A sequence of different organisms in which one is being eaten by other is called food chain. In a food chain organisms green plants which uses solar energy to prepare their food are called producers. Producers are the source of food for the herbivores or Plant eaters. They are primary consumers and those animals which are carnivores eating herbivores are secondary or tertiary or top consumers depending on the length of a food chain. If producer population decreases then there will be lack of food for herbivores. Therefore herbivore population will decrease in want of food.
