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Re: Definition, please
At 08:34 AM 5/17/97 -0700, T.A. Curtis wrote:
>> Are they exaptions of gastralia?
> I know gastralia. I don't know exaptions. Can someone please
S.J. Gould and E. Vrba coined the term "exaptation" for the previous concept
Aptation: a structure, behavior, etc. fit for a function.
Adaptation: a structure, behavior, etc. fit TOWARDS a function.
Exaptation: a structure, behavior, etc. modified FROM a previous function to
a new function.
For example, the limb bones of tetrapods are adaptations for crawling on
land, and are exapted from the sculling/swimming fin bones of more primitive
The feathers of early birds were adaptations for flight, but almost
certainly exapted out of some earlier use (thermoregulation? display?).
Hope this helps.
Thomas R. Holtz, Jr.
Vertebrate Paleontologist Webpage: http://www.geol.umd.edu
Dept. of Geology Email:firstname.lastname@example.org
University of Maryland Phone:301-405-4084
College Park, MD 20742 Fax: 301-314-9661