Glynn Gorick: "Sunlight Harvesting" Sunlight provides the energy for almost all life on Earth. It is harvested by plants, including microscopic algae living in water. Photons of sunlight (represented as red dots) enter the food producing regions within the algal cell which act like solar panels. Here the molecules of the green pigment, chlorophyll, are arranged in clusters and absorb the energy of the photons. That energy is used to turn carbon dioxide and water into food, releasing excess oxygen. Algae are eaten by daphnia ('water fleas') and these are caught by roach, small fish which are preyed on by herons. The heron ultimately depends on a vast number of algal cells to supply it with food. The scale of sizes in the painting gradually changes from the magnified part of a single algal cell, covering the lower third of the painting, to the Earth's atmosphere at the top of the painting. The oxygen in our atmosphere was itself created by ancestral forms of algae, beginning millions of years ago, when they were among the most advanced life forms on earth. They changed the ancient atmosphere of the Earth, making it possible for oxygen-breathing animals to evolve. Even today, about 90% of all oxygen production and carbon dioxide use is carried out by algae living in the seas and freshwaters.