2. 职称英语
  3. The balance of nature is a very elaborate and very delicate system of checks

The balance of nature is a very elaborate and very delicate system of checks

游客2023-12-09  37
问题     The balance of nature is a very elaborate and very delicate system of checks and counterchecks. It is continually being altered as climates change, as new organisms evolve, as animals or plants permeate to new areas. But the alterations have in the past, for the most part, been slow, whereas with the arrival of civilized man, their speed has been multiplied manifold: from the evolutionary time-scale, where change is measured by periods of ten or a hundred thousand years, they have been transferred to the human time-scale in which centuries and even decades count.
    Everywhere man is altering the balance of nature. He is facilitating the spread of plants and animals into new regions, sometimes deliberately, sometimes unconsciously. He is covering huge areas with new kinds of plants, or with houses, factories, slag-heaps and other products of his civilization. He exterminates some species on a large scale, but favors the multiplication of others. In brief, he has done more in five thousand years to alter the biological aspect of the planet than has nature in five million.
选项
答案     自然界的平衡是一个抑制与反抑制的体系，复杂且精细。这种平衡无时无刻地随着气候的变化、新物种的进化以及动植物向新领域的渗透而变化。但是这种变化在以前，大体上是比较缓慢的，只是随着人类文明的到来，这种变化才大大加速：原来的变化速度是以进化时间表——几万乃至几十万年为计量单位的，现在的变化速度则按人类的时间表——几个世纪乃至几十年为单位。
    人类在到处改变着自然界的平衡。人们正有意无意地促使动植物加速向新地域扩展。大片的土地被人类用各种新植物、楼房、工厂、矿渣或其他人类文明的产物覆盖。一些物种被大规模灭绝，另一些又被加速繁衍。简而言之，人类五千年使地球生物圈发生的变化远远大于大自然自身五百万年发生的变化。
解析
转载请注明原文地址:https://www.tihaiku.com/zcyy/3256879.html
相关试题推荐
随机试题
最新回复(0)