Download Modeling Ecosystem Energy Flow – Virtual Lab

Name: ________________________________________ Date: ____________________________ Period: ___________
Modeling Ecosystem Energy Flow – Virtual Lab
Go to the ecosystem website – http://www.mhhe.com/biosci/genbio/virtual_labs/BL_02/BL_02.html –
an introduction and hints for how to use the program are written on the left-hand side.
1. Select your assigned ecosystem from the pulldown bar at the top
Deciduous Forest
Hot Desert
Antartic Ocean Shore
Grassland
Freshwater Lake
2. Select the icon (blue button) next to each animal on the field notes list, and drag and drop them to the
appropriate trophic level in the ecosystem pyramid.
3. Click the check button – when all animals are placed correctly, their names will be replaced with
pictures and the number of each kind.
4. Record this information in the data table below.
5. Click on the pyramid of numbers button to determine the total number of organisms at each trophic
level – record in the data table.
6. Click on the pyramid of energy button to display numbers indicating the amounts of energy at each
level – record in the data table.
7. Calculate the conversion efficiency for each trophic level – record in the data table.
*** The energy conversion efficiency is calculated by diving the energy at the higher trophic level
(smaller number) by the energy at the lower trophic level (larger number) to obtain a ratio – it
will be a decimal number.
Producers
1st Order
Heterotrophs
2nd Order
Heterotrophs
3rd Order
Heterotrophs
Organism
Name/Number of
Organism
Total number of
organisms at this
trophic level
Energy at this
trophic level
Conversion
efficiency
Conclusion Questions – to be completed in your notebook after discussing results with your group.
1. 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.
2. According to your data, what is the ratio of third-order consumers to producers? Explain your answer.
3. Compare and contrast two of the ecosystems you studied. How is the energy conversion efficiency
similar or different?
4. 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? Explain
your answer.
5. What might happen to an ecological pyramid of numbers in a forest ecosystem if most of the deer were
killed due to hunting by people and disease?
6. What would happen to an ecosystem if the decomposers disappeared?
7. Could there be a food chain without herbivores and carnivores?