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Re: Hanson 2006, Mortimer, Baeker response
> > Hmm - *my* copy of "The Dinosauria" has lots of unresolved branches in
> > the cladograms - don't see that any of those is anywhere near being
> > perfect. Yes, there are no strange lineages, but if we look at a
> > cladogram comprising as many species as your probably does, the number
> > of unresolved points is huge.
> Unresolved points, by definition, raise the number of trees above "1". So,
> you speculate in error. The number of unresolved points is zero.
Now it starts to get funny: You say that it is not surprising that
your ptero cladogram is perfectly resolved and that the situation in
dinosaurs is similar. I argue that it is not and suddenly we are back
to "My cladogram is right because it produces only 1 MPT"? *You* were
the one claiming that dinosaur cladograms are well-resolved, not me.
> > Again, the argument is circular: To prove that your 1-MPT-cladogram is
> > correct and that the fossil record is complete enough, you use the
> > fact that you have a 1-MPT-cladogram.
> Remember, Martin, no one promoting any cladogram promotes that it 'proves'
> anything. So, ease off and remember we're in hypothesis land. Currently my
> cladogram solves more problems, includes more taxa and characters and answers
> more questions than any other cladogram out there. Just because you don't like
> the answers due to your prior education, doesn't mean they're not valid.
To be honest, I am not much in pterosaurs and I couldn't care less how
their tree will be resolved. I do not argue against certain cladogram,
but against what seems to me bad science, and that's were I get
> > Yes, I *hope* I am - everybody should be suspicious of a theory that
> > fits all facts perfectly.
> Wow. I didn't think you'd play that card. That tells me alot about you. So, 2
> + 2 only seems to equal 4?
No, but IMHO the evidence for 2+2=4 is slightly better than that for
all those tiny pteros.
> > Not that it is impossible, but too many
> > times in the past those all-explaining theories were just wrong.
> Too many times? Can you name two times?
I can name as many as you like: Astrology, mesmerism, shamanism,
vodoo, UFOs, ...
All these pseudosciences claim to explain it all (And most of them
claim to be scienctifically provable). So if you find a theory that
does likewise, make sure that you don't enter pseudoscience.
> > Ending with a 1-MPT cladogram does *not* prove you right, no matter
> > how nice it looks. (It does not prove you wrong, either.)
> Thank you for that. Again, proof is impossible in a cladogram. It's not the
But, surprisingly, you argue all of the time that your cladogram is
better than others because it has a better resolution (1 MPT). (See
statement above: "My cladogram solves more problems than any other" -
may be true, but does not make it right.) I'll just repeat it one
final time and then I'll rest my case: The *outcome* of a
cladogram cannot prove it valid or invalid, it is the *input* that has
to be scrutinized.
> > A cladogram in itself is, as far as I understand it, not yet a
> > hypothesis (Cladogurus on the list, please correct me). It is an
> > ordering of entities (species or specimens) based on similarity
> > criteria (character states). *If* you assume, in addition, parsimony
> > and (more important to this discussion) that all entities you put in
> > *are on the same footing* (i.e., they *only differ wrt their
> > phylogenetic position*), only *then* does it become a hypothesis on
> > phylogeny. If this additional assumption is wrong (for instance,
> > because you added entities that are not on the same footing, like
> > adults and juvies), your phylogeny will probably also be wrong.
> Thank you for inserting the word 'probably' which always allows for another
As my philosophy teacher told us (one of the few useful things I got
from there): From a wrong premise, you can conclude anything, even a
> > > Let's say that No. 9 is a juvenile. What is it a juvenile form of? Be
> > > specific
> > > and show evidence that it is indeed the candidate you propose and that it
> > > doesn't have more evidence (remember parsimony) that it is closer to my
> > > candidate.
> > And I cannot claim that the adult form has not been found because the
> > fossil record is complete? Circularity again?
> No, you're backing away from an argument. If No. 9 is a juvenile, as others
> say, it needs to be identified as a juvenile of something, even within a
> broader category or clade. So, the 'parent' of No. 9, if it exists, does not
> need to be the biological parent, but just some uncle or aunt you can point to
> that is more similar than the taxon I point to (as determined from
> phylogenetic analysis). Don't back off, if you know your pteros, give me _any_
> adult/juvenile pairing.
No, no, and no again. To prove it a juvenile, look at the bone structure.
> > But to find out whether it is a juvenile or not, you cannot look at
> > cladograms - look at the proposed juvenile's bones and check whether
> > they are fully ossified, remodeled, whether sutures have closed etc.
> I have and they're adult-like.
Wow - I did not know that anyone so far was able to section these
bones. Are they fibrolamellar? How large is the osteon density?
> But with neotony, and considering their
> absolute size, is it impossible for tiny pteros to have shorter lifespans and
> to be having sex and laying eggs prior to complete ossificiation? I'll not
> bring up humans here, because we all know that story.
Impossible is nothing (Adidas), but highly improbable. ;-)
So, they are *not* fully ossified in direct contradiction to your
statement in the previous paragraph?
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.
> > But it was *your* argument stating that these tiny pteros would fit
> > because there are tiny birds nowadays, so this is something beyond a
> > cladogram. And this argument I reject - just because nowadays (with
> > mammals and birds) niche-partitioning is done species-wise doesn't
> > mean it was so always.
> In many batches of offspring, some are larger and some are smaller than
> others. Natural selection works its wonders, sometimes in a series of size
> squeezes or size balloonings, which is exactly what I see in the cladogram. A
> series of gradual increases and decreases.
So again you use your cladogram to prove your cladogram...
Priv.-Doz. Dr. Martin BÃker
Institut fÃr Werkstoffe
Langer Kamp 8