There’s still a lot we don’t know about the origin of life on Earth.
However, a recent breakthrough discovery might get us closer to a precise answer.
Most scientists agree that one of the best ways to find out when life as we know it started is go back and look for evidence of oxygenic photosynthetic structures.
In other words, to find out when the first organisms capable of turning sunlight into energy and oxygen appeared.
Scientists have discovered new fossilized bacteria from Australia and Canada that could potentially be capable of photosynthesis.
If confirmed, it would push back the origin of photosynthesis by 1.2 billion years.
This would mean complex life on Earth started 1.7 billion years ago.
The current consensus among scientists is that early organisms were capable of delivering a primitive form of photosynthesis, ie without actually producing oxygen, 3 billion years ago.
But it took a while to turn that into ‘modern’ photosynthesis.
Today, the vast majority of algae, bacteria and plants that photosynthesize make oxygen.
The key event that led to the creation of life was the so-called Great Oxygenation Event, which is when our gas dense atmosphere began filling with oxygen.
According to a study co-authored by Emmanuelle Javaux from the University of Liège in Belgium, this event was crucial because it began modifying the chemistry of Earth’s oceans and atmosphere.
To call it a complex matter would be an understatement.
So far, scientists have been able to establish with a significant degree of accuracy that the first organisms that we’d realistically call ‘animals’ appeared between 574 and 485 million years ago.
It gets more complicated when talking about humans.
Depending on how we define ‘humans’, some believe we appeared two millions years ago.
But if we are considering ‘modern’ humans, as in fully distinct from other primates, then we’re ‘only’ 200,000 years old.
It feels like progress in this field will be exponential.
What a time to be alive.
It’s only a matter of time before we find out when it all began.