Modeling Energy Flows

Pyramid of Numbers

Pyramid of Numbers

Uses of Number Pyramids

• 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

Pyramid of Biomass

Uses of Biomass Pyramids

• 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

Pyramid of Energy

Uses of Energy Pyramids

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