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
原声例句
宇宙的奇迹
万物简史
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。
宇宙的奇迹
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。
PBS地球-动物趣闻
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。
中文百科
皮卡虫
皮卡虫（学名Pikaia），又名皮凯亚虫或皮克鱼，是寒武纪的一类已灭绝动物，其化石在加拿大不列颠哥伦比亚的伯吉斯页岩发现。它是由查尔斯·沃尔科特（Charles Walcott）发现及于1911年描述。由于皮卡虫化石上有明显及规则的节，沃尔科特将牠分类在多毛纲中。牠的样子很像头索纲，游泳时可能更像鳗鱼。
于1979年再次审查柏吉斯页岩的动物群时，古生物学家康卫·毛里斯（Simon Conway Morris）因皮卡虫有非常原始的原脊索，故将牠分类在脊索动物门中，使牠可能成为现今脊椎动物的最早祖先。但昆明鱼与海口鱼的考古年代又比皮卡虫更早。
英语百科
Pikaia 皮卡虫
Pikaia gracilens is an extinct genus of chordate animal known from the Middle Cambrian Burgess Shale of British Columbia. Sixteen specimens are known from the Greater Phyllopod bed, where they comprised 0.03% of the community. It resembles the lancelet and perhaps swam much like an eel.