I. General terms and definations
Consumers include all of the species which recieve their energy through other organisms.
All organisms within the same trophic level obtain their energy from similar sources (sun, plants, herbivores, etc.)II. Ecological efficiency
Like primary production we can consider how efficiently energy is passed from from one trophic level to the next. For example, how efficiently is energy passed from grass to buffalo or from buffalo to wolves?
A. Where is energy lost?
B. What is remaining energy used for?
Metabolized energy is termed assimilation
Assimilated energy is used for:
maintainance (resting energy, activity energy)
production (growth, reproduction)
Only this last category represents the energy which can be passed on to the next trophic level.
C. Ecological efficiency calculations
1. Within a trophic level
Production efficiency = production / assimilation
values range from 0.86% (insectivores) - 55.6% (carnivorous insects)
2. Between trophic levels
Lindeman's Efficiency =
assimilation at trophic level n assimilation at trophic level n-1
values range from 15-20%
Consumption Efficiency =
gross energy intake at trophic level n production at trophic
n-1 values range from 20-25%
D. On average 90% of energy is lost when passing from one trophic level to the next.
Created 2 September 2011, Last Update 02 September 2011
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