Scientists conclude different ‘Complex’ life forms may have existed on Earth before us

Scientists conclude DIFFERENT ‘Complex’ life forms may have once existed on Earth before our species came into existence.

“This research shows that there was enough oxygen in the environment to have allowed complex cells to have evolved…”

According to scientists, we are not the FIRST complex life forms on planet Earth. In fact, another complex life form existed once but disappeared at some point during Earth’s long history. Then, after a while, complex life forms reappeared.

Mainstream scholars agree that given our ‘current’ knowledge of Earth’s history, complex life appeared on our planet at least some 1.75 BILLION years ago.

A study conducted by scientists from the University of Washington (UW) tells a different story suggesting that around a billion years before life came into existence, complex life developed in Earth’s oceans.

A recent paper published in the in the Proceedings of the National Academy of Sciences –in which lead author Michael Kipp, a UW doctoral student in Earth and space sciences participated in— explored isotopic rations of Selenium located in sedimentary rocks in order to measure the presence of Oxygen in our planet’s atmosphere between 2 and 2.5 billion years ago.

Using Selenium as a tool, experts measured oxygen levels on Earth up to 2.5 billion years ago.

The results are fascinating and show that there was more than enough oxygen for complex life cells to develop on our planet.

Professor Roger Buick from the University of Washington and co-author of the study said:

“There is fossil evidence of complex cells that go back maybe 1 ¾ billion years, but the oldest fossil is not necessarily the oldest one that ever lived – because the chances of getting preserved as a fossil are pretty low.”

“This research shows that there was enough oxygen in the environment to have allowed complex cells to have evolved, and to have become ecologically important, before there was fossil evidence.

However, professor Buick warns not to jump to conclusions.

“That doesn’t mean that they did — but they could have.”

While this is not the first study which explored how much oxygen was present on Earth in the past, it does shed light on how selenium had been altered by the presence of large quantities of Oxygen and how it may have affected the appearance and possible disappearance of complex life on Earth.

In previous studies, scientists concluded that Oxygen appeared on our planet gradually through Earth’s history and it increased up to a level allowing complex life forms to exist.

“But what it looks like now is, there was a period of a quarter of a billion years or so where oxygen came quite high, and then sunk back down again,” Buick explained. This duration is important.

“Whereas before and after maybe there were transient environments that could have occasionally supported these organisms, to get them to evolve and be a substantial part of the ecosystem, you need oxygen to persist for a long time,” said lead author Michael Kipp.


Conditions right for complex life may have come and gone in Earth’s distant past.

Featured image: Tryingtofly

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