Extinction question /sci/?

>>8731579
>monkeys and birds
They didn't exist back then you git.

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>small organisms with lower caloric demands better able to withstand ecosystem collapse than large resource-intensive organisms
>I just don't get it

of course, mass extinctions are a lot more complicated than that, but that's the primer. remember, it wasn't the meteoroid that killed all those things; it was the collapse of the global food web caused by the scorching of much of the globe and the ensuing impact winter killing off a lot of plant life.

>>8731579
>monkeys and birds
>dinosaurs didn't?
>and birds
>dinosaurs didn't
>birds

>>8731579
Is it actually confirmed that it was a meteor that caused that extinction? I always thought that was just a meme. Like an actual real meme, using the correct definition of meme.

>>8731840
Are you memeing now?

>>8731579
>>8731711
>>8731840


Meteorite is confirmed. Google the KT boundary. We've found and mapped the (fucking huge) crater. The layer of irridium found world-wide corresponds to the time of the dinosaur's extinction, as does the dating of the samples from the crater. In addition, the layer of irridium also contains extremely large numbers of indicators of shock metamorphism, which only occurs during meteorite strikes and nuclear explosions.

The layer also contains a very high density of micro-spherules, which are formed as vaporized rock condenses and falls back to the Earth.

Interesting thing: From the varying thickness and density of the layer, you can calculate how quickly it must have been laid down. The vast majority was laid down within the day of the impact. This correlates to several kilos of material falling on every square meter of the planet. Such a mass re-entering the atmosphere following the ejecta plume would have been sufficient to bathe the surface of the Earth in thermal radiation, literally cooking anything alive that didn't have shelter; i.e, anything that didn't live underground, under water, or couldn't burrow or find similar shelter.

tl;dr
> asteroid is not a meme
> asteroid confirmed
> turned the surface of the earth into a pizza oven

- t. physics + planetary science major.

The metorite theory is a fairytale. The truth is that dinos died becouse climate cooling. Only warm blooded land animals survived.

>>8731925
It doesn't explain why we survived. So it's not a valid theory.

>>8731822
Birds are warm blooded.

>>8731925
just did some digging. this dude appears to be correct. good on you anon

>>8731969
small mammals were largely thought to occupy small, sheltered areas and burrows, and would then be easily capable of surviving the brief (not more than a few hours long) period of thermal irradiation.

>>8731969
in addition, it wouldn't make it an invalid theory. The evidence conclusively indicates a meteorite strike at that time. If there is no clear way mammals could have survived, then that indicates a lack of knowledge on our part, rather than that the meteorite strike is invalid.

You can't argue with shock metamorphism.

>>8732041
you can if you're retarded :^)

>>8731975
And are also dinosaurs

>>8731969
>we

>>8731579
Flying dinos became birds. Velociraptors had feathers though did not fly.

>>8732278
Velociraptors became fucking ostriches

>>8731579
smaller size and lived underground

I heard during a lecture that the meteorite caused a shockwave in the magma that caused volcanoes to erupt on the opposite side of the globe. They said the lava floes in India date to this period.

>>8732391
Its bullshit. Extensive studies have shown that meteorite impacts aren't linked to increases in volcanism.

there's approximately one study linking meteorite impacts to increases in output of the Deccan Traps of India, but the study is on very shaky ground and is approached by many in the field with a great deal of skepticism (keep in mind that the Deccan Traps had several periods of eruption, and the one study connecting them to meteoritic impact suggests that it increased output to some degree, rather than triggering it itself. )

I guess this thread can also be "Ask about anything related to Impacts", if anybody would like. I should be working but need a distraction.

>>8732433
>>8732391
the study:
http://gsabulletin.gsapubs.org/content/127/11-12/1507.short

I might honestly be overly-critical about it.

>>8731840
Yes. It landed in the Gulf of Mexico. Not only did it convert the atmosphere into a giant oven, but it threw up a bunch of debris to cause a nuclear winter for a few years. Small mammals (and maybe birds) that were burrowed underground were able to survive the barbecue. Experiments have shown that only a small layer of soil would be sufficient to provide adequate shelter from the estimated atmospheric temperature.

>>8731925
It was a comet not an asteroid you brainlet.

Iridium and osmium levels, as well as mineral content at the impact site confirm it.

>>8731925
>Meteorite is confirmed.
hello brainlet.

>>8732496
souce?

From my own understanding, the energy of the impact and its metallic composition had actually been arguments against a comet.

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It's not about surviving the impact. The asteroid, which was about 6 miles across, would have sent up a lot of debris into the atmosphere, similarly to a large volcanic eruption.

The resulting climate change was survivable for mammals, who were small and adaptable, but not so much for dinosaurs who were larger and tended to live in warm climates.

>>8732557
>image
Oh, how disappointing, I thought the entire gulf was the crater.

>>8732568
>I thought the entire gulf was the crater
we wouldn't be here if that was the case

>>8731840
It is confirmed that there was an impact of a large object, and that non-bird dinosaur fossils(and a number of other critters) are not found above the layer of debris and dust associated with the impact.

This makes it look a lot like the impact caused the extinction, and this is, last time I looked, the consensus view.

There are some contraindications, including fact that many dinosaurs seem to die out well in advance of the impact (which might reflect reality, or might be an artifact of spotty fossil record) and the fact that there were other impacts, including during the "age of dinosaurs) that do not seem to have associated mass extinctions.

Personally, I suspect something else was stressing the shit out of the ecosystem and reducing biodiversity when the KT impact delivered the final, decisive strike that led to the mass extinction we see.

>>8732433
Whether or not the Deccan Traps were caused by the impact (seems really unlikely) they could nonetheless constitute the one-two punch that created the spectacular mass extinction which other impacts, or other periods of volcanism, don't seem to have always created.

>>8732557
Dinos seem to have lived pretty much everywhere.

>>8732238
We, the survivors.

>>8732041
Your argument is that a big rock from outer sky killed all the dinos, but not mammals?

>>8732557
This might be the true answer

>>8731969
Why is a board about science filled with so many idiots?

>>8732727
The survivors were tiny, burrowing rodents. This has been mentioned multiple times in the thread. There were no primates around at the time.

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>>8731925
>gulf of mexico

so thats not just a product of continental dirft

the entire gulf is the fucking crater?

>>8731579
Wat about crocodile and a shark

>>8733299
No
See >>8732557