High School Biology Unit 2
1
Human Impact on Ecosystems and Population Dynamics
Science
High School
Common Assignment 1
Population Dynamics Lab Report
Table of Contents
1. Teacher Materials
a. Analyzing Human Impacts on Population Dynamics—Teacher Instructions
2. Student Materials
a. Analyzing Human Impacts on Population Dynamics—Student Instructions
Human Impact on Ecosystems and Population Dynamics: Common Assignment 1
Population Dynamics Lab Report
High School Biology Unit 2
2
Analyzing Human Impacts on Population Dynamics
Introduction
This lab is designed to give students exposure to the effects that indirect/direct human impact has on biodiversity.
Students will be working in groups to investigate the results of different impacts and recording/analyzing data.
Previous Knowledge
Before this lab, the following vocabulary terms should be introduced:
• Biodiversity (species diversity, genetic
diversity)
• Keystone species
• Invasive species
• Population density
• Cover (habitat)
• Mitigate
• Predator-prey interaction
• Logistic growth
• Exponential growth
Group Structure
Students should be split into groups no smaller than four, no greater than five.
• Three students will be the mice who are gathering food.
• One to two student(s) will be recording data.
Material Preparation
Each group will need the following:
• Plastic cup (optional—for collecting beans)
• String
• Meter sticks/rulers
• Tweezers (optional)
• Four plot markers (skewers)
• Lentils/split peas
• White beans
• Stopwatch
• Calculator
Before the Lab:
• Prepare plastic bags of colored beans to make material distribution easier.
• Each group will need one full bag of beans that has both colors (green and white).
•
Although a specific number of beans is not required, make sure the amount in each bag is plentiful to
account for the multiple students who will be gathering food.
Human Impact on Ecosystems and Population Dynamics: Common Assignment 1
Population Dynamics Lab Report
High School Biology Unit 2
3
Procedure
• Students will begin by gathering their materials, then measuring a two-meter by two-meter plot in the
lawn. This area represents their ecosystem and will be marked with the yarn and plot markers provided.
• Beans (of both colors) will be spread throughout the ecosystem. Make sure the beans are distributed
through all parts of the plot, not just poured in one particular spot.
• Three team members will gather food (beans) for a full minute for each scenario.
• At the end of the minute, beans will be counted and recorded in the data tables provided. Each scenario
has its own data table.
• Once the bean numbers are recorded, the students will use the following food calculations to determine
the population numbers for the mice and hawks:
a. three beans feed one mouse
b. four mice feed one hawk
• Once the calculations are complete, students will sprinkle the collected beans back into the ecosystem.
This will happen each time you are finished gathering food to represent reproduction.
• Different interactions occur for each scenario, all of which are caused by direct and indirect human
impact. Descriptions are provided in the lab for each event.
a. Scenario 1—Normal conditions: Nothing changes
b. Scenario 2—Disease introduction: All the food gathering mice are sick except for one
c. Scenario 3—Invasive species (worm) introduction: Only green beans can be gathered, the white
beans have been eaten by the invasive species.
d. Scenario 4—Predator number increase: New food calculations based on food availability; worms
still present so only green beans can be gathered.
e. Six beans feed one mouse
f. Two mice feed one hawk
g.
Scenario 5 – Land development: Ecosystem (and therefore the space in which students are
allowed to collect food) is decreased in size by half; worms still present so only green beans can be
gathered; continue to use food calculations from scenario 4.
Example completed data table:
No. of Beans
Collected
No. of Mice
(3 beans = 1
mouse)
No. of Hawks
(4 mice = 1
hawk)
Total No. of
Organisms
(community)
Area (m²)
Total Mouse
Population
Density
Total Hawk
Population
Density
24
8
2
34
4 m²
2
0.5
Post Lab Discussion Points
• The range of human impact on population dynamics (both direct and indirect)
• Impact of invasive species
• Food equation for population numbers—accuracy
• Population requirements—how many organisms required for reproduction and growth?
