Tag Archives: permian

252 million years ago, climate change nearly wiped out life on Earth; something similar is happening today

Great climatic changes triggered the Earth’s biggest extinction, which wiped off 70% of terrestrial life and 96% marine life 252 million years ago, a new study suggests. A similar process seems to be taking place today, researchers warn.

The barbary ape is one of the many creatures currently threatened by extinction as a result of human action.

Then…

We’re 252 million years in the past, in a period called the Permian. Almost all of the Earth’s landmass is clumped together into a supercontinent called Pangaea. Although it’s still in its earlier phases, life on Earth has developed to be remarkably diverse. But evolution was about to suffer a massive setback — a dramatic extinction that came to be known as “The Great Dying.”

“It was a huge event. In the last half a billion years of life on the planet, it was the worst extinction,” said Curtis Deutsch, an oceanography expert who co-authored the research with University of Washington colleague Justin Penn and Stanford University scientists Jonathan Payne and Erik Sperling.

Despite the magnitude of this event, researchers have found relatively few clues about it — until some 20 years ago.

The problem is that 252 million years is a long time (even in geological terms), and finding reliable evidence that survived the onset of this much time is not easy. However, modern dating techniques (particularly the U–Pb dating of zircon crystals) allowed geologists to pinpoint this extinction to a few thousands of years — which given the scale of things, is quite impressive.

Similarly, radiometric studies have revealed that the extinction coincided with (and was likely caused by) massive volcanic eruptions. However, not all was clear. Specifically, it was unclear how the volcanic eruption and the extinction event were related.

Now, a new study suggests that the determining mechanism was an all too familiar one: climate change.

Image credits: University of Washington.

Essentially, the eruptions caused intense and abrupt global warming, which in turn depleted the oxygen from the oceans, causing the ocean’s creatures to effectively suffocate. Using a complex model powered by a supercomputer, the authors found that the combination of these two factors alone (warming water and low oxygen) can “account for more than half the magnitude of the ‘Great Dying’”.

If those two factors seem somewhat familiar, it’s because they’re also taking place today.

… and now

The story seems remarkably similar to what we’re experiencing today, as researchers themselves underline in the study.

“Voluminous emissions of carbon dioxide to the atmosphere, rapid global warming, and a decline in biodiversity—the storyline is modern, but the setting is ancient,” Penn State geosciences professor Lee Kump, who was not part of the research team, wrote in a Science piece responding to the new findings.

Indeed, it’s stunning how similar the two situations are. In both cases, an event caused temperatures to rise in a relatively short amount of time — but whereas 252 million years ago that was a volcanic eruption, in this case, it’s the greenhouse gas emissions outputted by mankind.

“The ultimate, driving change that led to the mass extinction is the same driving change that humans are doing today, which is injecting greenhouse gases into the atmosphere,” Justin Penn, a University of Washington doctoral student in oceanography and the study’s lead author, told the Seattle Times.

“The study tells us what’s at the end of the road if we let climate [change] keep going,” warned Curtis Deutsch, Penn’s co-author and PhD adviser, as the latest projections show emissions hitting record-breaking levels this year. “The further we go, the more species we’re likely to lose… That’s frightening. The loss of species is irreversible.”

Scientists are also tracking oxygen depletion in the oceans, and have reported some worrying trends, which already start to resemble what was happening in the late Permian.

[panel style=”panel-danger” title=”Greenhouse gases” footer=””]The extinction event likely occurred over a timeframe of tens or hundreds of years, during which Earth’s temperatures increased by around 10°C (18°F). Oceans lost around 80% of their oxygen, and many parts of the seafloor became completely oxygen-free. This warming was almost certainly caused by a huge spike in greenhouse gas emissions, caused by volcanic activity.

[/panel]

Simply put, we may be witnessing the start of another catastrophic period for Earth’s biodiversity, and contrary to popular belief, life doesn’t necessarily “bounce back” — it may be permanently affected. Previous studies have indicated that it took life at least 4-6 million years to recover after the Great Dying, while other authors put that figure towards 30 million years.

Credits: NASA.

Another striking similarity between the Great Dying and modern times is the devastation of insect populations. The ancient extinction is the only known mass extinction of insects — and insect populations have declined dramatically in the past few decades — the blink of an eye, in geological time.

If this all seems a bit alarming, well, it should. Finding so many similarities between the world’s greatest extinction event and today’s times is not something to be happy about. If our greenhouse gas emissions are not curbed, life on Earth (including humans) may be irreparably damaged.

