A group of researchers has published its latest study in the journal Proceedings of the National Academy of Sciences. The research claimed that the oxygen content some 2.1 billion years back on Earth was likely the same as that through the Cambrian explosion.

The report revealed that the explosion dated back to around 542 years. Also, the major animal phyla, seemingly, appeared as a consequence of the same.

The team from University of Southern Denmark said that the claim has been made due to the fact that the advanced life and oxygen were unavoidably associated. It is, thus, that they could think about the appearance of living beings all of a sudden before the early Paleozoic Era.

It has been affirmed that it had the creatures not been able to grow skeletons or shells, their fossilization could not have been possible. The remains of these creatures were also implausible to be discovered in that case, said the report.

"We have examined rocks that are 2.15 billion - 2.08 billion years old. They show us that there was oxygen in deep water and thus also in the atmosphere at that time", said post-doctoral researcher, Emma Hammarlund, from Nordic Center for Earth Evolution (NordCEE).