What's Wrong With This Picture?
hesp...@clark.net
DID AN ASTEROID PRECIPITATE DINOSAUR EXTINCTIONS?
We are told that 65 million years ago, Earth was a lush tropical paradise
populated by ferns, dinosaurs, reptiles, insects, fish, a few small mammals,
and other interesting prehistoric stuff.
Suddenly WOOOOSH, an asteroid slams into the Gulf of Mexico, and Earth is
condemned to a 5000 year long night. As a result the dinosaurs and most
other animal species are wiped out.
At first hearing that scenario sounds pretty convincing. I certainly
bought it, but the more I think about it the farther fetched it seems to me.
Two things really bug me about the hypothesis.
1. We are told that birds evolved from dinosaurs.
In fact IMHO, they *are* dinosaurs.
How does that fit in with the dinosaur extinctions?
2. The crocodile.
The crocodile is a large creature, and needs to consume a lot
of meat. (If you doubt that, check out a croc's teeth sometime.)
The crocodile lived on Earth before the age of dinosaurs, and it
*still* lives on Earth. How did it survive the 5000 year night?
Perhaps crocodile and other reptilian eggs can survive freezing?
Is that a possibility (and is there a paper in there somewhere? :-)?
Still, what about the birds? You sure can't get viable chickens e.g.,
from frozen eggs!
#%^>
Bright Blessings,
Hesperos, AAAS
*-------*-------*
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* "No one has a right to say: this is right, or that is *
* wrong. It isn't just one way." --- Gloria M. Estefan *
*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*
Mary
hesp...@clark.net () wrote:
> DID AN ASTEROID PRECIPITATE DINOSAUR EXTINCTIONS?
>
>We are told that 65 million years ago, Earth was a lush tropical paradise
>populated by ferns, dinosaurs, reptiles, insects, fish, a few small mammals,
>and other interesting prehistoric stuff.
>
>Suddenly WOOOOSH, an asteroid slams into the Gulf of Mexico, and Earth is
>condemned to a 5000 year long night. As a result the dinosaurs and most
>other animal species are wiped out.
>
>At first hearing that scenario sounds pretty convincing. I certainly
>bought it, but the more I think about it the farther fetched it seems to me.
>
>Two things really bug me about the hypothesis.
>
> 1. We are told that birds evolved from dinosaurs.
> In fact IMHO, they *are* dinosaurs.
> How does that fit in with the dinosaur extinctions?
>
Not all dinosaurs die at once?
> 2. The crocodile.
> The crocodile is a large creature, and needs to consume a lot
> of meat. (If you doubt that, check out a croc's teeth sometime.)
> The crocodile lived on Earth before the age of dinosaurs, and it
> *still* lives on Earth. How did it survive the 5000 year night?
>
Their food chain was not effected in the same way as the dinosaurs?
Mary
PTWahl
On 1 Dec 1997 15:47:15 -0500, hesp...@clark.net ()
wrote:
> DID AN ASTEROID PRECIPITATE DINOSAUR EXTINCTIONS?
>
>We are told that 65 million years ago, Earth was a lush tropical paradise
>populated by ferns, dinosaurs, reptiles, insects, fish, a few small mammals,
>and other interesting prehistoric stuff.
>
>Suddenly WOOOOSH, an asteroid slams into the Gulf of Mexico, and Earth is
>condemned to a 5000 year long night. As a result the dinosaurs and most
>other animal species are wiped out.
>
>At first hearing that scenario sounds pretty convincing. I certainly
>bought it, but the more I think about it the farther fetched it seems to me.
>
>Two things really bug me about the hypothesis.
>
> 1. We are told that birds evolved from dinosaurs.
> In fact IMHO, they *are* dinosaurs.
> How does that fit in with the dinosaur extinctions?
>
> 2. The crocodile.
> The crocodile is a large creature, and needs to consume a lot
> of meat. (If you doubt that, check out a croc's teeth sometime.)
> The crocodile lived on Earth before the age of dinosaurs, and it
> *still* lives on Earth. How did it survive the 5000 year night?
