Earth (Photo Credit: NASA)
It is said that one day humans will extinct from the Earth. And yes, it will happen as we are destroying nature for our sake. There will be a day when nature will take back all from us. Do you know that around one billion years ago Earth suffered a major mass extinction? No, may be the answer from most of you. Well, whatever you read is right. In the pre-historic Silurian Period, 99.5 per cent of life on Earth was wiped out. Now, you must be wondering what could be the reason behind mass extinction. The reason had so far remained a mystery which is now revealed. Scientists have finally unearthed the reason behind this major mass extinction of Earth that took place one billion years ago.
According to a study published in PNAS, an international team of scientists examined rocks from Hudson Bay, Canada, that would have formed billions of years ago. They were looking at barite, a mineral that holds information about how much oxygen was in the atmosphere at a given time.
The scientists from these rocks were able to show that there was a massive drop in the level of life on Earth 2.05 billion years ago. Due to this, there were major changes in the oxygen levels on Earth. Yes, you read it right. About 2.4 billion years ago, there was a massive surge in the amount of oxygen in the atmosphere and this event is called as the Great Oxidation Event. At the end of the Great Oxidation Event, oxygen levels fell. Researchers say conditions for life on Earth went from "feast to famine"—and that these conditions persisted for about one billion years.
Study author Peter Crockford, from Israel's Weizmann Institute of Science and Princeton University, told Newsweek that they were very surprised. "We didn't expect to see such a large signal, nor did we expect to find it in this specific type of sample,” he added.
"Over the 100 to 200 million years before this die-off event there was a large amount of life on the planet, but after this event a huge portion died off. However, instead of recovering like more recent mass extinctions, the amount of life on the planet or size of the biosphere stayed small for the following billion years of Earth's history—about two billion to one billion years ago," Peter Crockford said.
He further said, "From our estimates it could be anywhere between about 99.5 per cent to 80 per cent of life on the planet died off around two billion years ago." To put that in perspective, the mass extinction event of the dinosaurs saw about three-quarters of life on Earth disappear, while the Great Dying event—the biggest known mass extinction—resulted in the loss of around 70 percent of terrestrial life and 96 percent of ocean dwellers.”