Xref: utzoo rec.pets:10911 sci.bio:2696
Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!rpi!leah!gmr044
From: gmr044@leah.Albany.Edu (Gregg Recer)
Newsgroups: rec.pets,sci.bio
Subject: Re: What is a species?
Keywords: artificial selection makes species identity meaningless
Message-ID: <2495@leah.Albany.Edu>
Date: 7 Feb 90 18:01:01 GMT
Organization: The University at Albany, Computer Services Center
Lines: 48



In article  <2285@uwm.edu>  debbie@csd4.csd.uwm.edu (Debbie Forest)
writes:


>yes, all dogs are the same species.  but why then aren't wolves in the
>species too, since dogs and wolves can cross-breed?


I don't know from what wild species domestic dogs were derived, but
even if it wasn't wolves dogs might still be able to breed with wolves
and produce viable offspring.  However, those offspring would then be
infertile.  This same kind of mating barrier occurs in the
horse/donkey/mule system. 

Some general remarks:

In many cases, including dogs and cats, a large number of breeds or
varieties have been produced via artificial selection from a single
wild species.  In some cases, such as the St. Bernard/Chihuahua
example a mating barrier has been established via artificial
selection.  In a sense this mimics the process of speciation in
natural populations when geographical barriers separate a population
into two sub-populations and then
morphological/physiological/behavioral/other variations develop
between the two sub-populations which eventually render them unable
to successfully interbreed.  However, by domesticating a wild species
via artificial selection the domesticated breeds are effectively
removed from the evolutionary and phylogenetic history of the species
from which they were derived, in my view, and so asking if they are a
new species or if several new species have been created is an
irrelevant question. 



Gregg



*******************************************************************************

     "In future you should delete the words crunchy frog and 
     replace them with the legend crunchy raw unboned real
     dead frog!!"  
                 -- Inspector Bradshaw, The Hygiene Division

*******************************************************************************