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Environmental trends in extinction during the Paleozoic.
1Department of the Geophysical Sciences, University of Chicago, IL 60637, USA.
Science (New York, N.Y.)
|January 2, 1987
Summary
Paleozoic marine communities show increased extinction offshore, while individual genera extinction is higher onshore. This pattern reflects environmental stability influencing extinction rates across different taxa.
Area of Science:
- Paleontology
- Marine Ecology
- Stratigraphy
Background:
- Extinction patterns are crucial for understanding marine community dynamics and evolution.
- Environmental factors, such as proximity to shore, can significantly influence species survival.
- Previous studies suggest varying extinction sensitivities among different taxonomic groups.
Purpose of the Study:
- To investigate extinction intensity patterns in Paleozoic marine assemblages across environmental gradients.
- To determine if community-level extinction trends differ from those of individual taxonomic classes.
- To correlate extinction patterns with environmental predictability and stability.
Main Methods:
- Analysis of extinction intensities from 505 Paleozoic marine fossil assemblages.
- Classification of assemblages into six distinct environmental zones and 40 stratigraphic intervals.
- Comparison of extinction rates at both community and taxonomic class levels.
Main Results:
- Whole marine communities exhibited an increasing extinction rate moving offshore.
- Genera within individual taxonomic classes showed higher extinction rates in nearshore environments.
- The observed community-level trend is attributed to the distribution of taxa with lower extinction rates in nearshore zones.
Conclusions:
- Environmental stability plays a key role in marine extinction dynamics.
- Organisms in predictably stable environments (offshore) experienced lower extinction than those in fluctuating nearshore environments.
- Extinction patterns are scale-dependent, differing between whole communities and individual taxonomic groups.
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