This investigative case module was prepared as part of a BioQUEST faculty development workshop entitled NSF Chautauqua Short Course: Investigative Cases at Christian Brothers University in July 2004. The cases, resources, and implementation strategies were developed by participants for use with their own students. We invite you to adopt and adapt the following materials.

The BioQUEST Curriculum Consortium is committed to the reform of undergraduate biology instruction through an emphasis on engaging students in realistic scientific practices. This approach is sometimes characterized as an inquiry driven approach and is captured in BioQUEST's three P's (problem-posing, problem-solving, and peer-persuasion). As part of this workshop groups of faculty were encouraged to initiate innovative curricular projects. We are sharing these works in progress in the hope that they will stimulate further exploration, collaboration and development. Please see the following links for additional information:

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Investigative Cases
   
The Case: Terminator Genes in Seeds

As the sun and dust settled, Ben, Ashley’s brother, clattered up in his old pickup.

“Ashley,” Ben called, “time for supper. Let’s close the produce stand.”

Ashley finished counting out her customer’s change and gently packaged the produce she and her family had grown into a cardboard box. She and Ben closed the stand and drove past their fields of corn and soy to the house.

As the dinner plates passed and filled with new potatoes, sweet corn, and fresh tomatoes, Grandpa began to express his concerns over the CNN broadcast on the release of terminator seeds to the world market.

“Those Monsanto rascals and their terminator seeds! It’s the Bt corn all over again!” Grandpa exclaimed. They’re takin’ over the world with their fancy technology! Soon no one will be able to eat without their permission!” He pounded his fist on the table.

“What’s a terminator seed?” asked Kyle, the youngest child. Only in the fourth grade, he envisioned seeds with dark glasses and automatic weapons.

“It’s not the seed, Kyle" answered Dad. "It’s the genes that they have in them. The genes kill the seeds so they can’t grow.”

Grandpa ranted again about company and government conspiracies and rattled the silverware once more.

“Now Pop….” calmed Ashley’s mother. "What's the chance that could happen?"

“What could happen!?” Ben asked with his mouth full of potatoes.

“Lateral gene transfer,” Ashley piped in. “It’s when the genes of one organism, like a plant, gets into the genes of another organism.”

“What’s the chance that Terminator seeds could really end up in other crops, like ours, killing our seed?” Mom asked as she glanced in nervous query at her husband.

“What’s a terminator seed?” Kyle interrupted again.

Ben put down his fork. “Somebody says that those genes could get into poor people’s crops, or the crops of people who don’t buy those seeds. Others say that everyone will have to buy them because the big seed companies are a monopoly. Everyone will eventually buy them because they’re so cheap. Then, we’ll all have to buy their seeds or starve.”

The family was suddenly silent, partly out of concern over the subject, and partly in surprise at Ben’s lucidity.

“What’s a terminator seed?” Kyle pleaded.

Case Author:
Lucinda Swatzell Southeast Missouri State University

Case Analysis

1. lateral gene transfer
2. biotechnology
3. ethical issues of GMO
4. multigenerational families
5. government responsibilities and interaction with big business
6. ethics of monopolies on food
7. ownership of technology

Option: Include a know / need to know chart like the one below:

What do you know?
What do you need to know?
   

Learning Goals

Goal(s)

To lead students to examine material on early plant development and to use that information to consider current issues regarding GMO, company, government, and consumer responsibility, and ownership of technology. In addition, students will establish and adequately defend an informed opinion on business ethics, responsibility, ownership, and the world food supply.

Standards

n/a

 

Investigations and Activities

1. Divide students into groups. Provide each group with an assignment.

In order, reading materials should address these -- questions:

-- How and why did humans begin to rely on agriculture for their dietary and medicinal needs?

-- How did corn and rice become cultivated in the United States?

-- What effect does the ability to control a food source have on the quality of human existence?

Group #1 - Read "In Search of Origins" (Smith, 1995).
Create a map with newsprint and markers that shows where and when crop plants were domesticated. Prepare to report this information to the larger group.

Group #2 - Read "Stone Age Wine" (McGovern, 2003), "Wine Lore" (http://www.frankies-place.com), and "A History of Beer" (http://www.alabev.com/history.htm).
Note that previous hypothesis on the reasons for the advent of agriculture among humans centered around need for food. Dr. McGovern and colleagues propose the Paleolithic Hypothesis.

