Experimental Science I Unit 1: Ecosystem Interactions and Energy
Culminating Project
Unit Essential Question: How can we create the ideal living situation for humans living in a biosphere
on Mars?
Challenge
The year is 2150. Earth is overpopulated and its resources are depleted. Scientists are looking to create
enclosed spaces on Mars that people can move to create a better quality of life. You and your team are going to
work together to design and engineer a biosphere on Mars that will give a group of humans the space and
resources they need to have a happy and healthy life. There are many things to consider when designing your
biosphere- carrying capacity, the creation and maintenance of biodiversity, and the cycling of matter and
energy, to name a few. How your design team approaches these factors is up to you and the decisions that you
make will affect the ability of life to survive in your biosphere. Once your group determines how best to
approach these factors and how best to design an artificial biosphere that offers solutions to Earth’s problems,
you will create a marketing video used to sell your design to a group of scientists that the leaders of Earth have
tasked with solving this problem. As individuals, you will write a news article that illustrates the problems the
Earth is facing and also serves as an advertisement for the biosphere you have created.
Background Information:
Earth in 2150 will be facing the following issues:
 The population of Earth has reached 20 billion people, double the amount that scientists predicted that
Earth could support. The concentration of individuals in urban areas has skyrocketed, as these areas
offer more resources and jobs then rural areas. The unemployment rate has reached a staggering 74%
as there are simply not enough jobs to support the population.
 Resources like food, clean water, and fossil fuels are scarce. Hoarding of resources and capital has
caused wealth inequality to reach unprecedented levels. Most of the world’s wealth is owned by less
then 0.00001% of the population.
 The burning of fossil fuels has caused the ozone layer to be depleted, causing major climate change and
the melting of the polar ice caps.
 Climate change has caused major areas to submerge under water, including cities such as Miami,
Venice, and Amsterdam. Many of the world’s matter and energy cycles have been disrupted.
 The evolution of certain viruses has caused certain types to be resistant to antibiotics. One result is
that an unknown plant virus has caused crops to fail, further exacerbating the food supply of the world.
 Many of the Earth’s rainforests have been destroyed in an effort to supply the world with resources and
land. This has disrupted the carbon cycle and severely threatened biodiversity.
 The lack of resources has caused wars among nations who have chosen to hoard resources such as oil.
 The desperation to survive has caused a panic among its people. Governments and organizations like
the United Nations who are tasked to protect the world have broken down and become ineffective.
Group Project Criteria for Success
o
o
Summarize the situation of Earth in 2150 to your audience.
Propose a Solution:
- Explain the concepts of population growth: How are you going to choose who goes to your
biosphere? How are you going to ensure enough resources are available? How are you going to
regulate population growth? How are you going to ensure space for future generations?
- Explain the concepts of energy and matter cycles: How are you going to regulate the carbon and
nitrogen cycles? How are you going to ensure enough resources (food, water, energy, space) for
your population? How are you going to ensure these resources are renewable?
- How are you going to introduce biodiversity into your biosphere? How are you going to maintain
and regulate proper food chains in your biosphere?
- How are you going to provide services and jobs for your biosphere?
o
Have High Video News Quality Segment
- Includes a visual model that shows the layout of your biosphere and a diagram of its functioning.
- Is organized logically
- Is interesting to the audience
- Practices good oral presentation skills
Individual Project Criteria for Success
Your news article should:
o
o
o
o
o
Explain briefly the situation on Earth.
What method do you think is best to regulate population control? Explain the problem with
exponential growth related to resource availability. Provide an example of how appropriate population
control has been regulated in the past.
Explain the proper functioning and the importance of maintaining the carbon and nitrogen cycles.
What factors have caused their disruption? What can be used to protect them in the future?
Explain the importance of biodiversity. What factors have caused the decline in biodiversity? Imagine
it is the future: Choose a species that has become extinct and describe the effects its extinction has
caused. Include information about its place in the food chain and at least one example of how it
cooperated and benefited another species.
In what specific ways would you educate present-day citizens of the world to prevent this possible
future?
Experimental Science I Unit 1: Ecosystem Interactions and Energy
Culminating Project
Project Organizer
Lift-Off Task:
You will be designing a solution to the problem of overpopulation and resource
The Earth in 2150
depletion on Earth. In order to develop a solution, we need to learn everything we can
about what is necessary for Earth to function the best it can.
 Summarize what you already know about overpopulation and resource
depletion, including:
o Possible negative consequences.
o The types of methods humans use to prevent overpopulation and
resource depletion.
Task 1:
Population Growth
and Resources
In this task you learned how population size is affected by resource availability.
Reflect on what you learned and individually answer the following questions in your
Project Organizer:
 Which resources do you think would be major limiting factors in your
biosphere?
