BIO 103 Predation and Prey Modeling Lab – Assignment Solution
Predation and prey modeling lab Introduction: In 1970, the deer population of an island forest preserve was about 2000 animals. Although the island had excellent vegetation for feeding, the food supply had limits. Therefore, the forest management staff worried that overgrazing might lead to mass starvation of the deer. Since the area was too isolated for hunters, the wildlife service decided to bring in natural predators to control the deer population. This is an example of a predator/prey relationship. It was hoped that natural predation would keep the deer population from becoming too large and increase the deer health, as the deer population approached the carrying capacity of the island. Carrying capacity is the maximum number of organisms that can survive in a habitat without impacting other organisms in that habitat. Limits on the carrying capacity include food, water, cover, prey and predator species. In 1971, ten wolves were flown into the island. The results of this program are shown in the following table. The population change is the number of deer born minus the number of deer that died during that year. The herd population started at 2000 when this study began. • Calculate the number of deaths (predation + starvation). • To determine the deer population change, subtract the number of deaths from births (births – deaths), this can be a positive number, indicating growth, or a negative number which indicates a population decline. • Calculate the deer population by adding/subtracting the population change from the population the year before • The year 1971 has been completed for you as an example. Year Wolf population Deer births Predation Starvation Number of deer deaths Deer population change Deer population 1970 Starting population 2000 1971 10 800 400 100 400+100=500 800- 500=300 2000+300=2300 1972 12 920 480 240 1973 16 1000 640 500 1974 22 944 880 180 1975 28 996 1120 26 1976 24 836 960 2 1977 21 788 840 0 1978 18 766 720 0 1979 19 780 760 0 1980 19 790 760 0
Graph the wolf vs. deer populations. You can do this in Excel or draw the graphs. You should use a bar graph to model the population. (Hint: you can copy/paste the table above into Excel).
You can include both deer and wolves on one graph OR make separate graphs for each.
Here is an example:
Predation and Prey Modeling
Analysis: Answer the following questions using complete sentences.
1. Describe what happened to the deer population between 1971 and 1980.
2. When was the wolf population the highest? What happens to the deer population when the wolf population increases?
3. What do you think would have happened to the deer on the island had wolves NOT been introduced?
4. What do you think would have happened to the ecosystem on the island if wolves had NOT been introduced?
5. While the deer are native to the island, the wolves are not native. What do you think the possible impacts of the wolves might be on the island ecosystem?
6. Hypothesize what might happen if a non-native prey species such as a rabbit was introduced to the island. What would happen to the deer? What about the wolves? (Hint: Larger rabbits can be prey for wolves).
Predation and Prey Modeling
Adaption from: Deer: Predation or Starvation, www.biologycorner.com
Predation and Prey Modeling
- Predation and prey modeling lab
