In the early 1800’s, Baron George Cuvier (the father of Paleontology) popularized the now mostly forgotten theory of Catastrophism.
Before then, Cuvier had already established himself as one of the greatest minds of his day. He is the one responsible for every giant fossil skeleton you’ve ever seen. After years of carefully studying the anatomy of modern and extinct animals, he realized that all vertebrates share both a common body form and similarly functioning anatomical parts.
His breakthroughs are what allows us even today to recreate full specimens of any vertebrate using only a handful of fossils. In fact, nearly all ancient skeletons found in museums are not complete skeletons at all.
When we stand next to that giant T-Rex, we might only be standing next to 4 actual bones – and each from a different T-Rex!
That’s not to say that these grand skeletons are works of imagination though. Cuvier proved that functional relationships exist between different anatomical structures, and by understanding those relationships we can reconstruct just about anything.
For example, it would be ridiculous to assume that because we didn’t find a right arm at the fossil site that we must have discovered a whole new one-armed species of T-Rex. We know it had a right arm that mirrored its left one (or at least was born with one). That may seem obvious to us now, but this was a big idea at the time, and Cuvier was able to prove it through a lifetime of comparative anatomy and paleontology.
But one question always dogged him – why does the anatomy change over time in the first place?
He noticed that the older the fossils, the more disconnected they were from modern species. His colleague Jean-Baptiste Lamarck (a MindGiant in his own right), proposed a nascent theory of evolution nearly 50 years before Darwin, but Cuvier wasn’t buying it. He objected not on religious grounds, but on scientific ones.
Here was his logic:
If each species is perfect for its environment at the time, any change to it would make it imperfect, and thus kill it before it was able to evolve. But if the environment suddenly changed, the animal would no longer be perfect for it, so how could it survive long enough to change at all?
To answer this riddle of nature, Cuvier adopted and refined with scientific evidence a theory known as Catastrophism. He first proved that different extinct species in different geographic areas had not perished all at once, but periodically throughout history and typically following sudden regional catastrophes. He believed that each catastrophe simply wiped out the “old” and gave rise to the “new and improved” species.
This idea met with little resistance from religious scientists of the day, who had long held the biblical flood responsible for all extinct species simultaneously. (Note that deep sea fossils were still a long ways off.)
While Cuvier himself stuck to scientific reasoning, his theory was quickly married to the notion that these catastrophes and improvements were executed directly by God. God had not only flooded the whole planet in the early days, but He was also responsible for periodic local catastrophes that caused only certain species to go extinct and new versions to rise in their place.
The idea was palatable enough for nearly everyone. God was still directly choosing what survived based on His personal preference and the scientific evidence that these catastrophes befell various parts of Earth routinely after the flood was no longer ignored.
It was logical, scientific, had plenty of fossil evidence to support it, and easily explained how an entire species could go extinct after the Great Flood.
Of course, the works of later figures like Darwin and Wallace would eventually spell the end of catastrophism, but some of its core tenants and questions were hugely influential to Darwin himself and some remain unanswered to this day.
There are indeed many examples of seemingly overnight evolutions in response to sudden environmental changes and no clear evolutionary mechanisms to explain them. Natural Selection is just one of the mechanisms we know of, but that is a long, slow process with many limitations. Genetic drift and spontaneous mutation are also not as punctuated as the fossil record requires.
Since Cuvier’s day, explanations for these examples have ranged from still undiscovered evolutionary mechanisms to extra-terrestrial intervention. (The latter of which would of course be awesome.)
What we do know is that along with all of the life on Earth, our scientific theories themselves continue to evolve. Though many of our theories undergo a slow, gradual refinement based on carefully accumulated data, every now and then someone proposes a new theory that to the accepted notions are, well… catastrophic.