“As our understanding of the drivers and consequences of end-Permian climate change and mass extinction improves,” Kump wrote, “the lessons for the future become clear.”

Within the Paris Agreement, countries pledged to reduce emissions and limit global warming to a maximum of 2 degrees Celsius over the pre-industrial levels, but globally, action has been lackluster, and several studies have found that an increase of over 4 degrees Celsius is much more likely.

World leaders are currently meeting in Katowice at the annual UN climate summit (in which the Paris Agreement was also signed) to decide the best course of action, but despite some remarkable initiatives, there are few reasons for optimism.

It’s easy to feel powerless in the face of such massive processes, but it’s important to remember that collectively, our decisions are one of the most powerful geological forces in our planet’s history. Your decisions do matter — make it count.

The study “Climate change and marine mass extinction” has been published in Science.

Fossil Friday: Helicoprion

Helicoprion bessonovi fossil, housed at The Idaho Museum of Natural History’s Earth Science collection.
Image via imnh

Helicoprion is an extinct genus of shark-like, cartilaginous fish that lived from the early Permian (~290 m.y. ago) all through to the massive Permian-Triassic extinction episode (roughly 250 m.y. ago.)

Their most distinctive characteristic, the lower jaw, baffled scientists for over a hundred years. This “tooth-whorl” structure was the only bony tissue to be found in the animal’s body, and the only part of it that fossilizes under normal conditions — so for all this time, paleontologists didn’t have enough context to describe it beyond “round…thingy. With teeth!”

In 2011 IMNH researchers performed a CT scan on an exceptionally well preserved specimen that contained the elusive jaws. The research eventually led to the first accurate reconstruction of the shark as well as placing in its proper position on the great tree of life.

The CAT scans also allowed a partial reconstruction of the rest of the animal, estimated to have been 3-4 meters (9.8 to 13.1 feet) long, but some potentially grew to almost 7.5 meters (24.6 feet) long. As their jaws aren’t resilient enough to break shells, Helicoprion most likely dined on soft prey, such as mollusks.

Treasure trove of Permian fossils discovered in Brazil

An international team of archaeologists unearthed a treasure trove of reptile and amphibian fossils in the Parnaiba Basin of north-eastern Brazil. The fossils are some 278 million years old, corresponding to the Permian period, when all the continents we know today were still fused together.

This illustration shows the two new amphibian species, T. anneae (left) and P. nazariensis (right), with one of the larger “rhinesuchidae” lurking in the background.
Image via bbc

Among the findings were two new species of “dvinosaurs,” ancient relatives of modern salamanders measuring about 40 centimeters in length, with preserved fangs and gills. South America’s oldest ever terrestrial reptile skeleton was also retrieved from the site.

Very little is currently known of the fauna and flora of the southern tropical regions of Pangaea during the Permian. Fossil finds for this period are exceedingly rare, and researchers are anxious to fill the gaps in the evolutionary history of the area. But it may be that this last fossil — of a lizard-like creature named Captorhinus aguti — that may be the crowning jewel of the site:

Previously only found in North America, discovering C. aguti here allows scientists to better understand the Permian era — up to now, it was described predominantly by North American and European fossils.

“This discovery is remarkable as most of what we understand about the evolution and adaptation of amphibians through time is based on animals located in Europe and North America,” said Dr Martha Richter from the Natural History Museum in London.

“Now that we know that their distant relatives inhabited a vast lake system in the tropical region of the super continent Pangaea… we can find out more about their abundance, paleontology, and how wide their distribution away from the equator was,” she concluded.

The researchers described one of the newly found fang-and-gill amphibian, dubbed Timona anneae, as being like a cross between a Mexican salamander and an eel.The other amphibian, Procuhy nazariensis, was probably closely related to it but fewer bones have been found and its anatomy remains unclear.

Both species appear to have spent their entire lives in the water.

The team also recovered skull remains belonging to another, much larger amphibian, part of the rhinesuchidae family described up to now in South African fossils. The animal was about as big as a medium-sized dog, scientist report.

The skull of Timonya anneae is just a few centimetres across.
Imaeg via bbc

This variety of fossils help researchers get an idea of how prehistoric animals dispersed and evolved.

“Fossils from classic areas in North America and Europe have been studied for over a century, but there are long-standing questions about how different animal groups dispersed to other areas,” said another of the paper’s authors, Dr Ken Angielczyk from the Field Museum in Chicago, US.

