This statement describes a fundamental principle in ecology called the "10% rule". It means that only about 10% of the energy from one trophic level is transferred to the next higher trophic level. The rest of the energy is lost as heat or used for metabolic processes.

Here's how it works in a food chain:

1. Producers (plants) capture energy from the sun through photosynthesis. They contain the most energy in the food chain.

2. Primary consumers (herbivores) eat plants and obtain about 10% of the energy stored in those plants.

3. Secondary consumers (carnivores) eat herbivores and obtain about 10% of the energy stored in those herbivores.

4. Tertiary consumers (top predators) eat carnivores and obtain about 10% of the energy stored in those carnivores.

Therefore, as the food chain lengthens, the amount of energy available at each subsequent level decreases. This limits the number of trophic levels that a food chain can support and explains why there are fewer top predators than producers in an ecosystem.

Consequences of the 10% rule:

* Limited energy availability: Less energy is available for organisms at higher trophic levels, making them more susceptible to environmental changes.

* Pyramid of numbers: Fewer organisms exist at higher trophic levels.

* Biomass decrease: The total weight of living organisms decreases at higher trophic levels.

* Food web stability: The 10% rule contributes to the stability of food webs, as a small change in the population of one species can have a significant impact on higher trophic levels.

In summary, the 10% rule demonstrates the importance of energy flow and its impact on the structure and function of ecosystems.