KRILL
The Krill is Gone!
A Problem Set About Ecosystem Energy Flow
Directions: Work out the answers to each of the following in your journal. Show all work
& circle the answers. Don’t glue this page in your journal; it’s too big & we can reuse it.
1.
When you eat a piece of Kentucky Fried Chicken, what is your trophic level?
2.
A field of clover supports a population of mice, which supports a population of cats. For every 1000
kilocalories (kCal) of new clover grown, how many kCal of mice could be added? how many kCal of cat?
3.
Why, in our Douglas fir cones (“Mite This Be Home?”) did we find so many more springtails than
pseudoscorpions or centipedes? (HINT: on the Serengeti, why do zebras outnumber lions?)
4.
For every pound of human, how many pounds of grain-fed beef must be consumed? How many pounds of
grain are required for that much beef? If, instead, we fed people with this much grain, how many
pounds of human would it support? Relate to why eating meat is an expensive luxury, and why in many
countries people are vegetarians by necessity.
The next three questions refer to Figure 1 at the right.
5. Which organisms supply energy for all the others?
6.
To which trophic levels do snakes belong? Give all possibilities.
7.
If favorable weather conditions lead to an increase in the
rabbit and deer populations, what would you expect to happen
to the mountain lion population?
The next two questions pertain to organisms “A,” “B,” “C,” & “D.” Biologists know that “A” feeds on “B,” “B”
performs photosynthesis, “C” feeds on “D” and “D feeds on “A.”
8.
9.
Identify the trophic levels of all four species.
A=
B=
C=
D=
For every 100 g of “A,” how much “C” would result?
The next two questions refer to blue whales, the largest animals on Earth today!
10. An adult blue whale requires 1,010,000 kCal of krill each day in order to survive. How many pounds
of krill is this? HINT: 1 pound of krill supplies 460 kCal.
11.
Krill eat plant plankton (also called phytoplankton). How many pounds of phytoplankton are
required to produce the mass of krill in your previous answer?
The last two questions refer to tunas, which are 4th order consumers in this simplified food chain:
phytoplankton  zooplankton  small fish  medium fish  tuna
12.
Tuna is sold in 6 oz cans. How much phytoplankton resulted in 6 oz of tuna?
13.
You buy a CASE (24 cans) of tuna fish at Costco. How much phytoplankton is required for an entire
case of tuna? (For both #12 & #13, express your answers in pounds! Recall that 1 lb. = 16 oz.)