We scheduled and participated in several Internet Research Sessions with our Library Media Specialist to find information concerning different ways of producing healthy foods. Coupled with information supported by scientific journals (see references in Adult Bibliography), and classroom discussion, our students were able to discover the following information. Our findings sparked interesting viewpoints and debate.
What impacts the growth of healthy crops and how do farmers and scientists help to make it better?
Many factors impact the growth of healthy crops. Weeds, plant diseases, and insects can be harmful to crops, threatening their healthy growth and development. Many farmers and scientists work together to combat this problem. Today, many farmers control pests by using chemicals called pesticides and herbicides. Although these chemicals are useful, they can pollute our environment if they are not used properly. They can also cause health problems for people and animals.
**These activities are the result of questions and discoveries raised by the students.
One way that some farmers and scientists are attempting to combat this problem is through organic farming. Natural substances rather than chemicals are used to fertilize soil and control pests. Many farmers conduct organic farming by rotating their crops each year. Crop rotation helps fight against disease and insect pests in a special way. Usually, if certain crops are planted and grow in the same field each year, diseases and insects that are attracted to those plants will continue to flourish. When crops are rotated, the same plants are unavailable, and often diseases and insects die out. Organic farming is a good alternative, but it is a long process.
Some scientists and farmers believe that they can make better food products by transferring genes from one living thing to another. They use the good qualities of those genes to enhance food products. This process is known as genetic engineering. Here are a few examples.
Tomatoes are very perishable, particularly when transported from one portion of the country to another. After fruit ripening, they could mold and become rotten before they are delivered to their place of destination. (Some tomatoes have been genetically altered so that ripening is considerably delayed. As a result, we can transport tomatoes when they are hard and green, and allow them to ripen in our homes.) They could also be frost bitten if grown in climates where temperatures are not conducive to tomato growth. How could we help tomatoes stay fresh when transporting them from one region of the U.S. to another locale? How could we prolong their shelf life? Some scientists have found a gene in Arctic flounder that helps that species of fish survive in freezing waters. These scientists have experimented with this gene and have been able to transfer and place it in the genes of tomato cells. These combined cells grow into tomato plants. The results: tomatoes that resist the cold have been created. The tomato has been biogenetically engineered. Many of these scientists say that biogenetic engineering will not affect those who consume tomatoes.
Some food crops, like potatoes, cabbage, and lettuce are attacked and sometimes harmed or destroyed by insects. In an effort to combat this problem, scientists have created potatoes, cabbage, and lettuce that have been biogenetically engineered to fight against insect infestation. An insect repellant gene has been transferred into the plants, and they make the insecticide themselves. This strengthens the plants insect resistance while reducing the need for insecticide use.
What are transgenic crops, and how are they created?
Transgenic crops are crops that have undergone genetic modification. Let’s take a simplified look at the process. Biotech scientists are able to isolate and insert genes that have a desirable characteristic from one living thing into another. A desirable genetic trait might be to enhance nutritional value, pesticide and/or herbicide resistance, or the ability to ward off plant viruses. The host plant into which the gene is transferred soon takes on that desired trait. That crop is a transgenic crop.
Do genes have to be transferred from the same species or organism?
No. Genes can be transferred from totally unrelated species or organisms, for example, that gene that helps Arctic salmon endure cold being transferred into a tomato plant.
What types of edible plants have been genetically engineered and why?
Broccoli, melons, raspberries, and tropical fruits, peas, peppers, and tomatoes have been genetically modified to control ripening. This helps to improve shelf life and the quality of the food when it arrives in food stores like Shaw’s and Stop ‘N’ Shop. It also prolongs the “freshness and durability of the food”, particularly in tomatoes.
Corn, cabbage and other related vegetables in this family, potatoes, lettuce, coffee and apples have been genetically modified to create insect resistant species. As a result, these vegetables are inherently able to protect themselves against harmful insect pests, and the need for insecticide use is reduced.
