The Realms of the Earth Part-4( Class 6th D.A.V)
131This video is about the Realms of the Earth Hydrosphere and Biosphere and importance of hydrosphere.
Hydroshpere;- the layer of water on and below the surface of the Earth. Water covers about 2/3rd of the surfacew of the Earth. Therefore Earth is also known as watery planet or Blue planet. The largest part of the Earth is covered by oceans. Water is present in the form of ice sheets in polar regions and in mountians, lakes and rivers. Oceans :- There are five oceans:- Pacific, Atlantic, Indian, SOuthern and Arctic.
Pacific ocean:- This is the largest and deepest ocean. The average depth is near about 7300 metre.The ocean is surroiunded by four continents- North America, South America, Asia and Antarctica.
Atlantic ocean:- It is about half of the size of the pacific ocean. It covers 1/6 of the total surface of the Earth. It has two developed continents on two sides. Europe in the Eastand North America in the west.
Indian ocean:- Smaller than pacific and Atlantic. It is bounded by continents Asia, Africa and Australia. It is only the ocean named after the country India.
Arctic ocean:- This ocean lies within the Arctic circle and North pole in the centre. It is the smallest ocean. The pacific and Atlantic ocean merge into the north. Asia, Europe and North America make the Northern Boundaries. It remains frozen for the larger part of the year.
Southern ocean:- This ocean is around the Antarctica. It remains frozen four months of the year.
Importance of hydroshpere:- It brings rain, Regulates temperature of the environment, generates electricity, Serve as the means of transport, used for domestic purpose, Habitat of numerous aquatic plants and animals.
Biosphere:- The sphere of life comprises of all forms of organisms. The basic component of the Earth. Lithosphere, Hydrosphere and atmosphere jointl help to create biosphere. Life exist only nine kilometre above the Earth and 11 km below the ocean surface. It is a sphere where four non living elements land, water, air and sunlight are present.
There are variety of life forms in different parts due to variety of climate and physical condtion on the Earth varying from place to place.
Human activities responsible for cacusing ecological imbalance.
Human activitites like deforestation, urbanistaion, industrialisation
It causes several problems like :- Global warming, flood, pollution, landslides, soil erosion, increase the level of CO2 etc.