Which group of amniotes do you think dinosaurs belong to?

你认为恐龙属于哪一组羊膜动物？

These arid wastelands would’ve been uninhabitable for early tetrapods, but not for the amniotes.

这些干旱荒地 对于早期四足动物来说是不适宜居住，但对于羊膜动物来说却不是。

So the initial 30% of the history of the amniote egg unfolded without leaving a trace.

因此，羊膜卵最初 30% 历史展开得无影无。

Amniotes with one temporal fenestrae are called synapsids.

具有一个颞孔羊膜动物称为突触。

And amniotes with two temporal fenestrae are called diapsids.

具有个颞孔羊膜动物被称为双孔动物。

Because, eggs, especially soft-shelled, leathery eggs like we'd expect to see in early amniotes, don't fossilize well.

因为，蛋，尤其是我们期望在早期羊膜动物中软壳革质蛋，不能很好地变成化石。

Amniotes can be subdivided into several groups based on the number of holes or fenestra in the skull.

羊膜动物可以根据头骨上孔或孔数量细分为几个组。

Now, reptiles are amniotes, and so are mammals.

现在，爬行动物是羊膜动物，哺乳动物也是。

But the amniotes, being better adapted to drier conditions, expanded into a variety of new niches, and dominated the land.

但是羊膜动物更好地适应了干燥环境，扩展各种新生态位，并主宰了土地。

But on an increasingly dry planet, that gave amniotes a critical advantage.

但在一个日益干燥星球上，这给了羊膜动物一个关键优势。

The evolution of the shelled egg was a milestone in animal evolution, helping those first amniotes take over the land.

带壳蛋进化是动物进化一个里程碑，帮助第一批羊膜动物占领了土地。

Some of our earliest fossil records of amniote eggs are from dinosaurs like Mussaurus patagonicus, which lived around 215 million years in Argentina.

我们最早一些羊膜卵化石记录来自恐龙， 例如巴塔哥尼鼠龙，它们在根廷生活了大约 2.15 亿年。

As the Permian progressed, amniote predators like Dimetrodon, Ophiacodon, and eventually saber-toothed gorgonopsians became widespread.

随着二叠纪进展，羊膜动物捕食者如异齿龙、蛇夫和最终剑齿蛇目动物变得普遍。

They saved those animals known as amniotes from extinction and may have set the stage for their invasion of dry land.

他们拯救了那些被称为羊膜动物动物免于灭绝，并可能为它们入侵旱地奠定了基础。

By the time this catastrophe occurred, most lineages of temnospondyls had already gone extinct, under pressure from the amniotes.

这场灾难发生时，在羊膜动物压力下，大多数突椎动物谱系已经灭绝。

But all that changed after aquatic amniotes started to spread.

但在水生羊膜动物开始传播后，一切都变了。

Some reptiles continued laying eggs like those of early amniotes, which were soft and leathery, like turtles still do today.

一些爬行动物继续像早期羊膜动物那样产卵，这些卵柔软而坚韧， 就像今天海龟一样。

So by digging into the genomes of these living amniotes, we can start to tell the story of how and when the egg came first.

因此， 通过深入研究这些活羊膜动物基因组，我们可以开始讲述卵是如何以及何时首先出现故事。

During the Triassic as dinosaurs were evolving to fill large bodied ecological niches on land the other amniote groups were evolving to fill the sea and the air.

在三叠纪期间，随着恐龙进化以填充陆地上大型生态位，其他羊膜动物群也在进化以填充海洋和空气。

Amniotes first appeared nearly 315 million years ago, in the Carboniferous Period.

羊膜动物首次出现在大约 3.15 亿年前石炭纪时期。