Science. 1982 Mar 19;215(4539):1501-3. doi: 10.1126/science.215.4539.1501.
A new compilation of fossil data on invertebrate and vertebrate families indicates that four mass extinctions in the marine realm are statistically distinct from background extinction levels. These four occurred late in the Ordovician, Permian, Triassic, and Cretaceous periods. A fifth extinction event in the Devonian stands out from the background but is not statistically significant in these data. Background extinction rates appear to have declined since Cambrian time, which is consistent with the prediction that optimization of fitness should increase through evolutionary time.
一项关于无脊椎动物和脊椎动物科的化石数据的新汇编表明，海洋领域的四次大规模灭绝在统计学上与背景灭绝水平明显不同。这四次发生在奥陶纪晚期、二叠纪晚期、三叠纪晚期和白垩纪晚期。泥盆纪的第五次灭绝事件在背景中引人注目，但在这些数据中并不具有统计学意义。自寒武纪以来，背景灭绝率似乎一直在下降，这与随着进化时间适应性应该增加的预测是一致的。
