• Life of the people of the Amazon basin is slowly changing.
→ Amazon highway made all parts of the rainforest accessible.
→ Aircrafts and helicopters are also used for reaching various places.
→ The indigenous population was pushed out from the area and forced to settle in new areas where they continued to practice their distinctive way of farming.
• The developmental activities are leading to the gradual destruction of the biologically diverse rainforests.
Life in the Ganga-Brahmapura Basin
• The tributaries of rivers Ganga and Brahmaputra together form the Ganga-Brahmaputra basin in the Indian subcontinent.
→ The basin lies in the sub-tropical region that is situated between 10°N to 30°N latitudes.
• The tributaries of the River Ganga like the Ghaghra, the Son, the Chambal, the Gandak, the Kosi and the tributaries of Brahmaputra like Dibang River, Lohit River, Teesta, Manas drain it.
• Main features of the basin: The plains of the Ganga and the Brahmaputra, the mountains and the foothills of the Himalayas and the Sundarbans delta.
Climate
• The area is dominated by monsoon climate.
→ The monsoon brings rains from mid-June to mid-September.
• The summers are hot and the winters cool.
Topography
• The basin area has varied topography.
• The mountain areas with steep slopes have inhospitable terrain therefore, less number of people in the mountain area.
• Agriculture is the main occupation of the people in the plains because soil is fertile.
• Settlements are places where people build their homes.• Settlements can be of two types:
→ Temporary: Settlements which are occupied for a short time are called temporary settlements. Example: The people living in deep forests, hot and cold deserts and mountains.
→ Permanent: Settlements which are made to live in for a long time are called permanent settlements. Example: People build homes to live in.
Rural Settlements
• The villages are rural settlement where people are engaged in activities like agriculture, fishing, forestry, crafts work and trading etc.
• Rural settlements can be compact or scattered.
→ A compact settlement is a closely built area of dwellings, wherever flat land is available.
→ In a scattered settlement dwellings are spaced over an extensive area. This type of settlement is mostly found in hilly tracts, thick forests, and regions of extreme climate.
• In rural areas, people build houses to suit their environment. → In regions of heavy rainfall – houses have slanting roofs. → In regions where water accumulates in the rainy season – houses are constructed on a raised platform or stilts.
→ In the areas of hot climate – Thick mud walled houses with thatched roofs.
Urban Settlements
• The towns are small and the cities are larger urban settlements.
• In urban areas the people are engaged in manufacturing, trading, and services.
Transport
• Transport is the means by which people and goods move.
• In early days, People had to walk and used animals to carry their goods.
• With the passage of time different means of transport developed but even today people use animals for transport.
→ In India donkeys, mules, bullocks and camels are common.
→ In the Andes Mountains of South America, llamas are used.
→ In Tibet, yaks are used.
• The four major means of transport are:
→ Roadways
→ Railways
→ Waterways
→ Airways
Roadways
• Roads are most commonly used means of transport especially for short distances.
• Roads are also present in terrains like deserts, forests and even high mountains.
→ Manali-Leh highway in the Himlayan Mountains is one of the highest roadways in the world.
• Roads built underground are called subways/under paths.
• Flyovers are built over raised structures.
Railways
• The railways carry heavy goods and people over long distances quickly and cheaply.
• Today, Diesel and electric engines have largely replaced the steam engines.
In places super fast trains have been introduced to make the journey faster.
• The railway network is well developed over the plain areas.
• With the advanced technological skills railway lines are also bein laid in difficult mountain terrains also. Howver these are lesser in numbers.
• Indian railway network is well developed and largest in Asia.
Waterways
• Waterways are the cheapest for carrying heavy and bulky goods over long distances.
• These are mainly of two types
→ Inland waterways
→ Sea routes
Inland Waterways
• Navigable rivers and lakes are used as inland waterways.
• Important inland waterways: Ganga-Brahmaputra river system, the Great Lakes in North America and the river Nile in Africa.
Sea Routes
• Sea routes and oceanic routes are mostly used for transporting merchandise and goods from one country to another.
→ These routes are connected with the ports.
• Important ports of the world: Singapore and Mumbai in Asia, New York, Los Angeles in North America, Rio de Janerio in South America, Durban and Cape Town in Africa, Sydney in Australia, London and Rotterdam in Europe.
Airways
• Airways is the fastest way of transport developed in the early twentieth century.
• It is also the most expensive due to high cost of fuels.
• Air traffic is adversely affected by bad weather like fog and storms.
• It is the only mode of transport to reach the most remote and distant areas especially where there are no roads and railways.
• Helicopters are extremely useful in most inaccessible areas and in time of calamities for rescuing people and distributing food, water, clothes and medicines.
• Important airports are Delhi, Mumbai, New York, London, Paris, Frankfurt and Cairo.
Communication
• Communication is the process of conveying messages to others.
• The advancement in the field of communication has brought about an information revolution in the world.
• Different modes of communication are used to provide information, to educate as well as to entertain.
• Newspapers, radio and television are called mass media as they can communicate with a large number of people.
Satellites
• The satellites have made communication even faster.
• Satellites have helped in oil exploration, survey of forest, underground water, mineral wealth, weather forecast and disaster warning.
• Wireless telephonic communications through cellular phones have become very popular today.
Internet
• We can send electronic mails or e-mails through Internet.
• Internet provides us with worldwide information and interaction
• We can also reserve tickets for railways, airways and even cinemas and hotels sitting at home.
