Theory says complex life on Earth may be much older than thought

Scientists say they have found new evidence that supports their theory that complex life on Earth may have begun 1.5 billion years earlier than previously thought.

A team of researchers working in Gabon say they have found evidence deep within the rocks that suggests an animal habitat existed 2.1 billion years ago.

However, the researchers argue that the creature was restricted to inland seas and never spread across the planet, eventually becoming extinct.

This idea is a big departure from conventional thinking, and not all scientists agree.

Most experts believe that animal life began about 635 million years ago.

The study adds a new chapter to the ongoing debate over whether a previously unexplained layer discovered in Franceville, Gabon, actually represents fossils.

Scientists examined the rocks surrounding the formation to see if there was evidence of nutrients such as oxygen and phosphorus that could have supported life.

Professor Ernest Chi Hulu of Cardiff University worked with an international team of scientists.

He told BBC News that if his theory was correct, the organisms would have been similar to slime molds – brainless, single-celled organisms that reproduce by spores.

But Prof Graham Shields, from University College London, who was not involved in the study, said he had some concerns.

“I don’t disagree with the idea that nutrients were abundant 2.1 billion years ago, but I’m not convinced that this would have led to the diversification and formation of complex life forms,” ​​he said, suggesting that more evidence is needed.

Prof Chi Hulu said his research helped prove ideas about the process that created life on Earth.

“We’re saying here we have fossils, here we have oxygen, and that facilitated the emergence of the first complex life,” he said.

“We’re seeing the same processes that were present in the Cambrian period 635 million years ago and it helps to confirm that, ultimately helping us understand where we came from,” he added.

The first hint that complex life may have begun earlier than previously thought came about 10 years ago with the discovery of something called the Franceville Formation.

Prof Chi Hulu and his colleagues said the layer was made up of fossils and showed evidence of life that could “squish” around of its own accord.

The findings were not accepted by all scientists.

To find further evidence to support their theory, Professor Chi Hulu and his team analysed sediment cores drilled from rocks in Gabon.

Chemical analysis of the rocks has shown evidence that a “laboratory” for life was created shortly before the formation of the Earth’s layers.

The high concentrations of oxygen and phosphorus are thought to be the result of two continental plates colliding under the ocean, causing volcanic activity.

The collision caused some of the ocean water to be blocked off, creating a “shallow, nutrient-rich inland sea.”

Prof Chi Hulu said this protected environment provides the conditions that allow photosynthesis, resulting in the presence of large amounts of oxygen in the water.

“This would have provided enough energy to fuel the increased body size and more complex behaviors seen in the primitive, simple animal-like life forms found in fossils from this period,” he said.

But he also says that the isolated environment also led to the extinction of life forms because not enough new nutrients were provided to maintain the food supply.

Elias Rugen, a doctoral student at the Natural History Museum who was not involved in the study, agreed with some of the findings, saying it’s clear that “the cycling of carbon, nitrogen, iron and phosphorus in the oceans was a bit unprecedented at this point in Earth’s history.”

“It’s not impossible that complex life emerged and thrived 2 billion years ago,” he said, but added that more evidence was needed to support the theory.