General Studies

 

Origin time of the major plant and animal groups( Approximate)

 

Organism Group-  Time of Origin

 

Land Plants -438 Million Years Ago

Marine Invertebrates-570 Million Years Ago

Fish – 505 Million Years Ago

Reptiles -320 Million Years Ago

Amphibians -408 Million Years Ago

Flowering Plants (Angiosperms) -140 Million Years Ago

Mammals -208 Million Years Ago

Earth: Fact Points

 

The Earth is the largest of the inner planets of the Solar System.

It is the third closest planet to the Sun.

Earth is the sole home of human life in the entire Solar System.

It is the fifth largest planet which is at a distance of 149,597,900 km from the Sun.

The shape of the Earth approximates an oblate spheroid, a sphere flattened along the axis from pole to pole such that there is a bulge
around the equator.

Earth’s Axis

It is an imaginary line that runs right across and passes through the centre of the Earth.

The Earth spins round its axis which always remains inclined at an angle of 66.50 to the plane of the Earth’s orbit.

Orbit

It is the elliptical path of the Earth’s revolution round the Sun.