• Natural Vegetation refers to the plant life of a region which grown naturally.
• The type and thickness of natural vegetation varies from place to place because of the variation in these factors.
• Natural Vegetation is classified into three broad categories:
→ Forests: Which grow where temperature and rainfall are plentiful to support a tree cover. → Grasslands: Which grow in the region of moderate rain. → Shrubs: Thorny shrurbs and scrubs grow in the dry region.
• The changes in the type of natural vegetation occur mainly because of the changes of climatic condition.
Forests
Tropical Evergreen Forests
• Also called tropical rainforests.
• These thick forests occur in the regions near the equator and close to the tropics.
• These regions are hot and receive heavy rainfall throughout the year.
• As there is no particular dry season, the trees do not shed their leaves altogether. Thus, they are called evergreen.
• Common trees: Hardwood trees like rosewood, ebony, mahogany.
Tropical Deciduous Forests
• These are monsoon forests found in the large part of India, northern Australia and in central America.
• Trees shed their leaves in the dry season to conserve water.
• Common trees: Hardwood trees like sal, teak, neem and shisham.
• Common Animals: Tigers, lions, elephants, langoors and monkeys.
• Importance of Hardwood trees:
→ useful for making furniture, transport and constructional materials.
Temperate Evergreen Forests
• These forests are located in the mid-latitudinal coastal region.
• Commonly found along the eastern margin of the continents, e.g., In south east, USA, South China and in South East Brazil.
• Common trees: both hard and soft wood trees like oak, pine, eucalyptus, etc.
• These are found in the north eastern part of USA, China, New Zealand, Chile and also found in the coastal regions of Western Europe.
• They shed their leaves in the dry season.
• Common trees: Oak, ash, beech, etc.
• Common animals: Deer, foxes, wolves
• Birds like pheasants, monals are also found here.
Mediterranean Vegetation
• These are present at west and south west margins of the continents.
• It is mostly found in the areas around the Mediterranean sea in Europe, Africa and Asia which given its name.
• It is also found outside the actual Mediterranean region in California in the USA, south west Africa, south western South America and South west Australia.
• These are found in the areas of hot dry summers and mild rainy winters.
• Common vegetation: Citrus fruits such as oranges, figs, olives and grapes.
• There isn’t much wildlife here. Coniferous Forests
• These trees are found in higher latitudes (50° – 70°) of Northern hemisphere.
• These are also called as Taiga.
• These forests are also seen in the higher altitudes.
• Common trees: Chir, pine, cedar
• Common animals: Silver fox, mink, polar bear.
• Trees are tall, softwood evergreen trees.
→ The woods of these trees are very useful for making pulp, which is used for manufacturing paper and newsprint.
→ Match boxes and packing boxes are also made from softwood.
Grasslands
Tropical grasslands
• These occur on either side of the equator and extend till the tropics.
• This vegetation grows in the areas of moderate to low amount of rainfall.
• The grass can grow very tall, about 3 to 4 metres in height.
• Example: Savannah grasslands of Africa.
• Common animals: Elephants, zebras, giraffes, deer, leopards.
Temperate grasslands
• These are found in the mid- latitudinal zones and in the interior part of the continents.
• Grass here is short and nutritious.
• Common animals:Wild buffaloes, bisons, antilopes.
Thorny bushes
• These are found in the dry desert like regions which are located on the western margins of the continents.
• The vegetation cover is scarce because of scanty rain and scorching heat.
Polar region
• This place is extremely cold.
• The growth of natural vegetation is very limited here.
• Only mosses, lichens and very small shrubs are found here which grows during the very short summer.
→ This is called Tundra type of vegetation.
• This vegetation is found in the polar areas of Europe, Asia and North America.
• The animals have thick fur and thick skin to protect themselves from the cold climatic conditions.
• Common animals: Seal, walruses, musk-oxen, Arctic owl, Polar bear and snow foxes.
• The sun’s heat causes evaporation of water vapour.
• When the water vapour cools down, it condenses and forms clouds.
• From there it may fall on the land or sea in the form of rain, snow or sleet.
• The process by which water continually changes its form and circulates between oceans, atmosphere and land is known as the water cycle.
Terrarium: It is an artificial enclosure for keeping small house plants.
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• The major sources of fresh water are the rivers, ponds, springs and glaciers.
• The ocean bodies and the seas contain salty water as it contains large amount of dissolved salts. → Most of the salt is sodium chloride or the common table salt that we eat.
Distribution of Water Bodies
• Saline Water → Oceans: 97.3 %
• Fresh Water → Ice-caps: 02.0 % → Ground Water: 0.68 % → Fresh Water Lakes: 0.0009 % → Inland seas and salt lakes: 0.0009 % → Atmosphere: 0.0019 % → Rivers: 0.0001 %
Ocean Circulation
• Ocean water keeps moving continuously and never still.
• The movements that occur in oceans can be broadly categorised as: → Waves → Tides → Currents
Waves
• When the water on the surface of the ocean rises and falls alternately, they are called waves.
• An earthquake, a volcanic eruption or underwater landslides can shift large amounts of ocean water. As a result a huge tidal wave called tsunami.
→ The largest tsunami ever measured was 150m. high. These waves travel at a speed of more than 700 km. per hour.
