BI-1954
Pyramids of numbers and biomass
Biology · Secondary 4 · Medium · Pyramids of numbers and biomass
A pyramid of biomass for a pond ecosystem is widest at the base (phytoplankton) and narrowest at the top (herons). Which reason best accounts for this shape?
- Energy is lost at each trophic level, so less biomass can be supported higher up the food chain.
- Herons reproduce more slowly than phytoplankton, so their biomass must be smaller.
- Phytoplankton are larger organisms, so they always have the greatest biomass.
- Energy is gained from predators to prey, so biomass decreases towards the base.
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