Last post, I mentioned something called the Permian-Triassic mass extinction. I figured I’d clarify a bit.
If someone were to ask you to name a mass extinction, which would you name? Likely as not, it’d be the death of the dinosaurs, officially known as the K-T Event (T is for Tertiary, the first mammal-dominated period. K is for Cretaceous. In case you’re wondering, there are three periods that start with C, and the Carboniferous got its letter first. The Cambrian has a weird thing that looks like an euro sign with only one bar). You might name the current mass extinction, the Anthropocene Extinction (Anthropocene just means” Age of Man”). But neither comes close to being the worst mass extinction in Earth’s history.
At the end of the Permian period, something happened. Nobody knows what for sure, but it happened, and it was catastrophic. It was the Great Dying, and life has never come so close to vanishing altogether.
It has been suggested that there were actually several “pulses”of extinction. The first was likely due to gradual climate change. The last could have been due to a meteorite impact, massive volcanism, sudden and drastic climate change, huge coal or gas fires in what is now Siberia, drastically increased aridity, or… well, there’s no consensus at all, really.
What is known for sure is that the whatever-it-was’ effects on life were devastating. On land, ~70% of all vertebrates died out. In the seas, the overall death tall was closer to 96% of all living things. Even the insects suffered. To put this in perspective, this was the only time a mass extinction ever affected the insects. If you were to only look at the numbers of insects and their growth or decline, you would never notice the K-T Event ever happened. But not even they went through the Great Dying unscathed.
The therapsids, which ruled the land, nearly went extinct, never to recover. Many—most—of the remaining giant reptiles and amphibians vanished. The last of the trilobites and sea scorpions, both of which predated the first vertebrates to have jaws, disappeared.
Obviously, not *everything* died. Some species made it through, mostly thanks to sheer dumb luck. Enough scarred, limping and traumatized individuals survived, close enough to each other and to food for their species to endure. They bred, laid their eggs, and fed and raised their young. They spread and diversified, filling all the empty niches. Some evolved into the first mammals. A group of small running reptiles, the thecodonts, gave rise to the dinosaurs.
Life went on. It always does, in the end.
But the path of life on Earth was forever altered.