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What Caused the Dinosaur Extinction?

theatlantic.com

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Re: What Caused the Dinosaur Extinction?

#11

Post by pfdietz »

lkrubner wrote: post #10

Start with a 3 species model. Imagine a shallow, closed sea, in which there is a shark, a plesiosaur, and a bird. We need to explain why the shark and the bird survive, but the plesiosaur goes extinct. An asteroid hits somewhere, causing environmental change. For the rest of this comment, I'm going to refer to temperature as a short-hand way of referring to any environmental change. The shallow, closed sea is undergo…

Yeah, no. There was massive extinction of single cell creatures (forams, for example) and also plants, which don't have immune systems.

A good match for the extinction patterns is which species could survive a prolonged interruption of photosynthesis.

Re: What Caused the Dinosaur Extinction?

#12

Post by frozenport »

lkrubner wrote: post #10

Start with a 3 species model. Imagine a shallow, closed sea, in which there is a shark, a plesiosaur, and a bird. We need to explain why the shark and the bird survive, but the plesiosaur goes extinct. An asteroid hits somewhere, causing environmental change. For the rest of this comment, I'm going to refer to temperature as a short-hand way of referring to any environmental change. The shallow, closed sea is undergo…

The animals you mentioned have active, as well as learned immunity. The systems in vertebrates are quite similiar. I'm not sure what your point is.

Re: What Caused the Dinosaur Extinction?

#13

Post by wild_preference »

lkrubner wrote: post #10

Start with a 3 species model. Imagine a shallow, closed sea, in which there is a shark, a plesiosaur, and a bird. We need to explain why the shark and the bird survive, but the plesiosaur goes extinct. An asteroid hits somewhere, causing environmental change. For the rest of this comment, I'm going to refer to temperature as a short-hand way of referring to any environmental change. The shallow, closed sea is undergo…

What’s with all the pretentious exposition? You could’ve shared your shower-thought in 140 chars.

Re: What Caused the Dinosaur Extinction?

#14

Post by vertline2 »

pfdietz wrote: post #4

The evidence for a massive impact precisely at the K/T boundary is ironclad. Any alternate theory in which the impact was not causal has to explain how this incredible coincidence (the largest impact in the past 100 million years occurring in a layer deposited in just thousands of years, right at the boundary) occurred.

Is it possible for a meteor to cause a chain of volcanoes to blow? like all the pressure under the crust gets rattled around?

Re: What Caused the Dinosaur Extinction?

#15

Post by dang »

wild_preference wrote: post #13
lkrubner wrote: post #10

Start with a 3 species model. Imagine a shallow, closed sea, in which there is a shark, a plesiosaur, and a bird. We need to explain why the shark and the bird survive, but the plesiosaur goes extinct. An asteroid hits somewhere, causing environmental change. For the rest of this comment, I'm going to refer to temperature as a short-hand way of referring to any environmental change. The shallow, closed sea is undergo…

What’s with all the pretentious exposition? You could’ve shared your shower-thought in 140 chars.

Please don't be nasty here.

https://news.ycombinator.com/newsguidelines.html

Re: What Caused the Dinosaur Extinction?

#16

Post by ian0 »

pfdietz wrote: post #4

The evidence for a massive impact precisely at the K/T boundary is ironclad. Any alternate theory in which the impact was not causal has to explain how this incredible coincidence (the largest impact in the past 100 million years occurring in a layer deposited in just thousands of years, right at the boundary) occurred.

This struck me as precisely the type of thing that they were giving out about in the article. So I asked a geologist was there more to it. They said:

The Cretaceous-Paleocene event is dated to 66m years ago [1]. The crater has been dated to 65m years ago [2]. The deccan traps was from 63-69m years ago with the bulk of activity 66m years ago [3].

Obviously both the volcano and the meteor were life-changing events. Of the three events the fossil record analysis is the hardest to analyse. But there are indications that the volcanos main activity may have preceded the meteor and that while the meteor did obviously contribute may not have been the main cause of the extinction. IE the dinosaurs may have been on their way out before it, or it may have been a "combination" of the two.

[1] https://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_e...

[2] https://www.ncbi.nlm.nih.gov/pubmed/17789640

[3] https://link.springer.com/article/10.1007%2FBF02981139

Re: What Caused the Dinosaur Extinction?

#18

Post by dmoy »

vertline2 wrote: post #14
pfdietz wrote: post #4

The evidence for a massive impact precisely at the K/T boundary is ironclad. Any alternate theory in which the impact was not causal has to explain how this incredible coincidence (the largest impact in the past 100 million years occurring in a layer deposited in just thousands of years, right at the boundary) occurred.

Is it possible for a meteor to cause a chain of volcanoes to blow? like all the pressure under the crust gets rattled around?

Seems like yes?

https://www.whitecoatinvestor.com/expense-ratios/

Re: What Caused the Dinosaur Extinction?

#19

Post by jhbadger »

dannylandau wrote: post #2

Extremely well written and fascinating story on a competing theory for the mass extinction. still not convinced that the generally accepted Alavarez Asteroid hypothesis is wrong. Worth a read nonetheless.

That's the thing in pop science though. String theory is generally accepted -- so write about the iconoclasts who reject it. Asteroid accepted as the end of dinosaurs? Write about the iconoclasts there.

Re: What Caused the Dinosaur Extinction?

#20

Post by pfdietz »

jhbadger wrote: post #19
dannylandau wrote: post #2

Extremely well written and fascinating story on a competing theory for the mass extinction. still not convinced that the generally accepted Alavarez Asteroid hypothesis is wrong. Worth a read nonetheless.

That's the thing in pop science though. String theory is generally accepted -- so write about the iconoclasts who reject it. Asteroid accepted as the end of dinosaurs? Write about the iconoclasts there.

String theory is not generally accepted. It has not made a single successful prediction, or indeed any predictions at all. It's more correct to say most physicists view it with skepticism mixed with disdain.
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