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Re: Hanson 2006, Mortimer, Baeker response
----- Original Message -----
From: "David Peters" <email@example.com>
Sent: Tuesday, June 13, 2006 1:36 PM
I note that you have not attempted to dissect my cladogram piece
Impossible without the data matrix. Let's just wait for the publication of
your paper, and then you can have all the dissection you want, if not more.
I'm not sure that you have even seen my cladogram. And if not, you are
railing against what?
Just against the principal point of believing that the number of MPTs were a
quality measure of a data matrix.
No, but IMHO the evidence for 2+2=4 is slightly better than that for
all those tiny pteros.
This is not a comparison. 2 + 2 = 4 is true by definition. That the tiny
pteros are juveniles is a hypothesis based on their similarities to
specimens which are hypothesized to be juveniles based on their bone
histology which looks the same as in extant juvenile tetrapods.
After all it falls into a well known pattern: tiny cynodonts became
Looks like it.
Tiny dinosaurs became birds.
They weren't that tiny. It's more like "tiny birds became
Tiny amphibians became reptiles.
This one, dating back to good old Romer, is wrong (at least based on the
current knowledge of the fossil record).
Michel Laurin (2004): The Evolution of Body Size, Cope's Rule[,] and the
Origin of Amniotes, Systematic Biology 53(4), 594 -- 622
Tiny archosaurs became dinosaurs.
Looks like it.
It happens all the time.
Apparently it does -- but this only means we shouldn't be surprised to find
this pattern in yet another instance. It does not mean that we should assume
to find it, let alone that we should use its presence in a cladogram as a
quality measure for a data matrix.
I'll say once again, when you repeat the word "prove" it sounds like
listening. At all costs, avoid the word "prove."
Fine, but you seem to act as if the word were all that mattered. You give
the impression of being _extremely_ confident that your cladogram is, well,
true. This is why people here keep attacking you on this point even though
you keep pointing out that your cladogram is "just" a hypothesis.
And taxon exclusion leads to
problems in cladistic analysis, as I can "demonstrate" over and over in
clades, from bat ancestry to turtle ancestry. You're trying to exclude
A specimen is not a taxon.
And as history will tell you, attitudes and prejudices color thinking.
widely accepted stoning, slavery and tail dragging were. You've simply
indoctrinated. You need to open your mind just a wee bit.
Maybe -- just maybe -- you are making the opposite mistake...? "You should
have an open mind, but not so open that your brains fall out"...
I'm saying fully ossified or not, tiny pteros can have sex with each other
Then why on the planet should they continue growing -- at baby rates --
after that? What point is there?
I guess this is the reason why we never see this happening elsewhere among
And yes, it is *very* improbable that they are nor fully
ossified. Wing bones in animals are selected for stiffness, mainly
(and toughness, next). Stiffness is governed by mineral content. An
unossified flyer would have lots of trouble with torsion and bending
in the wings - can't see how selection would not manage to ossify
earlier in individual history in this case.
And yet, some baby birds fly immediately upon hatching. And Dr. Unwin
same for pterosaurs. So your argument has been falsified.
Not in the least. All those have fully ossified wing bones and shoulder
girdles before hatching.