An is an organism capable of producing its own food from inorganic substances, such as carbon dioxide and water, using energy from light or chemical reactions. Derived from the Greek words auto ("self") and troph ("nourishment"), they are known as primary producers because they form the foundational base of almost every food chain on Earth. Types of Autotrophs Autotrophs are classified by their energy source: autotroph - Students | Britannica Kids | Homework Help