Today in Bio we were learning about species differentiation and what defines a species; specifically, that the definition of a species is a group of organisms that reproduce together and don't produce hybrid offspring. So technically, if a species doesn't reproduce together because of geographical or behavioral reasons, they're a different species. Canines, for example-- wolves and dogs are perfectly capable of reproducing and creating healthy cross-breeds, but they don't because they either were geographically separate, or, now that dogs are everywhere, they have too many behavioral differences-- wolves have a complex social hierarchy that is very different from that of dogs, and they just don't want to interbreed. I mean, it happens, but it's rare.
I personally see one major issue with this definition-- humans. We're one species, right? And yet thanks to geographical reasons, our phenotypes have developed to be quite different. If it hadn't been for exploration and colonization, the trend might have continued, creating multiple distinct populations that were so drastically different that they would appear to be completely different species. As it is, someone with a complex knowledge of biology but not a great knowledge of humans and the earth might think I was a different species than an Aborigine.
Of course, humans are interfertile, so we're one species. And yet, dogs and wolves are interfertile. Different populations of humans with geographical separation didn't intermarry until colonization and exploration put us together. And then there's the behavioral thing-- dogs choose not to interbreed with wolves for societal reasons. That sounds a hell of a lot like racism and culturalism to me. It's not that they couldn't if they wanted to, it's just that they don't.
Now, I'm not saying different races are different species, because honestly at this point there's enough interracial marriages that it wouldn't work anyway, and I've seen very few African-Americans who didn't look like they had a great big scoop of European genetics mixed in, thanks to American slavery. Humans differ from dogs in that we're intelligent enough that we can overcome geographical and behavioral differences that might otherwise continue to differentiate us into several species. Though I kinda wonder what would have happened if we had taken a little longer in the Dark Ages.
What I am saying is that human beings were a clear example of the failure of the "populations that don't interbreed for geographical or behavioral reasons are different species" rule, and that the biologists should reevaluate their guidelines to make sure that there is an actual, legitimate reason why two humans from different parts of the world are unquestionably the same species as the but a husky and a wolf are different. Maybe "wolf" should just be made into another breed of dog? I don't know. But it's kinda bugging me.