Energy Losses Restrict the Number of Trophic Levels in Ecosystems
- As only 10% of energy is transferred between trophic levels, less energy is available for higher trophic levels.
- These energy losses are the reason why the number of trophic levels in food chains are limited.
- Remember: Energy flows, matter cycles.
- Energy enters as sunlight and exits as heat, while matter is recycled within ecosystems.
Sustaining Trophic Levels Become Highly Inefficient
- Essentially, this boils down to:
- Energy Depletion: As energy diminishes at each level, it becomes insufficient to sustain another level.
- Smaller Populations: Higher trophic levels support fewer organisms because they require more energy-rich food.
- Decreasing Biomass: While biomass decreases up the chain, energy content per unit mass often remains constant or even increases due to fat and protein concentration.
- Two-Stage Food Chain: I
- n East Africa, Senegalia mellifera trees provide food for African bush elephants.
- These elephants have no natural predators, limiting this chain to two stages.
- Five-Stage Food Chain:
- In the North Atlantic, phytoplankton are consumed by copepods, which are eaten by sand eels, followed by mackerel, and ultimately consumed by bluefin tuna.
- Most energy dissipates before reaching apex predators.
Recall how this explains how pyramids of energy are structured.
Self review- Why does heat loss occur during cellular respiration?
- How does energy inefficiency limit the number of trophic levels in an ecosystem?
- What role does heat loss play in the survival of warm-blooded animals?
