Colloquium paper: dynamics of origination and extinction in the marine fossil record

Abstract

The discipline-wide effort to database the fossil record at the occurrence level has made it possible to estimate marine invertebrate extinction and origination rates with much greater accuracy. The new data show that two biotic mechanisms have hastened recoveries from mass extinctions and confined diversity to a relatively narrow range over the past 500 million years (Myr). First, a drop in diversity of any size correlates with low extinction rates immediately afterward, so much so that extinction would almost come to a halt if diversity dropped by 90%. Second, very high extinction rates are followed by equally high origination rates. The two relationships predict that the rebound from the current mass extinction will take at least 10 Myr, and perhaps 40 Myr if it rivals the Permo-Triassic catastrophe. Regardless, any large event will result in a dramatic ecological and taxonomic restructuring of the biosphere. The data also confirm that extinction and origination rates both declined through the Phanerozoic and that several extinctions in addition to the Permo-Triassic event were particularly severe. However, the trend may be driven by taxonomic biases and the rates vary in accord with a simple log normal distribution, so there is no sharp distinction between background and mass extinctions. Furthermore, the lack of any significant autocorrelation in the data is inconsistent with macroevolutionary theories of periodicity or self-organized criticality.

Fig. 1.

Per-interval instantaneous origination rates (A) and extinction rates (B) of marine invertebrate genera over the Phanerozoic. Data are binned into 48 intervals averaging 11.0 Myr in duration.

Fig. 2.

Origination rates (blue lines) and extinction rates (red lines) after being detrended by using exponential functions.

Fig. 3.

Key relationships between variables that govern marine invertebrate diversity dynamics on the Phanerozoic scale. Paleozoic points (black diamonds) and Meso-Cenozoic points (gray circles) show the same patterns in each case, and the values including the Permo-Triassic mass extinction (triangle) are consistent with the trends. (A) Correlation between diversity in one interval and extinction rates in the next interval. (B) Correlation between extinction rates in one interval and origination rates in the next.

Fig. 4.

Predicted recoveries from mass extinctions modeled on the global Permo-Triassic and Cretaceous-Tertiary events (81% and 53% losses, respectively) and the early Pleistocene extinction in the Caribbean (32% loss) (67).