Shelly creatures such as trilobites and brachiopods, of whose ancestors there is little sign in the rocks, are suddenly everywhere.

像三叶虫、腕足动壳类动的祖先没有在岩层中留下什么痕迹，但它们的遗迹却突然间比比皆是。

One hundred million years later, the warm, shallow seas were packed with tiny plants and animals — essentially, hors d'oeuvres for a plethora of bigger creatures like trilobites, conodonts, brachiopods, and corals.

一千年之后，温暖的浅海充满了微小的植和动——基本上是大量大型生的开胃菜，如同三叶虫，牙形虫，腕足类和珊瑚。

It seems like a big number, he agreed, but you have to remember that millions upon millions of trilobites lived for millions upon millions of years in ancient seas, so twenty thousand isn't a huge number.

“看来真是不少，”他表示同意，“不过，你要记住，成亿只三时虫在古代的海洋里生活了成亿年，因2个数字不算多。

A single-file line of traveling trilobites, all facing the same direction, were caught in a sediment avalanche 480 million years ago.

科学家在4.8亿年前发生的沉淀雪崩中，发现了一排面朝同一方向迁徙的三叶虫。

From about five hundred million years ago, big creatures became much more common, from trilobites to trees to tyrannosaurus rex.

从大约五亿年前开始，大型生变得更加常见，从三叶虫到树木再到雷克斯霸王龙。

Trilobite diversity dwindled, and come about 360 million years ago, only one of the 10 former trilobite orders remained.

三叶虫的多样性减少，到了三亿六千年前，过去所有的三叶虫目中，只有十目存活下来。

It's Earth about 500 million years ago, when these creatures, called trilobites, prospered.

是大约五亿年前的地球，种生叫做三叶虫，当时地球是它们的天下。

But his first love is a type of marine creature called trilobites that once teemed in Ordovician seas but haven't existed for a long time except in fossilized form.

但是，他最钟爱的是一种名叫三叶虫的海生动。那种动一度充满奥陶纪的海洋，但早已不复存在，除了以化石的形式。

At 9: 04 P.M. trilobites swim onto the scene, followed more or less immediately by the shapely creatures of the Burgess Shale.

晚上9点4分，三叶虫登场了，几乎紧接着出场的是布尔吉斯页岩那些形状美观的动。

We've found trilobite fossils on every single continent — many in unlikely environments that were once part of the ocean floor.

我们在每一个大陆上都发现了三叶虫化石——许多发现地都曾经是海底，原以为是不太可能有三叶虫踪影的地方。

Finding a complete trilobite fossil is still a big moment for a paleontologist.

发现一块完整的三叶虫化石对古生学家来说，仍是一件大事。”

Like modern arthropods, trilobites had compound eyes composed of many tiny lenses.

就像现代的节肢动，三叶虫也有由许多小晶体组成的复眼。

For almost all of Earth's history before the rise of the trilobites, life had mostly consisted of microscopic marine organisms.

根据地球的历史，在三叶虫兴起之前，生命几乎都是海洋里的显微有机体。

Trilobites have no direct descendants, but their evolutionary cousins are alive and well.

三叶虫没有直系的后代，但它们在演化上的表亲现在仍然活得很好。

With so much time at their disposal, the trilobites proliferated prodigiously.

三叶虫有那么漫长的支配时间，因数量激剧增加。

Even more awkwardly anomalous was another species of trilobite found in Europe and the Pacific Northwest but nowhere in between, which would have required not so much a land bridge as a flyover.

另一种三叶虫的情况更是反常，它出现在欧洲和美国西北部的太平洋沿岸，而中间地带却不见踪影。与其说需要一座陆桥，不如说需要一座立交桥。

And, as the earliest known animals with complex eyes, trilobites had a unique perspective on the ancient world.

三叶虫也是目前所知最早具有复眼的动，它们对古老的世界有着独特的视角。

Some creatures like trilobites and brachiopods survived though.

不过，一些生如三叶虫和腕足动幸存下来。

But, trilobites took the benefits of physical complexity much further.

但是，三叶虫将身体结构复杂性的优势发挥得更进一步。

It was one of the early crustaceans called Trilobites.

它是一种叫做三叶虫的早期甲壳类动。