What is this hypothesis?
According to this hypothesis, why did humans begin to settle in one place to grow crops?
What organisms assisted by breaking down sugars into glucose?
List the multiple purposes for plant sugars in these peoples lives.
Prepare a map on newsprint and prepare an oral account of the history of the origin of agriculture. Include the names of modern nations that occupy this area.

Group #3 - Read "Eastern North America and the Southwest" (Smith, 1995).
When and how did corn (maize) become a food staple in the midwestern US?
What crops had people in this area already domesticated?
Are these high starch sources?
Draw a map on newsprint and prepare to share this information to the larger group.

Group #4 - Read "A Grain of History" (Diamond, 2004).
How was rice brought to the central US?
Prepare a visual aid and oral account of the history of rice cultivation in the region.

Group #5 - Read "Human Population Growth: Lessons from Demography" (Chrispeels and Sadava, 2003).
What effect does the ability to control a food source have on the quality of human existence?
Prepare a visual aid that shows how food supply and other factors work together to form the quality of human existence. Be prepared to share this information to the larger group.

Group #6 - Read the article on Bt rice.
What is Bt rice? Prepare to relate to the group current research and development on rice production.
What is the advantage of Bt rice? The disadvantages?

2. Provide an opportunity for students to examine the relative starch content of a variety of foods.

Provide each group with 2-15 ml conical centrifuge tubes. Instruct students to weigh their tubes and record the weights in milligrams.

With a blender, homogenize a variety of vegetables separately in ddH2O or tap water.

Allow each group to choose two vegetables: spinach, carrots, squash, lettuce, corn (cut fresh off the cob), potatoes, broccoli, beets.

Each group will centrifuge their homogenates in the pre-weighed 15 ml conical centrifuge tubes at high speed in a clinical centrifuge for 10 min.

After 10 min. have students remove their tubes and decant the supernatant.

Direct students to remove any solid tissue with a laboratory spatula, leaving the starch pellet at the bottom of the tube.

Instruct students to reweigh the tubes and subtract the tare to determine the starch content of their vegetable in milligrams.

Record these on the board and ask:

Which are the best food staples?
How does starch content affect value as a food staple?
So what's the big deal about corn?

3. Deliver a minilecture on urban myths of GMO, based on Chrispeels and Sadava (2003).

Lead a discussion on the pros and cons of GMO in the production of genetically modified plants.

4. Instruct students to write an opinion paper on the use of terminator genes in seeds. Emphasize to students that their opinion will not be graded, but that they will be graded on the quality of their defense and elaboration.

 

Resources

Literature Cited

Chrispeels, M.J. and D.E. Sadava. 2003. Plants, Genes, and Crop Biotechnology. 2nd ed. Jones and Bartlett Publishers. Sudbury, MA.561 pp.
Diamond, H. 2004. "A Grain of History." BO420 Ethnobotany, Southeast Missouri State University, Spring 2004.
McGovern, P.E. 2003. Stone Age Wine. Pp. 1-15 in Ancient Wine. Princeton University Press, Princeton, NJ. 365 pp.
Smith, B. 1995. In Search of Origins. Pp 1-13 in The Emergence of Agriculture. Scientific American Library, New York, NY. 231 pp.
Smith, B. 1995. Eastern North America and the Southwest. Pp. 183-206 in The Emergence of Agriculture. Scientific American Library, New York, NY. 231 pp.

SEE SPECIAL DATA ITEMS FOR RESOURCE FILES.

Students will usually obtain additional references or resources
to help answer or explore their questions.

Special Data Items

1. east NA and SW corn.pdf
2. AHistoryofBeer.doc
3. lessonplanearlydevelopment.doc
4. Resource1.doc
5. resource 2.pdf
6. resource 3.pdf
7. resource 4.pdf
8. resource 5.doc
9. RiceDiamondHope.doc
10. WineLore.doc
11. stoneagewine.pdf
12. insearchoforigins.pdf
13. sweetcorn.jpg

 

Student Products

1. opinion papers

Assessment and Evaluation Plan

1. Quiz on embryonic and seed development.
2. Opinion paper
3. Presentation

 

Implementation

LESSON PLANS
EARLY PLANT DEVELOPMENT AND SEED GERMINATION
2@ 1 HR LECTURE/DISCUSSION + 1@ 2 HR LAB

BRIEF OVERVIEW:
DAY 1 - Introduce case, analysis, lecture/discussion on Bt corn and GMO
DAY 2 - World starches, readha dn respond cards, lecture/discussion on germination
DAY 3 - Lab components, assigned readings, lab on starch content

Teaching Aim: To lead students to examine material on early plant development and to use that information to consider current issues regarding GMO, company, government, and consumer responsibility, and ownership of technology. In addition, students will establish and adequately defend an informed opinion on business ethics, responsibility, ownership, and the world food supply.

