NCERT Notes: Grade 6 Social Science - Chapter 5: Major Domains of the Earth
Introduction
The Earth, a complex and dynamic entity, is comprised of several domains. These major realms include the lithosphere, atmosphere, hydrosphere, and biosphere. Each domain has its characteristics, but they’re intricately linked, ensuring the balance and sustenance of life.
The Lithosphere
The lithosphere is the solid outermost shell of our planet.
- Components: It encompasses the continents and the ocean basins.
- Mountains & Plains: The lithosphere’s undulating structure results in various landforms like mountains, plateaus, and plains.
- Minerals & Resources: This domain is abundant in minerals and resources, vital for human sustenance.
The Atmosphere
Enveloping the Earth is the blanket of air known as the atmosphere.
- Composition: Primarily made of nitrogen and oxygen, it also contains small amounts of carbon dioxide, helium, ozone, and water vapour.
- Weather & Climate: The atmosphere is responsible for our weather patterns and climate. Its lower layer, the troposphere, is where we experience weather phenomena.
- Protection: It protects life on Earth by absorbing ultraviolet rays from the sun and acting as a shield against meteors.
The Hydrosphere
Water, essential for life, makes up the hydrosphere.
- Oceans: Covering about 71% of the Earth, the vast oceans (Pacific, Atlantic, Indian, Southern, and Arctic) hold saltwater.
- Rivers, Lakes & Ice Caps: Freshwater sources, they play a pivotal role in human civilization and the ecosystem. The polar regions have enormous ice caps, which are freshwater reserves.
- Biodiversity: Oceans harbor a wide array of marine life, contributing significantly to the Earth’s biodiversity.
The Biosphere
Where the lithosphere, atmosphere, and hydrosphere converge, life exists. This realm is the biosphere.
- Life: It’s a narrow zone where air, water, and soil combine to support life. It has humans, animals, plants, microorganisms, etc.
- Ecosystems: Different ecosystems, from dense forests to barren deserts, from deep ocean floors to high mountain peaks, all fall within the biosphere.
Interdependence of the Domains
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Water Cycle: The hydrosphere and atmosphere interact to create the water cycle. Water evaporates from the Earth’s surface, forms clouds, and returns as precipitation.
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Geological Activities: The lithosphere impacts the atmosphere through volcanic eruptions, which release gases into the air.
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Climate Regulation: Oceans, part of the hydrosphere, regulate the Earth’s climate by absorbing heat and redistributing it.
Human Interaction with Earth’s Domains
Humans have always interacted with these domains. However, excessive exploitation is leading to environmental issues.
- Deforestation: Cutting down forests (biosphere) impacts the atmosphere, leading to global warming.
- Pollution: Dumping waste in rivers (hydrosphere) affects aquatic life and the quality of freshwater.
- Mining: Extracting minerals from the lithosphere can lead to land degradation and environmental imbalance.
Conclusion
The Earth’s major domains are not just geographical classifications but represent a world of interconnections. Their balance ensures life’s continuity. As custodians of the Earth, it is our duty to understand, respect, and sustain these domains.
Reference: NCERT Grade 6 Social Science - Chapter 5: Major Domains of the Earth
Note: This article offers an SEO-optimized summary of Earth’s major domains and their significance. For a comprehensive study, students are encouraged to refer to the original NCERT textbook.