6.Chapter 5.Geo.The Realms of the Earth
Chapter 5
Realms of the Earth Atmosphere
Realms of the Earth Atmosphere
You know
that our earth is a unique planet. It
consists of land, air and water as the major physical elements. Each element has its own realm or
domain. The earth can be divided into
four realms: the lithosphere (land), the hydrosphere (water), the atmosphere
(air) and the biosphere (life). In this
chapter, we shall learn about them.
Biosphere Hydrosphere Lithosphere
Do You Know? de lithos is a Greek word which means "stone 'or' rock's realms of the earth LITHOSPHERE -THE REALM OF LAND The upper surface of the earth, consisting of a thin layer of rock material, is called Lithosphere. It is found, both in the continents and on ocean floors. The continents form 29 per cent of the total crust of the earth. The rest is covered by oceans. The average height of the landmass of the earth is about 700 meters above the sea level. The land surface varies in height from place to place. Some parts of the earth are higher than 8000 meters while some other parts are only a few meters above mean sea level. Continental Crust Sedimentary Deposits Oceanic Crust.
Do You Know? 10 km 100 km The bottom of ocean floor is not the same everywhere.
The height of a place on the land is measured from the sea level.
Page 38 Continets
The large continuous masses of land above the sea level are called Continents. The landmass is divided into seven continents which are Asia, Africa, Europe, North America, South America Australia and Antarctica. Let us know more about them.
ASIA: It is the largest continent comprising of about 29.6 per cent of the earth's total land area. In the north, it touches the Arctic Ocean, which is very cold throughout the year. In the extreme south, the equator passes through some parts of this continent where temperature remains high throughout the year. It is bounded by the Pacific Ocean in the east and in the west, separated from Europe by the Ural mountains and Ural river. The continent is divided into several large and small countries. China and India are the two most populous countries Asia. It is a vast storehouse of agriculture and mineral resources.
Do you know? World Records of Asia
Largest lake Longest wall Longest railway line Deepest lake Caspian sea Great Wall of China Trans - Siberian railway Baikal
Page 39 Europe:
It is located to the west of AsiaEurope is much smaller in area than Asia.It cover of the total landmass. The Arctic Ocean lies to the north, the Mediterranean Sea to the Atlantic Ocean lies to the west of Europe. Almost all the countries of Europe are ver They are economically well developed with a high standard of living.
Africa: It is the second largest continent and the hottest continent. It is separated from Europe by the Mediterranean Sea
Do You Know? in the north. A very narrow piece of land Asia and Europe together is known a known Suez Isthamus, joins it with Asia Africa was called the Dark continent in the north - east. It has the famous Suez because people of other parts did no canal. The Atlantic Ocean is on its west much about this continent.and the Indian Ocean on its east. The Equator passes through the middle of Africa. However, the larger part of Africa lies in t Hemisphere. The Tropic of Cancer and the Tropic of Capricorn also pass through Africa of North Africa is a desert and a large area of Africa is covered with dense forests.
North America: It is the third largest continent and lies in the Northern Hemisphere. Ocean lies to the east and the Pacific Ocean to the west of the continent. The Arctic O its boundary in the north. The continent of North America is linked to South America stretch of land called the Isthamus of Panama. It has a Panama canal which joins the P with the Atlantic Ocean. Canada and USA are two major economically developed cour continent. e e ut y
South America: The larger part of it lies in the Southern Hemisphere. It is surrounded by Ocean in the east and the Pacific Ocean in the west. Brazil, Argentina and Chile are the maj in this continent. The longest mountain range - Andes, and Amazon basin - the largest the world, lie here.
Australia: This continent lies completely in the Southern Hemisphere. It is the smallest is surrounded by the Indian Ocean in the west and the Pacific Ocean in the east. The Sou in the south Australia is also known as the island continent, which is sparsely populated.
Do You Know? Australia is also known as Oceania Collectively it includes Australia, New Zealand New Guinea, the Melanesia and Polynesia groups. Oceania also includes Micronesia, a scattered group of islands that run along the northern and southern edges of the Euaqator.
Do You Know? de lithos is a Greek word which means "stone 'or' rock's realms of the earth LITHOSPHERE -THE REALM OF LAND The upper surface of the earth, consisting of a thin layer of rock material, is called Lithosphere. It is found, both in the continents and on ocean floors. The continents form 29 per cent of the total crust of the earth. The rest is covered by oceans. The average height of the landmass of the earth is about 700 meters above the sea level. The land surface varies in height from place to place. Some parts of the earth are higher than 8000 meters while some other parts are only a few meters above mean sea level. Continental Crust Sedimentary Deposits Oceanic Crust.
