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Breathing room for early animals

Fischer, Woodward W. (2016) Breathing room for early animals. Proceedings of the National Academy of Sciences of the United States of America, 113 (7). pp. 1686-1688. ISSN 0027-8424. PMCID PMC4763752. doi:10.1073/pnas.1525100113.

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If life has been present on our planet for much of its history—more than three and a half billion years—why did it take so long for animals to appear? This question emerged long ago from the incipient fabric of the fossil record, which embodies the sudden appearance of metazoans in sedimentary strata deposited near the end of Precambrian time—and scientists have wrestled with this issue now for well over a hundred years (1). For the past 50 or so years, the most popular and pertinacious hypotheses have concerned atmospheric dioxygen (2–5). Because of their aerobic physiology, the idea was that O_2 levels were perhaps too low to have supported animals until sometime near the end of Precambrian time, and that rising O2 levels thereafter provided a quantum evolutionary leap of sorts for aerobic biology culminating in the “late” evolution of animals (3). A recent study of middle Proterozoic sedimentary rocks in China, however, favors a different view—suggesting that O_2 levels capable of supporting animal physiology were present more than 500 million years before the appearance of animals (6).

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Fischer, Woodward W.0000-0002-8836-3054
Additional Information:© 2016 National Academy of Sciences. Published online before print February 3, 2016. Author contributions: W.W.F. wrote the paper. The author declares no conflict of interest. See companion article 10.1073/pnas.1523449113.
Issue or Number:7
PubMed Central ID:PMC4763752
Record Number:CaltechAUTHORS:20160204-080952661
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Official Citation:Woodward W. Fischer Breathing room for early animals PNAS 2016 113 (7) 1686-1688; published ahead of print February 3, 2016, doi:10.1073/pnas.1525100113
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:64220
Deposited By: Tony Diaz
Deposited On:04 Feb 2016 17:23
Last Modified:10 Nov 2021 23:27

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