It is observed that plants accept inorganic substances and manufactures food by respiration the process of photosynthesis. A small portion of the food produced by the plants is used by them and the rest is reserved in the body. The herbivorous animals eat this and gradually herbivores are eaten by the carnivorous animals. The decomposers transform the plants, herbivorous and carnivorous animals into inorganic substances.
Using the inorganic, substance the green plants can again manufacture food with the help of solar energy. In an ecosystem, the transfer or flow of energy and nutrient from one trophic level to other is in succession. In each trophic level of food chain energy available decreases step by step, decomposers rot the dead body of the organisms and inorganic nutrients are stored in the nutrient storage of environment.
The green plants again find inorganic nutrients from the storage environment. The cyclic flow of nutrients is known as nutrient flow. Food chain and nutrient flow are the important characters in the ecosystem.