So even before that impact was known, even before scientists in general came to an agreement over the theory of evolution, scientists and natural historians of all kinds of stripes actually had divided Earth's life's history into these two episodes: Mesozoic, the middle life, and the Cenozoic, the recent life.
所以，在提出慧地大碰撞理论之前， 甚至在大多数科学家承认 进化论之前， 不同领域的科学家和自然学家们 事实上早就把地球的历史 划分为以下两个阶段： 中生代和新生代。