Earth as a System

• Earth can be considered as a system consisting of several interconnected subsystems or spheres, through which matter and energy are transferred.

• The four main spheres are:

• The lithosphere (also known as the geosphere) – the solid, outer layers of Earth, including the crust and upper mantle.

• The hydrosphere – all locations on Earth that contain water – as liquid water, ice or water vapour.

• The atmosphere – a mixture of gases, collectively known as air, that forms a layer around Earth.

• The biosphere – all parts of Earth where living organisms are found.

• Earth’s spheres are not separate, isolated systems. Instead they overlap and interact in many complex ways.

• In this lesson we will look at each of Earth’s four main spheres.

• In the following lesson will look at interactions between Earth’s spheres.

Earth is a system consisting of the lithosphere (land), hydrosphere (water), atmosphere (air) and biosphere (living things).

(Images: NASA, Wikimedia Commons; Astrid Simanca, Pexels; Rob Wilkinson, Adobe Stock; lukyeee_nuttawut, Adobe Stock; chokchaipoo, Adobe Stock)