One of the coolest things about science can also be one of the most frustrating – and it’s that we’re always learning and discovering, so literally everything is subject to change.

Including, it would seem, how life emerged on this planet in the first place.

The same scientific theory that explains the Precambrian Avalon explosion – the era around 800 million years ago when multicellular organisms began to reproduce in Earth’s oceans – has been around for decades.

It posits that an increase in oxygen in the oceans sped up the evolution of complex life and eventually led to the complex and diverse biosphere we know today.

This recently published study suggests that could be wrong, though, because of some ancient rock samples.

Christian Bjerrum, a professor of geosciences and natural resource management at the University of Copenhagen explains why.

“The fact that we now know, with a high degree of certainty, that oxygen didn’t control the development of life on Earth provides us with an entirely new story about how life arose and what factors controlled this success.”

And yes, that means a lot of sweeping changes across the board.

“Specifically, it means that we need to rethink a lot of the things that we believed to be true from our childhood learning. And textbooks need to be revised and rewritten.”

To come to this conclusion, scientists mapped out the geochemical makeup of ancient rock samples from the Omani mountain range. The sample compositions revealed no major flood of oxygen at all – in fact, they concluded that, during that era, there was probably less oxygen in the Earth’s oceans.

“Our measurements provide a good picture of what average oxygen concentrations were in the world’s oceans at the time. And it’s apparent to us that there was no major increase in the amount of oxygen when more advanced fauna began to evolve and dominate Earth. In fact, there was somewhat of a slight decrease.”

They still think the oxygen levels could be important, just that it’s the decrease, not an increase, that led to the explosion of life.

“It’s interesting that the explosion of multicellular organisms occurs at a time with low concentrations of atmospheric and oceanic oxygen. That indicates that organisms benefitted from lower levels of oxygen and were able to develop in peace, as the water chemistry protected their stem cells naturally.”

Check out the video:

We’ll have to wait and see what peer reviews have to say.

But it does appear that an expensive textbook overhaul is on the horizon.