Do You Know? 10 km 100 km The bottom of ocean floor is not the same everywhere.
The height of a place on the land is measured from the sea level.
Page 38 Continets
The large continuous masses of land above the sea level are called Continents. The landmass is divided into seven continents which are Asia, Africa, Europe, North America, South America Australia and Antarctica. Let us know more about them.
ASIA: It is the largest continent comprising of about 29.6 per cent of the earth's total land area. In the north, it touches the Arctic Ocean, which is very cold throughout the year. In the extreme south, the equator passes through some parts of this continent where temperature remains high throughout the year. It is bounded by the Pacific Ocean in the east and in the west, separated from Europe by the Ural mountains and Ural river. The continent is divided into several large and small countries. China and India are the two most populous countries Asia. It is a vast storehouse of agriculture and mineral resources.
Do you know? World Records of Asia
Largest lake Longest wall Longest railway line Deepest lake Caspian sea Great Wall of China Trans - Siberian railway Baikal
Page 39 Europe:
It is located to the west of AsiaEurope is much smaller in area than Asia.It cover of the total landmass. The Arctic Ocean lies to the north, the Mediterranean Sea to the Atlantic Ocean lies to the west of Europe. Almost all the countries of Europe are ver They are economically well developed with a high standard of living.
Africa: It is the second largest continent and the hottest continent. It is separated from Europe by the Mediterranean Sea
Do You Know? in the north. A very narrow piece of land Asia and Europe together is known a known Suez Isthamus, joins it with Asia Africa was called the Dark continent in the north - east. It has the famous Suez because people of other parts did no canal. The Atlantic Ocean is on its west much about this continent.and the Indian Ocean on its east. The Equator passes through the middle of Africa. However, the larger part of Africa lies in t Hemisphere. The Tropic of Cancer and the Tropic of Capricorn also pass through Africa of North Africa is a desert and a large area of Africa is covered with dense forests.
North America: It is the third largest continent and lies in the Northern Hemisphere. Ocean lies to the east and the Pacific Ocean to the west of the continent. The Arctic O its boundary in the north. The continent of North America is linked to South America stretch of land called the Isthamus of Panama. It has a Panama canal which joins the P with the Atlantic Ocean. Canada and USA are two major economically developed cour continent. e e ut y
South America: The larger part of it lies in the Southern Hemisphere. It is surrounded by Ocean in the east and the Pacific Ocean in the west. Brazil, Argentina and Chile are the maj in this continent. The longest mountain range - Andes, and Amazon basin - the largest the world, lie here.
Australia: This continent lies completely in the Southern Hemisphere. It is the smallest is surrounded by the Indian Ocean in the west and the Pacific Ocean in the east. The Sou in the south Australia is also known as the island continent, which is sparsely populated.
Do You Know? Australia is also known as Oceania Collectively it includes Australia, New Zealand New Guinea, the Melanesia and Polynesia groups. Oceania also includes Micronesia, a scattered group of islands that run along the northern and southern edges of the Euaqator.
Page 40.
This continent lies in the southern - most part of the Southern Hemisphere. It is stretch around the South Pole up to the Antarctic Circle. In the north, it is surrounded by Southern Om The continent is covered with very thick sheets of ice and snow. It is estimated that three - fourth the total mass of ice of the earth is found in Antarctica Due to very cold conditions, the is not inhabited by human beit
Do You Know? Scientists of some countriesti in Antarctica the first two permanent research bases established their research centers of India are 'Dakshin Gangotri' and 'Maitri! India has also established its resea center in Antarctica,
Major Landforms the surface of the land is not uniform everywhere. Some parts of the earth are high above sea level and have steep slopes and rough surface but some parts are smooth and flat with geni slopes. The difference in the height and slopes of the land surface is known as the Relief or Landforms. The major landforms are grouped as mountains, plateaus and plains.
Mountains: A mountain or a hill is an uplifted portion of the land surface. The upper most p or portion of a mountain or a hill forms the peak. Most of the mountains are arranged in a line call a range, which has a series of peaks and valleys.
The old mountains are those which have been worn down by the forces of nature and do have sharp peaks. The Aravalli range in India, the Ural mountains in Russia and the Appalachians USA are the examples of old mountains.