 How will you determine the carrying capacity of your biosphere, making sure
that it allows for the “ideal living situation?”
 How will you plan for future generations in your biosphere?
 How will you ensure that the population of your biosphere doesn’t misuse its
resources?
Task 2:
The Cycling of Matter and
Energy
In this task you learned how matter and energy cycle on the Earth and ways in
which these cycles have been negatively impacted by human activity. Reflect on
what you learned and individually answer the following questions in your Project
Organizer:
 How would you create the carbon and nitrogen cycles in your biosphere
and how would you ensure that they do not become disrupted?
 How would you establish food chains in your biosphere and ensure that
they do not become disrupted?
Task 3: Biodiversity and
Its Protection
In this task you learned the importance of biodiversity and how it has been
negatively impacted by human activity. Reflect on what you learned and
individually answer the following questions in your Project Organizer:
 What is your plan for creating and maintaining biodiversity on your
ecosystem? What habitats will you create to support them? What specific
types of species are integral to your biosphere?
Experimental Science I Unit 1: Ecosystem Interactions and Energy
Lift-Off Task: The Earth in 2150
Unit Essential Question: How can we create the ideal living situation for humans living in a biosphere on Mars?
Part A: If you were to describe the ideal living situation for a human on Earth, what types of things would you
consider? Individually, record the factors of life that you think are important to a human having a happy,
healthy life on Earth.
Part B: As a group,
Discuss what factors each member wrote on his or her list.
On a large sheet of poster paper:
 Write the phrase “Happy, Healthy Earth” in the middle of your poster and draw a circle around it.
 Around the circle, record the factors that were similar across your group.
 Draw lines to link together factors that relate to each other.
 Think about these factors. As a group, discuss things that might prevent humans from having these
factors. For example, lack of jobs might prevent all humans from having money. Connect these
problems with the factors on your poster.
Post your group poster on the wall.
Walk around and look at each groups’ ideas.
Part C: As a whole class,
Construct a class concept map with the phenomenon in the middle: “Happy, Healthy Earth”
 Decide which key factors you want to have on the concept map.
 Draw lines with arrows between two key factors to show that there is a relationship.
 Make as many connections as you can between the factors on the concept map.
It’s important for everyone to share their ideas and it’s okay if you don’t agree.
You will revise and add new factors and problems to achieving these factors as you learn more about
ecosystem interactions and energy.
Unit Essential Question: How can we create the ideal living situation for humans living in a biosphere on Mars?
Connecting to the Culminating Project
You will be designing a solution to the problem of overpopulation and resource depletion on Earth. In order to
develop a solution, we need to learn everything we can about what is necessary for Earth to function the best it
can.
 Summarize what you already know about overpopulation and resource depletion, including:
o Possible negative consequences.
o The types of methods humans use to prevent overpopulation and resource depletion.
This should be completed individually in your Project Organizer.
Reflection:
Individually, reflect on the Lift-Off Task, using the questions provided:
1. At the beginning of this task, you made a list of all the factors you thought were necessary to a healthy,
happy life on Earth. Look back at your list: think about the factors your peers considered that you did
not initially write down. How are those factors different from the ones you originally considered? Why
do you think they were different from yours?
2. In this unit, we will be focusing on four crosscutting concepts:
 Patterns: Graphs, charts, and images can be used to identify patterns in data.
 Scale, Proportion, and Quantity: There are proportional relationships between different types of
quantities.
 Systems and System Models: Models can be used to represent systems and their interactions.
 Stability and Change: We can examine forces at different scales to explain stability and change.
Looking at your class concept map, give one example of how a crosscutting concept came up
in today’s task.
3. Now that you understand what project you will be working on over the course of this unit, what else do
you need to know? What additional questions do you have?
Experimental Science I Unit 1: Ecosystem Interactions and Energy
Task 1 Vocabulary
Term
Carrying capacity
Population
Community
Ecosystem
Limiting factor
Density-dependent
factor
Density-independent
factor
Abiotic factor
Biotic factor
Exponential Growth
Logistic Growth
Definition
Diagram, Picture, or Examples
Experimental Science I Unit 1: Ecosystem Interactions and Energy
Task 1: Population Growth and Resources
Unit Essential Question: How can we create the ideal living situation for humans living in a biosphere on Mars?
Engage: Carrying Capacity
In the Culminating Project Challenge, we found out that in the year 2150, the Earth is overpopulated and its
resources are depleted. We need to learn everything about how the Earth’s environments can successfully
interact and what might have happened to disrupt these successful interactions in the year 2150. What main
factors might have caused the disruption of successful environmental interaction on Earth?
It is important to understand the concept of the carrying capacity in environments. Just by looking at this
term, what do you think carrying capacity refers to? Discuss in groups.
