My research is focused on the early diversification of eukaryotic life, including the Proterozoic record of major protistan clades and the Ediacaran-Cambrian ‘explosion’ of animals. I am especially interested in exploring the macroecological and macroevolutionary divide that separates the first three billion years of (mostly microbial) life on Earth from the peculiarly macroscopic world of the Phanerozoic. The ability of tissue-/organ-grade animals to drive evolutionary arms races and build multi-trophic food webs undoubtedly lies at the core of this regime change, though reconstruction of the biogeochemical feedbacks and overall dynamics present ongoing multidisciplinary challenges. Exceptionally preserved, organic-walled fossils form the basis of much of my work, with an appreciation of taphonomic processes and delicate acid processing providing a regular flow of new material and palaeobiological insight.
Proterozoic palaeobiology - Ongoing work on pre-Cryogenian microfossil assemblages from arctic Canada, Montana and Svalbard are providing an increasingly resolved view of early eukaryotes, sex, multicelluarity and biomineralization. In the terminal Proterozoic, we have discovered a substantial new assemblage of Doushantuo-type microfossils in southern Norway (with Peter Adamson), and are developing new scanning and analytical techniques for interpreting Ediacaran/Avalonian macrofossil assemblages (with Emily Mitchell).
Cambrian palaeobiology - Our discovery of diverse Small Carbonaceous Fossils (SCFs) has introduced an important new category of data to the reconstruction of early Palaeozoic diversity. Although typically disarticulated, these 'micro-Burgess Shale-type fossils' are far more common than their macroscopic counterparts, offering a unique view of evolutionary diversification and ecological distribution through the Cambrian explosion and beyond. A 'Chengjiang-type' fossil biota in western Canada is providing a complementary macroscopic account.
Taphonomy of exceptionally preserved fossils - Our laboratory demonstration of pronounced sediment/mineralogy effects on the preservation of carbonaceous body fossils (with Lucy Wilson) points to a more nuanced understanding of secular changes in taphonomic pathways and palaeontological mega-biases. Comparison of Proterozoic-Cambrian SCFs and Burgess Shale-type fossils with comparably preserved fossils in the Miocene Clarkia biota promise further taphonomic and palaeobiological insight.
Macroecological and biogeochemical revolutions - The Neoproterozoic-Palaeozoic transition is marked by unprecedented shifts in biological diversity, marine ecology and redox geochemistry. Despite the current text-book view of a bottom-up, oxygen-triggered switch, recognition of biological hydrodynamics and the progressive, top-down impact of newly evolving animals points to a reversed causality. Like other technological innovations that transformed the planet, the belated appearance of animals was due not so much to the availabilty of raw materials as the developmental wherewithal to exploit them.
Recent publications can be found in the publications database here