Session 1: Early Embryonic Development 50 min

1. (5 min) As students enter, pass out case studies (Resource 1). Instruct students to read and fill out the accompanying table, listing any information they know about he subjects in the case study and any questions they might have.

2. (5 min) Open the session by asking students to brainstorm information they know about the topics presented in the case study. Record input on the chalkboard or on a blank MSPpt slide. Next, record questions that students listed in their tables. Explain that in this session, they will learn about early embryonic development in plants and how knowledge of seed development affects world food markets.

3. (5 min) Begin with a minilecture on the history, technology, and sociological issues concern Bt corn usage. Include the following: definition of Bt corn, the bacterial origin of the gene, the purpose of corn refuges, the rate of lateral transfer, the cost of testing to the farmer with pure seed.

Ask: What are some possible social issues surrounding Bt corn?

What is Bt corn?:
http://www.uky.edu/Agriculture/Entomology/entfacts/fldcrops/ef130.htm

Bt = Bacillus thuringiensis - a soil bacterium that produces a toxin that is deadly to some insects. Many strains exist, each with great specificity as to the type of insect it can effect.

http://www.opha.on.ca/ppres/2001-01_pp.pdf

Bt corn refuges:

http://www.uky.edu/Agriculture/Entomology/entfacts/fldcrops/ef128.htm

Protecting Our Food Supply, Public Health Implications of Food Biotechnology:

http://www.opha.on.ca/ppres/2001-01_pp.pdf

One farmer's experience with lateral transfer:

http://www.platformgentechnologie.nl/genetech/thema_incidenten/bioboer.html

Percent of transfer rate:

http://www.gene.ch/genet/2003/May/msg00130.html

"At 40-50 feet away you are probably looking at around 1 percent of corn to be contaminated."
"Seed companies are concerned for purity reasons. They'll accept seeds that are 99.5 percent hybrid X and 0.5 percent Y, but they usually won't accept contamination levels exceeding 1 percent."

Most refuges end up with high transfer because of proximity:

http://www.innovations-report.de/html/berichte/agrar_forstwissenschaften/bericht-29055.html

4. (30 min) Introduce terminator seeds. Pass out a copy of Monsanto's home web page (Resource 2) or visit the page on the internet.
Describe the agribusiness and the money invested in research and development of agricultural products.
Explain that terminator seeds were designed to protect technology behind newly developed hybrids.
a. Using MSPpt or a chalkboard, illustrate and describe the angiosperm lifecycle (Resource 3).
b. Emphasize early embryonic development, including the totipotency of the embryo, with meristematic tissues for all tissues, and the advantage of the endosperm for long-term viability.
c. Highlight the genetic mechanism that allows terminator seeds to work (Resource 4).

5. (5 min) Open the floor to questions and clarification.

Session 2
1. (5 min.) As students arrive, hand out the read and respond card (Resource 5)
. Allow enough time into the lecture for students to complete the activity.
Ask: What is the importance of corn?
On the board, write: the importance of corn.
List their suggestions beneath it.
Next, ask: Are there any food staples besides corn that you could think of?
Create a table similar to the one on resource 5 and fill it in with their suggestions.

2. (5 min.)Ask students to note what these foods have in common. Select corn, rice, beans, squash (Cucurbitaceae species), and wheat for your discussion. Point out that starch is the common component that forms their value as a food staple.

