Based in Edinburgh, Scotland, THE CURIOUS PLATYPUS tells intriguing stories from the EXQUISITELY STRANGE world of biology

The five times the world ended.

The five times the world ended.

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“Biological diversity is messy. It walks, it crawls, it swims, it swoops, it buzzes. But extinction is silent, and it has no voice other than our own.” Paul Hawken

“This is the way the world ends, not with a bang but with a whimper” T. S Eliot

What constitutes the end of the world? Are explosions necessary, or fire? Does the planet have to ball up into flames and plough into the sun, or would the end of humanity suffice?

I suppose it is a matter of perspective.

The dinosaurs might be the poster children of apocalypse, but the tale of the terrible lizard is only the most recent chapter of Earth’s story. Our planet has lived five past lives. Each with its own unique cast of characters and distinct backdrop. Each with its own dramatic finale. All of Earth’s previous inhabitants must have felt that they were living through Armageddon as the slate was inevitably wiped clean for life’s next round of experimentation.

This is the story of the five mass extinctions that have ravaged our planet, the worst of which would render Earth unrecognisable for tens of millions of years. Bar one event — the meteor collision widely believed to have wiped out the dinosaurs — the source of catastrophe has always originated from our very own Mother Earth. It is perhaps these four disasters, the ‘homemade’ ones, that can teach humanity the most.

Let’s start at the beginning.

One.

444 million years ago 86% of species lost

Welcome to planet Earth, but not as you know it. We arrive at the first pit-stop on our armageddon whistle-stop tour after travelling over 400 million years into the past. This is, of course, the kind of timescale that is difficult for us hopelessly finite humans to comprehend, so to help with the mental gymnastics we will compress our planet’s 4.5 billion years into a much more digestible 12 calendar months. Even with this drastically shortened timeline, you will be waiting a while for some company: on our chosen scale, humans arrive late to the New Year’s party at 23:36 on December 31st, and the Industrial Revolution takes place with just two seconds remaining on the countdown.

A brief summary of other notable events to look out for would include: the appearance of Life Itself (albeit in a somewhat mundane single-celled form) on February 25, the unlocking of photosynthesis just in time for spring on March 21st and, in the height of summer on July 15th, the emergence of the first ever cell with a nucleus — similar to the ones which now make up you and everyone you know (as well as their dogs, cats, houseplants and sea-monkeys).

Though these developments are, of course, quite important in the grand scheme of things, aesthetically I fear they will not be much to write home about. As you wander the Earth for our metaphorical calendar year, you’ll be waiting until November 14th for even the limited visual drama of a fungus to feast your bored eyes upon. Not to worry though. If you hold out until November 25th, you might notice the seas beginning to retreat and the air getting a little chilly: we have reached our first extinction event.

At this stage, Earth probably doesn’t resemble anything that you are used to looking at. For one thing, complex life is mainly restricted to the oceans. Where it does thrive, records suggest that it probably would have consisted of a mixture of pond scum, sponges and surreal-looking Salvador Dali-esque sea creatures. The new kid on the block: the jawless fish, is causing quite the stir with its fancy backbone, the absolute height of chic in a world dominated by squishy, nondescript invertebrates. Not that there aren’t some menacing predators floating about even in this primitive landscape — villains to watch out for include the “sea scorpion”, (or the less catchy Eurypterid) which could grow to the size of a human, and the Camerocera, a strange tentacled creature that prowled the ocean in a six-metre long cone-shaped shell.

Our first global tragedy is characterised by a severe ice age. Sea levels drop as glaciers form and as you walk you will see marine dwellers left strewn across the naked shore, abandoned by the ocean. Carbon dioxide levels lower and chemical changes in the sea create a toxic environment wholly incompatible with the recent explosion of life.

Two.

375 million years ago, 75% of species lost.

Some creatures do manage to stagger through this traumatic period alive. Among them are the trilobites, a group of hardy, cockroach-like arthropods. Their spiked armour and good vision make them excellent contenders for survival, though they do take quite the hit in our next apocalypse. The jawless fish has prevailed but soon loses its pedestal, surpassed by a great radiation of more visually impressive fish which boast ownership of backbones but also jaws, as well as all manner of other superior features.

This second crisis has been linked to the arrival of the land plants, which have taken the opportunity to colonise the open ground. As they stretch out with their roots they stir up the earth and nutrients are released into the ocean. Thick tapestries of algae grow to cover the water’s surface, hungrily consuming oxygen and blocking the sunlight. Marine life languishes and suffocates in the darkened waters below.

Though some particularly plucky trilobites survived even this, you will never come across one. Like so many other unfortunate creatures, they were wiped from the face of the Earth by the third, and by far the most deadly, apocalypse.

Three

251 million years ago. 96% of species lost

Every good screen-writer knows to include an “all is lost” moment in their story. A scene where the odds seem so insurmountable, the situation so dire, that the protagonist is on the verge of giving up. We might not have been here to see it, but Earth has lived through such a time. In our story, the all-is-lost moment is a disaster so catastrophic that it has been nicknamed as “The Great Dying” by scientists. It is called the Permian extinction.

In this dark chapter of our planet’s history, life on Earth was reduced by a confounding 96 per cent and evolution was set back by 300 million years (the equivalent of almost an entire month in our 12-month planetary history).

