Lyell Meeting 2013
The Cambrian Explosion: Understanding Earth Systems at the Origin of Modern Ecosystems
The meeting was focused on anyone interested in complex feedback processes within Earth systems, as well as those with a direct interest in the Ediacaran–Cambrian transition.
As consensus begins to emerge on the topology of high-level phylogenetic relationships amongst animal groups, molecular clocks are beginning to elucidate the slow fuse versus big bang debate relating to the origin of major animal groups, and it is now clear that the major animal clades diverged tens of millions of years before their first appearance in the fossil record.
Understanding this macroevolutionary lag requires a multidisciplinary understanding of Cambrian Earth systems, in which a complex interplay of sea-level change, ocean geochemistry, biomineralisation and ecosystem engineering producing the major evolutionary diversification that characterises the early Cambrian. This involves a change from matground dominated ecosystems in the Ediacaran to the primitive but recognisably modern ecosystems associated with the Cambrian substrate revolution. Contemporaneously, the repeated but approximately synchronous evolution of biomineralisation in animal groups in the early Cambrian led to the first skeletons, and the selective opportunities provided by these novel structures.
This meeting brought together palaeobiologists, ichnologists, geneticists, geochemists and stratigraphers to re-assess the complex, non-uniformitarian processes that operated in ecosystems before, during and after the Cambrian Explosion. One aim was to examine the varied feedback processes operating in these ecosystems and the changes that occurred across the Ediacaran–Cambrian boundary. In addition, recent suggestions of underlying mechanisms for these changes were examined, including the Great Unconformity hypothesis that invokes the reworking of continental regolith during early Cambrian sea-level rise, transgression and continental inundation as an environmental trigger for the evolution of biomineralisation.