Earth, A Unique Life Sustaining Planet

Overview

Earth is the only known planet that supports life. This chapter explains the features that make Earth special, its different spheres, natural resources, and the need to protect our planet.

Key concepts

• Earth has air, water, and a suitable temperature for life.
• Earth has four spheres: atmosphere, hydrosphere, lithosphere, and biosphere.
• The atmosphere provides air and protects from harmful rays.
• Natural resources can be renewable or non-renewable.
• Conservation of resources keeps Earth fit for life.

Important terms / formulae

• Atmosphere: the layer of air around Earth.
• Hydrosphere: all the water on Earth.
• Biosphere: the zone where life exists.
• Renewable resource: a resource that can be replaced naturally.

Solved example or key process

The biosphere is where the atmosphere, hydrosphere, and lithosphere overlap, giving living things air to breathe, water to drink, and land to live on. Because all three meet at the right temperature, Earth can sustain life, unlike other planets in our solar system.

Important questions

1. What features make Earth suitable for life?
2. Name the four spheres of the Earth.
3. Differentiate between renewable and non-renewable resources.
4. Suggest two ways to conserve natural resources.

Quick revision

Earth is unique because it has air, water, and the right temperature for life. Its atmosphere, hydrosphere, lithosphere, and biosphere together support living things. We must conserve resources to keep Earth our living home.