A Disaster of Apocalyptic Proportions
A short discussion of the largest extinction and how it shaped today’s world
The Permian Mass Extinction took place at the end of the Permian period, dated to approximately 251 million years ago. I’m going to forgo being extremely precise about dates for two reasons. First, I’m talking about an event, not an appointment on a calendar, and second, no one cares.
The Permian Period was a unique time. The Earth was starting to warm. It was coming out of the cyclic glaciation that happened throughout the previous Carboniferous (which gave us our lovely coal seams in the Appalachians- but that’s for another time).
The Permian Extinction is the end-point for the period. It was so extreme that that life thereafter completely changed. It was so severe that we not only call the next time by another period name (the Triassic), but also a whole different era. The Mesozoic, meaning ‘middle life’, began and the Paleozoic ended.
So why did I choose this extinction to discuss? Well for one, this is my first big science story to throw together for you all; and I wanted to start with something big. Second, it was BIG. The largest extinction. EVER. BIG. But first, a note on extinctions.
Extinctions have happened throughout Earth’s history. As long as there has been life, there have been extinctions. Normally, extinctions are occasional events; and are balanced out by radiations, or new species appearing. These regular extinctions are called “background extinctions.”
Mass extinctions are different. Geologists currently have named five mass extinction events. Well… six, if you count the one we are currently starting, but that’s another topic for another day.
Each extinction is unique, defined by its own causes, effects, and conditions. During some, Earth got cold. During others it was dry. Some were caused by a fireball that lit up the sky (cough, cough, dinosaurs — cough). But the Permian tops them all.
So how is the Permian different?
First, this is the closest life has come to being completely wiped off the face of the planet; and no, I’m not exaggerating.
To put this in perspective: think of 100 animals. If the Permian extinction event were happening, right now, only two, maybe three of those different animals would still be around tomorrow. Now, imagine that GLOBALLY. That’s right, this event was so extreme that it’s estimated 97% of all species were killed.
Species weren’t just killed during it. Oh, no. This event came, it killed, and it stopped everything for MILLIONS of years. The devastation was so complete, so horrible, that life essentially stalled for 4–6 million years, before things finally started to pick themselves up again.
Which groups were hurt the most?
Primarily, ocean life was devastated the most. More specifically, the creatures who secrete calcium carbonate skeletons (think corals, snails, etc.). This event killed off not one, but TWO major coral groups: the horn corals and the tabulates. Many other groups, like the bryozoans, fusulinids, eurypterids (these are pretty cool- look them up), trilobites, and brachiopods either went extinct, or were so limited by this event they struggled to ever come back.
On the flip side, this event was so severe that we saw environments that hadn’t been seen in over 300 MILLION YEARS come back! The stromatolites, bacterial communities which had all but disappeared since the Cambrian, come back with a flourish. They filled in for the incredibly diverse ecosystems which had disappeared completely.
How did it happen?
So all that being said, what caused the Permian Mass Extinction?
WE DON’T KNOW! Many causes have been proposed, but none are accepted as THE cause.
What we do know is that the skeletonized organisms were devastated. We know there was an oceanic anoxic phase (little-to-no oxygen in the water), but the cause isn’t known.
We know that this extinction took place in three pulses in quick succession, in a period of under 60,000 years (that’s very fast, geologically speaking).
We know that it took 40 million years for life to even think about recovering. Furthermore, it took almost 100 MILLION YEARS for life to reach the diversity that existed before this event took place. And if you’re wondering what this new life looked like- it was the age of the Dinosaurs. That’s right; the Permian set the stage for T. rex, and his buddies, to dominate the globe!
BUT WHY???
We still don’t have a good answer. There are lots of ideas are out there, but the possible causes are hotly debated.
It’s one of the great geological mysteries; and without it, the world wouldn’t be anything like it is today.