→ The tsunami of 2004 caused wide spread damage in the coastal areas of India. The Indira point in the Andaman and Nicobar islands got submerged after the tsunami.
• The rhythmic rise and fall of ocean water twice in a day is called a tide.
→ When water covers much of the shore by rising to its highest level, it is high tide.
→ When water falls to its lowest level and recedes from the shore, it is low tide.
• Cause of tides: The strong gravitational pull exerted by the sun and the moon on the earth’s surface.
→ The water of the earth closer to the moon gets pulled under the influence of the moon’s gravitational force and causes high tide.
• Spring Tides: During the full moon and new moon days, the sun, the moon and the earth are in the same line and the tides are highest. These tides are called Spring Tides.
• Neap Tides: When the moon is in its first and last quarter, the ocean waters get drawn in diagonally opposite directions by the gravitational pull of sun and earth resulting in low tides. These tides are called neap tides.
• Importance of Tides:
→ High tides help in navigation. They raise the water level close to the shores which helps the ships to arrive at the harbour more easily.
→ The high tides also help in fishing as many more fish come closer to the shore during the high tide.
→ The rise and fall of water due to tides is being used to generate electricity in some places.
Ocean currents
• The streams of water flowing constantly on the ocean surface in definite directions are called ocean currents.
• Ocean currents are of two types: → Warm Ocean Currents: These ocean currents originate near the equator and move towards the poles. Example: Gulf Stream. → Cold Ocean Currents: These ocean currents carry water from polar or higher latitudes to tropical or lower latitudes. Example: The Labrador Ocean current.
• Importance of Ocean Currents: → The ocean current influence the temperature conditions of the area. Warm currents bring about warm temperature over land surface. → The areas where the warm and cold currents meet provide the best fishing grounds of the world. Seas around Japan and the eastern coast of North America are such examples.
• The areas where a warm and cold current meet also experience foggy weather making it difficult for navigation.
• A huge blanket of air that surrounds earth is called atmosphere.
• It provides us the air we breathe and protects us from the harmful effects of the sun’s rays which is essential for our survival. Composition of the Atmosphere
• Nitrogen and oxygen are two gases which make up the bulk of the atmosphere.
• Carbon dioxide, helium, ozone, argon and hydrogen are found in lesser quantities.
• Apart from these gases, tiny dust particles are also present in the air.
• Percentage of different constituents of air: → Nitrogen: 78 % → Oxygen: 21 % → Argon: 0.93 % → Carbon Dioxide: 0.03 % → All Others: 0.04 %
• Nitrogen:
→ Plants need nitrogen for their survival. They can not take nitrogen directly from the air. Bacteria, that live in the soil and roots of some plants, take nitrogen from the air and change its form so that plants can use it.
• Oxygen:
→ Humans and animals take oxygen from the air as they breathe.
→ Green plants produce oxygen during photosynthesis which make oxygen content in the air
remains constant.
• Carbon Dioxide:
→ Green plants use carbon dioxide to make their food and release oxygen.
→ Humans or animals release carbon dioxide which is equal to the amount used by the plants which make a perfect balance.
→ However, the balance is upset by burning of fuels, such as coal and oil which result in increased volume of carbon dioxide that affecting the earth’s weather and climate.
Structure of Atmosphere
• Atmosphere is divided into five layers starting from the earth’s surface:
→ Troposphere
→ Stratosphere
→ Mesosphere
→ Thermosphere
→ Exosphere
Troposphere
• Most important layer as the air we breathe exists here and almost all the weather phenomena like rainfall, fog and hailstorm occur in this layer.
• Its average height is 13 km.
Stratosphere
• It lies above the troposphere.
• It extends up to a height of 50 km.
• This layer is almost free from clouds and associated weather phenomenon, making conditions most ideal for flying aeroplanes.
• It contains a layer of ozone gas which protects us from the harmful effect of the sun rays.
Mesosphere
• Third layer of the atmosphere which lies above the stratosphere.
• It extends up to the height of 80 km.
• Meteorites burn up in this layer on entering from the space.
Thermosphere
• Temperature rises very rapidly with increasing height in this layer.
• Ionosphere is a part of this layer.
• It extends between 80-400 km.
• This layer helps in radio transmission.
Exosphere
• The upper most layer of the atmosphere is known as exosphere.
• This layer has very thin air.
• Light gases like helium and hydrogen float into the space from here.
Weather and Climate
• Weather is this hour-to-hour, day to day condition of the atmosphere.
→ It can change dramatically from day to day.
• The average weather condition of a place for a longer period of time represents the climate of a place.
Temperature
• The degree of hotness and coldness of the air is known as temperature.
• The temperature of the atmosphere changes not only between day and night but also from season to season.
• Insolation is an important factor that influences the distribution of temperature. → Insolation is the incoming solar energy intercepted by the earth. → The amount of insolation decreases from the equator towards the poles. Therefore, the temperature decreases in the same manner.
• Temperature in cities is much higher than that of villages. → The concrete and metals in buildings and the asaphalt of roads get heated up during the day which is released during the night.
Air Pressure
• Air pressure is defined as the pressure exerted by the weight of air on the earth’s surface. • The air pressure is highest at sea level and decreases with height. → Horizontally the distribution of air pressure is influenced by temperature of air at a given place. • Where temperature is high the air gets heated and rises which creates a low-pressure area. → Low pressure is associated with cloudy skies and wet weather.
