Final answer:
The energy available at the producer level in a food chain is the highest because all other organisms depend on it. To calculate the energy at the producer level, the energy available at the third trophic level is divided by the energy transfer efficiency.
Step-by-step explanation:
In a food chain, the energy flow starts with the producers, which are the plants. The producers convert sunlight into energy through photosynthesis. The energy available at the producer level is the highest in the food chain because all other organisms depend on it for energy.
To determine the amount of energy available at the producer level, we need to consider energy transfer from one trophic level to another. Each trophic level loses energy as it is transferred to the next level. The energy transfer efficiency is usually around 10%. So, to calculate the energy available at the producer level, we divide the energy available at the third trophic level by the energy transfer efficiency.
Given that the energy available at the third trophic level is 100 joules, we can calculate the energy available at the producer level as follows:
Energy available at the producer level = Energy available at the third trophic level / Energy transfer efficiency
= 100 joules / 0.1
= 1000 joules