Australia: The Land Where Time Began

A biography of the Australian continent 

Ediacaran-Cambrian Transition - Decoupling of Body Plan Diversification and Ecological Structuring: Evolutionary and Geobiological Feedbacks

According to the authors¹ the rapid appearance of bilaterian clades that occurred at the early Phanerozoic is one of the most intriguing topics in macroevolution, though the complex feedbacks between diversification and ecological interactions are still not well understood. In this study the authors¹ carried out a systematic and comprehensive analysis of the trace-fossil record of the Ediacaran-Cambrian transition, their results indicating that both the body plan diversification and ecological structuring were decoupled. By the Fortunian a wide repertoire of behavioural strategies and body plans had arisen. However, during Cambrian Stage 2 there had been a major shift in benthic ecological structure, with the establishment of a suspension-feeding infauna, a trophic web that had become more complex, and the coupling of benthos and plankton. Different styles of ecosystem engineering accompanied both phases, though the Phanerozoic ecology resulted from only the second one. The authors¹ suggest that the suspension-feeding infauna may have been the ecological drivers of a further diversification of deposit-feeding strategies by Cambrian Stage 3, which favoured an ecological spillover scenario. The Cambrian Explosion is strongly supported by trace-fossil information, though during the terminal Ediacaran-Fortunian allows for a short time of phylogenetic fuse.

Sources and further reading

1. Mángano, M. Gabriela, and Luis A. Buatois. "Decoupling of Body-Plan Diversification and Ecological Structuring During the Ediacaran–Cambrian Transition: Evolutionary and Geobiological Feedbacks." Proceedings of the Royal Society B: Biological Sciences 281, no. 1780 (April 7, 2014 2014).