Creating sustainable futures/CSF101/Holocene to Anthropocene/How the biosphere works

The biosphere is the living part of the Earth - where all ecosystems and living organisms are found - of which humans are just one of over 8 million species.

Biological cycles
Biological cycles are what sustains life on Earth. On land, and at a basic and very simplified level, the cycle can be described in two parts. Plants use energy from the sun to fuel their growth using photosynthesis. This process takes carbon dioxide from the air, water and minerals from the soil and turns them into cellular structures. The plants provide food and oxygen is produced as a by-product of the process.

In the second part of this simplified process animals, including humans, eat the plants to fuel their own cellular growth and to provide nutrition for their survival. Organic waste from animals is returned to the environment which plants can then re-use as ‘food’. Animals also consume the oxygen produced by plants to breathe and produce carbon dioxide as a by-product.

Photosynthesis is a critical component of this cycle. Plants take energy from outside of the Earth’s system and use it to structure different chemicals into a useful structure that forms the basis of the food chain for animals. Many of the materials used by plants in this process might be considered as ‘waste’ products which are essentially ‘cleaned up’ and recycled. So, using ‘free’ solar energy, plants create net value and provide the basic building blocks for animal life.