Seeing as I'm a direct descendent of the pioneers who wiped out the Neanderthal, the dire wolf, the giant cave lion, and giant cave bear, I'm perversely proud of that. (Although I'm sure my ancestors would look at me, an above-average 21st century physical specimen, as a chicken-boned wimp with a tiny brain. Not very big. Not very strong. Not very clever.)
Point being, I've really to wonder about intelligence as a long-term survival trait. And the theme today is, has it happened before?
All those mass extinction events in the fossil record, all due to "natural' causes?
The late Ordovician, life still bound to the sea, and 50% of it wiped out. Mostly trilobites and invertebrates, but some primitive jawless fishes, and straight-shelled cephalopods in shallow tropical waters, with the vast Panthalassic Ocean spread over the entire Northern Hemisphere. Did the continent of Gondwana park itself at the South Pole, causing catastrophic glaciation, lowering the sea level and eliminating whole swathes of habitable shallow? Or did some intelligent cephalopods get too smart for their own good? Very difficult to develop any kind of technological civilization under water, but then, I'm thinking like a plains ape, with fire and smelted metals and dry sticks and stones ready to hand. Why not build tools out of modified life? Who says you can't create a bacterium to generate electricity, radio waves, nuclear fission? Not me. It could have happened.
The late Devonian, another 50% wipeout, and again primarily marine. Animals still stuck in the ocean, save for early tetrapods, but land plants have developed to create their special form of havoc. Did a clever relative of Ancanthostega manage to screw the pooch (anachronistically speaking) upon landfall? Or did the tentacled ones manage a second chance, only to blow it?
The Big One. The End Permian. 250 million years ago. 96% of all marine species. 70% of all land vertebrates. Was it a comet? A continental United States sized volcanic eruption now known as the Siberian Traps? Super global warming from the coal deposits burned by said eruptions? Temperature extremes from the forming of the supercontinent Pangaea? Revenge of the hydrogen sulfide excreting purple bacteria? A combination of all of the above? Or was it one of the mammal's ancestors, a therapsid with a too much brain and not enough sense? One over time able to manipulate rocks into rockets, and thence to tip them with nuclear barbs? Would there even be a fossil record for that?
The end Triassic. Kind of disappointing as extinctions go, but still a respectable 48% death rate. it is thought to be due to the some two million cubic kilometers of magma released during the Central Atlantic breakup, along with two quadrillion kilograms of sulfur di- and trioxide molecules. But then again, it might have been an early dinosaur with a big brain.
The Cretaceous. Well, everyone knows it was Comet Chicxulub, right? The "tail of the devil" went smacko, whacko, slapping right into the ocean north of the Yucatan with an explosive force of 100 million megatons of TNT. Or could it have been some feathered serpents? Some smart version of Quetzalcoatl mucking up the timeline with a fissile slugfest with some other mythical power? And throw in a little peyote to get the whole Mexican flavored apocalyptic vision quest to going?
Which brings us full circle to the present. Or did I leave out the Oxygen Crisis of 2.5 billion years ago? Well, those of us In The Know, know it was the Spirochete Conspiracy. Yeah, Penrose's (if you buy into Penrose, which I don't, but never deny a source of entertainment) quantum-minded microtubules, not quite entirely tamed into eukaryotes yet.