How Energy Moves Through an Ecosystem
Energy in an ecosystem flows in a one-way direction, primarily starting from the sun. Producers (like plants) capture solar energy through photosynthesis and convert it into chemical energy. This energy is then transferred to consumers (animals) when they eat plants or other animals. At each step, some energy is lost as heat due to metabolic processes, following the laws of thermodynamics.
The movement of energy can be visualized as a food chain or food web, and the efficiency of energy transfer between trophic levels is typically low (about 10%).
Worked Example: Calculating Energy Transfer
Suppose a grassland ecosystem receives $10,000$ joules (J) of energy from the sun. Let's calculate how much energy is available \to each trophic level, assuming $10%$ efficiency at each step. **Step 1: Energy captured by producers (plants)** If plants capture $1%$ of solar energy: %%MATH_DISPLAY_0%% **Step 2: Energy transferred \to primary consumers (herbivores)** %%MATH_DISPLAY_1%% **Step 3: Energy transferred \to secondary consumers (carnivores)** %%MATH_DISPLAY_2%% ## Takeaways - Energy flows through an ecosystem from the sun \to producers, then \to consumers, and is lost as heat at each step. - Only about $10%$ of energy is transferred from one trophic level to the next.
- This inefficiency limits the number of trophic levels in an ecosystem.