By: Kirstin Bittel, Rachel Hughes, and Sally Rusk

Time: 1-2 class periods
Preparation Time: 5 minutes copying overhead
Materials: Biomagnification Overhead
DDT Half Life Overhead

A lesson integrating the creation of algebraic equations with biomagnification.

Purpose – To algebra to explain how the build up of small levels of contaminates can quickly become detrimental to species higher in the food chain

Students will be able to:-
1. Use real data to create an algebraic equation.

Math Standards
Represent and analyze mathematical situations and structures using algebraic symbols.
Use mathematical models to represent and understand quantitative relationships.

Teacher Background
Biomagnification is the increase in a contaminant from one member of the food chain to another.

Resource Websites



Ask student, “Did you know that the chemical DDT, which was banned in the United States in the 1960s is still around and can affect us today? How do you think that is possible?” Allow a few minutes for students to share ideas.

Put up the Biomagnification Overhead.
Ask students the following questions

1. Let's look at our food chain to see how biomagnification works. Let's say for example that each piece of plant material has one microscopic drop of methyl mercury. One insect eats 25 pieces of plant material that would mean that each insect would have__________ microscopic drops of methyl mercury in its body. (25)

2. If one small fish needs 10 insects to live, then one fish would have __________ microscopic drops of methyl mercury. (250)

3. One big fish eats 5 small fish to live. So, one big fish would collect a total of __________ microscopic drops of methyl mercury in its body. (1250)

4. What about you and me? Lets say we eat 1 big fish a day for 3 days. We would collect a total of __________ drops of methyl mercury in our body over the 3 days. This is how biomagnification works! (3750)

So what does this have to do with us?

5. Now let's say that methyl mercury makes living things sick. The more methyl mercury in the living organism, the more sick it would get. From our example above, which organism will be most affected by the toxin methyl mercury? __________

Using the information from you paper and the overhead. Create an algebraic equation that will calculate how much metal mercury is in our bodies based upon how much food our food ate. Keep in mind the number of plants and insect eats is variable.

How do they feel now about GMF’s? Tell students to be prepared to defend their view using evidence from their piece. Students write this information down on easel paper shared between their group to then share with the class.

Did the students correctly calculate the levels of methyl mercury in the example?
Where the students able to come up with a correct algebraic equation with multiple variables?
Where the students able to take the metal mercury model and expand it to DDT?
*Theoretical calculations are ok. M It gives the students an idea of how quickly contaminants add up, but give extra credit to students whose data accurately reflects eating habits of species on the pyramids.

Complete Expand piece to share in class tomorrow.


PULSE is a project of the Community Outreach and Education Program of the Southwest Environmental Health Sciences Center and is funded by:

NIH/NCRR award #16260-01A1
The Community Outreach and Education Program is part of the Southwest Environmental Health Sciences Center: an NIEHS Award


Supported by NIEHS grant # ES06694

1996-2007, The University of Arizona
Last update: March 7, 2007
  Page Content: Rachel Hughes
Web Master: Travis Biazo