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Scientists Say The Asteroid That Killed The Dinosaurs Almost Wiped Us Out Too (theweek.com)
HughPickens.com writes: Conventional wisdom states that mammalian diversity emerged from the ashes of the Cretaceous/Tertiary mass extinction event, ultimately giving rise to our own humble species. But Joshua A. Krisch writes at This Week that the asteroid that decimated the dinosaurs also wiped out roughly 93 percent of all mammalian species. "Because mammals did so well after the extinction, we have tended to assume that it didn't hit them as hard," says Nick Longrich. "However our analysis shows that the mammals were hit harder than most groups of animals, such as lizards, turtles, crocodilians, but they proved to be far more adaptable in the aftermath." Mammals survived, multiplied, and ultimately gave rise to human beings.
So what was the great secret that our possum-like ancestors knew that dinosaurs did not? One answer is that early mammals were small enough to survive on insects and dying plants, while large dinosaurs and reptiles required a vast diet of leafy greens and healthy prey that simply weren't available in the lean years, post-impact. So brontosauruses starved to death while prehistoric possums filled their far smaller and less discerning bellies. "Even if large herbivorous dinosaurs had managed to survive the initial meteor strike, they would have had nothing to eat," says Russ Graham, "because most of the earth's above-ground plant material had been destroyed." Other studies have suggested that mammals survived by burrowing underground or living near the water, where they would have been somewhat shielded from the intense heatwaves, post-impact. Studies also suggest that mammals may have been better spread-out around the globe, and so had the freedom to recover independently and evolve with greater diversity. "After this extinction event, there was an explosion of diversity, and it was driven by having different evolutionary experiments going on simultaneously in different locations," Longrich says. "This may have helped drive the recovery. With so many different species evolving in different directions in different parts of the world, evolution was more likely to stumble across new evolutionary paths."
We got off the ark?
Just before the Permian-Triassic extinction event (PT), about 250m years ago, large mammal-like reptiles (proto-mammals) were more common than lizard-like reptiles. The proto-mammals were the top of the food-chain.
But after PT, the lizard-like reptiles recovered faster, becoming the dinosaurs, and the proto-mammals were mostly small skittish creatures.
The Cretaceous-Paleogene extinction event* (CP), the one that ended the dino's about 65m years ago, was pretty much the reverse: the lizard-ish reptiles recovered slower than the mammals.
There was a short period early in the CP recovery where large dinosaur-like birds, think ostrich on steroids, seemed to have had the upper hand. (Birds are closely related to the dino's.) But, mammals eventually prevailed, as least as the largest beasts.
If Trump gets us nuked, large dino/birds/lizards may make a comeback. If the pattern continues, it's their turn again.
* Also known as Cretaceous-Tertiary extinction event
Table-ized A.I.
On the other hand, the Komodo dragon is not very closely related to the dinosaurs. It belongs with snakes, many small lizards and the ancient mosasaurs (mostly marine species) to their own group, the Squamata (scaled reptiles). It is the sister group to the archosaurs, also appearing 250 million years ago.
The whole story is quite complicated and fascinating. The KT-boundary basicly wiped out every animal that was larger than around two feet on land and three feet in the water. This was true for most of the mammals, most of the birds, all of the winged lizards, all marine lizards etc.pp.. And it took some million years for the remaining groups to recover. Birds for instance survived only on an island around Patagonia, all other ancient birds like the Hesperornithes died out.
And not all dinosaur species died out. The avian dinosaurs survived. So we have most mammal lines dying out, and most dinosaur lines dying out. In short: "giant meteor killed most, but not all, species on Earth"
Did he just go crazy and fall asleep?
>What about creatures like crocodiles, alligators, and the Komodo dragon which all could pass for dinosaurs?
Could pass for - but aren't. They are different families in the reptile kingdom entirely. Many of whom predated the dinosaurs. Even when dinosaurs were around they were not the *only* large reptilian family - they were in fact just one of four (that we know off). They were, however, the largest LANDLIVING reptiles at the time. The number two spot goes to the Pterosaurs, even though most people only know Pterodactyl who wasn't even the most impressive of that family, and which are constantly filed in with dinosaurs (in every dino movie for one) even though they were not dinosaurs (and very, very distant relatives). There were hardly any aquatic dinosaurs - the oceans then belonged to the Mosasaurs and Icthyosaurs -two families that were both just as diverse as dinosaurs. The ichthyosaurs were essentially reptilian dolphins and whales but they eventually went extinct after being outcompeted by the plesiosaurs - the third major aquatic reptile family.
And all this is still just the highlights package - I mean in the late triassic there were already turtles in the oceans - among them two whale-sized giants that could swallow a modern leatherback without chewing. Imagine a two-tonne turtle. And their descendents are also still with us.
Horse-shoe crabs are the last surviving member of a family that ruled the the oceans some 350-million years ago - long before any of these reptiles. The rise of the reptile predators probably helped along the extinction of every single species in that family - but the horse-shoes survived (and are not crabs), then outlived the great reptiles and continued right into present day - where they now hold the record as the animal that has directly saved more human lives than any other.
Unicode killed the ASCII-art *
SI units are clear, decimate is to kill 10%. centimate is kill 1 in 100, millimate is 1 in 1000. Since the SI units go up or down by factor 10, the extinction event is actually 9.3 decimates.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact