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
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