Pigmentation occurs in nearly all living organisms.
The red and yellow colors of autumn foliage are due to the exposure of the anthocyanins after the green chlorophyll pigments, which usually mask them, have decomposed and faded. The latter three produce the surface coloration of most animals. Pigments not only provide external coloration but also function in some important physiological processes. Among its other functions, carotene operates in the synthesis of vitamins and of chlorophyll. Chlorophyll is essential for plant photosynthesis .