Why is there only one existing species of modern man and woman?

Have we artifically classified ourselves as somehow so unique, and thus, separated ourselves from the rest of 'biologica', in a convoluted way that does not define 'human' as common to this world'? If not, then why only one extant 'human'? http://en.wikipedia.org/wiki/Human_taxonomy http://en.wikipedia.org/wiki/Human

Humans and great apes, gorillas, and chimpanzees, nearest 'like kinds' living on this planet, cannot naturally interbreed, thus, regarding biological speciation, are recognized as different species. That's pretty easy. But, apparently, even giraffes, for instance, come in specific 'flavors'. Science calls this process, 'speciation'.

In everyday usage, a species is often defined as a (group of organisms capable of interbreeding and producing fertile offspring," and, that is good enough (http://en.wikipedia.org/wiki/Species). Science, of course, has been thinking about this for a long time and has subdivided the definition ever more finely.

About those giraffes: http://funtasticus.com/20080130/giraffe-baby/ (I've thrown this into the mix just for the ‘cuteness’ factor for your entertainment. Compare the human vs giraffe eyeball, size, yikes!). It seems now, however, because of a recent taxonomy reclassifcation, six, or, maybe even up to eleven species of giraffes are roaming around. http://scienceblogs.com/grrlscientist/2007/12/giraffe_species.php

So, giraffes, who, as a group, to me at least, look pretty much alike, and, are, in fact, not a single specie, at all, (which, no doubt, must make Friday night happy hour at the local giraffe pub, pretty frustrating). Good thing this is not part of the human condition.

If, as Albert Einstein liked to refer to God: 'The old one', created this huge amount of diversity in the biological world, so many, very similar, ''species', exist, why not us? Of course there have been other 'hominid' and human species in our prehistoric past climbing through the tree of evolution, whatever. But, oddly onnly one remains--for us--but not for the rest of the creatures on 'Noah's Ark'.

Why?

Again begging the question: Why, now, in our time, is there still only 'one' living human specie?

Your thoughts always welcome.

G H Diel

www.ghdiel@exoptica.com