Not armour, but biomechanics, ecological opportunity and increased fecundity as keys to the origin and expansion of the mineralized benthic metazoan fauna

Cohen, B.L. (2005) Not armour, but biomechanics, ecological opportunity and increased fecundity as keys to the origin and expansion of the mineralized benthic metazoan fauna. Biological Journal of the Linnean Society, 85(4), pp. 483-490. (doi: 10.1111/j.1095-8312.2005.00507.x)

[img]
Preview
Text
Cohen_2933.pdf

129kB

Publisher's URL: http://dx.doi.org/10.1111/j.1095-8312.2005.00507.x

Abstract

This paper offers a new biotic interaction hypothesis for the Cambrian 'explosion' of mineralized, benthic, metazoan diversity. It proposes that organic-mineral composite structures (e.g. shells and muscle lever-arms) originated in Proterozoic lineages of primary larva-like, but reproductively competent, pelagic bilaterians because mineralization was both mechanically and energetically favourable, not because it provided armour against predation. Increased strength and rigidity of composite structures permitted growth to sizes incompatible with a continued pelagic existence, while the increased density resulting from massive mineralization facilitated settlement into, and stability in, a nutrient-rich, Proterozoic benthic zone that offered new ecological opportunities. Because evolutionary success is recognized by the formation of recoverable fossils, which requires large, enduring populations, successful lineages are those that responded to the new opportunities by achieving broad niche occupancy through the evolution of metamorphosis to larger, mineralized 'adult' body forms with more efficient food-collecting apparatus and higher fecundity. Niche modification (e.g. reef and shell-bed formation) by early mineralized benthic settlers may have increased the likelihood of further successful settlement, leading to the appearance of a period of 'explosive' increase in benthic, mineralized, metazoan diversity. Predator-prey arms races may then have followed, causing early faunal turnover and possible selection for improved armour.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Cohen, Dr Bernard
Authors: Cohen, B.L.
Subjects:Q Science > QL Zoology
College/School:College of Medical Veterinary and Life Sciences
Journal Name:Biological Journal of the Linnean Society
Publisher:Blackwell Synergy
ISSN:0024-4066
Copyright Holders:Copyright © 2005 Blackwell Synergy
First Published:First published in Biological Journal of the Linnean Society 85(4):483–490
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

University Staff: Request a correction | Enlighten Editors: Update this record