[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: 11th specimen of Archaeopteryx



This boils down to "well, there may be some other explanation other
than arboreality we don't know about yet." That may be true. But are
there any studies that propose what that may be? Off the top of my
head I recall that wings have been proposed as functioning in
maneuverability during fast running. Do asymmetrical remiges aid this?
Any studies on the topic? Have any alternate functions of feather
asymmetry ever been proposed and researched? If not, how does this
refute the arboreality hypothesis? We already know that modern birds
use such feathers to get into high places and/or fly, and it's
unlikely Archie was doing the later.

We need to learn a lesson from the BANDits; it's not enough to shoot
down a hypothesis without proposing any alternative. If too much is
made of feather asymmetry, it's only because few people have proposed
or been able to support any alternate hypotheses.

Matt

On Mon, Oct 24, 2011 at 1:39 PM, Habib, Michael <MHabib@chatham.edu> wrote:
> Personally, I think that too much is made of the asymmetrical remiges, in 
> general.  Some considerations in that regard:
>
> 1) Asymmetrical vanes may be functionally advantages in ways other than lift 
> production
> 2) Asymmetrical vanes are not required for effective flight (despite claims 
> in the literature to the contrary)
> 3) Symmetrical vanes may not have been the developmentally ancestral 
> condition for contour feathers.  Granted, they probably are, given the fossil 
> record of feather evolution, but there is still the possibility of secondary 
> flight loss in the mix that makes it difficult to confidently claim that the 
> first true "contour" remiges were symmetrical.  Secondarily flightless birds 
> do not necessarily "mirror" incipient flight evolution.
> 4) Even if we assume that asymmetrical vanes evolved under selection for 
> mass-efficient generation of fluid forces, there are plenty of ways to use 
> such forces other than weight support.  WAIR is just one of them.  The other 
> potential advantages do not all involve getting into high places.
>
> --Mike
>
>
> On Oct 24, 2011, at 1:20 PM, Matthew Martyniuk wrote:
>> What about the asymmetrical remiges? If Archie and/or its ancestors
>> were not at the very least using WAIR (to get up into high places,
>> presumably), why did they evolve? Symmetrical remiges are just as good
>> as asymmetrical for brooding nests, display, or any other alternate
>> uses of the wings that have been proposed.
>>
>> Matt
>
> Michael Habib
> Assistant Professor of Biology
> Chatham University
> Woodland Road, Pittsburgh PA  15232
> Buhl Hall, Room 226A
> mhabib@chatham.edu
> (443) 280-0181
>
>