“Exploration in understudied areas, such as north-eastern Brazil, gives us a snapshot of life elsewhere that we can use for comparisons. In turn, we can see which animals were dispersing into new areas, particularly as an ice age was ending in the southern continents and environmental conditions were becoming more favorable for reptiles and amphibians.”

We’re heading towards a sixth major extinction

Species on Earth are disappearing at a never-before seen rate in human history. The stark threat hangs over all species – mammals, reptiles, birds, insects – and researchers are still trying to figure out the extent of this potential mass extinction. Now, a new analysis conducted by Naturfound that 41% of all amphibians on the planet now face extinction while 26% of mammal species and 13% of birds are similarly threatened.

Image via Nature. Download a PDF for the graphic.

Major Extinctions

The most devastating extinction ever took place some 252 million years ago, during the Permian – the last period of the Paleozoic. In the Permian extinction, an estimated 96 percent of marine species and 70 percent of life on land became extinct following a yet unconfirmed series of cataclysmic events. In Earth’s history, there have been five major mass extinctions – periods when the extinction rate is much higher than the natural, background rate. The first one to occur was the Ordovician–Silurian extinction about 440 million years ago, and the last one is Cretaceous–Paleogene extinction event, 66 million years ago – the extinction that wiped out the dinosaurs. All the major extinctions are associated with catastrophic events. This time, it’s different.

extinction species

The five major extinctions. Many scientists believe we may be heading towards a sixth, man-drive mass extinction. Image via University of New England.

Never in the history of the Earth has a species been so dominant as humans; we are changing the entire planet accoring to our needs, and this is having a huge effect on other species. From the massive deforestation to intensive agriculture which are destroying millions of square miles of animal habitat and to the introduction of invasive species and driving climate change, humanity is pushing the Earth towards a sixth great extinction.

“Habitat destruction, pollution or overfishing either kills off wild creatures and plants or leaves them badly weakened,” said Derek Tittensor, a marine ecologist at the World Conservation Monitoring Centre in Cambridge. “The trouble is that in coming decades, the additional threat of worsening climate change will become more and more pronounced and could then kill off these survivors.”

Human Driven Extinction

The endangered Indian pangolin, or thick-tailed pangolin (Manis crassicaudata), lives in south Asia, where hunters have targeted the animal for its meat and scales, which are used in traditional medicines.
Francois Savigny/NPL

Some 1.7 million species described by scientists, but we still don’t know exactly how many species there are in total. Estimates range from 2 to 50 million. The problem is that researchers have so far sampled only a sliver of Earth’s biodiversity, and most of the Earth’s species reside in a limited habitat – often times the very habitats which are most threatened, like the Amazon rainforest or areas of the ocean. It’s very hard to paint an accurate broad picture.

“That is the real problem we face,” added Tittensor. “The scale of uncertainty is huge.”

In other words, we know that we’re driving a huge chunk of animal and plant biodiversity extinct… we just don’t know exactly how big that chunk is. However, it’s clear that we need to change our ways if we want to prevent this disaster. Conservation policies could slow down extinctions, but this is not the long term solution we should be looking for.

“In general, the state of biodiversity is worsening, in many cases significantly,” says Derek Tittensor, a marine ecologist with the United Nations Environment Programme’s World Conservation Monitoring Centre in Cambridge, UK.

This means that what we should be looking for is sustainable change. In other words, we need to change our ways for good, and not just do things to mend our wrongdoings. The two main areas we should focus on are agriculture and overfishing – because this time it’s not a meteorite, it’s not a volcano, it’s not a cataclysm – we’re basically overeating biodiversity, with climate change being the icing on the cake.

The golden-crowned sifaka, or Tattersall’s sifaka (Propithecus tattersalli), of Madagascar is critically endangered. Habitat destruction and hunting have caused its population to decline since it was first discovered in 1974.
Nick Garbutt/naturepl.com

“In the case of land extinctions, it is the spread of agriculture that has been main driver,” added Tittensor. “By contrast it has been the over-exploitation of resources – overfishing – that has affected sealife.” On top of these impacts, rising global temperatures threaten to destroy habitats and kill off more creatures.

The analysis published in Nature paints a grim picture, but it also highlights what we need to do. First of all, we need to get an accurate picture of what’s happening – for this, governments and international organizations like the International Union for Conservation of Nature have to start a giant census; it may not be the exciting step, but we have to do it – only then can we understand what are the most adequate and effective measures.

Also, it’s vital to remember that we are not just harming biodiversity – we’re harming ourselves. As ecologist Paul Ehrlich puts it:

“In pushing other species to extinction, humanity is busy sawing off the limb on which it perches.”

