An Oasis of Complex Life on Earth Amidst Chaos - 2 Billion Years Ago

Perhaps the first ancestors of animals appeared on our planet much earlier than we thought.

Scientists have discovered evidence that complex life forms may have emerged on our planet over two billion years ago. They existed in a secluded space but then went extinct, and a similar level of development was only reached another one and a half billion years later.

It is believed that life on Earth originated fairly soon after the formation of the planet, which occurred about 4.5 billion years ago. For example, direct evidence indicates that microbes existed as early as 3.5 billion years ago. However, for most of its existence, life on Earth consisted of single-celled organisms. It is thought that complex organisms, including the ancestors of modern animals, appeared only about 635 million years ago when conditions became favorable for increased body size.

But what if everything was different? Previously, scientists discovered mysterious flattened fossils up to 17 cm in size in the city of Franceville, located in eastern Gabon, which seem to be early multicellular organisms. The catch is that, according to researchers, these organisms lived 2.1 billion years ago—meaning they are about three times older than the life forms of a similar level that are commonly considered the oldest.

To better investigate this issue, scientists conducted a geochemical analysis of marine sedimentary rocks in the area where the fossils were found. They found evidence that oxygen and phosphorus were present in the Franceville area shortly before the controversial structures appeared. It seems that two very old and solid tectonic plate areas collided there, triggering a series of underwater volcanic eruptions. This, in turn, led to the formation of a shallow inland sea rich in nutrients.

But if complex life forms really originated one and a half billion years earlier than we thought, why is there no other evidence of this? According to scientists, the favorable conditions were limited to this inland sea, and beyond its borders, Earth was still hostile to complex life forms. Moreover, the oasis itself was short-lived from a geological perspective, so these creatures ultimately went extinct. A new chance for evolution to try again only arose 635 million years ago when conditions on the planet were more favorable.

Not all scientists agree with the conclusions of this study—nor with whether the structures from Franceville are indeed fossils. Additional research may be needed to confirm these claims. But if they are found, it could fundamentally change our understanding of life on Earth—and perhaps beyond it.