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，他最钟爱的是一名叫三叶虫的海生物。物一度充满奥陶的海洋，但早已不复存在，除了以化石的形式。

But some also believe that a gamma ray burst was responsible for the Ordovician extinction around 455 million years ago.

但是也有一些科学家认为伽玛射线爆发可能是四十五亿年前奥陶大灭绝的罪魁祸首。

The first one that happens is at the end of the Ordovician period around 400 million years ago.

第一次大灭绝发生在奥陶，大约 4 亿年前。

I have seen grown men glow incandescent with rage over this metaphorical millisecond in life's history, the British paleontologist Richard Fortey has written with regard to a long-running twentieth-century dispute over where the boundary lies between the Cambrian and Ordovician.

我看到大人们为了生命史上一毫秒的问题争得红脖子粗。英国的理查德·福蒂在谈到20世为寒武和奥陶的分界线而展开的旷日持久的辩论时这样写道。

The Ordovician (440 million years ago) and Devonian (365 million) each wiped out about 80 to 85 percent of species.

奥陶（44000万年以前）和泥盆（36500万年以前）分别消灭了大约80%——85%的物。

440 million years ago was the The Ordovician extinction.

4.4亿年前是奥陶灭绝。

For a long time, paleontologists thought the  Silurian was a time of relative stability, with life recovering and flourishing after the mass  extinctions at the end of the Ordovician period.

长以来， 古生物学家认为志留是一个相对稳定的时，在奥陶的大规模灭绝之后， 生命得到了恢复并繁荣发展。

The very first mass extinction we know of is the Late Ordovician extinction that took place 450 million years ago.

我们所知道的第一次大灭绝是发生在 4.5 亿年前的晚奥陶世大灭绝。

Before the Ordovician, terrestrial life was probably limited to microbes.

在奥陶之前，陆地生命 可能仅限于微生物。

This is known as the Great Ordovician Biodiversification Event.

这被称为奥陶生物多样性大 事件。

The fight was finally settled in 1879, with the simple expedient of coming up with a new period, the Ordovician, to be inserted between the two.

这场斗争最终在1879年解决, 简单的权宜之计是提出一个新的时, 奥陶, 被插入两者之间。

Devonian is, of course, from the English county of Devon, Cambrian comes from the Roman name for Wales, while Ordovician and Silurian recall ancient Welsh tribes, the Ordovices and Silurs.

当然, 泥盆来自英国德文郡, 寒武来自威尔士的罗马名称, 而奥陶和志留则让人想起古老的威尔士部落, 奥陶和志留。

Heading into the Ordovician Period, around 485 million years ago, eocrinoids diversified into thousands of forms.

进入奥陶时， 大约4.85亿年前，早海百合分化出了数千形态。

And it might've been pressure to find a new feeding niche that drove this switch from face-up to face-down, since the Ordovician witnessed an explosion in suspension-feeding, with lots of competition for floating bits of food.

可能是因为寻找新的觅食生态位的压力， 导致了从仰面到俯面的转变，因为在奥陶时， 悬浮觅食的生物数量激增，对漂浮的食物颗粒的竞争也变得激烈。

470 million years ago, in the Ordovician Period, the first plants began to live on land.

7亿年前，在奥陶， 第一批植物开始生活在陆地上。

This fish lived in the coastal waters of what's now Bolivia, during the Ordovician Period, some 470 million years ago.

这鱼生活在现在的玻利维亚沿海水域，大约4.7亿年前的奥陶时。

This twofold impact known as the Ordovician-Silurian Extinction, wiped out about 25% of all taxonomic families, including about half of trilobite families.

这次被称为奥陶-志留灭绝事件的双重打击，消灭了大约25%的所有分类科，包括约一半的三叶虫科。

Crinoids became the most abundant echinoderms of the Ordovician, and some were the ancestors of today's stalkless feather stars and stalked sea lilies.

海百合成为了奥陶最丰富的棘皮物，其中一些是今天无茎羽状海百合和有茎海百合的祖先。

The fossils they found were about 488 million years old -- which put them in the Ordovician.

他们发现的化石大约有4.88亿年的历史——这将它们归类到奥陶。

And there are extensive black shale deposits in places like China and northern Africa, dating to the late Ordovician.

在中国和北非等地有大量黑色页岩矿床，可追溯到晚奥陶世。