• Where temperature is low, the air is cold and therefore, heavy. Heavy air sinks and creates a high pressure area. → High pressure is associated with clear and sunny skies.
• The air always moves from high pressure areas to low pressure areas.
Wind
• The movement of air from high pressure area to low pressure areas is called wind.
• Winds can be broadly divided into three types:
→ Permanent winds: The trade winds, westerlies and easterlies are the permanent winds. These blow constantly throughout the year in a particular direction.
→ Seasonal winds: These winds change their direction in different seasons. For example monsoons in India.
→ Local winds: These blow only during a particular period of the day or year in a small area. For example, land and sea breeze.
The hot and dry local wind of northern planes of India is called loo.
Moisture
• When water evaporates from land and different water bodies, it becomes water vapour.
• Moisture in the air at any time, is known as humidity.→ When the air is full of water vapour we call it a humid day.
• As the air gets warmer, its capacity to hold the water vapour increases and so it becomes more and more humid.
• When the water vapour rises, it starts cooling.
→ The water vapour condenses causing formation of droplets of water. Clouds are just masses of such water droplets.
→ When these droplets of water become too heavy to float in air, then they come down as precipitation.
→ Precipitation that comes down to the earth in liquid form is called rain.
• There are three types of rainfall:
→ the convectional rainfall
→ the orographic rainfall
→ the cyclonic rainfall
• Importance of Rainfall:
→ It is very important for the survival of plants and animals.
→ It brings fresh water to the earth’s surface.
• If rainfall is less – water scarcity and drought occur. On the other hand if it is more, floods take place.
Our Changing Earth Class 7 Notes Social Science Geography Chapter 3
The lithosphere is broken down into a number of plates known as the Lithosphere plates.
The movement of these plates causes changes on the surface of the earth. The forces that act in the interior of the earth are called endogenic forces, while the forces that work on the surface of the earth are called exogenic forces.
Endogenic force causes earthquakes and volcanic eruptions.
Exogenic force causes weathering, erosion, deposition and gradation.
Weathering is the breaking up of the rocks on the earth’s crust.
Erosion is the breaking away of the landscape by different agents like water, wind and ice.
Sudden movements like earthquake and volcanoes cause most destruction over the surface of the earth.
A volcano is a vent (opening) in the earth’s crust through which molten material erupts suddenly.
The vibration in the plates of earth is called an earthquake.
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The place in the crust where the movement starts is called the focus.
The place on the surface above the focus is called the epicenter.
It is measured by seismograph and intensity is measured by Richter scale.
Although earthquakes cannot be predicted, the impact can certainly be minimized.
Major Landforms
The landscapes are continuously worn away by two forces, weathering and erosion.
Weathering is the breaking down of the rocks on the earth’s surface.
Erosion is the wearing away of the landscape by different agents like water, wind and ice.
Work of a River
When the river tumbles at a steep angle over hard rocks or down a steep valley side, it forms a waterfall.
As the river enters the plain, it twists and turns, forming large bends known as meanders.
At this point of time, the meander loop cuts off from the river and forms a cut-off called an ox-bow lake.
During flooding, the river deposits layer of fine soil and other materials called sediments along its banks. This leads to the formation of a flat fertile plain called flood plain.
The raised banks along the river are called levees.
The collection of sediments from all the mouths forms a delta.
Work of Sea Waves
The erosion and deposition of the sea waves give rise to coastal landforms.
Due to sea waves, hollow caves are formed on the rocks. They are called sea caves.
As cavities become bigger in size, only the roof of the caves remains, thus forming sea arches.
The erosion further breaks the roof and only walls are left. It is called stacks.
The steep rocky coast rising almost vertically above seawater is called sea cliff.
Work of Ice
Glaciers are rivers of ice which erode the landscape by bulldozing soil and stones to expose the solid rocks below.
The materia] carried by the glaciers, such as big and small rocks, sand and silt get deposited. These deposits form glacial moraines.
Work of Winds
An active agent of erosion and deposition in the deserts is wind. It makes rocks in shape of a mushroom, called mushroom rocks.
When the wind stops blowing, the sand falls and get deposited in low hill-like structures. These are called sand dunes.
When the grains of sand is very fine and light, the wind can carry it over long distances. When such sand is deposited in large areas, it is called loess.
The lithosphere is broken into numerous plates known as the lithospheric plates. These plates move around very slowly. The movement of these plates causes changes on the surface of the earth.
The earth movements are divided on the basis of the forces which cause them.
The forces which work on the surface of the earth are called as exogenic forces.
Endogenic forces sometimes produce sudden movements which cause earthquakes and volcanoes.
A volcano is an opening in the earth’s crust through which molten material erupts suddenly.
When the lithospheric plates move, the surface of the earth vibrates. The vibrations can travel all round the earth. These vibrations are known as earthquakes.
The place in the crust where the movement starts is known as the focus.
The epicentre of the earthquake is the place on the surface above the focus.
Maximum damage occurs near the epicentre.
Some common earthquake prediction methods include studying animal behaviour, fish in the ponds get agitated, snakes come to the surface.
The damage caused due to earthquakes can be minimised if we are prepared beforehand.
During an earthquake, one can take shelter under a kitchen counter, table or desk, against an inside corner or wall. One should be away from fireplaces, areas around chimneys, windows, etc.
Weathering and erosion are two processes due to which the landscape is being continuously worn away.
