As the world further north dried out, 随着世界北部进一步干旱
As Antarctica became colder and more isolated, 随着南极变得更加寒冷与孤立
But just as their ancestors were beginning to make progress, 但正当它们的祖先开始取得进展时
And it's still just as important today. 这在今天依然非常重要
just as they were 15 million years ago. 与1500万年前别无二致
As it did so, it created a vast shallow sea. 在这个过程中 形成了一片广阔的浅海
just as birds did millions of years ago. 就像数百万年前的鸟类那样