Holy Shit, Mass Extinction!

Mass extinction is, you might (very correctly) assume, a pretty bad thing. I mean, every mass extinction so far has paved the way for a new form of dominant life on Earth, so there are some silver linings. We're here because of mass extinction.

But still, an event where over 50% of the species on Earth have been wiped out can only be called a catastrophe. This has happened on at least five occasions on the geologic time scale. The worst of them was the Permian-Triassic Event over 250 million years ago.

This chart is the visual equivalent of jargon, but the Event in question is the highest blue peak.

In that event, up to 96% of the species on Earth were completely eliminated. While there are several theories as to the cause of this disaster, it's nearly impossible to tell for certain what happened. Maybe a large meteor struck the planet or a supervolcano erupted and kicked up enough dust to choke out the majority of life. Maybe a massive, cross-species plague swept through every living thing. Maybe the atmosphere simply changed and most life couldn't catch up.

The point is, shit died. A lot. And that was just the worst Mass Extinction Event. There have been several others. The most famous was the one that finished off the dinosaurs.

It's not like they were even phoning it in by the end. T-Rex was one of the last surviving species

The criteria for a mass extinction is that roughly half the species on the planet must have been destroyed within a short period of time. A short period of time on a geologic scale, mind you, means "within a million years or so."

Or, "Significantly longer than the entirety of human history

So when I tell you that Earth has lost 50 percent of its wildlife in the past forty-five freaking years, you should know that this means serious business. We are absolutely in the middle of a mass extinction. Right now. And we are absolutely the cause. Whatever your feelings are about the environment, there is no way that this will end up being anything but terrible for humans.

Because "mass extinction" really is just as terrifying as it sounds.

Holy shit.

Holy Shit, the Oxygen Catastrophe

Let's say your an obligate anaerobic organism, and it's roughly two and a half billion years ago. You're hanging out on Earth, and you've pretty much got the whole place on a string. The world is your oyster (except those don't exist yet, so the world is your...I don't know, other, smaller type of obligate anaerobe).

One day, a new guy shows up. Or several million new guys, because they're bacteria and they come in large groups. These new guys, the cyanobacteria, are pretty different. They go through this whole process of photosynthesis and end up producing oxygen, and it's kind of weird. You're not a fan. In fact, the stuff is toxic to you.

More like toxygen, amirite? Guys? Hehe. Classic.

Luckily for you, dissolved iron and organic matter ends up capturing most of the oxygen, so you continue on your merry way for another 200 million years or so. At that point, the oxygen sinks become fully saturated. That means oxygen starts becoming a part of the atmosphere. For you and all your friends, that's a bad thing. A very, very bad thing.

The "anaerobic" part of "obligate anaerobic" means "without air/oxygen." The "obligate" part means oxygen will straight murder you. Which is exactly what happened. The same event that started Earth's atmosphere down the path toward being breathable also caused one of the largest mass extinctions of all time. It was essentially an apocalypse. The only survivors were the culprits -- who passed on the trait of photosynthesis to future generations -- and a few varieties of anaerobic bacteria that could tolerate the new atmosphere.

Oxygen was basically the Cthluhu of the obligate anaerobic world.

To get an idea of just how big the Oxygen Catastrophe was (and yes, that is an official name for it), just imagine the same thing happening today. Instead of oxygen, imagine it's an element that humans can't breathe. One that might cause dangerous fluctuations in the living conditions on Earth for the majority of its species. Something like, I don't know, carbon dioxide.

Oh, wait...

Well this isn't totally comforting.

Holy shit.