Warp wrote:
>   Even if somebody doesn't know what something is, he can still know what
> it isn't.

Fair enough. You said it so confidently that I thought you had  better 
definition in mind.

>   Defining "species" based on the decisions made by groups of living beings
> (even if those decisions are instinctive) is just silly. 

I disagree. The definition of "species" that I'm familiar with is "two 
populations are distinct species if they can not or normally would not 
interbreed."  So even if tigers and lions *could* have fertile offspring, 
they'd still be different species because they're in different habitats.

>   The decision of whether two groups are of the same species should be
> doable by studying their genes only, without having to observe their
> behavior.

But the study I pointed to said nothing about the genes of the fruit flies. 
You're *assuming* it's merely "instinctive behavoir" that didn't affect the 
genes.

If your genes tell you not to interbreed, even if artificial insemination 
would work, are you a different species?  What if a fertile offspring could 
be produced, but only if humans put the embryo in a completely artificial 
environment? I.e., if the mother could not bring the offspring to term 
naturally?

Plus, of course, we can't really look at genes and tell whether the result 
will be fertile offspring.  Maybe in theory that's true, but in practice, 
while it's pretty easy to tell when the species are far apart, it might be 
very difficult to tell if the species is very close together.

>   You didn't, but you make it sound like that when you overemphasize the
> role of behavior in the definition of "species".

And to me, you seem to be completely disregarding the role of behavior. I'm 
not overemphasizing it except compared to you, perhaps. I'm just thinking 
that if human technology has to get involved to create offspring, chances 
are good they're different species. If I did genetic engineering to create a 
creature that's half human, half ape, that wouldn't make humans and apes the 
same species. And if I stick insulin-producing genes into a bacteria, does 
that mean I have a new species or what?

-- 
Darren New, San Diego CA, USA (PST)
   Serving Suggestion:
     "Don't serve this any more. It's awful."

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