Accounting for uncertainty in the evolutionary timescale of green plants through clock-partitioning and fossil calibration strategies

Author: Bojian Zhong  

Organization:School of Life Sciences

Form of Achievement:journal paper

Introduction:this research was published in Systematic Biology, one of the top journals in the field of evolutionary biology (5-year comprehensive impact factor is 10.48). Green plants are one of the ancient photosynthetic eukaryotes, which play an important role in the global climate system. Due to the incomplete preservation of early green plant fossils and the lack of analytical methods, the timing of the origin of green plants and the divergence of major clades within this group remain highly controversial. Considering many uncertain factors affecting the estimation of divergence time, Bojian Zhong's research group used the method of Bayesian molecular dating to reconstruct the evolution timeline of green plants, estimating that those are originated from the Proterozoic to the Mesoproterozoic (1.68-1.09 billion years ago). This research reveals that during the period from Mesoproterozoic to Neoproterozoic (1.20-750 million years ago), the surging of green algae increased the emission of dimozide, and then that was oxidized into cloud condensation nuclei, which caused global air temperature dropping and promoted the formation of a "snowball-earth". This research has important theoretical value for understanding the relationship between green plants and the global climate system.