On the freshwater ancestry of marine primary producers - Paul F. Hoffman скачать в хорошем качестве

On the freshwater ancestry of marine primary producers - Paul F. Hoffman

On the freshwater ancestry of marine primary producers: a snowball Earth legacy and implications for the pre-Cryogenian marine fossil record Paul F. Hoffman Molecular phylogenomic ancestral-state reconstruction suggests that many modern marine primary producers evolved in freshwater over most of their evolutionary history. This is surprising in view of the marine fossil record of cyanobacteria and algae back to at least 2.02 and 1.04 billion years ago, respectively. We can reconcile this apparent conflict by assuming that all modern organisms are derived from the survivors of Cryogenian snowball Earths, when phototrophy was limited to supraglacial meltwaters, meromictic ice-covered lakes, and certain hot springs. This suggests that most pre-Cryogenian marine fossils represent stem groups, lacking direct descendants in living taxa.