Why birds survived and dinosaurs went extinct after an asteroid hit earth (2020)
smithsonianmag.com
smithsonianmag.com
Does living in the ocean not provide the same benefit?
(Archer)
Why Birds Survived, and Dinosaurs Went Extinct, After an Asteroid Hit Earth - https://news.ycombinator.com/item?id=24488527 - Sept 2020 (3 comments)
A possible answer from this article (https://www.scientificamerican.com/article/how-mammals-conqu...)
The earliest Paleocene scene is dire. There is a fossil locality in Montana dated to approximately 25,000 years after the asteroid hit, called the Z-Line Quarry. It reeks of death. Almost all the mammals that flourished in the region in the Cretaceous are gone; only seven species remain. Several other fossil sites divulge what was happening over the next 100,000 to 200,000 years. If you pool together all mammals from this time, there are 23 species. Only one of these is a metatherian; these marsupial ancestors, once so abundant in the Cretaceous, were nearly extinguished. All told, if you consider the entire Montana fossil record, along with other data from across western North America, the statistics are grim. A paltry 7 percent of mammals survived the carnage. Imagine a game of asteroid roulette: a gun, with 10 chambers, nine of which hold a bullet. Even those odds of survival are slightly better than what our ancestors faced in the brave new world of the Paleocene.
This bleak state of affairs raises a question: What allowed some mammals to endure? The answer became apparent when Wilson Mantilla looked at the victims and survivors. The survivors were smaller than most of the Cretaceous mammals, and their teeth indicate they had generalist, omnivorous diets. The victims, on the other hand, were larger, with more specialized carnivorous or herbivorous diets. They were supremely adapted to the latest Cretaceous world, but when the asteroid unleashed disaster, their adaptations became hardships. The smaller generalists, in contrast, were better able to eat whatever was on offer in the postimpact chaos, and they could have more easily hunkered down to wait out the worst of the bedlam.
As ecosystems recovered in the earliest Paleocene, many of the mammals that started to multiply were eutherians, the placental antecedents that were once bit players in the Cretaceous. Their tiny bodies, flexible diets, and perhaps faster ways of growing and reproducing allowed them to commandeer open niches and start building new food webs. Around 100,000 years postasteroid a new eutherian appeared in Montana and swiftly became common. Purgatorius, with gentle molar cusps for eating fruits and highly mobile ankles for clinging and climbing in the trees, was an early member of the primate line. It, or perhaps another closely related eutherian, was our ancestor.
This happened roughly contemporaneously to the asteroid strike.
https://www.birdlife.org/news/2021/12/21/its-official-birds-...
A fact I'm reminded of when I spook a stork/heron/crane when I'm walking my dog along the river near me. They make a crazy dinosaur sound, and in flight even resemble somewhat the classic illustrations of Pterosaurs.
Bonus link, the common ancestor of both birds and crocodiles:
Do they? Or maybe we base out ideas of what dinosaurs might have sounded like on birds like these... ;)
Once we have those calls synthesized we will find out that the so called asteroid impacts were high energy experiments on the part of the Silurians. Humans will attempt the same to a similar result: lather, rinse, repeat.
But not all dinosaurs were birds, which is what the article is about.
> and in flight even resemble somewhat the classic illustrations of Pterosaurs
Pterosaurs weren't dinosaurs. Muphry's law? :)
Next to dinosaurs on the tree of life, but not dinosaurs.
Having said that, the "long necked stabby stabby from elsewhere" was a theme with the dinosaurs proper. Some have theorized that this was the hunting mode of the giant Spinosaurus.
You're right on the money with the dinosaurs=birds though though. Paleo guys even have started saying "non-avian dinosaurs" to reference the kpg "classic" dinosauromorpha, because the lineages are so intertwined. Archaeopteryx, to take one example, might not have been a bird, exactly? Birds might be even more intertwined than that, with separate bird lineages branching out at different times. The takeaway from the big extinctions is that you need to be less than fifty kilos and preferably able to dive or burrow very very deep. And be lucky, of course. Everything standing around within a few thousand miles of Cancun 65mya was probably screwed no matter how cool it was.
No worries! Someone already beat you to the punch anyways. ;)
"Hundreds of millions" is less than 30 bits of information. That's a miniscule, infinitesimal amount compared to what we're typically used to dealing with. (If you choose a random number every year, that's less that 1 gigabyte of numbers, not enough for a 30 minutes of an HD Marvel blockbuster.)
To take one example, older paleo people would see fossils of creatures like nimravids, and they'd say to themselves, "oh, a long-lost ancestor of the sabretooth cats!" - but they're not getting how long ten million years is for living systems. Sabre teeth didn't evolve once, or twice, or even three times, but evolved separately at least six completely separate instances, across 200-300 million years. This is true for all sorts of morphology that might look incredibly distinctive to our human eyes, but which aren't actually distinctive in fact.
hmmm, maybe I don't know anything
https://en.wikipedia.org/wiki/Feathered_dinosaur
https://en.wikipedia.org/wiki/List_of_non-avian_dinosaur_spe...
Found the time traveler!!
the backwards time-machine still won't have arrived
In all the world there's only 1 technology,
a rusty sword for practicing proctology
"The Smithsonian's annual budget is around $1.25 billion, with two-thirds coming from annual federal appropriations."
It makes the horrors of today less dire. Maybe sucks for "us" but not life itself. Hopefully.