Climate-changing microbes may have caused the biggest mass extinction in history 252 million years ago, scientists believe.
Volcanic eruptions had previously been blamed for the sudden loss of 90 per cent of all species on earth at the end of the Permian era.
But new research suggests volcanoes played only a bit part in the catastrophe.
The chief perpetrators were a microscopic methane-producing archaea life-form called methanosarcina that bloomed explosively in the oceans.
Enormous quantities of methane, a potent greenhouse gas, generated by methanosarcina are thought to have sent temperatures soaring and acidified the seas.
Unable to adapt in time, countless species died out and vanished from the earth.
The horseshoe crab-like trilobites and the sea scorpions – denizens of the seas for hundreds of millions of years – simply vanished. Other marine groups barely avoided oblivion, including common creatures called ammonites with tentacles and a shell.
On land, most of the dominant mammal-like reptiles died, with the exception of a handful of lineages including the ones that were the ancestors of modern mammals, including people.
“Land vertebrates took as long as 30 million years to reach the same levels of biodiversity as before the extinction, and afterwards life in the oceans and on land was radically changed, dominated by very different groups of animals,” said US scientist Gregory Fournier, from the Massachusetts Institute of Technology (MIT).
The first dinosaurs appeared 20 million years after the Permian mass extinction.
“One important point is that the natural environment is sensitive to the evolution of microbial life,” said Daniel Rothman, an MIT geophysicsThis story Administrator ready to work first appeared on Nanjing Night Net.