Fig. 1.

Importance of plant terrestrialization. (A) Biomass distribution on earth according to Bar-On et al. (2018. (B) Change in the atmospheric oxygen level during earth history. Reprinted by permission from Springer Nature. Lyons et al. (2014). The rise of oxygen in Earth’s early ocean and atmosphere. Nature 506, 307–315. Copyright 2014. Broken lines: alternative scenarios; GO, great oxygenation event. Possible ages for eukaroytes, primary plastids, and plant terrestrialization are indicated. (C) Chara vulgaris a representative of the Charophycae, which has often been suggested to be the sister of land plants. Zygnema circumcarinatum and Micrasterias crux-melitensis represent the filament and unicell life forms of the Zygnematophyceae, the sister clade to land plants. Image of Micrasterias crux-melitensis courtesy of Dr Monika Engels, Hamburg; with permission.