Weathering is the breaking up of the rocks on the earth’s surface. Erosion is the wearing ‘ away of the landscape by different agents like water, wind, etc.
When the river tumbles at a steep angle over very hard rocks or down a steep valley side it forms a waterfall.
Large bends formed by twisting and turning of the river while entering the plain are called meanders.
An oxbow lake is a cut-off lake formed due to cut off of a meander loop.
Flood plains are fertile areas formed by the deposition of fine soil and other material (sediments) during floods.
Levees are the raised banks of the rivers.
The streams which distribute the waters of a river are known as distributaries.
The triangular deposits at the mouth of a river from the delta, which is very fertile.
The erosion and deposition of the sea waves give rise to coastal landforms.
Hallow like caves are formed on the rocks at the coast due to erosional work of sea waves. These formations are called sea caves. When these cavities become very big, only the roof of the caves remains, forming sea arches.
This roof sometimes breaks due to erosion and thus only walls are left. These wall-like features are known as stacks.
The steep rocky coast rising almost vertically above seawater is called sea cliff.
The sea waves deposit sediments along the shores forming beaches.
The landscape is eroded due to glaciers which are rivers of ice. The material carried by the glacier such as rocks, sand and silt gets deposited and forms glacial moraines.
The wind is an active agent of erosion and deposition in the deserts. When the wind blows, it lifts and transports said from one place to another. When it stops blowing the sand falls and gets deposited in low hill-like structures known as sand dunes.
When very fine and light and gets deposited in large areas, it called loess.
Endogenic forces: The forces that act in the interior of the earth are called endogenic forces.
Exogenic forces: The forces that act on the surface of the earth are called as exogenic forces.
Earthquake: The vibrations caused by the movement of the lithospheric plates are called earthquakes.
Focus: The place in the crust where the movement starts is called the focus.
Epicentre: The place on the surface above the focus is called the epicentre.
Weathering: The breaking up of the rocks on the earth’s surface is known as weathering.
Erosion: The wearing away of the landscape by different agents like water, wind and ice is called erosion.
Waterfall: A place where a river or stream fails from a high place for example over a cliff or rock is known as waterfall.
Meander: Large bends formed by the twisting and turning of a river while entering a plain are known as meanders.
Floodplains: Floodplains are areas where fine soil and other material get deposited during floods. These are very fertile.
Levees: The raised banks of a river is known as levees.
Distributary: As the river approaches the sea, the speed of the flowing water decreases and the river begins to break up into a number of streams called distributaries.
Delta: It is a triangular area of land where a river has split into many smaller rivers before entering the sea.
Sea caves: Sea caves are hollow like caves formed on the rocks.
Sea arches: When the cavities become very big, only the roof of the caves remains known as sea arches.
Stacks: Further erosion breaks the roof and only wall-like features remain. These features are called stacks.
Seacliff: The steep rocky coast rising almost vertically above seawater is called sea cliff.
Beaches: The sea waves deposit sediments along the shores to form beaches.
Mushroom rocks: In deserts, rocks in the shape of a mushroom are very common. These are called mushroom rocks.
Sand dunes: In deserts, when the winds stop blowing, the sand falls and gets deposited in low hill-like structures known as sand dunes.
Loess: When very fine and light grains of sand gets deposited in large areas, it is called loess.
The earth comprises three layers: crust, mantle and core.
Constant changes take place inside as well as outside the earth.
What is the Interior of the Earth?
The earth is made up of three concentric layers-crust, mantle and core.
The uppermost layer over the earth’s surface is called the crust. It is about 35 km thick on the continental masses and only 5 km thick on the ocean floor. It is made up of silica and alumina and thus called sial.
The oceanic crust mainly consists of silica and magnesium called sima. Just below the crust is the mantle up to an extent of 2,900 km.
The innermost layer is the core with a radius of 3,500 km. As it is made of nickel and iron, it is called nife(ni-nickel and fe-ferrous i.e. iron). The central core has a very high temperature and pressure.
Rocks and Minerals
The earth’s crust is made of various types of rocks. Any natural mass of mineral matter that makes up the earth’s crust is called a rock.
There are three major types of rocks; igneous rocks, sedimentary rocks and metamorphic rocks.
When the molten magma cools, it becomes solid. Rocks thus formed are called igneous or primary rocks. They are of two types, extrusive igneous rocks and intrusive igneous rocks.
Rocks roll down and break into small fragments and these smaller particles are called sediments. These sediments are transported, compressed and hardened to form layers of rocks. These types of rocks are called sedimentary rock.
Igneous and sedimentary rocks can change into metamorphic rocks under great heat and pressure. The process of transformation of the rock from one to another is called the rock cycle.
Rocks are made of different minerals. Minerals are naturally occurring substances which have certain physical properties and definite chemical composition.
The earth is constantly undergoing changes inside and outside. Therefore, it is called a dynamic planet.
The earth is made up of several concentric layers. The uppermost layer over the earth is the surface is called the crust. It is the thinnest of all the layers.
The mantle is just beneath the crust.
The innermost layer is the core with a radius of about 3500 km.
The central core has a very high temperature and pressure.
The earth’s crust is made up of several types of rocks.
There are three types of rocks—igneous rocks, sedimentary rocks and metamorphic rocks.
Igneous rocks are also called primary rocks. They are of two types—intrusive rocks and extrusive rocks.
Extrusive igneous rocks have a very fine-grained structure. For example, basalt.
