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An Introduction to Ecosystems

When you think about the Great Barrier Reef, what comes to mind? You might think of water, Coral or Fish? All these things make up the ecosystem of the Great Barrier Reef. Even the water!


  1. What is an ecosystem? 
  2. What are abiotic factors?
  3. What are biotic factors?
  4. How do living and non-living factors interact?


An ecosystem is the whole environment of multiple organisms. It includes living organisms, like fish, bacteria or birds, and non-living components like climate, soil, salinity and water. Living organisms are called biotic factors, while non-living components are called abiotic factors. 

Abiotic Factors

Abiotic factors are things which aren’t living. In an ecosystems abiotic factors could be the:

  • climate & light – the temperature and the amount of light is very important in determining which species can survive in the ecosystem.
  • soil – the soil type is important as this provides nutrients that will support different plants.
  • water – the amount of water available in an ecosystem will determine what plants and animals can be supported.
  • atmosphere – animals and other creatures breathe oxygen or filter it from water, and plants grow because of the presence of carbon dioxide.


Interactions between living and non-living

The biotic factors in an ecosystem have a complex relationship with the abiotic components. Changing one will lead to a change in the other. Let’s use a fresh water pond as an example of how the abiotic and biotic factors interact. Select the ‘i’ icons on the image below to see how biotic and abiotic factors work together. As you read the information below, think about what would happen if the oxygen, temperature or light levels changed. 


  • An ecosystem is the interaction of all living and non-living things in an area. 

  • Abiotic are non-living things.
  • Biotic are living things.
  • Non-living things and living things depend on each other. Changes in one can have major impacts on the other. 

Test your knowledge

Click the ‘question mark’ to test your knowledge with some questions and activities.


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