1.5 billion years more Complex life on Earth could be much older than thought

Complex life on Earth could have emerged 1.5 billion years earlier than previously thought. A team of researchers claims to have found new evidence for this revolutionary theory.

Complex life on Earth could be much older than previously thought. A research team from Cardiff University claims to have found evidence in Gabon, Central Africa, that complex creatures could have lived on Earth as long as 2.1 billion years ago, as they report in a study. That would be 1.5 billion years earlier than previously assumed.

The current scientific consensus is that complex organisms first appeared on Earth around 635 million years ago. However, the new theory now assumes a much earlier date. Study leader Ernest Chi Fru explains to the BBC that compounds of oxygen and phosphorus have been detected in rock samples: Nutrients that suggest the emergence of complex organisms.

"There are fossils here, there is oxygen here, and this is what promoted the emergence of the first complex creatures," explains Ernest Chi Fru. The same process can be observed as in the Cambrian 635 million years ago. Ultimately, the new findings would help "to understand where we all come from".

A "laboratory" for life

However, the scientist qualifies that the creatures were probably restricted to an isolated inland sea and therefore died out again. The first indication that complex life could have emerged earlier than previously assumed came about ten years ago with the discovery of the so-called Francevillian formation.

This formation consists of fossils that point to life that was able to "migrate" and move on its own. To find further evidence for their theories, they have now analyzed sediment cores that were drilled from the rock in Gabon.

The chemistry of the rock showed that a "laboratory" for life was created shortly before the formation was formed. The high oxygen and phosphorus content was probably caused by the collision of two continental plates under water and the resulting volcanic activity.

Reservations among scientists

However, the new theory has met with skepticism from other scientists. Graham Shields from University College London, for example, who was not involved in the research, expresses reservations. "I'm not against the idea that there were more nutrients 2.1 billion years ago, but I'm not convinced that this could have led to a diversification that gave rise to complex life," he says, calling for more evidence for the new theory on the origin of life.

Elias Rugen of the Natural History Museum London also said it was clear that "the oceanic carbon, nitrogen, iron and phosphorus cycles were doing something unprecedented at this point in the Earth's history". There is nothing to suggest "that complex biological life could have emerged as early as two billion years ago". However, Rugen also calls for more evidence to support the new theory.