• Bottleneck effect
• Lab error and correction/prevention
• Human mitigation (reducing impact) and unexpected consequences
Human Impact on Ecosystems and Population Dynamics: Common Assignment 1
Population Dynamics Lab Report
High School Biology Unit 2
4
Grading
Total lab value: 40 points
Pre-Lab Questions
1. 1 point for hypothesis
2. 1 point for identification of producers/consumers (all or none)
3. 2 points total for pyramid
a. 1 point for correct placement in pyramid (based on answer to question 2)
b. 1 point for correct math
Data Analysis
4. 5 points total
a. 1 point for title
b. 1 point each (2 points total) for each axis label with units and scale
c. 1 point for correctly plotted data
d. 1 point for correct graph (bar graph)
5. 4 points total
a. 2 points for each justification with data
i. 1 point each for minimal justification
ii. 2 points each for thorough justification
6. 3 points total
a. 1 point for stating whether hypothesis was accepted/rejected
b. 2 points for justification
i. 1 point for minimal justification
ii. 2 point for thorough justification
Drawing Conclusions
7. 3 points total
a. 1 point for explanation
b. 2 points for solution
i. 1 point for reasonable solution
ii. 2 points for detailed solution
8. 2 points total
a. 1 point each for sources of error with explanation
Application
9. 1 point
10. 1 point
11. 1 point
12. 2 points total
a. 1 point for correct identification
b. 1 point for reasonable justification
13. 4 points total
a. 1 point each for minimal explanation
b. 2 points each for thorough explanation
Data Tables
• 2 points each—10 points total
o 1 point for a correctly filled in data table
o 1 point for accurate units and calculations
Human Impact on Ecosystems and Population Dynamics: Common Assignment 1
Population Dynamics Lab Report
High School Biology Unit 2
5
Analyzing Human Impacts on Population Dynamics
Outdoor Lab Activity—Biology
Introduction
The populations of various organisms in an ecosystem can be impacted both directly and indirectly by
human interaction. Four examples of human impact on population dynamics that will be analyzed in this
lab include: (1) accidental introduction of disease, (2) accidental introduction of invasive species, (3)
changes in predator-prey relationship, and (4) habitat loss.
An ecosystem is home to many species, and within an ecosystem there are various food chains. In this
lab, your group will be acting as mice, working to gather food for your mouse population back at the
nest. Your population will experience various changes that affect not only your population of mice, but
also other organism populations in your area. You will each be given an area that will serve as your
ecosystem. Once you have collected food and fed your population, the hawks will feed on your growing
population of mice.
For your ecosystem, this is how organisms are fed:
Three beans will feed one mouse
Four mice will feed one hawk
Pre-Lab Questions
1. Based on the introduction given above, develop a hypothesis that explains the relationship of
population dynamics to direct/indirect human impact.
Human Impact on Ecosystems and Population Dynamics: Common Assignment 1
Population Dynamics Lab Report
High School Biology Unit 2
6
2. Based on the organisms described in the lab, identify the producers, primary consumers, and
secondary consumers.
a. Producers =
b. Primary consumers =
c. Secondary consumers =
3. Using your answers from question 2, start with 1,000 J at the first trophic level and construct an
energy pyramid with the correct energy quantities at each level.
Materials
Each group will need the following:
• Plastic cup
• String
• Meter sticks/rulers
• Four plot markers (skewers)
• Tweezers (optional)
• Lentils/split peas
• White beans
• Stopwatch
• Calculator
Human Impact on Ecosystems and Population Dynamics: Common Assignment 1
Population Dynamics Lab Report
High School Biology Unit 2
7
Procedure
Scenario 1—Normal Conditions
• Measure out a two-meter by two-meter plot of grass on the lawn. Mark your plot with the yarn
provided. This area is your ecosystem!
• Spread your beans throughout your plot of land.
• Three team members will be gathering beans using their hands for one minute. Each “mouse”
can only pick up one bean at a time.
• After one minute is up, count the total number of beans collected and record this number in the
data chart below.
1
No. of Beans
Collected
No. of Mice
(3 beans = 1
mouse)
No. of
Hawks
(4 mice = 1
hawk)
Total No. of
Organisms
(community)
Area
Total
Mouse
Population
Density
Total Hawk
Population
Density
Group
Trial
Class
Average
• Using the number of beans recorded in the data table above, calculate the number of mice,
hawks, and total number of organisms. When calculating, round down to the nearest whole
number. Do not worry about population density just yet, you will calculate this later!
• Sprinkle the beans back into your ecosystem. This will happen each time you are finished
gathering food, thereby representing reproduction of your bean plants each year.
Scenario 2—Disease Conditions
Oh, no! A group of local hikers have recently returned from a cross-country trip and brought back some
unexpected hitchhikers on their boots—a fungus that makes many of your mice too sick to gather food
for your population. Therefore, only one mouse is left to do all the collecting.
• One person in the group will collect beans for another full minute.
• After one minute is up, count the beans collected and record this number in the data chart
below. Using this number of beans, calculate the number of mice, hawks, and total number of
organisms.
• Sprinkle these beans back into your ecosystem.
2
No. of Beans
Collected
No. of Mice
(3 beans = 1
mouse)
No. of
Hawks
(4 mice = 1
hawk)
Total No. of
Organisms
(community)
Area
Total
Mouse
Population
Density
Total Hawk
Population
Density
Group
Trial
Class
Average
Human Impact on Ecosystems and Population Dynamics: Common Assignment 1
Population Dynamics Lab Report
High School Biology Unit 2
8
Scenario 3—Invasive Species Introduction
It seems that your poor mice population cannot catch a break! A truck illegally dumped fill-dirt into your
field, completely unaware that the dirt contained a non-native worm species. This particular species
begins to feed off the roots of the white beans your population of mice depends upon! Although your
sick mice have recovered from the recent fungus outbreak, your food supply is cut short and you can
only gather the green beans for food.
• All the group members who collected food in scenario 1 will collect only the green beans for
one minute.
• After one minute is up, count the beans collected and record this number in the data chart
below. Using this number of beans, calculate the number of mice, hawks, and total number of
organisms.
