Say a brontosaurus or T-Rex or similar dinosaur was magically transported to the current day. Would our atmosphere kill them?
Was there more oxygen in the atmosphere 65 million years ago, or am I thinking of an earlier era? In any case, most creatures can survive at altitude, where there is much less oxygen available. At 3600M above sea level you are only getting 2/3 of the oxygen, and people live at that altitude. Carbon dioxide levels have probably changed, but this shouldn’t be significant. A dinosaur should be able to breathe our atmosphere without problems.
Don’t know if they’d be able to cope with modern microbes though.
no need for continued speculation. I used my time-machine to transport one of these creatures to the current era and it survived. was only a two minute test though.
There’s some evidence that there was less Oxygen in the atmosphere (as little as 12%), but there’s also some evidence that atmospheric pressure was a lot higher - as much as 28psi. So it might be swings and roundabouts in the breathing department.
IANA expert in this … In mammals at least, breathing regulation is driven by CO2 concentration in the blood. Climbing to altitude results in less oxygen, but also less CO2. The net effect is your breathing process is undisturbed. Less effective overall, but not whacked out.
IF the atmopheric composition now is a bunch different from back then, I’d expect the animal’s breathing control system to malfunction. Maybe enough to kill them. Or maybe only enough that they’d be fine until they tried to run, and then they’d pass out.
Bottom line: I’d expect any reasonable atmospheric pressure difference between then and now to be no big deal, but any atmospheric composition difference to have a significant impact.
I freely admit that I often get my era’s mixed up but wasn’t there a much greater concentration of atmospheric oxygen at some point? This is what allowed the insects to achieve such large sizes. Given the higher concentrations of oxygen their respiration systems weren’t as limited as they are currently. The higher amounts of oxygen coming from greater density of plant life.
The era you’re thinking of is the Carboniferous, I think.
The key point there is carbon dioxide concentration in the blood, the carbon dioxide is produced by metabolic processes. Doubling the amount of CO2 in the atmosphere won’t have a corresponding affect on blood chemisty.
Humans can certainly tolerate a wide range of atmospheric conditions. The Apollo astronauts breathed 100% oxygen (although at reduced pressure) for 2 weeks.
Did they? I know that Apollo 8 had a 100% oxygen atmosphere, but ISTR that after the fire on the launch pad, they changed the atmosphere for to something a bit closer to normal air.
Yes, during the Carboniferous period the oxygen concentration was around 1/3 of the atmosphere (today it’s about 20%). It’s the reason giant invertebrates like dragonflies with three-foot wingspans and meter-long scorpions were able to grow so large. The way oxygen is diffused in invertebrates puts an upper limit on their size, and if you could transport one of these animals to modern times they likely wouldn’t be able to survive in today’s atmosphere.
Although lower for much of the Mesozoic, oxygen levels spiked in the late Cretaceous. Some online sources say up to 32-35%. Here’s a graph:
edit: on the graph, the late Cretaceous/end of the dinosaurs period (65 million years ago) should be about 35% of the way from the “100 million years ago” mark to today – right where the curve peaks.
Modern impact hypotheses generally mention worldwide firestorms caused by impact heat and by masses of superheated material falling back through the atmosphere around the world, and made more intense by the higher oxygen concentration.
They did for launch, but the in-flight atmosphere was 100% oxygen. See Wikipedia: http://en.wikipedia.org/wiki/Apollo_1#Remains_of_CM-012
I just wanted to point out that there is no such thing as a ‘brontosaurus’. I’m pretty sure the OP meant a Apatosaurus (probably spelled that wrong), or maybe one of the other sauropida.
As to the actual question, no idea.
-XT
And there’s also no such thing as a “dog”; people using that word probably mean Canis familiaris.
However, ‘dog’ has not been superseded by a more precise term. ‘Brontosaurus’ has been, even if it’s still in popular use.
In any case, since I had a friend of mine who specializes in this sort of thing bust my chops about it, I thought I’d share. Disregard, since it really doesn’t have much bearing on the actual question.
-XT
Well their is since everyone knows what you are talking about. The first Apatosaurus they found was so incomplete that when they found a full one of the same species and a lot bigger they thought it was different and named it Brontosaurs, Apatosaurus is correct since it was named first, they just had a young one. We have different names for young/old animals now.
The problem wouldn’t be the air. The problem would be modern viruses.
Is this right? I was under the impression that haemoglobin in the blood would bind more readily with CO2 than it would with Oxygen, so higher levels of CO2 in the atmosphere would reduce the oxygen in the blood. Isn’t this why space shuttles have CO2 scrubbers in them to keep the CO2 levels down? I thought if you had an ‘air’ mix of say 80% Oxygen and 20% CO2 it would be unbreathable as the haemoglobin would ignore the Oxygen (essentially).
His chop-busting was inappropriate, if he does, indeed, specialize in such things. Brontosaurus is still very much attached to Apatosaurus - they are different names for the same creature, with the latter having priority (and thus being the “official” name in scientific circles). There is nothing more or less “precise” about one name vs the other. It is absolutely false, however, that “there is no such thing as a ‘brontosaurus’”.
And really, if you’re going to bust chops over “brontosaurus”, you should also bust chops over “T-Rex”, since that’s wrong, too - it should properly be T. rex.