Tragedy of The Commons

Photo credit: Dan Barbus at www.everystockphoto.com

How can we better work together to manage and care for our community resources?  What natural consequences occur over time when people act only in their own interest in the short term?  These are among the questions that ecologist Garrett Hardin described in his prescient 1968 article "Tragedy of the Commons", which provided a jumping off point for a fourth and fifth grade exploration in the Studio Lab.


Students worked in small groups, and each represented a "family" in a lakeside community.  A piece of paper stood in for the lake, and 16 goldfish crackers represented the fish living in it.  Studio Teacher, Julia Gonzales, described the scenario: Each year, each family will catch "fish" from the lake.  They need one fish for their family to survive, two fish enable them to live very comfortably, and if they caught more, they can sell them for a profit. 

Students took turns "catching" fish for the first round, which represented the first year.  At this point, they learned new information: that each fish remaining in the pond can reproduce, doubling the number that survive.

Each team then proceeded to "fish" for three more turns, or "years", and recorded their catch and fish population data on a group data sheet.

Ms. Julia led the class in a discussion of their data, and the effect that each community's choices had on the sustainability of the lake's resources.

Some individuals chose to catch the maximum number of fish at each turn, quickly depleting the lake's population of fish.  Other groups planned more carefully, ensuring that their community would thrive on an abundance of fish. 

The Tragedy of the Commons exercise uses math skills to explore themes students are learning in Social Studies, as well as their Life Science unit about ecosystems, biodiversity, organism survival, and competition in food chains.  It provides entry for ongoing discussion about environmental stewardship, global hunger and pollution, and extends students' awareness of how they might better manage their own shared resources, by re-shelving their own books in the library, for example.

For another perspective on the Tragedy of the Commons, here is a brief animated summary that you might like to check out:

If you have trouble viewing it, try this link instead: Tragedy of the Commons.

For more on Walgrove's Studio Lab Program, click here: http://publicschoolstudio.blogspot.com/p/faq.html .

Food Chain Investigation With Owl Pellets

Today, Ms. Laichtman led a 4th grade investigation of the food chain and energy transfer, through the dissection of owl pellets.  Students worked in groups of twos and threes to extract and identify bones from owl pellets to find evidence of their diet.

Every student successfully found and identified bones within the pellets: skulls, jaws, ribs, vertebrae.  Students then mounted their bones onto a chart, before writing about their findings and interpreting their results.

Decomposers!

We began our fourth grade Life Science unit by studying decomposers: organisms such as fungi, worms and bacteria that break down dead or decaying material to use for food.

We created a classroom earthworm bin, and took turns filling it with soil, newspaper and vegetable scraps, and a hundred or so earthworms from my compost bin at home.

Students will continue to add fruit and vegetable leftovers, keep it moist and stir the contents regularly.  We'll observe the bin, and take note of the soil level and how quickly the food items disappear.  We'll cover the bin to keep it dark, and look for earthworm tunnels through the glass at feeding time.


Here are some time-lapse videos of decomposers at work. 

First up, mushrooms and other fungi:



And here are two more:

Mold decomposing a watermelon:  http://www.youtube.com/watch?v=S12zZhdOckc

Ants decomposing a gekko:    http://www.youtube.com/watch?v=R3Mt2E1M6dU

Enjoy!