Primary producers, also called autotrophs, are organisms that can produce their own food. Most autotrophs lie at the bottom of the food chain, serving as food sources for animals farther up the line. Primary producers are self-sufficient when it comes to meals: they produce their own food using light, carbon dioxide, water and sometimes other chemicals too.
The process of food creation used by primary producers is called photosynthesis. This food production method involves using energy from the sun to change water from soil and carbon dioxide from the air into glucose, which is a type of sugar and an essential nutrient. Glucose is converted into energy by plants and is also used to produce cellulose, which gives autotrophs the supplies they need to grow and create cell walls. Plants are the most common form of autotroph, although this category includes many other organisms as well. Algae, which live underwater in ocean habitats, are other members of this group as are the various kinds of seaweed. Phytoplankton, which are tiny ocean-dwelling organisms, are also classified as autotrophs, and a variety of bacteria fall into the class of primary producers too. Primary producers exist in habitats worldwide, including temperate and tropical zones and live in water as well as on land.