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Re: What is biomechanics? (or, The Truth About Flying Snakes - Was: Re: science and philosophy)



>
>Colin McHenry wrote:
>
>> If cladistics was the be-all-and-end-all of phylogenetic
>> analysis then why hasn't there been a definitive answer to the
>> question of what animals birds evolved from.

>The fossil record is very rarely generous enough to tell us *exactly* which
>species are directly ancestral - for any group.  The best we can do is
>identify sister taxa.  On this score, cladistic analyses in recent years
>have been remarkably consistent in identifying the deinonychosaurs as the
>sister group (i.e. closest known relative)s to birds.  Any confusion on
this
>score is usually the result of efforts to "muddy the waters" - such as by
>folks who prefer purely intuitive phylogenies over rigorous analyses of
>character distribution.


Look, i'm not saying that Tim is misrepresenting me here, but I do want to
make it clear that I am not trying to muddy the waters - even though,
inevitably, I probably am because, as I've said, I don't know a great deal
about the whole dino-bird thing.

Anyway, I'm not advocating other methods of phylogenetic reconstruction over
cladistics.  I don't practice phylogenetics myself.  I have even been known
to conceed, in 'animated discussion' (hell, I even admitted it to Chris
Brochu, after he bought me a beer ;-)  that cladistics probably is the best
method of phylogenetic reconstruction available to us at this time.

The point I'm trying to make is that there may be ways to cross-check your
cladogram with other types of evidence.  If you don't want to do that, fine,
but if you don't then I reserve the right to not necessarily find your
cladogram particularly convincing.

And yes, I'm aware of the 'central dogma' of palaeontology, that we will
never find direct ancestors.  But some of the sister groups should be able
to give us an idea of what the ancestor might have looked like, and hence
how it lived, etc.   Otherwise, what use is the phylogeny?

Cheers
Colin