Discussion questions
1. at any given time, a 4-acre field contains an average of 200 kg dry weight of mallow plants. for these
calculations, assume that the food chain shown below is isolated and that there are no other predators
or sources of food involved.
mallow plant + painted lady butterfly → phoebefox
assume that the dry weight of each animal is on average as indicated below:
painted lady butterfly
phoebe
fox
a. assuming that 10% of the biomass, as measured in dry weight, is transferred from one trophic
level to the next higher level, calculate how many foxes the field could support at any given
time. show your work and include in your calculations how many phoebes and painted lady
butterflies the field could support.
0.18
4.08
1.0 kg
b. construct a biomass pyramid diagram depicting the food chain described in 1.a. (i. e., butterfly,
phoebe, fox). include only the organisms of the food chain that the 4-acre field will support, and
label the trophic level that each organism occupies. the units in your pyramid should be grams
per square meter (g/mº).
note: 1 acre = 4046.86 square meters.