Autotrophs & Heterotrophs
Autotrophs are organisms that can produce their own food from the substances available in their surroundings using light (photosynthesis) or chemical energy (chemosynthesis). Autotrophs are usually plants; they are also called "self feeders" or " primary producers". Heterotrophs cannot synthesize their own food and rely on other organisms, both plants and animal, for nutrition.
The basic definition is that autotrophs obtain carbon from inorganic sources like carbon dioxide while heterotrophs get their reduced carbon from other organisms.