Re: Raptors climbing trees?

[ptnorton <ptnorton@suscom-maine.net>]

Graydon wrote ( in part)

> How do you tell the adaptation from the exaption?  Especially initially?<

The answer is that you can infer exaptation, but you can observe adaptation. 
An exaptation is the opportunistic use by an animal of a preexisting 
characteristic that enhances its ability to produce offspring in a changing 
environment. If that characteristic is selectively spread by natural 
selection through a population over time, it is seen in the fossil record as 
an evolutionary adaptation. Given the resolution of the fossil record it is, 
I think, unreasonable to expect to see isolated exaptation events, but not 
at all unreasonable to see, as we have, the spread of a preferentially 
adaptive characteristic through a population over time.

PTJN