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Re: Velociraptor profiles and a little background



I pondered:
<My own feeling, for what it's worth:  some active, warm-blooded 
animals
who were flexible in hunting strategies developed feather precursors 
as a mutation and it persisted because it kept them warm.  All 
other behaviors were affected by having feathers; they adapted 
to feathers and feathers to the adaptations.
Call it feathers came first.>
And you responded:
<Exactly as I wrote: you start out with a fully feathered, fully 
winged
coelurosaur.>
Well, I didn't say anything about winged.  Wings reduced arm/hand 
capabilities so much that I have to think some progress toward 
moving through the air was made before full wings would add more 
than they lost.
A number of birds, not all, that concentrate on swimming lose 
much of their wings, so swimming's not the first thing I think 
of as encouraging wing development.

When I observed that 'feathered' animals could, and maybe did, 
try a lot of different strategies, you commented:
<"Possible [they tried different strategies]" or "yes"? If "yes", 
you are arguing for a pretty extreme generalist... might be improbable.>
Thinking of isolated populations.  A group of animals in one 
location may find a particular strategy most effective, another 
group a different one. The different selective pressures would 
eventually produce different species.  (And very similar new 
species would be generated if the same strategy were used in 
widely separated locations.)  Hence, the different strategies 
being tried would lead to different speculations if someone were 
expecting only a single answer.  I'm suggesting multiple correct 
answers for the lifestyle of feathered, pre-bird animals.  Only 
one or a few of these groups ever flew.
I'd settle for a conclusion of 'Not unreasonable.'




 


= = = Original message = = =

> <You get something like a dipper, sort of; *Archaeopteryx* 
is IMHO an
> example of such an animal. (Difference:  Dippers can already 
fly.)>
>
> One adjustment:  I think the people who say Archie was capable 
of powered
> flight have a reasonable argument.

I was explicitely unexplicit about whether only "such animals" 
or Archie,
too, can't fly in air. :-) Seriously, though... I can't tell 
whether
Archie's musculature was just enough or just not enough to fly 
with, but its
wing feathers (except the isolated feather... which may therefore 
not be
from Archie) are more symmetric than those of all investigated 
flying birds.
        "Already" was meant to mean (it was late at night) that 
the
lifestyle of dippers is secondary, their ancestors were able 
to fly before
they extended flight into thw water.

> My own feeling, for what it's worth:  some active, warm-blooded 
animals
who
> were flexible in hunting strategies
> developed feather precursors as a mutation and it persisted 
because it
kept
> them warm.  All other behaviors were affected by having feathers; 
they
> adapted to feathers and feathers to the adaptations.
> Call it feathers came first.

Exactly as I wrote: you start out with a fully feathered, fully 
winged
coelurosaur. Such like... (should be at
http://dinosauricon.com/genera/bambiraptor.html, but I can't 
access that
site). (Wings -- long wing feathers, +- laterally oriented glenoids,
probably the semilunate -- evolved for brooding.)

> Because of selection, a range of behaviors is being looked 
at like a
single
> strategy.
> Trees down?  Yes.  (Though, contra Tim, I still think an ambush 
leap has a
> better angle from a large rock than from a tree.)

So it lived in mountaineous areas -- neat for the fossil record 
again? :-)

> Ground up?  Yes.
> Swimming?  Yes.
> Name it?  Yes.

"Possible" or "yes"? If "yes", you are arguing for a pretty extreme
generalist... might be improbable.

*************************************
Aw. We should have had these amounts of snow in winter and not 
now in
mid-spring. The weather is getting crazier and crazier.


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