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Wonderful strife; systematics, stem groups, and the phylogenetic signal of the Cambrian radiation

Derek E. G. Briggs and Richard A. Fortey
Wonderful strife; systematics, stem groups, and the phylogenetic signal of the Cambrian radiation (in Macroevolution; diversity, disparity, contingency; essays in honor of Stephen Jay Gould, Elisabeth S. Vrba (editor) and Niles Eldredge (editor))
Paleobiology (June 2005) 31 (2, Suppl.): 94-112

Abstract

Gould's Wonderful Life (1989) was a landmark in the investigation of the Cambrian radiation. Gould argued that a number of experimental body plans ("problematica") had evolved only to become extinct, and that the Cambrian was a time of special fecundity in animal design. He focused attention on the meaning and significance of morphological disparity versus diversity, and provoked attempts to quantify disparity as an evolutionary metric. He used the Burgess Shale as a springboard to emphasize the important role of contingency in evolution, an idea that he reiterated for the next 13 years. These ideas set the agenda for much subsequent research. Since 1989 cladistic analyses have accommodated most of the problematic Cambrian taxa as stem groups of living taxa. Morphological disparity has been shown to be similar in Cambrian times as now. Konservat-Lagerstatten other than the Burgess Shale have yielded important new discoveries, particularly of arthropods and chordates, which have extended the range of recognized major clades still further back in time. The objective definition of a phylum remains controversial and may be impossible: it can be defined in terms of crown or total group, but the former reveals little about the Cambrian radiation. Divergence times of the major groups remain to be resolved, although molecular and fossil dates are coming closer. Although "superphyla" may have diverged deep in the Proterozoic, "explosive" evolution of these clades near the base of the Cambrian remains a possibility. The fossil record remains a critical source of data on the early evolution of multicellular organisms.


ISSN: 0094-8373
EISSN: 1938-5331
Coden: PALBBM
Serial Title: Paleobiology
Serial Volume: 31
Serial Issue: 2, Suppl.
Title: Wonderful strife; systematics, stem groups, and the phylogenetic signal of the Cambrian radiation
Title: Macroevolution; diversity, disparity, contingency; essays in honor of Stephen Jay Gould
Author(s): Briggs, Derek E. G.Fortey, Richard A.
Author(s): Vrba, Elisabeth S.editor
Author(s): Eldredge, Nileseditor
Affiliation: Yale University, Department of Geology and Geophysics, New Haven, CT, United States
Affiliation: Yale University, Department of Geology and Geophysics, New Haven, CT, United States
Pages: 94-112
Published: 200506
Text Language: English
Publisher: Paleontological Society, Lawrence, KS, United States
ISBN: 1-891276-49-2
References: 127
Accession Number: 2005-063036
Categories: Invertebrate paleontology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 plate
N24°40'00" - N24°40'00", E102°55'00" - E102°55'00"
Secondary Affiliation: American Museum of Natural History, USA, United StatesNatural History Museum, GBR, United Kingdom
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, Copyright, The Paleontological Society. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 200538
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