GEO (VI)-LESSON-2 OCEANS AND CONTINENTS (LESSON NOTES)

 

                                                        GEO (VI)-LESSON-2

OCEANS AND CONTINENTS

(LESSON NOTES)

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v INTRODUCTION  

Ø   The ocean is the vast reservoir of Nature. The globe began with the ocean, so to speak, and who knows if it will not end with it. The oceans cover almost seven tenth of territorial globe. In this lesson we try to know about:

§  What are oceans and continents? What are their names and their distribution?

§   In what ways do oceans and continents impact life on Earth, including human life?

v EARTH SURFACE

  Ø The earth surface is covered many by two colors blue and brown that represent water and land part. They are:-

§  BROWN COLOUR- The large body of land is called a ‘landmasses, and a large continuous expanse of land is called a ‘continent. Brown colour is represented the land part on the Globe. It cover one forth part of the earth.

§  BLUE COLOUR- The largest water bodies we see on the globe are called ‘oceans’. They are represented by blue colour. These covers nearly three fourth part of the Earth.

Ø 

v The Distribution of Water and Land on the Earth

  Ø Oceans and continents are not distributed equally between the Northern and Southern Hemispheres.

  Ø Oceans are interconnected.

  Ø In northern hemisphere land part is more compare the water bodies.

  Ø In southern hemisphere water bodies are more.

 

v DIFFERENCE BETWEEN SALTY WATER AND FRESH WATER

 

SALTY WATER	FRESH WATER
1. Ocean water is salty water which comprise almost 3/4 part of the earth.	1.    Freshwater makes up a very small proportion of the planet’s water resources
2.    Seawater is salty and unfit for consumption.	2.It is fit for consumption.
3.    It is found in the oceans.	3.it is found in glaciers, rivers, lakes, in the atmosphere and also underground.

v OCEANS

Ø More than 71 % per cent of the Earth is covered with water, therefore, the Earth is called the blue planet.

§  More than 97% of the Earth’s water is found in the oceans. There are five major oceans in the world. They are interconnected.

§  THE PACIFIC OCEAN: - Largest Ocean

§  THE ATLANTIC OCEAN: -

§  THE INDIAN OCEAN: -

§  SOUTHERN OCEAN: -

§  THE ARCTIC OCEAN: -

  Ø There are other smaller extension of water bodies also as :-

·      Sea

·      Bay

·      Gulf

v OCEAN LIFE (MARINE LIFE)

   Ø Oceans consist a rich diversity of plans and animals that known as marine life. In includes as

  Ø Flora (Plants): - The marine flora includes tiny plants called algae and all kinds of seaweeds.

  Ø Fauna (Animals): - The marine fauna consists of thousands of species of colourful fish, dolphins, whales, and countless mysterious deep-sea creatures.

v  OCEANS AND DISASTERS: -

  Ø White colour around the Earth represents the clouds which takes water from the oceans and bring rain in the continents. There are many disasters associated with the oceans as: -

§  Extreme Rainfall

§  Cyclones: -

§  Tsunami

·      It is a huge and powerful wave generally caused by a strong earthquake or a volcanic eruption at the bottom of the ocean.

·      Tsunamis can travel thousands of kilometres and submerge coastal areas, causing widespread damage.

·      On 26 December 2004, India and another 13 countries around the Indian Ocean were struck by a powerful tsunami caused by an earthquake in Indonesia.

  Ø Events that lead to loss of life and property are handled under disaster management. India has its own ‘National Disaster Management Authority’ to deal with all kinds of disasters

v Continents

§  The large landmasses are known as the continents.

§  We may list any number of continents between four and seven.

§  In practice, the last list of seven continents is the one most widely adopted and used.

§  The greater part of the land mass lies in the Northern Hemisphere.

Count of continents (in alphabetical order)
Four continents	Africa-Eurasia, America, Antarctica, Australia
Five continents	Africa, America, Antarctica, Australia, Eurasia
Six continents	Africa, Antarctica, Australia, Eurasia, North America, South America
Seven continents	Africa, Antarctica, Asia, Australia, Europe, North America, South America

v ISLANDS

Ø Smaller pieces of land are left out; surrounded by water on all sides, they are called islands.

Ø Continents are also surrounded by water, but they are not considered islands because they are so large.

Ø There are lakhs of islands on the planet, of very different sizes.

Ø Greenland is the largest island in the world (locate it on a globe or a map)

Ø India has more than 1,300 small islands! Those include two major groups

§  Andaman and Nicobar Islands in the Bay of Bengal

§  Lakshadweep Islands in the Arabian Sea

Ø In 1983, India established its first scientific base station there, called ‘Dakshin Gangotri’ (two more bases were established later- Maitri and Bharati)

 

v OCEANS AND LIFE

Ø Oceans play a crucial role in regulating the climate and sustaining life on Earth: -

§  Oceans send rain to the continents; this is part of the Earth’s water cycle.

§  More than half of the world’s oxygen is produced by the oceans’ flora, which is why they are called ‘the planet’s lungs’.

§  From the ancient time people have used oceans and seas to migrate to other regions, to trade in all kinds of goods, to conduct military campaigns, and as a source of food through fishing.

§  Oceans have also nourished the cultures of coastal people all over the world. Almost all of them have tales and legends about the sea, sea gods and goddesses, sea monsters and treasures.

§  June 8 declared as  World Oceans Day by UNO