Suppose a fox in a food web feeds only on rabbits, squirrels, mice and birds, all of which feed exclusively on plant material. Assuming that a fox’s daily caloric requirement is 800 kcal, and that only 10 percent of the energy at one trophic level can be passed to the next trophic level. How many square meters of plant material are required to support the fox, if the net primary productivity of the plant material is 8,000 kcal/m2/yr? Hint: draw the food chain to determine how many kcal/m2/yr the fox receives to determine how much land he needs and remember the 10% rule!