The earth is the third planet from the sun and the fifth-largest planet in the solar system
Earth is the onlyplanet which supports life
70 per cent of the earth's total area is covered by water
The family of the sun is called the Solar System
Members of the solar system
Planets
Satellites
Asteroids
Comets
Meteorites
The planets in order of their distance from the sun are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune
Shape of the Earth
Bulges slightly at the centre
Flattened at the poles
In the olden days, the earth was considered to be a flat disc with steep edges
Aryabhatta, the 5th century Indian astronomer and mathematician, believed in the round shape of the earth
Pythagoras, the 6th century Greek philosopher, said the earth was spherical in shape
Today, we have convincing evidence to prove that the earth is spherical in shape
Proof that the Earth is Spherical in shape
Sighting of a ship
Bedford Level Experiment
Pole Star
Satellite Pictures
Lunar Eclipse
Circular Horizon
Sunrise and Sunset
Circumnavigation
The earth is said to be an Oblate Spheroid, which means it bulges at the equator and is flattened at the poles
The earth belongs to the Solar system and all planets in this system are spherical in shape
Features that make Earth habitable
Distance from the Sun
Temperature
Atmosphere
Water
The earth is at an optimumdistance from the sun, which makes life possible
The earth has an average temperature of 17°C which is suitable for life to exist
The earth's atmosphere is a mixture of gases like nitrogen, oxygen, carbon dioxide, helium and argon
Ozone in the earth's atmosphere absorbs the harmful ultraviolet rays of the sun
The earth's atmosphere prevents loss of heat from the earth's surface and helps to keep the earth warm
70percent of the earth's surface is covered by water
Water cycle
1. Evaporation from oceans
2. Transpiration from plants
3. Condensation
4. Precipitation
The self-regulating and self-sustainingstructural and functionalunit of the biosphere is called the Ecosystem
The ecosystem depends upon the sun for its energy
The atmosphere receives heat from the sun by solarradiation and loses heat by earth'sradiation. In this way a balance is maintained
Gases in the earth's atmosphere
Nitrogen
Oxygen
Carbondioxide
Helium
Argon
Ozone present in the earth's atmosphere absorbs the harmfulultravioletrays of the sun
The atmosphere also prevents loss of heat from the earth's surface and helps to keep the earth warm
Earth is a watery planet with 70 per cent of the earth's surface being covered by water
Ecosystem
The self-regulating and self-sustaining structural and functional unit of the biosphere
Examples of ecosystems
Pond
Lake
Desert
Grassland
Meadow
Forests
There is an exchange of materials and energy within the ecosystem as well as between adjoining ecosystems. They are all interconnected and hence, interrelated
Biosphere
The part of the earth's terrestrial system-including air, land and water-in which life develops and where life processes in turn get transformed
Water can absorb enormous amount of heat without causing much change in its temperature
But for the tremendous amount of water on the earth, far greater day and night temperature variations would exist
Lithosphere
The solidcrust of the earth
Due to the weathering of the rocks, the surface of the earth has been formed, which provides soillayeressential for supporting plant life
Soil also provides various nutrients necessary for the growth of plants, which in turn support all forms of animal life directly or indirectly
Biosphere
The narrowrealm of contact and interaction between the atmosphere, lithosphere and hydrosphere
Biosphere provides all the necessities for all the species living on earth, i.e., light, heat, water, food and habitats