The young mountains were formed during the recent phase of mountain building, about 25 million years ago.
They are very high and their sharp peaks are covered with snow. The Himalayas in Asia, the Alps in Europe, the Andes in South America and the Rockies in North America are important young mountains.
This continent lies in the southern - most part of the Southern Hemisphere. It is stretch around the South Pole up to the Antarctic Circle. In the north, it is surrounded by Southern Om The continent is covered with very thick sheets of ice and snow. It is estimated that three - fourth the total mass of ice of the earth is found in Antarctica Due to very cold conditions, the is not inhabited by human beit
Do You Know? Scientists of some countriesti in Antarctica the first two permanent research bases established their research centers of India are 'Dakshin Gangotri' and 'Maitri! India has also established its resea center in Antarctica,
Major Landforms the surface of the land is not uniform everywhere. Some parts of the earth are high above sea level and have steep slopes and rough surface but some parts are smooth and flat with geni slopes. The difference in the height and slopes of the land surface is known as the Relief or Landforms. The major landforms are grouped as mountains, plateaus and plains.
Mountains: A mountain or a hill is an uplifted portion of the land surface. The upper most p or portion of a mountain or a hill forms the peak. Most of the mountains are arranged in a line call a range, which has a series of peaks and valleys.
The old mountains are those which have been worn down by the forces of nature and do have sharp peaks. The Aravalli range in India, the Ural mountains in Russia and the Appalachians USA are the examples of old mountains.
The young mountains were formed during the recent phase of mountain building, about 25 million years ago.
They are very high and their sharp peaks are covered with snow. The Himalayas in Asia, the Alps in Europe, the Andes in South America and the Rockies in North America are important young mountains.
Page 41
Do you know?
Mount Everest is the highest peak of the world and it lies in Himalaya mountains. Its height is 8850 meters above the sea level. It is located in Nepal.
Do You Know? Plateaus generally have better means of as compared to the mountains.
2 Plateaus: A plateau is an upland with rugged surface. It is like a tableland uplifted from its surrounding the average height of a plateau is 600 meters above the sea level.Nearly 40 transport per cent of total land surface of the earth is plateau, The Plateau of Tibet also called Roof of the World, is the highest plateau in the world. Its average height is about 5000 meters above the mean sea level. The Deccan Plateau in India, the Arabian Plateau and the Brazil Plateau are some of the large plateaus of the world. Most of the plateaus are the storehouses of minerals, such as iron - ore, gold, etc.
Plains: A plain is a relatively low - lying flat land.The slope of a plain is gentle and its average height is between 100 and 200 meters above the sea level. Most of the plains in the world have been formed by rivers. The rivers carry away large volume of silt and sediments from the mountains and deposit them in low - lying areas to form plains. The Northern Plains of India has been formed by the Ganga river system. Other important plains are the Great Northern Plains China Plain, the Egyptian Plain and the Plain of Iraq. Plains are densely populated as they have fertile soil, abundant supply of water and an ideal climate.
ATMOSPHERE THE REALM OF AIR
Atmosphere is the vast expanse of air surrounding the earth on all sides. It is held with the earth by the gravitational force. It contains several gases, such as Nitrogen, Oxygen, Carbon Dioxide, etc. which are essential for life on the earth, 18 per cent volume of gas in the atmosphere is Nitroger Oxygen is about 21 per cent of the total volume. These two gases constitute about 99 percent.
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of the total volume of the atmospheric air. Both these gases are very essential for the biosphere to exist. It is nitrogen that dilutes oxygen and prevents rapid burning at the earth's surface whereas oxygen is essential for respiration and burning. The amount of carbon dioxide, although very minute, i.e. 0.03 per cent, is a very important part of the composition of Atmosphere atmosphere. It keeps the earth warm. The ozone layer in the atmosphere protects all forms of life on the earth from the harmful
Do You Know? radiation of the sun. The remaining gases are argon, hydrogen, helium, etc. The atmosphere serves as the medium for fast Besides the gases, water vapors and air transport and virtual communication. particles of dust are also present in the atmosphere. These are found varying quantities in the lower layers of the atmosphere. They responsible for the varying weather conditions on the earth. Although the atmosphere extends up to 1600 km, the density of the air near the earth's surfa is the highest. As you go higher, the density of air decreases rapidly.
