Introduction.

Geography of Continents and Oceans.

Introduction.

Geography of the continents and the oceans studies continents, oceans, their geographical position, relief, climatic belts, natural zones, natural resources, peculiarities of vegetable and animal life, population, political map, inland waters. The greater part of the Earth’s surface is occupied by oceans, the smaller – by land. The total surface area of the Earth is 510 million sq km. The area of the land is 149 million sq km, which is only 29% (per cent) of the surface of the globe.

The oceans are linked and are really but one great ocean is called the World Ocean. There are five oceans on the globe: the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Arctic Ocean and the Southern Ocean. Large landmasses, surrounded by oceans and seas are called mainland or continents. There are 6 continents:

 

There are 6 continents.	There are 6 parts of the world.
Africa Australia Antarctica North America South America Eurasia	Africa Australia Antarctica America Europe Asia

 

The largest continent is Eurasia. The largest ocean is the Pacific Ocean. The warmest ocean is the Indian Ocean. The smallest and the coldest ocean is the Arctic Ocean.

We broadened our knowledge about the life in the World Ocean. While we are studding separate continents and oceans we knew when and by whom they were discovered, who explored them, what people live there, what states are situated on them now. We need deep geographical knowledge in order to stop the pollution of nature. Thanks to this knowledge we understand that we are responsible for our planet on which we live.

 

Maps

Maps are the important source of geographical knowledge. Using maps you may determine the disposition of the continents, oceans, rivers, states. All geographical maps are divided into 3 groups: a) by scale; b) by scope of the territory; c) by content

 

Geographical Maps

Are divided:

 

 

 

by scope of

the territory by scale

 

maps of the world and hemispheres

 

large scale maps

maps of the separate continents

 

medium scale maps

maps of the parts of the continent

 

small scale maps

topographical maps

 

 

 

by content

 

all geographical maps

 

 

special maps

 

 

complex maps

The Birth of Maps.

The first primitive drawings looking like maps appeared long before people learned to write. Archeologists still find them on the walls of the caves, mammoth tusks and wooden tables. The most ancient pictures of areas were made 10-15 thousand years ago. Cartography as a science appeared in ancient Greece. In the III century BC a famous mathematician and geographer Eratosthenes counted the length of the circumference of the Globe at the meridian. He made up the map of dry land known in those times and showed meridians and parallels on it. Another mathematician, astronomer and cartographer Claudius Ptolemy, who lived in Alexandria in the II century AD, made a book called “The Guide in Geography”. The book determined the development of cartography until the XV century.

Geographical Envelope.

Geographical envelope is the inner envelope of the Earth in which the interaction of the upper parts of the Lithosphere with lower parts of atmosphere, hydrosphere and biosphere takes place. All the parts of Geographical Envelope interact with each other.

Lithosphere.

Lithosphere is an outer layer of the earth crust 10 or 100 km deep, ¼ of whichforms land and ¾ - form oceanic bottom. It consists of 13 blocks, seven of which are very large (Pacific ocean plate, North American plate, South American plate, African plate, Eurasian plate, Indo-Australian plate, Antarctic plate). These blocks include the earth crust of the continents and oceans. Deep rifts separate the blocks from one another. In the places, where continental blocks come together, there are mountains. The blocks can move 1-6 sm a year. The movement of the blocks is connected with the movement of the mantle of the earth. Between the blocks of lithosphere there are active volcanoes and the earthquakes are frequent. These regions are called seismic belts. There are 3 layers in the Earth Crust:

- Sedimentary layer

- Granitic layer

- Basaltic layer

 

 

Atmosphere is the upper envelope of our planet. It is the mixture of gasses surround the Earth. The role of atmosphere is enormous.

 

Relief of the Earth.

Large territories of the dry land and oceanic cavities, vast plains and mountain ranges form an unusual surface of the Earth. Roughness of the Earth’s surface, which differs in size, origin and age is called therelief.

The largest forms of the relief on the Earth are continents and oceanic bottom. We distinguish two forms of relief on the continents: plains and mountains, and on the oceanic bottom – plains, mountains and oceanic cavities. The disposition of them depends on the peculiarities of the Earth Crust.

The Earth Crust consists of three layers (sedimentary, granitic and basaltic) on the continent and two layers (sedimentary and basaltic) on the oceanic bottom.

 

The Earth Crust consists of stable and unstable plots. The formation of the earth crust depends on outer and internal processes. Outer processes are: wind, waters, the sun, ice. Internal processes are: volcanoes, quakes.