Virtual Ecosystems—How Energy Moves Through Ecosystems
1. Open the link titled “Model Ecosystems” from Chapter 3 on the Documents and links page
of our website.
2.
To begin, open the FIELD GUIDE by clicking the book icon. Read the introduction
portion of the Field Guide and match the words to the appropriate definition below.
____1. A community of living organisms interacting with the environment
____2. Organisms that use the sun’s energy to produce their own nutrients
____3. Organisms that can’t make their own food and rely eating other organisms
____4. The product made by autotrophs through photosynthesis
____5. Another name for autotrophs
____6. The source of energy that fuels most ecosystems
____7. A heterotroph that eats only plants
____8. Carnivores that eat on herbivores
____9. Carnivores that eat other carnivores
____10. Each step in a food chain
____11. The total mass of all living organisms in an ecosystem
a. biomass
b. producers
c. herbivore
d. ecosystem
e. 3rd order het.
f. tropic level
g. heterotroph
h. autotrophs
i. 2nd order
heterotrophs
j. sun
k. glucose
3. For each of the five ecosystems:
a. Read the information about the ecosystem in the FIELD GUIDE
b. Select the ecosystem type that you would like from the pull down menu at the
top.
c. Click and drag the various organisms to their correct locations within the
different trophic levels of the pyramid.
d. Once you have moved all of the organisms click the “Check” button and fix
any incorrect choices.
e. Clicking on the “Pyramid of Energy” will reveal how much energy is
available at each trophic level.
f. Clicking on the “Pyramid of Numbers” will show the number of organisms at
each trophic level within this type of ecosystem.
g. Fill in all of the information from these pyramids on the data table on in this
packet. You don’t need to fill in every organism at every level, select a few
sample organisms.
4. Analyze this data by calculating the energy conversion efficiency (ECE) for each trophic
level for each of the five ecosystems and record the results.
The energy conversion efficiency is calculated by dividing the energy at the higher
trophic level by the energy at the lower level to obtain a ratio. This ratio tells you how
much of the available energy in the lower tropic level made it to the next level up.
Enter the value as a decimal number. Round your answer to the nearest hundredths. You
will not have an ECE for the first column “producers.”
5. When you are finished analyzing the ecosystem, click the “Reset” button and select another
ecosystem from the pull down menu and repeat the above procedures.
Ecosystem
Type
Deciduous
Forest
Producers
Organisms present:
First Order
Heterotrophs
Organisms present:
Second Order
Heterotrophs
Organisms present:
Third Order
Heterotrophs
Organisms present:
Number of
Organisms in this
tropic level:______
Number of Organisms
in this tropic
level:______
Number of Organisms
in this tropic
level:______
Number of Organisms
in this tropic
level:______
Energy in level:_____
Energy in level:_____
Energy in level:_____
that move up to this level
(ECE)_____
% of available Energy
that move up to this level
(ECE)_____
% of available Energy
that move up to this level
(ECE)_____
Organisms present:
Organisms present:
Organisms present:
Organisms present:
Number of
Organisms in this
tropic level:______
Number of Organisms
in this tropic
level:______
Number of Organisms
in this tropic
level:______
Number of Organisms
in this tropic
level:______
Energy in level:_____
Energy in level:_____
Energy in level:_____
% of available Energy
that move up to this level
(ECE)_____
% of available Energy
that move up to this level
(ECE)_____
% of available Energy
that move up to this level
(ECE)_____
Organisms present:
Organisms present:
Organisms present:
Organisms present:
Number of
Organisms in this
tropic level:______
Number of Organisms
in this tropic
level:______
Number of Organisms
in this tropic
level:______
Number of Organisms
in this tropic
level:______
Energy in level:_____
Energy in level:_____
Energy in level:_____
% of available Energy
that move up to this level
(ECE)_____
% of available Energy
that move up to this level
(ECE)_____
% of available Energy
that move up to this level
(ECE)_____
Energy available in
% of available Energy
level: ______
Hot Desert
Energy available in
level: ______
Grassland
Energy available in
level: ______
Antarctic
Ocean
Shore
Organisms present:
Organisms present:
Organisms present:
Organisms present:
Number of
Organisms in this
tropic level:______
Number of Organisms
in this tropic
level:______
Number of Organisms
in this tropic
level:______
Number of Organisms
in this tropic
level:______
Energy in level:_____
Energy in level:_____
Energy in level:_____
% of available Energy
that move up to this level
(ECE)_____
% of available Energy
that move up to this level
(ECE)_____
% of available Energy
that move up to this level
(ECE)_____
Organisms present:
Organisms present:
Organisms present:
Organisms present:
Number of
Organisms in this
tropic level:______
Number of Organisms
in this tropic
level:______
Number of Organisms
in this tropic
level:______
Number of Organisms
in this tropic
level:______
Energy in level:_____
Energy in level:_____
Energy in level:_____
% of available Energy
that move up to this level
(ECE)_____
% of available Energy
that move up to this level
(ECE)_____
% of available Energy
that move up to this level
(ECE)_____
Energy available in
level: ______
Freshwater
Lake
Energy available in
level: ______
ECE= energy conversion efficiency ratio
Post-laboratory Questions:
1. You calculated an “ECE” for each tropic level. Exactly what does this number
represent? _________________________________________________________
__________________________________________________________________
2. Organisms that directly use energy from the sun to make their own food are called:
a. Autotrophs
b. Hetertrophs
c. Carnivores
d. Decomposers
3. Which of the following illustrates the correct ordering of trophic levels?
a. Decomposerscarnivoresautotrophsherbivores
b. Herbivoresautotrophscarnivoresdecomposers
c. Autotrophsherbivorescarnivoresdecomposers
d. None of the above
4. The efficiency of energy transfer from a lower trophic level to the next highest level is
roughly:
If energy cannot be created or destroyed, Where does the energy go that does
a. 1%
not make it to the next tropic level up? _______________________________
b. 5%
______________________________________________________________
c. 10%
d. 50%
______________________________________________________________
______________________________________________________________
5. In aquatic ecosystems, biomass is the smallest at which trophic level? THIS
ANSWER IS IN THE FIELD GUIDE!!!
a. Autotrophs
How is this different from the other terrestrial ecosystems? ________
b. Herbivores
_________________________________________________________
c. Carnivores
_________________________________________________________
Why is the biomass distributed this way?________________________
_________________________________________________________
Answer the following in complete sentences:
6. Suggest reasons why the information represented in the pyramid of numbers of animals of one
of the ecosystems you studied may not truly represent that ecosystem.
______________________________________________________________________________
______________________________________________________________________________
7. Compare and contrast two of the forest and desert ecosystems. How is the energy conversion
efficiency similar or different?
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
8. Does the population size increase or decrease at higher trophic levels in the pyramid of
numbers of an ecosystem consisting of a tree, insects (that are herbivores) and birds feeding on
the insects? Why?
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
9. Explain how energy flows through an ecosystem. Does it flow in one direction or is it
recycled. How is this different from matter? Does matter flow through or is it recycled in an
ecosystem? You are welcome to use internet research to help you construct your answer!
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