Question

Consider the following statements (1 - 2) related to revolution and rotation of the planets and select the correct option.

Statement 1: The rotation of planet Earth causes daily or diurnal rhythm of plant and animal life.
Statement 2: Tilt of the planet Earth's axis causes different seasons.

• A. Both statements 1 and 2 are correct
• B. Only statement 2 is correct
• C. Both statements 1 and 2 are incorrect
• D. Only statement 1 is correct

Answer 1

The correct option is A Both statements 1 and 2 are correct

Different parts of Earth experience different seasons because of the Earth's rotation and revolution on an imaginary axis that is tilted at an angle of about 23.5 degrees.

The rotation of Earth on its axis defines day and night cycles. Revolution of Earth around the Sun in a slightly tilted manner causes the occurrence of different seasons, as the amount of light reaching different parts of the Earth at different times of the year varies.

Earth rotates counter-clockwise and due to this different parts of the Earth are either facing towards the Sun or moving away from it. It takes 24 hours for the world to turn around and reach the same point, and that makes a day. Due to this periodic movement a daily or diurnal rhythm is created in plant and animal life. Hence statement I is correct.

Figure : Rotation of Earth

Animals use the day-night cycle and seasonal variations in light intensity as a means for planning their foraging time (searching for food resources), reproduction (giving rise to younger ones) and migration (movement of animals on a seasonal basis in search for shelter, food). While it affects photosynthesis and flowering in plants.

While revolving in a tilted axis, the Earth also changes distance from the Sun. Due to this some part is closer to the Sun and receives direct sunlight while other part is away from Sun and receives less light. Because of this, each part of Earth experiences different climates and accordingly different seasons. These different climates lead to different kinds of flora (plants) and fauna (animals) which adapt to those climates. Hence statement II is correct.

Figure : Availability of sunlight

Figure : Revolution of Earth around the Sun in a slightly tilted axis results in different seasons