Plants, algae, cyanobacteria and some archaea get their supply of energy directly from sunlight.
All organisms that are not green must eat other organisms to get the energy they contain.
The many kinds of lives that share the earth live by eating each other.
Life on earth is a system of Energy Transfer and Sharing
In human terms, transferring energy is called
"making a living."
As living things on Earth make their livings, chemical energy transfers from life to life to life.
This transfer is called a food chain. (Each step in the food chain is called a trophic level.)
