The first mass extinction was not what we thought

It is an invention Science It can upset many things: step A message studyThere will be a sixth Mass destruction On that day Earth, which would have happened before everyone else. We explain to you.

The sixth mass extinction is so far forgotten

Everyone knows that the influence of human activities is harmful to our planet. If the question is subject to debate, many scientists warn us and consider it We would have triggered a new cycle of mass destruction. The term is used to refer to a biological and/or ecological crisis that causes the disappearance of at least 75% of plant and animal species from the surface of the Earth and oceans over a few million years.

Today, it is generally accepted Earth has experienced five mass extinctions in its history. The most recent one, everyone has already heard about it: happened about 65 million years ago, which is most likely the cause of the disappearance of the dinosaurs. First, it would be due to a large glaciation and would date back 445 million years. At least that’s what we thought until today.

A recent study conducted by postdoctoral researcher Scott Evans, a professor at Virginia Tech (or “Virginia Polytechnic Institute and State University”), actually managed to reach that conclusion. The first major extinction was actually 550 million years ago, at the end of the Ediacaran era.

An oxygen deficient planet

The Ediacaran was a period in which many species flourished: it is from this period that we date the oldest traces of multicellular life. More than 80% of them have disappeared. Without knowing exactly why. For many researchers, this brutal event is the reason for the appearance of species that greatly disrupted the food chain. But the study we are talking about today says the oppositeIt was actually Earth’s first mass extinction.

This could have been caused by a sudden decrease in the amount of oxygen on our planet. However, the results of the study suggest that: Of the 70 studied species from 550 million years ago, only 14 are still living on Earth 10 million years later. Scientists have not found drastic differences in diet between surviving and extinct species, and do not consider them to be large enough to account for environmental changes. Some fossils have disappeared. for them, The reason is necessary due to a profound environmental change.

And what put them on the path to lower oxygen levels is that all the fossils found belong to animals with very similar species, often much larger, with more oxygen and less oxygen. However, researchers were unable to pinpoint the cause of this sudden disappearance. A large fraction of oxygen (volcanic eruption? Meteorite?…). However, they found it This phenomenon would be the origin of most of life as we know it todayOnly after this mass destruction Species appeared Near the earth’s inhabitants today.