Up from the Depths

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Science  05 Aug 2011:
Vol. 333, Issue 6043, pp. 675
DOI: 10.1126/science.333.6043.675-b

More than 90% of species are thought to have become extinct at the end of the Permian (245 million years ago). It was initially thought that ecosystems took millions of years to recover, and that both diversity and origination rates were suppressed for most groups, but a variety of recent work is beginning to show a more rapid and complex pattern of recovery. Song et al. examined marine microfossils after the extinction from seven sections in China, particularly focusing on ocean floor environments. Their data show that recovery of deep ocean environments was delayed only about 1 million years. Interestingly, rapid recovery seems to have begun in offshore areas first, and progressed to shallower and coastal environments, in contrast to the situation seen for open-ocean species. Other studies have shown rapid recovery of some organisms (ammonoids, for example), soon after the extinction, whereas coral reef environments seem to reappear much later after about 5 million years. The authors thus suggest that recovery may reflect intrinsic evolutionary rates in surviving taxa, along with the effects of minor selective extinctions.

Geology 39, 739 (2011).

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