Natural systems can be looked at in terms of nodes and relationships, just like engineering systems. Think about the relationship between a cockatoo and the tree that it nests in.
Both the bird and the tree are nodes, and they have a beneficial relationship with each other. The tree gives the cockatoo a hollow to live in and a source of food in the form of nectar. Meanwhile the bird helps the tree grow new saplings by spreading its pollen about.
When both nodes affect each other, this is a feedback loop, where two nodes affect each other at the same time. In this feedback loop the cockatoo and the tree are both helping each other survive.
Systems are examined through “mapping” out the nodes and their relationships to each other. This simple feedback loop can be mapped like this:
