Tragedy of the Commons
Modified by Kevin Bryan
Index
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Description
Introduction
Teacher Notes
Acknowledgements
Correlation to Course Description
Correlation to the National Standards
Correlation to the California States Standards
Story
Copy write
Activity
Point Assignment
Handout A
Handout B
Rubric
Score Sheet
The Commons
Pictures
Page #
1
2
2
3
3
3
4
4
5
7
8
9
10
12
13
16
Introduction
Textbooks define “Tragedy of the Commons” as the depletion or degradation of a potentially renewable
resource to which people have free and unmanaged access. The over use of our natural resources by people is a
common topic in environmental science. The availability of clean air, water and soil has decreased dramatically
the last 100 years as the population climbed to over 6 billion people. The lost of undisturbed lands, biodiversity
and other natural resources as the population grew and spread to cover much of the land has dramatically
affected many species. Below is a short explanation of Easter Island
Eastern Island (Rapa Nui) is a small island, isolated in the South Pacific. It was colonized by the Polynesians
about 2,500 years ago. The civilization they develop was based on the island’s towering palm trees, which were
used for shelter, tools, fishing boats, fuel, food, rope, and clothing. Using these sources, they developed an
impressive civilization and a technology capable of making and moving large stone structures, including their
famous statues. However, they used up the islands precious trees faster than they were generated. Once the trees
were gone, the islanders could not build canoes for hunting porpoise and catching fish. Without the forest to
absorb and slowly release water, springs and steam dried up, exposed soil eroded, crop yields plummeted, and
famine struck. When the Dutch explorers first reached the island, they found only 2,000 inhabitants, struggling
under primitive conditions on a mostly barren island, the starving people turned to warfare and possibly
cannibalism. The islanders had lived an unsustainable lifestyle, where they had taken advantage of their
resources, when they didn’t manage their food or natural resources they fell on hard times.
1
Please read “The Commons” section at the end of the handout for additional information and background on the
Tragedy of the Commons. Also there are several pictures at the end of the text from one of my classes.
Teacher Notes:
1) I use a group size of 4 students, three if I have an odd number. I know that other teachers have used up
to six students.
2) There are a lot of different ways to do this activity; many use M&M, Hershey’s Kisses or other candy
that can be picked up easily with a straw or spoon. I prefer the cheese cracker fish, since the students
are fishing for their food.
3) Yes, tell the students they can eat the fish when it is appropriate which will be discussed later.
4) As I begin the activity I tell a story to encourage the students to provide for the people in their country. I
will provide the story in a section below.
5) Some students will complain that you didn’t give them all of the instructions, especially if they over
harvest. Simple state that is correct and that was by design. You probably will learn more this way than
if I told you that you were going to add more fish.
6) After the first round or two, some groups may overfish their oceans; you can allow them to start over.
7) You might want to give each student a country name. This may help with additional ownership. I have
chosen to use countries that might fish the same waters. A list is provided in the instructions. I would
like to thank Dr. Norm Herr, professor at California State University, Northridge for this suggestion.
8) The Commons written paper at the end has the above introduction section at the beginning as this is
meant as a handout to the students after they have completed the activity.
9) The activity has been modified to include the colored goldfish crackers to be predators. Contact me for
the additional activity; it does not have the detail this activity has.
Acknowledgements:
1) A special thanks to Ben Smith at Pales Verdes High School in California. I participated in this activity
in his weeklong workshop. I have made a few changes to fit my style. Plus I have added the different
standards, how I score the activity and the scores sheets I use.
2) Ricky Bermudez, one of my former AP Environmental Students, read material on Easter Island and
wrote the short paragraph about the rise and fall of Easter Island.
3) The Commons section at the end of this activity was written by Gary W. Harding. The website address
is http://members.aol.com/trajcom/private/commons.htm. His last update was 1997, I have modified it
to fit my needs and with some additional information. I plan to add additional examples in the future.
Correlation to the Course Description:
This activity corresponds to several sections of the course description.
III. Renewable and Nonrenewable Resources: Distribution, Ownership, Use, Degradation
All sections A – F.
CORRELATION TO THE NATIONAL STANDARDS
CONTENT STANDARD C:
THE INTERDEPENDENCE OF ORGANISMS
2

Human beings live within the world's ecosystems. Increasingly, humans modify ecosystems as a result
of population growth, technology, and consumption. Human destruction of habitats through direct
harvesting, pollution, atmospheric changes, and other factors is threatening current global stability, and
if not addressed, ecosystems will be irreversibly affected.
CONTENT STANDARD F:
NATURAL RESOURCES
 Human populations use resources in the environment in order to maintain and improve their existence.
Natural resources have been and will continue to be used to maintain human populations.
 The earth does not have infinite resources; increasing human consumption places severe stress on the
natural processes that renew some resources and it depletes those resources that cannot be renewed.
 Humans use many natural systems as resources. Natural systems have the capacity to reuse waste, but
that capacity is limited. Natural systems can change to an extent that exceeds the limits of organisms to
adapt naturally or humans to adapt technologically.
ENVIRONMENTAL QUALITY
 Materials from human societies affect both physical and chemical cycles of the earth.
 Many factors influence environmental quality. Factors that students might investigate include population
growth, resource use, population distribution, over consumption, the capacity of technology to solve
problems, poverty, the role of economic, political, and religious views, and different ways humans view
the earth.
CORRELATION TO THE CALIFORNIA STANDARDS
Biology/Life Science: Ecology
6. Stability in an ecosystem is a balance between competing effects. As a basis for understanding this
concept:
a. Students know biodiversity is the sum total of different kinds of organisms and is affected by
alterations of habitats.
b. Students know how to analyze changes in an ecosystem resulting from changes in climate,
human activity, introduction of nonnative species, or changes in population size.
Story:
Here is a sample story I tell the students as we play the game. The exact story changes every time I do the
activity, but the guidelines are below.
Begin this section by passing out Handout A. As I am passing out the handout, I begin the story.
Students you represent your countries fishing fleet. In order to stay in the game, you must
catch at least one fish. If you don’t you are eliminated from the game. The straw represents
your method of fishing. Fisheries use trawling, long-line with hooks, nets, and traps to catch
fish and other sea animals. You have 30 seconds to catch your fish.
After 30 seconds, tell the students to stop. I usually give them some count down to try to encourage
the students to fish as long as possible and as much as possible.
3
OK, stop. Count the fish you caught and record the data in the table provided. Share your
results with the other members of your group, recording each others results. Now, let’s see
how many fish each group still has left in their “ocean.” Great job groups, your country has
eaten very well this season. Now let’s prepare for the next season.
Now, for round two, for every fish that you have left on your plate, you may add one fish. The
total number of fish on the plate can not exceed 30, the carrying capacity of our “ocean.”
At this point, one or more groups will comment that they don’t have a lot of fish left or none at all.
What do you mean; you have no fish left that means your country will starve during the next year.
OK, I’m a generous guy; you can start over, and add 30 fish to your ocean. It is now time for round
#2. Just a reminder that your goal is to feed your people, if you don’t provide enough food your
nation will starve.
Repeat the above for each round, modifying what you say during and between rounds to encourage the
students to stay active in the game. Most groups will get the idea after 2 or 3 rounds; there will be that one
group that will need some additional guidance to understand the game. Usually, I just encourage them to
take a few minutes and discuss their actions and the results they have after each round. Don’t let them know
when you will end the game or they will overfish the last round.
Now the best pat, allow the students to eat the fish they have caught. Any fish left on their trays at the end of
the game should be eaten by the students.
Copy write: please feel free to use this activity and make changes as needed for your class.
4
Tragedy of the Commons
Purpose:
Materials:
Goldfish, straw, 2 trays (plates), timer, paper (paper towels)
Procedure:
1) You are going fishing. The straw will be your fishing pole. Aspirate through the straw, to catch the
fish. Place the caught fish on your paper. Aspirate: scientific word to suck.
2) Make sure to follow all oral instructions.
3) Divide into groups of 4 students (or other size depending on the class size).
4) Get a tray of goldfish, one straw and one piece of paper per person.
5) Count 30 goldfish onto the second tray.
6) You have 30 seconds to catch your fish, you are feeding your nation with your catch, and you must
catch at least one fish.
7) Go.
8) Count your fish and record in the table. Add the data for all members of your group. Determine the
number remaining.
Students Name
Round #
1
2
3
4
5
6
Starting #
30
# Remaining
9) Count the remaining fish. It should equal the number remaining.
10) Add a column to the end of the table.
11) Add 1 fish for every fish you have left. Maximum number of fish is 30, due to carrying capacity.
Record the number of fish added.
12) Repeat for round two.
13) You must catch a fish to stay in the game.
14) Repeat for additional rounds.
15) Eat your fish.
16) Answer the conclusion questions.
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Results:
Table
Round
#
1
2
3
4
5
6
Tuna
Anchovies Students Name
Starting Starting #
#
Tuna
Tuna
#
#
Remaining Added
Anchovies Anchovies
#
# Added
Remaining
Conclusion:
Please answer the questions completely. Elaboration (explanation) is required to get full value.
1) What happened the first time you went “fishing”?
a. How does this relate to overfishing?
2) Why have time limits? What does the time limit represent?
3) Did your group discuss your actions and strategies before each harvest? If so, briefly relate you’re the
discussion.
4) If there was no discuss, discuss each member’s actions.
5) Do you think each group was affectedly harvesting the ocean? Explain
6) Mathematically, what is the best strategy for harvest the natural resources.
7) How is this a model for sustainability?
8) How is this a model for carrying capacity?
6
Tragedy of The Commons
Point Assignment
Grade: This assignment is worth 100 points. Each Student is responsible for their own written report.
Purpose: 10 points
A descriptive purpose that is written after the activity has concluded (opposite of the usual way).
Table: 20 points
The data is entered in the appropriate locations.
Conclusion
Answer the 8 questions in the conclusion section above. Make sure to elaborate to get full value.
Organization
Typed, tables computerized
Teacher Discretionary Points
Cooperation in your group
Active participation in class debriefing
Description
Purpose
Table
Conclusion
(8 questions x 5
pts)
Organization
Teacher
Discretionary
Points
TOTAL
Possible
Points
10
20
40
Points
Received
Comments
10
20
100
7
Tragedy of the Commons
Handout A
Procedure:
1) You are going fishing. The straw will be your fishing pole. Aspirate through the straw, to catch the
fish. Place the caught fish on your paper. Aspirate: scientific word to suck.
2) Make sure to follow all oral instructions.
3) Divide into groups of 4 students (or other size depending on the class size).
4) Get a tray of goldfish, one straw and one piece of paper per person.
5) Count 30 goldfish onto the second tray.
6) You have 30 seconds to catch your fish, you are feeding your nation with your catch, and you must
catch at least one fish.
7) Go.
8) Count your fish and record in the table. Add the data for all members of your group. Determine the
number remaining.
Students Name
Round #
1
2
3
4
5
6
Starting #
30
# Remaining
8
Tragedy of the Commons
Handout B
9) Count the remaining fish. It should equal the number remaining.
10) Add a column to the end of the table.
11) Add 1 fish for every fish you have left. Maximum number of fish is 30, due to carrying capacity.
Record the number of fish added.
12) Repeat for round two.
13) You must catch a fish to stay in the game.
14) Repeat for additional rounds.
15) Eat your fish.
16) Answer the conclusion questions.
Results:
Table
Students Name
Round # Starting #
1
2
3
4
5
6
# Remaining
# Added
9
Tragedy of The Commons
Rubric
Below is the rubric for grading each section. The bulleted items need to be written in complete sentences.
Purpose: 10 points
 5 points
o catching fish in the allotted time (30 seconds)
o understanding the tragedy of the commons
o other
 10 points
o over use of resources
o conservation of resources
o not to deplete resources
o frailty of our resources
o non-ending amount of food
o greed when it comes to using resources
o other
Table: 20 points
 Multiple rounds – 5 points
 Round 1 where they failed, unless they didn’t fail, see other answers to verify if needed. – 5 points
 Multiple rounds of fishing with data in all columns. – 10 points
Conclusion
Each question is worth 5 points. The answers should include an elaboration for full value.
1) What happened the first time you went “fishing”?
 Over fished, that is all or most were gone – 2 points
 Other – 2 points
a. How does this relate to overfishing?
 This activity shows how catching (overfishing) causes problems with new fish being produced –
3 points
 Other – 3 points
2) Why have a time limit? What does the time limit represent?
 The time limit represents fishing seasons. – 2 points
 Fishing seasons help set limits as to when, where, size and how much fish can be caught. – 3
points
3) Did your group discuss your actions and strategies before each harvest? If so, briefly relate you’re the
discussion.
 Probably not on the first round – 2 points
 Discussion on additional rounds – 2 points
 Elaboration on what was discussed and decided – 1 point
4) If there was no discuss, discuss each member’s actions.
 What were each members actions during the first round. – 5 points
5) Do you think each group was affectedly harvesting the ocean? Explain
 Not during the first round – 1 point, a 2nd point is award if they elaborate on why they didn’t
affectively harvested the first round
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 Multiple rounds – 1 point, a 2nd and/or 3rd point can be award for elaboration
6) Mathematically, what is the best strategy for harvest the natural resources.
 The best strategy is harvesting 15 fish – 2 points
 Explaining why this is the best strategy – 2 points
 Explaining that one member will have less fish (4 member group) or all will have the same (3 or
5 member group) – 1 point
7) How is this a model for sustainability?
 An explanation on sustainability – 2 points
 If the students ultimately develop an understanding how that the ultimate catch is 15 per round –
3 points
8) How is this a model for carrying capacity?
 Maximum amount of fish is 30 because that was in the instructions – 2 points
 If they discuss how the habitat can only support 30 fish because of other limiting factors (food,
predatory/prey, other) – 3 points
Organization
 the document is typed (computerized) – 5 points
 table is organized (neat, easy to read) – 3 points
 overall appearance – 2 points
Teacher Discretionary Points
 Cooperation in your group, worked as a group during the activity, discussion (except first round)
– 10 points
 Active participation in class debriefing – 5 points
 Other points – up to 5 points
o Extra ordinary written report
o Pictures
o Graph
o Other
Recording the Points
The points are placed into a copy of the table below. The grader should make comments about what the student
has written.
Description
Possible Points
Comments
Points
Received
10
Purpose
20
Table
40
Conclusion
(8 questions x 5
pts)
10
Organization
20
Teacher
Discretionary
Points
TOTAL
100
Tragedy of The Commons: Score Sheet
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Name
Description
Purpose
Table
Conclusion
(8 questions x 5
pts)
Organization
Teacher
Discretionary
Points
TOTAL
Possible
Points
10
20
40
Period
Points
Received
Comments
10
20
100
Tragedy of The Commons: Score Sheet
Name
Description
Purpose
Table
Conclusion
(8 questions x 5
pts)
Organization
Teacher
Discretionary
Points
TOTAL
Possible
Points
10
20
40
Period
Points
Received
Comments
10
20
100
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The Commons
Introduction
Textbooks define “Tragedy of the Commons” as the depletion or degradation of a potentially renewable
resource to which people have free and unmanaged access. The over use of our natural resources by people is a
common topic in environmental science. The availability of clean air, water and soil has decreased dramatically
the last 100 years as the population climbed to over 6 billion people. The lost of undisturbed lands, biodiversity
and other natural resources as the population grew and spread to cover much of the land has dramatically
affected many species. Below is a short explanation of Easter Island
Eastern Island (Rapa Nui) is a small island, isolated in the South Pacific. It was colonized by the Polynesians
about 2,500 years ago. The civilization they develop was based on the island’s towering palm trees, which were
used for shelter, tools, fishing boats, fuel, food, rope, and clothing. Using these sources, they developed an
impressive civilization and a technology capable of making and moving large stone structures, including their
famous statues. However, they used up the islands precious trees faster than they were generated. Once the trees
were gone, the islanders could not build canoes for hunting porpoise and catching fish. Without the forest to
absorb and slowly release water, springs and steam dried up, exposed soil eroded, crop yields plummeted, and
famine struck. When the Dutch explorers first reached the island, they found only 2,000 inhabitants, struggling
under primitive conditions on a mostly barren island, the starving people turned to warfare and possibly
cannibalism. The islanders had lived an unsustainable lifestyle, where they had taken advantage of their
resources, when they didn’t manage their food or natural resources they fell on hard times.
Can we relate what is happening on earth today to what happened on Easter Island over 500 years ago? Read
on for further discussion on the Tragedy of the Commons and other examples. If you know of other examples
you would like to see included in this handout, feel free to contact me, Kevin Bryan, at www.thegreenpath.net.
What is the Commons?
The "commons" is any resource which is shared by a group of people, cities, states or countries. Such things as
the air we breathe and the water we drink come from commons. In many parts of the world; new land for
farming and grazing land for stock, fish from the sea, and wood for fuel and housing are treated as commons.
What is the Logic of the Commons?
The "logic of the commons" is as follows: Each country has the right to take resources from and put wastes into
the commons. To accumulate wealth, each country believes that it can acquire one unit of resources or dump
one unit of waste while distributing one unit of cost across all of the countries with whom the commons is
shared. Thereby, the gain to the country appears large and the cost very small. Some countries accumulate
wealth more rapidly than others and this, in turn, gives them the means to access an even larger share of the
commons.
