Gaia can be represented in many variations, for example as a Simple Ecology.
In this ecosystem, the Atmosphere functions as a storehouse for the Oxygen and Carbon Dioxide needed by plants and animals. The lake is a Body of Water that serves as a usable storehouse of Water. The Land includes Soil where Organic Matter is broken down for recycling.
Lettuce is a plant that uses some of the received Solar Energy to drive the conversion of Water and Carbon Dioxide into sugars such as Sucrose and Glucose. Some of the other Photons in the Solar Energy are reflected off the Lettuce, and are sent to me as Visible Light.
I am a Human Being. I breath Oxygen, drink Water, watch the world around me, process the information that I can sense, eat Lettuce, and eliminate Wastes.