>
>Perhaps crocodile and other reptilian eggs can survive freezing?
>Is that a possibility (and is there a paper in there somewhere? :-)?
>Still, what about the birds? You sure can't get viable chickens e.g.,
>from frozen eggs!
>
>#%^>
>
>Bright Blessings,
>
>Hesperos, AAAS
Among other things, there was a *major* volcanic event
about the same time as the asteroid. (Roughly southwest
of India, if I recall, and more or less antipodal to the site
of the Yucatan crater. If the dates work out, the asteroid
may have caused this "contra coup" event.)
The lava flow must have had climatic effects and may well
have helped end the Mesozoic. Whether triggered by the
asteroid impact or just a coincidence, it does complicate the
simple picture of "big rock, boom, all fall down."
I don't know about the "5000 year night." It seems that
5000 years would suffice for evolution to remove fragile,
useless structures like eyes, or at least leave us all as blind
as the salamanders that live in caves. Maybe it was more
like one or two years, followed by centuries of twilight. In
the volcanic picture, this might have included good years
among the bad ones.
I don't know if reptile eggs survive a hard freeze. But warm
springs, stoked by geothermal energy rather than solar,
might have kept the crocs alive. Crocs can eat fish, and so
the question becomes, what did the fish eat? Perhaps the
whole ecology was based on thermophilic bacteria, instead
of photosynthesis.
I think birds and dinosaurs began their split long before
these catastrophes. At least, birds were a "different kind"
of dinosaur from the thunder lizards. But you do pose a
good question.
Why would bird-type dinos survive, yet all the other small
dinos vanish? And if some small dinos survived, why did
they not rise again to dominate the world? The basic design
was successful for such a long period. If something like a
bear can evolve into a blue whale, I am puzzled why the
reptiles never regained their super sizes in any niche of the
ecosytem. (Except maybe "Nessie"?) And why have no
birds reverted to the ways of lizards? (Though, there was
some sort of huge, terrible bird creature on Madagascar --
wiped out not too long ago, I recall.)
One plausible speculation (beyond the reach of proof) is
that these catastrophes helped select a new kind of disease.
Clearly all the beasts were stressed, likely immune-
compromised as well. In such circumstances, bugs (like
our "black plague") are known to turn nasty. Perhaps the
genes for "really big reptile" are expressed alongside
susceptibility to this germ. If the germ is endemic but
benign in smaller lizards, it may exist today. Hence, the
"dinosaur mutation" is universally fatal.
The nicest part of armchair "science" is freedom from
tedious things like experiment and proof. I offer none.
(And can't explain why this dread disease waited for the
asteroid to fall. Was it exobiotic stuff, say from Mars? Or
was the asteroid's fall a mere coincidence, hundreds of
years after the great extinction?)
But I agree that the present explanation of this extinction
remains incomplete. Clearly a large enough asteroid can
end all life on Earth. Yet if only some species disappeared,
it is good to ask, why those died and "our kind" lived on. If
a little irritant like humanity is wiping out the coral reefs,
how did they survive the hammer that fell on Yucatan?
Patrick
Tom Deering
> DID AN ASTEROID PRECIPITATE DINOSAUR EXTINCTIONS?
>
> We are told that 65 million years ago, Earth was a lush tropical paradise
> populated by ferns, dinosaurs, reptiles, insects, fish, a few small mammals,
> and other interesting prehistoric stuff.
>
> Suddenly WOOOOSH, an asteroid slams into the Gulf of Mexico, and Earth is
> condemned to a 5000 year long night. As a result the dinosaurs and most
> other animal species are wiped out.
>
> At first hearing that scenario sounds pretty convincing. I certainly
> bought it, but the more I think about it the farther fetched it seems to me.
>
> Two things really bug me about the hypothesis.
>
> 1. We are told that birds evolved from dinosaurs.
> In fact IMHO, they *are* dinosaurs.
> How does that fit in with the dinosaur extinctions?
>
> 2. The crocodile.
> The crocodile is a large creature, and needs to consume a lot
> of meat. (If you doubt that, check out a croc's teeth sometime.)
