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Re: Raptors climbing trees?
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.