Energy Flow and Transformations

 • In an Ecosystem, energy flow is unidirectional.

• Ecological pyramids are graphic representations of feeding relationship. The pyramid may be constructed by plotting the number, biomass or energy content of the organisms at each trophic level.

 • Living organisms are energy converters. When they convert energy from one form to another, some energy is always lost ad heat. This is accordance with the laws of thermodynamics.

 • Only a quarter of energy absorbed by primary producers is converted into chemical energy (food). About one third of this chemical energy is used by the producers; the rest (net primary productivity of the ecosystem) is available to the rest of the consumers in the food chain. Generally, primary consumers (herbivores) are less efficient energy converters than secondary consumers (carnivores).