Lack of Human varieties. Genetic "cleansing" through history?

We look into the animal kingdom and see a vast variety of each species, yet for humans, this variety is extremely limited.Taken from another page:

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Genetic evidence

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Investigation of the patterns of genetic variation in modern human populations supports the view that the origin of Homo sapiens is the result of a recent event that is consistent with the Out of Africa Model.

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* Studies of contemporary DNA, especially mitochondrial DNA (mtDNA) which occurs only in the cellular organelles called mitochondria, reveal that humans are astonishingly homogeneous, with relatively little genetic variation.1,5
* The high degree of similarity between human populations stands in strong contrast to the condition seen in our closest living relatives, the chimpanzees.2 In fact, there is significantly more genetic variation between two individual chimpanzees drawn from the same population than there is between two humans drawn randomly from a single population. Furthermore, genetic variation between populations of chimpanzees is enormously greater than differences between European, Asian and African human populations.

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Take a look at cats: Small house cats of infinite colors and sizes. Then you have some house cats with 6 toes. Some with no tail. Some with no hair whatsoever. and then onto a larger scale: tigers, lions, pumas, cheetas, jaguars...on and on and on. Its like this with most creatures. Vast varieties of a given species. Each with features which help them survive in their local ecosystem. But no matter the ecosystem, modern humans have no distinct features which would help them survive in say, a frozen climate versus an equatorial climate. With only small exceptions, we are all the same. Not to confuse this with comparing humans to chimps, to orangutans, gorrillas, etc. When I talk about different varieties, I'm implying different human varieties, not primate varieties.
There were 6 different known hominid species.
1. Australopithecus anamensis
2. Australopithecus afarensis
3. Australopithecus africanus
4. Australopithecus aethiopicus (or Paranthropus aethiopicus)
5. Australopithecus boisei (or Paranthropus boisei)
6. Australopithecus robustus (or Paranthropus robustus)A couple of these lines branched off into multiple human species.
Out of Africa and the middle east, came homo sapiens, the modern human. In Asia, Homo Erectus. In Europe, Homo neanderthalensis (Neanderthal). Some scientists think there could have been even more.
What happened to the last 2, and the possible unknowns, and why?
There is fossil "evidence" of different, unique human varieties having existed, but for some reason they are gone. To suggest that the other varieties were unfit for survival would be questionable, so why did they die out? They had all the same tools for survival we do. Perhaps less intelligent, but even the less intelligent human varieties would have been more intelligent than your average animal or primate which still survives and thrives today.
Given man's tendency to hate and kill anyone different throughout history (men will try and wipe out an entire race of people simply for an ideal), is it possible that entire varieties of humans were wiped out by a "dominant" human variety, and not by the hands of evolution? We have seen "ethnic cleansing" in our own time, and throughout history. Is it possible that they were killed off? Not that we need to find a reason or motivation for it. We have witnessed it happen for no good reason, so who is to say that it couldnt have happened?The page I quoted from above, was something I found while editing this, and I was surprised to see there really was something to what was on my mind.
http://www.actionbioscience.org/evolution/johanson.htmlThis message has been edited by SantaClaus, 03-23-2006 09:28 PM

You are mixing apples and oranges. Varieties of house cats are, indeed, varieties of the same species. But when you go to tigers, lions, pumas, cheetas, jaguars, you are talking about diverse species. For the human case you might as well be talking about chimpanzees, gorillas, bonobos, orangutans.You need to clarify whether you are wanting to discuss varieties within the human species, or closely related species.

Post deletedThis message has been edited by SantaClaus, 03-24-2006 08:25 PM

Edit your OP (message 1 in this thread). Update it to clarify what it is you are variety of human.When you are ready for us to take another look, reply to this message.

I think I polished it up pretty well. Let me know what you think.

Thread moved here from the Proposed New Topics forum.

Well, the fact that they're not here now would seem to suggest that they were, indeed, killed off.Or did you mean by homo sapiens? That's possible, sure. Going from a question in the first post, what makes you think that doesn't constitute a kind of evolution?

If the neaderthals and modern humans had sterile offspring and there was a greater tendancy for a neanderthal to want to breed with a M. human than a M. human to want to breed with a neandethal, wouldn't that result in a decrease in the population of neanderthals?...until it reached zero?Or were you also including sexual selection in the phrase "killed off"?

By killed off, I meant, murdered. The evidence shows that there was no interbreeding between neanderthal and homosapiens. Neanderthal's DNA was so unique that it has been considered an entirely different species. What evidence is there to suggest that neanderthal's offspring were sterile?

Evolution isnt a killing off of a species. Its a gradual mutation. And yes, I meant killed off by homo sapiens.

There is no need for a large vairiety of outward physical variation in humans. We all survive, particularly in todays world, even the most unhealthy least fit humans survive and reproduce.Humans adapt their environment to fit to their needs.Thanks to our minds we can survive almost anywhere with almost no regard to our physical features. There are a huge amount of physical differences in human popualtions though.I am sure we killed off any recent species of human relatives. Homo floresensis was probably one of the last populations of contemporary human relatives on the planet. After homo spaiens arrived on that island they were probably slowly killed off, maybe not entirely by human hands but also by our ability to out compete them for food supplies.People are also born with 6 toes or fingers, webbed feet or hands and tails sometimes.

No, extinction is part of evolution. Look in the fossil record - over 99% of the species we know from fossils are completely extinct. Extinction is largely the ultimate destination of any one species, so I'd say that's definately part of evolution. There's no such thing as a "gradual mutation." Mutations are basically instantaneous.

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There is no need for a large vairiety of outward physical variation in humans. We all survive, particularly in todays world, even the most unhealthy least fit humans survive and reproduce.

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That's only true in the industrialized, tehchnologically-advanced parts of the world.The majority of the world doesn't have access to state of the art health care.Many, many humans still die, before reproducing, from starvation and preventable illnesses.

All a genetic mutation is really is just a base pair change and crossing over in sperm or eggs. That single event is basically instantaneous. But mutation of a species into another species is gradual.This message has been edited by carini, 03-25-2006 12:52 PM

Again, species don't mutate. Genes mutate. Species evolve; when they become new species, that process is called "speciation" and it can indeed be gradual. It can also be sudden.