To estimate how much energy an apex predator would receive from the 3,500 kilocalories of energy produced by primary producers (such as plants), we can use the concept of trophic levels and the energy pyramid.
Typically, only about 10% of the energy at one trophic level is transferred to the next level. This is known as the 10% rule. So, if the producers (plants) have provided 3,500 kcal of energy, the energy available to herbivores (primary consumers) would be roughly:
\[ \text{Energy for herbivores} = \text{Energy from producers} \times 0.10 = 3,500 , \text{kcal} \times 0.10 = 350 , \text{kcal} \]
Then, if we assume that the energy for herbivores is then transferred to carnivores (secondary consumers) with the same 10% efficiency, the energy available to secondary consumers would be:
\[ \text{Energy for secondary consumers} = \text{Energy for herbivores} \times 0.10 = 350 , \text{kcal} \times 0.10 = 35 , \text{kcal} \]
Finally, if we consider the apex predator (which would be at the top of the food chain) and assume it also receives energy from the secondary consumers, again using the 10% rule:
\[ \text{Energy for apex predator} = \text{Energy for secondary consumers} \times 0.10 = 35 , \text{kcal} \times 0.10 = 3.5 , \text{kcal} \]
Therefore, the apex predator would receive approximately 3.5 kilocalories from the original 3,500 kilocalories of energy produced by primary producers.