Predator-Prey Simulation Activity
Observing the relationship between predators and prey is both fascinating and complex.
Previously, ecologists had thought that the relationship between predators and prey was
both simple and direct: the predator fed upon the prey thus keeping the prey’s
population in check while maintaining and increasing its own population. We now know
that the relationship between predators and prey is not so simple and that many other
factors affect population swings in an ecosystem. In addition, the direction of cause and
effect is more subtle than it first appears. These are some of the things that you should
think about while doing this activity and answering the questions that follow. Our
scenario takes place in the ocean off South America between two species: King Penguins
and Orcas.
Graphing:
1. First, graph the Initial Prey vs. Generation (one color)
2. On the same graph, graph the Initial Predators vs. Generation (another color).
3. Be sure to include a key on your graph to let the reader know which line is the
prey and which line is the predators.
Discussion Questions:
For all of the questions below, answer in full sentences and be sure to explain your answers fully
and completely. Remember that this is a LAB REPORT! The more in-depth your answers are and
the more you show your knowledge of the subject, the more points you will get! All answers
should be done on another piece of paper. They can be typed. If I cannot read your writing, I
cannot give you a grade and your report will end up as a zero.
1. Look at your graph, what patterns do you notice? Explain and cite evidence. This
should be a paragraph and should address the following:
a. What factor appears to determine the size of the orca population at any
given time?
b. What factor appears to control the penguin population?
c. Does a peak in the orca population come at the same time as or after a
peak in the penguin population? What is the explanation for this?
2. Summarize this predator-prey relationship in terms of the greater ecosystem of
which it is a part. In your paragraph answer, address the following:
a. What other factors could be controlling the population of the penguins
besides the orcas?
b. What would happen to the orca population if the penguins were
eliminated from the ecosystem due to a viral disease?
c. Is predation a density-dependent or density-independent factor? Explain
d. Is it possible for a species to be both predator and prey? Explain.
In your answers, be sure to proof-read your answers to make sure they “flow” and sound
grammatically correct. Also, be sure to use key vocabulary from this unit as you address
the questions. Cite data from your lab as evidence and justify that evidence.