Data from: Two-phase increase in the maximum size of life over 3.5 billion years reflects biological innovation and environmental opportunity

NOTE: See also http://bodysize.nescent.org. ABSTRACT: The maximum size of organisms has increased enormously since the initial appearance of life >3.5 billion years ago (Gya), but the pattern and timing of this size increase is poorly known. Consequently, controls underlying the size spectrum of the global biota have been difficult to evaluate. Our period-level compilation of the largest known fossil organisms demonstrates that maximum size increased by 16 orders of magnitude since life first appeared in the fossil record. The great majority of the increase is accounted for by 2 discrete steps of approximately equal magnitude: the first in the middle of the Paleoproterozoic Era (≈1.9 Gya) and the second during the late Neoproterozoic and early Paleozoic eras (0.6–0.45 Gya). Each size step required a major innovation in organismal complexity—first the eukaryotic cell and later eukaryotic multicellularity. These size steps coincide with, or slightly postdate, increases in the concentration of atmospheric oxygen, suggesting latent evolutionary potential was realized soon after environmental limitations were removed.

注意：另可参阅 http://bodysize.nescent.org。
摘要：自超过35亿年前（Gya，十亿年前）生命首次出现以来，生物的最大体型已出现了极为显著的增长，但该增长的模式与时间节点仍尚未得到充分认知。因此，全球生物群体型谱背后的调控机制难以被准确评估。我们基于时期尺度汇编的已知最大化石生物数据集显示，自化石记录中生命首次出现以来，生物最大体型已提升了16个数量级。该增长的绝大多数部分由两个规模大致相当的离散跃迁构成：第一次发生在古元古代（Paleoproterozoic Era）中期（约19亿年前），第二次则出现在新元古代（Neoproterozoic）晚期至古生代（Paleozoic）早期（6亿至4.5亿年前）。每一次体型跃迁都伴随着生物复杂度的重大革新——先是真核细胞（eukaryotic cell）的起源，随后是真核多细胞性（eukaryotic multicellularity）的演化。这些体型跃迁与大气氧浓度的上升相吻合，或略晚于氧浓度的上升阶段，这表明环境限制解除后，潜在的演化潜能很快便得以实现。