An organism may play more than one role in an ecosystem. Organisms that break down wastes and dead organisms and return the raw materials to the environment are called decomposers. As decomposers obtain energy for their own needs, they return simple molecules to the environment to be used again by other organisms. The flow of energy in an ecosystem follows the 10% rule, meaning only 10% of the energy is transferred to the successive trophic level and the rest is lost in the atmosphere. The energy is produced by the autotrophs, as they have photosynthetic pigments to harness the sunlight into chemical energy via photosynthesis. Organisms make their own food, which creates energy for them to grow, reproduce and survive. Being able to make their own food makes them unique; they are the only living things on Earth that can make their own source of food energy. Organisms are the only life forms that can produce their own food using energy from sunlight. Plants have green pigment called chlorophyll in their cells, mainly in the leaves. This pigment allows plants to make food from sunlight, water and carbon dioxide in a process called photosynthesis. Energy enters the food chain when producers absorb light energy and convert it into chemical energy during photosynthesis. The energy is used for the plant for growth and becomes biomass

Producers as plants, algae, and cyanobacteria use the energy from sunlight to make organic matter from carbon dioxide and water. This establishes the beginning of energy flow through almost all food webs. Producers are organisms that produce their own energy from sunlight. Producers turn sunlight, water, and carbon dioxide into food in the form of a sugar. Primary producers use energy from the sun to produce their own food in the form of glucose, and then primary producers are eaten by primary consumers that are in turn eaten by secondary consumers, and so on, so that energy flows from one trophic level, or level of the food chain, to the next. During the process of energy flow in the ecosystem, plants being the producers absorb sunlight with the help of the chloroplasts and a part of it is transformed into chemical energy in the process of photosynthesis. The bottom and largest level of the pyramid is the producers and contains the largest amount of energy. As you move up the pyramid, through the trophic levels to primary, secondary and tertiary consumers, the amount of energy decreases and the levels become smaller. Organisms may play only one role in an ecosystem. How does most of the energy enter an ecosystem? Each of the organisms in an ecosystem fills the energy role of producer, consumer, or decomposer. Second-level consumers feed on the first-level consumers, and the movement of energy is from the first-level to the second-level consumers; they may be carnivores or omnivores. An organism may play more than one role in an ecosystem. Organisms that break down wastes and dead organisms and return the raw materials to the environment are called decomposers. As decomposers obtain energy for their own needs, they return simple molecules to the environment to be used again by other organisms. An organism's role within an ecosystem depends on how it obtains its food. Plants and animals obtain their food in very different ways, so they have very different roles in an ecosystem. The way in which an organism obtains food also affects its interactions with other organisms in the ecosystem.

Energy is transferred between organisms in food webs from producers to consumers. The energy is used by organisms to carry out complex tasks. The vast majority of energy that exists in food webs originates from the sun and is converted into chemical energy by the process of photosynthesis in plants. During the process of energy flow in the ecosystem, plants being the producers absorb sunlight with the help of the chloroplasts and a part of it is transformed into chemical energy in the process of photosynthesis. The flow of energy from an ecosystem to an organism and from one organism to another is called energy flow. Producers and organisms that produce food in the form of carbohydrates during photosynthesis. There is a flow of energy from one trophic level to the other in a food chain. Producers bring energy from the sun into the community. Primary consumers eat the producers, which makes them herbivores in most communities. Secondary consumers eat the primary consumers, which makes them carnivores. The flow of energy in an ecosystem is always unidirectional. It is said to be unidirectional because some energy is lost in form of heat when moving from one trophic level to the next for the maintenance of the homeostasis of an organism. An organism may play more than one role in an ecosystem. Organisms that break down wastes and dead organisms and return the raw materials to the environment are called decomposers. As decomposers obtain energy for their own needs, they return simple molecules to the environment to be used again by other organisms. The living organisms in an ecosystem can be divided into three categories: producers, consumers and decomposers. They are all important parts of an ecosystem.