【最新版】2014届高考英语一轮单元复习精品阅读理解提升文章精选一百篇 (74)

　　Unit 75 The Concerns about Genetically Modified Food Genetic Modification (GM) has the power to save lives through its use in medicine, such as the production of insulin for diabetics or the treatment of genetic disorders. The current outcry comes when it is used to produce food. Some of these public concerns reflect real problems, but others are fuelled by misinformation and over-dramatization. There is nothing new about crop modification; plant breeders have been doing this since agriculture began. The wonderful range of apples or potatoes we now enjoy is the result of crossing different varieties. Cabbages, Brussels sprouts, cauliflower, kohlrabi and broccoli all originated from one botanical species. Modern molecule biology has enabled us to go much further. We can now isolate the gene from a particular characteristic of an organism and transfer it to another species. It is this practice of transforming a plant with alien genes -- perhaps from an animal or bacterium --that is causing all the controversy. There are four main concerns. Scientists can now take a gene for resistance to particular herbicide and transplant it to a crop: when these plants are sprayed with weedkiller, the weeds were destroyed while the crop is unharmed. A prime concern is the harmful effect this could have on the biodiversity of farmland, where so many insects, birds and other animals depend on "weed" species. Another fear is that alien genes from a GM plant could escape into a wild population of a related species. Since plants are fertilized by pollen carried through air, often for long distances, this is entirely possible. A wild species modified in this way with pesticide resistance could become a superweed, while a species that became unnaturally resistant to animals could disrupt the food chain. The third worry concerns a proposal to produce seeds for cereals that cannot produce next year's seeds. This "terminator technology" would benefit seed companies, since farms would be forced to buy new seeds annually. But the same technology could be devastating to some farmers in the developing countries who depend on saving seeds for next year's crop. Fortunately this technology is not yet in use and there has been strong pressure to abandon it. It is unlikely that the current modifications are harmful to health. However the introduction of animal genes into plants presents considerable ethical difficulties to vegetarians and members of religions that forbid the eating of certain animals. This is why people are demanding all GM food products be labeled. The public has a right to know what they are eating -- and a right to choose. In America GM is well regulated, but this cannot be said for some other nations. One problem is that this technology is commercially motivated. Because companies developing GM food want to introduce it as quickly as possible, it is being rushed without adequate research or precautions. GM is here to stay, and there is no doubt it will save lives. But like so many other scientific discoveries -- such as splitting the atom -- it can be seriously misused. Instead of condemning the techniques, we should ensure it is used wisely. We need to evaluate each application carefully, from environmental and ethical standpoints, and we must urge governments and companies to use GM for good rather than for greed.