Suppose that a fox feeds only on rabbits, squirrels, mice,

[SaeLk]

Suppose that a fox feeds only on rabbits, squirrels, mice, and seed-eating birds, all of which feed on plant material. How many square meters of plant material are then required to support the fox if the net primary productivity of the plant material is 8000 Kcal/m²/year? Assume that the fox's daily caloric requirement is 800 Kcal, and that only 10% of the energy at one trophic level can be passed on to the next. If the fox were to feed only on insect-eating birds, how many square meters of plant material would be Required.

I got 800(daily cal) x 365(days in yr) = 292000 - 90% = 29200. But I'm not sure if it's right...?

Thank you!

 

[stapel]

Suppose that a fox feeds only on rabbits, squirrels, mice, and seed-eating birds, all of which feed on plant material. How many square meters of plant material are then required to support the fox if the net primary productivity of the plant material is 8000 Kcal/m²/year? Assume that the fox's daily caloric requirement is 800 Kcal, and that only 10% of the energy at one trophic level can be passed on to the next. If the fox were to feed only on insect-eating birds, how many square meters of plant material would be Required.

The fox needs 800 kilo-calories each day. Since only ten percent (one-tenth) of what the plant-eaters consume is passed on to the fox, this means that this "800 Kcal" amount is one-tenth of the Kcal's that the plant-eaters must consume for the fox's benefit. So how much do the plant-eaters need to consume each day?

How much do they need to consume in a year, assuming 365 days in one year?

Since the area, on average, produces only 8000 Kcal per square meter in a year, how many square meters do the plant-eaters need?

(Note: I am assuming that we aren't taking a 90% deduction between the plants and the plant-eaters. But I'm a little fuzzy on "next trophic level"....)

If you get stuck, please reply showing all of your work and reasoning. Thank you.

Eliz.