Intrusive igneous rocks are formed deep inside the earth. Granite is an example of this rock.
Sedimentary rocks are formed by the sediments, which are small fragments of rocks. For example, sandstone is made from grains of sand.
Igneous and sedimentary rocks can change into metamorphic rocks under great heat and pressure. For example, clay changes into slate and limestone into marble.
Hard rocks are used for making roads, houses and buildings.
One type of rock changes to another type under certain conditions in a cyclic manner. This process of transformation of the rock from one to another is known as the rock cycle.
Rocks are made up of various minerals.
Minerals are naturally occurring substances which have certain physical properties and definite chemical composition. Minerals are very essential for human beings.
Crust: The uppermost layer over the earth’s surface. It is very thin.
Soal: The continental mass of the crust consisting of silica and alumina is called sial (si-silica and al-alumina).
Sima: The oceanic crust mainly consists of silica and magnesium. It is therefore called sima (si-silica and ma-magnesium).
Mantle: This layer is just beneath the crust. It extends up to a depth of 2900 km. below the crust.
Rock: A rock is a natural mass of mineral matter that makes up the earth’s crust.
Igneous rock: These rocks are formed by cooling and solidifying molten magma.
Lava: It is fiery red molten magma coming out from the interior of the earth on its surface.
Extrusive igneous rock: When the molten lava comes on the earth’s surface, it rapidly cools down and becomes solid. Rocks formed in this way on the crust are called extrusive igneous rocks.
Intrusive igneous rock: When the molten magma cools down deep inside the earth’s crust solid intrusive igneous rocks are formed.
Sediments: These are small fragments of rocks.
Sedimentary rock: When loose sediments are compressed and hardened, layers of rocks are formed. These types of rocks are known as sedimentary rocks.
Rock cycle: The process of transformation of the rock from one to another is known as the rock cycle.
Mineral: Minerals are naturally occurring substances which have certain physical properties and definite chemical composition.
Environment Nature, place, people, things, etc. that surround the living organisms make the environment. The environment can broadly be classified into the natural and human environment. It is a combination of both natural as well as man-made phenomena.
The natural environment comprises biotic (plants and animals) and abiotic-conditions(land, water, air, etc.), whereas the man-made phenomena comprise the activities and interactions among human beings (roads, bridges, etc.).
Natural Environment
Land, water, air, plants and animals comprise the natural environment.
Lithosphere, atmosphere, hydrosphere and biosphere are the four domains of the natural environment.
The lithosphere is the solid crust or the outermost layer of the earth where we live. It contains landforms like mountains, plateaus, plains and valleys.
The hydrosphere is the domain of water. It comprises water bodies like rivers, lakes, seas, oceans, etc.
The atmosphere is the thin layer of air that surrounds the earth. It protects us from the harmful rays and scorching heat of the sun.
The biosphere is a narrow zone of the earth where land, water and air interact with each other to support life.
What is Ecosystem?
The relation between the living organisms as well as the relation between the organisms and their surrounding form the ecosystem.
There could be an ecosystem of large rainforest, grassland, desert, mountains, lake, river, ocean and even a small pond.
Human Environment
Human beings interact with the environment and modify it according to their needs.
Early humans adapted themselves to their natural surroundings.
With time, humans learnt to grow new things, domesticate animals and lead a settled life.
The industrial revolution, transportation and information revolution made communication easier and speedy across the world.
Man is destroying the environment through deforestation, industrialisation, etc.
The environment in our basic life support system. It provides the air we breathe, the water we drink, the food we eat and the place where we live. Thus, the environment is the most important aspect of our life.
The natural environment consists of land, water, air, plants and animals. It refers to both biotic and abiotic conditions existing on the earth.
While biotic refers to the world of living organisms, such as plants and animals, abiotic refers to the world of non-living elements, such as land.
The human environment refers to the activities, creations and interactions among human beings.
Domains of environment—Lithosphere, hydrosphere, atmosphere and biosphere.
The lithosphere is the solid portion of the earth where we live. It is the domain that provides us forests, grasslands for grazing, land for agriculture and human settlements. It is where we find several minerals.
Hydrosphere refers to the water bodies like rivers, lakes, seas, oceans, etc. that exist on the earth.
The atmosphere is the thin layer of air that surrounds the earth. It protects us from the harmful rays and searching heat of the Sun. It consists of gases, dust and water vapour.
Biosphere or the living world is comprised of plant and animal life. It is a narrow zone of the earth where land, water and air interact with each other to support life.
The relation between the living organisms as well as the relation between the organisms and their surroundings form an ecosystem.
An ecosystem can be found in lakes, mountains, oceans, pond, etc.
Human beings modify the natural environment as per their needs.
Environment: The place, people, things and nature that surround any living organism is called the environment.
Biotic: It refers to the world of living organisms, such as plants and animals.
Notes of Chapter 10 Eighteenth-Century Political Formations Class 7th History
The Crisis of the Empire and the Later Mughals
• By the end of the seventeenth century, Mughal Empire was shrinking. There are various factors behind this:
→ Emperor Aurangzeb had depleted the military and financial resources of his empire by fighting a long war in the Deccan.
→ Under his successors, the efficiency of the imperial administration broke down.
→ Peasant and zamindari rebellions in many parts of northern and western India.
→ In the midst of this economic and political crisis, the ruler of Iran, Nadir Shah, sacked and plundered the city of Delhi in 1739 and took away immense amounts of wealth.
