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  32
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.
The basic content of Lamarck’s theory lies in______.
选项 A、descendants’ inheritance of certain traits
B、overthrowing the evolutionary theory of Darwin
C、environment’s biological consequences
D、the change of gene sequences
答案A
解析 属事实细节题。题目意为“L的理论的基础在于…”，可知其为文章第一段第二句的改写，该句中提到基础就是个体的一些习性可以传递给后代。选项A意为“后代对于前人特点的遗传”，故符合题意。选项B属于无中生有，文章中提到L的理论是在达尔文的进化论之前提I叶J的，故错误。选项C和D均属于移花接木，都来自第二段的部分内容，不合题意，故均错误。
转载请注明原文地址:https://kaotiyun.com/show/GKK4777K
0

考研英语一

相关试题推荐
随机试题
最新回复(0)