1、话题阅读新课导入课后限时训练【文章导语】Researchers have found a link between the heating up ofthe Earth and the size of mammals.For example,as temperatures went up,thesize of horses went down,and vice versa.“Global warming could make humans shorter，”warn researcherswho claim to have found evidence that it caused the w
2、orlds first horses toshrink nearly 50 million years ago.In fact,a team from the universities ofFlorida and Nebraska says it has found a linkbetween the heating up of the Earth and thesize of mammalshorses,in this case.Researchers used fossils to follow the evolution of horses from theirearliest appe
3、arance 56 million years ago.“As temperatures went up their sizewent down,and vice versa;at one point they were as small as a house cat，”said Dr Jonathan Bloch,curator of the Florida Museum of Natural History.The researchers say that the current warming could have the same effecton mammalsand could e
4、ven make humans smaller.Horses started out small,about the size of a small dog like a miniatureschnauzer.Whats surprising is that after they first appeared,they thenbecame even smaller and then dramatically increased in size,and that exactlycorresponds to the global warming event,followed by cooling
5、.“It had been known that mammals were small during that time and that it was warm,but we hadnt understood that temperature specifically was driving the evolution of body size，”Dr Bloch said in the Science journal.译文研究人员警告：“全球变暖会让人类变矮。”他们声称已经找到全球变暖引起5千万年前最早出现的马变小的证据。事实上，一个来自佛罗里达州和内布拉斯加州的大学的团队声称他们已经找到
6、了全球变暖和哺乳动物体型大小之间的联系这一案例中的哺乳动物就是指的马。研究人员利用化石追溯马从5 600万年前诞生至今的进化历程。“随着温度的升高，它们的个头变小，反之则变大；它们曾一度像家猫一样大。”来自佛罗里达州的自然历史博物馆馆长乔纳森布洛赫博士这样说道。研究人员称，目前的变暖也许会对哺乳动物产生相同的影响甚至会让人类的身高也变矮。马最初的个头很小，和小狗的个头差不多，与迷你雪纳瑞犬不相上下。让人惊讶的是，最初马诞生一段时间之后，它们的个子甚至变得更小，之后又显著地变大，而这些变化和全球变暖以及之后的变冷正好是一致的。布洛赫博士在科学杂志上发文说：“众所周知，哺乳动物在当时个头比较小，而
7、且那时候气温较暖和，但我们还没意识到正是气温驱使着身体大小的变化。”词海拾贝1mammal n哺乳动物2shrink v变小，减少，收缩3fossil n化石4evolution n进化，演进5current adj.现在的，目前的 n(水、气、电)流6dramatically adv.戏剧地，引人注目地，显著地佳句欣赏“Global warming could make humans shorter，”warn researcherswho claim to have found evidence that it caused the worlds first horses toshrink nearly 50 million years ago.研究人员警告：“全球变暖会让人类变矮。”他们声称已经找到全球变暖引起5千万年前最早出现的马变小的证据。课后 限时训练
