The Debate over Genetically Modified Foods
Addresses:
 SC.912.L.16.10: Evaluate the impact of biotechnology on the individual, society and the
environment, including medical and ethical issues.
 SC.912.L.16.9: Explain how and why the genetic code is universal and is common to almost all
organisms.
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Rice with built-in Vitamin A that can help prevent blindness in 100 million children suffering
from Vitamin A deficiency;
A tomato that softens more slowly, allowing it to develop longer on the vine and keep longer
on the shelf;
Potatoes that absorb less fat when fried, changing the ever-popular french fries from junk food into a more nutritional
food;
Strawberry crops that can survive frost;
An apple with a vaccine against a virus that causes childhood pneumonia.
2 These are some of the benefits promised by biotechnology. The debate over its benefits and safety, however, continues. Do we
really need to fear mutant weeds, killer tomatoes, and giant corn and will the benefits be delivered?
Conventional Breeding versus Genetically Modified (GM) Crops
3 For thousands of years farmers have used a process of selection and cross breeding to continually improve the yield and quality of
crops. However, traditional breeding methods are slow, requiring intensive labor: while trying to get a desirable trait in a bred
species, undesirable traits will appear and breeders must continue the process over many generations until all the undesirable traits
are bred out.
4
In contrast, GM organisms are given one specific gene or a few genes together; therefore, the organism acquires the desired trait
within a single generation. However, this technology can be unpredictable and some scientists believe it can produce potentially
dangerous results unless better testing methods are developed. Nonetheless, GM plants are now grown on about 130 million acres
in 13 countries, including Argentina, Canada, and Germany. In 2001, 3.6 million acres were used for GM crops in the U.S. More than
60% of all processed foods in the U.S. contain ingredients from GM soybeans, corn, or canola. 1
5 Unlike with traditional breeding approaches where the species must be the same or very closely related, GM crops can receive genes
from distant species, even bacteria and viruses. A typical example of a GM crop in the market in Australia is cotton known as
Ingard™.6 Scientists inserted a naturally occurring gene from a soil bacterium known as Bacillus thuringiensis into the cotton which
renders the cotton resistant to the heliothis caterpillar, a major threat to the cotton industry. In this example, an appropriate and
selected gene was inserted into the cotton from a bacteria rather than being inherited from a similar species as in traditional
breeding approaches.10
Benefits: one side of the debate
Economical
6 GM supporters tell farmers that they stand to reap enormous profits from growing GM crops. Initially, the cost is high but money is
saved over time in lower production costs, fewer pest problems, reduced use of pesticides, and better yields. To produce GM crops,
modern biotechnology is used which requires highly skilled people and sophisticated and expensive equipment which increases the
cost of the seed.7
Herbicide/Pesticide-resistant crops
7 So what other advantages do GM crops hold for farmers? GM crops can be produced to be herbicide resistant. This means that
farmers could spray these crops with herbicide and kill the weeds, without affecting the crop. In effect, the amount of herbicide
used in one season would be reduced, with a subsequent reduction in costs for farmers and consumers. For Ingard™ cotton, pest
resistance was built into the cotton, hence reducing and even removing the need for pesticides, which are not only expensive but,
more importantly, harmful to the environment.
Environmentally Hardy
8 Biotechnology companies are even experimenting with crops that can be genetically modified to be drought and salt-tolerant or less
reliant on fertilizer, opening up new areas to be farmed and leading to increased productivity.
Better quality animal products
9 Even animals can be genetically modified to be leaner, grow faster, and need less food. They could be modified to have special
characteristics, such as greater milk production in cows. These modifications again lead to improved productivity for farmers and
ultimately lower costs for the consumer. Modified crops could perhaps prevent outbreaks such as foot and mouth disease, which
has devastated many farmers and local economies. No such products have been released to date; however, some are under
consideration for release. For example, GM salmon, capable of growing almost 30 times faster than natural salmon, may soon be
approved by the FDA (Food and Drug Administration) in the U.S. for release into open waters without a single study on the impact
on human health or the environment.5
10 The following are some examples of food plants that are undergoing field trials: 10
 apples that resist insect attack
 bananas free of viruses and worm parasites
 coffee with a lower caffeine content
 cabbage that resists caterpillar attacks
 melons that have a longer shelf life
 sunflowers that produce oil with lower saturated fat
Risks: the other side of the debate
Environmental damage
11 One problem with GM crops is that there is little known about what effect they will have in, say, 20 years time. The genetic structure
of any living organism is complex and GM crop tests focus on short-term effects. Not all the effects of introducing a foreign gene into
the intricate genetic structure of an organism can be tested.
