An organism that can create its own food is termed an autotroph. Autotrophs, like plants, use processes such as photosynthesis to convert light energy into chemical energy, producing food from carbon dioxide and water. These organisms are essential to ecosystems, providing energy and organic matter for heterotrophs, which cannot synthesize their own food and rely on autotrophs for nutrition. Autotrophs play a crucial role in the food web and contribute significantly to the balance of oxygen and carbon dioxide in the atmosphere.