 (King of Karakoram).
It is the 2nd highest peak in the world (8611 m). East from the Pamir extends the Kunlun, Altyn Tagh, Nan-shan, Siniling- shan and Khingan Mountains.
Stretching northeast from the Pamir, extend the Tien-shan, Altai, Sayan, Yablonovoy and Stanovoy Mountain ranges. West of the Pamir extends the Hindu Kush mountain range and South-west of the Pamir knot extends the Sulaiman and Kirthar mountain ranges.
Further west it forms the Zagros mountain which merges with the Armenian Knot.
Armenian Knot:
This plateau or knot is located to the southeast of the Black Sea. To the east of this knot extend two mountains-Zagros and Elburz and to the North-west of this knot extend two Mountains-Pontic and Tauras.
Between these two ranges lies the Anatolia Plateau, called ‘Asia Minor’. The Caucasus range belongs to Europe.
The Central Asiatic Plateaus:
The vast plateaus lie between the folding mountains and the northern plains. The plateaus of outstanding importance are as follows.
The Plateau Of Tibet:
This is the largest plateau in the world and it is surrounded by great Himalayas to the south and Kunlun to the north.
The Plateaus Surrounding The Tarim Or Sikiang Basin:
The Tarim basin is one of the driest basins in the world. It is surrounded by Tien Shan to the north and Altyn Tagh to the south. This basin is largely occupied by the Takla Makan Desert.
The Tsaidan Basin:
This basin lies between Kunlun in the south and Nanshan in the north.
The Plateau Of Gobi Or Mongolia :
This plateau is a stony desert and lies between Altai and Nanshan ranges the average height varies from 1000 metres to 1500 metres above sea level.
Plateau Of Iran:
This plateau covers really whole of Iran. It is situated between Elburz and the Hindu Kush to the north and Zagros to the south.
Plateau Of Anatolia:
The plateau of Anatolia lies in the central part of Turkey. It is bounded by Pontic to the north and Tauras to the south.
The Sistan Plateau:
The Sistan Plateau of Afghanistan lies between the Hindu Kush Mountain in the north and the Sulaiman Mountain in the south.
The plateau of central Asia is surrounded by mountains so most of them are dry with little vegetation, i.e. nearly like deserts or actual deserts. This area is also called the “Dead Heart of Asia”.
It is mainly a highland region including high ranges around the Verkhoyansk and Kolyma tablelands. The Mountains of Kamchatka and Sakhalin constitute comparatively young parts of the Pacific ocean mountain belt.
They have numerous extinct active volcanoes. The mountainous islands of Kuril Arc are an extension of the Kamchatka mountains.
The northeastern highland region can be traced even to the isolated ranges north of the Tien-Shan. There are the Yablonoi-Stanovai and the extensive Altai-Sayan mountain stand.
Along the southern shore of Lake Baikal lie the Sayan mountains. The ranges of the east are the Khingan mountains and the Shanshi highlands.
The old plateaus of South Asia can be divided into three sections-
The Plateau Of Arabian Peninsula :
The Arabian Plateau is situated in South-west Asia. This plateau is not much broken up. Its steep edge lies on the west towards the Red Sea.
It slopes on the northeast towards the Tigris-Euphrates valleys. The whole region is dry and it is entirely a desert land without lakes and rivers.
The Deccan Plateau Of Peninsular India:
It is the oldest part of Asia and one of the most stable landmasses in the world. The whole terrain is made up of several large or small plateaus forming into a dissected plateau.
The undulating surfaces with broad, rounded summits seldom rise above 600 m. constitute important physiographic uniqueness of the area.
The-Shan-Yunan Plateau Or The Plateau Of Indo-China:
It includes parts of the Shan state of Myanmar and the Yunan state of China. Towards the south, it extends up to the Malayan peninsula. It is, a dissected plateau broken by the rivers like Salween, Mekong and Upper Yangtze.
The great lowlands of Eastern Asia and Southern Asia are mainly the river plains or the alluvial plains. These plains are fertile and the most densely populated areas. Some of the most important river valleys are as follows:
Asia is bounded by the Arctic Ocean to the north, the Pacific Ocean to the last and the Indian Ocean to the South and has numerous seas, bays and gulfs which are of strategic importance.
To the northeast and south, this continent has coastal plains that vary from being very broad in some places while at others it is narrow. Many places are fertile and cultivable but some parts are salty and sandy. So these plains are not suitable for cultivation.
Asia has a large number of islands. There are some isolated islands and some groups of islands in the Pacific Ocean in the east and south-east of Asia like-
The continent of Asia contains a large number of rivers. Of the world’s ten longest rivers, six are in Asia. The characteristic features of the rivers or drainage system of Asia are as follows:
Important Rivers Of Asia
| Type of the Rivers | Name of the Rivers |
| 1. North-flowing Rivers | Ob, Yenesei, Lena, Khatanga, Kolyma |
| 2. East-flowing Rivers | Amur, Hwang Ho, Yangtze-kiang, Si-kiang |
| 3. South-flowing Rivers | The Ganges, Brahmaputra, Indus, Mekong, Menam, Irrawaddy, Tigris, Euphrates |
| 4. Inland Rivers | Amu Darya, Syr Darya, Alli, Tarim, Ural, Luni, Helmond, Jordon |
| 5. Wesfflowing Rivers Narmada, Tapi | Narmada, Tapi |
Ob, Yenesei, Khatanga, Kolyma etc. are the main river falling into the Arctic Ocean. The characteristics of these rivers are as follows:
Ob:
The mainstream of the Ob (3677 km long, with Irtish 5570 km long) rises in the Great Altai Mountains and flows to the north. The Irtish, its principal tributary, is longer than the mainstream before their confluence.
Ob along with Irtish is the 2nd longest river in Asia. The river flows very sluggishly over the flat West Siberian Plain and falls into the Arctic Ocean (the Gulf of Ob).
Yenesei:
Yenesei (5540 km) is coming out from the Sayan Mountains flows towards. north and falls into the Arctic Ocean (Yenesei Gulf). Its main tributary is the Tungaska. Yenesei is the 2nd longest river in Asia and the 5th longest river in the world.
Lena:
Lena (4270 km), rises from the mountains adjacent to Lake Baikal and flows to the north into the Arctic Ocean (Laptevic Sea). Vitim and Aldan are its two main tributaries.
Khatanga:
It is coming out from the Sredne Highland, flows north and falls into the Arctic Ocean. Kheta is its main tributary.
Kolyma:
It is coming out from Khrebet Cherakogo (Gida Mountains) high land flows north and falls into the Arctic Sea. Omoloki is its main tributary.
The Amur, Hwang-Ho, Yangtze-Kiang and Si-Kiang etc. are the main rivers of Asia that flow to the east and drain into the Pacific Ocean at different parts. The characteristics of these rivers are as follows:
The Amur (4440 km):
The Amur coming out from the Yablonoy Mountains flows towards the east and falls into the Pacific Ocean (Okhtosk sea).
The Hwang-Ho (5460 km):
It rises from the north of the Bayanhar Mountains lie in the Ching-hi state of China and flows to the east and falls into the Pacific Ocean (the Bay of Po-hai). Large amounts of less are lifted from the Gobi desert of Mongolia and deposited in the Hwang-Ho river by the wind.
The loess is yellow in colour and when carried by the Hwang-Ho, the river looks yellow. Therefore the Hwang-Ho is also called the ‘Yellow River’. The river was known as the ‘Sorrow of China’ as it used to create floods each and every year.
But now it is not all known as the ‘Sorrow of China’. The river has been dumped in several places and thereby providing irrigation facilities to a vast region. Its main tributaries Phen-Ho and Wei.
The Yangtze-Kiang:
Yangtze-Kiang is the longest river 5590 km/6300 km in China. It is also the longest river in Asia as well as the third longest river in the world: Yangtze-Kiang means, the ‘son of the ocean’.
It is also known as the river of ‘Golden Dust’. It is coming from the Geladangdong mountain peak in the south of Kunlun mountain flows towards the east and falls into the Pacific Ocean (North China Sea).
The Si-Kiang (2340 km):
The Si-Kiang rises from the Umang mountain region of the Yunan plateau (Yunan Province of China). It flows towards the east and finally falls into the South China Sea. Peikiang is its main tributary.
The lower course of this river is known as the Canton river as the 2nd largest city and port in China, Canton is situated on the bank of the river. The river is also known as the ‘Pearl river’ in China.
The Ganges, Brahmaputra, Indus, Mekong, Menam, and Irrawaddy. Tigris, Euphrates etc. are famous rivers. The characteristics of these rivers are as follows:
The Ganges (2510 km):
The Ganges is the longest river in India. It rises from the Gangotri Glacier of the Himalayas. It is the confluence of two river-Alakananda and Bhagirathi. The combined river cuts through the Himalayan Ranges and debouches to the plain near Hardwar.
It then flows southeast through the north Indian plain and finally divides into two branches near Rajmahal hill. The main eastern branch (the Padma) enters Bangladesh and the slender western branch (the Bhagirathi) flows through West Bengal and falls into the Bay of Bengal near Sagar Island.
The main tributary of the Ganges is Yamuna. The Ganges- Brahmaputra Delta is the largest delta in the world.
Brahmputra (2580 km):
It rises from the Chemaung-dung glacier of the Tibetan plateau. flows towards the cast. Around Namcha Barwa the river turns southwards, enters India and then turns westwards.
To the west of the Meghalaya plateau, it again turns southwards to meet the Ganges near its mouth before entering the Bay of Bengal. Majuli Island in the River Brahmaputra is the largest river island in the world.
The Indus (2880 km):
It rises near Manas Sarovar lake in Tibet and then flows to the northwest and around Nanga Parbat, it turns to the southwest to finally drain into the Arabian Sea. Its main tributaries are Jhelum, Chenab, Ravi, Sutlej, Beas etc.
Mekong (4350 km):
It is the main river of Indo-China. It rises from the southern slopes of the Kunlun mountains and flows along the eastern boundary of Thailand before draining into the South China Sea.
Menam (365 km):
The river rises from the Shan plateau of Myanmar and flows to the south into the Gulf of Siam.
Irrawaddy (2090 km):
The river rises from the northern highland of Myanmar flows towards the south and falls into the gulf of Martaban. It is the main river of Myanmar. The main tributary of this river is Chindwin.
Tigrese (900 km) And Euphrates (2780 km):
These two rivers are rising from the Armenian plateau, and flow south through Iran and Iraq. The joint flow of these two rivers is known as ‘Sat-el Arab’ and then flows into the Gulf of Persia.
There are some inland rivers in Asia. Among these rivers Amu Darya, Syr Darya, Illi, Tarim, Ural, Jordon, Helmond, and Luni are mentionable. The characteristics of these rivers are as follows:
Amu Darya ind Syr Darya :
These two rivers are coming out from the Pamir plateau flow towards the northwest and fall into the Aral Sea.
IIIi:
It is rising in the Tien Shan Mountain region flows north and falls into the Balkhas Lake.
Tarím 1600 km:
The Tarim river is the world’s largest inland river. It rises from Karakoram Mountain and falls into Lop Nor Lake. This river has formed the Tarim basin. It is a non-perennial river.
