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The fossil record of evolution: Data on diversification and extinctionSynoptic studies of the fossil record of complex life on Earth indicate increasingly that extinction, and especially mass extinction, were extremely important driving forces in the history of life. Analysis of a new compilation of geologic ranges for 25,000 genera of marine animals suggests that extinction events were much more frequent in occurrence and variable in magnitude than previously suspected. At least 30 well documented and potential mass extinctions were identified in the dataset. The most recent event, distributed over 260 to 0 ma. exhibit a stationary periodicity of 26.1 + or - 1 ma, implicating a cosmological forcing mechanism. Earlier events, especially in the 575 to 450 ma interval, are more frequent, possibly indicating either a breakdown of periodicity in the more distant past; and as yet undemonstrated diminution of the period length; or frequent aperiodic terrestrial perturbations of a less stable biota superimposed upon the cosmological periodicity.
Document ID
19860017430
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Sepkoski, J. J., Jr.
(Chicago Univ. Chicago, IL, United States)
Date Acquired
August 12, 2013
Publication Date
May 1, 1986
Publication Information
Publication: NASA, Washington Second Symposium on Chemical Evolution and the Origin and Evolution of Life
Subject Category
Space Biology
Accession Number
86N26902
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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