Article View: sci.bio
Article #4353Re: What distinguishes a species?
From: Russell Turpin
Date: Thu, 01 Feb 1990 21:14
Date: Thu, 01 Feb 1990 21:14
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In article <202@53iss6.Waterloo.NCR.COM>, howard@53iss6.Waterloo.NCR.COM (Howard Steel) writes: >> Are all dogs in the same species? > > NO. The main problem is usually physical disparity. When's the last time you > saw a St. Bernard - Chihuahua cross? But a St Bernard will happily breed with a large shepherd, which will breed with a medium collie, which will breed with a smallish terrier, which will breed with the Chihuahua. If one uses solely the above criterion for being in the same species, one has the problem that the relation "being in the same species" is no longer transitive. Hence, the concept of a species (as a group) disappears, to be replaced by the comparative but non-transitive relation of breedability. Russell
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!turpin From: turpin@cs.utexas.edu (Russell Turpin) Newsgroups: sci.bio Subject: Re: What distinguishes a species? Summary: So what *are* the dog species ... Message-ID: <7757@cs.utexas.edu> Date: 1 Feb 90 21:14:27 GMT References: <22448@siemens.siemens.com> <202@53iss6.Waterloo.NCR.COM> Distribution: usa Organization: U. Texas CS Dept., Austin, Texas Lines: 15