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RE: New claw paper, was RE: Early Birds Lived on the Ground



Funny you mention the brush turkey, Chris. 
I had only previously seen these birds foraging at ground level in the 
surrounds of where of i
live & work - but normally i don't pay much attention to these animals. From my 
balcony last week,
i saw (for me anyway) what was a freaky incident. I realized a large brush 
turkey, had managed to
get itself onto one of the higher branches of a tree adjacent to my balcony. At 
this point it was
some 16-18 m of the ground, about half a level higher than where i stood; how 
it got there must
have been something to see, part i missed that part (I immediately ruled out 
someone placing the
bird there). 
The next thing the brush turkey did was somehow hop amongst the branches 
building momentum before
'jump-flying' over a 8 m void to land precisely on a cable line extending from 
the building,
probably only a meter or so lower than the branches it occupied moments before. 
It then bounded of
a smaller tree, before returning to the ground. The sight left me baffled, with 
plenty of
questions and a 'what the...?' look; though, i suppose brush turkey experts may 
not find it so
exciting. 

Anyway, there's false dichotomy for you.

J

--- Chris Glen <s370548@student.uq.edu.au> wrote:

> I can happily announce that Current Biology now have the correct Supp Data
> document online (anyone that downloaded the SUPP DATA previously, trash it
> 'cause it aint quite right).
> 
> And thanks Col. 
> 
> I find there's a lot of false dichotomies that can form in discussions of
> evolutionary theory. But I can see how they are generated as a by product of
> pitting one idea against another, which is a great way of measuring them up
> and seeing which makes most sense and is most likely. This is a useful way
> of bashing out ideas, particularly when fleshing out new ones and looking
> for strengths and weaknesses. I'm sure if I had a better handle on the
> language used by philosophers of science I could frame this more exactly (at
> the risk of being  precise and clear to only philosophers of science!), but
> do hope to follow up on this discussion in future work (incidentally, hadn't
> planned to delve into the 'false dichotomy' discussion in the paper so much
> and save it for later work, but became necessary to clarify our position
> during review process, and I think the paper is much better for it). 
> 
> ...anyway, one of the pitfalls of such dichotomies is it that, without
> anyone being aware of it, the discussion starts involving arguments like 'A
> is true; therefore B is false', (and while most are busy choosing a side
> there's always a possibility of someone else saying 'Hey, no I think C is
> true, and therefore both A and B are both false!' and so on); whereas we all
> know living systems are complex with multiple states/options (adaptations,
> specialisations, behaviours etc.) that can co-exist or can even be expressed
> in the same day (e.g. that bush turkey (Megapodiid) in my back yard).
> To be sure, some states are mutually exclusive, but perhaps most are not -
> keep an eye out for them dichotomies!
> 
> Cheers,
> Chris
> 
>  
> 
> 
>  
> 
> > -----Original Message-----
> > From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] 
> > On Behalf Of Colin McHenry
> > Sent: Wednesday, 14 November 2007 11:55 AM
> > To: Dinosaur
> > Subject: Re: New claw paper, was RE: Early Birds Lived on the Ground
> > 
> > Yep, it's a good analysis and a good paper.  Well done Chris & Mike.
> > 
> > And Tim is absolutely right - the dichotomy is artificial and 
> > is not helpful.  It's the same old problem that continually 
> > dogs functional morphology - you need to get away from what 
> > you think anatomical structures are *for*, and look at what 
> > living animals *do* with them.
> > 
> > Cheers,
> > Colin  (Taking time to post on the DML 'cos I'm supposed to 
> > be doing my tax return....)
> > 
> > Tim Williams wrote:
> > > Chris Glen wrote: 
> > >
> > >   
> > >> OK, was holding off on posting a heads up to DML on the paper as 
> > >> there's the issue of the online Supp Data they've put 
> > online being an 
> > >> old draft rather than the final corrected editor's 
> > version. I've been assured this will be rectified ASAP. bit 
> > of a shame...
> > >>     
> > >
> > > I have to say I really liked this paper.  Firstly because 
> > it reinforces my pre-conceived notions about early bird 
> > evolution, and that gives me a nice warm fuzzy feeling inside.  
> > >
> > > The second reason is that it hammers home just how 
> > arbitrary and misleading the old "trees-down" vs "ground-up" 
> > dichotomy was (and still is).  Many modern birds divide their 
> > time between the trees and the ground - so why not the 
> > earliest birds and their immediate ancestors?  Unfortunately, 
> > too many hypotheses have assumed that "arboreal" and 
> > "cursorial" were mutually exclusive when it comes to the 
> > behavior of pro-avians.  'BCF' comes to mind (but then again, 
> > BCF is just plain silly).  Other ideas also fall into this 
> > trap, such as the hypothesis that pro-avians glided from tree 
> > to tree and rarely ventured onto terra firma.  This goes 
> > against the grain of the entire osteology of theropods, 
> > especially the hindlimb morphology.
> > >
> > > It'd be interesting to see how avisaurids wash up in all 
> > this, given that this is one non-neornithean Mesozoic bird 
> > group that shows anatomical evidence in support of 
> > specialized perching.  
> > >
> > > Cheers
> > >
> > > Tim
> > >
> > > _________________________________________________________________
> > > Boo! Scare away worms, viruses and so much more! Try 
> > Windows Live OneCare!
> > > 
> > http://onecare.live.com/standard/en-us/purchase/trial.aspx?s_cid=wl_ho
> > > tmailnews
> > >
> > >
> > >   
> > 
> > 
> > --
> > Colin McHenry
> > Computation Biomechanics Research Group 
> > http://www.compbiomech.com/ School of Engineering (Mech Eng) 
> > University of Newcastle NSW 2308
> > 
> > t: +61 2 4921 8879
> > 
> > 
> > 
> 
> 



      
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