 

300 million year old shark nursery found

Imagine salmon in reverse: long-snouted Bandringa sharks migrated downstream from freshwater swamps to a tropical coastline to spawn 310 million years ago – leaving behind a fossil nursery, which researchers found.

The bandringa sharks

bandringa shark

The surprising conclusion was drawn by University of Michigan paleontologist Lauren Sallan and a University of Chicago colleague; they analyzed every known specimen of Bandringa, a bottom-feeding predator that lived in an ancient river delta system in what is today the Upper-Midwest (keep in mind though that the face of the Earth was very different at the time, due to tectonic shifts).

This is the earliest example of shark migration, and so far, it is the only example of a freshwater to saltwater shark migration, as well as the earliest example of a shark nursery where fossilized egg cases and juvenile sharks were preserved in the same sediments; paleontologically, it’s a monumental find.

“This pushes migratory behavior in sharks way back,” said Sallan, an assistant professor in the U-M Department of Ecology and Evolutionary Biology. “These sharks bred in the open ocean and spent the rest of their lives in fresh water. No shark alive today is known to do that.”

How the continents looked like 250 million years ago.

The Bandringa shark (which currently doesn’t even have a Wikipedia entry) is likely one of the earliest close relatives of modern sharks. It greatly resembles today’s sawfish and paddlefish, with a spoon-billed snout up to half its body length. When they were fully grown, they could reach sizes of over 3 meters (approximately 10 feet). The first fossil specimens were discovered in 1969, and since then, they became one of the most prized specimens. They lived exclusively in freshwater swamps and rivers, according to Sallan and Michael Coates from the University of Chicago. If their conclusions are correct, then bandringa females traveled downstream to the shallow tropical coastline to lay their eggs in the salt water – a reverse situation from today’s salmon migration.

A shark nursery

Initially, it was thought that the Bandringa was actually two species – one that lived in saltwater, and another that lived in freshwater. But Sallan and Coates showed that Bandringa was a single species that lived, at various times during its life, in fresh, brackish and salt water.

Most sharks are ovoviviparous, as opposed to fish, which are generally oviparous; this means that instead of laying the eggs in the water, the eggs hatch in the oviduct within the mother’s body and that the egg’s yolk and fluids secreted by glands in the walls of the oviduct nourishes the embryos. However, bandringa was oviparous.

All the Bandringa fossils from the Mazon Creek marine sites are juveniles, and they were found alongside egg cases – the protective capsules that enclose the eggs. The females came, they laid their eggs and then left – that’s why no mature fossils were found. Meanwhile, the juveniles spawned from their eggs and tried to make their way upstream. Some made it, some didn’t.

“This is the first fossil evidence for a shark nursery that’s based on both egg cases and the babies themselves,” Sallan said. “It’s also the earliest evidence for segregation, meaning that juveniles and adults were living in different locations, which implies migration into and out of these nursery waters.”

Journal Reference:

  1. Lauren Cole Sallan, Michael I. Coates. The long-rostrumed elasmobranchBandringaZangerl, 1969, and taphonomy within a Carboniferous shark nursery. Journal of Vertebrate Paleontology, 2014; 34 (1): 22 DOI: 10.1080/02724634.2013.782875

Bus sized Triassic marine monster sheds light on ecosystems

A new species of “sea monster” was unearther in Nevada – a predator so fierce that it often hunted prey as big or bigger than itself.

ichthyosaurus-sea-monster-secrets-revealed_62934_600x450

Thalattoarchon saurophagis translates into “lizard-eating sovereign of the sea” – and boy is that a good name. It measured well over 8 meters and lived some 244 million years ago, during the Triassic, before the Jurassic period. The creature was an early ichtyosaur, giant marine reptiles that resembled dolphins but were the dominant marine predators for tens of millions of years.

Paleontologists from the Berlin’s Museum of Natural History said the fossil is unusually well preserved, maintaining its skull, fins, and entire vertebral column.

“It is pretty amazing, particularly for an animal this size,” said Fröbisch, who is also a National Geographic explorer.

ichtyosaur fossil

Ichtyosaur fossil

If Thalattoarchon would have any equivalents today, those would be sharks and killer whales (oracas). But what’s truly interesting about the fossil is that it shows how species and even ecosystems could bounce back from the most catastrophic event.

