The majority of life on Earth is based on a food web which revolves around the Sun, as plants use sunlight to make food via photosynthesis. However, in environments where there is no sunlight and thus no plants, organisms instead rely on primary production through a process called chemosynthesis, which runs on chemical energy. Together, photosynthesis and chemosynthesis fuel all life on Earth. In this lesson, students use models to illustrate how photosynthesis and chemosynthesis transform energy (light and chemical) into stored chemical energy in order to answer the Driving Question: How does the chemical process of chemosynthesis compare to the process of photosynthesis?