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Non-Rationalised Geography NCERT Notes, Solutions and Extra Q & A (Class 6th to 12th)
6th 7th 8th 9th 10th 11th 12th

Class 7th Chapters
1. Environment 2. Inside Our Earth 3. Our Changing Earth
4. Air 5. Water 6. Natural Vegetation And Wildlife
7. Human Environment–Settlement, Transport And Communication 8. Human Environment Interactions The Tropical And The Subtropical Region 9. Life In The Deserts



Chapter 1: Environment



Our environment is essentially our basic life-support system. It encompasses everything that surrounds us and influences our existence, from the air we breathe and the water we drink to the land we inhabit and the food we eat. The story of Ravi highlights a common modern experience: our environment is constantly changing, often due to human activities.

The term "environment" originates from the French word Environer, which means "neighbourhood." It is a combination of natural and human-made elements.

Components of Environment

The environment can be broadly classified into three main components:

A diagram showing the three main components of the environment: Natural (Air, Water, Land, Living Things), Human-Made (Buildings, Parks, Roads), and Human (Individual, Family, Community).


Natural Environment

The natural environment consists of the four major domains of the Earth: Lithosphere, Hydrosphere, Atmosphere, and Biosphere. These domains interact with each other to create the conditions necessary for life.

Lithosphere

The Lithosphere is the solid, outermost layer of the Earth, also known as the crust. It is composed of rocks and minerals and is covered by a thin layer of soil. Its surface is irregular and features a variety of landforms, including mountains, plateaus, plains, and valleys. This domain is vital as it provides us with forests, grasslands for animal grazing, land for agriculture and human settlements, and a rich source of mineral wealth.

Hydrosphere

The Hydrosphere represents the total amount of water on Earth. It comprises all sources of water, including rivers, lakes, seas, oceans, groundwater, ice caps, and glaciers. Water is absolutely essential for the survival of all living organisms, playing a critical role in regulating climate and supporting life processes.

Atmosphere

The Atmosphere is the thin envelope of air that surrounds our planet, held in place by Earth's gravitational force. It is a mixture of various gases (like nitrogen, oxygen, argon, and carbon dioxide), dust particles, and water vapour. The atmosphere is crucial for life as it:

Biosphere

The Biosphere is the part of the Earth where life exists. It is a relatively narrow zone where the lithosphere, hydrosphere, and atmosphere interact and overlap. This interaction creates the perfect conditions to support the vast diversity of life, from the smallest microbes to the largest whales. The biosphere is the global sum of all ecosystems, constituting the "living world."

A diagram illustrating the four domains of the environment: Lithosphere (land), Hydrosphere (water), Atmosphere (air), and Biosphere (the zone where they interact to support life).


What Is Ecosystem?

An ecosystem is a biological community of interacting organisms (biotic components) and their physical, non-living environment (abiotic components). The key feature of an ecosystem is the complex web of relationships through which energy and materials are transferred.

For example, in a forest ecosystem, plants produce energy from sunlight, soil, and water. Herbivores get energy by eating plants, and carnivores get energy by eating other animals. When these organisms die, decomposers like bacteria and fungi break them down, returning essential nutrients to the soil for plants to use again. This entire cycle of interaction and dependency forms the ecosystem.

Ecosystems can be of any size:

An illustration of a pond ecosystem showing the interaction between living organisms like fish, ducks, and plants, and non-living components like water, sunlight, and soil.


Human Environment

The human environment encompasses the world created by human beings through their activities, creations, and interactions. Humans are unique in their ability to not just adapt to the environment but to actively modify it to suit their growing needs.

Evolution of Human-Environment Interaction

  1. Early Humans: They lived in complete harmony with nature. They adapted themselves to their natural surroundings, fulfilling their basic needs directly from the environment without causing significant changes.
  2. Agricultural Revolution: Humans learned to grow crops, domesticate animals, and lead a settled life. This was the first major modification of the natural environment. The invention of the wheel led to better transportation and the production of surplus food.
  3. Trade and Commerce: Surplus food production led to the emergence of the barter system, a method of trade where goods are exchanged directly without the use of money. This was the beginning of trade and commerce.
  4. Industrial Revolution: This period saw the rise of factories and large-scale production, leading to major environmental changes, including pollution and resource depletion.
  5. Information and Transportation Revolutions: These revolutions have made communication and travel faster and easier across the globe, further increasing human impact on the planet.

The Need for a Perfect Balance

While human modifications have led to development and progress, they have also often disrupted the delicate balance of nature. The central challenge today is to achieve a harmonious way of life, where human needs are met without destroying the natural systems that support us. This requires sustainable practices and a deep respect for our environment.

A reminder of our planet's importance is World Environment Day, celebrated every year on June 5th, to raise awareness and encourage action for the protection of our environment.