12 Then there is always the possibility that we may not be able to destroy GM crops once they spread into the environment. In Europe,
for example, a strain of sugar beet that was genetically modified to be resistant to a particular herbicide has inadvertently acquired
the genes to resist another.7 This was discovered when farmers attempted to destroy the crop in Britain, France and the
Netherlands, where it was being tested, and 0.5% of the crop survived.7 More noxious herbicides had to be used to remove the
remainder of the weeds. What if this herbicide resistance passed on to weeds?
Risk to food web
13 A further complication is that the pesticide produced in the crop may unintentionally harm creatures. In Britain, a native farm bird,
the Skylark, was indirectly affected by the introduction of GM sugar beets designed to resist herbicides. In planting this crop, the
weeds were reduced substantially. However, since the birds rely on the seeds of this weed in autumn and winter, researchers expect
that up to 80% of the Skylark population would have to find other means of finding food. 4
14 GM crops may also pose a health risk to native animals that eat them. The animals may be poisoned by the built-in pesticides. Tests
in the U.S. showed that 44% of caterpillars of the monarch butterfly died when fed large amounts of pollen from GM corn. 8
Relatedly, what happens when pests develop resistance to the pesticides used?
Cross-pollination
15 Cross-pollination is a concern for both GM crops and conventional breeding, especially with the more serious weeds that are closely
related to the crops. With careful management this may be avoided. For example, there is a type of maize that will not breed with
other strains and scientists are hoping that it could help to prevent cross-pollination.3 Genetic modification to herbicide resistant
crops could insert the gene that prevents the problem. The number of herbicide-tolerant weeds has increased over the years from a
single report in 1978 to the 188 herbicide-tolerant weed types in 42 countries reported in 1997.6 They are an ever-increasing
problem. Will genes from GM plants spread to other plants, creating superweeds and superbugs we won’t be able to control?
GM mix-ups
16 Humans can inadvertently eat foods that contain GM products meant as animal feed, i.e., crops modified for increased productivity
in animals. This happened in the U.S., where traces of a StarLink GM crop, restricted for use only in feed, were found in taco shells.2
Apparently no one became ill but other such occurrences may lead to health problems.
Allergies and toxins
17 Very little scientific information exists about the risk of GM food on human health. One major report by Dr. Arpad Pusztai, published
on this web site, explains how GM foods could trigger new allergies and contain toxins that may be harmful. 9 However, a document
published by the World Health Organization 11 shows no adverse events to date.
Disease
18 Another concern is disease. Since some crops are modified using the DNA from viruses and bacteria, will we see new diseases
emerge? What about the GM crops that have antibiotic-resistant marker genes? Marker genes are used by scientists to determine
whether their genetic modification of an organism was successful. Will these antibiotic-resistant genes be transferred to
microorganisms that cause disease? We already have a problem with ineffective antibiotics. How then will we develop new drugs to
fight these new superbugs?
Conclusion
20 Proponents of GM crops claim that advantages may be many, such as:
 improved storage and nutritional quality
 pest and disease resistance
 selective herbicide tolerance
 tolerance of water, temperature and saline extremes
 improved animal welfare
 higher yields and quality to feed an ever increasing global population
21 While it is not possible to make general statements on the safety of all GM foods, to date, no adverse health effects caused by
products approved for sale have been documented.11 Although there is now broad scientific consensus that GE crops on the market
are safe to eat12, some scientists and advocacy groups such as Greenpeace and World Wildlife Fund call for additional and more
rigorous testing before marketing genetically engineered food. Living organisms are complex and tampering with their genes may
have unintended effects.
(This article was heavily edited and altered for clarity and utility with the CIS Model by Troy Suarez. Please refer to the original article for reference
http://www.actionbioscience.org/biotech/sakko.html?print. This article has a 1400L).
Kerryn Sakko is an undergraduate student at Adelaide University, Australia, studying for a double degree in chemical engineering, mathematics and
computer science. In 2001, she represented Australia, with 19 other students from around the country, at the APEC Youth Science Forum held in
Singapore. © 2002, American Institute of Biological Sciences.
References
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13.
Ackerman, Jennifer. 2002. “Food: How Safe? How Altered?” National Geographic, May issue.
Boyce, Nell. 2000. “Taco Trouble.” New Scientist: Vol. 169, No. 2259, 7 October.
Boyce, Nell. 2000. “A Breed Apart.” New Scientist: Vol. 168, No. 2261, 21 October.
Firbank, Les E. and Frank Forcella. 2000. “Genetically Modified Crops and Farmland Biodiversity. Science: Vol. 289, No. 5484, 1 Sept.
Friends of the Earth. 2002. “Petition to President Bush: Don’t Turn Your Back!”
Gene Technology Information Service provided by Biotechnology Australia in partnership with the University of Melbourne
Gene Technology in Australia website. http://genetech.csiro.au/. Accessed 6/02.
Biotechnology Australia website. http://www.biotechnology.gov.au. Accessed 6/02.
