Presentation on theme: "Are these claims supported by evidence?"— Presentation transcript:
1 Are these claims supported by evidence? Examples of GM FoodAre these claims supported by evidence?Let’s take a look into some examples of GM food!
2 Example 1: GM maizeAbout 7% of the world’s maize (sweet corn) production is lost to a pest called the European corn borer.The larvae live inside the maize stalk.Pest control is not efficient. Large amounts of pesticides are used.The cost of growing maize increases.Notes to teachers:- 7% of the world maize production worth approximately US$ 2 billion.European corn borer is a moth which larvae live inside the maize stalk. Even through a large amount of pesticide are being used to control the pest, the results are not satisfactory.The use of pesticides increases the cost of growing maize and also causes damage to the environment
3 causes losses to farmers the environment the economy Notes to teachers:The use of pesticides increases the cost of growing maize and also causes damage to the environment.The corn borer causes US$2 billion loss.
4 A gene extracted from a soil bacterium is inserted into maize Bt proteinThe GM maize can produce a protein called Bt protein.When the corn borer larvae eat this protein, their intestinal walls are damaged, causing them to die of starvation.Notes to teachers:Bt protein is normally produced by a soil bacterium Bacillus thuringiensis.
5 The cost is lowered, the crop yield increases. GMbenefitsThe cost is lowered, the crop yield increases.Less maize is lost.Less pesticide is used.Notes to teachers:- GM maize benefits the consumers by lowering the cost of production.Consumers get better quality and more maize
6 Example 2: GM riceGM rice has a higher crop yield (greater weight of rice per plant).Who benefits?Farmers, consumers, economyNotes to teachers:The content of this example has been gone through in article 1 in the worksheet.Teachers can skip the slides or use them to explain article 1.
7 Rice is the main carbohydrate source in many countries. GM rice increases food supply thus may reduce food shortage.Who benefits?People suffering from hunger or in poverty(rice may be cheaper)
8 Golden rice A new GM rice – golden rice, rich in pro-vitamin A (a precursor of vitamin A)People in developing countries suffer from vitamin A deficiency leading to blindnessGolden rice may solve the problem of vitamin A deficiency in developing countries.Notes to teachers:Golden rice is a GM rice which contains higher amount of pro-vitamin A (beta-carotene). People consuming the rice can get more vitamin A.Rice is a staple food in poorer countries. By increasing the amount of pro-vit. A in rice, the deficiency of vitamin A (night blindness) could be solved.Golden rice is yellow in colour.Recent research has revealed that people will need to consume 12 times more rice than normal to satisfy the minimum daily adult requirements of Vitamin Areference:A question raised: Does golden rice really help?
9 Are GM foods safe enough? Bad news!A protein in a new variety of GM rice (Bt rice) may cause allergy in humans (NB: this is NOT “golden rice”)Are GM foods safe enough?
10 GM foods are supposed to be assessed by each different country before it is allowed onto the market thereGM foods are usually tested for their toxicity and whether or not they cause allergyApproved GM foods are therefore not likely to cause risks to human healthNotes to teachers:- The standard in assessing GM food varies between countries.
11 But….. The first GM food was marketed only in 1994. Long term effects on human health cannot yet be assessed.Laboratory animals don’t live as long as humans doAnimal tests can’t pick up small effects on intelligence or personality (brain functions)Trials for food safety of GM crops are often carried out by the companies that have developed them, not by independent researchers.Notes to teachers:Press released by Greenpeace: “Illegal GE rice contamination spreads to major Chinese city”link:However recently, illegal GM rice (without approval) has been discovered in China by Greenpeace(Is this food safe?
12 Moreover…. Some GM food have antibiotic-resistant marker genes Why? The desirable gene may be transferred WITH an antibiotic-resistance gene.By testing the modified organisms with antibiotics, scientists can tell whether the desired gene has been successfully inserted into the “new” organism.Notes to teachers:(1) antibiotic-resistant marker gene:insert into GMO with the desired genelet the scientist know whether the desired gene is successfully inserted into the organism.The antibiotic-resistant gene might pass to pathogensThis has raised concerns that clinical effectiveness of antibiotics will be compromised.The possibility of transferring these genes to recipient cells is considered remote, nevertheless the industry has been advised not to use antibiotics which are frequently used for therapeutic purposes, and to research on the use of alternative marker genes.
13 Some GM food have antibiotic-resistant marker genes… What is the risk?The marker genes may be transferred to other pathogens which become resistant, antibiotics will no longer be effective in treating diseases.This may lead to development of “super pests”
14 Does GM food really benefit farmers and consumers? GM crops are mainly developed by a few large biotechnology companiesThe companies have patents on the GM crops genomeDo the farmers need to pay extra to buy GM seeds?Notes to teachers:Monsanto Co. is the largest GM producer in the worldFor the case of GM rice, some scientists make an effort to have golden rice distributed for free to farmers.Questions:The cost may be higher because the seeds are more expensive
15 Potential risks to the environment? Genes from GM crops might escape, through pollen, to weeds which are relatives of the crops.i.e. the genes may escape into the wild.GM crops may be toxic to some insects that eat them.Dead or dying insects may be eaten by birds.The birds may die because of the toxic effect.This may lead to extinction of some species of insects or birds.Notes to teachers:Laboratory studies show that some butterflies had a lower survival rate when fed on GM plants.
16 Reduction in biodiversity All organisms are interrelated. Changes in one species may have unpredictable consequences in other parts of an ecosystem.GM crops may grow and reproduce faster.They may out-compete other plants in an ecosystem.Reduction in biodiversity
17 Ethical problems? Do we have a right to alter ANY genetic material? Is genetic engineering unnatural?Is genetic engineering ‘playing God’?