从化石记录中可以了解到一些已经灭绝、但已经完全变成海洋生物的鲸目动物。
The fossil record shows that many species have endured for millions of years—so why shouldn we?化石记录显示,已经有许多物种存活了数百万年——那么我们为什么不能呢?
However, for older sequence of evolutionary development, estimates based on parts in the fossil record.然而,对于更古老的进化序列,估测则是基于化石记录的部分。