Origin of Earth
Origin of Earth and Evoluation of the Environment
MODULE - 1
Environment through Ages
1
ORIGIN OF EARTH AND EVOLUTION OF THE ENVIRONMENT
We live on a beautiful planet called earth, along with a wide variety of plants, animals and other organisms. Our earth, however, is part of a vast universe. The universe is about 15 to 20 billion years old. The age of the earth is approximately 4 to 5 billion years, while human beings evolved only around 2 million years ago. In this lesson, you shall learn how the earth originated, how it got its own environment and in what ways human beings have been using the environmental resources for their welfare and development.
Notes
OBJECTIVES
After completing this lesson, you will be able to: • • • • • trace the origin of the earth; list the conditions, which make the earth a unique planet for supporting life; describe the sequence of steps in the origin and evolution of life prior to the appearance of humans; explain the term environment; enumerate the various biotic and abiotic constituents of the environment.
1.1 EARTH AS PART OF THE UNIVERSE AND THE SOLAR SYSTEM
Our earth, with all its diversity alongwith other planets and their satellites, the sun, the moon, the many galaxies (huge groups of millions of stars) form the universe. There are also countless asteroids and comets in orbit around the sun. All these are also part of the universe. It extends much farther than can be seen by the most powerful telescope. No one knows where the universe ends.
1
MODULE - 1
Environment through Ages
Environmental Science Senior Secondary Course When you look up at the sky on a clear night, you see many points of light – most of which are stars. Stars are huge balls of bright, hot glowing gases. The ‘Sun’ is also a star. It is the star nearest to earth – about 150 mk (million kilometers) away. A solar system consists of a star in the middle with a number of planets orbiting around it. The earth is a part of its solar
MODULE - 1
Environment through Ages
1
ORIGIN OF EARTH AND EVOLUTION OF THE ENVIRONMENT
We live on a beautiful planet called earth, along with a wide variety of plants, animals and other organisms. Our earth, however, is part of a vast universe. The universe is about 15 to 20 billion years old. The age of the earth is approximately 4 to 5 billion years, while human beings evolved only around 2 million years ago. In this lesson, you shall learn how the earth originated, how it got its own environment and in what ways human beings have been using the environmental resources for their welfare and development.
Notes
OBJECTIVES
After completing this lesson, you will be able to: • • • • • trace the origin of the earth; list the conditions, which make the earth a unique planet for supporting life; describe the sequence of steps in the origin and evolution of life prior to the appearance of humans; explain the term environment; enumerate the various biotic and abiotic constituents of the environment.
1.1 EARTH AS PART OF THE UNIVERSE AND THE SOLAR SYSTEM
Our earth, with all its diversity alongwith other planets and their satellites, the sun, the moon, the many galaxies (huge groups of millions of stars) form the universe. There are also countless asteroids and comets in orbit around the sun. All these are also part of the universe. It extends much farther than can be seen by the most powerful telescope. No one knows where the universe ends.
1
MODULE - 1
Environment through Ages
Environmental Science Senior Secondary Course When you look up at the sky on a clear night, you see many points of light – most of which are stars. Stars are huge balls of bright, hot glowing gases. The ‘Sun’ is also a star. It is the star nearest to earth – about 150 mk (million kilometers) away. A solar system consists of a star in the middle with a number of planets orbiting around it. The earth is a part of its solar