> The crocodile lived on Earth before the age of dinosaurs, and it
> *still* lives on Earth. How did it survive the 5000 year night?
>
> Perhaps crocodile and other reptilian eggs can survive freezing?
> Is that a possibility (and is there a paper in there somewhere? :-)?
> Still, what about the birds? You sure can't get viable chickens e.g.,
> from frozen eggs!
Perhaps the changes in climate were much more subtle than that. It's not
hard to imagine that some species would be able to withstand changes in
climate better than others.
If that's true, then species better able to adapt would survive, and
species that could not cope would perish. That seems to fit the scenario
just fine.
Concerning your two points, I believe that
1. Birds and dinosaurs had common ancestors. There are other dinosaur
relatives still alive. Why pick on birds?
2. There are other large creatures that predate the dinosaurs that still
roam the planet. Why single out crocodiles?
While there may be problems with the asteroid theory, the points you make
don't seem to be among them.
Tom
hesp...@clark.net
Tom Deering (no.spam.@please.thx) wrote:
: In article <65v7oj$i...@commedia.cnds.jhu.edu>, hesp...@clark.net () wrote:
: > Still, what about the birds? You sure can't get viable chickens e.g.,
: > from frozen eggs!
:
: Perhaps the changes in climate were much more subtle than that. It's not
: hard to imagine that some species would be able to withstand changes in
: climate better than others.
:
: If that's true, then species better able to adapt would survive, and
: species that could not cope would perish. That seems to fit the scenario
: just fine.
We are also hashing this out on the M e-mail list, and your remarks,
though perhaps a bit obvious, do seem to pertain.
#%^>
: Concerning your two points, I believe that
:
: 1. Birds and dinosaurs had common ancestors. There are other dinosaur
: relatives still alive. Why pick on birds?
Because birds are descended directly from dinosaurs.
(IMHO, they *are* dinosaurs.)
That can not be said of any other species alive today.
: 2. There are other large creatures that predate the dinosaurs that still
: roam the planet. Why single out crocodiles?
Crocs are a good example, IMHO.
They are large (larger than many dinosaurs AAMOF), require a lot of food,
and have teeth which are designed to devour other large creatures.
: While there may be problems with the asteroid theory, the points you make
: don't seem to be among them.
I don't agree.
Richard Thompson
PTWahl wrote:
>
> On 1 Dec 1997 15:47:15 -0500, hesp...@clark.net ()
> wrote:
>
> > DID AN ASTEROID PRECIPITATE DINOSAUR EXTINCTIONS?
> >
> >We are told that 65 million years ago, Earth was a lush tropical paradise
> >populated by ferns, dinosaurs, reptiles, insects, fish, a few small mammals,
> >and other interesting prehistoric stuff.
> >
> >Suddenly WOOOOSH, an asteroid slams into the Gulf of Mexico, and Earth is
> >condemned to a 5000 year long night. As a result the dinosaurs and most
> >other animal species are wiped out.
> >
> >At first hearing that scenario sounds pretty convincing. I certainly
> >bought it, but the more I think about it the farther fetched it seems to me.
> >
> >Two things really bug me about the hypothesis.
> >
> > 1. We are told that birds evolved from dinosaurs.
> > In fact IMHO, they *are* dinosaurs.
> > How does that fit in with the dinosaur extinctions?
> >
> > 2. The crocodile.
> > The crocodile is a large creature, and needs to consume a lot
> > of meat. (If you doubt that, check out a croc's teeth sometime.)
> > The crocodile lived on Earth before the age of dinosaurs, and it
> > *still* lives on Earth. How did it survive the 5000 year night?
> >
> >Perhaps crocodile and other reptilian eggs can survive freezing?
> >Is that a possibility (and is there a paper in there somewhere? :-)?
> >from frozen eggs!
> >
decline now, they’ve led an uninterrupted existence predating that of
the dinosaurs. What afforded these, seemingly, fragile creatures the
wherewithal to withstand a cataclysmic change?
Richard