3. (35 min.) Lecture on seed germination veiled in a narrative about seed germination. Cover these subject areas.
a. seed structure
b. endosperm
c. environmental cues for germination
d. hormonal action
e. imbibition
f. embryo uptake
g. glycolysis and respiration

4. (5 min.) On the board, draw a plant cell and an animal cell. To the side, draw one glucose molecule and sketch amylose for quick reference. In the plant cell, illustrate and emphasize photosynthesis as the sugar/starch producing process within the chloroplast. Next, illustrate and emphasize the breakdown of these sugars though glycolysis in the cytoplasm and respiration in the mitochondrion. Show the release of CO2 and the uptake and use of O2. In the animal cell, show the uptake of glucose, glycolysis, and respiration, and the exchange of gases. Emphasize the similarities and the need for glucose. Ask: Does the animal cell have chloroplasts? Explain that plants make their own sugars with light energy, CO2 and electrons from H2O.
Ask: How does the animal cell obtain glucose, then? Illustrate animal consumption of plant tissue.
Ask: What happens to the sugars/starch in the plant tissue when a human consumes it? So what is the big deal about corn or rice? About soy?

Session 3 - Lab Component
1. Divide students into groups. Provide each group with an assignment. In order, reading materials should address these questions:

How and why did humans begin to rely on agriculture for their dietary and medicinal needs?
How did corn and rice become cultivated in the United States?
What effect does the ability to control a food source have on the quality of human existence?

Group #1 - Read "In Search of Origins" (Smith, 1995).
Create a map with newsprint and markers that shows where and when crop plants were domesticated. Prepare to report this information to the larger group.

Group #2 - Read "Stone Age Wine" (McGovern, 2003), "Wine Lore" (http://www.frankies-place.com), and "A History of Beer" (http://www.alabev.com/history.htm). Note that previous hypothesis on the reasons for the advent of agriculture among humans centered around need for food. Dr. McGovern and colleagues propose the Paleolithic Hypothesis. What is this hypothesis? According to this hypothesis, why did humans begin to settle in one place to grow crops? What organisms assisted by breaking down sugars into glucose? List the multiple purposes for plant sugars in these peoples lives. Prepare a map on newsprint and prepare an oral account of the history of the origin of agriculture. Include the names of modern nations that occupy this area.

Group #3 - Read "Eastern North America and the Southwest" (Smith, 1995). When and how did corn (maize) become a food staple in the midwestern US? What crops had people in this area already domesticated? Are these high starch sources? Draw a map on newsprint and prepare to share this information to the larger group.

Group #4 - Read "A Grain of History" (Diamond, 2004). How was rice brought to the central US? Prepare a visual aid and oral account of the history of rice cultivation in the region.

Group #5 - Read "Human Population Growth: Lessons from Demography" (Chrispeels and Sadava, 2003). What effect does the ability to control a food source have on the quality of human existence? Prepare a visual aid that shows how food supply and other factors work together to form the quality of human existence. Be prepared to share this information to the larger group.

Group #6 - Read the article on Bt rice. What is Bt rice? Prepare to relate to the group current research and development on rice production. What is the advantage of Bt rice? The disadvantages?

2. Provide an opportunity for students to examine the relative starch content of a variety of foods.
Provide each group with 2 -15 ml conical centrifuge tubes. Instruct students to weigh their tubes and record the weights in milligrams. With a blender, homogenize a variety of vegetables separately in ddH2O or tap water. Use: spinach, carrots, squash, lettuce, corn (cut fresh off the cob), potatoes, broccoli, beets. Allow each group to choose two vegetables. Each group will centrifuge their homogenates in the pre-weighed 15 ml conical centrifuge tubes at high speed in a clinical centrifuge for 10 min. After 10 min. have students remove their tubes and decant the supernatant. Direct students to remove any solid tissue with a laboratory spatula, leaving the starch pellet at the bottom of the tube. Instruct students to reweigh the tubes and subtract the tare to determine the starch content of their vegetable in milligrams. Record these on the board and ask: Which are the best food staples? How does starch content affect value as a food staple? So what's the big deal about corn?

3. Deliver a minilecture on urban myths of GMO, based on Chrispeels and Sadava (2003). Lead a discussion on the pros and cons of GMO in the production of genetically modified plants.

4. Instruct students to write an opinion paper on the use of terminator genes in seeds. Emphasize to students that their opinion will not be graded, but that they will be graded on the quality of their defense and elaboration.

Course name:
Plant Biology
Likely sequence in syllabus:
after reproduction /seed germination
Time during term:
spring
Duration:
week
Setting:
Classroom and Lab
Students in course:
sophomore level
Collaborative elements:
Groups
Additional notes:

 

Credits

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