Nature’s struggles

“This animal occurs only eight million years after the biggest mass extinction event in Earth’s history, the Permian extinction, which literally wiped out up to 95 percent of all the species in the ocean,” Fröbisch explained. “The ocean was a pretty empty place afterward.”

permian_extinct5_hThe Permian extinction was indeed the most tragic event in our planet’s history; it occured 252.28 million years ago and its exact cause (or causes) are still unknown. It was a key moment for all life on Earth, much more difficult than the event that wiped out the dinosaurs 65 million years ago. But fossil records showed that life quickly bounced back after this event, despite all odds.

Where does Thalattoarchon fit in ? Well, when ecosystems bounce back, they bounce from the bottom up. If a top predator like itself appears, that means there’s a whole lot of food for it available, which means that the ecosystem has pretty much recovered; to put it another way, top predators are the last ones to reemerge.

“So with the appearance of Thalattoarchon we know it was complete and that it had the same structure as modern ecosystems, the same structure we’ve seen in place, with different players, ever since.”

Despite thriving for over 160 million years as the top predator, Thalattoarchon and his fellow ichtyosaurs vanished without a trail, without leaving any indication as to what led to their demise, and without leaving any descendants.

“Toward the end of the Cretaceous, they declined more and more, and their diversity also declined—and then they finally disappeared,” Fröbisch said.

It’s actually possible that at one point, they became too good for their own sake – virtually eliminating all the food sources available.

Via National Geographic

Triassic fossil of an eel-like conodont. (c) Yadong Sun.

During the greatest mass extinction in Earth’s history the world’s oceans reached 40°C – lethally hot

Between 247 to 252 million years ago, Earth life was going through quite possibly its most dire time. During this period some 90% of world’s species were wiped out, but what puzzled scientists for so long is the fact that it took five million years for life to recover after this apocalypse. A new study conducted by an international team of scientists found why it took so long – it was literally too hot to survive.

During what’s now commonly known as the end-Permian mass extinction, the Earth was a massive barren landscape. The die-off not only wiped out most marine and terrestrial animals, but plants too, which ensued a vicious circle. Plants absorb carbon dioxide, preventing the atmosphere from getting warmer, but as these died off in term as well, temperatures rose even higher too lethal levels. Other mass extinction periods took a few hundred thousand years for life to recover to previously similar levels, however this pre-Triassic extinction trialed life on Earth like never before – it needed five million years to surface.

pre-permian mass extinction

Earth at this time was a very peculiar world. The tropics would have a wet climate, much like today, but with no forests, only shrubs and ferns. Shellfish were the only marine creatures in the oceans. Virtually no land animals existed because their metabolisms would not have withstood such high temperatures. Only the polar regions offered a habitable refuge from the baking heat.

Too darned hot to survive!

Triassic fossil of an eel-like conodont. (c) Yadong Sun.

Triassic fossil of an eel-like conodont. (c) Yadong Sun.

Scientists from the University of Leeds, the China University of Geosciences and the University of Erlangen-Nurnburg (Germany) analyzed fossil records of some of the few life-forms that had survived the Permian extinction – sturdier species like snails and clams. After studying the oxygen isotopes in 15,000 conodont fossils extracted from rocks in South China, which serve as ancient seawater temperature records, the researchers found that oxygen isotopes water temperatures close to the ocean’s surface could reach 40°C.

“Global warming has long been linked to the end-Permian mass extinction, but this study is the first to show extreme temperatures kept life from restarting in equatorial latitudes for millions of years,” said Yadong Sun, lead author of a new study that documents the team’s findings.

Could it happen again?

Until now, climate modelers have assumed sea-surface temperatures cannot surpass 30°C. The modern average for the same area is between 77 and 86 degrees Fahrenheit (25 and 30 degrees Celsius).

Since 1880, global temperatures have increased by 1.4 degrees Fahrenheit (0.8 degree Celsius), two thirds of which have occurred after 1975. Despite this alarming trend, scientists assure that we’re far from witnessing a similar dire time falling upon us. Still, the pre-Permian extinction serves as a reminder of just how tough life on Earth had it, and how close it was to obliteration.

“Nobody has ever dared say that past climates attained these levels of heat. Hopefully future global warming won’t get anywhere near temperatures of 250 million years ago, but if it does we have shown that it may take millions of years to recover,” noted co-researcher Paul Wignall, from the University of Leeds.

Findings were presented in the journal Science.

Earth took 10 million years to recover from biggest extinction

Some 250 million years ago, life on Earth passed through its toughest time so far, as 96% of all marine species and over three quarters of land vertebrates went extinct. According to British researchers, the mass extinction was so severe that it took life 10 million years to recover.

