Life On Earth May Have Evolved Around 3.5 Billion Years Ago, Study Finds

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In a recently published study by the Imperial College London, scientists have discovered that microbes could have performed oxygen-producing photosynthesis at least one billion years earlier in the history of the Earth than what scientists thought possible until now.

Image Credit: Comfreak / Pixabay

The new study tells us a lot about what life was like in Earth’s distant history, and how it evolved through time. 

As explained by scientists, the new study could forever change the way we think about complex lifeforms, and when they evolved on Earth. It also helps us understand how likely it is for life (as we know it) to have developed elsewhere in the solar system, or galaxy.

Oxygen, the key ingredient?

For complex life to exist on Earth, Oxygen is needed in our planet’s atmosphere. This element is used by lifeforms during aerobic respiration to make energy.

Earlier studies have shown that around 2.4 billion years ago, levels of oxygen dramatically rose in our planet’s atmosphere. However, experts could not agree on the reason why this happened.

There are some experts who maintain the spike in oxygen levels 2.4 billion years ago can be traced to organisms called cyanobacteria and when they first evolved.

As explained by scientists, these organisms were the first to perform oxygen-producing (oxygenic) photosynthesis on Earth.

But not everyone agrees.

Some scholars argue that cyanobacteria existed on Earth long before 2.4 billion years ago. But something occurred in the distant past that prevented oxygen accumulating in the atmosphere.

Cyanobacteria have the ability to perform a sophisticated form of oxygenic photosynthesis.

 In fact, it is the same type of photosynthesis that all planets on Earth do today. 

The new study published by scientists from Imperial College London argues that oxygenic photosynthesis came to be at least one billion years before cyanobacteria evolved.

Their findings were published in the journal Geobiology.

There, experts explain that oxygenic photosynthesis could have evolved very early in our planet’s history. This means that life could have also.

“We know cyanobacteria are very ancient, but we don’t know exactly how ancient. If cyanobacteria are, for example, 2.5 billion years old, that would mean oxygenic photosynthesis could have started as early as 3.5 billion years ago. It suggests that it might not take billions of years for a process like oxygenic photosynthesis to start after the origin of life,” explained the lead author of the study Dr. Tanai Cardona, from the Department of Life Sciences at Imperial.

“Our study instead shows that oxygenic photosynthesis likely got started long before the most recent ancestor of cyanobacteria arose. This is in agreement with current geological data that suggests that whiffs of oxygen or localized accumulations of oxygen were possible before three billion years ago,” experts concluded.

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