听力文本

Oh it's completely new. By the time you get to the end of the Devonian for the very first time in Earth history
噢，它是全新的。到了泥盆纪末期，地球历史上首次出现
animals and plants are living on land in a significant, permanent way.
动植物以一种重要而永恒的方式在陆地上生活
That's, that's brand new and a lot of open niches in that waiting to be exploited.
这都是全新的，许多开放的小生境正等着它们去开发
Those new niches were the margins of this watery world.
这些新的生境正是整个水世界的边缘
In the tangle of vegetation limbs with fingers would have given tetrapods a unique advantage over fish.
在缠结交错的植被中，拥有长趾头的四肢将使四足动物比鱼更具备独特的优势

I think we have to think of these fins or, or limbs, or flims as
我想我们应该都认同这些鳍，或者说是肢或腿
something that would be used by the animal for moving through more complex environments like swamps,
很可能是被用来在沼泽之类的复杂环境中穿梭移动
or environments that, where there may have been trees down in channels,
或是在树枝掉落进水道的环境中，以及浅水中
or just shallow water to pursue prey or to escape the guy who's trying to prey upon you.
搜捕猎物和躲避想要吃掉它的天敌
And there was most definitely something from which to escape.
而且那时的确有需要避让的东西
Over and over again Daeschler and his team found evidence of a fish called hyneria, a predator of terrifying proportions.
Daeschler和他的小组一次又一次地发现一种叫做含肺鱼的化石证据，它是一种体型巨大的恐怖掠食者
Hyneria is the most common, lobe-finned fish at this site. It's also the biggest.
含肺鱼是整个地方最常见的肉鳍鱼，它也是最大的
It's probably two or three metres long.
它可能有2--3米长
This, this is a single tooth from a large hyneria and these were carnivorous obviously.
这是含肺鱼的一颗牙齿，可见它是食肉动物

词汇解析

1.the margin of ……的边缘
I traced a huge star and three exclamation points in the margin of my notebook as he moved onto another subject.
当他换下个话题时，我在笔记本边上特意做了一个大星号和三个感叹号。

2.prey upon 掠夺，折磨；捕食
Baboons most often form close bonds with relatives, the researchers said, and the stability of those connections is partly a matter of luck since lions and leopards often prey upon baboons.
研究者表示，狒狒通常会与亲属建立亲密的关系，不过由于狮子和豹子的捕食，使得这种关系的稳定性含有一定的运气成分。

视频及简介

19世纪，英国生物学家赫胥黎在研究了尼安德特人的头骨以后，认为是一个具有猿脸的头骨，但决不是人与猿之间的中间缺环。这就告诉我们，人与猿之间的亲缘关系，似乎还应该有一环。1891年发现直立猿人（爪哇猿人）的骨胳，证明这个缺环确实是存在的。可是，日本的人类学家认为爪哇猿人尚不是真正的中间缺环。那么，在猿与人之间到底应该是什么样的一环呢？在埃塞俄比亚发现的早期人科动物化石，很可能是过渡物种。这一发现，弥补了原始人类进化中的一个“缺环”。