Re: flying Archie

[don ohmes <d_ohmes@yahoo.com>]

Tim wrote-- 

1. "However, there are probably many reasons why the modern 
avian body plan "took over" - associated with the ability to fly long 
distances, to better maneuver in flight, to catch prey on the wing, etc.  
But _Archaeopteryx_ may not have needed any of these things."

2. "In terms of numbers of species, passerine birds outnumber all other kinds 
of birds 

combined; but I wouldn't say that passerines are "superior" to ratites or 

penguins or birds of prey.

Don writes--

1. The terms 'inferior' and 'superior' relative to quantifiable 
traits/processes are useful and necessary. If you can fly faster, further, and 
"dodgier" than I, you are a _superior_ flyer. Whether I _need_ to fly is moot. 
But if I _do_ need to fly, I'm in big trouble, right?

2. Maybe not morally superior. Relative to speciation, passerines are 
definitely superior to ratites or penguins or birds of prey.

Don


----- Original Message ----
From: Tim Williams <twilliams_alpha@hotmail.com>
To: dinosaur@usc.edu
Sent: Saturday, September 23, 2006 8:21:32 PM
Subject: Re: flying Archie

T. Michael Keesey wrote:

>If it wasn't "inferior", then why did the modern style take over?  You 
>could argue that it was linked to something else that provided a 
>significant advantage, but in the absence of any such explanation it seems 
>simplest to assume that the modern style is "superior" (i.e.,
>confers significant reproductive advantage).

I take your point.  However, I think it's a case of apples and oranges.  
_Archaeopteryx_'s style of flight was (presumably) very different to that of 
modern birds.  I don't know why or how it flew, and we'll probably never 
know for sure.  However, there are probably many reasons why the modern 
avian body plan "took over" - associated with the ability to fly long 
distances, to better maneuver in flight, to catch prey on the wing, etc.  
But _Archaeopteryx_ may not have needed any of these things.  Its style of 
flight was suitable for its limited purposes.  Each to his own, I guess is 
what I'm saying.

The other reason why I avoid terms like "inferior" and "superior" when 
discussing evolution is that it implies progress.  I know what you're 
getting at when you use these terms; but they do have baggage.  In terms of 
numbers of species, passerine birds outnumber all other kinds of birds 
combined; but I wouldn't say that passerines are "superior" to ratites or 
penguins or birds of prey.

>(Of course, Archie's style must have been "superior" to that of its 
>predecessors.)

Again, this is apples and oranges (or oranges and pomegranates).  Anyway, 
Archie's style may not even be "superior" to its predecessors.  For example, 
the microraptorans may exemplify one of the pre-_Archaeoptyeryx_ stages in 
the evolution of flight.  Although microraptoran taxonomy may currently be 
oversplit, microraptoran species are rather common in the Jehol biota.  
There may have been microraptoran-style gliders everwhere in the Early 
Cretaceous, and they may have outnumbered _Archaeopteryx_-style fliers.

Cheers

Tim