Without Pikaia we may never have evolved and developed the ability to see how this story unfolded.

如果没有皮卡虫的出现，也许今天的我们就无法用双眼去观察周围的一切。

Pikaia were by no means abundant among the Burgess fossils, so goodness knows how close they may have come to extinction.

Pikaia在布尔吉斯化石中根本不多，因此天知道它们是差多么一点儿走向灭绝。

It's called a Pikaia and it's a little wormlike creature but it's thought that this is a chordate, and that is the branch of life that we're in, so it could that this is our earliest known ancestor.

它叫皮卡虫，确实和普通虫子差不多，不过人们认为它是一种脊索动物，也就是说，它和我们是同一类动物，所以这也许是我们最早的祖先了。

And then there's Herpetogaster, which … I'm not going to describe using my words We even had our own little cousin twitching around in those days -- a little, worm-like swimmer that scientists know as Pikaia.

然后是 Herpetogaster， 它… … 我不想用我的话来描述 那些日子我们甚至有自己的小表弟在抽搐——一种像蠕虫一样的小游泳者，科学家们称之为 Pikaia。