Physical Geography
Landforms, Atmosphere, Hydrosphere and Biosphere
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Overview
Physical Geography forms the foundation of understanding Earth's natural systems and is a core component of the Social Science paper in GTET Paper-II. This topic covers four interconnected spheres—lithosphere (landforms), atmosphere, hydrosphere, and biosphere—and their interactions that shape our planet's surface and sustain life.
For GTET, students must understand the formation and types of major landforms, the structure and composition of the atmosphere, the distribution and cycle of water on Earth, and the zones of life in the biosphere. Questions typically test factual knowledge of layers, features, and processes rather than deep theoretical understanding. Expect direct questions on atmospheric layers, types of landforms, ocean features, and ecological zones.
Mastering this topic also builds the conceptual base for Geography of India and Gujarat sections, making it doubly important for exam success.
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Key Concepts
- **Lithosphere** refers to Earth's solid outer layer comprising the crust and upper mantle; it is broken into tectonic plates whose movement creates mountains, earthquakes, and volcanoes.
- **Landforms** are natural features on Earth's surface created by internal forces (earthquakes, volcanism) and external forces (weathering, erosion, deposition) acting over time.
- **Atmosphere** is the gaseous envelope surrounding Earth, held by gravity, extending about 10,000 km but with 99% of mass within 30 km of the surface.
- **Atmospheric layers** from surface upward: Troposphere → Stratosphere → Mesosphere → Thermosphere → Exosphere—each with distinct temperature patterns and characteristics.
- **Hydrosphere** includes all water on Earth—oceans (97.5%), ice caps and glaciers (1.75%), groundwater, rivers, lakes, and atmospheric moisture—continuously cycling through evaporation, condensation, and precipitation.
- **Biosphere** is the narrow zone where lithosphere, atmosphere, and hydrosphere interact to support life, extending from ocean floors to about 10 km above sea level.
- **Weathering vs Erosion**: Weathering breaks down rocks in place; erosion involves movement and transport of weathered material by water, wind, or ice.
- **Water Cycle (Hydrological Cycle)** connects all water bodies through evaporation, transpiration, condensation, precipitation, and runoff—essential for understanding climate and water resources.
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