With less than 10 percent of plants and animals surviving and a huge number of biological niches left unfilled, a quick bounce back could seem likely, but according to Dr Zhong-Qiang Chen, from the China University of Geosciences in Wuhan, and Professor Michael Benton from the University of Bristol, that’s not really the case; two reasons stood in the way of life: the sheer intensity of the crisis, and continuing grim conditions on Earth after the first wave of extinction.

The Permian-Triassic extinction took place at the end of the Permian period, and in those times, living on our planet was hellish: global warming, ocean acidification and ocean anoxia (lack of oxygen) all worked together to wipe out the biggest part of life on Earth.

“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,” Dr Chen said.

Current research of the conditions showed that things didn’t become pink after that – six million years after the main event conditions didn’t change significantly with repeated carbon and oxygen crises, warming and other ill effects. Some groups of animals on the sea and land did recover quickly and began to rebuild their ecosystems, but they suffered further setbacks.

“Life seemed to be getting back to normal when another crisis hit and set it back again,” Professor Benton, Professor of Vertebrate Palaeontology at the University of Bristol, said. “The carbon crises were repeated many times, and then finally conditions became normal again after five million years or so.”

However, after the environmental crisis ceased, more complex ecosystems emerged, including ancestral crabs and lobsters, as well as the first marine reptiles, paving the way for modern marine ecosystems.

“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,” Professor Benton added.

Fossil magnetism proves mass extinction theory

A scene from the late Permian

A scene from the late Permian

The mass extinction theory is… a theory, because there are still some blanks left in to fill by scientists; of course, there are those who try to fight it and find other theories and those that try to back it up and fill in the missing pieces of the puzzle. Now, the latter camp recorded a big victory, thanks to geologists from Universities of Bristol, Plymouth, and Saratov State in Russia.

They found proof in the Ural mountains (in Russia) that shows beyond the point of doubt that the world’s most severe mass extinction theorized by many researchers did in fact took place at the end of the Permian and beginning of the Triasic, about 250 million years ago (just so you can make an idea, the earliest Neanderthal appeared about 600.000 years ago)

An idea believed by many to be true was that in Russia the mass extinction did not take place and there were no fossils of species found there simply beucase of a fossil gap. Dr Graeme Taylor of the University of Plymouth explains:

“Leading authorities including the authors of the International Timescale suggested that ten million years worth of rock was missing in Russia and that the rocks present were thought to be ten million years older than they are. This would mean that the fossil disappearance in Russia would then pre-date that of everywhere else, seriously undermining the idea of a single mass extinction event.”

They used a very interesting technique that relies on calculating the magnetic record fossilised within the disputed Russian rocks and comparing it to those from the rest of the globe. By doing this, they demonstrated that the Russian rocks do record the run-up to the event.

Dr Taylor said: “There is in fact no Permian-Triassic gap. The record is complete and the mass extinction event is further strengthened as being a major turning point in the history of life on Earth and as the most catastrophic event to have, so far, affected our planet.”

How to recover from a mass extinction

saber tooth
About 250 million years ago, at the end of the Permian, and event caused a mass extinction which killed over 90 percent of the life on Earth. Ecosystems were destroyed and organisms were left to recover; it was the closest life came to being wiped out ever.

The full recovery of those ecosystems took at least 30 million years, according to new research from the University of Bristol. Previous studies indicated that life just bounced back relatively quickly in the form of ‘disaster taxa’ (opportunistic organisms that filled the empty ecospace left behind by the extinction), such as the hardy Lystrosaurus, a barrel-chested herbivorous animal, about the size of a pig.

But this latest research led by Sarda Sahney and Professor Michael Benton at the University of Bristol and recently published in Proceedings of the Royal Society B indicates that rich ecosystems with a big diversity of species emerged only after 30 million years. Sahney said:

“Our research shows that after a major ecological crisis, recovery takes a very long time. So although we have not yet witnessed anything like the level of the extinction that occurred at the end of the Permian, we should nevertheless bear in mind that ecosystems take a very long time to fully recover.”

They analyzed the recovery of tetrapods – animals with a backbone and four legs, such as amphibians and reptiles – and found that the dramatic restructurations which took place took a lot longer than initially anticipated. Professor Benton explained:

“Diversity is most commonly assessed by tallying the number of taxa on a global scale, but these studies are subject to the vagaries of sampling. By examining well-preserved and well-studied faunas, the taxonomic and ecological recovery of communities after the Permian extinction event can be examined more accurately, and the problems of geological bias are largely avoided.”