The carrying capacity of an ecosystem is considered the maximum population size that environment can
support. In order to understand carrying capacity of a specific species in the environment, scientists look at the
population of deer in Yellowstone Park. Before we understand the carrying capacity of humans on Earth, let’s
practice our understanding of the concept by looking at deer in a forest in pairs:
1. In this graph, what do you think that X refers to?
2. The population of deer in this forest almost reached
100, but it then decreased. Why do you think this
happened? What might have caused this?
3. How do you think this graph can help us understand
the population of humans on Earth?
The interaction of organisms in an environment is very important to it functioning successfully. If an organism
is introduced into an environment where it doesn’t belong, this can greatly disrupt the ecosystem. This is what
happened in Australia with the introduction of the cane toad.
(https://www.youtube.com/watch?v=w2bwUlu3eMc)
Summarize this video by describing why the population of cane toads increased.
However, introduction of a species can also help an environment, as happened in Yellowstone Park with the
introduction of the wolf.
https://www.youtube.com/watch?v=ysa5OBhXz-Q&feature=youtu.be
Summarize this video by briefly describing how the introduction of wolves changed the rivers in Yellowstone
Park.
Explore: Limiting Factors
A group of organisms of the same species form a population. All of the blackbirds in a forest form a population,
for example. Groups of populations living together form a community. All of the blackbirds, rabbits, and deer
in a forest form a community, for example. An ecosystem is a group of communities that also includes biotic
(living) factors and abiotic (nonliving) factors. Individually, fill in the table with any biotic and abiotic factors
can you think of that exist in an ecosystem.
Biotic Factors
Abiotic Factors
As a group, discuss what you added, including any factors others thought of that you didn’t.
The growth of a population is controlled by factors within the environment that limit the population’s size.
These are called limiting factors. A limiting factor is a finite resource that determines the population of an
organism in an environment. If something is finite, that means you can run out of it. Limiting factors most
commonly include availability of living and nonliving resources, predation, competition and disease. They can
be considered density dependent, meaning the factors’ impact is based on the size (density) of the population,
or density independent, meaning the factors will have the same impact regardless of the population. For
example, competition is density dependent, whereas a natural disaster is density independent. Individually,
think about what resources might serve as limiting factors to humans and write down your ideas.
Limiting factors to a human population:
Density-dependent:
Density-independent:
As a group, discuss what limiting factors you thought of. Write down any others your group members included
that you did not.
Panther Hunt
Today our classroom represents the habitat of a population of panthers and each of you represents one panther
that lives in this habitat. A panther requires 50 kg of food per month to survive. The cups that have been
spread out in the classroom represent food the panther can prey upon. The chart on the screen shows what
animals the letters written on the cups indicate as well as the mass of the animal. Most of you will be single,
healthy panthers, but some of you will be injured, some blind, and some will have babies to support. Each
panther must walk into the habitat, find a prey animal, and carry it to his or her den (their desk). Each panther
can only carry one prey animal at a time. Panthers do not run, fight over prey, or steal prey from each other!
When all prey is collected, each panther should go to their den and calculate how much prey they collected.
1. How many kilograms did the average panther gather? ___________
2. How many panthers survived in this habitat? _________ Is this the carrying capacity for this habitat?
_________ If no, how could we determine the carrying capacity of this habitat?
3. If 10 new panthers entered this environment, would this habitat support them? _________ How many
kilograms of food would be needed for a population of 25 panthers?
4. How many kilograms did the blind panther gather? __________ The injured panther? __________ What does
this say about their ability to survive in the wild?
5. How many kilograms did the mother panther gather? __________ If the mother panther had 2 cubs and
they each require 25 kg of food to survive, how many members of this family do you think would
survive?
Explain: Exponential vs. Logistic Growth
Use the data in the tables below to construct a corresponding graph that best represents the data. Make sure
your y-axis increments are even and appropriate and that both axes are labeled appropriately.
Table A.
Graph A.
World Population of
Humans (1700-2150)
Year
1700
1750
1800
1850
1900
1950
2000
2050
2100
2150
Population
(in billions)
0.6
0.7
0.9
1.2
1.7
2.5
6.0
9.5
14.0
20.0
Table B.
Graph B.
Atlas Mountains
Panther Population
(1930 - 2020)
Year
1930
1940
1950
1960
1970
1980
1990
2000
2010
2020
Population
(in
thousands)
0.5
1.1
1.8
2.8
4.1
5.7
7.7
7.1
7.0
7.0
Discuss at your table and write a response below.
1. In your own words, describe the difference between the two graphs.
2. Do you think that Graph A will ever look like Graph B? Explain why or why not?
3. If you had to describe Graph A as a letter of the alphabet, what letter would you choose? _______
4. If you had to describe Graph B as a letter of the alphabet, what letter would you choose? _______
There are two main types of population growth: Exponential Growth and Logistic Growth



When unlimited resources are available, populations exhibit exponential growth, resulting in a Jshaped curve on a graph. Exponential growth cannot occur indefinitely, as eventually a population will
run out of resources.