The Ural:
It rises in the Ural mountains flows towards the south and falls into the Caspian Sea. The Helmond: The Helmond river rises in the Hazaragat Highland in Afghanistan flows towards the west and falls into the Hanun-I-Helmond Lake.
The Jordon:
Jordon is a small river. It rises from the Lebanon Highland flows through Jordon Valley and falls into the Dead Sea. This river remains dry throughout the year because of Scanty rainfall.
Luni :
This river is coming out from the Ana Sagar Lake of Aravalli Mt. flows towards the southwest and falls into the Rann of Kutch.
There are few major west-flowing rivers in Asia. Among them the Narmada and the Tapti (Tapi) are noteworthy.
Lakes Of Asia:
There are numerous lakes and marshes in Asia. Among them, some lakes have fresh water that is drinkable while others have salt water.
Freshwater Lakes In Asia:
The largest freshwater lake in Asia is Lake Baikal (Baykol) in Russia. It is the world’s deepest lake (1637 m below sea level). The other freshwater lakes are Manas Sarovar in Tibet, Dal and Wuler lake in Jammu and Kashmir, Nainital, in India, and Beuya Lake in Japan.
Saltwater Lakes In Asia:
The Caspian Sea (The largest lake in the world), Aral Sea, Balkhas, Dead Sea, Lop Nor (China), the Van lake of Turkey etc.
The climate is a very important element of the natural environment. The continent of Asia is so large that almost all the climatic types of the world are found here.
Causes or Factors of Diversity of the Climate in Asia: Enormous size, shape, compactness, range of latitude, latitude and alignment of mountains, direction of winds, and ocean currents combine to produce great climatic contrasts in Asia.
Factors affecting the climate of Asia are as follows:
1. Latitudinal Factor:
The continent of Asia lies between 82°N and 10°S latitude. The latitudinal range is 92°.
So the northern part of this continent is in the Arctic or north polar region (Frizid zone), the central part is in the Northern temperate zone and the southern part (Equatorial region) is in the torrid zone. Sun’s rays are oblique as we move away from the Equator.
As a result of average annual temperature gradually decreases from the Equator towards the Poles.
2. Altitudinal Factor:
Temperature decreases at a rate of 6.4°C with every 1000 m or 1 km rise in altitude. The average altitude of the Central Highlands of Asia is more than 4000 m High. So there is a difference in temperature in the lofty peak region and base region of a mountain.
3. Continental Location Or Distance From The Sea/Ocean:
One-third of this continent is nearly 1000 km from the sea and some part is near about 2400 km from the nearest sea coast.
The moderating influence of the sea does not reach the interior of the continent, so extensive areas in the central region have extreme climates.
4. Topogrophy/Presence Of Mountains And Plateau:
High mountains of this continent remain covered with snow and the intermontane plateau experienced extreme climate
For example, the great Himalayan Mountains act as a barrier to the influx of cold north wind to South Asia and the warm, rain-bearing south or south-west winds to the heart of Asia.
5. Direction Of wind:
Directions of winds are particularly important in Asia. In summer moist monsoon winds from the south come from the Indian Ocean and give plenty of rainfall to the southern region of Asia.
In winter the monsoon winds outflowing from land to sea are dry and cause Asia to be rather rainless.
6. Ocean Current:
According to the high latitudes that cross the northeastern coast of Asia, the region should have a cold climate.
But the warm ‘Kuroshio’ ocean currents flow along the shores of the area, so this part of Asia has a temperate climate occurring over the region.
Temperature:
In summer temperatures are very high from Arabia in the west to the northwest of India in the east. Temperatures vary from 32°C-38°C in the region in July.
The average temperature in the summer season in the un limit of Asia is 7°C on average. The southern part of Asia has the highest temperature in winter.
In January the temperature varies between 20° to 27°C. Further north temperature decrease In Siberia and far east at many places temperature fall below freezing point in January -30° to 40°C.
Air Pressure And Winds:
Extremely high temperature in summer in the tropical region, especially in northwest India creates a severe low-pressure belt over the region.
During the same season, there is high pressure over the India ocean, so winds carry plenty of water vapour from above the ocean and move into the low pressure over the northwest of India.
During winter the extreme cold in central and northern Asia causes high pressure over the region. Cold and dry winds then move from this high pressure in central and northern Asia to move to the low pressure in the south and east.
Rainfall:
During summer the monsoon winds blowing from the Indian and pacific ocean towards the mountain region of central Asia are moist and causes abundant rainfall in Southeast Asia (including India and China).
Rainfall is over 100 cm on average. The highest annual rainfall. in the world occurs in India in the state of Meghalaya at Mowsynram near Cherapunji.
It is nearly 1250 cm. Central Asia is surrounded by mountains, and the plateaus in the centre receive the least rainfall, 25 cm on average.
In winter the winds blow from land to sea. These winds are dry since they blow from the land. So most of Asia receives very little rain in the cold season except the west.
Being situated in the equatorial region temperature and rainfall over the East Indies (Malaysia and Indonesia) remain uniformly high throughout the year.
Some rain occurs along the Mediterranean coast and the influence of westerly winds. In Japan, the southeast coast of India northwest India etc. receives some rain.
| Climatic Type/Region | Location | Characteristics |
| 1.Equatorial climate. | The Equatorial type of climate is located between 5° S to 5° N parallels of latitude. It is observed in different countries of Asia such as Maldives, Sri Lanka, Singapore, Indonesia etc. | 1. Hot and Humid climate, 2. High-temperature throughout the year as the Sun’s rays fall vertically. 3. Very low-temperature range between 2 and 3° C. 4. Average annual temperature is in between 25° to 30° C. 5. Conventional type of rainfall occurs every afternoon throughout the year. Annual rainfall is 200 to 250 cm. 6. On account of marine location temper nature remains uniform deviating little from 27° C and is well distributed |
| 2. Tropical Monsoon climate. | This type of climatic region covers India, Bangladesh, Pakistan, and Myanmar. Laos Cambodia, Vietnam, Southern China and Japan. | 1. This type of climate is greatly influenced by 2-monsoon winds. 2. An important characteristic of this climate is the cycle of seasons. 3. Summers are hot and humid while winters are mild and dry. 4. Summer temperatures vary between 30°C – 32° C while in winter they are 18°C- 22°C. 5. Annual rainfall varies from 100 to 200 cm. |
| 3. Warm temperature or Type of climate. | This type of climate is found in the north and central parts of China and in some parts of South Korea and Japan. Warm temperate or China type of climate. | 1. Summers are mild with an average temperature being 27° C. 2. Winters are quite cold with temperatures between 4°C to 12° C. 3. Snowfall occurs in some places. 4. Summers are moist and winters are dry. 5. Annual rainfall on average is about 100cm occurs in summer due to Monsoon. 6. In summer typhoons or severe cyclones cause rainfall. |
| 4. Manchurian type of climate. | It extends over Manchuria to North and South Korea, Sakhalin. the island of Russia and the northern part | 1. Milder summers and more severe winters than China’s type of climate. 2. Moderate rainfall occurs in summer. 3. Sufficient snowfall occurs In winter. |
| 5. Hot Desert type of climate | The Tropical hot deserts type of climate is found in Saudi Arabia. Iran. Iraq. Pakistan. India (Thar) etc. | 1. The summers are dry and hot. 2. Sometimes temperature rises 48° to 5o°c. 3. Range of temperature is very high. 4. Rainfall is very scanty and less than 25 cm. |
| 6. Mid-Latitude Desert type of climate. In Asia, this type of climate is further divided into the following groups: 1. Tibet type. 2. Iran type. 3.Gobi type 4.Turan type | 1. Tibet’s type of climate is found on the plateau of Tibet, 2. Iran’s type of climate is found in the enclosed of Iran. 3. Gobi-type climate is found in the Gobi desert and desert area of Tibetan Highlands. 4. Turan-type climate is found mainly in southwest Siberian lowlands around the Aral Sea and Afghanistan. | 1. Summers and hot and dry, Temperature often reaches up to 37° C. 2. Winters are cold. 3. The annual and diurnal ranges of temperature are high. 4. The rainfall is very scanty. So mid-latitude deserts are found in continental interiors. 5. The rainfall occurs mainly in early summer and spring. 6. Amount of rainfall is about 30 cm |
| 7. Mediterranean type of climate. | This type of climate is found In Turkey, Syria, Lebanon Jordon, Israel, and parts of Iran and Iraq. | 1. The main characteristics of this climate are dry summer and wet winter. 2. Cyclonic rainfall ISO cm to 100 cm) are common. 3. Temperature varies from 20°C to 28°C. The range of temperature is not high. Day temperature sometimes exceeds 32°C. The temperature drops sharply at night because of the clear sky. 4. The long summer days have clear blue skies. |
| 8. Continental type of climate. This region comprises steppes and west Manchurian type of climatic regions. | It includes all the plateaus of central Asia surrounded by mountains {the Anatolian plateau in the west, the Kirghiz arc in the middle and the Gobi desert in the east. | 1. Short duration of summer and long duration of winter are the main characteristics of this climate. 2. The annual and diurnal range of temperature is very high. 3. Some rainfall occurs in summer and snowfall occurs in winter. 4. The amount of rainfall ranges from 25 to 75 cm. |
| 9. Cold-Temperate or the Taiga type of climate. | This type of climate is found between Tundra to the north and Steppe to the south in a narrow belt, also known as a Siberian type of climatic region. | 1. In this region winters are very severe and prolonged particularly in Siberia where the temperature is below the freezing point. 2. Summers are pleasantly warm and the average temperature is about 18°C. It rises occasionally up to 35°C and 40°C. 3. This causes a very high range of temperature. 4. The rainfall is scanty, between 30 cm to 60 cm. 5. Winters face heavy snowfall and frozen lakes and rivers. 6. On the whole winters are long and cold and summers are short and warm. |
| lO.Tundra type of climate. | In the northern border of Asia, north of the Arctic circle (66½° North) this climate occurs. The region lies in Russia. | 1. Winters are long and very severe with a long duration of darkness while the summers are brief and cool (O°- 10°C). 2. Then winters bring Icy cold winds (blizzards) and so it is very cold. 3. Annual rainfall, though a major amount in the form of snow is about 25 – 30 cm. |
| 11. Mountainous type of climate. | This type of climate is found in the central highlands of Asia. | 1. Temperature decreases with increasing altitude. 2. Rainfall is higher on the windward side than on the leeward side. 3. The high altitudinal regions’ temperatures are lower than the low altitudinal region. |
Natural Vegetation:
Plants that grow naturally in nature, without any human help, are called natural vegetation. This natural vegetation can form forests or jungles.
Natural vegetation is closely related to climate. Variations in temperature and rainfall cause variations in the growth of plants.
Asia being a large continent great variation in climate causes variations in the distribution and type of natural vegetation. Almost all types of natural vegetation grow in Asia. The natural vegetation of Asia can be classified into the following Natural Vegetation Belts of Asia.
1. Equatorial Evergreen Rain-Forests:
These dense evergreen forests are in the equatorial region due to high temperatures and rainfall. In Asia, these forests are found in Indonesia, Malaysia, Sri Lanka, etc.
Luxuriant forests of multiple species of very tall trees (about 45 meters) struggle towards the sunlight forming a thick canopy arrangement. They yield tropical hardwoods.
