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Trophic Transfer Explorer

Explore how energy flows through ecosystems from producers to top predators. Visualize energy, biomass, and number pyramids, adjust transfer efficiencies, and discover why food chains rarely exceed four trophic levels.

Energy Pyramid

EagleTertiary Consumers4.0 kcal/m²/yr0% →FoxSecondary Consumers40.0 kcal/m²/yr10% →RabbitPrimary Consumers400.0 kcal/m²/yr10% →GrassProducers4000.0 kcal/m²/yrEnergy decreases ~90% at each trophic levelEnergy Flow
Grass→Rabbit→Fox→Eagle

Controls

Gross Primary Productivity (GPP)8,000 kcal/m²/yr
Plant Respiration Fraction50%
Producers → Primary Consumers10%
Primary → Secondary Consumers10%
Secondary → Tertiary Consumers10%

Energy Calculations

NPP=GPP×(1−Rf)=8,000×0.50=4000 kcal/m2/yr\mathrm{NPP} = \mathrm{GPP} \times (1 - R_f) = 8,000 \times 0.50 = 4000 \text{ kcal/m}^2\text{/yr}
En=En−1×ϵnE_n = E_{n-1} \times \epsilon_n

Energy at Each Trophic Level

Grass4000.0 kcal/m²/yr
Rabbit400.0 kcal/m²/yr(10.00% of producers)
Fox40.0 kcal/m²/yr(1.00% of producers)
Eagle4.0 kcal/m²/yr(0.10% of producers)
GPP
8,000 kcal/m²/yr
NPP
4000 kcal/m²/yr
Total Respiration
4000 kcal/m²/yr
Overall Efficiency
0.1000%

Ecological Efficiency

ηeco=EtopEproducers=4.004000.00=0.1000%\eta_{\text{eco}} = \frac{E_{\text{top}}}{E_{\text{producers}}} = \frac{4.00}{4000.00} = 0.1000\%

The 10% Rule

On average, only about 10% of the energy at one trophic level is transferred to the next. The remaining 90% is lost as heat through metabolic processes (cellular respiration). This is why food chains rarely have more than 4-5 trophic levels.

Reference Guide

The 10% Rule

On average, only about 10% of the energy available at one trophic level is transferred to the next. The other 90% is lost mainly as heat through cellular respiration.

Transfer equation
En=En−1×ϵnE_n = E_{n-1} \times \epsilon_n

This exponential decline in available energy limits most food chains to 4 or 5 trophic levels. A fifth level would receive only 0.01% of the original producer energy.

Energy Pyramids

Energy pyramids always have a broad base and narrow top because energy is lost at every level. Unlike biomass or number pyramids, energy pyramids can never be inverted.

Three types of ecological pyramids
  • Energy always upright, shows kcal/m²/yr
  • Biomass can be inverted in aquatic systems
  • Numbers can be inverted (one tree supports many insects)

Gross vs Net Primary Productivity

Gross Primary Productivity (GPP) is the total rate of photosynthesis. Plants use 40-60% of GPP for their own respiration. What remains is Net Primary Productivity (NPP), the energy available to consumers.

Productivity relationship
NPP=GPP−Ra=GPP×(1−Rf)\mathrm{NPP} = \mathrm{GPP} - R_a = \mathrm{GPP} \times (1 - R_f)

Tropical forests have high GPP (~25,000 kcal/m²/yr) but also high respiration. Open oceans have low GPP (~2,000 kcal/m²/yr) but cover huge areas.

Ecological Efficiency

Ecological efficiency measures how effectively energy moves through the entire food chain. It is the ratio of energy at the highest trophic level to energy at the producer level.

Overall efficiency
ηeco=EtopEproducers=∏i=1nϵi\eta_{\text{eco}} = \frac{E_{\text{top}}}{E_{\text{producers}}} = \prod_{i=1}^{n} \epsilon_i

Aquatic ecosystems tend to have slightly higher trophic efficiencies (15-20%) than terrestrial ones (5-10%) because aquatic producers (phytoplankton) invest less energy in structural support tissue.