EcologicalPyramidsVirtualLab

http://glencoe.mcgraw-hill.com/sites/dl/free/0078802849/383926/BL_02.html

Place the organisms in the correct trophiclevels to complete the pyramids for the 5 different ecosystems in the table. After you have correctly placed all the organisms fill in the data inthe tables for the pyramids ofnumbers and energy.

1. Data for Pyramid of Energy

Now you can ask yourself, "how well does the energy transfer fromone trophic level to the next?" What you want to know is how much energy is left over fromone trophic level to the next. To do this you will complete a "conversion efficiency" between eachtropic level.To do this you divide the energy at the higher energy level by the energy at the lower trophic level.This gives you a ratio that you can use for comparison, write your answer as a decimal. Completethis for all three of your ecosystems.

2. Energy conversion efficiency table

3. If you round-off your numbers above which of the following decimal numbersmost closely matches ALL
your numbers?

A. 0.23 B. 0.10 C. 0.30 D. 0.01

This exercise shows you that

% ofenergy fromthe lower level isavailable to the next level up.

With this information complete the flow chart below that shows how much energy will be found at each level for the generalize ecosystem,
(one has been done for you).

TopCarnivore (4^th consumers)
unit(s) of energy

Herbivores(1^st consumers)

Omnivores(2^nd consumers)
unitsof energy

Carnivores(3^rd consumers)
unitsof energy

Producers

1000

units ofenergy

unitsof energy

4. This exercise shows you that _____% of energy from the lower level is available to the next level up.

Producers units of energy =
Omnivores units of energy =
Carnivores units of energy =
Top carnivores units of energy =

5. Data for Pyramid of Numbers

6. Does the population size increase or decrease at higher trophic levels in the pyramid of numbers for all of your ecosystems? Explain your answer.

7. 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?

8. What would happen to an ecosystem if the decomposers disappeared?

9. Could there be a food chain without herbivores and carnivores?

10. Compare and contrast two of the ecosystems you studied. How is the energy conversion efficiency similar or different?