How materials are cycled

Students should:

• recall that many different materials cycle through the abiotic and biotic components of an ecosystem
• explain the importance of the carbon and water cycles to living organisms.

All materials in the living world are recycled to provide the building blocks for future organisms.

The carbon cycle returns carbon from organisms to the atmosphere as carbon dioxide to be used by plants in photosynthesis.

The water cycle provides fresh water for plants and animals on land before draining into the seas. Water is continuously evaporated and precipitated.

Students are not expected to study the nitrogen cycle.

Students should be able to explain the role of microorganisms in cycling materials through an ecosystem by returning carbon to the atmosphere as carbon dioxide and mineral ions to the soil.

WS 1.2 Interpret and explain the processes in diagrams of the carbon cycle, the water cycle.

There are links with the water cycle to GCSE Chemistry 4.9.1.2 The Earth’s early atmosphere.