• Sprinkle these beans back into your ecosystem.
3
No. of Beans
Collected
No. of Mice
(3 beans = 1
mouse)
No. of
Hawks
(4 mice = 1
hawk)
Total No. of
Organisms
(community)
Area
Total
Mouse
Population
Density
Total Hawk
Population
Density
Group
Trial
Class
Average
Scenario 4—Predator Increase
A group of people have shown up and cut the grass in your field—you feel so exposed! You can no
longer hide from predators in patches of tall grass when you are out collecting food. Consequently, the
hawks in the area have taken notice and are increasing in number. As a result of the changing
ecosystem, your equations for determining population numbers have changed. Since gathering food is
now more difficult, the mice need double the energy/food to survive. Because of less cover, the hawks,
on the other hand, require half the energy to hunt and therefore need less food to survive. Don’t forget,
those pesky invasive worms are still eating up your white bean supply. You must continue to only
collect the green beans.
• All the group members who collected food in scenario 1 will collect only green beans for one
minute.
• After one minute is up, count the beans collected and record this number in the data chart
below. Using this number of beans, calculate the number of mice, hawks, and total number of
organisms.
• Sprinkle these beans back into your ecosystem.
Human Impact on Ecosystems and Population Dynamics: Common Assignment 1
Population Dynamics Lab Report
High School Biology Unit 2
9
Your NEW food totals are as follows:
Six beans will feed one mouse
Two mice will feed one hawk
4
No. of Beans
Collected
No. of Mice
(6 beans = 1
mouse)
No. of
Hawks
(2 mice = 1
hawk)
Total No. of
Organisms
(community)
Area
Total
Mouse
Population
Density
Total Hawk
Population
Density
Group
Trial
Class
Average
Scenario 5—Land Development
Your population of mice has figured out why those people cut the grass back so far last year – these
crazy humans are building an apartment complex in your field! As a result of this habitat loss, the area
of your ecosystem has been significantly decreased. Your two-meter by two-meter plot of land is now
decreased to one meter by one meter. Again, remember that the worm species is still present in your
ecosystem and so you can still only collect green beans.
• All the group members who collected food in scenario 1 will collect only green colored
beans for one minute. Make sure to have the young mouse keep time again!
• After one minute is up, count the beans collected and record this number in the data chart
below. Continue to use the food calculations given in scenario 4.
• Pick up all remaining beans in your plot, clean up the area, and return all supplies to your
teacher.
5
No. of Beans
Collected
No. of Mice
(6 beans = 1
mouse)
No. of
Hawks
(2 mice = 1
hawk)
Total No. of
Organisms
(community)
Area
Total
Mouse
Population
Density
Total Hawk
Population
Density
Group
Trial
Class
Average
Human Impact on Ecosystems and Population Dynamics: Common Assignment 1
Population Dynamics Lab Report
High School Biology Unit 2
10
Data Analysis
Once you have finished collecting beans across all 5 scenarios, calculate the area for your plot of land
and use this number to determine the population density of hawks and mice for your ecosystem.
AREA = length x width
POPULATION DENSITY = population/area
4. Plot the population density numbers for both hawks and mice across each scenario in the
graph provided below. Make sure to include title, axis labels (with proper scale), and units.
5. Pick two scenarios and compare the population density data from these two scenarios to that of
scenario 1 (normal conditions). Using the data from your graph, make inferences about your
findings (trends, similarities, differences, etc.).
6. Based on the data, do you accept or reject your initial hypothesis stated in question 1? Justify
your answer.
0
10
20
30
Human Impact on Ecosystems and Population Dynamics: Common Assignment 1
Population Dynamics Lab Report
High School Biology Unit 2
11
Drawing Conclusions
7. Choose one of the human impacts mentioned in the lab and design a solution for reducing or
mitigating those impacts of human activities. Explain how your solution will mitigate the
impacts.
8. Explain two possible sources of error in the lab procedure and the impact of error on your data.
(Meaning, what do you think did NOT work or was possibly confusing about this lab, and how
did it affect your work?)
Application—Apply What You Have Learned!
Using the graph on the next page, answer the following questions.
9. Which species of mussel was present in this waterway in 1991?
10. What was the population density of unionids in 1998?
11. What was the population density of the zebra mussels in 1993?
12. Which of these species is the invasive species? Use data to support your answer.
13. Explain two different ways that the invasive species may bring about the decline of the native
species.
Human Impact on Ecosystems and Population Dynamics: Common Assignment 1
Population Dynamics Lab Report
High School Biology Unit 2
12
Data taken from http://www.caryinstitute.org/educators/teaching-materials/changing-hudson-project/zebra-mussel-invasion-
data , accessed 7/22/2014
0
1
2
3
4
5
6
7
8
9
10
0
500
1000
1500
2000
2500
3000
3500
4000
Unionid mussel density (per m
2
)
Zebra mussel density (per m
2
)
Year
Changes in Mussel Populations
Zebra
Mussels
Unionid
Mussels