An Imgur guide to the 1st great mass extinction...

It’s Thursday. A great day to talk about mass extinction events.

Since I usually post history posts I decided to get into the most exciting ‘history’ this planet has ever seen. The times the planet came close to wiping out all living things! There have been five of ‘em. This episode?

The 1st Great Wipe Out- the End Ordovician Mass Extinction

The boring back story:
Let’s put things on a scale here. If we assume the earth is about 4 billion years old? We will be ignoring the first 3.5 billion years of its history. I mean to be honest?
We can.

It wasn’t that exciting.

I mean SURE the late heavy bombardment was exciting if you like space rocks slamming into stuff. And yeah we SHOULD get excited about the emergence of Cyanobacteria-like filaments because yanno... life.

But really?
It’s kinda boring. I mean let’s face it, from a biological point of view, life on Earth was for most of its history?

Boring.
Eukaryotes. Multicellular algae. For over a BILLION years this was it. This was ‘life’. Goo.

(Cyanobacteria- Go goo.)

Look there are academics out there who get a real wood at pre-Edicaran fossils but to be honest?
But they are weird and no one invites them to parties. Not even the weird geek parties geologists hold.

So yeah let’s zoom along 3.4 billion years or so to where things start getting interesting...

The not as boring back story:

Events pick up 635 million years ago. Why? Sponges people! Yes, these are about as interesting as a... well, sponge but these bad boys start filtering the oceans. We have time for a brief snowball Earth period and then boom! The Ediacaran Era. Things begin to get interesting. More complex life starts appearing, and then the shit show really starts.

(Dunno what it is but I’d say- don’t fuck with it)
The Cambrian Explosion

The era where life forms become... mildly more interesting. Life is not as boring as algae but only just. Things grow in size. They get bodies and legs. BUT these life forms start changing the planet. The amount of oxygen in the oceans has increased enough to allow life begin which creates more oxygen which encourages more life- it’s a cycle baby!

And early life now starts innovating. Coming up with some wild and crazy ideas. Two of which are game changes. And they are?

Great Moments in Evolution 1: the invention of shit

Now we are talking people. Now life can recycle nutrients way faster than waiting for it to die. Get rid of excess stuff and it recycled back into the water.
When folks talk about evolution they rarely consider that for the longest time there was no shit on the planet. Like at all.

(Can we take a minute to contemplate that early anus’s and mouths were the same thing- yeah. That’s a improvement)

But that wasn’t the real game changer that helped life back then. Oh no. There was something way more formidable...

Great Moments in Evolution 2: the invention of eyes.

Things just got interesting!!!
Now life can SEE other life.

And eat it.

Mostly.

OK. Now I have the image of Mufasa giving the whole ‘great circle of life’ speech but instead of a lion I’m picturing trilobite. I need to get out more...

Anyway- so now we have a world that suddenly, properly, EXPLODES with life. Life starts appearing everywhere. (Technically I have to mention we are avoiding the Cambrian Dead Interval as like it’s an extinction level event but NOT a mass extinction level event and there is a difference). We come at last to the main feature of this tale- The Great Ordovician Biodiversification and brother? It was some wild times.

The world in the Ordovician Era

That’s us. Planet Earth. Notice the empty real estate? All that land? There is fuck all life on it. Nada. Bupkiss. OK, OK, there is SOME. Damp patches of Liverwort Type plants hug the shores. But mostly? All the action is going on in the blue.
And the oceans were teaming.

This was the era of the highest sea levels in the history of complex life. A vast, no seriously VAST, series of tropical shallow seas with a few scattered continents.

It was a fascinating place. You can make out the islands of Avalonia- today they are parts of New England, Canada, England and Wales. Back then? Sterile piles of rock lapped gently by the warm waters of the Iapetus Ocean.

These were new land masses- huge volcanic eruptions were creating a string of island mountains each roughly the size Everest.

Across the south-east there we got the continent of Gondwana (comprising parts of what would become South America, Australia, India, Africa, Arabia and Antarctica) which is drifting southwards. It’s not a supercontinent yet.

