Katie Eyring
Research Lesson Plan
7/16/10
Target Concepts: Generating hypotheses, Organize and Interpret Data (Graphs)
Scientific Inquiry - B-1 The student will demonstrate an understanding of how scientific inquiry and
technological design, including mathematical analysis, can be used appropriately to
pose questions, seek answers, and develop solutions.
Indicators: B-1.1 Generate hypotheses on the basis of credible, accurate, and relevant sources of
scientific information.
Materials:
Tweezers
100 small shells/ table
Activity worksheets (Rules & worksheet)
Graph paper
Colored Pencils
Pre – MacMod
This is a graph showing a mouse population over time. The line to show the hawk population over
time is missing. Draw a line that would show the relationship between a hawk and a mouse. Explain
the relationship between the hawk and the mouse using your graph. Try and include the words 1)
predator and 2) prey in your answer.
Mouse
Introduction
The purpose of this exercise is to show the cycles of predator – prey populations over times. In this
scenario there will be a top predator (introduced later in the scenarios), a secondary predator and a prey
item. Introduce and give some background information on the animals you will be working with. For
example in this exercise blue crabs, oyster drills and oysters will be used. Blue crabs are voracious
predators that live in salt marshes along the east coast of the U.S. Atlantic oyster drills are snails that
feed on oysters and other bivalves and are found along the east coast of the U.S. Oysters are bivalves
that create reefs in salt marshes along the east coast of the U.S. Discuss how the blue crabs are the top
predator in this system, oyster drills are the secondary predator, and oysters are the prey item.
Procedure:
Predator Prey Simulations
For this activity have the students in groups of 4. They will be performing 4 - 8 trials of
predator prey simulations. Each trial will be considered a new day of feeding. Throughout each trial
there will be a new component added to account for population increase and decrease. The students
will act as “predators” (oyster drills). Shells on the desk will be the “prey” (oysters). Once introduced
to the game, the role of the top predator (blue crabs) will be given to the teacher.
Trial 1: Predator Prey simulation
Trial 2: Large predator population effect on prey populations
Trial 3: Introduction of top predator and effects (multiple runs of this trial work best)
Trial 4: Larger top predator population effects
Depending on the level of students, walk them through making a chart to collect their data over the
course of the trial. Ask them what information they will need. Draw the template on the board and
throughout the trials have each table fill in their information on their chart. In the end, the chart should
be as follows:
Trials
Oyster Population
Drill Population
Blue Crab Population
Initial population
1
2
3
4
Trial 1: Predator – prey populations
1. Introduce scenario – Predator eats prey items. Oyster drills eat oysters.
2. Hypothesize – Ask students what they think will happen to the population of oysters and the
population of drills with this scenario?
3. Activity
1. Start with 100 shells on the desk (simulating an oyster population).
2. 2 students at each table are given the role of a predator (oyster drill).
3. Have a stationary bucket in the center of the desk that cannot be moved.
4. The students will simulate eating the oysters by picking up the oyster shell and placing it
in the bucket.
5. Have the students “eat” as much as they can in a 15-30 second time trial.
6. Have the students count the number of shells left over on the desk.
7. Have the students collect their table data into their own chart.
4. Discuss their findings and have them draw and explain what happened. This can be filled out on
the “Predator Prey Simulation Worksheet”.
5. Discuss what may possibly happen to the “oyster drill” population over time. Talk about a
possible increase in “predator” population. This will be simulated in the next trial.
6. Explain that the oysters are also regenerating even if the population is decreasing. Before
beginning the next trial make sure to add 20 shells to the desk.
Trial 2: Larger population of predator
1. Introduce scenario – Over time the oyster drill (predator) population will increase.
2. Hypothesize – What will happen to the oyster population as the population of oyster drills
becomes larger?
3. Activity
1. Add 20 shells to the desk to simulate 20 new oysters being born.
2. Each student is now allowed to simulate being a predator during this time trial to show
the population of drills increasing.
3. Allow the students to “eat” as much as they can in 15-30 seconds.
4. Have the students count the number of shells on the desk.
5. Have the students collect their table data into their own chart.
4. Discuss their findings and have the students draw and explain what happened during the trial.
5. Again explain that the oyster populations are still regenerating and add 20 shells to the desk.
Trial 3: Introduction of a top predator to the system
1. Introduce scenario – Introduce the idea of a top predator in the system. In this case the top
predator will be a blue crab.
2. Hypothesize – Ask the students what will happen to the populations of oyster drills and oysters
when the blue crab is introduced to the system?
3. Activity
1. Add 20 oyster shells to the desk.
2. Each student is now allowed to use 2 hands (holding tweezers) to simulate a large
population of oyster drills.
3. The teacher will act like the top predator (blue crab). During this trial if a student is
tapped on the shoulder they must stop “feeding” and sit on their hands to simulate the
“oyster drills” dying.
4. During the 15-30 second trial tap 2 students from each table on the shoulder and have
them simulate “dying” and stop collecting shells.
5. Have the students collect their table data into their own chart.
4. Discuss their findings and have the students draw and explain what happened when a top
predator was introduced.
5. Also discuss implications for what will happen to the top predator population over time.
6. Explain oysters are still regenerating and add 20 shells to the desk.
Trial 4: Large top predator populations effects on lower levels of a food web.
1. Introduce scenario – Top predator population increase.
2. Hypothesize – what will happen to the populations of oysters and oyster drills as the population
of blue crabs becomes larger?
3. Activity
1. Add 20 shells to the desk to simulate oysters being born.
2. Allow the students to “eat” for 15- 30 seconds.
3. Of the 2 remaining students simulating being drills at each table, tap 1 on the shoulder
and have them simulate dying. This should leave 2 drills at each table.
4. After the trial ask the students to count the number of shells on the desk.
5. Have the students fill in the chart at the desk of the population sizes of each of the
animals.
4. Discuss their findings and have the students draw and explain what happened during this trial.
As a class discuss what the students findings were and walk them through how to make a graph to
show the relationships between each of the animals. Make individual graphs for the population of each
organism over time. Then in general discuss the population increases and decreases over time. Make a
graph that shows what happens to the 3 populations over time so the students can see the interaction of
each organism.
Post MacMod:
This graph shows the relationship between a sea bass population and a shrimp population over time. At
some point a shark population was introduced to the area. Draw a line to show the shark population
over time. Explain the relationship between the shark and the shrimp using your graph. Include the
words 1) top predator 2) prey 3) population.