Soybeans, corn, tomatoes, wheat, and rapeseeds used in canola oil have been genetically modified to be herbicide tolerant. These transgenic plants can survive herbicide applications that will kill all weeds.
Corn, sunflowers, soybeans, and other plants have been genetically modified to enhance nutritional value. Vitamins, amino acids, and other nutrients make these plants more nutritional.
Many plants like potatoes, cantaloupe, squash, cucumbers, corn, soybean, and grapes are subject to plant viruses. These plants have undergone genetic modification for viral resistance. Because of genetic modification, plant viruses are reduced and the use of insecticides minimized.
Have all of the plants noted above been genetically modified in America?
No, they have not. But, since 1995, millions of acres of transgenic crops have been planted in our country.
Do all people believe that transgenic crops are healthy?
Some peopleparticularly consumers (people who purchase and use these products)--disagree with scientists and farmers who use genetically engineered farming techniques. They believe that more research needs to be conducted, that people and animals may be harmed by long-term consumption of such foods. Some consumers are fearful that transferring genes can result in allergic reactions in humans. This viewpoint has been raised because a small number of individuals who have eaten genetically engineered soybean-based products have had allergic reactions to these foods. Some people believe that scientists are making foods poisonous, harmful, and unsafe when they introduce insect resistant, herbicide tolerant, and viral resistant genes to specific plants.
Many vegetarians and religious groups who are restricted in eating certain foods believe that because a fish gene has been implanted in a tomato, it is hard to determine whether the GM tomato is a “vegetable.”
Important to know, however, is that the genetic modification of foods is no new phenomena. All existing crops, for example, have been “naturally engineered” by bacteria that move genes around without human intervention. The cells of Agrobacterium are even used today to accomplish genetic engineering of crops. (Agrobacterium--a naturally occurring bacterium that accomplishes genetic engineering on its own, without human intervention-- has a plasmid (circular piece of DNA) that it can transfer to plant cells, conferring new genetic traits. Scientists can also splice genes that we want [like insect resistance] into such plasmids and transfer them into plants.)
Can herbicides and pesticides be absorbed by plants? If they can, can’t those plants be harmful to humans and animals?
This question was overwhelmingly repeated and sparked debate among our young learners. Many conjectured that the answer to both was “yes.” So the children could visually grasp that plants have the ability to absorb chemicals from their environment, we conducted the following experiment:
Activity 1: Can Harmful Chemicals Be Absorbed?
*six beakers of water: two labeled “organically grown”, two labeled “pesticide”, two labeled “herbicide”
*six leafy-tipped celery stalks
*red and blue food coloring
*plastic knives (one per student)
*magnifying glasses (one per student)
*Science journal (with Page Headings Hypothesis, Materials, Procedure, Observations, Results, Application) to record our findings
Note: The children were advised that because we could not actually use hazardous chemicals like pesticides and herbicides in class (a New Haven Public School mandate), we would use colored water to represent these chemicals.
(1) Pour 2” inches of water into each beaker. Leave one beaker color-free and label it “organically grown”.
(2) Add 10 drops of red food coloring to two of the beakers labeled “pesticide”. Stir until the water therein is completely red.
(3) Add 10 drops of blue food coloring to two of the beakers. Stir until the water therein is entirely blue. Label these beakers “herbicides.”
(4) Place two celery stalks in each beaker. Sit each container on the window ledge over night.
(5) Next day, examine stalks. Evaluate outcome.
Findings. The following day, the children observed that the celery stalks labeled “pesticide” and “herbicide” had turned red and blue respectively. The ones placed in uncolored water remained green. The children were amazed that the stalks had changed colors, noting the celery “drank up” the water. The children were each given an opportunity to slice a small piece of celery from each stalk. Using their magnifying glass, they further discovered that the veins within the stalk took on the color of the liquid. They deduced that if plants “drink up water that contain nutrients from the soil” and that soil contains herbicides and/or pesticides, those chemicals could become part of that food. If we eat the plants or other animals that eat these plants, those chemicals might in turn enter our body and could be harmful to humans and other animals.
