No fractals in fossil extinction statistics

Statistical analyses of the fossil record seek to discover the mechanisms controlling biotic diversity throughout the Earth's history. Solé et al.1 reported that many extinction time series are statistically self-similar, with 1/f power spectra, suggesting that extinctions are driven by self-organized criticality or by other scale-free internal dynamics of the biosphere. Here we show that the apparent self-similarity and 1/f scaling reported by Solé et al. are artefacts of their interpolation methods. Extinction records that are not interpolated show no evidence of fractal scaling.