Low level of oxygen in Earth’s middle ages delayed evolution for 2 billion years

Related Articles

Related Articles

A low level of atmospheric oxygen in Earth’s middle ages held back evolution for 2 billion years, raising fresh questions about the origins of life on this planet.

New research by the University of Exeter explains how oxygen was trapped at such low levels.

Professor Tim Lenton and Dr Stuart Daines of the University of Exeter Geography department, created a computer model to explain how oxygen stabilised at low levels and failed to rise any further, despite oxygen already being produced by early photosynthesis. Their research helps explain why the ‘great oxidation event’, which introduced oxygen into the atmosphere around 2.4 billion years ago, did not generate modern levels of oxygen.

 

In their paper, published in Nature Communications, Atmospheric oxygen regulation at low Proterozoic levels by incomplete oxidative weathering of sedimentary organic carbon, the University of Exeter scientists explain how organic material – the dead bodies of simple lifeforms – accumulated in the earth’s sedimentary rocks. After the Great Oxidation, and once plate tectonics pushed these sediments to the surface, they reacted with oxygen in the atmosphere for the first time.

The more oxygen in the atmosphere, the faster it reacted with this organic material, creating a regulatory mechanism whereby the oxygen was consumed by the sediments at the same rate at which it was produced.

This mechanism broke down with the rise of land plants and a resultant doubling of global photosynthesis. The increasing concentration of oxygen in the atmosphere eventually overwhelmed the control on oxygen and meant it could finally rise to the levels we are used to today.

This helped animals colonise the land, leading eventually to the evolution of mankind.

The model suggests atmospheric oxygen was likely at around 10% of present day levels during the two billion years following the Great Oxidation Event, and no lower than 1% of the oxygen levels we know today.

Professor Lenton said: “This time in Earth’s history was a bit of a catch-22 situation. It wasn’t possible to evolve complex life forms because there was not enough oxygen in the atmosphere, and there wasn’t enough oxygen because complex plants hadn’t evolved – It was only when land plants came about did we see a more significant rise in atmospheric oxygen.

“The history of life on Earth is closely intertwined with the physical and chemical mechanisms of our planet. It is clear that life has had a profound role in creating the world we are used to, and the planet has similarly affected the trajectory of life. I think it’s important people acknowledge the miracle of their own existence and recognise what an amazing planet this is.”

Life on earth is believed to have begun with the first bacteria evolving 3.8 billion years ago. Around 2.7 billion years ago the first oxygen-producing photosynthesis evolved in the oceans. But it was not until 600 million years ago that the first multi-celled animals such as sponges and jellyfish emerged in the ocean. By 470 million years ago the first plants grew on land with the first land animals such as millipedes appearing around 428 million years ago. Mammals did not rise to ecological prominence until after the dinosaurs went extinct 65 million years ago. Humans first appeared on earth 200,000 years ago.

UNIVERSITY OF EXETER

Download the HeritageDaily mobile application on iOS and Android

More on this topic

LATEST NEWS

The Lost Town of Trellech

Trellech is a small rural village in south-east Wales, but during the 13th century, it was one of the largest medieval towns in all of Wales.

The Varangian Guard – When Vikings Served the Eastern Roman Empire

The Varangian Guard was an elite unit that served as the personal bodyguards for the emperors of the Byzantine Empire (Eastern Roman Empire).

Walking, Talking and Showing Off – a History of Roman Gardens

In ancient Rome, you could tell a lot about a person from the look of their garden. Ancient gardens were spaces used for many activities, such as dining, intellectual practice, and religious rituals.

Curious Kids: How did the First Person Evolve?

We know humans haven’t always been around. After all, we wouldn’t have survived alongside meat-eating dinosaurs like Tyrannosaurus rex.

Ring-like Structure on Ganymede May Have Been Caused by a Violent Impact

Researchers from Kobe University and the National Institute of Technology, Oshima College have conducted a detailed reanalysis of image data from Voyager 1, 2 and Galileo spacecraft in order to investigate the orientation and distribution of the ancient tectonic troughs found on Jupiter’s moon Ganymede.

Tracing Evolution From Embryo to Baby Star

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) took a census of stellar eggs in the constellation Taurus and revealed their evolution state.

“Woodhenge” Discovered in the Iberian Peninsula

Archaeologists conducting research in the Perdigões complex in the Évora district of the Iberian Peninsula has uncovered a “Woodhenge” monument.

New Fossil Discovery Shows How Ancient ‘Hell Ants’ Hunted With Headgear

Researchers from New Jersey Institute of Technology (NJIT), Chinese Academy of Sciences and University of Rennes in France have unveiled a stunning 99-million-year-old fossil pristinely preserving an enigmatic insect predator from the Cretaceous Period -- a 'hell ant' (haidomyrmecine) -- as it embraced its unsuspecting final victim, an extinct relative of the cockroach known as Caputoraptor elegans.

Popular stories

Port Royal – The Sodom of the New World

Port Royal, originally named Cagway was an English harbour town and base of operations for buccaneers and privateers (pirates) until the great earthquake of 1692.

Matthew Hopkins – The Real Witch-Hunter

Matthew Hopkins was an infamous witch-hunter during the 17th century, who published “The Discovery of Witches” in 1647, and whose witch-hunting methods were applied during the notorious Salem Witch Trials in colonial Massachusetts.

Did Corn Fuel Cahokia’s Rise?

A new study suggests that corn was the staple subsistence crop that allowed the pre-Columbian city of Cahokia to rise to prominence and flourish for nearly 300 years.

The Real Dracula?

“Dracula”, published in 1897 by the Irish Author Bram Stoker, introduced audiences to the infamous Count and his dark world of sired vampiric minions.