Proterozoic microfossils and understanding complex eukaryotic evolution

NEWS - Eukaryotes have evolved and dominated the biosphere, encompassing the vast majority of living species and the vast majority of biomass. The early evolution of eukaryotes marked a turning point for life on Earth.

Biologically complex organisms diversified in the Proterozoic Eon over 539 million years ago and have been a fundamental question in evolutionary biology. Paleontologists have attempted to document the rise of eukaryotes with fossil evidence.

The Proterozoic record has provided important insights into this biological radiation for the past 70 years. However, the delicate and microscopic nature of subcellular features has made it difficult to fossilize early eukaryotes.

The chemical and genetic biomarker signatures of living eukaryotes today are the only complementary tools available to reconstruct the ancestry of eukaryotes. These data are used in parallel with molecular clocks and biomarkers from sedimentary organic matter to collectively enable researchers to reconstruct the timing and ecology of early eukaryote evolution.

“Exceptionally preserved Proterozoic microfossils are critical for interpreting, calibrating molecular clocks, and testing paleoecological hypotheses,” said Ross Anderson and George Wedlake of the University of Oxford and colleagues, and Sanaa Mughal of the University of Alberta.

“We highlight recent technologies and new approaches to biomolecular preservation and composition,” said said Anderson and colleagues.

Advances in understanding the taphonomy of early eukaryotes, methods for placing them on the tree of life, and unique paleobiological data offer the prospect of exploring Proterozoic microfossils with greater utility for documenting early eukaryotic evolution.

Eukaryota is the domain of life that sits above the Kingdoms in the taxonomic classification that includes Animalia, Archaea, Bacteria, Chromista, Fungi, Plantae and Protozoa. This domain refers to the popular descriptions by Édouard Chatton in 1925 and Robert Whittaker & Lynn Margulis in 1978.

Original research

Anderson Ross P., Mughal Sanaa and Wedlake George O. (2024). Proterozoic microfossils continue to provide new insights into the rise of complex eukaryotic life. Royal Society Open Science, 11240154, DOI:10.1098/rsos.240154

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