Ecological Pyramids
Please do all work on a separate sheet to be turned in.
1.
Go online and look up a definition for ecological pyramid. Describe the definition below. Then
describe how the second law of thermodynamics relates to an ecological pyramid.
2. One way to represent an ecological pyramid is by a pyramid of numbers.
a. What is a pyramid of numbers?
b. If you were asked to assemble a pyramid of numbers for an ecological community such as an old
growth forest, how would you go about doing this? Show an example of what such a pyramid
might look like. Include the units that are typically used to determine the size of each trophic
level.
3. Another way to represent an ecological pyramid is by a pyramid of biomass.
a. What is a pyramid of biomass?
b. If you were asked to assemble a pyramid of biomass for an ecological community such as an old
growth forest, how would you go about doing this? Show an example of what such a pyramid
might look like. Include the units that are typically used to determine the size of each trophic
level.
4. A third way to represent an ecological pyramid is by a pyramid of productivity.
a. What is a pyramid of productivity?
b. If you were asked to assemble a pyramid of productivity for an ecological community such as an
old growth forest, how would you go about doing this? Show an example of what such a
pyramid might look like. Include the units that are typically used to determine the size of each
trophic level.
5. Of these three (numbers, biomass, productivity), which gives the most realistic picture of the flow of
energy in an ecosystem? Explain your answer please. Give specific drawbacks that are inherent in the
two types of ecological pyramids that you do not think are the most realistic. In other words, what are
some examples of ecological communities that do not generate a pyramid shape when tabulated along
the lines of the two options that you think are not as realistic?
6. Mark off a 2meter x 2meter area of your yard. Collect and tabulate data that will allow you to construct
a pyramid of numbers for this area. After tabulating the data, then construct/diagram the pyramid.
Remember, primary producers are always located on the first (bottom) trophic level. Herbivores are
next, and carnivores above that. Did your diagram actually end up looking like a pyramid? If it did not,
please explain why it deviates from the ideal situation that theory would dictate. Please bring your data
and diagram to class ___________________.