Translator Disclaimer
1 February 2003 The Ordovician Radiation: A Follow-up to the Cambrian Explosion?
Author Affiliations +
Abstract

There was a major diversification known as the Ordovician Radiation, in the period immediately following the Cambrian. This event is unique in taxonomic, ecologic and biogeographic aspects.

While all of the phyla but one were established during the Cambrian explosion, taxonomic increases during the Ordovician were manifest at lower taxonomic levels although ordinal level diversity doubled. Marine family diversity tripled and within clade diversity increases occurred at the genus and species levels. The Ordovician radiation established the Paleozoic Evolutionary Fauna; those taxa which dominated the marine realm for the next 250 million years. Community structure dramatically increased in complexity. New communities were established and there were fundamental shifts in dominance and abundance.

Over the past ten years, there has been an effort to examine this radiation at different scales. In comparison with the Cambrian explosion which appears to be more globally mediated, local and regional studies of Ordovician faunas reveal sharp transitions with timing and magnitudes that vary geographically. These transitions suggest a more episodic and complex history than that revealed through synoptic global studies alone.

Despite its apparent uniqueness, we cannot exclude the possibility that the Ordovician radiation was an extension of Cambrian diversity dynamics. That is, the Ordovician radiation may have been an event independent of the Cambrian radiation and thus requiring a different set of explanations, or it may have been the inevitable follow-up to the Cambrian radiation. Future studies should focus on resolving this issue.

Mary L. Droser and Seth Finnegan "The Ordovician Radiation: A Follow-up to the Cambrian Explosion?," Integrative and Comparative Biology 43(1), (1 February 2003). https://doi.org/10.1093/icb/43.1.178
Published: 1 February 2003
JOURNAL ARTICLE
7 PAGES

This article is only available to subscribers.
It is not available for individual sale.
+ SAVE TO MY LIBRARY

SHARE
ARTICLE IMPACT
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top