NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Periodicity in extinction and the problem of catastrophism in the history of lifeThe hypothesis that extinction events have recurred periodically over the last quarter billion years is greatly strengthened by new data on the stratigraphic ranges of marine animal genera. In the interval from the Permian to Recent, these data encompass some 13,000 generic extinctions, providing a more sensitive indicator of species-level extinctions than previously used familial data. Extinction time series computed from the generic data display nine strong peaks that are nearly uniformly spaced at 26 Ma intervals over the last 270 Ma. Most of these peaks correspond to extinction events recognized in more detailed, if limited, biostratigraphic studies. These new data weaken or negate most arguments against periodicity, which have involved criticisms of the taxonomic data base, sampling intervals, chronometric time scales, and statistical methods used in previous analyses. The criticisms are reviewed in some detail and various new calculations and simulations, including one assessing the effects of paraphyletic taxa, are presented. Although the new data strengthen the case for periodicity, they offer little new insight into the deriving mechanism behind the pattern. However, they do suggest that many of the periodic events may not have been catastrophic, occurring instead over several stratigraphic stages or substages.
Document ID
20040121520
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
Authors
Sepkoski, J. J. Jr
(University of Chicago Illinois 60637, United States)
Sepkoski JJ, J. r.
Date Acquired
August 22, 2013
Publication Date
January 1, 1989
Publication Information
Publication: Journal of the Geological Society
Volume: 146
ISSN: 0016-7649
Subject Category
Geosciences (General)
Funding Number(s)
CONTRACT_GRANT: NAG2-282
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Number 52-40
Non-NASA Center
Review
Review, Tutorial
NASA Program Exobiology
NASA Discipline Exobiology

Available Downloads

There are no available downloads for this record.
No Preview Available