The principal trees are Mehogony, Rosewood, Ironwood, Teak, Ablus, Rubber, Cocoa, Cinchona etc. There is a thick undergrowth of numerous epiphytes.
At the ground level saprophytes are found in numerous varieties. This thick growth makes the commercial exploitation of the forests very difficult.
2. Tropical Monsoon Forests:
This is a typical forest, found in regions of monsoon climate. Due to humid summers and dry winters, both green and deciduous trees grow in this region. These forests are found in northern Malaysia, Thailand, Kampuchea, Vietnam, Laus, India, Pakistan, Bangladesh, Myanmar and South China.
In the areas having more than 200 cm rainfall evergreen forests are found, and the lands which get rainfall between 120-200 cm have deciduous monsoon forests. The principal trees are Mango, Mahogany, Ablus, Sal, Teak, Bamboo, Banyan, Peepul etc.
On mountains are found mixed types of deciduous vegetation and on coastal lands mangrove trees.
3. Sub-Tropical Mixed Forests:
These are so-called because of the admixture of deciduous trees with the majority of evergreen trees. One important aspect of these forests is that they marge into grasslands, both tropical and temperate and form parts of the ‘Pask land’ aspect of the grassland borders.
The evergreen trees decrease in number as one advance from coastal lands into interior parts. The deciduous trees occur equatorward and evergreen poleward. These forests are mainly found in northern Myanmar, southern and central China and in southern Japan.
The trees range from bamboo, palm, laurel, and beech as deciduous varieties. Important evergreens include chestnut, oak, camelia, and magnolia.
4. Temperate Mixed Forests:
These forests have two main characteristics. Firstly, the trees, are of mixed variety-deciduous and coniferous. Deciduous trees like oak, ash, alder, chestnut, and beech are a response to a temperate moist climate.
Theconferious trees like spruce, larch, silver fur and red pine are adapted to mountain regions like Hanshu Island of Japan. These mixed forests occur in North China, Manchuria, Central and northern Japan and in the adjoining areas.
5. Mediterranean Forests:
These forests are found along the Mediterranean coastal lands mainly in Israel, Syria, Lebanon and Turkey. Most plants like vines and chestnuts have long roots and others like citrus fruits trees have waxy leaves; others like olive small leave.
A number of citrus fruit-bearing trees such as Olive, Grapes, Lemon, etc. and other trees such as Cork-Oak, and some bushes such as Laurel, Lavender, Rosemary etc. grow here.
6. Steppe Grasslands:
In the mid-latitudes in the interior of the continent extending from the west to Manchuria in the east covering southwest Siberia, fringes of the Mongolian plateau and lowlands of Manchuria are extensive areas of grasslands known as ‘Asian Steppes’.
The steppes of central Asia are very dry and they get scanty rainfall ranging between 30 – 50 cm received mainly in summer. Most people lead a nomadic mode of life.
They are found in the Kirghiz steppe and Manchurian lowlands. Northward these grasslands form a ‘parkland’ with coniferous forests and southward they border the desert areas.
7. The Cool Temperate Or Evergreen Coniferous Forests Of Taiga :
These forests are found in high latitudes and mountain slopes. Their climate is characterised by cool Temperate Continental (Siberian) Climate and they are located South of the Tundra region. In Asia, these forests cover the areas of northern Russia including Siberia and Sakhalin.
The evergreen coniferous forests are of moderate density with little undergrowth and are in pure stands (a single type of forest). The trees are conical in shape to prevent the accumulation of snow on the branches and have small, thick, leathery needle-shaped leaves to check excessive transpiration.
Pine, fir, spruce, larch, hemlock, and cedar are common trees. The Taiga forest of Russia is the largest coniferous forest in the world.
8. Desert Vegetation :
The hot deserts in South-west Asia are also not without vegetation. There are of course spiky grass, dwarf bushes, and prickly plants. The vegetating corner of the continuous type is mostly found near or around the oasis.
Tall trees like dates and palms may also be found there. The clumps of leafless thorny perennials and others with stunted growth resist evapo transpiration. Cacti and in fact all the thorny bushes are among such plants grown in the desert.
9. Tundra Vegetation:
The Tundra Vegetation belt extends in a narrow belt north of the Arctic circle and along the northern shores of Asia. Winters are long (8-9 months) and very severe. So the Tundra is a result of excessively cold, strong winds and permanently frozen subsoil.
During the summer of 2-3 months willows and dwarf shrubs exist in favoured brutalities. The south-facing slopes exhibit in summer a short-lived splendour of flowering herbaceous plants. Moss, lichen, algae, sedges and bright Arctic flowers brighten the landscape.
The Yangtze-Kiang basin of China is drained by the river Yangtze-Kiang and its tributaries. Yangtze-Kiang is the third longest river in the world, after the Nile and Amazon rivers. The Yangtze- Kiang is the longest river in China as well as the continent of Asia.
The river originates from a glacier lying southwest of the Geladandong peak of the Tanggula Mountain in Qinghai province and flows eastwards to meet the East China Sea.
From the source to the mouth, the river extends for nearly 6300 km, covering a basin with an area of 1807199 square kilometres. Near the mouth, the river has formed a huge delta.
Importance of Yangtze-kiang Basin:
Yangtze-Kiang is not only the longest river in China but also the most important of all rivers. The river plays an important part in the economy of the country. The river basin is a fertile and multi-cropping zone. A large number of food and cash crops are raised.
The basin is one of the largest producers of rice. In China, 70% of the rice production occurs in this region and nearly 50% of all other food grains are produced here. So this river basin is called the “Granary of China” or the “Rice bowl of China”.
Sericulture is an important occupation of the people of this region. A large proportion of the mineral wealth and industrial products are also produced in this region.
Due to differences in relief, soil and climate, the Yangtze-Kiang basin is divided into three sub-divisions-
1. The Upper Course Or Szechuan Basin Or Red Basin:
Szechuan means “four streams”. The Szechuan basin is formed by the deposition of four tributaries (Min, To, Wu and Chialing- Kiang) at the source of the Yangtze-Kiang. Most of the Szechuan province in southwestern China Is included in this region.
Except for the Yangtze gorge, this lowland region is surrounded by highlands or mountains. It has been formed by the infilling of silt in an ancient lake. As the soil is red in colour this region is also called the ‘Red Basin’.
The Red Basin extends from the source of the Yangtze-Kiang to Ichang. In terms of climate, soil, terrain and natural resources, Szechuan has no rival.
It is one of the most populous of China’s provinces because of its comfortable climate, extraction of minerals, and agricultural and industrial development. The two important cities and, industrial centres are Chunking and Chengtu.
2. The Middle Course Or Central Basin Of Yangtze-Kiang:
The Middle Course or Central Basin of Yangtze-Kiang is characterized by extensive fertile plains and many lakes. It is extending from Ichang to Hunan. It includes four provinces of Hupeh, Hunan, Kiangsi and Anhwei.
It is one of the greatest agricultural regions. This region prospers in agriculture due to the presence, of
The southern provinces of Hunan and Kiangsi are famous as the huge quantity producer of paddy. Plenty of rice produced in Hunan province is known as the ‘Rice Bowl of China’ or the “Store house of rice”. Wheat, barley, sugar cane, oil seeds, cotton etc. are also produced here in notable quantities.
As the middle course or central Yangtze-Kiang basin prospers in agriculture it is known as the ‘Granéry of China’. Sericulture is an important occupation. The hill slopes have many tea gardens. The region is rich in mineral resources such as coal, iron ore, tungsten, lead, zinc, manganese and antimony.
The largest industrial conurbation in the Middle Yangtze Kiang Basin is formed by the three cities of Wuhan, Hanyang, and Hankow.
3. The Deltaic Course Or Delta Region Of Yangtze-kiang Basin:
This region extends from Nanking in the west to Shanghai in the east near the East China Sea, the mouth of the river Yangtze-kiang. The entire region lies in Kiangshu province. The delta is almost level, only 10% of it is a swamp.
It is a region with numerous canals, distributaries, lakes, dykes and sand bars, as in Holland (Netherlands) there are many Poldarlands, rivers channels, creeks and lakes. So it is called the “Holland of China” as well as the “Holland of Asia”. This delta region is also called “water country”.
Holland is lowland and gets submerged during high tides. To save the country, the people of Holland erected a number of circular dykes and thereby they have saved the country.
Just like the people of Holland, the people of the Yangtze-Kiang delta region of China also have erected a number of dykes in the delta area of the Yangtze-Kiang and thereby they have reclaimed a vast region.
It is developed in agriculture as well as agro-based industries. Because of the similarity this region is known as the “Holland of China”.
The region is developed in agriculture. Crops produced in the region are rice, wheat, cotton, tobacco, oilseeds soybeans etc. Mulberry trees are cultivated for silkworms. Animal husbandry is also developed here.
Though the region is not important in mineral wealth, yet, some coal, petroleum, salt etc. are produced the region is developed in agriculture.
Nearness to raw materials well-developed transport and communication, cheap labour, hydel and thermal power, wide market, port facilities etc. have favoured the growth of industries here.
The entire delta is developed in the cotton textile industry. Shanghai is the main cotton textile industry centre. So it is also called the “Manchester of China”.
Shanghai has always been the leading industrial centre and well as the largest city in China. Shanghai lies on the Whangpu River, 24 km from the Yangtze.
The growth of Shanghai as the premier port and city of China is due to foreign trade. It has now grown into a metropolis of 10 million people.
Except for cotton textiles, Shanghai manufactures a wide range of products including electrical appliances, bicycles, tractors and chemicals. It also has steel, ship-building and oil-refining industries.
The Yangtze-Kiang basin of China is economically developed. The causes of the economic development of this region are as follows:
The Yangtze-Kiang basin occupies nearly one-fifth of the total area of China. But at the same time, nearly one-fourth of the total population of China lives in this basin. Thus very dense population occurs in this region. The causes of this dense population are as follows:
1. Easy Earning Of Living:
Yantgtze-Kiang Delta region is densely populated because earning of living is easy here.
2. Rich In Agriculture:
The Yangtze-Kiang Basin is the richest agricultural area in China. The region is very fertile as the region is made of fertile silt deposited by the river Yangtze- Kiang. Irrigation facilities have favoured agriculture very much. Rice, wheat, tea, sugarcane, oilseeds etc are produced here.
About 70% of China’s rice is produced from this region, and 50% of other crops too. It results in more earnings from agriculture than any other region of China.
3. Rich In Mineral Resources:
The basin is also the leading mineral-producing region of China. A large amount of iron ore, petroleum, natural gas, antimony, natural gas, tungsten etc. is produced in the region which causes this region to be economically rich resulting in a dense population.
4. Industrially Developed:
The Yangtze-Kiang basin is the most industrialised region of China. Large industrial centres like Shanghai, Wuhan, Nanking, Chunking etc. are located in this basin. Therefore, the development of industries in this region has caused a great density of population.
5. Transport And Communication:
The transport and communication system of this region is well developed, because of roadways and railways facilities.
6. Others:
Amusement, education, games and other facilities are available in this basin has caused it to be the most densely populated region in China.
At present Japan is the greatest industrialised country in Asia. In the world, it ranks third only following the U.S.A. (1st) and Germany (2nd). The most important industrial region of Japan- the Kihin or Tokyo-Yokohama industrial region has developed in the Kanto plain.
