A series of bizarre fossilized organisms off the coast of Africa suggests that complex life on Earth is over 1.5 billion years older than previously thought.
A new analysis of marine sedimentary rocks from the Franceville Basin off the western coast of Africa, deposited about 2.1 billion years ago, has revealed a world of ancient life that is “incredible.”
One of the 2.1 billion-year-old fossils recently excavated and the reconstructed image (right) – (Photo: Abderrazzak El Albani).
Previously, the consensus was that complex animals first appeared around 635 million years ago.
However, the offshore rock samples from Africa have hidden complex structured organisms, providing reasons for their existence on a planet that seemed extremely inhospitable 2.1 billion years ago.
These rock samples indicate an increase in phosphorus and oxygen in the seawater, which was entirely unexpected.
Earth scientist Ernest Chi Fru from Cardiff University (UK) explained: “We have known that the increase in phosphorus concentration in the sea and oxygen in seawater is related to a biological evolutionary event around 635 million years ago. Our study adds another event that occurred much earlier.”
This event, occurring 2.1 billion years ago, spurred certain organisms to achieve significant evolutionary leaps.
These include a large number of fossils so sizable that they can be seen without a microscope found in the Franceville Basin.
The wondrous ecosystem 2.1 billion years ago in today’s offshore Africa – (Graphic: Abderrazzak El Albani).
Previously, it was believed that all life forms before 635 million years ago were merely simple microorganisms.
The “missing” history of Earth’s biota has been rewritten: off the coast of Africa, 2.1 billion years ago, the nutrient-rich water combined with the collision of two ancient continents created an inland sea that was extremely conducive to life, even though it was isolated from the global ocean.
This facilitated a chemical process favorable for all species in those waters to undergo complex biological transformations.
They evolved dramatically in size and structure, resulting in a series of organisms with bizarre shapes that scientists have excavated.
However, the very isolation that created this attractive marine area also meant that this early developing ecosystem could not spread or survive to await another opportunity for evolutionary leaps.
In other words, our planet has regrettably missed out on 1.5 billion years of evolution.
If these organisms had not been isolated, Earth today might be dominated by a species even more advanced than ourselves.
These discoveries could indicate that complex life on Earth evolved in two separate phases: the first phase following the first significant increase of oxygen in the atmosphere 2.1 billion years ago and the second phase after a subsequent increase 1.5 billion years later.
Fortunately, the ecosystem from the second phase was lucky and evolved, developing into what we see today.
This fascinating study has just been published in the scientific journal Precambrian Research.
