无忧雅思网_雅思预测_雅思机经_雅思考试_雅思资料下载_雅思名师_2018年雅思考试时间

雅思写作素材:Cloning

都是由英文为母语人士写成,对于雅思写作很有参考价值,对于背景介绍和经典句型,用法等来说都是不可多得的好素材!!!


Cloning

Shortly after the announcement that British scientists had successfully cloned a sheep, Dolly, cloning humans has recently become a possibility that seems much more feasible in today's society. The word clone has been applied to cells as well as to organisms, so that a group of cells stemming from a single cell is also called a clone. Usually the members of a clone are identical in their inherited characteristics that is, in their genes except for any differences caused by mutation. Identical twins, for example, who originate by the division of a single fertilized egg, are members of a clone; whereas nonidentical twins, who derive from two separate fertilized eggs, are not clones. (Microsoft?Encarta?97 Encyclopedia). There are two known ways that we can clone humans. The first way involves splitting an embryo into several halves and creating many new individuals from that embryo. The second method of cloning a human involves taking cells from an already existing human being and cloning them, in turn creating other individuals that are identical to that particular person. With these two methods at our desposal, we must ask ourselves two very important questions: Should we do this, and Can we? There is no doubt that many problems involving the technological and ethical sides of this issue will arise and will be virtually impossible to avoid, but the overall idea of cloning humans is one that we should accept as a possible reality for the future. Cloning humans is an idea that has always been thought of as something that could be found in science fiction novels, but never as a concept that society could actually experience. Today's technological speed has brought us to the piont to where almost anything is possible. Sarah B. Tegen, '97 MIT Biology Undergraduate President states, I think the cloning of an entire mammal has shown me exactly how fast biology is moving ahead, I had no idea we were so close to this kind of accomplishment. Based on the current science , though, most of these dreams and fears are premature, say some MIT biologists. Many biologist claim that true human cloning is something still far in the future. This raises ethical questions now as towhether or not human cloning should even be attempted.

There are many problems with cloning humans. One method of human cloning is splitting embryos. The main issue as to whether or not human cloning is possible through the splitting of embryos began in 1993 when experimentation was done at George Washington University Medical Center in Washington D.C. There Dr. Jerry Hall experimented with the possibility of human cloning and began this moral and ethical debate. There it was concluded that cloning is not something that can be done as of now, but it is quite a possibility for the future. These scientists experimented eagerly in aims of learning how to clone humans. Ruth Macklin of U.S. News & World Report writes, Hall and other scientists split single humans embryos into identical copies, a technology that opens a Pandora's box of ethical questions and has sparked a storm of controversy around the world