Our Environment Chapter Notes | Window on the Word Class 7: Solutions, Notes & Worksheets PDF Download

Environment Definition: The environment encompasses all elements surrounding us, including plants, animals, land, buildings, factories, and roads. It consists of living organisms as well as inanimate objects.
Natural vs. Human-Made Components: The environment is categorized into two main groups: natural components (like trees, mountains, and lakes) that exist in nature, and human-made components (such as parks, roads, and vehicles) created by humans.

The Natural Environment

The natural environment comprises everything that exists naturally on Earth. It can be categorized into two main types:

• Physical Environment: This includes natural elements such as landforms, water bodies, climate, and air.
• Biological Environment: This encompasses living organisms, including plants, animals, and microorganisms.

Physical and Biological Environment

Physical Environment: The physical environment comprises naturally occurring non-living elements such as land, water, and air.

• The lithosphere is the Earth's rigid outer layer, also known as the crust, primarily composed of rock. It includes diverse landforms like mountains, plateaus, and plains, providing essential resources like minerals and land.
• The hydrosphere represents all water on Earth, covering over 71% of the planet's surface. It sustains life by offering vital water resources above and below ground and in the atmosphere.
• The atmosphere is Earth's gaseous envelope, regulating temperature and supplying life-supporting gases to living organisms.

Biological Environment: The biological environment, or biosphere, is a narrow zone where the lithosphere, hydrosphere, and atmosphere intersect, hosting all life on Earth.

• Ecosystems: Interactions between the biosphere and physical environment give rise to various unique ecosystems.

Ecosystem

Definition of Ecosystem: An ecosystem is a system created by a group of dependent living organisms in a specific place, interacting with the environment.

Size Variation: Ecosystems range from large entities like entire rainforests to small entities like rotting tree trunks.

Diversity: Different physical environments host various ecosystems, each with unique features, leading to diverse ways of organism survival.

Interconnectedness: Every component of an ecosystem is closely linked; any disturbance to one part affects the entire system.

Example: Ecosystem of a Rotting Tree Trunk

• A dead tree trunk decomposes in a warm, moist environment.
• The decomposing tree serves as food for mushrooms and other fungi.
• The fungi become food for insects.
• Insects are prey for frogs and lizards.
• Frogs are consumed by snakes.

Impact of Disruption: Removal of any element from this chain disrupts the entire ecosystem. For instance, without moisture, fungi won't grow, leading to the collapse of the ecosystem.

The Human Environment

The human environment refers to the surroundings shaped or altered by humans. It comprises the built environment and the socio-cultural environment.

Built Environment

• The built environment encompasses all physical structures created by humans, such as houses, factories, farms, and transportation systems.

Socio-Cultural Environment

• The socio-cultural environment includes aspects like family, religion, education, customs, and beliefs of the inhabitants in a region. These elements form the backdrop in which individuals grow up and dwell.

Impact of Human Beings on the Environment

Human Influence on the Environment:

• Most organisms adapt to their surroundings, but humans modify the environment to meet their requirements.
• For instance, humans construct wells, dams, and canals to access water, allowing them to inhabit arid regions.
• They clear forests for agriculture, settlements, and industries, contributing to widespread environmental degradation.
• Activities like deforestation and pollution have caused significant harm, leading to issues like climate change, ecosystem destruction, and species extinction.

Importance of Environmental Preservation:

• To safeguard the planet and maintain ecological balance, it is crucial to harmonize the natural and human environments.
• We must utilize natural resources wisely and responsibly to ensure sustainability and protect the environment.