4.5c)- Pyramids

Three types of pyramids covered:

• Pyramids of number
• Pyramids of biomass
• Pyramids of energy transfer

1. Pyramids of number
• Illustrates the number of organisms at each trophic level
• Some problems are:
• Not effective at showing energy transfer
• Effective but have some problems
2. Pyramids of biomass
• Bio= 'Living'
• Mass='g/kg'
• Based on dry mass
• Measured in kg/area (km squared)
• Hard to carry out experiments to find out dry biomass
3. Pyramids of energy transfer
• Show the movement of energy from one trophic to the next
• Cannot be inverted (Advantage)
• The reduction at each trophic level shows the measure off efficiency
• Unit of energy- J/kJ
• Unit of area- m squared
• Unit of time- minutes/seconds/years
• Problem- time consuming

• Pyramid of number> biomass> energy