Question

Explain why, in an ecosystem, energy is said to flow while nutrients are said to cycle.

Answer 1

In an ecosystem, energy flows in one direction: it enters as solar energy through plants, moves through consumers and decomposers, and finally is lost as heat, which does not return, making energy flow non-cyclic. Nutrients, however, cycle because decomposers continuously recycle them from dead organisms back into the environment, enabling reuse within the ecosystem. Thus, energy flows while nutrients cycle.