University of California Irvine Predator Prey Simulation Questions

Predator-prey simulation: What happens to coyotes whenthey eat all of their prey?
LS 3041 Course Objectives
#3: Students will be able to identify and describe major theories and methods in the natural
sciences (including limitations) to show an appreciation of and critical perspective on scientific
knowledge.
#5 Students will be able to apply the epistemology of science and major methodologies in the
natural sciences to the phenomena they study and knowledge they create.
Lesson Objectives (what students will know or be able to do):
● Students will simulate the predator-prey relationship between coyotes and mice in natural
ecosystems using cut outs.
● They will record data throughout the simulation and use it to properly graph (label axes
w/ descriptive titles, scale the graphs, and title the graphs descriptively) a predator-prey
curve in Excel.
● They will interpret the data in their graphs and make inferences about real-life predatorprey relationships
.
Other possible connections to extend to Common Core ELA and Math Standards:
● They will write lab reports based on their predator-prey models
● They will present their findings to the class in the form of a scientific talk
● Teachers may also connect the activity to both non-fiction and fiction texts related to the
topic of predator-prey interactions, e.g. Time Magazine article, “America’s Pest Problem”
Description of activity:
o Materials: masking tape, Internet access, Excel or other graphing software, cut
outs of mice and coyotes, pencils, paper
● Anticipatory Set: The teacher will have already introduced the concept of food webs and
predator-prey cycles to the students, showing them an example of a predator-prey
relationship in nature (lynx and rabbits). The teacher can connect the importance of these
relationships to the students’ lives by discussing the sea otter-urchin-kelp food web,
whereby the removal of the top predator and keystone species, the otter, leads to an
overpopulation of urchins, which destroy kelp forests. Kelp is utilized to make all sorts
of goods (like ice cream, toothpaste, dog food, etc). Teachers may also want to begin
with the Time Magazine article, “America’s Pest Problem,”
Procedure:
Throughout the procedure the teacher will walk around the room answering questions and
providing guidance, when needed. This is a student-led activity so the teacher’s role is mainly
guidance.1 Once the activity portion is completed, the teacher will explain to students, using
sample data, how to construct graphs in Excel. Students can produce these graphs in class (if
there is adequate access to technology) or as a homework assignment.2
1. Each lab group will need to set its own parameters for the simulation as follows: How
many mice are in the field under initial conditions? What is the minimum number of
mice a coyote needs to eat to survive and reproduce? How many mice does a coyote need
to eat above the minimum to produce 2 or more pups for the next generation?
2. Remember the relationship between predator and prey is usually cyclical and their
corresponding numbers will rise and fall in some pattern. You will probably need at least
15 iterations of the simulation to see if you have a pattern. It may take some trial and
error to determine the proper rules for your simulation to demonstrate a pattern.
3. Using masking tape, mark off a field on the floor. You should try different size fields
before you start officially recording data in order to ensure that the parameters you
selected “work” in your selected field size.
4. Record all of your group parameters.
5. Drop the papers representing the starting number of mice into the square. They should
fall randomly inside the borders of the field. Experimentation will determine from how
high the papers need to be dropped to give consistent random falls within the square.
6. Once your mice are distributed, drop 1 preying coyote into the field. For the coyote to
survive and reproduce, it must fall directly on the number of mice determined by your
parameters. Take the eaten mice out of the square. Assume that the remaining mice get
to reproduce by doubling their numbers. This ends one generation. Be sure you are
recording your data in a spreadsheet or in the table provided below. To graph them later,
you will need to use Excel.
7. The next generation is represented by the new number of mice and they are preyed on by
the number of surviving coyotes. If no coyote survives a generation, start again with one
coyote. If all of the mice are eaten, start again with the same number as in the first round.
8. Record the number of surviving mice and coyotes after each round in your data table.
9. Repeat this process for at least 15 iterations to see if you have a predictable pattern
developing. If your data seem chaotic, rethink your conditions, make parameter
adjustments, and continue. If you adjust your parameters, be sure to write down the new
ones and start the simulation again with Trial #1.
