英语听力 学英语,练听力,上听力课堂! 注册 登录
> 在线听力 > 英语高级听力 > 探索世界之生命物语 >  第7篇

探索世界之生命物语 The Human Body: Life Story 7

所属教程:探索世界之生命物语

浏览:

手机版
扫描二维码方便学习和分享
https://online2.tingclass.net/lesson/shi0529/0008/8423/7.mp3
https://image.tingclass.net/statics/js/2012

They haven't changed because their environment has stayed the same. The water they live in bubbles up from deep in the earth, and so it's always the same temperature. But just meters away the environment is very different, away from the thermal vents with the ebb and flow of the water, the temperature fluctuates. Billions of years ago, bacteria were living here too, but as their living conditions changed, they changed as well. From one generation to the next, there were minute alterations. In themselves they were almost insignificant, but these tiny changes started the most amazing process.

--Because if you add up enough tiny changes from generations through millions of generations, you can get a revolutionary transformation.

From being simple bacteria the creatures in these pools became more complicated. Single cells became groups of cells, and groups of cells (became) early plants and animals, and the changes continued. Dozens of species became hundreds, and hundreds turned into tens of thousands. Parts of bodies were adapted to meet new challenges. Great leaps were made. A fish's fins over countless generations developed into legs and it became a reptile. Some reptiles developed feathers and became birds. Others became mammals in every shape and size from blue whale to baboon, every creature we see on the earth today including ourselves. All these happened. It's the miracle of evolution. The human body is just one branch in the huge spreading tree of life that grew from those simple bacteria.

Yet we carry with us the remnants of what has gone before us in our strange past, and there is a place we can go to see just one of those remnants, shaped by one of evolution's truly incredible transformations. It's inside my own head. All we need to do is go and find it.

This is my eardrum, a thin skin stretched tight across my ear canal. But what I want to show you lies on the other side of my eardrum. This device can take me there. I'm inside a huge magnet with a field strong enough to lift a car clean off the ground. It's a magnetic resonant scanner and it can reveal layer by layer what's inside my head. Up to now, this has been the forefront of medical imaging, but we are about to take it one step further.

By putting the medical scans together, we've created a 3-dimensional picture of my own head and I can look at any part of it that I want.

words and expressions

thermal : Of, relating to, using, producing, or caused by heat.
热的:有关、用、产生热的或由热造成的

ebb and flow :潮的涨落,盛衰,消长

minute:Exceptionally small; tiny微小的, 异常小的,极细微的

baboon:狒狒

remnant:A surviving trace or vestige:
遗留下来的痕迹或者残余

eardrum:耳膜

field:magnetic field:磁场

resonant :Producing or exhibiting resonance:
共鸣的,共振的:产生或显示共鸣的
 

用户搜索

疯狂英语 英语语法 新概念英语 走遍美国 四级听力 英语音标 英语入门 发音 美语 四级 新东方 七年级 赖世雄 zero是什么意思大连市澳南苑英语学习交流群

网站推荐

英语翻译英语应急口语8000句听歌学英语英语学习方法

  • 频道推荐
  • |
  • 全站推荐
  • 推荐下载
  • 网站推荐