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Re: Paradoxically temporal



>George, et al:
>
>    This definition for speciation fits best, considering all the problems
>with other definitions:  E.g. Ability to mate - Tigers and Lions are
>separate and distinct species, yet they can mate, and their offspring
>(Ligers, and Tigons) occasionally can sucessfully mate as well.  (By
>sucessful I mean resultant offspring).
>



Definition, or recognition?   Diagnoses are used to recognize the
occurrence of speciation, not to define it as such.

An analogy -- having the common cold is "defined" by the invasion of a
virus into the body.  We can tell such an invasion has occurred by
observing "diagnostic" features - runny nose, headache, and so on. These
symptoms don't "define" a cold, they simply tell us that a cold has been
caught.

Of course, this does mean that our ability to recognize species will not
match the actual number of species in nature. Even with modern molecular
methods, cryptic species will  defy our capacity to tease them out, and as
stated earlier, the inclusiveness of a species will increase as the range
of diagnostic tools available to us decreases.


chris


-=--=--=--=--=--=--=--=--=--=
Christopher Brochu

Postdoctoral Research Scientist
Department of Geology
Field Museum of Natural History
Lake Shore Drive at Roosevelt Road
Chicago, IL  60605  USA

phone:  312-922-9410, ext. 469
fax:  312-922-9566

cbrochu@fmppr.fmnh.org