,Content
Module 1: Environment through Ages
Origin of Earth and Evolution of the Environment
Environment and Human Society
Degradation of Natural Environment
Module 2: Ecological Concepts and Issues
Principles of Ecology
Ecosystem
Natural Ecosystem
Human Modified Ecosystems
Module 3: Human Impact on Environment
Human societies
Deforestation
Module 4: Contemporary Environment Issues
Environmental Pollution
Environment and Health
Disasters and their Management
National Environmental Issues
Global Environmental Issues
Module 5 - Environmental Conversation
Biodiversity Conversation
Conservation of other Natural Resources
Conservation of Soil and Land
Water and Energy Conservation
Module 6: Sustainable Development
Origin and concept of Sustainable Development
Modern Agriculture
Concept of Sustainable Agriculture
Clearner Technology
Module 7 - Environmental Management
Environmental Legislation
Environmental Impact assesment
Environmental Related Institutions and Organisations
Environmental Ethics and Gandhian Approach
Module 8A - Water Resource Management
Global Circulation of Water
Ground water Resources
Fresh water Resources
Methods of water Harvesting
Water Conservation at Different Levels
Module 8B - Energy and Environment
Importance of Energy in society
Non-Renewable Sources of energy
Renewable Sources of energy - I
Renewable Sources of energy - II
Energy Conservation
,Origin of Earth and Evoluation of the Environment MODULE - 1
Environment through
Ages
1 Notes
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.
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 Environmental Science Senior Secondary Course
Environment through
Ages
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 system. It is one of the eight planets of the solar system that has the sun (a star) in the
Notes middle and the eight planets moving around it. Until recently solar system was believed to
have nine planets. However, on the basis of the latest scientific assessment, Pluto, is no
longer regarded as a planet of earth’s solar system. (Fig. 1.1)
Sun
Fig. 1.1: Planets orbiting the sun
1.2 ORIGIN OF THE UNIVERSE AND ORIGIN OF THE
EARTH
The widely accepted theory of the origin of universe is the “BIG BANG” theory. According
to this theory, universe started with a huge explosion and matter (dust and gases) filled the
entire space. The temperature of the universe then, was about hundred billion degrees
Celsius. Scientists believe that the big bang occurred about 15 to 20 billion years ago. The
huge collection of dust and gases then began to spin. As it spun faster and faster, the centre
became very hot. It became the Sun. From the edges of this ball of dust and gas, big blobs
or chunks of dust broke off and formed eight ball shaped planets. This founded our solar
system (Fig. 1.2). The earth broke off about 4.5 billion years ago with an explosion. It was
a burning hot white mass of gas and dust. Over a long period of time, dust and gas gradually
condensed to form solid rock. Such condensation and shrinking made the earth heat up so
much that the rock melted into a gluey liquid. After millions of years, the outer surface of
the earth or the earth’s crust cooled and formed hard rock again, just as melted chocolate
or wax solidifies upon cooling. The interior of the earth is still very hot.
2
Module 1: Environment through Ages
Origin of Earth and Evolution of the Environment
Environment and Human Society
Degradation of Natural Environment
Module 2: Ecological Concepts and Issues
Principles of Ecology
Ecosystem
Natural Ecosystem
Human Modified Ecosystems
Module 3: Human Impact on Environment
Human societies
Deforestation
Module 4: Contemporary Environment Issues
Environmental Pollution
Environment and Health
Disasters and their Management
National Environmental Issues
Global Environmental Issues
Module 5 - Environmental Conversation
Biodiversity Conversation
Conservation of other Natural Resources
Conservation of Soil and Land
Water and Energy Conservation
Module 6: Sustainable Development
Origin and concept of Sustainable Development
Modern Agriculture
Concept of Sustainable Agriculture
Clearner Technology
Module 7 - Environmental Management
Environmental Legislation
Environmental Impact assesment
Environmental Related Institutions and Organisations
Environmental Ethics and Gandhian Approach
Module 8A - Water Resource Management
Global Circulation of Water
Ground water Resources
Fresh water Resources
Methods of water Harvesting
Water Conservation at Different Levels
Module 8B - Energy and Environment
Importance of Energy in society
Non-Renewable Sources of energy
Renewable Sources of energy - I
Renewable Sources of energy - II
Energy Conservation
,Origin of Earth and Evoluation of the Environment MODULE - 1
Environment through
Ages
1 Notes
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.
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 Environmental Science Senior Secondary Course
Environment through
Ages
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 system. It is one of the eight planets of the solar system that has the sun (a star) in the
Notes middle and the eight planets moving around it. Until recently solar system was believed to
have nine planets. However, on the basis of the latest scientific assessment, Pluto, is no
longer regarded as a planet of earth’s solar system. (Fig. 1.1)
Sun
Fig. 1.1: Planets orbiting the sun
1.2 ORIGIN OF THE UNIVERSE AND ORIGIN OF THE
EARTH
The widely accepted theory of the origin of universe is the “BIG BANG” theory. According
to this theory, universe started with a huge explosion and matter (dust and gases) filled the
entire space. The temperature of the universe then, was about hundred billion degrees
Celsius. Scientists believe that the big bang occurred about 15 to 20 billion years ago. The
huge collection of dust and gases then began to spin. As it spun faster and faster, the centre
became very hot. It became the Sun. From the edges of this ball of dust and gas, big blobs
or chunks of dust broke off and formed eight ball shaped planets. This founded our solar
system (Fig. 1.2). The earth broke off about 4.5 billion years ago with an explosion. It was
a burning hot white mass of gas and dust. Over a long period of time, dust and gas gradually
condensed to form solid rock. Such condensation and shrinking made the earth heat up so
much that the rock melted into a gluey liquid. After millions of years, the outer surface of
the earth or the earth’s crust cooled and formed hard rock again, just as melted chocolate
or wax solidifies upon cooling. The interior of the earth is still very hot.
2