The continent of Baltica is drifting to the west, and the massive Laurentia is moving southwards. Laurentia and Gondwana use to be much bigger. The high sea levels have created these verdant shallow seas.

(So the surface kinda looked like this)

It was generally much warmer than today- CO2 levels were significantly higher, which had the side effect of making it tough for early life. Life likes it a tad cooler generally to flourish.

Any rivers around at the time? They did NOT meander. There was no plant life to hold any surface together. Rain would wash away shit real fast. Wash it away and into the sea... where it was ready to be used by the life forms.

It was in this place that life really began to grow, expand and diversify, creating a whole damn global ecosystem utterly alien to anything we know now.

Under the sea
The Ordovician Period is often called ‘the sea without fish’ and that would be right except like, there was some fish. Like the above bad boy. But anyway, on the whole? This is the era that is a Hentai lovers paradise. Way too many tentacles.

It’s an era of monsters without spines- we are talking shells, antennas and many tentacles here. Previous to now most life has been a few inches across at most. Now? Things were growing up to 20 feet long. As I said...
Monsters.
Cthulhu like creatures. Freaky ass looking things.

What like?

You had your early trilobites (gotta love trilobites- toughest little fuckers in the history of life). But in this era trilobites got scary. You had things like Isotelus Rex. Look at him. The fucking bad boy of the trilobites. 3 feet long- by trilobite standards that’s Godzilla sized. But he wasn’t the biggest baddest thing swimming around at the time.

This evil looking motherfucker is a Eurypterid. ‘Sea scorpions’. Up to 6 feet long. Imagine seeing one of them when you are scuba diving? (Technically fossil evidence suggests they were freshwater bastards so more river scorpions than sea scorpions but hey- I’m going for sensationalism here)

But the real bad boy of the Ordovician Biodiversity?
Cameroceras.

This bad boy was 20 feet long. Like... nope. Kill it with fire I say.

For 40 million glorious years this was life. This was Earth. This was Mother Nature at her most hentai. For the first 10 million years of this era? We see the biggest diversification of life in the planets history. The number of species went through the roof. And all this life was pumping out life giving oxygen which encourage MORE life...

... that looked like it fucked Cthulhu.

And then over the next 40 million years? 85% of it was wiped out.
It’s time to start the mass extinction!!!

The End Ordovician Mass Extiction (485-445 million years ago)

Now whenever folks see ‘Mass Extinction’ they get some weird ass ideas into their heads. This one? For the record- yes there were meteor strikes in this period but life carried on fine (unless it was directly below the impact site obviously).

Volcanos? Yes there were some mammoth volcanic stuff going down but it did not cause the die off. And some have even said life was wiped out via a ten second burst of gamma rays from outer space caused by an exploding supernova.

This theory i believe is proof that taking to much cocaine is bad for you.

Just saying.

The actual cause of the slow death of this teaming life filled world?

Moss.

Yeah. That’s right.
Bet you didn’t expect that.

I am Moss, destroyer of worlds

Right, I’m going to take a rather complex topic and simplify the living shit out of it. Proper experts in this field are free to wince at me and insult my parentage. Here goes...

The increased oxygen that all this life was producing got into the atmosphere. Which was cool. No seriously, it began to cool the planet. Life was dragging the temperature down.

And the biggest culprit? The creature that like Vishnu may have been the destroyer of worlds?

Moss.

The theory goes that the liverwort that use to cling to the shores of the land masses began to get its act together (evolutionary speaking) and we began to see early primitive plant life emerge on the surface. The first fungi for example. And of course that vicious genocidal monster- moss.

No, seriously, work with me here people.

The idea is that early primitive ancestors of moss realised there was much prime real estate to be had so started to spread onto the land around 470 million years ago. Here they did what plants like to do- they absorb CO2 from the atmosphere. As well as that they extract minerals from the ground they are on by secreting organic acids that dissolved the rocks below them. You know, this is what moss does right now.

