Cbse class 6, Social Studies
MAJOR DOMAINS OF THE EARTH
- Life in Earth is possible because of land, water and air
- Environment is divided into Physical and biological environment
- Physical environment is made up of Land, air and water
- It is essential for existence of different life forms
- Biological environment is made up of Plants, animals
- It is essential for survival, and it provides food
- Our Environment consist of four realms. They are
- Lithosphere
- Hydrosphere
- Atmosphere
- Biosphere
Lithosphere
- Lithosphere is a solid surface of Earth, living things exist here
- Innermost and hottest layer of Earth is called as Core
- Layer of molten rock that surrounds core is called as Mantle
- Solid, rocky, uppermost part of Earth is Crust
- Crust and rigid upper layers of mantle together form Lithosphere
Two types of Lithosphere:
- Continental and Oceanic Lithosphere
- Lithosphere is made up of fragments called as Lithosphere Plates
- Lithosphere plate float on molten part of Mantle and often keep colliding
Importance of Lithosphere:
- Life exists in Lithosphere
- Lithosphere consist of rocks, minerals, precious stones, minerals and materials used in the production of energy
CONTINENTS:
Huge Landmasses on the Earth is called as Continents.
There are totally seven continents. They are
- Asia
- Africa
- Australia
- Antarctica
- North America
- South America
- Europe
ASIA:
- One third of Earth surface, the largest and most populous (populated ) continent is Asia
- Asia lies in Northern Hemisphere. Asia is located in East of Prime meridian and in Eastern hemisphere
Borders of Asia are:
- North – Arctic Ocean
- East – Pacific Ocean
- West – Europe
- South – Africa
- Tropic of cancer passes through Asia Continent
- Asia is separated from Europe by Ural Mountains, Black sea and Caspian sea
- Main Geographical feature in Asia is Ural Mountains, Europe
EUROPE:
- Europe is the sixth largest continent
- Peninsula is a narrow strip of land projecting into sea/lake from mainland
- Europe is a Peninsula with water bodies surrounding it on three sides
Europe is surrounded by
- North – Arctic Ocean
- West – Atlantic Ocean
- South – Mediterranean Sea and Africa
- Prime Meridian, Arctic circle passes through Europe
- Highest Mountain range in Europe is Alps
- Mount Blanc is the highest peak of Alps
AFRICA:
Africa is the second largest continent in the World
Africa is separated by
- Suez canal from Asia
- Strait of Gibraltar from Europe
- Equator passes through the Centre of Africa
- Africa lies partly in Northern and Southern Hemisphere
- Tropic of Cancer passes through Northern Africa
- Tropic of Capricorn passes through Southern Africa
- Sahara is the largest and hottest desert in Africa
NORTH AMERICA:
- North America is the Third largest continent
- North America lies in Northern Hemisphere
Borders of North America:
- East – Atlantic Ocean
- West – Pacific Ocean
- South – South America (Isthmus of Panama)
- 75% of North America is Canada, USA
- Rest is Greenland, Caribbean island (West Indies)
- Geographical feature of North America is Desert, Temperate forest, Taiga vegetation, grassland
SOUTH AMERICA:
- South America is fourth largest continent and fifth populated continent
- Most of the South America lies in Southern and in Western hemisphere
- Equator passes through the Northern most part of South America
Borders of South America is
- East – Atlantic Ocean
- West – Pacific Ocean
South America has largest mountain range Andes and World largest river Amazon
AUSTRALIA:
- Australia is smallest and island continent
- Australia lies in Southern hemisphere
- Australia located in South East Asia
- Australia is border by Indian Ocean and Pacific Ocean
- New Zealand, New Guinea and several other island altogether form the Australasia
- Australia has Rainforest, Desert, Savannah, Vegetation and Temperate forest
Geographical feature of Australia is
- Great dividing range
- Central lowland
- Western Desert
- Great Barrier reef
ANTARTICA:
- Fifth largest continent is Antarctica.
