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Re: "But What About The..." arguments (long!)
----- Original Message -----
From: "David Elliott" <firstname.lastname@example.org>
> >The problem here is, IMNSHO, that you try to explain the extinction of
> >dinosaurs. Yeah, right. :-) Why did the ammonites die out? The rudists
> >the inoceramids? Heaps of foraminifera and haptophytes[...]?
> I'm not sure that's a valid counter-argument: it assumes that the original
> poster is claiming that their idea explains the extinction of mosasaurs,
> rudists, etc etc - as far as i recall he only claimed to be explaining the
> extinction of the dinosaurs.
True, thanks for that reminder, but...
> Sure it may wall be a good assumption that they're linked, but it's an
> assumption nonetheless - wouldn't the proper counter-argument be to argue
> that they're linked, so you can *then* say "what about the foraminifera
> so forth", or "your theory doesn't account for the link"?
Yes. And I do think that when there's that huge impact, there should be a
huge catastrophic mass extinction. Such a mass extinction is present. So it
should IMNSHO be the null hypothesis that everything that dies out then does
so because of the impact, and the burden of proof is on those that want to
take something out of this picture, as HP John Bois apparently tries to. I
think this can work on the background extinction level -- with some species,
not with large clades. That something as big & diverse as Dinosauria died
totally out with the feeble exception of Neornithes due to background
extinction is definitely unlikely. That it does so right at the time when a
huge impact-induced mass extinction takes place requires very convincing
evidence that I don't see.
> But even then, in science don't we usually figure out small parts of
> before we put them into a larger framework? Don't we often see parts of
> puzzle before we see the larger picture?
That's indeed how things tend to work, but it's not a part of the scientific
method. I see it that way that once a larger picture emerges scientists try
to explain the special cases from this generality -- deduction,
respectively, that they try to shoehorn all new evidence into it until it
tears apart under the load. Then it's considered falsified by those that
can't imagine how to fix it. :-) (Has been called the hypothetico-deductive
process IIRC -- a hypothesis is built, and then people try to explain
everything from that hypothesis via deduction.)
> Regarding Robert Bakker, he DID actually talk about the extinction of all
> those other critters (in TDH), [...] - that was one part
> intrinsically tied in with a larger model. [...] (pages 440-444 The
Just read it again. That larger picture is nothing more than regression,
_suddenly_ opening Beringia for land travel, without _any_ word about how
this affected dinos in Madagascar, India and Africa, or ammonites, or
forams... In the last paragraph, he allowed for an impact as coup de grâce,
> Say for a moment that Bakker didn't have a larger model worked out to
> explain everything else's extinction. Even then, the "what about the..."
> argument wouldn't apply as a counter-argument. It would be a call for some
> larger integrated model, or for some argument about wether or not the
> dinosaurs extinction *is* related to the foraminifera etc etc extinctions,
> but i don't think it invalidates the virus-idea in any way.
Biogeography does, though. Also, the Great American Interchange wasn't
nearly as catastrophic as Bakker wrote on said pages.
> To a vaguely related topic that i just thought i'd raise while i was
> how strongly linked are the extinctions of mosasaurs, foraminifera,
> plesiosaurs, etc etc..?
> Have statistical studies been done into the probability of 'everyday'
> of extinctions occurring, by chance, during other larger extinctions to
> create the impression that they're related when they're not (and how sure
> are we of timing, btw?
That way you'd ask very much of background extinction.
> [...] we can't always tell *exactly* when something dissappeared)?
For things like nannoplankton and pollen we can do that pretty well. For
things like ammonites a few decades of sampling have made look their
extinctions more and more catastrophic, indicating that the gradual pattern
observed first was caused by the famous Signor-Lipps effect; the last known
ammonite is now within the last 10 cm below the boundary and several cm in
diameter itself. For things like dinosaurs... well, the last known nonavian
dino track is 37 cm below the boundary, and not one is above it.
> Im just thinking, if stegosaurs had happened to delay their
> extinction until the end of the Cretaceous, we'd assume they were part of
> mass extinction that they might not have been.
On the other hand, if stegosaurs had happened to survive whatever did them
in, the K-T impact would certainly have finished them off, don't you think?
> Are mosasaurs, for example,
> such a large and diverse group (i don't get the impression that they are)
> that their extinction is statistically something drastically different
> the extinction of a group like the stegosaurs?
Yes. And what's more, they are much, much richer in preserved individuals,
and had a global distribution.
> How regular are extinctions of groups of sizes comparable to the various
> components of the K-T extinction?
To me it looks like that never happens... but I know far too little about
the internal taxonomy of, say, trilobites, conodonts, ammonites, corals,
echinoderms etc. etc., and for terrestrial groups the fossil record is
usually the limiting factor -- I've lamented several times about how that
Asian clade of basal Eutheria is known from the Coniacian and the Campanian
or early Maastrichtian, not at all from the Cenozoic, and apparently there's
no known good K-T or late Maastrichtian site in general anywhere in Asia, so
said furballs can have died out anytime in the Maastrichtian. :.-( (Of
course I think it's most parsimonious to assume the K-T impact got them.)
> i'm really just asking, how sure are we that EVERYTHING that died out at
> that time is a part of the one big thing?
Why shouldn't it be? The burden of proof is on those that think not
everything is a part of it. :-)
> Is it possible that, say 5-15% (just pulling a figure out of my sleeve for
> the sake of argument, theres no meaning in those numbers) of some mass
> extinctions are just coincidence - actually, isn't it almost *certain*?
Not, I think, when the mass extinction involves, say, 75 % of all species
> And if it didn't, if some groups might've gone for
> unrelated reasons, then an argument like the virus-argument - i.e. about
> extinction of one *particular* group - is quite perfectly valid and
> expected, and the "What about the foraminifera etc..." argument has an
> point against it.)
One more thing... how would one _test_ the disease hypothesis? Finding the
virus or bacterium is pretty much out of the question because it won't
preserve anyway, finding fossils that show evidence of disease is unlikely
because most diseases don't affect the bones... how would you do it?
Why do you think Dinosauria in its entirety, except for Neornithes,
is "one particular group" for that purpose? I mean, not even all placentals
can get rabies... and there have been AIDS-resistant humans (though very
few) for years. Rinderpest is dangerous for ruminants, but not for whole
species of them AFAIK.
Is there actually any documented case of a disease causing the
extinction of a _species_?
> Anyone know of some good papers/work having been done around this issue?
> seems like the kind of thing there'd be heaps written about, [...]
Probably... but not in the kind of journals I've read so far. :-)