But this was only one of the Big Five mass extinctions that the planet has experienced 3.5 billion years ago, and it was not the worst.
Now, scientists say they have identified evidence for a new mass extinction event in the fossil record, and it is one that has allowed dinosaurs to dominate the Earth for over 200 million years.
It takes place 232 million to 234 million years ago and has been called a Carbian Plavial episode.
“Until now, paleontologists had identified five ‘large’ mass extinctions over the last 500 million years of life history,” said the study’s co-author Geocopo dal coro, geologist at China University of Geosciences in Wuhan, in a news statement.
“Each of these had a profound impact on the development of the Earth and life. We have identified another great extinction event, and help to mark the modern form in reestablishing life on land and in the oceans. It had a major role to do. ” Ecosystems. “
The cause, the researchers said, was most likely a large-scale volcanic eruption in what is now Western Canada, where volcanoes ejected vast amounts of basalt and eventually formed much of the west coast of North America.
“The explosions were huge, they pumped large amounts of greenhouse gases like carbon dioxide, and were spikes of global warming,” Dal Corso said.
Climate change caused major loss of biodiversity in the sea and land. New groups created more modern-like ecosystems just after the extinction event. The change in climate encouraged the growth of plant life, and the expansion of coniferous forests – the evergreen evergreen trees we know today with needles and cones.
It was not just dinosaurs. Many modern groups of plants and animals also appeared at this time, including some turtles, crocodiles, lizards, and the first mammals.
According to the study, Carnian pluvial episodes also had an impact on marine life, with 33% of marine life being published in scientific forecasts. This led to the introduction of the type of coral reefs seen today, as well as many modern groups of plankton suggesting a profound change in the chemistry of the ocean after the mass extinction event.
Warming climate was also associated with increased rainfall, and it was found back in the 1980s as all had a humid episode for about 1 million years. “It was the emergent situation after the humid episode that gave dinosaurs a chance,” said study co-author Mike Benton. Professor of vertebrate paleontology at the University of Bristol in the United Kingdom in the statement.
“We now know that dinosaurs originated 20 million years before this event, but they remained quite rare and insignificant until the Carnival Plavial episode hit,” Benton said.
Alfio Alessandro Chiarenza, a paleontologist and research associate at University College London, said that while the study highlighted many important changes in life during this timeframe, he was “cautious in defining it as mass erasure.”
“Given the disparity of the fossil record, our information about biodiversity trends through time and space is often sharp,” he said via email.
He said, “Fossils may be ‘hidden’ in the rocks, which we still have not investigated or are simply not preserved for our days.”
Scientists typically define mass extinction as the disappearance of at least 50% of all species in a short period of time. Geologically, the period of time Generally less than 2.8 million years.
Benton told CNN that they could not yet estimate a figure for the loss of terrestrial life, but the incident would have affected widely varying ecological plants and animals around the world and in a short period of time. With the loss of substantial species.
The largest mass extinction event occurred 250 million years ago, wiping out 95% of all species and likely to be caused by a massive volcanic eruption in Siberia.