Kanto – (Kwanto) plain is situated in the eastern part of Hanshu Island. Among the four main islands of Japan Hanshu is the largest one. Kanto plain is divided into seven regional divisions, which are
The density of the population of the Kanto plain region is very high. About one-third of the total population of Japan lives here. This plain extends around the gulf of Tokyo.
A number of large cities have developed along the coast of the gulf of Tokyo. Within this region, there are forty large towns including Tokyo, Yokohama, Kawasaki and Chiba.
Tokyo:
Tokyo, the capital of Japan is situated on the southeast coast of Hanshu at the head of the gulf of Tokyo. Tokyo is the largest city, important port and the largest industrial and trade centre in Japan.
It is now one of the largest cities in the world and a great centre of Japan’s political, economic and cultural life.
Over 20 million people live within a circle about 50 km from its centre. The city includes vast non-urban areas at the periphery for future growth. So Tokyo is an overbounded city. In contrast, Kolkata is an unbounded city.
Tokyo’s industrial complexes include textiles, cars, food processing, plastics, breweries, optical instruments and publishing. Tokyo is also the largest centre of printing.
Yokohama:
Yokohama is the second-largest city and the largest port in Japan. It is located about 30 km. away from Tokyo in the south of Hanshu island.
The large ships cannot enter the port of Tokyo as the gulf is shallow there. So, Yokohama plays the role of the largest external port in Japan.
Yokohama has steel, motor vehicles, chemicals, shipbuilding, oil refining and also fish canning and silk and rayon manufacturers. Its satellite town Kawasaki has ship-building, steel and textiles. Chiba is noted for its iron and steel industry.
| Industrial Region | Important Industrial Centres | Major Industries |
| Tokyo-Yokohama or Kihin Industrial Region (Kwanto Plain) | Tokyo | Cotton textiles, optical instruments, automobiles, electronic equipment, paper, printing and publishing. |
| Yokohama | Steel, motor vehicles, chemicals, shipbuilding, silk and rayon textiles. | |
| Kawasaki | Shipbuilding, steel and textiles. | |
| Chiba | Iron and steel, chemical, shipbuilding. |
The factors favourable to the growth of the Tokyo-Yokohama Industrial Belt as one of the best and most significant industrial Belt in the world are as follows:
1. Agricultural Development:
The Tokyo-Yokohama region is rich in agriculture. The volcanic fertile soil, suitable climate etc. are ideal for the production of rice and other agricultural crops which are also supplied as raw materials in a number of industries.
2. Favourable Climate:
The insular climate of this region is encouraging and suitable for hard work.
3. Density Of Population:
Being densely populated, the region is supplying a cheap and skilled labour force for industrial development.
4. The Spirit Of The Japanese People:
The spirit of the Japanese people, ‘Nippon Seichin’ has contributed largely to making Japan the industrial leader of the Orient. The Japanese are ready to work harder than almost any person on earth for the sake of their country
5. Power Resources:
Required power is obtained from a large number of hydroelectric power stations of central Hanshu and Tukai nuclear power stations.
6. Water Resources:
The short and swift-flowing rivers of Japan are helping a lot in the industrial development of this region by providing cheap hydel power and required industrial water.
7. Developed Transport And Communication System:
The region is crisscrossed by a large number of roadways and railways and there helped quick and rapid transport. The numerous natural and man-made water courses on the lowland provide excellent transport facilities.
8. Port Service:
Tokyo-Yokohama ports provide port facilities. Raw materials are imported and final goods are exported through these ports.
9. Uses Of High-Technology:
Uses of high-fi technology favoured this industrial belt to be developed in the field of industries, trade and commerce.
10. Market:
Because of the dense population, the local market and also the international market are wide.
11. Government Policy:
The policy of the Japanese Government is to ensure Japan’s survival in the face of full competition among the western industrial powers.
Important industries of Tokyo-Yokohama Industrial Región are as follows:
Though Tokyo-Yokohama industrial region is the largest industrial belt of Japan, yet at present, this region faces some problems. These are as follows:
How Can The Problems Be Solved:
The following remedies should be taken to solve the above problems of the Tokyo-Yokohama industrial region.
There are some special features of Yokohama Industrial centres in respect of other industrial regions in the world. These are as follows:
Petroleum or mineral oil is an inflammable mixture of oily hydrocarbons with very complex chemical properties. It is an important fossil fuel. Modern mechanised civilization is fueled by petroleum.
Petroleum is an important source of power, and lubrication of machines in factories and its most significant use of it is transportation.
Besides, petroleum is used to produce many substances, such as plastic, artificial rubber, artificial fibre etc. It has a wide range of uses and nowadays, it is an invaluable resource.
For its endless usefulness, petroleum is called ‘liquid gold’. Though it is such a precious resource, it is only produced in a few countries of the world.
South-West Asian countries play a very important role in world petroleum production and export. South-West Asia forms a land bridge between Europe, Asia and Africa.
The countries of South-West Asia are known as the ‘Countries of five seas’ which surround South-West Asia.
In the north of South-West Asia lies the Black Sea, in the North-West Mediterranean Sea, in the west the Red Sea, in the south Arabian Sea and in the south-east the Persian gulf.
The countries of South-West Asia are connected with other countries by water routes through one or several of the seas mentioned above and hence called “Countries of five seas”.
The countries of South-West Asia occupy the highest position in the world in respect of petroleum extraction. About 60% of the world’s total mineral oil resources are found in this region.
This region mines about 30% of the total petroleum in the world. The climate in these South-West Asian countries is very hot and dry.
The population of South- West Asia is low and the demand for petroleum is not so high. So, the best part of the oil mined is exported here and the economy of these oil-producing countries is export-oriented.
As they produce and export precious petroleum, gradually oil field-based cities have grown and they live a luxurious life.
The principal producing and exporting centres of South-west Asia are-
1. Saudi Arabia:
Saudi Arabia is the largest country in the Arabian peninsula, which is the largest peninsula in the world. At present, it ranks first in the world in petroleum production and export.
About 26% of the total petroleum reserves of the world are found in Saudi Arabia. The oil fields are located along the coast of the Persian Gulf. The on-shore (inland) fields are at Abqaik, Ghawar, Khuryas, Khursania and Al Qatif.
The off-shore fields are Abu Safa, Manifa, Marjan and Safaniya. The largest on-shore oil field in Saudi Arabia, as well as Asia and the World, is Ghawar and the largest off-shore oil field is Safaniya. Dhahran and Rus Tanura (the largest oil refinery in Saudi Arabia) are noted for oil refineries.
2. Iraq :
Iraq lies mainly in the lower basin of the Tigris-Euphrates river. Petroleum is easily the most important commodity of Iraq.
Iraq is the fourth largest oil producer in the Middle East. The Kirkuk is the largest oil-producing region. Other oil fields of significance are Mosul, Basra, Warfa- Bargon, Zubain, Rumalia etc.
3. Iran :
Iran lies east of Saudi Arabia and on the other side Gulf of Persia. Petroleum is the most important resource of Iran. In mineral oil production Iran occupies the fourth position in the world and holds the second position among the countries of the Middle East.
The major oil fields are located on the coastal strip of the Persian Gulf and on the foothills of Zagros Mountain. Much oil, nearly half of the total production comes from Aghajari.
Other important oil fields found in this area are-Gachsaran, Lali, Masjid-i-Suleiman, Halftkel, Marun, Naft-i-Shah, Awaj etc. Abadan is one of the greatest oil-refining centres in the world. One-third of the crude oil is refined in Iran.
4. Kuwait :
Kuwait, a small country, on the northeast of the Persian Gulf, is noted for petroleum. The per capita income of the local people is the highest in the world because the per capita production of petroleum is the highest.
Burgan and near it Magwa-Ahmadi produce the maximum oil. More than 80% of the production is piped to Mina-al-Ahmadi port for export.
5. United Arab Emirates (UAE):
U. A. E. is located to the east of Saudi Arabia, adjacent to the Persian Gulf. It is formed of seven Arab Emirates:
6. Bahrain :
In the Middle East Belt, Petroleum was first struck in Bahrain in 1932. Jabal Al-Dukhan is the major oilfield. The oil fields of Awali is also significant.
7. Qatar:
Qatar is a small country located in the east of Saudi Arabia on the coastal margin of the Persian Gulf. Jebel-Dukhan and Id-Al-Sharkhi are important for oil mines.
8. Oman:
Oman, situated on the southeast of the Arabian peninsula, is also noted for petroleum: Fahud and Natih are the major oilfields of the country.
9. Syria:
Syria is nearly self-sufficient in petroleum production and is exporting a little.
| Petroleum Producing and Exporting Countries Of South-West Asia | Capital Of the Countries | Important Oil-Fields |
| 1. Saudi Arabia | Riyadh | Ghawar, Abqaik, Dhahran, Khuryas, Khursania, Safaniya Manifa. |
| 2. Iraq | Baghdad | Kirkuk, Mosul, Basra, Warfa-Bargon, Zubafn, Rumalia etc. |
| 3. Iran | Tehran | Masjid-i-Suleiman, Naft-i-shah, Lali, Aghajari, Halftkel, Gach saran. etc. |
| 4. Kuwait | Al-Kuwait/ Kuwait City | Burga/i, Magwa-Ahmadi, Aaljara. |
| 5. United Arab Emirates | Abu Dhabi | Dubai, Abu Dhabi, Murban, Amirshahi. |
| 6. Bahrain | Manama | Jabal-al-Dukhan, Awali. |
| 7. Qatar | Doha | Jebel Dukhan, Id-el-ljba, Id-al-Sharkhi. |
| 8. Oman | Muscat | Fahud and Natih |
| 9. Syria | Damascus | Al-ljba, Omar. |
OPEC:
Most of South-West Asia and a few other petroleum-producing and exporting countries have formed an organization in 1960 to protect their oil resources, and improve their interest and their benefits. T
The organization of the most oil-producing centres of the world is called OPEC or the Organization of Petroleum Exporting Countries. In Asia, these countries include Saudi Arabia, Iraq, Iran, Kuwait, U. A. E, Qatar and Indonesia.
In Africa, they include Gabon, Nigeria, Libya and Algeria. In South America, they include Ecuador and Venezuela. The main objectives of the OPEC are
The OPEC countries export nearly 80% of the petroleum produced in the world and they have nearly two-thirds of the petroleum reserves of the world.
What Is Pollution: The fouling of the environment by man, which makes it harmful for living organisms or reduces its amenity value is called pollution.
Pollution changes the physical, chemical or biological balance of the environment that has adverse effects on the normal functioning of all life forms, including humans.
Different Types Of Pollution: Pollution may be divided into two major categories :
Physical pollution may be air pollution, water pollution, soil or land pollution, etc. Social pollution may be defined as a kind of pollution by which the quality of the social environment deteriorates. Population explosion, sociological pollution, economic pollution etc.
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On the basis of area and source pollution may be categorised into-
What Is Water Pollution: According to the President’s Science Advisory Committee, Washington (1965), water pollution is, “Alteration in physical, chemical and biological characteristics of water which may cause harmful effects on human and aquatic life.”