Pusztai, Arpad. June 2001. “GM foods: Are they a risk to animal/human health?” http://www.actionbioscience.org/biotech/pusztai.html. Accessed 6/02.
National Centre for Biotechnology Education website. http://www.ncbe.reading.ac.uk/. Accessed 6/02.
20 questions on genetically modified foods. World Health Organization. http://www.who.int/foodsafety/publications/biotech/20questions/en/ Accessed 8/12.
NRC. (2004). Safety of Genetically Engineered Foods: Approaches to Assessing Unintended Health Effects. National Academies Press.
Le Curieux-Belfond O., Vandelac L., Caron J., Seralini G.E. (2009). "Factors to consider before production and commercialization of aquatic genetically modified
organisms: the case of transgenic salmon". Env. Sci. Policy 12 (2): 170–189
CIS Unit
The Debate over Genetically Modified Foods
(9th and 10th grade Biology)
 SC.912.L.16.10: Evaluate the impact of biotechnology on the individual,
society and the environment, including medical and ethical issues.
 SC.912.L.16.9 Explain how and why the genetic code is universal and is
common to almost all organisms.
CIS Lesson
The Debate over Genetically Modified Foods
1. Hook Engage: http://www.npr.org/2011/10/31/141816460/visualizing-how-a-population-grows-to7-billion
2. Question #1
Predict the risks and benefits of using genetically modified organisms.
3.
Pass out article
4. Define vocabulary
a.
b.
c.
d.
Deficiency
Biotechnology
Conventional
Acquires
e.
f.
g.
h.
Renders
Sophisticated
Herbicide
Pesticide
i.
j.
k.
l.
Saturated
Intricate
Inadvertently
Noxious
m. Crosspollination
n. Maize
o. Proponents
5. Text-marking
R = Risk of Genetically Modified Organisms
B = Benefits of Genetically Modified Organisms
6. Question #2
What are the risks and benefits of using genetically modified organisms?
7. Note-taking: What are the greatest challenges to those wishing to ban GMOs?
8. Vote
According to what you read in the text(s), which is the greatest challenge to those wishing to ban
GMOs?
Individual
Group
Recount Individual
Monetary benefits
Health benefits
Inconclusive research
with lots of unknowns
Food
demand/shortages
around the world
9. An individual representing each position presents a persuasive argument in favor of their position.
A recount is conducted to allow student to change their vote.
10. Question #3
You are a politician running for office and you must take a stand either for or against the use of
GMOs. Construct a letter detailing your position to your constituency. Lay out your position with a
thesis statement that is supported with evidence from the provided text. Feel free to bring in
additional research from other sources (be sure to cite those sources; 4 to 5 paragraphs).
#1 Predict the risks and benefits of using genetically modified organisms.
#2 What are the risks and benefits of using genetically modified organisms?
The Debate over Genetically Modified Foods
Vocabulary
a. Deficiency: A lack or shortage
b. Biotechnology: The exploitation of biological processes for industrial
and other purposes
c. Conventional: what is generally done or believed.
d. Acquires: to get or obtain
e. Renders: to make
f. Sophisticated: high degree of complexity
g. Herbicide: chemical that kills weeds
h. Pesticide: chemical that kills pests
i. Saturated: can hold no more
j. Intricate: very complicated and detailed
k. Inadvertently: without knowing or intention
l. Noxious: harmful or poisonous
m. Cross-pollination: transfer of pollen from one flower to another
n. Maize: corn
o. Proponents: supporters
Directed Note-Taking
Directions: Record notes containing the most important information relevant to the guiding question.
The Debate over Genetically Modified Foods
(Text is handout)
Guiding Question: What are the greatest challenges to those wishing to ban GMOs?
Do your questions pertain to any of the categories to the right? If yes, please put a check.
Check Relevant Categories
Page/
Paragraph#
Notes
Monetary
benefits
Collaborative Work:
After completing your chart, be prepared to compare your notes with others.
Health
benefits
Inconclusive
research
Food
demand /
shortages
Question Generator
Directions: Go back through the text and find words, phrases or statements that create questions in your mind. Discuss
these questions in your group, and then document your group’s questions below.
The Debate over Genetically Modified Foods
Page/
Paragraph#
Notes
Monetary
benefits
Collaborative Work:
After completing your chart, be prepared to compare your notes with others.
Health
benefits
Inconclusive
research
Food
demand /
shortages
Directions: Write your answer to the question using information you learned in this unit. Be sure to use information
from the text to justify your answer. Be sure to use complete sentences and correct punctuation and grammar.
#3 You are a politician running for office and you must take a stand either for or against GMOs.
Construct a letter to your constituency detailing your position. You must layout your position with a
thesis statement that is supported with evidence from the provided text. Feel free to bring in
additional research from other sources (be sure to cite those sources). Your position statement must
be at least 4 paragraphs long.
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