2. 考研
  3. Half a century before Charles Darwin published On the Origin of Species, the French naturalist Jean-Baptiste Lamarck outlined hi

Half a century before Charles Darwin published On the Origin of Species, the French naturalist Jean-Baptiste Lamarck outlined hi

admin2015-02-12  42
问题     Half a century before Charles Darwin published On the Origin of Species, the French naturalist Jean-Baptiste Lamarck outlined his own theory of evolution. A basis of this was the idea that characteristics acquired during an individual’s lifetime can be passed on to their offspring. In its day, Lamarck’s theory was generally ignored or lampooned.
    Now all that is changing. No one is arguing that Lamarck got everything right, but over the past decade it has become increasingly clear that environmental factors, such as diet or stress, can have biological consequences that are transmitted to offspring without a single change to gene sequences taking place. In fact, some biologists are already starting to consider this process as routine. However, fully accepting the idea, provocatively dubbed the "new Lamarckism", would mean a radical rewrite of modern evolutionary theory.
    That’s not all. The implications for public health could also be immense. Some researchers are talking about a paradigm shift in understanding the causes of disease. For example, non-genetic inheritance might help explain the current obesity epidemic, or why there are family patterns for certain cancers and other disorders, but no discernible genetic cause.
    Lamarck’s ideas about exactly how non-genetic inheritance might work were ambiguous at best. He wrote, for example, of the giraffe’s neck becoming elongated over generations because of the animal’s habit of stretching up to feed on leaves in high treetops. The recent research, by contrast, has a firm basis in biological mechanisms—in so-called "epigenetic" change.
    Their studies strongly suggest that a pregnant woman’s diet can affect her child’s epigenetic marks. So perhaps it is not surprising that the effect of certain nutrients is being called into question. And diet is not the only environmental factor that can influence the epigenetic setting of some genes. Michael Meaney at McGill University in Montreal, Canada, and colleagues have found that newborn mice neglected by their mothers are more fearful in adulthood—and that these mice show much higher than normal levels of methylation of certain genes involved in the stress response. In humans, too, there are troubling hints that damaging experiences early in life, while the brain is still developing, can affect epigenetic settings, perhaps with catastrophic consequences.
    In theory, epigenetic marks are wiped clear between generations in mammals. Intriguingly, though, the abnormalities in DNA methylation in scientists’ subjects were not restricted to their frontal cortex: they were also present in their sperm.
By mentioning obesity epidemic, the author intends to______.
选项 A、state the seriousness of this problem
B、prove the influence of Lamarck’s theory on people’s health
C、demonstrate experts still cannot figure out the reason for it
D、explain the genetic cause that lies in it
答案B
解析 属逻辑关系题。题目中的内容出现在第三段第四句，第三段的第二句就是本段的核心观点，因此肥胖的例子也是对此的说明，即L的理论会对公共健康造成很大的影响，故选项B符合题意。选项A属于无中生有，文章并未强调肥胖问题的严重性，故错误。选项C属于答非所问，其表述的内容确实如实，但并非此题的真正意图。选项D属于移花接木，将第三段最后一句中的内容拼凑而成，故错误。
转载请注明原文地址:https://kaotiyun.com/show/mKK4777K
0

考研英语一

相关试题推荐
随机试题
最新回复(0)