” class 7 sst geography chapter 5″
According to the definition of the World Health Organisation (1966), water pollution occurs when foreign materials either from natural or other sources are contaminated with water supplies and may be harmful to life because of their toxicity, reduction of normal oxygen level of water, aesthetically unsuitable effects and spread of epidemic diseases.
When Water Is Polluted: When different unsuitable organic matters, germs and force chemicals make water unsuitable for human beings and other members of the biotic world and also make it unhabitable for aquatic life, it is said to be polluted.
Different Types Of Water Pollution: There are mainly five types of water pollution. These are as follows:
Point Source: These direct sources of water Pollution may be controlled by the making of laws. These are-
Non-Point Source: These indirect sources of water pollution cannot be identified easily. So these are not controlled by the laws Example., Agricultural land, Forests, Dirty water of roads etc.
Pollutants: Something that pollutes the environment is called a pollutant. Pollutants are substances which cause pollution. Pollutants may be solid, liquid or gaseous substances.
Water Pollutants: Something that pollutes and deteriorates the quality of water is called water pollutants. These pollutants may be natural or anthropogenic.
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Types Of Water Pollutants :
Water pollutants may also be divided into
1. Natural Causes :
2. Anthropogenic Causes :
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In the following table, the important causes/sources of water pollution are mentioned and indicate how water gets polluted.
The diseases such as Diarrhoea, Cholera, Dysentery, Typhoid, Polio, Jaundice etc. are caused by polluted and contaminated water.
Causes Of A Few Diseases Which Are Created By Water Pollution.
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| Name of the Diseases | Causes | Problems |
| 1. Arsenicosis | 1. Due to the heavy amount of arsenic in underground water | 1. Weakness, rough skin, cramps In muscle. |
| 2. Black foot disease. | 2. Due to the heavy amount of arsenic in underground water. | 2. Besides skin disease, anaemia, and liver and lung cancer can attack. |
| 3. Flourosh | 3. Fluoride pollution. | 3. Problem with teeth, bones etc |
| 4. Minamata disease | 4. Mercury pollution. Problems. | 4. Loss of eye-sight, loss of sense of brain. |
| 5. ItaMtai | 5. Due to cadmium pollution. | 5. High blood pressure, and kidney damage. |
| 6. Dyslexia | 6. Due to an excessive amount of lead | 6. Decrease of haemoglobin, weakness of muscle vomiting tendency. |
In 1932, along the coast of Minamata Bay in Japan liquid waste of mercury was thrown. Due to this dreadful mercury pollution in water, Innumerable people and animals died for about three decades.
In 1991, at the time of the Gulf war, many oil wells were ignited in Kuwait by Iraq. A large quantity of mineral oil polluted the water of the Persian Gulf causing the death of countless marine creatures.
Due to the excessive amount of arsenic in underground water of the districts of Malda, Nadia, Burdwan, Hooghly, Howrah, North and South 24 Parganas of west Bengal black wounds are formed and this is called ‘Black foot’ disease.
Due to the water pollution of the Haldi river after the formation of the petrochemical industry at Haldia, the frequent visit of Hilsa fish at the mouth of the Haldi river has decreased.
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Due to Eutrophication fish and other aquatic animals die as the percentage of oxygen in water decreases. The pisciculture at the fisheries of the wetlands of East Kolkata has decreased due to the use of pesticides.
For this reason, a large quantity of fish has died at Kuttuner of Kerala, Kolleru of Andhra Pradesh and Chilka of Odisha.
Water Is Life: Man cannot live without drinking water, perhaps that’s why water, in other words, is called ‘life’. The supply of water for bathing, cooking, drinking, irrigation and industrial purposes is very essential and important.
Crisis Of Fresh Water: Fresh water is the most important natural resource. Though about 71% of the earth’s surface is covered with water bodies, still demand for freshwater remains the main problem for people all over the world.
97% of the water on earth is the saline sea or ocean water out of the remaining 3%, 2% is trapped in ice caps. Only 1% remains in the rivers, lakes underground aquifers and other freshwater bodies.
States Suffering From Acute Water Crisis: Due to overuse and pollution of water severe crisis of fresh water has affected some parts of the world such as some parts of the states of Africa, Australia, West Asia and South America.
Our country India is a land of rivers but presently highly polluted water from the rivers like the Ganges, Krishna, Kaveri, Godavari and Yamuna is not usable as drinking water.
Purifying Water: Recently, even though there is the availability of drinking water for most people in India, the only source of drinking water in remote areas is the river and ponds.
These are full of water but that water is dirty, polluted and not suitable for using as well as drinking. So purifying water is very essential. There are some easy methods by which the purification of water is possible.
Strict controls are needed to prevent water pollution. These are as follows:
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What Can Be Done By The Student Of Class Seven?
What Is Soil?
Soil is a fundamental natural resource. The loose inorganic and organic unconsolidated material which forms the uppermost layer of the earth’s crust is called soil. It consists of many minerals and organic particles, humus, bacteria, etc.
Soil is formed through the chemical and mechanical weathering of rock cover.
Soil Is The Host Of Life: ‘Soil is a valuable gift of nature. It is one of the most useful renewable resources. About one-third (30%) of the earth is landmass and soil covers, the upper level of it.
Mankind has lived and continues to live on the soil. Many human and economic activities depend upon soils.
All our food comes directly or indirectly from the soil. Livestock farming depends upon the raising of grass on different soils.
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Soils form an important element for all living things. Soils have affected the march of civilizations. Ancient civilizations developed in fertile river valleys. Fertile soils attract human settlements.
The density of the population depends upon soil fertility and productivity. So it is called that “soil is the host of life”.
soil pollution
What Is Soil Pollution: A decrease in the quality or fertility of soil either due to anthropogenic sources or natural sources or both is called soil pollution.
When Soil Is Polluted?
Soil is polluted when it loses its quality or fertility because of the use of dangerous chemicals such as pesticides and fertilizers and the dumping of industrial wastes, garbage, plastic, and radioactive materials.
Soil Pollutants: The soil pollutants may be so chemical and organic or biological types. Some of the pollutants have been reported to be naturally present in harmful concentrations.
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Naturally, present organic pollutants are solanine, gossypol, oxalic acid, and erucic acid. The potential chemical pollutants are fluoride, nitrate, pesticides, radioactive isotopes, and many trace elements, e.g. selenium, lead, mercury, chromium, tin, cadmium, etc.
Depletion of valuable land resources or soil is a serious problem almost in every corner of the world. There are numerous sources of soil pollution, but the most important among them are the following three.
In developing countries like India, the major source of soil pollution is, of this type and is prevalent in both urban as well as rural regions.
In the following table, the important causes/sources of soil pollution are mentioned and indicate how soil gets polluted.
Chapter 8 Soil Pollution A few specific incidents of soil pollution
In 1984 at midnight, poisonous gas from the Union Carbide factory in Bhopal (Capital of M.P.), India mixed with air and soil. Many people died and since then many were disabled.
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In 1986 an accident occurred in Chornobyl nuclear reactor in Ukraine and in 2011 an accident occurred in Fukushima Daichi nuclear reactor in Japan. Disastrous radio-active wastes spread on soil, water, and air in surrounding areas, and many people were affected.
“effects of soil pollution on human health “
Effects Of Soil Pollution: Effects of soil pollution on human beings, animals, and plants are far-reaching. Since pollutants degrade the quality of the soil. This results in a substantial decrease in agricultural production.
Chemical pollutants in form of chemical fertilizers, pesticides, and insecticides after reaching the soil eventually reach the human and animal bodies through food chains and cause various diseases and several deaths.
Much environmental damage has been done in the past – through ignorance or carelessness, and there are now increasingly strict controls to try to prevent further damage.
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In These Ways, We Can Control Soil/Land Pollution.
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What To Do:
What Not To Do:
In geography, any natural solid material which forms the crust of the Earth is called a rock. A rock is simply an aggregate of various minerals but in the scientific sense, rocks are the materials that make up the earth’s crust.
A rock has no definite chemical composition as minerals. The hardness, color, shape, and rigidity of rocks depend upon their minerals.
Different Types Of Rocks: On The Basis Of Their Mode Of Formation, Rocks Are Classified Into Three Types:
1. Igneous Rocks: Igneous rocks are those rocks that have been formed by cooling. and solidification of lav The word ‘Igneous’ is derived from the Latin word ‘Ignis’ meaning ‘fire’. In the beginning, when the Earth was born, it was just a glowing ball of gas.
Gradually it cooled down and its molten volatile surface solidified.
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In this way, the igneous rocks formed at the first on the earth’s crust. Hence it is called ‘Primary Rock’. It has no layer and that is characteristics of igneous rocks why it is called ‘Unstratified rock’.
study of rocks and soil
Characteristics :
Examples: Granite, Basalt, Dolerite, and Gabro et are examples of igneous rocks. Granite is used for house building and idol-making. Basalt, Dolerite is quarried for road-making.
2. Sedimentary Rocks: A rock composed of sediments and generally having a layered (Stratified) appearance is called ‘sedimentary rock’.
Sedimentary rocks are formed from the sediment accumulated over a long period, usually underwater at the bottom of the sea, ocean, and lakes in layers. Layers are known as strat So, these rocks are also called ‘Stratified Rocks’.
Characteristics :
Examples: Sandstone, Mudstone, Limestone, Dolomite, Gypsum, and Rock salt et are. important sedimentary rocks. Sandstones and Mudstones are used as house-building materials. Limestone is used as raw materials in cement, chemical and iron, and steel industries.
3. Metamorphic Rocks : Metamorphic rocks are those rocks that have been changed in their form, and color et due to intense heat, tremendous pressure, and chemical action.
Characteristics:
Example: Examples of metamorphic rocks include-Granites changes into gneiss, Basalt changes into Amphibolite, Limestone changes into Marble, Sandstone changes into Quartzite and Coal changes into Graphite.
Marble is extensively used by architects. The famous Taj Mahal is made of marble. Slates are used in making blackboards and can be used as a substance for writing.
Soils are the top covering of the earth’s surface and have been formed by the wear and tear of rocks and also vegetable and animal matter. The change from hard and rugged rocks to soft, fine-grained soil takes a long time.
The first step in this direction is the disintegration or weathering of rocks.
Weathering contributes much to the formation of soil. Mechanical or physical and chemical weathering plays a very important part in the development of soils, so essential to sustaining every form of life on the earth.
The soil formation process is an extremely slow one. For instance, the development of a soil layer of 2.5 cm may have taken well over a thousand years.
The disintegration of rock by weathering often produces a layer of loose rock materials.
It remains overlying on the bed-rocks, i.e. the primary rock bed of the region. This covering of loose materials over the primary rock bed is known as ‘regolith’. Soil is derived from regolith by different natural processes.
Biological weathering by plants and animals often plays an important role in information soil. Bacteria, fungi, and protozoa cause the decay of plants and animals.
Burrowing animals also help in it. When all these die and decay, minerals and humus are added to the upper layer of soil (The organic matter in the soil which differentiates from regolith and which comes from animal and vegetable decay, is called humus).
The formation of soil can be understood from the chart given below.
While the chemical action produces the elements so essential for plant growth, it is the mechanical action or the impact of physical forces that gives structure and texture to the soil.