But never underestimate just how brutal plant life is.

The rocks are now chemically altered and these react with the CO2 rich atmosphere and weathering of these rocks now releases way more previously locked away calcium and magnesium ions (obviously from silicate rocks), as well as releasing a shed load of iron and phosphorus. Anyway, all of this runs into the seas which acts like miracle-gro and algae gorges itself, creating massive algal blooms, resulting in organic carbon burial, extracting more carbon dioxide from the atmosphere.

It starts to get colder.

At the same time the Islands of the coast of Laurentia smashed into the mainland. This created a huge mountain range (picture a massive version of the Himalayas stretching from Alabama to Greenland? Yeah. Like that) that we call as the Appalachian Mountains today.

(Geologists, I know, I am stupidly simplifying the Taconic orogeny- I can hear you wincing. Yes it started long before this, I know. Stop it. It’s meant to be a simplification. Sorry, not sorry. The next bit is gonna actually hurt you it’s so simplified, so brace yourself).

So this region sees huge volcanic activity because two continents have ran into each other. Vast amounts of CO2 are pumped into the atmosphere. The temperature stops dropping. For a bit. But they calmed down after a few million years, CO2 levels drop again and temperature drops again.

The volcanos gave no respite.

Now the weather naturally erodes these newly exposed rocks, all that water running off these mountains is leaching out CO2. There was an additional cumulative CO2 drawn down. Which added to the temperature drop.

It wasn’t fast. We are talking the process took about 20 Million years here... but the cumulative effect was a massive Ice Age.

Huge quantities of ice now sucked up the water. Sea levels plummeted as ice began to get busy with massive glaciers emerging on Gondwana. There was as much as a 5 degree drop in the temperature of Earth.

The life in the oceans? It had no defence. It died. It died in vast numbers.

End Game
So, you get a sequence of events here.
The seas drain out, the tropics begin to cool drastically, shallow waters reduce in size, there is dangerous oxygenation of the deep, which causes a collapse of the food chain... and life gets recked!!!

Now it should be noted that due to the slow way this took place, some life did adapt. It had time. It copes. It makes it to the end of the ice age. But with the huge loss of life, the amount of oxygen drops, CO2 levels rise, the ice retreats and...?

It then gets too hot for them.
Sure not desert hot but compared to the chilly last 10 million years? The life which survived is now fucked by this AND by the fact that the warm temperatures is melting the glaciers pouring tonnes of freshwater into the saltwater oceans. This killed even more of the things in the sea. It took a good 5 million years to recover from that.

By 434 million years ago it was over. Life HAD survived. But only some. The fish made it over the Cthulhus. Added to that, the vicious world killing plant life had made it. We are now seeing little plants begin to explode onto land- ‘the lilliputian plant world’.

But mostly, many living things had died. 85% of all life was gone.

Still today, 434 million years later, the remains of these living things are still with us? We call them oil.

(OK technically I should say that the stuff the life fed on represents the first part of the formation of fossil fuels and it’s much more complex than that, but I just wanna say that the Cthulhu’s are with us every time we start our cars).

It’s all part of the great circle of life Simba.
Everything the sun touches will one day die and then be used to drive your 4x4 into your neighbours garden cos you were DUI you little shit!

Coming in the next part (cos I figure I will do one post on each mass extinction)- the Late Devonian Mass Extinctions! The Song of Fire and Ice (but mostly ice).

Notes:
Alright, where do we get the idea Moss caused the first great mass extinction?
https://www.newscientist.com/article/dn21417-first-land-plants-plunged-earth-into-ice-age/

A great wee overview of the Ordovician era from UCBerkley
https://ucmp.berkeley.edu/ordovician/ordovician.php

Hope you enjoyed. Sorry for the tone. I write these so I can get away from formal academic writing.

Most Viral Edit: awwww thank you. You guys rock. Be excellent to one another. Don’t need anything sent. Just upvote an old post.

tl;dr: life was once all hentai. And then moss killed it.