Net production efficiency (NPE)

Definition

Net production efficiency (NPE) is a measure of how efficiently organisms convert assimilated energy into biomass. It is calculated as the ratio of net secondary production to assimilation in an ecosystem.

5 Must Know Facts For Your Next Test

1. Net production efficiency varies greatly among different types of organisms, with ectotherms generally having higher NPE than endotherms.
2. Higher trophic levels tend to have lower net production efficiency due to increased energy losses at each transfer stage.
3. NPE is influenced by factors such as metabolic rate, growth rate, and the organism's ecological role.
4. It is a key component in understanding energy flow and nutrient cycling within ecosystems.
5. Calculating NPE helps ecologists assess the productivity and sustainability of ecosystems.

Review Questions

• What factors can influence net production efficiency in an organism?
• Why do ectotherms typically have a higher NPE compared to endotherms?
• How does net production efficiency impact the energy flow through an ecosystem?

Related terms

Gross Production Efficiency: The ratio of gross primary or secondary production to ingestion or photosynthetic energy capture.

Assimilation Efficiency: The proportion of ingested food that is assimilated into the body for growth, reproduction, and maintenance.

Trophic Efficiency: The efficiency with which energy is transferred from one trophic level to the next in a food chain.