HYDROSPHERE THE REALM OF WATER Hydrosphere refers to the layer of water on the surface of the earth, below the surface of the ea and also in the air. Water covers about two - thirds of the total surface of the earth. Therefore, earth, sometimes, is called the Watery Planet, the largest part of the earth is covered by ocean
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Water is present in the form of ice sheets in polar regions and on high mountains. Water also occurs on land in the form of lakes and rivers.) Waicon is very very important living Hugs ce Whaman beings and animal mirco erg pisanicu Oceans wela leving thing camot ord so Hy do Syphoo's up the oceans cover about 71 per cent of the total surface of the earth. The vast expanse of water is in the form of five oceans - the Pacific, the Atlantic, the Indian, the Arctic and the Southern (Antarctic) ocean. Let us learn more about each of them.
The Pacific Ocean: This ocean is the largest. It covers about one - third of the earth's surface. This ocean is surrounded by four continents, i.e. North America, South America, Asia and Antractic. The Pacific is the deepest of all oceans. The average depth of the major portion of this ocean is about 7300 meters.
The Atlantic Ocean: It is about half of the size of the Pacific Ocean. It covers about one - sixth of the total surface of the earth. It has two developed continents on its two sides, i.e. Europe in the east and North America in the west.
The Indian Ocean: It is smaller than the Pacific and the Atlantic Ocean. It is bounded by the continents of Asia, Africa and Australia. It is the only ocean which has been named after a country - India.
The Arctic Ocean: This ocean lies within the Arctic Circle and has North Pole in its center. The Pacific and the Atlantic Oceans merge into it in the north. Asia, Europe and North America make their northern boundaries with this ocean.
The Arctic Ocean remains frozen for a larger part of the year. The Southern (Antarctic) Ocean:
The Southern Ocean is a fourth largest ocean around Antarctic. This occupies about 20 per cent of the surface area of the global ocean.
BIOSPHERE The biosphere refers to a narrow zone, Biosphere Atmosphere which is very close to the earth's surface on the land, water and air. It comprises of all forms of organisms. It consists of animals, plants and micro-organisms. Biosphere exists where the upper part of the lithosphere, the lower part of the atmosphere and the hydrosphere come in contact with one another. All plants, animals and micro - organisms Biosphere live together in their physical environment Lithosphere and interact with each other. They are the limits of the Biosphere interdependent for their survival. Life exists only about 9 km above the earth and about 11 km below
Page 44.
the
ocean surface. It is this sphere where
four non - living elements - land, water, air and sunlight present
the physical conditions on the earth vary from place to place and are responsible for a variety life forms on different parts of the earth. Plants and animals also vary in their size and shape. Thi differ from place to place as they require a certain habitat for their growth and survival.
All plants and animals maintain a balance in a region. It is the human being who interfer and creates imbalance between the plants and animals. As the human population is increasing rapidly, more space is required for different human activities, such as agriculture, industry and urbanisation.
Man is destroying the forests carelessly and exploiting the resources, as a result of these activities, several problems have emerged before human beings, for example, soil erosion, floods, etc. Besides these, pollution of air and water has increased beyond the point of control. Effects of urbanisation keywords interdependent: depending on one another for survival or existence. isthmus: it is a narrow strip of land that joins two large areas of land. It is always surrounded by seat either side. ozone layer: the layer present in stratosphere around 15 to 30 km above the surface of the earth. This layer protects earth from harmful ultraviolet radiation of the sun. sea level: the level of the surface of the sea with respect to the land. It is taken as a mean level between high and low tide, and used as a standard base for measuring heights and depths.
the physical conditions on the earth vary from place to place and are responsible for a variety life forms on different parts of the earth. Plants and animals also vary in their size and shape. Thi differ from place to place as they require a certain habitat for their growth and survival.
All plants and animals maintain a balance in a region. It is the human being who interfer and creates imbalance between the plants and animals. As the human population is increasing rapidly, more space is required for different human activities, such as agriculture, industry and urbanisation.
Man is destroying the forests carelessly and exploiting the resources, as a result of these activities, several problems have emerged before human beings, for example, soil erosion, floods, etc. Besides these, pollution of air and water has increased beyond the point of control. Effects of urbanisation keywords interdependent: depending on one another for survival or existence. isthmus: it is a narrow strip of land that joins two large areas of land. It is always surrounded by seat either side. ozone layer: the layer present in stratosphere around 15 to 30 km above the surface of the earth. This layer protects earth from harmful ultraviolet radiation of the sun. sea level: the level of the surface of the sea with respect to the land. It is taken as a mean level between high and low tide, and used as a standard base for measuring heights and depths.
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