Each child recorded the outcome of the experiment in his/her Science Journal. Many additionally noted that:
*farmers and scientists should be careful about using pesticides and herbicides on foods
*people must be careful when selecting foods to eat
*we should wash foods before we eat them or cook them thoroughly
*we should eat less foods that have been grown using pesticides and herbicides.
The previously noted experiment sparked a lot of discussion and an additional question:
Can plants that have pesticide resistant genes be harmful to people and animals too?
The answer is “yes, if the gene causes the plant to produce its own pesticide, that is in turn toxic to humans. Just as in the case of sprayed pesticides and herbicides that are taken up by that plant, the same holds true for transgenic versions.
This response yielded a large number of students asking, “So, which foods are best to eat?”
Activity #2: Opinion Poll: Which Foods Are Best To Eat
This activity serves as a unit review. It also serves as a Language Arts/Social Development/Social Studies/Math component of this section defined as follows:
Language Arts. Students will use oral language to organize and express ideas. Logical thinking will be used to support expressed ideas. Role play will be used to assist in creatively expressing ideas. Findings will be noted on paper, reinforcing the connection between the written and spoken word.
Social Development. Sharing, taking turns, coming to consensus, and communicating effectively is a sophisticated skill for young learners. This interaction serves as a challenge and positive reinforcement to problem solving and sharing through social interaction and verbal communication.
Social Studies. Children will learn that within our society, there are consumers and producers, that these individuals and lobbyist groups can voice concerns and discuss issues. This role play activity will help them recognize that opinions count.
Math. Graphing/numeric comparison will be used to record and evaluate student preference.
You will need:
a camcorder (optional)
chart paper to graph results
a raw potato
*Children come to group on the rug and are seated in a circle. Students will take turns in speaking by passing the potato. Whoever is holding the potato has the floor.
*Each will be given a choice to pretend they are a farmer, scientist, or consumer.
*After making their selection, all class members are given the opportunity to share their point of view. (Model the responses, i.e., “Hello. My name is _____________________, and I am a _____________________. I believe that ___________________ foods are the best to eat because ________________________________.)
* All participants must support their viewpoint.
Which is best, to eat:
*foods that have been chemically treated with pesticides and herbicides
*foods that have been genetically engineered to ward off insect and plant pests
*foods that have been organically grown
Based on previously explored information, my students were aware of the fears that some people have concerning the use of GM and chemically treated plants (potatoes, tomatoes, corn…) and advocacy views held by many in the scientific and agricultural field. That prior knowledge served as a springboard for opinions.
The children came up with fascinating, valid responses. These key views were consolidated and recorded as follows:
Scientist Views. We should grow genetically engineered foods because they become resistant to diseases and pests, may have more vitamins and minerals to help people stay healthy, and can produce more food to feed our increasing population. We don’t think there will be a lot of problems growing genetically engineered foods.
Farmer Views. We should grow fruits and vegetables and spray them with pesticides to keep insects away. We should use herbicides to get rid of weeds. People can always wash the pesticides and herbicides off before they eat the foods. That way, they will be safe to eat.
Consumer Views. We should eat foods that are organically grown because nothing has been done to them. We should not eat foods that are genetically engineered or sprayed with pesticides and herbicides because we might become sick.
Graphing Our Findings. After listening, recording, and consolidating responses, students were asked to think individually about the presented views regardless of their previously assumed roles. They were asked to select only those viewpoints that they agreed with most. We tallied the responses, which were somewhat sophisticated: 8 agreed with Scientist Views; 2 with the Farmers View, and 11 with the Consumers. The majority agreed that long-term use of pesticides and herbicides on plants, whether sprayed on or genetically engineered, would be harmful risk for the consumer.
A graph was prepared based regarding the responses. The children were not only able to identify and compare numbers or recognize who had the most votes. They too noted that people don’t always agree on the same issues. Sometimes we have to work together to make things happen. (They also agreed that the majority rules, and this time, consumers were the winners.)