Though soils are derived from rocks there are some differences between rocks and soils. These are as follows:
| Rocks | Soils |
| 1. Any natural solid material which forms the crust of the Earth is called a rock. | 1. The uppermost layer of the Earth’s crust covering loose materials is called soil. |
| 2. Rocks are aggregates of minerals. | 2. Rock particles make soil. |
| 3. Rocks are formed by cooling and solidification of lava sedimentation of silts and metamorphism. | 3. It forms slowly over a long period by the mechanical and chemical weathering of bedrock. |
| 4. Rocks do not have definite layers. | 4. The soil has definite layers. |
| 5. The rock consists of different types of minerals. | 5. The soil consists of mineral particles, organic matter (humus), water, air, and living organisms (bacteria). |
| 6. Rocks have a greater depth. | 6. Soils are found up to a depth of 2-3 m. |
| 7. Rocks are harder than soils. | 7. Soils are softer than rocks. |
| 8. Specific gravity of rock is higher than soil. | 8. Specific gravity of soil is lower than a rock. |
What Is Soil Made Of :
In the non-living part of the soil, rock waste is produced by weathering and erosion. Its particles are usually composed of gravel, silt, and clay. The living part of the soil contains the roots of the plants, fungi, bacteria, insects, small biting animals et
Living and non-living colloids play an important chemical role in the development of soils.
The main factors in the formation of soils are
1. Parent rocks: Parent materials over which the rock waste and soil develop are the most important factor. The texture and structure of soils depend on the parent rock.
2. Relief: Ordinary slopes where water drainage is good to have the ideal condition for the development of soil. Steep slopes have thin soil layers, whereas the valleys and lowlands possess thick fertile soils.
3. Climate: Climate is considered to be the most important factor in the development of soil. The most important elements of climate are-
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1. Water or Humidity: Water or humidity is the most important element for the chemical and biological processes of soil development.
2. Temperature: When the temperature is high, chemical and biological activities are accelerated.
3. Air/wind: The role of air/wind is not very important. Air/wind increases evaporation from the soil. The winds erode the upper layers of the soil and transport them to distinct places.
4. Organic Matters (Plants And Animals): The action of animals and plants over the soil is very important. Vegetation is of two types-
5. Time: The soil formation process is an extremely slow one. It does not form in a day. For instance, the development of a soil layer of 2.5 cm may be taken well over a thousand years. Soils in wet areas require less time to develop than in dry areas.
Soil texture refers to the size of its grains or particles. On the basis of texture, the soil can be divided into the following types.
1. Sand Or Sandy Soil: The rock particles ranging in diameter from 0.02 to 2.00 mm make sand. The sandy soil is dominated by sand. It contains about 80% of sand particles and 20% of clay or silt. Sandstone is a rock, composed of sand grains. Sandy soil has bigger grains and bigger spaces between grains. It absorbs water in no time. It is not suited for agriculture.
2. Clay Or Clayey Soil: The soil composed of the finest rock particles is called clay the size of rock particles is about 0-002 mm the soil contains about 28% of clay and the rest particles or another size. The grains and pore spaces are very small. Water logging is common in such soils. They are better suited to agriculture than sandy soil.
3. Loam/ Loamy Soil: Loamy soils are a mixture of both sand and clay. It contains equal portions of sand and clay. Depending upon a preponderance of the two, they are called either sandy loams or clayey loams. This soil is very well aerated and watered. So, this type of soil is the best suited for cultivation.
| Soil Types | Silt contains |
| Clay | 0.45 |
| Clay loam | 0.42 |
| Loam | 0.42 |
| Silt | 0.82 |
| Sandy loam | 0.14 |
| Sand | 0.12 |
| Clay contains | Sand contains |
| 0.45 | 0.1 |
| 0.25 | 0.33 |
| 0.18 | 0.4 |
| 0.13 | 0.05 |
| 0.11 | 0.75 |
| 0.08 | 0.8 |
“rocks and soils “
Different Characters Of Different Soils :
| Types of Soil | Grain size | Capacity to retain wates | Crops |
| Clayey | Plate-shaped grains are found in compact and fine grains | Water cannot move rapidly through it | Rice, Watermelon. |
| Loamy | The grain size of the soil is smaller than sandy soil and bigger than clay because it is a mixture of clay and soil. | It is well watered. | The best soil for plant growth as well as agricultural crops. Sugar-cane, pulses, wheat, rice, oil seeds, etc. |
| Sandy | Sand grains are rounded or irregular in shape. They are bigger grains than loams and clay. 1-0-005 | It does not hold water well and has large pore spaces between the grains water drains off rapidly. | Wheat, oil seeds, melon, etc. |
Rivers are the most distinctive geographical features on the earth’s surface. They are the most important sculpturing agents of landforms.
Definition Of River: Rivers are channels of running water. A river is a natural stream of running water which flows in a channel along the slope of the land towards a low land which may be an ocean, sea, lake, depression, another stream of water or large water body.
Source Of River : A river begins its flow from a spring, lake or from the melting water of a glacier on a high mountain, or from a rainy place on uplands and plateaus. The place from where a river begins its flow is called the source of a river.
Mouth Of The River: The place where its flow ends, is called the mouth or confluence of a river. The mouth or confluence of the Ganga is in the Bay of Bengal near Sagar Island.
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Catchment Area: The area from which a single river system collects its waters is called its catchment area. Rainwater and ice-melt water drain through several small channels in high. mountainous regions.
These channels generally converse at the foothills to form rivers.
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River Valley: The valley is confined by lateral banks through which the river flows.
River Basin: The region through which a river, its tributaries and distributaries are flowing is called the River basin.
River-Divide/Water Divide: A high land. (Moutain or plateau) that separates one river basin from another is called a water divide Example. Vindhya Range is a water divide between the northern and southern rivers of India. The tract of land between two adjacent river valleys is called Interfluve or a Doab.
Example. Ganga-Yamuna Doab between the river Ganga and Yamuna.
River System: A river together with all its tributaries and distributaries make up a river system.
Tributaries: A small stream or river that descends to join the larger main stream or river is called a tributary. For e.g. Yamuna is the largest or main tributary of the river Ganga.
Distributaries: On its lower course, particularly near the mouth, several branches come out from the main river and they are known as distributaries, for Example. Padma and Bhagirathi of river Ganga.
| Tributary | Distributary |
| 1. A tributary is a river joining the main river. | 1. A distributary is a river draining out of a main river. |
| 2. It increases the volume of water in the main river. | 2. It decreases the volume of water in the main river. |
| 3. It joins the main river in its middle course and lower course and helps in the formation of the flood plain. | 3. It drains out the main river in its lower course and helps in the formation of the delta. |
| 4. River Yamuna is a tributary of the Ganga. | 4. River Ganga has two important distributaries, Example. Bhagirathi in W. Bengal and Padma |
The path of a river from its source to its mouth is known as its course. From the source to the mouth of a river, there are variations in the shape, size and depth of the valley. Based on these variations Padma river course is divided into three parts
The river which presents these three courses distinctly is called Ideal River. The Ganga is an example of an ideal river.
Inland River: As the river drains within the country it forms an inland river. A river which has no outlet and so does not reach the sea and empties itself into an inland lake or swamp is called an Inland or Internal or Interior River.
Luni in India is an example of an inland river. Tarim is the longest inland river in the world.
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International River: When a river flows through many countries it is called an International River. Indus, Ganges, and Brahmaputra in Asia, the Rhine, and the Danube in Europe are some examples.
Perennial River: A perennial river has water all the time. When a river has its source high up in the mountainous area is generally fed by ice-melt water and it does not dry up during any time of the year. It is called the Perennial River. The Ganges is an example of a perennial river.
Non-Perennial River: Non-perennial or temporary river tastes life only during the wet season. When a river has its source in a lower plateau or hilly region it is fed by rainwater and it is filled with water during the rainy season during other parts of the year it tends to dry up.
It is called the non-perennial river. River Damodar is a non-perennial river.
A river performs three main types of work:
Erosion: When a river flows swiftly, it mainly wears away and breaks down its bed and sides. This is erosion. The erosional work of the river depends upon the following factors:
Transportation: All along the course, the river carries the eroded materials from one place to another is called transportation.
The Transporting Power Of A River Depends Upon :
Deposition: The work in which the river deposits the transported material is called deposition. Deposition results when
Energy is the ability to do work and the amount of energy which a river has determines whether it can effectively erode its valley and transport the material it is carrying, or whether it drops the material in the form of a deposition.
The amount of erosion that a river can achieve depends on its energy.
Energy is also needed to transport the pebbles, sand, silt etc. The deposition of materials starts when their energy or power is reduced.
The Energy Or Power Of A River Depends Upon The Following Factors:
How Similar Is A River To A Human Life:
A river while flowing can be said to be like a human being. Its life cycle consists of similar three stages-youth, maturity and old age. A river may be young at its source, mature in the middle course and old near its mouth.
Youthful Stage: In its upper course a river is considered ‘youthful’ because it is young in behaves just like an energetic, restless playful boy. In this stage, it flows rapidly. A young river is most often a very powerful agent of denudation.
Mature Stage: In the middle course a river reaches lower lands. The slope is gradually reduced, so the energy and the speed of the river are reduced. Then the river behaves like a mature person, just as calm and gentle.
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Old Stage: When a river comes close to its mouth, near the sea or the water body into which it is going to empty itself it is called the lower course of a river. Like an old man, in its lower or ‘old’ course a river cannot move fast or straight.
To remain immortal it seeks new ways or distributaries to distribute its tribute of rich silty water.
The upper course of a river lies in the mountains. Here river water flows very swiftly as it comes down the steep slopes. Erosion and corrosion are both characteristic features of the upper course of the river.
Landforms: The great velocity in the river has many features we see in the land as a result of the forceful down-cutting activity of the river. They are as follows:
Valleys of Different Shapes and Sizes: The valleys which a river in its upper course carves out include V-shaped valleys, gorges, l-shaped valleys and canyons.
1. V-shaped valley: A V-shaped valley is one in which the river flows at the bottom of the valley which is narrow but opens out wider and wider upwards. Such a valley reminds us of the English letter ‘V’. This is why these are called V-shaped valleys.
2. Gorge: Very deep and narrow river valley with vertical sides is called a Gorge. A gorge does not have much longer. Both the Indus and the Brahmaputra have carved out deep gorges in the Himalayas. The gorge of the Colca in south-east Peru is the world’s deepest gorge (4375 m)
3. Canyon: In arid or semi-arid areas of the desert little rainfall and rapid down-cutting create longer and deeper very narrow
‘I’ shaped valleys called canyons. The 446 km. long and around 1600 metres deep ‘The Grand Canyon’ of the Colorado river in the U.S.A. is the largest canyon in the world.
Distinguish Between Gorges And Canyons :
| Gorges | Canyons |
| 1. Gourges are deep and narrow and resemble a narrow V-shaped valley. | 1. Canyons are very, deep and extremely narrow, so, they resemble the English alphabet Y. |
| 2. Gorges are formed due to high velocity and rainy mountain areas. | 2. Canyons are formed in arid or semi-arid regions. |
| 3. In gorges vertical erosion is greater than lateral erosion/ as rainfall is high, either river bank gets eroded. |
3. In canyons lateral erosion is nearly nil, and vertical |
4. Water Falls: When a river waterfalls suddenly from a certain height, along a vertical slope, it is known as a waterfall. Waterfalls are formed in various ways. Some of them are mentioned below:
5. Plunge Pool: The valley floor breaks where the waterfalls and a pool are created at the foot of a waterfall by plunging water. It is called a plunge pool.
