In this model chain, producers hold 50000 kcal, primary consumers eat the producers, secondary consumers eat the primary consumers, and tertiary consumers eat the secondary consumers. Using the ten percent rule at every transfer, about how much energy is available to the tertiary consumers?
الشرح
Three transfers reduce 50000 kcal to 5000 kcal, then to 500 kcal, and finally to about 50 kcal at the tertiary level. The 500 kcal choice counts only two transfers and therefore gives the figure one level too low.