Everything we eat, if very simply put is made of sunlight and minerals.
At the bottom of the food-chain or food web, we have minute organisms who quite literally harvest their energy from the sun in the form of photon energy. As we move up the food-chain, we see a transfer of the energy to the next level by mineral compounds, but at every level, the sun continues to be harvested by the organisms that proceed the last. One reason for this is the transfer of energy from the minerals is not sufficient for optimum survival.
As you can see from the chart below, energy comes from food and sunlight.
- The trophic level of an organism is the position it occupies in a food web. A food chain is a succession of organisms that eat other organisms and may, in turn, be eaten themselves.
- The trophic level of an organism is the number of steps it is from the start of the chain.
- Photon energy is light energy, and it permeates the Earth in waves.