6. Rapids Cascades and Cataracts: When the river flows along the unequal slopes of resistant rocks rapids, cascades and cataracts are formed. These are commonly found in a mountainous regions.
7. Potholes: A round hole worn in the rock of river beds by the swirling action of gravel and stones is called Pothole. These features are common on the mountain course of the Himalayan rivers.
8. Interlocking Spur: A series of projections from both sides of a river valley which when viewed from above appeared to interlock with each other. This is called Interlocking Spur.
The middle course of a river begins when it leaves the mountain and enters of lowland. At this stage, the volume of water increases as some more tributaries join the river. The ‘river widens its valley.
The river is said to be mature. As the slope of the land becomes gentler in the middle course, the speed and energy of the river are reduced. The main work of the river is transportation. (Though the river also deposits some amount of the materials).
Landforms: The remarkable landforms of this stage are the following:
1. Wide River Valley: As the energy decreases in the middle course of the river due to less velocity, lateral erosion of the river increase while vertical erosion decreases. This widens the river valley and the depth decreases.
2. Alluvial Fan: A fan-shaped landform composed of alluvium deposition in the foothills where a constricted river enters a main valley or emerges from mountains onto a plain. It is called an alluvial fan or an alluvial cone.
3. Meander: A pronounced curve or loop in the middle course of a river channel is known as a meander. It is so named. after the ‘Meanderez’ river of Turkey which has a serpentine or zig-zag or meandering course. The Ganga near Varanasi shows a prominent meandering.
4. Ox-Bow Or Horse-Shoe Lake: In the meandering course, often the river cuts through the two bends of a meander or curve, to flow straight.
The bend or behind the river, this isolated or abandoned part of the river turns into shaped as an oxbow or horseshoe.
So this lake is called Ox-bow or Horseshoe Lake. It is seen in the flood plains of Ganga, near Patna of Bihar.
5. Sand Bank, Sand-Bar or River Island: The reduced velocity in the river in the middle course reduces the load transporting capacity of the river. Thus the river deposits a part of the load on its bank and bed.
The large deposits of sand, stones, and pebbles on the river bank are known as sand-bank and the deposits of sand, stones, and pebbles on the river bed are called sand-bars or river islands.
There are many sand banks and sand bars in the course of river Ganga in Bihar and west Bengal and the course of river Brahmaputra in Assam.
6. Flood-Plain and Natural Levee: In the rainy season when extra water is added, the river floods its surrounding areas. By repeated floods sands, and silts deposited on both the banks of a river gradually build up plain.
It is called Flood-Plain.A bank of alluvium bordering a river that is built up by deposition and lies above the level of the flood plain.
As this embankment is formed naturally, so it is called Natural Levee. Natural levees are found along the course of the great rivers such as the Ganga, Howang-Ho and Yangtze.
When a river arrives at its mouth near the sea or any large water body slope of the land becomes very much less or gentle, so the velocity is very low.
This part of the river is called Lower or Delta course. From Rajmahal hill in Jharkhand to the mouth of the Ganga at the Bay of Bengal is the Lower or Delta course of the river Ganga.
Landforms: The very low velocity of the river, the principal work of a river is deposition. The major features produced in this course of the river are:
1. Very wide (Broad) And Shallow River valley: As the river velocity is low, down-cutting is reduced but side-cutting is increased. So the depth of the river decreases and the valley widens a lot.
2. Sand Bank, Sand Bar, Flood-Plain, Natural Levee And Horse-Shoe Or Ox-Bow Lake: Like the middle or plain course of a river sand bar, sandbank, flood-plain, natural levee and ox-bow or horse-shoe lakes are also formed in the lower course and these are more in numbers.
3. Delta: On entering the sea a river deposits all the load at the mouth to form an alluvial triangular island which looks like the Greek letter Slip-off-slope A (delta). So, this island is called ‘Delta’. The Ganga- Brahmaputra delta is the largest delta in the world.
Types Of Beltas: Three types of delta are usually distinguished:
4. Estuary: When a river enters the sea through a deep funnel-shaped tidal mouth where fresh and saline water is mixed. This wide mouth of the river is called Estuary. The estuary of Ob river is the widest estuary in the world.
| Delta | Estuary |
| 1. A delta is a triangular-shaped alluvial land formed at the mouth of a river. | 1. An estuary is a funnel-shaped channel formed at the mouth of a river. |
| 2. It is formed by deposition when there is the absence of high velocity of tides and currents. | 2. It is formed when deposition does not take place due to strong tides and currents. Lateral erosion also increases here. |
| 3. Ganges-Brahmaputra form a large delta but Narmada-Tapti do not form deltas. | 3. River Ganges, Matla, Ob, Amazon etc. have estuaries at their mouths. |
The rivers are closely related to our lives. The relationship constantly changing as men themselves have changed. The importance of the rivers may be summed up as follows:
Why are not all places on the earth’s surface similar?
The surface of the earth which is made of various types of rocks is neither stable nor permanent in its form. Somewhere it is higher, or in others, it is flat and even slopes.
Being subject to pressure, movement, forces of tension and compression and fracture, the form of the earth’s surface continuously changes.
There are two types of forces working on the earth’s surface-
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1. Endogenetic forces have their origin deep down in the earth’s interior and work from below. They can be said to be two types-
Slow forces which bring about subsidence and elevation, cause folds and faults in the crust of the earth and is known as mountain-building activity. These activities are carried on slowly and are called Diastrophism.
The sudden forces include within their scope the earthquake and volcanic eruptions.
2. Exogenetic forces are connected with the atmosphere and consequently are external to the earth. Rain, snow and sun on one hand and running water (river), wind and moving ice on the other, are always busy levelling down the irregularities of the earth’s crust.
Out of the continuous action and reaction of these two types of forces- one trying to raise from within the interior and the other trying to level down the raised surfaces-are born the various form seen on the earth’s crust.
These are called landforms and they exercise a very powerful influence on the life and activities of man on this planet on which we live.
The term ‘landform’ is applied by physiographers to each of the multitudinous features that taken together make up the surface of the earth. Any feature of the earth’s surface that possesses. a particular shape and form are called a ‘landform’.
It describes the shape, size and Mountai structure of the land.
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In fact, a landform is a natural phenomenon of a land area.on the earth’s surface. There are many forms of land on the surface of the erotic earth. Continents, oceans, mountains, plateaus, valleys; deltas etc.
These are some the examples of landforms. Height, slope, and relief are the chief elements giving diversity to landforms.
Landforms Must Have The Following Characteristics
Landforms can be divided into three orders. First-order landforms are continents and oceans. Mountains, 1000 m Plateaus and Plains are among the second-order landforms. The third-order landforms include mountain Sea sections, hills, valleys, deltas etc.
There are three major landforms on the earth basis of height, slope, structure, ruggedness and irregularities.
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These are-
A mountain is a very high, rocky, steep-sided, uneven rugged landmass with a narrow peak or summit.
Characteristics Of Mountains And Hills :
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Tops of the mountains have conical peaks. The sharp or narrow pointed top of a mountain is called it summit or peak. A single more or less isolated summit is called a ‘Peak’.
A Mountain Have Several Forms Viz.
Many mountain ranges spread out in different directions converging or meeting in a highland which is called a Mountain knot. Example-The Pamir plateau of Asia.
Hills: Hills are natural lower highlands of the earth’s surface, not so high as mountains (Considerably ranging between 300 m to 1000 m) and stretching over a less extensive area with less steeply inclined sides. eg. Rajmahal Hills of Jharkhand, Ayodhya, Susunia, Biharinath etc. of West Bengal are examples of hills.
Types Of Mountains: There are different types of mountains, Based on their mode of formation four main types of mountains can be distinguished-
Folded mountains are formed due to the folding of crustal rocks by the compressive force generated by endogenetic forces coming from within the earth.
Characteristics Of Folded Mountains :
Folded Mountains are of two types-
1. Young Fold Mountains:
have been formed during the most recent mountain-building periods. The Himalayas, the Alps, the Rockies and the Andes are prominent examples.
Old fold mountains have formed during earlier mountain-building periods, like the Urals, the Appalachians etc. The Aravallis are considered to be the oldest folded mountain.
2. Block Mountains:
An upland mass created by the uplift of land through earth movements between faults or by the sinking of the land outside the faults is called a block mountain.
Characteristics :
Examples are Black Forest mountain in Germany, Vosges mountain in France, and Vindhyas and Satpuras in India.
When magma or lava gushing out from the interior of the earth spread and solidifies, a mountain is formed by the accumulation of lava: This type of mountain is called a volcano/a volcanic mountain or mountains of accumulation.
Mt. Fuji in Japan, Barren of Andaman island in India, Vesuvius in Italy, and Krakatau in Indonesia are some examples.
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Volcano Characteristics :
When an original highland (mountain/plateau) is eroded for a long time, its soft rocks are removed and the hard rocks stand out as mountains. These are called Residual or Relict mountains.
Nilgiris of Southern and Aravalli of North-Western India are examples of this type.
Relict Mountain Characteristics :
A plateau is an extensive upland that has an almost flat undulating topped surface with steep sides.
Plateau Characteristics :
Formation Of Plateaus:
Plateaus are formed in the following ways-
The plateaus which have mountain rims around their surroundings are known as Intermontane plateaus. The upliftment of fold mountains often builds up the intermontane plateaus in between their ranges.
The Tibetan Plateau in between the Himalayas and the Kunlun is an example of this plateau which is the largest and most extensive plateau in the world.
The Pamir in Asia is the highest plateau (4873 m.) in the world and that is why it is called the ‘Roof of the world’. The Ladakh Plateau (3500 m) of Kashmir is the highest plateau in India.
Lava Plateau: The Plateaus which are formed by volcanic lava, are called lava plateaus. These plateaus are formed as a result of the lava flow in volcanic regions.
The plateau of Maharashtra, situated in the northwest of the Deccan Plateau in India is an example of this type of plateau.
Dissected Plateaus:
Sometimes, the softer parts of a plateau or highland are worn away by water, glacier, and wind but the harder parts remain as before. The plateau is then divided into a number of uplands and valleys.
It is called a dissected plateau. The Chhotonagpur plateau of Jharkhand in India presents a classic example of the dissected plateau.
An extensive area of flat or near leveled or gently undulating land, usually lowland is called a plain. Plains are formed by the internal earth movements and the external agents of nature, such as the sun, rain, running water, and the glacier.
The plains are formed in the following ways:
The plains which are formed by the deposition of alluvium are called alluvial plains. The Indo-Ganga-Brahmaputra plain of North India is an example of an alluvial plain.
Lava which is extruded by fissure eruption accumulates over vast, flat low-lying stretches from a plain. It is known as a Lava plain. This plan is found on the margin of the Lava plateaus of the Deccan in India.
A plain may be formed by the deposition of fine sand and silts blown by the wind. This is called Loess plain. The largest loess plain of the world is found in the Hwang Ho basin of Northern China.
