How did all people evolve anatomically & mentally the same?

Question

Please be short on sarcasm/cynicism. With 6 billion people living on 6 continents- how did we as a species evolve simultaneously & identically into one? Instance, the neanderthal in freezing temps would be facing different survival needs than the neanderthal in the desert. Yet, anatomically and mentally- we are all the same. Why wouldn't there be some distinction- such as organs, limbs, brain size, thought capacity, etc? We have subtle genetic differences such as skin color- but why aren't there more pronounced differences when our ancestors would have been facing a myriad of survival issues? If we were to place a tribal infant into modern society- that child would perform like any other. Achem's razor would seem to disqualify abilities to certain cultures. If it isn't needed for survival- why have it? Also, why wouldn't there still be neanderthal-like tribes in areas like S.America where tribes have been left untouched? If we're evolving- when, who & where will be the next "model"?

Answer 1

There are no Neanderthals anywhere else in the world besides Europe.  That is where they evolved.  That is why they are found nowhere else.

And there are many differences between all the people in the world.  Millions of differences.

There has not been enough time for Humans to evolve differently since the last migration of Homo Sapien.  We all are the same species.

And, part of my Thesis at college was based on modern Evolution.  I do not believe that Humans are evolving anymore. It is impossible.  

Evolution is a "Natural" process.  Humans do not follow that pattern anymore, we do not adapt to a situation, we adapt a situation to us.  Hence, no more evolution.

In summary, we are all basically the same, because we are all the same species.  You don't find much difference in spicies, otherwise we wouldn't be the same species.

Answer 2

It's not as if 6.8 billion people separately evolved into the same shockingly similar thing.  As a species, living in the same general area, our ancestors evolved into homo sapiens, all in Africa.  From there, homo sapiens migrated out of Africa and across the globe.  No one pocket of homo sapiens evolved enough from there to become a different species, clearly.

So we have homo sapiens all over the place, but there is also a sizable population of homo erectus (our most direct ancestor).  Why aren't there still prehumans around, you ask?  Because homo sapiens out-competed them.  Our species of humans had bigger brains, used tools, and organized themselves more effectively.  For this reason, homo sapiens dominated the human family, and eventually came to populate the globe.

Answer 3

Most of the above answers are really good, but different geologic groups have different traits.  You say that skin difference is subtle, when it makes a huge difference in survival.  The darker a person's skin is, the more they are able to cope with the intense UV light.  Africans, Indians, and Australian Aborigines all have dark skin to deal with their location close to the equator and the heat the area has.  Pale folks from northern Europe are not able to deal with the intense UV, and get sunburned.  The northern Europeans also tend to have wider noses, and rounder faces than people from, say, the mediteranian areas.  This allows for their sinus cavities to warm the frigid air a bit before hitting the delicate lungs.  As for the tribal differences, there isn't a tribe that has been untouched on the world... yes, there are a few isolated groups that may have been removed for the past couple hundred years, but they have issues as they have a reduced gene pool.  There is also the idea that we retain many of our abilities that perhaps we don't "need" anymore simply because we haven't needed them for a very short period of time.  It really wasn't THAT long ago that we began civilization - not even a million years... we still retain some of our abilities because we might still end up needing them somewhere along the line... better to have it and not need it, than need it and not have it right?

Answer 4

Great Question!

74,000 years ago, the Sumatran volcanic explosion of Mount Toba, which was the greatest natural disaster in the past 2 million years, and which caused a prolonged nuclear winter, created a "bottleneck", from which only an estimated 2-10,000 hominins survived...

From this rather severe pruning, which almost caused our extinction, all the genetic material that exists today, came from these 2-10,000 survivors 74,000 years ago, which in geologic time, is a mere instant!

Answer 5

Good question, but there's also a really good answer. The most recent common ancestor of all modern humans did not live all that long ago, in evolutionary terms. There aren't more pronounced differences in the different geographically isolated groups simply because there wasn't enough time for big differences to emerge. This has essentially been demonstrated with mtDNA studies, among other things.

The fact of the matter is, we haven't all "evolved the same." We just haven't diverged very much.

As far as we know, Neanderthals emerged and only lived in Europe. But hey, maybe we just haven't found their South American skeletons yet.

Your assertion that "when there is a divergence the stronger kills the weaker" is patently false. Cite your source.

Answer 6

It is very likely that the population of modern humans came from a genetically much more diverse species.  We still likely all came from relatively small numbers of ancestors.  I don't buy the Toba argument as being very reliable but it does seem that small numbers of ancestors did account for most of the people on earth today.  It would be like the Romans expanding and taking over the whole world.  That sort of thing probably more likely happened several times to a less extreme degree.

Answer 7

But people survive today worldwide although they all have differing attributes! But at the same time modern man has problems that his neanderthal never had to deal with! We have to work with things that are close to us yet our eyes are really made for viewing things far away! We have to deal with stresses that never were around when man first evolved! We have no releases like they had! Survival means being able to adapt and thrive not just make it to the next day! You can take someone from the equator today and they can live above the arctic circle and vice versa. All of us can adapt, humans have learned to do so!

Answer 8

It's easier for me to believe that we were created, than to have just accidentally came about. Think about it. The human body is so complex. If one gene of our DNA is compromised, our body would have deffects. Think of how new life comes into the world. How by chance, could a man and woman evolve s*x organs that together, are perfectly desinged to bring new life into being?

Really think about how complex our universe is, and ask yourself, "could this really have come into play by accident?"

Answer 9

About 70,000 years ago, a geological eye blink, we were reduced to about 10,000 individual humans and by going through this " bottle neck " we are remarkable similar, though not exactly, a species.

Not enough time and no geographic isolation in this world to speciate humans.

Answer 10

We aren't homogenous. We have different racial gestation periods and twinning rates. Some have different lifespans, and hit menopause in their twenties.

http://mathildasanthropologyblog.wordpre...

Europeans can digest lactose in adulthood, most other humans can't. People with recent hunter gatherer ancestry are unable to cope with high carbohydrate diets, and get fat and diabetic on them. Europeans have a higher rate of gluten intolerance, as grain is recent to our diet.

And I'll get flamed for saying it, there's an IQ gap between populations too. Plenty of evidence for it.

There's just not been enough time for bigger differences to be selected in.

I suggest the next step in our evolution is 'Homo Urbanis'!