10. As the coyote numbers increase, remove the mice eaten by each coyote in that generation.
As one coyote eats mice it is harder for the following animals to hunt successfully. In
this way, the simulation also models the effectiveness of superior hunters and how natural
selection (the theory of evolution) operates. Record the total population of each at the
end of the generation.
1
At the middle school level, the teacher may need to offer more guidance with helping students plan field size and
parameters for coyote survival and reproduction.
2
Depending on the students’ grade level and access to technology, teachers may have students construct their
graphs by hand.
11. When your model seems to be producing a cyclical pattern, complete at least 15 iterations
and graph the data in Excel. Your instructor will show you how to do this.3
Mice starting: 10
mice multiplies by half every two rounds
need 1 to survive
eat 4 produce 2 more pups
Data Table: Number of coyotes and mice in each iteration of simulation
Coyotes
Mice
1
1
10 – 2 = 8
2
1
8 + 4 = 12
3
1
12 – 1 = 11
4
1
11 + 5 = 16
5
1
16 – 3 = 13
6
1
13 + 7 = 20
7
3
20 – 5 = 15
8
5
15 + 7 = 22
9
5
22 – 11 = 11
10
9
11 + 5 = 16
11
9
16 – 10 = 6
12
13
6+3=9
13
13
9-7=2
14
6+2
2+1=3
15
8
3-3=0
16
5
0
17
18
19
20
21
22
23
24
25
How will you assess whether students have met the objective?
Formative Assessment
3
When the students construct the graphs, they should put the simulation number on the X axis (to simulate the time
of year), the mice on the primary Y axis (which the will scale differently than the coyotes due to a large difference in
population size) and coyotes on the secondary Y axis. Be sure to have them title their graphs and to label all the
axes. The teacher will probably want to use a data set she already has to walk students through the process as they
use their own data, particularly with younger students.
● Throughout the activity, the teacher will wander around the room to see if the students
are getting “good” data they can use to create a graph. If the students are not getting
good data, the teacher will advise them, through questioning, on how to change the
parameters and size of their habitat to yield better results.
● Before graphs are submitted, the teacher will give students an opportunity to share their
graphs and receive feedback.
Summative Assessment (This is what students in your classroom might do)
● Students will submit their graphs for teacher viewing along with answers to a series of
discussion questions related to the activity and real-life predator-prey relationships (See
below). These assessments will allow the teacher to gauge whether students learned the
requisite graphing skills and how deeply the students were able to explain their results
(higher level Bloom’s skills and thinking)
● The teacher may also wish to have students write a lab report or do an oral presentation
(scientific talk)
● The activity can also be extended to have students do research projects on other real-life
predator-prey relations or to connect what they have read to fiction or nonfiction works
(e.g. Aldo Leopold’s A Sand County Almanac). These extensions will allow the
simulation to teach a wide variety of the NGSS, ELA, and Math standards.
Assessment Questions (Answer these! This is what you should do!)
1. Thomas Kuhn contends that observations are theory laden, which means that they depend
on a body of theoretical assumptions through which they are perceived and
conceptualized. Discuss how the theory of evolution (natural selection) guides the ways
in which you interpret your data (~150 words).
2. Throughout this simulation, do you think that you were able to take an objective stance
(“view from nowhere”)? How might your observations during this activity be limited
(See the Carey reading). (~100 words. )
3. How might epistemic (cognitive) values influence this simulation? How might contextual
(noncognitive values) influence this simulation? Before you answer this, review the
difference between epistemic and contextual values from the epistemology reading and
cite that reading in your answer (~100 words).
4. Which scientific practices (from the NGSS Framework) do you think you engaged in
this simulation? Please explain why you think you engaged in these practices? (~150
words)
5. What do you predict would happen to your results if your system were disturbed by some
unforeseen, outside forces? For example, what would happen if some coyotes died of
disease or were driven off by large predators or hit by cars? (How does this question
engage you in the practice of science)? (~150 words)
Evaluation
For full credit, turn in:
● A table with all of your simulation parameters (include any adjustments you made if your
initial conditions didn’t work)
● A table with the results of all of your trials
● A copy of your properly labeled graph
● Answers to the questions above