The problem in the logic of the commons lies in the failure to recognize that all countries are attempting to do
the same thing. Thus, on average, one unit of gain for a country actually produces a net one unit of cost for each
country. However, selfish countries accumulate wealth from the commons by acquiring more than their fair
share of the resources and paying less than their fair share of the total costs. Ultimately, as population grows
and greed runs rampant, the commons collapses and ends in "the tragedy of the commons".
How does the Commons work?
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The logic of the commons breaks down when resources decline and/or population grows too large. Consider the
following example: Fourteenth century Britain was organized as a loosely aligned collection of villages, each
with a common pasture for villagers to graze horses, cattle and sheep. Each household attempted to gain wealth
by putting as many animals on the commons as it could afford. As the village grew in size and more and more
animals were placed on the commons, overgrazing ruined the pasture. No stock could be supported on the
commons thereafter. As a consequence of population growth, greed, and the logic of the commons, village after
village collapsed.
An apparent solution to avert the collapse of the commons was the introduction of private ownership. Common
lands were parceled up into small tracts, each owned by a household. If a household greedily destroyed its plot,
its demise was its own fault. However, as population grew, each new generation of households was left with a
smaller and smaller portion of the original holdings. And, there was still the opportunity for some households to
accumulate wealth by acquiring land from others, one way or another. Thus, private ownership did nothing to
control greed. It merely shifted to a new arena. The number of landless households grew rapidly, each one
descending deeper and deeper into abject poverty.
Commons other than land were not so easily parceled up. How could anyone own rain, wind, and the open
ocean? The logic of the commons still prevails today for: fishing rights in coastal and open waters; roads and
highways for travel and commerce; and a standing military for defense of territory.
The logic of the commons also includes a much more sinister element. As an example, consider the following
episode:
"After the Civil War, the cattlemen in Edwards County, Texas overstocked the land, and when settlers
started showing up in the 1880s, the cattlemen's answer was to crowd even more animals onto the land.
At a stockmen's meeting, they produced: 'Resolved that none of us know, or care to know, anything
about grasses, native or otherwise, outside of the fact that for the present, there are lots of them, the best
on record, and we are after getting the most of them while they last.' (D. Duncan, MILES FROM
NOWHERE, Penguin Books, 1994, pg. 145)."
Thus, we have cases of deliberate destruction of the commons to not only get the wealth out of it before
someone else does, but also to leave nothing for others. Often, this has involved the ruin of other commons
resources along with the ones sought after. The history of the quests for gold and whales are other examples.
These kinds of episodes reflect instances of pure greed.
The commons is an ancient cultural and economic organizing principle. Before the agricultural revolution, each
clan or tribe staked out a territory and all members had the right to hunt and gather within it. They often did so
cooperatively. This worked well as long as their territory could be held, the commons was vast, and the relative
population was small. Before the agricultural revolution, a commons tragedy was rare. It usually involved
declining resources due to natural events, such as ice-ages. The tragedy of the commons has become more and
more frequent since the agricultural revolution and its concomitant population growth. Its frequency has
accelerated with the industrial revolution and the resultant population explosion. Now, the commons includes
the whole Earth.
Why does the Commons continue?
In addition to the obvious (land, water, and air), much of our world is still treated as a commons today. In many
cases, resources from these commons are no longer free for the taking. Dumping our wastes into the commons
is not as free as it once was. One must pay a fee or be licensed to get access to the commons. In some cases,
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how much one can take away or dump into the commons is managed and/or regulated. But, all around the
world; fisheries, wood, national parks, highways, parking and many other resources are commons just the same.
Access to them merely requires a desire to do so and sufficient means.
Population growth, greed, and the logic of the commons has virtually destroyed the world’s ocean fisheries and
the Amazon rain forest. Huge tracts of land have succumbed to desertification. Crowding overwhelms Yosemite
National Park and the freeways and parking facilities in our big cities. The accumulation of greenhouse gasses
in the atmosphere is precipitating significant global warming which will produce climate change. A significant
loss of biodiversity is underway; some call it a mass-extinction event.
Although international negotiations on managing the global commons for a sustainable yield continue, progress
toward resolution is nil. Selfish points of view dominate the discussion. Particularly intractable is control of
population growth. The freedom to breed has been called "the second tragedy of the commons". Without
population-growth control, greed and the logic of the commons makes a global-wide tragedy of the commons
inevitable.
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Tragedy of the Commons
Pictures of my students doing the Tragedy of the Commons
Students fishing for their Countries.
The end result, they have completely harvested their fish. The students were
initially set-up to fail, that is to catch all the fish.
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The group has successfully harvested the fish sustainable method.
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