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Re: The Permian-Triassic Extinction
Dora Smith wrote:
I understood that the shutting down of the ocean currents only became
possible as the planets assumed their current positions, around the end of
the Cretaceous era, or later.
I was a little confused, and I thought there was some astrological allusions
here. But I guess you meant "continents" rather than "planets". :-)
The shutting down of ocean circulation causes an ice age, not global
I'm not sure if I'm responding with another non sequitur, but with the
continents jammed together to form one giant landmass (Pangaea), the
terrestrial biotas were exposed to harsher, drier environments that resulted
from a drastic decrease in the ratio of coastline to the vast interior.
A sudden drop in global temperature followed by global warming is usually
attributed to the Siberian Traps. The bolide hypothesis does not have much
support when it comes to the Permian/Triassic extinction.
The notion that that in turn causes ocean organisms to make hydrogen
sulfide is the original non sequitor. What kind of common organisms even
make that amount of hydrogen sulfide,
Lots and lots of microbes do this. I've worked with a few. Stinky.
Is there any evidence that all dinosaurs from the end of the Permian time
had modern birdlike lungs?
No Permian dinosaurs (as others have pointed out, with admirable restraint).
There were dinosaurian ancestors back then, in the form of basal
archosauromorphs (and maybe archosauriforms).
If something wiped out most life on earth tomorrow, it might be hard for
creatures 125 million years from now to believe how highly evolved life was
when that happened. There might be no primates around to tell the tale.
Just talking birds.
These talking birds might even take little mammals in cages down into their
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