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Early animal evolution: emerging views from comparative biology and geologyThe Cambrian appearance of fossils representing diverse phyla has long inspired hypotheses about possible genetic or environmental catalysts of early animal evolution. Only recently, however, have data begun to emerge that can resolve the sequence of genetic and morphological innovations, environmental events, and ecological interactions that collectively shaped Cambrian evolution. Assembly of the modern genetic tool kit for development and the initial divergence of major animal clades occurred during the Proterozoic Eon. Crown group morphologies diversified in the Cambrian through changes in the genetic regulatory networks that organize animal ontogeny. Cambrian radiation may have been triggered by environmental perturbation near the Proterozoic-Cambrian boundary and subsequently amplified by ecological interactions within reorganized ecosystems.
Document ID
20040141919
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Knoll, A. H.
(Harvard University 26 Oxford Street, Cambridge, MA 02138, United States)
Carroll, S. B.
Date Acquired
August 22, 2013
Publication Date
June 25, 1999
Publication Information
Publication: Science
Volume: 284
Issue: 5423
ISSN: 0036-8075
Subject Category
Geosciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
Non-NASA Center
NASA Discipline Exobiology
Review, Tutorial
Review

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