Landforms exert a significant influence on the life and activity of man. Different types of landform influence differently and for this, we see different types of modes of life on the different parts of the earth. Mountain, plateaus, and plains exert their influence differently.
Influence Of Mountain On Human Lives And Activities :
The Following Are The Influence Of Mountain On the Life And Activity Of Man :
Influence Of Plateaus On Life And Activity Of Man :
The plateaus influence human activities in various ways :
Compared to mountain regions transport and communication network is developed in plateau areas and earning of a livelihood is easier. Thus human settlements are moderate in density.
Influence Of Plains On Life And Activity Of Man :
Plains are smooth for human habitation and easy living. The plains exert tremendous influence on human lives and activities. They may be enumerated in the following ways:
An important element as well as one of the basic elements of weather and climate is air pressure.
Air is made up of a number of mixed gases and it has weight. The weight of a column of air above a given place determines the air pressure at that place.
Air pressure is much more important than climatic control because small pressure changes are the cause of winds which may induce remarkable variations of general weather conditions. It is very significant in our daily life.
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Does air exert pressure?
All materials and all forms of life, including man are affected directly by the slight air pressure exerted on it.
Air exerts pressure from all directions but we do not feel this pressure because our body’s internal pressure is equal to that exerted by the atmosphere.
This is the reason why we do not feel internal or external pressure on ourselves.
Why does air exert pressure?
As the air has weight it exerts pressure on the earth’s surface. If a definite volume of air has many air molecules its weight or pressure will be high and if the same volume of air has few air molecules it’s weight or pressure will be low.
Molecules of a gas wander around loosely and often collide with each other.
When these molecules hit an object, the impact thus created is generally considered air pressure.
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The distance between molecules decreases with decreasing volume of the gas thus the density rises and so does the incidence of collision between the molecules, thereby increasing the pressure.
Is air pressure the same everywhere?
Like temperature air pressure is not the same at all places on the earth. It depends on altitude, temperature and the amount of water vapour in the air. The air pressure is maximum at sea level.
It decreases with the increase in height or altitude. This is because at great heights the air is thinner or less dense than the air at sea level.
The column of air at sea level is the highest. It decreases as we go higher. This decreased column of air exerts less pressure. Normally, the pressure of air at the sea level is 76 cm. but it decreases at the rate of 1 cm.
for every 110 metres of ascent. When the temperature of a place rises, the air expands. So it becomes less dense and exerts less pressure.
When the temperature falls, the air becomes denser and its pressure increases. For example, the pressure at the Equator is low while it is high around the poles.
Since the air pressure decreases with increasing altitudes and therefore the balance, between the outward pressure exerted by the air of the human body and the inward pressure exerted by the atmosphere is disturbed.
As the result, man suffers from nose and ear bleed at higher altitudes in the mountains.
Characteristics Of Air Pressure :
Causes Or Factors Of Variation Of Air Pressure
A study of the distribution of air pressure reveals that the air pressure is not uniformly distributed over the Earth’s surface air pressure varies from place to place and time to time due to the following causes/factors:
1. Temperature – As the air is heated it expands and rises upward. On the other hand cold air contracts and becomes heavier. Thus pressure has an inverse relation with temperature. High temperature causes a decrease in air pressure.
When the temperature decreases, the air becomes heavier and denser. Hence, it descends and as a result, air pressure increases.
For example, Equatorial regions have high temperatures throughout the year and therefore, they always have low pressure. On the other hand, the polar areas record low temperatures throughout the year.
Therefore, they always have high pressure.
2. Altitude – Generally air pressure decreases with increasing altitude because the lower layers of the atmosphere are the densest as the weight of all the layers above rests upon them.
The pressure decreases at the rate of one inch or 34. millibars for every 300 metres. The following table gives the standard relation between air pressure and altitude.
| Altitude in metre | Air Pressure in millibars |
| Sea Level | 1013.25 |
| 1000 | 898.76 |
| 2000 | 795.01 |
| 3000 | 701.21 |
| 4000 | 616.6 |
| 5000 | 540.48 |
| 10000 | 265 |
| 30000 | 11.85 |
It is estimated that about one-half of the atmospheric pressure lies up to a height of 5 km. There is a rapid decrease in pressure with increasing altitude. This fact is easily experienced by mountaineers.
Due to the drop in air pressure the boiling point of water drops in mountainous regions.
Their water starts boiling at a temperature below 100°C when the air pressure drops. So, it is difficult to ‘boil rice or anything for that reason.
As the air gets thinner with altitude oxygen in the air reduces too.
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So, mountaineers experience breathing and other troubles while they are scaling high peaks.
Due to low pressure, blood oozes out of their nostrils and their lungs work feverishly. If the air pressure is very low the mountaineers fall down and lose consciousness.
So, mountaineers have to carry oxygen cylinders to breathe freely when they’ll travel to very high altitudes.
3. Water vapour / Moisture-laden air – Water vapour in the air, often called vapour concentration on moisture-laden air is lighter than dry air. Therefore, dry air is heavier than wet or humid air.
Due to this reason, land winds are heavier than sea winds which are laden with water vapour.
As a result, low air pressure is generated by moisture-laden air and high air. pressure is generated by the dry air.
4. Rotation of the Earth – The rotation of the earth also causes differences in pressure. The earth’s rotation leads to the sinking of air in certain places and the ascent of air in other places.
The earth’s rotation is responsible for the formation of the sub-tropical high-pressure belt and the sub-polar low-pressure belt in each hemisphere.
Classification of Air pressure: There are two types of air pressure-
1. High Pressure – If a definite volume of air has many air molecules the weight or pressure will be high. If the barometer has an air pressure level of 1013-25 millibars or more the condition is known as ‘High Pressure’.
2. Low Pressure – If a definite volume of air has few molecules, its weight or pressure will be low. If it is 986 millibars or less it means Low Air Pressure.
| High Air Pressure | Low Air Pressure |
| 1. Any pressure higher than the surrounding air pressure is called a ‘high air pressure’. | 1. Any pressure less than the surrounding pressure is called a ‘low air pressure’. |
| 2. A high-air pressure area is usually cold and compacted. | 2. A low air pressure area is usually warm, light and expanding. |
| 3. High air pressure is found in cold temperate and polar regions. ‘ | 3. Low air pressure is found in the Equatorial and tropical regions. |
| 4. In high air pressure areas cold and heavy air naturally sinks towards the earth’s surface, gets denser and exerts higher pressure. | 4. In low air pressure areas warm and light air rises upwards and the ascent of air creates low pressure. |
| 5. In high-air pressure areas air is generally cold, dense and dry. | 5. In low-pressure areas air is generally hot and humid. |
| 6. Generally calm weather and clear sky prevail in high air pressure | 6. Cloudy, rainy, stormy and turbulent weather prevails in low-air pressure areas. |
The normal or standard air pressure at sea level is 1013-25 Mb (millibar). The unit of the force to measure air pressure is called a ‘bar’. A ‘bar’ is divided into 1000 millibars.
Millibar is a force equal to 1000 dynes per cm2 whereas a dyne is a unit of force approximately equal to the weight of one milligram or 29.92 inches or 76 cm.
At a temperature of 15° C at the latitude of 45. The common unit to measure air pressure is a millibar. Actual air pressure on the earth’s surface is found to vary between 940 and 1040 millibars.
Relation Between Different Units Of Air Pressure :
29.92 inches 1 inch
76 cms 1013-25 millibars
33-86 MB or 34 MB
1 cm = 13.3 MB.
The instrument used to measure air pressure is called a ‘barometer’. It was Torricelli, a disciple of Galileo, who first partially measured air pressure in 1643.
The simplest but most accurate instrument used for measuring air pressure is a mercury barometer.
It consists of a long narrow glass tube filled with mercury.
The tube is inverted and immersed in a vessel containing mercury. The pressure of the atmosphere on the mercury in the vessel is able to balance mercury.
Column of 76 cm in height. The mercury column is acting as an instrument for measuring the air pressure. Mercury is used in the barometer because it is the densest liquid.
This instrument is called an Ordinary Barometer or Torricellian Barometer. The most common barometer using mercury is called ‘Fortin’s barometer’.
Fortin reformed the ‘Ordinary Barometer’ to construct a better barometer. This barometer measures the air pressure very correctly but it has to be kept hanging by a nail in contact with the wall.
It is not convenient to take the barometer from one place to another. Nowadays air pressure is easily measured by an improved handy portable instrument called the Aneroid barometer.
An Aneroid barometer consists of a flat metal box with a vacuum chamber with expands or contracts as the air pressure changes.
The movements are picked up by levers which move the needle on the face of the instrument.
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It can be taken easily for fieldwork. So mountaineers, aircraft pilots and most other people use this barometer to find both air pressure and height climbed.
The continuous changes in air pressure are recorded by means of a curve drawn or scaled paper called a ‘barogram’.
A ‘barograph’ is a self-recording instrument which records changes in pressure by a curve on graph paper mounted on a rotating drum.
The altimeter is an instrument which helps to read the altitude of a place directly from its dial.
It works on the principle that the air pressure falls with altitude at a rate of about.11 MB per 100 metres of height.
Distribution Or Variation Of Air Pressure On The Earth :
Distribution or variation in air pressure in the atmosphere is not uniform over the earth’s surface. It varies vertically as well as horizontally.
Vertical Distribution Of Air Pressure :
The pressure exerted below from the overlying layers of air or that exerted from above to the air below is called vertical air pressure.
Near the earth’s surface air pressure is very high because it has to withstand the weight of the overlying layers of air.
Thus the air pressure gradually decreases upwards from the earth’s surface. In general, the air pressure decreases on an average at the rate of about 34 millibars per every 300 meters of height.
Horizontal Distribution Of Air Pressure :
The pressure exerted by moving horizontally is called horizontal air pressure. The distribution of air pressure across the latitudes is termed global horizontal distribution.
Its main feature is its zonal character known as ‘Pressure belts’.
On the earth’s surface, there are in all seven pressure belts.
Isobar is a combination of two words (Iso Equal and Bar Pressure). So isobars are linesIsobar is an imaginary line joining the places of equal air pressure at a particular time reduced to sea level.
If a place is 300 metres high and its actual pressure is 900 MB. Its pressure reduced to sea level would be 900+34 934 millibars because the pressure decreases at the rate of 34 millibars for every 300 metres.
Characteristics of Isobars :
The study of air pressure patterns on the globe is important as it is directly responsible to make the air move. It also decides the direction and pace of the movement of air.
Air moves from an area of high pressure to an area of low pressure.
The rate of change of the air pressure between two points on the earth’s surface is known as the ‘pressure gradient’.
When the movement of air is horizontal it is called wind. The wind velocity is high in an area of steep pressure gradient and it is low in an area of a gentle pressure gradient.
When the movement of air is vertical or nearly so, it is called an air current.
The direction of the wind is also influenced by the rotation of the earth.
The direction of the planetary winds is affected by the earth’s rotation and follows a simple pattern.
Periodical winds are felt only during certain times or during certain parts of the year. Local winds circulate over a comparatively small area.
Variable winds are mainly two types-Cyclones and anticyclones.
Winds rush towards the depression from all directions, called cyclones; they bring bad weather, rain storm, hail and snow which sometimes cause widespread destruction and loss of life. Anti-cyclones are gentle and bring fair weather with them.