- It is also called as White and Frozen continent
- Antarctica is windiest, iciest, driest place on Earth
- Antarctica is surrounded by Pacific Ocean, Atlantic Ocean, Indian Ocean
- Research stations of various countries are set up in Antarctica for various studies
- India’s two research station in Antarctica are Maitri and Dakshin Gangotri
HYDROSPHERE
- Earth’s ocean, lakes, glaciers, water vapour and clouds comprise Hydrosphere
- Two third of Earth is covered with water in the form of Seas and Oceans
- Oceans are larger than seas
Five major oceans are
- Pacific Ocean
- Atlantic Ocean
- Indian Ocean
- Arctic Ocean
- Southern Ocean
World’s largest sea are
- South China Sea
- Caribbean Sea
- Mediterranean Sea
- Bering Sea
- Deepest and largest ocean of the world is Pacific Ocean
- Pacific Ocean bounded on
- West – Asia and Australia
- East – North and South America
- Pacific Ocean covers one third of Earth surface
- Ferdinand Magellan named Pacific Ocean meaning Calm or Tranquil
- International Date line passes through Pacific Ocean
- Deepest part of World Ocean is Mariana Trench is present in Pacific Ocean
- Second largest, S shaped Ocean is Atlantic Ocean
- Atlantic Ocean is busiest ocean for Trade and commerce
- Atlantic Ocean coastline is Intended provides good site for Sheltered harbour
What is Intended? What is the benefit for coastline indented?
- Intended means uneven edges/ surface with parts worn away
- When the coastline is intended, deep water come close to harbour and provide large entrance for ships
- Harboured sheltered in indented coast is protected from
- Strong winds
- Dangerous currents
- Only ocean named after a country is Indian Ocean
Indian Ocean bordered by
- West – Africa
- North – Asia
- East – Australia
- Smallest ocean in the world is Arctic Ocean
- Bering Strait connect Arctic Ocean with Pacific Ocean
- For most of the year, Arctic Ocean remains Frozen
- Southern Ocean encircles the continent of Antarctica
- Southern Ocean comprises Southern portion of Pacific, Atlantic, Indian Ocean
ATMOSPHERE
Surface of Earth is surrounded by a blanket of gases called Atmosphere
There are 5 distinct layers in the atmosphere
They are
- Troposphere
- Stratosphere
- Mesosphere
- Thermosphere
- Exosphere
Layers of atmosphere are result of Temperature changes, occurring in various altitudes
- Lowest layer of atmosphere is Troposphere
- Temperature in this layer decreases by 1 degree for every 165 Km elevation
- Clouds, lightening occur in Troposphere
- Atmospheres contain Ozone
- Ozone shield from UV radiation of the Sun
- Ozone helps to maintain even temperature
Ozone is a thin layer that helps to
- Allow warmth of sunrays to reach us
- Prevents internal heat from escaping Earth surface
- Atmosphere contain 21% oxygen which is essential for respiration
- Atmosphere contain 78% Nitrogen, source of Proteins for all living organism
- Carbon di oxide present in air used by green plants to make carbohydrates (Food)
- Water vapour present in air prevent from
- Body drying
- Act as a source of drinking water
- Near surface of Earth, atmosphere densest and air pressure is maximum
- When altitude increases, Density of air decreases
Temperature decreases
Air pressure decreases
BIOSPHERE
- The region between the surface and atmosphere of Earth is Biosphere
- Biosphere is occupied by living organism
- Vegetation and animal life varies in different part of Earth due to different climate
- The distinct zones of the biosphere each with its own climate, plant, animal life are called as Ecosystem
- Animals with thick fur found in cold regions
- Cactus plant grow in deserts
- Rice grows in tropical regions
- Reasons behind rapid loss of natural resources is
- Deforestation
- Converting agricultural land into industries and settlements
- Pollution
- 150 government leaders signed the convection of biological diversity in 1992 at Rio Earth submit
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