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Re: 11th specimen of Archaeopteryx



>> We need to learn a lesson from the BANDits; it's not enough to shoot>> down 
>> a hypothesis without proposing any alternative.>> On the other hand, there 
>> are cases where we have to admit, "We don't> know [yet]."

Exactly - These are not comparable inferences.  A functional
hypothesis (e.g. "asymmetrical feathers are connected to arboreality)
can be contradicted by a lack of other arboreal features in the same
animals.  Phylogenetic inference is based upon relative similarity, so
the only way to disparage a phylogenetic hypothesis is to demonstrate
other taxa that share more derived features (although it's worth
noting that a study which has really poor statistical support could
also be impugned as not having enough supporting data to provide any
confidence - but this doesn't apply to the current state of theropod
phylogenetics).

And finally, asymmetrical feathers are in no way directly linked to an
arboreal lifestyle.  They are simply linked to aerodynamic use -
whether gliding from some other non-arboreal location, or engaging in
some other activity (/cough, like aiding in turning).

That's not to say that there isn't a need for a lot more work on bird
origins and the selective pressures that lead to flight, but the lack
of arboreal features in the relevant taxa is strong evidence that
something other than the putative BANDit "flying squirrel" scenario
had to have played out.

-Scott

On Mon, Oct 24, 2011 at 12:54 PM, Mike Keesey <keesey@gmail.com> wrote:
> On Mon, Oct 24, 2011 at 10:51 AM, Matthew Martyniuk <martyniuk@gmail.com> 
> wrote:
>>
>> We need to learn a lesson from the BANDits; it's not enough to shoot
>> down a hypothesis without proposing any alternative.
>
> On the other hand, there are cases where we have to admit, "We don't
> know [yet]."
>
> --
> T. Michael Keesey
> http://tmkeesey.net/
>



-- 
Scott Hartman
Scientific Advisor/Technical Illustrator
(307) 921-9750
website: www.skeletaldrawing.com
blog: http://skeletaldrawing.blogspot.com/