Cyanobacteria, considered the first oxygen producers, appeared about 2.9 billion years ago. Despite actively engaging in photosynthesis, oxygen only began to accumulate in the atmosphere after a significant amount of time. Previously, scientists explained this by the binding of oxygen with rocks during chemical reactions.
However, the new research suggests that living organisms may have played an important role in this process. Scientists analyzed genetic sequences from thousands of modern species, allowing them to reconstruct the evolutionary history of the enzymes involved in aerobic respiration. The data indicate that soon after the emergence of cyanobacteria, other microorganisms began to actively utilize oxygen, preventing its accumulation in the atmosphere.
Fatima Husain, one of the co-authors of the study, noted that these results fundamentally change our understanding of the development of life on Earth and highlight how early organisms began to adapt to oxygen.
Additionally, it was previously reported about the probable natural formation of RNA molecules around 4.3 billion years ago. An international group of researchers described a six-stage process for RNA synthesis from simple organic compounds without external intervention, the results of which were published in the journal PNAS.
