Modeling Energy Flows

Three simple ways to model trophic levels

1. Pyramid of numbers
2. Pyramid of biomass
3. Pyramid of energy

Pyramid of numbers

• Reflect the numbers of organisms required to sustain organisms at each trophic level
• Measures organisms' relative abundance
• Some groups of primary consumers consist of large numbers of smaller individuals, i.e. inverted pyramid

Pyramid of biomass

• Provide a standardized measure of flows between trophic levels
• Reflect the amount of energy fixed by different trophic levels at a particular point in time
• Comparative resource requirements of tertiary consumers become apparent, and can be standardized in units of, e.g., vegetation

Pyramid of energy

• Reflect actual energy flows between trophic levels
• Losses to entropy can also be measured, significance becomes apparent
• Can be used to compute energy budgets