New research has revealed that it took the Earth over 10 million years to recover from its greatest mass extinction.
All life on the planet was nearly wiped out 250 million years ago, only 10 percent of plants and animals survived. It’s currently a matter of debate how quickly life recovered from this massive loss of biodiversity.
New evidence is suggesting a recovery that took 10 million years. This new research was done by Dr Zhong-Qiang Chen, from the China University of Geosciences in Wuhan, and Professor Michael Benton from the University of Bristol. It has just been published in the journal Nature Geoscience.
This extinction event, the end-Permian crisis, has been by far the most dramatic biological crisis to occur on the Earth. It was caused by a number of environmental changes: global warming, acid rain, ocean anoxia, and ocean acidification. These changes were enough to kill off 90 percent of the life on Earth.
Dr Chen said: “It is hard to imagine how so much of life could have been killed, but there is no doubt from some of the fantastic rock sections in China and elsewhere round the world that this was the biggest crisis ever faced by life.”
Research shows that further extinction events followed the first one for the next 5-6 million years, in waves. These were caused by repeated warming, oxygen, and carbon crisises.
A microbe-dominated ecosystem following the end-Permian event.
Some groups of animals showed signs of recovery after the first event, only to be wiped out by the following waves. And with so much biodiversity loss in ecosystems, boom-and-bust cycles of different organisms regularly occurred, leading to further extinctions.
Professor Benton, Professor of Vertebrate Palaeontology at the University of Bristol, said: “Life seemed to be getting back to normal when another crisis hit and set it back again. The carbon crises were repeated many times, and then finally conditions became normal again after five million years or so.”
After this long period of time, more complex ecosystems began to emerge. Some of the animals that appeared during this time, were the ancestors of crabs and lobsters, and the first marine reptiles. These new animals formed the basis of future ecosystems.
Professor Benton added: “We often see mass extinctions as entirely negative but in this most devastating case, life did recover, after many millions of years, and new groups emerged. The event had re-set evolution. However, the causes of the killing — global warming, acid rain, ocean acidification — sound eerily familiar to us today. Perhaps we can learn something from these ancient events.”
Source: University of Bristol