Data from: Tempo does not correlate with mode in the fossil record

The dominating view of evolution based on the fossil record is that established species remain more or less unaltered during their existence. Substantial evolution is on the other hand routinely reported for contemporary populations, and most quantitative traits show high potential for evolution. These contrasting observations on long and short time scales are often referred to as the paradox of stasis, which rests on the fundamental assumption that periods of morphological stasis in the fossil record represent minimal evolutionary change. Investigating 450 fossil time series, I demonstrate that the non-accumulating morphological fluctuations during stasis travel similar distances in morphospace space compared to lineages showing directional change. Hence, lineages showing stasis are commonly undergoing considerable amounts of evolution, but this evolution does not accumulate to produce large net evolutionary changes over time. Rates of evolutionary change across modes in the fossil record may be more homogenous than previously assumed and advocated, supporting the claim that substantial evolution is not exclusively or causally linked to the process of speciation. Instead of exemplifying minimal evolution, stasis likely represents information on the dynamics of the adaptive landscape on macroevolutionary time scales, including the persistence of adaptive zones and ecological niches over millions of years.基于化石记录的主流演化观认为，已确立的物种种群在存续期间基本保持不变。然而，现生种群中常被报道存在显著的演化现象，且大多数数量性状均具备较高的演化潜力。这种在长、短时间尺度上观测到的矛盾现象通常被称为停滞悖论（stasis paradox），其核心前提假设为：化石记录中出现的形态停滞时期代表了极微小的演化变化。通过对450条化石时间序列的研究，本文证明：停滞阶段中未发生累积的形态波动，在形态空间中移动的距离与表现出定向演化的演化支相当。因此，表现出停滞的演化支通常正在经历显著的演化过程，但这类演化并未发生累积，无法在长时间尺度上产生较大的净演化变化。化石记录中不同演化模式下的演化变化速率，或许比此前的假设和研究主张的更为同质化，这支持了“显著演化并非仅与物种形成过程存在排他性或因果关联”这一论断。停滞现象并非代表极缓慢的演化，反而可能为我们提供宏演化时间尺度下适应景观的动态信息，包括适应区与生态位在数百万年间的存续情况。