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Re: OCCAM'S RAZOR & THERIZINOSAURS
A listmember kindly pointed some potentially confusing aspects of
this last post. While I was tempted to ignore this unfortunate message and
move on, that little shred of ego we attach to everything we write urges me
to clarify rather than wholly abandon. I wrote:
> A) I didn't buy this "morphospace" analogy before, [...]
> C) Flying-flightless is a simple step [...]
> G) As you yourself pointed out earlier, [...]
There seems to be some misunderstanding on these three points, both
on my part and on others'. These points were not intended specifically as an
attack on the point that the transition from flying to secondary
flightlessness in theropods was less diffficult than the transition from
initial flightlessness to flightedness [gasp... ok, caught my breath]. My
point was that the "morphospace" model is simplistic and impractical for
dealing with issues such as this, a point I had made earlier. Further, The
use of that model in this instance is strongly inconsistant with previous
uses of the model in support of arguments on therizinosaur evolution.
Apparently, I took too much liberty at the invocation of the
morphospace model, by assuming that in a one-dimensional morphospace it
would be as great an "evolutionary distance" forward as backward. Hence my
confusion as to why this model was used to support an easy reversal to
As to the question at hand, many birds are equipped with a locomoter
module which in many groups is already quite suited for terrestrial
locomotion. Most (if not all) birds seem to spend an appreciable part of
their lives on the ground or otherwise using that locomotor module. We might
even suggest that these facts might have applied even more to earlier birds.
In either case, it seems eminantly logical that reversal to flightlessness
is not an unlikely evolutionary event.
So, although I disagree with the model used to make the point, I
believe it is safe to agree with the point George was originally trying to
make, that a reversal to flightlessness among theropods (and I'm only
willing to say this for theropods right now) seems likely to have occurred
many times and is not an unresonable hypothesis in and of itself (as anyone
who has been molested by an emu on an Danish TV commericial can tell you).
>and deliberate misunderstandings of concepts
Please strike this statement from the record without further comment.
>BCF Olshevsky style has very little merit as a scientific theory
And this as well.
Jonathan R. Wagner, Dept. of Geosciences, TTU, Lubbock, TX 79409-1053
"...To fight legends." - Kosh Naranek