Dr Rana Hamza Shakil thank you for your contribution to the discussion

A sequence of living organisms which involves the transfer of food energy from producers, through a series of organisms with repeated eating and being eaten is called food chain. Each level or step in a food chain where the transfer of energy takes place is called trophic level. As producers are consumed, roughly 10% of the energy at the producer level is passed on to the next level. The other 90% is used for life processes, such as photosynthesis, respiration, reproduction, digestion; and ultimately transformed into heat energy before the organism is ever consumed.Transfer of food energy from the producers through a series of organisms with repeated eating and being eaten is known as food chain. The food chain consists of producers, primary consumers, secondary consumers, tertiary consumers or top carnivores and decomposers. The producers synthesize food by the process of photosynthesis. A part of the energy is stored within the plants. The remaining energy is utilized by the plants in their growth and development. This stored energy is transferred to the primary consumers when they feed on the producers. The transfer of energy from sun to producer to primary consumer to secondary consumer to tertiary consumer can be shown in a food chain. Dead producers and consumers and their waste products provide matter and energy to decomposers. Decomposers transform matter back into inorganic forms that can be recycled within the ecosystem. So, the energy that enters an ecosystem as sunlight eventually flows out of the ecosystem in the form of heat.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.