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Re: Microraptor also ate fish



On Mon, Apr 29, 2013 at 9:43 PM, Mickey Mortimer
<mickey_mortimer111@msn.com> wrote:
>
> Technically, everything is adapted to do what it does, since mutation causes 
> most changes and the species has survived.

Well, but not every trait in existence is selected for -- some are due
to drift. Intuitively I feel like it should be fairly easy to tell the
difference, but objectively I'm pretty sure we have a lot more legwork
to do.

> I was thinking more in the sense of what we as paleontologists think of as 
> "adaptations for x" not being present in a significant proportion of taxa 
> which are x.  So sure an elongate grasping pes is an adaptation for 
> arboreality, but how many species which spend e.g. >30% of their time in 
> trees actually have that trait, and how much can it be compensated for by 
> other traits?  Or alternatively, how many species which spend e.g. >30% of 
> their time in trees aren't significantly different osteologically from 
> species which spend e.g. <5% of their time in trees?  How strict/misleading 
> are the osteological correlates we look for, basically.

Right, this stuff would be very interesting to know.
--
T. Michael Keesey
http://tmkeesey.net/