🚀 go-pugleaf

In article <2285@uwm.edu> debbie@csd4.csd.uwm.edu (Debbie Forest) writes:
>In article <3251@hp-sdd.hp.com> andrea@hp-sdd.UUCP (Andrea K. Frankel) writes:
>>
>>Physical difficulties notwithstanding - if you (ahem) gathered sperm
>>from a St.  Bernard and artificially inseminated a Chihuahua in heat,
>>you would get offspring which were themselves fertile.
>
>yes, all dogs are the same species.  but why then aren't wolves in the
>species too, since dogs and wolves can cross-breed?

The simple case of cross-fertilization (with or without fertile offspring)
is not sufficient to define a species.  The other half of species definition
is the ecological niche the new species occupies in comparison to the parent
group.

When an adaptive shift occurs which allows the offspring to occupy a niche
which tends to isolate the new group from the old further adaptations in the
new group can accelerate the isolation of the new species.

Wolves and Dogs (canis lupus vs canis familiaris) occupy different niches
in general, but not so different that contact is eliminated.  Some purists
would like to say that lupus and familiaris are "sub-species", but general
usage has its effect as well.

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Just some additional fuel for the discussion to justify being in sci.bio ;-)
-- 
Gregory G. Woodbury
Sysop/owner Wolves Den UNIX BBS, Durham NC
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