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.
Så selv før det nedslag blev kendt, selv før forskerne generelt blev enige om en teori om evolution, havde forskere og naturhistorikere i alle lag faktisk delt jordens livshistorie i disse to episoder: Mesozoisk, det midterste liv, og Cenozoisk, det nyere liv.