Logistic growth takes into account these limiting factors and carrying capacity of a population in a
specific ecosystem. In logistic growth, the depletion of resources will slow the rate of growth, eventually
reaching a plateau, resulting in an S-shaped curve on a graph. This is the carrying capacity of a
population (mathematically, carrying capacity is represented by the letter K).
The following graphs visually demonstrate the difference between exponential and logistic growth:
1. Which graph from the previous page showed exponential growth? _____________
2. Which graph from the previous page showed logistic growth? _____________
While observation of growth in a population would produce the most accurate results, this is not always
possible, particularly in species that grow very large populations quickly such as bacteria. For this reason,
scientists use mathematical and computational models to represent population growth:
Practice: If a population starts with 100
individuals, and has a growth rate of 0.05,
calculate the population size after 1 year.
Practice: If a population has 500 individuals, a
carrying capacity of 2000 individuals, and a
growth rate of 0.35, calculate the change in
population size over a month.
Elaborate: Yeast Habitat Carrying Capacity Lab
Yeast perform a process called fermentation in which they use sugar for energy. This process creates carbon
dioxide (CO2) as a byproduct. Two different solutions have been created using sugar- one 25% sugar solution
and one 50% sugar solution. Using these solutions as “habitats,” you will indirectly measure the carrying
capacity of yeast in these habitats. The sugar will serve as the limiting factor in the experiment and should
determine the carrying capacity of the yeast. The carrying capacity can be indirectly measured by equating the
amount of yeast with the amount of carbon dioxide produced. By measuring the diameter of a balloon over time,
we can measure how much carbon dioxide is being produced in the habitats and, thus, how the population of
yeast in these habitats grow.
What differences do you think you will see between the 25% sugar solution and the 50% sugar solution?
Why do you think this will happen? Write a justification for your answer in #1.
What is the independent variable of this experiment?
What is the dependent variable of this experiment?
Procedure:
1. To prepare the 25% solution, mix 5 mL of sugar with tap water until you get 20 ml of solution. Mix the
solution with a stirrer until the sugar is dissolved. Pour the solution into a test tube and label the tube
“25” with a grease pen.
2. Rinse your measuring cup or graduated cylinder well and add 10 mL of sugar. Add another 10 mL of
water to make 20 mL. Mix the solution with a stirrer until the sugar is dissolved. Pour the solution into
a test tube and label the tube “50” with a grease pen.
3. Add your initials to each tube.
4. With the group next to you, mix a packet (7 grams) of yeast into 200 mL of warm tap water. You will be
using this same 200 mL yeast solution between both groups.
5. Stir the yeast into the warm water until it is evenly suspended in the solution.
6. Add 25 mL of the yeast solution to your 25% sugar solution; then add another 25 mL to your 50%
solution.
7. Immediately place a balloon over each test tube and secure each balloon with 1 or 2 rubber bands. With
your thumb over the top of the tube and balloon, shake each tube gently for 2 minutes.
8. Please each tube in the rack in warm water bath.
9. Using a ruler, record the diameter of the balloon in centimeters using the time intervals listed in the
table on the next page. Record this data in the table.
Table 1:
Diameter 25%
of
solution
balloons
(cm)
1 minute
3
minutes
5
minutes
7
minutes
9
minutes
11
minutes
13
minutes
50%
solution
Diameter
of
balloons
(cm)
15
minutes
17
minutes
19
minutes
21
minutes
23
minutes
25
minutes
25%
solution
50%
solution
Graph the rate of both balloons’ inflation below (use a separate line of a different color, noting which is which).
Make sure to use correct the correct axes for independent and dependent variables and the correct increments.
Label your axes correctly.
Graph 1:
Which balloon (25% or 50%) inflated the most?
Why do you think this occurred?
The solutions of sugar were models of limiting factors in an environment? Explain how the availability
of sugar to yeast in a test tube is similar to availability of resources in a habitat:
What happened to the yeast population when we doubled the limiting factor in its habitat?
Could doubling the limiting factor of a habitat have any negative effects to that habitat and the wildlife
within it? Explain.
Evaluate: Connecting to the Culminating Project
You will be designing an artificial biosphere on Mars that will represent the ideal living conditions for humans.
In this task you learned how population size is affected by resource availability. Reflect on what you learned
and individually answer the following questions in your Project Organizer:




Which resources do you think would be major limiting factors in your biosphere?
How will you determine the carrying capacity of your biosphere, making sure that it allows for the “ideal
living situation?”
How will you plan for future generations in your biosphere?
How will you ensure that the population of your biosphere doesn’t misuse its resources?