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Introduction:
Ecosystems consist of organisms that interact with each other. Interactions can consist of predator and
prey relationships. Predator eats prey for survival. Over time, this relationship can lead to a change in
the characteristic of the populations of each organism. Our goal for this investigation is to find out how
a bug population’s characteristics change depending on differences in predation (a hunting predator vs.
a sit-n-wait predator). The guiding question for this investigation is “how do the characteristics of a bug
population change in response to different types of predators.”
Method:
The method we used to gather our data was to use a computer simulation of an ecosystem including a
bug population (which consists of bugs who move at different speeds) and a predator. In testing two
different types of predators (a hunter vs. a sit-n-wait predator), we started the simulation with a
population of 60 bugs with 10 of each different speed. Every minute we collected quantitative data that
consisted of the amount (population) of each of the different bug speeds. We then graphed the
population over time (2 graphs) that showed how the speed of the bugs changed over 6 minutes.
Argument
Claim:
Our claim is that slower bugs are eradicated from the population with a “hunting” predator because
hunters can more efficiently catch slower bugs, and that faster bugs are eradicated from the population
with a “sit-n-wait” predator because the faster bugs will enter the predator’s area at a fast rate.
Evidence:
30
Number of Bugs
25
20
Purple
Blue
15
Green
Yellow
10
Orange
Red
5
0
0
1
2
3
Time (minutes)
Figure 1 shows a population with a hunting predator.
4
5
6
45
40
Number of Bugs
35
30
Purple
25
Blue
20
Green
Yellow
15
Orange
10
Red
5
0
0
1
2
3
4
5
6
Time (minutes)
Figure 2 shows a population with a sit-n-wait predator.
Our graphs indicate that slower bugs are eradicated while faster bugs increase with a hunting predator
and the opposite effect happens with a sit-n-wait predator. While the other groups collected different
data (change in speed of the bug population over time), our evidence supports the same claim. We also
found that hunting predators can gather more bugs in a time period than sit-n-wait (hunting for 1
minute = 197 bugs vs. sit-n-wait for 1 minute = 41 bugs). Hunting predators in this ecosystem will be
more successful.
Justification:
Predation leads to evolution which is indicated by a change in characteristics in the bug population. The
change in characteristics of the bug population can change in different ways depending on the type of
predation happening in that specific ecosystem.