It comes at an interesting time in our evolutionary journey. Life has exploded into glorious diversity in the ocean. Plants are well established on land and are working towards the addition of flowers to their decorative arsenal. Some time ago now, groups of inquisitive fish started to dabble in a bit of land-dwelling. Some took well to this innovative lifestyle and settled in for the long haul, growing into new, larger forms which now tread the solid earth with confidence. Evolution has spread its wings and is embracing wild experimentation. As such it is the heydey of brutish mammal-like reptiles such as the “Gorgon face” (or, more formally: Gorgonopsid), a kind of crocodile-tiger hybrid with saber teeth, and the squat, ogre-like “Two dog teeth” (Dicynodont). These are the fascinating but rather uncharismatic precursors to mammalian life.

Earth at this time might perhaps resemble a little more the planet we now call home. It is a surreal and intriguing alternate universe, brimming with possibility. Yet, by the end of the Permian extinction, it will all be gone. This thriving planet will have become a scorched hell-hole, a scarred wasteland devoid of all but the most sparse fragments of life. Molten lava will flow across the continents — still locked together in Pangaean embrace — reaching depths of more than two miles in parts of Russia. Global temperatures will surge to unbearable levels and the oceans will heat and acidify until they become noxious, stewing cesspools. Acid rain will shower the land, leaving the planet’s once lush flora in tatters. The decimation of the ozone layer will allow lethal radiation to gather in the atmosphere and kill anything which had somehow limped through this chamber of horrors. Unlike every other mass extinction so far, not even insects will escape the suffering.

Unnerved? You should be. As we have pieced together a post-mortem of our planet’s past life we have revealed a sobering truth: the Permian extinction is an example of what happens when carbon dioxide is allowed to wreak havoc on the atmosphere.

It is thought that 251 million years ago the driver of this change was continental upheaval in Siberia, a cataclysmic volcanic eruption which propelled huge amounts of C02 into the air. Today, our addiction to fossil fuels is having a similar effect. The only difference is scale: we are currently injecting carbon dioxide into the air ten times faster than the levels rose before the largest extinction event in Earth’s history.

The current environmental changes we are seeing are new to us, but they could mark the beginning of a trend that our planet has seen before. As you pass through the harrowing graveyard left by the Permian extinction take a long look around. Earth could look like this again one day in the not-so-distant future.

Four

200 million years ago, 80% of species lost

For a time, it looked like life would not prevail, as though our once-beautiful planet was destined to remain a scarred wasteland forever.

And yet, ever so slowly, Earth recovered.

Take a pause from looking at the aftermath of the Permian. Close your eyes and lift your face to the sky. If you are patient, you might feel a drop or two of water.

Finally, the rains have come, drenching the parched planet with blessed relief. With the rain, there is hope. Mother Earth exhales.

Plants will begin to creep up using the minerals left from the dead, then flowers. It will be ten million years before trees will return, but they will. Oceans will stir again with life, and amphibians will spread happily across shorelines. Once more, the air will hum with insects. Reptiles will emerge and with more confidence this time. Although they have to wait their turn, they will soon inherit the Earth.

Our fourth extinction primarily holds a message of hope, simply because it became possible.

It is brutal when it comes, again with tortured volcanic eruptions and soaring atmospheric carbon dioxide. But this time our planet has already seen worse and, after the Permian, she can survive anything

An Epilogue.

Now

If there’s anything we can learn from our planet’s troubled past, it’s that life is fragile. It exists only transiently, within a delicate balance of circumstance. If the scales are tipped, it will slip away, as naturally as a handful of dry sand. Humans may be intelligent, collaborative and inventive, but we must remember that we are not exempt from this fragility. Survival is the exception, not the rule.

For those of us in the western world, it might hard to believe that we are on the brink of a climatic apocalypse when everything feels so very normal. The morning radio show still comes on every day, the rush-hour traffic is still awful, the politicians are still bickering. There are still advertising campaigns, excel spreadsheets, reality TV shows. Surely such monotony is incompatible with the imminent arrival of the ‘end of the world’. The illusion of safety is only dispelled temporarily by poignant interruptions: the odd sensation of opening the curtains to a February heatwave, news of yet another tropical storm on the other side of the world, a particularly honest and saddening nature documentary. Such confrontations with our bleak prognosis might unnerve us, but they can always be cast from our minds as we focus on more trivial but immediate concerns.

And yet there are so many that have already been profoundly impacted by climate change. The islanders of Kiribati have watched in desperate sadness as their home of many centuries disappeared under water. Schoolchildren in the breathtaking but increasingly deadly Mekong delta are drawing flood scenes with their crayons.

It is not coming, it is already here.

So for these communities now, and for all of us later, we must do what is in our power to be more considerate tenants of Mother Earth. Like parasites, we have crawled arrogantly across her skin. We fight, we ravage, we exploit, and we forget that when we become too much of a nuisance we will simply be shrugged off. Even the rhetoric around climate action fails to remind us of this fact, that it is not our planet that needs saving, it is us. Earth has survived tragedy and she will again, but many species have perished along the way, Homo sapien could easily just be another name on this exceptionally long list.

The hallmarks of modern life, which to us might seem so eternal, could be gone as quickly as they came: no more rush-hour traffic, no more advertising campaigns, no more bickering politicians. It would take only 25000 years, a blink of an eye in planetary terms, for all traces of our presence here to be erased, bar just a few resilient plastics. The strange legacy of a species that paved its own cold road to extinction, and could do nothing but whimper when the moment finally came.

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