Scientists believe what wiped out more than 90% of marine species and 75% of terrestrial species nearly 440 million years ago (Paleozoic-primary era) were massive volcanic eruptions. Now, a new study carried out by Vanderbilt University (USA) has solved this mystery, stating that massive volcanoes erupted hundreds of thousands of years before the largest extinction on the face of the Earth, so neither the meteorites nor the eruptions were the cause but rather the relentless evolution . This is the explanation.
The first organisms that ruled the Earth for more than 3 billion years were microbes. Subsequently, some of them discovered how to capture the energy of the sun, which gave them the necessary energy to adopt multicellular forms: the Ediacarans, the first complete life form on Earth . This happened about 600 million years ago in the era known as the Ediacaran Period.
“ We don’t know much about Ediacarans because they don’t produce shells or skeletons. As a result, almost everything we know about them comes from traces of their forms preserved in sand or ash ”, clarifies Simon Darroch, leader of the study that has examined the youngest known Ediacaran community, exposed in hillside strata in the south of Namibia, Swartpunt Farm.
These organisms spread all over the planet ; many were extremely passive and remained in the same place all their lives, absorbing chemicals from the water through their outer membranes to feed themselves, so the scenario that is drawn in this period must have been a haven of peace.
“ People have been slow to recognize that biological organisms can also drive mass extinction. But our comparative study of several communities of Ediacarans, the first multicellular organisms, strongly supports the hypothesis that it was the appearance of complex animals capable of altering their environments , which we define as ‘ecosystem engineers’, which led to extinction. of the Ediacárico ”, explains Darroch.
Evolution continued its course and after 60 million years animals began to move independently and feed on other organisms. We reached the Cambrian explosion with the appearance of vertebrates, mollusks, arthropods, jellyfish … all these new species changed the environment, increasingly hindering the survival of the Ediacarans.
“We found that the diversity of species at this site was much lower, and there was no evidence of greater ecological stress, than at comparable sites that are between 1 and 1.5 million years older,” reports Darroch, who presents a link more than patent between the evolution of these and the extinction of the Ediacarans .
“ There is a powerful analogy between the Earth’s first mass extinction and what is happening today. The late Ediacaran extinction shows that the evolution of new behaviors can fundamentally change the entire planet, and we are the most powerful ‘ecosystem engineers’ the Earth has ever known, ”concludes Darroch.
The study has been published in the journal Proceedings of the National Academy of Sciences (PNAS).
