用户名: 密码: 验证码:    注册 | 忘记密码?
首页|听力资源|每日听力|网络电台|在线词典|听力论坛|下载频道|部落家园|在线背单词|双语阅读|在线听写|普特网校
您的位置:主页 > 听力训练资源 > 听力文摘 >

【听力文摘】南极森林

2014-06-27    来源:普特英语听力    【      美国外教 在线口语培训
— 查看译文 —

tips:怎样阅读才是有质量的阅读了? 中英对照请点击【中英对照】查看译文请点击 【查看译文】进行核对。


Antarctic Forests

"Dear A Moment of Science, I know that around 250 million years ago the Earth was a lot hotter than it is today. So I’m wondering what that meant, exactly? How did the planet look different than it does today?"

Well, the Earth was different in lots of ways hundreds of millions of years ago. One major difference linked to warmer global temperatures was that Antarctica was not the icy, barren wasteland it is today. In fact, it was covered by forest.

What kind of forest? That’s what scientists are trying to figure out. Fossilized leaf impressions seem to show that mats of leaves once covered the ground. That suggests that the trees were deciduous, meaning that they shed their leaves at the same time. But fossilized wood from the region tells a different story.

Cells in the tree rings show a pattern of growth that’s consistent with evergreen trees, meaning trees that don’t shed their leaves. So the ancient Antarctic forests were probably a mix of evergreen and deciduous trees. Analysis of carbon molecules in the fossil woods shows something similar. And it also suggests that the forests have some similarities to tropical forests today.


Another question is how Antarctic forests dealt with constant daylight half the year and near total darkness the other half. Wouldn’t that mess with their ability to photosynthesize? More research might reveal the answer.

南极森林

亲爱的科学一刻,我知道大约在2.5亿年前,地球要比今天热的多的多。所以,我就在想这到底意味着什么?那时的地球相比今天而言有多大的不同呢?

几亿年前的地球与今天相比在很多方面都有所不同。最主要的一个差异与全球温度有关,那就是南极当时并不像今天这样是一片被冰雪覆盖的荒芜之地。事实上,当时的南极是一片森林。

什么样的森林呢?科学家们也在试图寻找答案。从树叶化石的痕迹来看,当时的地表被层层的树叶所覆盖,这说明树木会在每年的相同时间内落叶。但是该地区的木化石却又说明了另一种情况。

年轮的细胞体现出树木的生长方式与常青树相同。也就是说它们不会落叶。因此,古代的南极森林可能是一片常青树和落叶树的杂交林。对木化石中碳分子的分析结果也显示有所相似之处。同时,分析结果还表明了南极森林和今天的热带雨林也存在一定的相似。

另一个问题就是南极森林是如何适应极昼和极夜现象的。这难道不会扰乱它们光合作用的能力吗?想要找出答案可能还需要进行更多的研究。

【本译文由普特网友 kevinde  提供】



下载本文pdf文件
顶一下
(43)
84.3%
踩一下
(8)
15.7%
手机上普特 m.putclub.com 手机上普特
[责任编辑:Tina]
------分隔线----------------------------
发表评论 查看所有评论
请自觉遵守互联网政策法规,严禁发布色情、暴力、反动的言论。
评价:
表情:
用户名: 密码: 验证码:
  • 推荐文章
  • 资料下载
  • 讲座录音
普特英语手机网站
用手机浏览器输入m.putclub.com进入普特手机网站学习
查看更多手机学习APP>>