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OgreMkV



Posts: 3335
Joined: Oct. 2009

(Permalink) Posted: Nov. 09 2011,12:38   

Quote (Southstar @ Nov. 09 2011,12:18)
[quote=Quack,Nov. 09 2011,10:59][/quote]
Okay,

I have a question for me ;)

It sounds awfully stupid but maybe it isn't

At what point do you stop calling a dog a dog and start calling it something else?

Thanks
Marty

That's a REALLY good question and it all depends on how you define species.  

To give you an example of the huge inconstancy in this regard, you might be familiar with Escherichia coli.  It is a massively diverse species of bacteria.  In fact, it's so diverse that only 20% of the DNA is common between all strains of it. {Lukjancenko, O.; Wassenaar, T.M.; Ussery, D.W. (2010). "Comparison of 61 sequenced Escherichia coli genomes". Microb Ecol. 60 (4): 708720. doi:10.1007/s00248-010-9717-3. PMC 2974192. PMID 20623278.}

When you get to vertebrates, you could go with something like reproductive isolation, but you have to get pretty specific.  Lions (Panthera leo) and tigers (Panthera tigris) are obviously different species, yet they can interbreed and produce reproductively capable offspring, which by most indicators would suggest they are the same species.

In short, life is squishy.  Humans want everything to be in a category and those categories to have meaning.  They don't, not really.

Wolves, dogs, and coyotes interbreed all the time.  Three different species.  Is the hybrid a wolf-dog or a dog-wolf?  

I maintain (and I may be almost alone here), that absent the medium sized dogs, the toy dogs and working dogs should be different species.  In fact, there's more diversity within dogs, than there is in all of Carnivora combined.  On the other hand, most of that diversity is in a very small amount of DNA {http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2919785/}

So, really, who knows.  I doubt anyone will ever be able to say, "look, this dog really isn't a dog".  What will be more likely is something like "Hey, 12,000 years ago, in 1995 was the first divergence of this new species of pet from what used to be called 'dogs'."

--------------
Ignored by those who can't provide evidence for their claims.

http://skepticink.com/smilodo....retreat

   
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