Name: _____________________________________________ Date:_________ period:_____
Unit 3 Ecology
Energy Transfer (p.73-78)
Directions: For each of the following, write “I” if the pea harvest would increase, or “D” if the pea harvest would
decrease.
1. _____ A severe winter kills many birds in the area.
2. _____The aphid population increases.
3. _____The spider population doubles.
4. _____The bird population increases.
5. _____More ladybugs are introduced to the garden.
6. In the food chain above, which organism is the producer?_________________
7. Which organism in the primary consumer?_________________
8. Which organism is the secondary consumer?________________
9. Where do the peas that are being harvested get their energy?
10. Suppose a pesticide (kills insects that destroy crops) such as DDT was sprayed on pea plants. Why is it that the
bird has the highest concentration of DDT in its body?
Directions: Refer to the energy pyramid to answer the questions below.
11. Create a food chain using some of the organisms listed in the
ecological pyramid.
12. What is the top consumer in this ecological pyramid?
13. Why are there much few top consumers compared to other organisms in lower trophic levels?
14. A. Only about 10 percent of the energy taken in by an organism is stored in its body. What happens to the rest of
the energy?
B. If your first trophic level (aka your producers) contained 4,500,000 calories of energy, how much energy
would you expect in top trophic level? (Show your math!)
15. If a shortage of food were a national problem, would it be wiser to use your last acre of land to grown
grains/vegetables or graze cattle? Explain in terms of energy use.
Name: _____________________________________________ Date:_________ period:_____
Unit 3 Ecology
Energy Transfer (p.73-78)
Directions: For each of the following, write “I” if the pea harvest would increase, or “D” if the pea harvest would
decrease.
1. _____ A severe winter kills many birds in the area. Decrease
2. _____The aphid population increases. Decrease
3. _____The spider population doubles. Decrease
4. _____The bird population increases. Increase
5. _____More ladybugs are introduced to the garden. Increase
6. In the food chain above, which organism is the producer?_________________ Pea
7. Which organism in the primary consumer?_________________ Aphid
8. Which organism is the secondary consumer?________________ Ladybug
9. Where do the peas that are being harvested get their energy?
The sun
10. Suppose a pesticide such as DDT was sprayed on pea plants. Why is it that the bird has the highest concentration
of DDT in its body? DDT accumulates in the tissues of consumers. Since aphids eat peas, the DDT will begin to
accumulate in the tissue of aphids as it continues to eat them. Ladybugs, which each multiple aphids to survive,
will then be consuming even more DDT increasing the concentration of this chemical in their tissue. Etc.
Directions: Refer to the energy pyramid to answer the questions below.
11. Create a food chain using some of the organisms listed in the
ecological pyramid.
Ex. Grass  rabbit  snake  hawk
(Arrows should point in the direction the energy is flowing!)
12. What is the top consumer in this ecological pyramid?
The hawk
13. Why are there much few top consumers compared to other organisms in lower trophic levels?
Since top consumers have to eat more to get enough energy to survive the food web can’t sustain too many of
them. If there were too many top consumers they would starve.
14. A. Only about 10 percent of the energy taken in by an organism is stored in its body. What happens to the rest of
the energy? It is lost as heat or used up by the organism during life processes such as reproduction,
growth/development, metabolic processes, etc.
B. If your first trophic level (aka your producers) contained 4,500,000 calories of energy, how much energy
would you expect in top trophic level? (Show your math!) Since only 10% of all energy is passed between
consumers, and the top consumer is the third consumer in the ecological pyramid, it will only have .1% of the
original energy.
Original x Amt of Energy Passed on as a Decimal
4,500,000 x .001 = 4,500 calories
15. If a shortage of food were a national problem, would it be wiser to use your last acre of land to grown
grains/vegetables or graze cattle? Explain in terms of energy use.
It would be wiser to grown grains/vegetables because they will be able to yield the most energy to consumers
for the least cost since they make their own food.