→ The empire was further weakened by competition amongst different groups of nobles. They were divided into two major groups or factions, the Iranis and Turanis.
Emergence of New States
• Through the eighteenth century, the Mughal Empire gradually divided into a number of independent, regional states.
• Broadly these independent states can be divided into three groups:
→ States that were old Mughal provinces like Awadh, Bengal and Hyderabad.
→ States that had enjoyed considerable independence under the Mughals as watan jagirs. These included several Rajput principalities.
→ States under the control of Marathas, Sikhs and others like the Jats. These had seized their independence from the Mughals after a long-drawn armed struggle.
The Old Mughal Provinces
Hyderabad
• Founded by: Nizam-ul-Mulk Asaf Jah (1724-1748) was powerful member at the court of the Mughal Emperor Farrukh Siyar.
• Asaf Jah brought skilled soldiers and administrators from northern India.
• He appointed mansabdars and granted jagirs.
• The state of Hyderabad was constantly engaged in a struggle against the Marathas to the west and with independent Telugu warrior chiefs (nayakas) of the plateau.
Awadh
• Founded by: Burhan-ul-Mulk Sa‘adat Khan.
• Awadh was a prosperous region, controlling the rich alluvial Ganga plain and the main trade route between north India and Bengal.
• Sa‘adat Khan tried to decrease Mughal influence in the Awadh region.
• He reduced the size of jagirs, and appointed his own loyal servants to vacant positions.
• The state sold the right to collect tax to the highest bidders called ijaradars.
Bengal
• Founded by: Murshid Quli Khan
• He very quickly seized all the power that went with formal subadar office.
• He commanded the revenue administration of the state.
• Revenue was collected in cash with great strictness from all zamindars.
• Under the rule of Alivardi Khan (r. 1740-1756), the banking house of Jagat Seth became extremely prosperous.
The Watan Jagirs of the Rajputs
• Many Rajput kings were permitted to enjoy considerable autonomy in their watan jagirs.
• In the eighteenth century, these rulers now attempted to extend their control over adjacent regions.
• Raja Ajit Singh of Jodhpur held the governorship of Gujarat and Sawai Raja Jai Singh of Amber was governor of Malwa.
• They tried to extend their territories by seizing portions of imperial territories neighbouring their watans.
• Maratha campaigns into Rajasthan from the 1740s checked their further expansion.
Seizing Independence
The Sikhs
• During the seventeenth century, Sikhs built regional state, Punjab.
• Several battles were fought by Guru Gobind Singh against the Rajput and Mughal rulers.
• After his death in 1708, the Khalsa rose in revolt against the Mughal authority under Banda Bahadur’s leadership. → Banda Bahadur was captured in 1715 and executed in 1716.
• The Sikh territories in the late eighteenth century extended from the Indus to the Jamuna but they were divided under different rulers.
• Maharaja Ranjit Singh, reunited these groups and established his capital at Lahore in 1799.
The Marathas
• Shivaji (1627-1680) carved out a stable Maratha kingdom with the support of powerful warrior families (deshmukhs).
• After Shivaji’s death, effective power in the Maratha state was exercises by a family of Chitpavan Brahmanas who served Shivaji’s successors as Peshwa (or principal minister).
• Between 1720 and 1761, the Maratha empire expanded.
• By the 1730s, the Maratha king was recognised as the overlord of the entire Deccan peninsula.
• The Marathas developed an effective administrative system as well.
• New trade routes emerged within the areas controlled by the Marathas.
The Jats
• The Jats consolidated their power during the late seventeenth and eighteenth-centuries.
• Under their leader, Churaman, they acquired control over territories situated to the west of the city of Delhi.
• The Jats were prosperous agriculturists.
• The important trading centres in the areas under Jats were Panipat and Ballabgarh.
The Making of Regional Cultures Class 7 Notes Social Science History Chapter 9
The medieval period saw the emergence of several regional languages and the associated literature. It is quite common for us to identify a region with its language.
Every region is identified with a certain distinct type of food, clothing, poetry, dance, painting and music.
The Chera empire of Mahodayapuram, which was established in 9th century in the southwestern part of Kerala introduced the Malayalam language.
Rulers and Religious Traditions: The Jagannatha Cult
In several regions, regional cultures developed around religious traditions.
The local people made a wooden image of the deity which, originally a local God, came to be identified with Vishnu.
Temple became the centre of pilgrimage.
The Rajputs and Traditions of Heroism
In the 19th century, the Rajasthan of today was called Rajputana by the British.
There are many groups who call themselves Rajputs in Northern and Central India.
Prithviraj Chauhan was one such ruler.
Women had been given a heroic image since they committed sati or self-immolation.
Beyond Regional Frontiers: The Story of Kathak
The heroic traditions of various regions also helped in the evolution of dance in several regions.
One such dance was Kathak, which was evolved in Northern India. The Kathaks initially were a caste of story-tellers in North Indian temples.
The legends of Radha-Krishna were enacted in folk plays known as rasalila.
It integrated folk dance with the basic gestures of the kathak story-tellers.
Music also developed into various forms like qawwali and khayal and new instruments like Sitar were invented.
Paintings for Patrons: The Traditions of Miniatures
During this period, one more tradition which deserves our attention is the miniature painting. Miniatures are small sized paintings done in watercolour on cloth or paper.
