Apocalypse Nam. Scientists discover that the first mass extinction on Earth happened earlier
send to Telegram
share on Facebook < /li>
send to Viber
send to Whatsapp
send to Messenger
The study found evidence of what could have been the first mass extinction on the planet.
The Cambrian explosion is known to have occurred over 538 million years ago, giving rise to many animal species known to us today. Since then, the Earth has experienced five mass extinctions that have significantly reduced the biodiversity of the planet. However, a new study suggests that is not entirely true, writes Science Alert.
A group of scientists from the Virginia Institute of Technology, led by paleontologist Scott Evans, studied thousands of rare Ediacaran fossils of milder species from around the world. Researchers now suggest that the sudden changes in the planet's biodiversity were not just sampling errors, but evidence of an earlier mass extinction event on Earth.
At Focus. Technology has its own Telegram channel. Subscribe to keep up to date with the latest and most exciting news from the world of science!
In the course of research, scientists have found that between the early stage of the Ediacaran period, Avalon (575-560 million years ago), and the middle , stages of the White Sea (560-550 million years ago), the biodiversity of the planet has increased significantly.
Scott and his team found differences in diet, lifestyle, and body size between creatures from these two Ediacaran stages. Scientists believe that it was at this moment that a large number of small mobile animals appeared that fed on microbial mats that were on the seabed. Their earlier ancestors were generally sessile filter feeders.
However, everything changed between the stage of the White Sea and the last stage of the Ediacaran period, known as Nama (550 – 539 million years back). The study shows that between these two stages, another mass extinction occurred on the planet, reducing the number of species by a staggering 80%.
In earlier studies, scientists suggested that these changes could be related to the transition from sedentary filter feeders to mobile animals. However, the new study does not confirm this.
Scientists have found that only 14 animal genera out of 70 known groups of the White Sea stage are still found at the Nama stage. The researchers note that if the decline in biodiversity were the result of evolution, they would still be able to find a temporal coincidence. But this is not the case.
Evans notes that many of the animals that survived this mass extinction are fairly large animals with a high body surface area to volume ratio. The researchers suggest that this indicates that they were able to adapt to the decrease in oxygen in the ocean.
Another confirmation of this theory is a study in 2018, when scientists found that extensive ocean anoxia occurred at the end of the Ediacaran period, which affected more than 20% of the seabed.