Smith A B
Department of Palaeontology, The Natural History Museum, Cromwell Road, London SW7 5BD, UK.
Philos Trans R Soc Lond B Biol Sci. 2001 Mar 29;356(1407):351-67. doi: 10.1098/rstb.2000.0768.
Patterns of origination, extinction and standing diversity through time have been inferred from tallies of taxa preserved in the fossil record. This approach assumes that sampling of the fossil record is effectively uniform over time. Although recent evidence suggests that our sampling of the available rock record has indeed been very thorough and effective, there is also overwhelming evidence that the rock record available for sampling is itself distorted by major systematic biases. Data on rock outcrop area compiled for post-Palaeozoic sediments from Western Europe at stage level are presented. These show a strongly cyclical pattern corresponding to first- and second-order sequence stratigraphical depositional cycles. Standing diversity increases over time and, at the coarsest scale, is decoupled from surface outcrop area. This increasing trend can therefore be considered a real pattern. Changes in standing diversity and origination rates over time-scales measured in tens of millions of years, however, are strongly correlated with surface outcrop area. Extinction peaks conform to a random-walk model, but larger peaks occur at just two positions with respect to second-order stratigraphical sequences, towards the culmination of stacked transgressive system tracts and close to system bases, precisely the positions where taxonomic last occurrences are predicted to cluster under a random distribution model. Many of the taxonomic patterns that have been described from the fossil record conform to a species-area effect. Whether this arises primarily from sampling bias, or from changing surface area of marine shelf seas through time and its effect on biodiversity, remains problematic.
通过对保存在化石记录中的分类单元进行统计，推断出了随时间推移的起源、灭绝和现存多样性模式。这种方法假定化石记录的采样在时间上是有效均匀的。尽管最近的证据表明，我们对现有岩石记录的采样确实非常全面和有效，但也有压倒性的证据表明，可供采样的岩石记录本身因主要的系统偏差而失真。本文展示了按阶段水平为西欧晚古生代沉积物编制的岩石露头面积数据。这些数据显示出一种强烈的周期性模式，与一阶和二阶层序地层沉积旋回相对应。现存多样性随时间增加，在最粗略的尺度上，与地表露头面积脱钩。因此，这种增加趋势可被视为一种真实模式。然而，在以数千万年为单位衡量的时间尺度上，现存多样性和起源速率的变化与地表露头面积密切相关。灭绝峰值符合随机游走模型，但较大的峰值仅出现在相对于二阶地层序列的两个位置，即叠置海侵体系域的顶点附近和靠近体系基底的位置，而这正是根据随机分布模型预测分类单元最后出现会聚集的位置。从化石记录中描述的许多分类模式都符合物种 - 面积效应。这主要是由采样偏差引起的，还是由于海洋陆架海的表面积随时间变化及其对生物多样性的影响，仍然存在问题。
