How did the different human races evolve?

Nope.

Species: [n] (biology) taxonomic group whose members can interbreed

says it all. DNA rules, not looks or relatively minor adaptations, sorry.

 

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if one species penis doesn't fit in anothers vagina they cannot mate. They cannot interbreed. It has nothing to do with possibly matching DNA.

 

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I see your problem with the concept, but stricly speaking only until the separation has taken long enough for any changes to become encoded long-term into the DNA, the differences are really superficial.

That's simply how it works: if say a hominid has a 'sexual dysfunction' in the sense his reproductive organ is too big or too small for the general female organ, he will not reproduce, unless there is a similar female, at the right time etc. If there is, deviation from the norm can continue, if not, no reproduction, and end of problem.

So there is quite a bit of leeway in how oddly different members of one and the same species can look, and still be able to interbreed in most cases.

Same goes for humans. Most reasons inhibiting interbreeding are social, political and racist. Apartheid does not prevent mixed races though, although some people find the mere thought of interbreeding equally 'impossible' as if it were truly physical, which it isn't.

So, to come back to the topic, there are no 'races' of humans, or 'dogs'. Just different breeds, until finally one day one group of humans splits off that NO other humans can have offspring with, even in vitro. Only then can we speak of a different species, really.

 

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whatever.

If that is what you think.

 

And so does every biologist not living on planet spuriousmonkey, if you like to have it put that way.

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Every biologist minus one I would think. Happen to have a PhD in evo-devo.

 

Let's go over your post again then:

Species: [n] (biology) taxonomic group whose members can interbreed


You conclude that DNA says it all, although DNA is not mentioned in the original statement. Could it be that maybe your brain made an association of DNA to this statement when you read it, but that possibly your brain jumped to conclusions.

Obviously 2 organisms cannot mate if their respective DNA is too disimilar. But could it be that the original statement also includes other causes for the inability to interbreed? Such as physical isolation (a major cause of evolution of new species), behavioral isolation (a major cause of the evolution of new species), and maybe also physiological incompatiblity?

In the case of dogs they are classified as one species, because they are what you could call 'a freak of nature'. They have been shaped by another species, us humans. This human species has the technical capability of letting the Danish dog mate with the tiny chihuahua. But as I said in the first post. In nature they could not interbreed because of physiological incompatibilities and would rapidly diverge into separate species.

A related question is: when a species is different enough to be a separate species. There is never a single point in time when it suddenly is clear that a species is a species. But the chihuahua and danish dog would fill such different niches in nature and show such different physical properties that they could easily be classfied as different species.

Obviously neither the Danish dog or chihuahua would ever survive in nature as a species for ery long, so speculation on this matter is purely theoretical in nature.

 

http://www.talkorigins.org/faqs/evolution-research.html#cichlid-fish

According to this definition the two dog breeds would have undergone speciation if these species were found in nature. They are reproductively isolated.

 

Good for you!

I mean that btw, but you should also realise that it's more important if somebody bothered to hire you after getting it.

'not living on planet spuriousmonkey', like I said.

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I know DNA is not holy, but I also know taxonomy IS based on that somewhat largish distinction.

Also that if you look closer and closer, definitions get iffier and iffier. Bacteria are a disaster to properly classify since they exchange their DNA with other bacteria at a ridiculous rate, they found.

But you have to make distinctions somewhere and it that case DNA is a pretty good classifier.

Dogs are a species 'shaped by' humans, indeed, but not created. Freaks, also true.

Like us. Neotenic freaks. That's why we get along so well.

 

Maybe you should take you head out of the clouds and try to be open minded. You might learn something.

 

Yeah, whatever.

 

troll.

 

If anyone here is trolling here... but I guess the remark about getting hired struck too close to home for comfort.

Have fun.

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I wasn't even going to bother with a proper response after your first arrogant response, but then I supported my position and countered yours. The only thing you could do is to claim authority. All biologists think like me you claim. Obviously a false statement. And of course, if the authority claim fails you can always claim that I am a lousy scientist.

It could have easily turned into something productive. And as usual nowadays everybody knows best, without even thinking about the others remarks.

 

For instance, did you ever bother to check your position before continueing in the discussion? Other than to find a single quote? Did you ever check what biologists think on the matter?

I did.

 

You two should calm down, you're getting hysterical.

Man has played at being God with dogs! Man became the selector, isolating differences as nature does. OK a chih is the same species as a great dane, but give or take a few thousand years they could break off into a different sub-species (producing an infertile hybrid) and then into a species.

As an example it serves well to educate the non beleivers in evolution of how it works and what humanity have done with the knowledge - whether they realised the principle of it or not.

 

Look at the recent study on foxes... thru selection a virtually new species of foxes was created that is extremely tame, to a point of being dog like. These foxes will soon be available as pets... this was done with a few generations.. to think that human races do not differ do certain degrees based on selective breeding (ie jews only marrying jews) and isolation is extremely ignorant...

 

I think the point is that all so-called human 'races' can & do interbreed with healthy, viable, non-sterile offspring, whereas those people that wish humans were different 'races', wish that weren't true

http://www.lovelongears.com/about_mules.html

 

Yes: Such differences are real and demonstrated by growing scientific evidence.

http://www.lrainc.com/swtaboo/stalkers/jpr_insight.html