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From: frazier@oahu.cs.ucla.edu (Greg Frazier)
Newsgroups: sci.bio
Subject: Re: What distinguishes a species?
Message-ID: <31360@shemp.CS.UCLA.EDU>
Date: 29 Jan 90 20:46:39 GMT
References: <33962@ucbvax.BERKELEY.EDU>
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Reply-To: frazier@oahu.UUCP (Greg Frazier)
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In article <33962@ucbvax.BERKELEY.EDU> bwood@janus.Berkeley.EDU.UUCP (Blake Philip Wood) writes:
>I'm aware that the inability to interbreed is the standard definition
>of two populations being of differing species, but more precisely, 
>is it:
>
>a)  can't physically mate due to differing genitals.
>b)  could, but don't mate due to differing sexual lures, rituals, etc.
>c)  can mate but produce no offspring.
>d)  can mate but produce sterile offspring, ie. horse+donkey=mule.

Unfortunately, it is all of these and more.  For example, we are
currently trying to breed Lamprologus pulcher, a species of fish
from Lake Tanganika.  These fish are, for all intents and purposes,
identical to L. brichardi, even to the point of breeding.  The offspring
of such a pair breed true, i.e. each fry will be either a L. pulcher
or a L. brichardi.  Taxonomists have differentiated between the species
based upon subtle differences in scale colorings, although I have also
heard that they are different temperamentally (pulchers are supposedly
more aggressive).  I know, this sounds like splitting human beings
into different species based upon eye color, but there it is - don't
blame me, I'm not into taxonomy.

Greg Frazier
................................................................
"They thought to use and shame me but I win out by nature, because a true
freak cannot be made.  A true freak must be born." - Geek Love

Greg Frazier	frazier@CS.UCLA.EDU	!{ucbvax,rutgers}!ucla-cs!frazier