neered foods.1 However, not all genetically engineered foods are equal. To date, the majority of genetically engineered plants that have been approved for commercial use contain genetic changes that have to do with herbicide or pesticide resistance. They are classified as agronomic because their main purpose is to make the growing of those crops less costly (farmers save money by losing fewer plants to insect damage or by not having to buy and apply as many herbicides).
But future generations of genetically modified crops are being developed to contain pharmaceutically active proteins. A pharmaceutically active protein is simply a drug, such as a vaccine or medicine. Although the biology behind creating those agronomic and pharmaceutical transgenic plants is similar, the consequences of the changes may be very different. For example, the health effects on humans who consume a plant that contains a pharmaceutical transgene can potentially be quite different from the health effects on humans who consume a plant that contains an agronomic transgene.
Another issue that must be considered when using plants to make pharmaceutically active proteins is the use of food crops (such as corn, soybeans, rice) versus nonfood crops (such as tobacco).2,3 Food crops offer several advantages over nonfood crops when creating pharmaceutical transgenic plants, such as the ability to eat the plant directly and the fact that proteins are more stable and easier to store for long periods in food plants such as grains. However, the use of nonfood crops has the benefit of potentially limiting unwanted human exposure to the transgenes because they are not consumed directly by humans.
Endnotes:
1. K. Hopkin, “The Risks on the Table, Scientific American, April 2001, p. 61.
2. Michelle Marvier,. “Pharmaceutical Crops Have a Mixed Outlook in California,” California Agriculture 61, no. 2 (2007): 59–66.
3. M. Marvier and R. C. Van Acker, “Can Crop Transgenes Be Kept on a Leash?” Frontiers in Ecology and the
s t u d e n t P a g e
100 project learning tree Exploring Environmental Issues: BioTechnology ©AmericAn Forest FoundAtion
rubric for Presentation
Does Not Meet
Expectations Meets Expectations Exceeds Expectations Score
Introduction
(title and outline) 0 pointsq Title or outline or both do not accurately reflect contents of presentation.
q Title or outline or both are missing.
12 points
q Title and outline mostly reflect contents of presentation. q Title and outline are
present.
2–4 points
q Title and outline accu- rately reflect contents of presentation. q Title and outline are
present. Content 0 points q Information provided is inaccurate. q Information is not explained clearly. q Terminology is not defined. 1–4 points q Information provided is mostly accurate. q Information provided is mostly explained. q Some terminology is defined. 4–8 points q Information provided is accurate. q Information presented is clearly explained. q All terminology is clearly defined. Visuals 0 points
q Text is too small to be read.
q Pictures and graphics are not used.
2–3 points
q Text is mostly effective. q Use of pictures and
graphics mostly enhance presentation.
3–5 points
q Text is large enough to be read by entire audience.
q Use of pictures and graphics enhances audience’s understand- ing of the content. Grammar and
spelling
0 points
q There are more than two grammar and spelling errors.
1 points
q There are fewer than two grammar and spelling errors
3 points
q There are no grammar or spelling errors. Presentation
style (Include a final slide that lists major contributions of each group member) 0 points q Contribution of all group members is unclear.
q Diction and voice level do not engage audi- ence.
2–3 points
q Most members of the group contributed to presentation.
q Diction and voice level are mostly effective at engaging audience.
3–5 points
q Each member of the group contributed to the presentation. q Diction and voice level
engage the audience.
Objectives:
Students will discover the ways in which botanists and forest
scientists have manipulated trees to promote the expression of desired characteristics.
Students will research the detrimental effects of an introduced
fungus on the distribution of the American chestnut. Students will learn how to manipulate DNA in a lab setting
while answering ecological questions.
Students will debate the merits of different methods of
forest management practices, given today’s traditional and biotechnical options.
Students will perform a species abundance and diversity
survey to anticipate changes that may occur if any one species becomes diseased.
Assessment Opportunities:
Student Page: Informational Brochure on Tree Improvement
Techniques can be used to determine how well each student understands the traditional and modern methods of tree improvement.
The lab results and Student Page: DNA Extraction and Gel
Comparison of Cut DNA—Lab Experiment can be used to assess the student’s understanding of DNA manipulation. Student Page: Peer Review of Informational Brochures and
Student Page: Strength of Argument can be used to evaluate the development of each student’s study skills.
Oral and visual presentations of a postdisease map to the
members of each student’s group can be used to indicate each student’s comfort and competency with mapping and survey skills.
Subjects: Biology, AP Biology, Ecology, Environmental Science,
AP Environmental Science, Forestry, Social Studies
Concepts:
1.4, 2.3, 3.6, 3.7, 4.5, 5.4, 5.5
Skills: Analyzing, Comparing and Contrasting, Concept Forming,
Concluding, Debating, Discussing, Evaluating, Generalizing, Identifying Relationships and Patterns, Interpreting, Observing, Ordering and Arranging, Predicting, Representing, Researching, Synthesizing and Creating
Materials:
For the class: an overhead projector, copies of a map of the
United States on overhead transparency sheets for each group, two different colors of overhead markers
For each group: 20 milliliters (ml) of liquid dish soap, 10 grams of
table salt, 400 ml distilled water, one 500-ml flask, a fingerprint DNA kit (enough supplies for each group), including three types of sample DNA, restriction endonucleases (or precut DNA), a garose gel, a gel stain, a gel electrophoresis rig and power supply to run the fingerprint results from each lab group or to run a single example gel for use by the entire class, graph paper, one field guide to trees of North America (or trees in your specific region) for each lab group (if you have an area with many ornamental or introduced trees, you may need to create your own field guide)
For each student: copies of student pages, computers with Internet
and Microsoft Office Publisher, a CD of the Charlie Chestnut slide show from the American Chestnut Foundation, a computer and projector to show the information on the CD to the class (or if you have Internet access, the slide show can be viewed at www. charliechestnut.org), one strawberry, one small Ziploc® (or similar)
plastic bag, one 50-ml disposable tube with a cap, one 15-ml
disposable tube with a cap, one 15-centimeter x 15-centimeter square of four-ply cheesecloth, 5 ml of ice-cold 95 percent ethanol, one toothpick-diameter wooden stick long enough to reach the bottom of the 15-ml tube, one 1-ml microcentrifuge tube
Time Considerations: Preparing the Activity
Part A: 15 minutes Part B: 15 minutes Part C: 30 minutes Part D: 15 minutes Part E: 15 minutes Part F: 30 minutes
Doing the Activity:
Part A: Two 50-minute periods Part B: One 50-minute period Part C: Three 50-minute periods
Part D: Two 50-minute periods Part E: Two 50-minute periods, plus homework
Part F: Three 50-minute periods