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Birds Had To Relearn Flight After Meteor Wiped Out Dinosaurs, Fossil Records Suggest (theguardian.com)
An anonymous reader quotes a report from The Guardian: Birds had to rediscover flight after the meteor strike that killed off the dinosaurs, scientists say. The cataclysm 66 million years ago not only wiped out Tyrannosaurus rex and ground-dwelling dinosaur species, but also flying birds, a detailed survey of the fossil record suggests. As forests burned around the world, the only birds to survive were flightless emu-like species that lived on the ground. The six to nine-mile-wide meteor struck the Earth off the coast of Mexico, releasing a million times more energy than the largest atomic bomb. Hot debris raining from the sky is thought to have triggered global wildfires immediately after the impact. It took hundreds or even thousands of years for the world's forests of palms and pines to recover. Fossil records from New Zealand, Japan, Europe and North America, all show evidence of mass deforestation. They also reveal that birds surviving the end of the Cretaceous period had long sturdy legs made for living on the ground. They resembled emus and kiwis, said the researchers whose findings are reported in the journal Current Biology.
Never understood how birds are the only remaining dinosaurs... wonder what made dinos so vulnerable to this event, where many other large species (crocs, turtles, fish, etc) survive to this day. One might think that some small dinosaurs, or aquatic/marine species would have found a niche on some continent. Population bottleneck, I guess. Imagine if no dinosaurs at all had survived... maybe we'd have a lot more large insects and bats species filling the skies.
It's interesting that flightless birds had a pretty strong reign during the early recovery phases. They were often the dominant hunters of the time.
It's often speculated that mammals eventually replaced those giant flightless birds as the alpha hunters not because mammals are more powerful than big birds, but rather because mammals learned to better leverage pack hunting: social coordination. Otherwise, this era would have resembled Dinosaurs 2.0, with 40-foot birds: Sqaaawwwk!! BOOOM
Table-ized A.I.
Not suprising as it is also thought to have created a tsunami 330 feet tall along the coasts of Texas and flordia, but as high as 2.9 miles in deep ocean. It is 12 miles deep and 93 miles in diameter. It's pretty amazing as you can date the effects in many areas by the layer of material it spread over the whole world. Good thing these giant impacts are extremely rare because if we spot it late there is jack squat we could do.
Considering how the flight of the hummingbird more resembles that of an insect than it does of other birds.
I am very very likely completely wrong, but I would speculate birds - flying birds - survived, and rapidly lost their power of flight, because it was no longer needed, because their predators were all dead.
They had to learn how to fall.
#DeleteChrome
Both the article and the summary but not the actual paper make the claim that the only birds to survive were flightless. The actual paper talks about the demise of arboreal species. This makes sense as it is difficult for a tree-dwelling species to survive if the trees have gone. It does not follow that the survivors were necessarily flightless. Today most ground-dwelling species retain the ability to fly. And many of these have long, sturdy legs. Given that these kinds of birds don't tend to fly much, it is reasonable that many of these would adapt to a purely flightless lifestyle in the absence of predation. It does not follow that birds had to learn to fly all over again. Even if it took hundreds to thousands of years for the forests to recover, there should still be populations that retain flight ability allowing them to radiate back into the trees quickly.
They didn't learn too well..
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nuttin
Flightless birds never evolved a way to really repurpose their front limbs. Ostriches, emus, kiwis all have vestigal wings with limited use if any. Other land vertebrates, whose front limbs hadn't become so highly specialized yet, could gradually evolve them along different paths to become good tree climbers (everything from chameleons to monkeys), or learn to dig burrows (moles), to be good swimmers (OK, penguins also managed to make good use of their front limbs in that regard, but I'm not sure if the ancestors of penguins were flightless.) have claws for helping to hold onto prey while killing it, and so on.
In theory, theory and practice are the same; in practice they're different. (Yogi Berra & A. Einstein)
"hundreds or thousands" of years to recover? what does recover mean? it takes forests decades to recover if that. it would take hundreds or thousands of years only for forests to recover to the exact state they were in when the fire occurred but that's a pretty nonsensical definition because some forests would _never_ recover. words, the cause of and cure to so much misunderstanding.
"Consensus" in science is _always_ a political construct.