Trophic Levels in an ecosystem Flashcards
What is biomass?
The total dry mass of all the living organisms in an area.
Why is dry mass used for biomass?
Because the wet mass varies as the volume of water in the organism varies.
How do you calculate the efficiency of biomass transfer?
Efficiency = (energy transferred / total energy available) x 100
What percentage of the incident energy from light for photosynthesis do producers use?
1%.
What percentage of the biomass from one trophic level is transferred to the level above it in feeding?
Approximately 10%.
Why are biomass transfer not 100% efficient?
Energy is lost through:
- Egestion (removal of faeces).
- Excretion (removal of waste products such as urine).
- Respiration for energy for movement and keeping warm.
- Carbon dioxide and water as byproducts of respiration.
- Production of inedible bones and shells.
How does the efficiency of biomass transfers affect the number of trophic levels in a biomass pyramid?
The less efficient the transfers, the fewer trophic levels and the fewer organisms in higher trophic levels.
What is a pyramid of numbers?
A pyramid of numbers shows the number of organisms at each trophic level.
Why is the pyramid of numbers not pyramid shaped?
Pyramid of numbers don’t take size and mass of organisms into account.
