Debate: Are Monarchs at Risk From Bt Corn?
Teacher Lesson Plan
By Doug Golick
Copyright University of Nebraska-Lincoln 2001
In 1999 researchers from Cornell University published a letter in the journal Nature that showed Bt corn pollen had toxic effects on larvae of the monarch butterfly. The monarch caterpillar feeds on milkweed plants. Because some milkweed grows next to cornfields, Losey and his Cornell colleagues suggested that Bt corn pollen might drift onto milkweed and harm the monarch larvae. Although only a note and not a full scientific investigation, the Cornell letter garnered a tremendous amount of media coverage and gave anti-biotech advocates a poster species for their cause. In the following year the EPA, biotech companies, and university researchers studied the potential impact of Bt corn pollen on the monarch butterfly and related species. Their research findings were published in September 2001 in a series of papers
Opposing students groups will conduct a debate on the statement, "Monarch butterflies are at significant risk from Bt pollen". One group will be given a paper that supports the statement, the opposing group will be given a paper that supports the anti-statement.
Each group will then argue points to prove their case.
1. Students will gain a better understanding of the monarch butterfly and Bt corn controversy.
2. Students will demonstrate their understanding of supporting a statement with evidence.
3. Students will demonstrate their understanding of argumentation and make a conclusion about the monarch controversy.
1. Divide the class into two groups:
a. The first group will argue for the statement that monarch butterfly larvae are at significant risk from the Bt corn pollen
b. The second group will argue the belief that there is negligible risk to monarch butterfly larvae.
2. Each group will be given a paper to prove their stance
Group a (for the statement) will receive the paper:
John E. Losey, Linda S. Rayor, Maureen E. Carter (Department of Entomology, Cornell University). Transgenic Pollen Harms Monarch Larvae . Nature, 399. May 20, 1999
Group b (against the statement) will receive:
Impact of Bt corn pollen on monarch butterfly
populations: A risk assessment
PNAS published September 14, 2001, 10.1073/pnas.211329998 ( Agricultural Sciences )
3. Using their papers as evidence each group will make their case for or against the statement.
4. Students will be given a series of debate points to prepare arguments for their position.
5. The class will then regroup and debate will begin with the class instructor refereeing.
Argument Points for the Debate:
Students will be arguing points in support for their stance on the statement, "Monarch butterflies are at significant risk from Bt pollen".
A member from each group will each be given a minute to argue each point except for the closing statement in which they will receive two minutes.
Group a (for below statements)
Group b (against below statements)
Bt corn pollen is hazardous to monarch butterfly larvae.
Bt corn pollen collects on milkweed at levels that harm monarch butterfly larvae.
A significant portion of monarch butterfly larvae is exposed to Bt corn pollen.
Closing Argument: Bt corn pollen is a significant risk to Monarch butterfly populations
Students should be assessed by their demonstration of understanding for the outlined objectives in this lesson plan.
Students may be graded on their demonstration of understanding through how effectively they argue their stance with supportive materials. Students may also be graded on their level of participation.