In a typical terrestrial food web, which of the following would provide a wolf with the greatest amount of energy if consumed directly?

• A. Grass
• B. Carnivorous hawk
• C. Herbivorous deer
• D. Fungi

Answer: (C)

Verified step by step guidance

1. Understand the concept of energy transfer in a food web: Energy flows through trophic levels in a food web, starting from producers (like grass) to primary consumers (herbivores) and then to secondary and tertiary consumers (carnivores). Energy decreases as it moves up the trophic levels due to energy loss as heat and metabolic processes.
2. Identify the trophic levels of the organisms listed: Grass is a producer, herbivorous deer is a primary consumer, fungi are decomposers, and a carnivorous hawk is a secondary or tertiary consumer.
3. Recall the 10% rule of energy transfer: Only about 10% of the energy from one trophic level is passed to the next. For example, a wolf consuming a primary consumer (herbivorous deer) would receive more energy than consuming a secondary or tertiary consumer (carnivorous hawk).
4. Evaluate the energy content of each option: Grass provides energy directly to primary consumers, but a wolf cannot digest grass efficiently. Fungi recycle nutrients but do not provide significant energy to a wolf. A carnivorous hawk is higher on the food chain, meaning less energy is available. Herbivorous deer, as a primary consumer, would provide the greatest amount of energy to the wolf.
5. Conclude that the herbivorous deer is the correct answer because it is a primary consumer and closest to the producers in the food web, ensuring the wolf receives the maximum energy if consumed directly.