Akbar, Jahangir and Shah Jahan hired highly skilled painters to illustrate their manuscripts in the Kitab Khana containing their accounts and poetry.
When the Mughal empire started declining, new artistic tastes developed in the regional court of Deccan and Rajput rulers.
One bold style of miniature painting was called Basohli.
One of the most popular paintings of the Himalayas region was Bhanudatta’s Rasamanjari.
The Kangra artists by mid-18th century infused a new life into miniature painting.
The Growth of a Regional Language: Bengal
Regional language is the language which a person speaks in a region.
It is generally assumed that the Bengali language is spoken by people of Bengal.
Bengali originated from Sanskrit but later on developed its own identity and literature.
Early Bengali literature may be divided into two categories—The first includes translations from Sanskrit epics and the
the second includes Nath literature.
Pirs and Temples
From the 16th century, people migrated in large numbers from less fertile western Bengal to the forested and marshy of south-eastern Bengal.
With Mughal control over Bengal, the capital shifted to Dhaka. Officials received land grants. Mosques were set up.
The early settlers got help from teachers called Pirs. They included saints or Sufis and prominent religious personalities.
Regional cultures today are often the product of complex processes of intermixing of local traditions with ideas from other parts of the subcontinent.
The Chera Kingdom of Mahodayapuram was established in the ninth century in the south-western part of the peninsula, part of present-day Kerala. The rulers introduced the Malayalam language and script in their inscriptions.
The Cheras also drew upon Sanskritic traditions. The temple theatre of Kerala borrowed stories from the Sanskrit epics.
In other regions, regional cultures grew around religious traditions. The best example of this process is the cult of Jagannath at Puri, Orissa. The word Jagannath literarily means the lord of the world, a name for Vishnu.
Anantavarman, the ruler of the Ganga dynasty in the 12th century, built a temple for Purushottama Jagannatha at Puri.
The Rajputs contributed a lot to the distinctive culture of Rajasthan. From about the eighth century, most of the present-day state of Rajasthan was ruled by various Rajput families. Prithviraj was one such ruler.
Rajput rulers cherished the ideal of the hero who fought valiantly, often choosing death on the battlefield rather than face defeat.
Stories about Rajput heroes were recorded in poems and songs. Women were also focused on these stories. They are depicted as following their heroic husbands in both life and death. They often chose to become sati on the funeral pyre of their husbands.
Not only heroic traditions are found in different regions in different forms, but dance too. Just take the history of one dance form, Kathak.
The term kathak is derived from Katha, a word used in Sanskrit and other languages for a story.
The Kathaks was originally a caste of story-tellers in temples of north India, who beautified their performances with gestures and songs.
Kathak began evolving into a distinct mode of dance in the 15th and 16th centuries.
Under the Mughals, it developed in two traditions or gharanas—one in the courts of Rajasthan (Jaipur) and the other in Lucknow. Slowly and steadily it took root in Punjab, Haryana, Jammu and Kashmir etc.
Kathak was recognised as one of six classical forms of dance in the country after independence. Other classical dances are—Bharatnatyam (Tamil Nadu), Kathakali (Kerala), Odissi (Orissa), Kuchipudi (Andhra Pradesh) and Manipuri (Manipur).
The tradition of miniature painting is also noteworthy. Miniatures are small-sized paintings, generally done in watercolour on cloth or paper. The earliest miniatures were on palm leaves or wood.
The Mughal emperors patronised highly skilled painters.
With the decline of the Mughal Empire, many painters moved out to the courts of the emerging regional states.
By the late 17th century a bold and intense style of miniature painting called Basohli got developed in the Himalayan foothills around the modern-day state of Himachal Pradesh. Here, the Mughal artists founded the Kangra school of painting.
Soft colours, including cool blues and greens, and lyrical treatment of themes distinguished Kangra painting.
Now we will see how Bengali, a regional language, grew in the course of time.
From the eighth century, Bengal became the centre of a regional kingdom under the Palas. Between the 14th and 16th centuries, Bengal was ruled by Sultans. In 1586, Akbar conquered Bengal while Persian was the language of administration, Bengali developed as a regional language.
Early Bengali literature may be divided into two categories. The fist includes translations of the Sanskrit epics, the Mangala Kavyas and Bhakti literature such as biographies of Chaitanyadeva, the second includes Nath literature such as songs of Maynamati and Gopichand, stories concerning the worship of Dharma Thakur and fairy tales, folk tales and ballads.
The cult of ptr (a spiritual guide) became popular in Bengal and their shrines can be found there.
A number of temples got constructed in Bengal. Now local deities began to be worshipped in temples.
Bengal, being in a riverine plain, produces abundant rice and fish. These two items are important foods of the Bengalis. The Bengal Brahmanas too eat fish.
Fishing has been a major occupation of the Bengalis.
Bengali literature contains several references to fish.
Lilatilakam: A fourteenth-century text of Sanskrit that deals with grammar and poetics.
Rajputana: The region that constitutes most of present-day Rajasthan was called Rajputana by the British during the 19th century.
Sati: The immolation of widows on the funeral pyre of their husbands.
Kathak: The term is derived from Katha, a word used in Sanskrit and other languages for the story.
Rasa Lila: The legends of Radha-Krishna were enacted in folk plays known as rasa Lila.
Gharana: Tradition of classical dance, music.
Classical: Old and memorable having permanent value.
