[HN Gopher] The asteroid that wiped out dinosaurs didn't impact ...
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The asteroid that wiped out dinosaurs didn't impact bird evolution:
new study
Author : gardenfelder
Score : 21 points
Date : 2024-02-20 20:57 UTC (2 hours ago)
(HTM) web link (www.nytimes.com)
(TXT) w3m dump (www.nytimes.com)
| gardenfelder wrote:
| https://archive.ph/StNCT
| yodon wrote:
| >"The signal from the fossil record is not ambiguous," Dr. Berv
| said
|
| The fossil record says the asteroid had a big impact on bird
| evolution. A fancy new computer model trained on DNA data says it
| didn't. The computer model's results are surprising and not
| supported by the fossil record.
|
| I know where I'm placing my bets.
| TSiege wrote:
| The fossil record could be incomplete, and both could be true.
| I've seen other studies hinting at bird evolution happened
| older than we thought
| yodon wrote:
| The fossil record is certainly incomplete, but it's also
| certainly more reliable than a new DNA model reporting
| conclusions that make no sense (the impact didn't impact bird
| evolution? There's no way that passes the smell test)
| kjkjadksj wrote:
| Just because there was genetic diversity before the asteroid does
| not mean it did not affect things. A human builds a shack in the
| woods and that has measurable impact in terms of ecosystem
| disturbance decades even centuries after its a ruin. An asteroid
| is going to do something.
| TSiege wrote:
| This is a very strange argument. I don't see how you can say the
| asteroid had no impact. There were entirely new niches that
| opened up after the mass extinction. Birds by definition had to
| evolve into them after the impact since ~75% of species went
| extinct. I can believe that birds evolved before the impact, but
| to say it didn't impact bird evolution is like saying mammal
| evolution wasn't impacted by the impact because mammals pre-
| existed before then. Who knows if birds would be as dominant as
| they are today had the impact never have happened.
|
| Today there are almost twice as many species of birds as there
| are mammals. I think both can easily be true
|
| > When searching for fossils of the major groups of birds alive
| today, scientists have found almost none that formed before the
| asteroid hit. That striking absence has led to a theory that the
| mass extinctions cleared the evolutionary arena for birds,
| allowing them to explode into many new forms. But the new study
| came to a very different conclusion. "We found that this
| catastrophe didn't have impact on modern birds," said Shaoyuan
| Wu, an evolutionary biologist at Jiangsu Normal University in
| Xuzhou, China.
| bluGill wrote:
| Scientists find lots of fossils in places where they are likely
| to form, which is mostly wetlands. We have much less evidence
| for what the rest of the world was like just because those area
| didn't leave evidence behind. It may be that birds and mammals
| dominated the earth - except for wetlands where dinosaurs lived
| (probably not, but we don't have much evidence)
| nemo wrote:
| This computational model doesn't match the fossil record which
| suggests the flaw is in the model, not the evidence.
| greazy wrote:
| They used the fossil record to fine tune the baysian
| phylogenetic model. So no this is not correct.
| riazrizvi wrote:
| So looking at the timeline of DNA diversification in birds, the
| biggest spread occurred 10's millions of years before the
| asteroid mass extinction, and net there was not so much after the
| asteroid hit itself. Makes sense to me as I imagine birds were
| hit with devastated ecosystems and had to adapt, though I imagine
| their greater range made them more resilient.
| zozbot234 wrote:
| Birds, seriously? "Birds" are not real, they literally _are_
| dinosaurs.
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