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Increase in the cumulative number of clades with increasing age in a sample assembled according to other criteria by McPeek and Brown (110) and McPeek (3). Estimated rates of extinction were arthropods, 0.070 ± 0.003; birds, 0.093 ± 0.010; fish, 0.105 ± 0.021; mammals, 0.062 ± 0.014; flowering plants (Magnoliaphyta), 0.040 ± 0.009.
