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Did humans evolve into separate races that differ in mental traits?


  

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  1. 1. Do you believe that there are racial differences in intelligence?



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I wrote:

 

 

Lol, are you serious? You brought up the "25%" hard demarcation now you are saying *I* am confused?

I'm taking one point at a time.

How do you explain this:

 

fsthe3.png

 

Please answer this question.

 

 

Are we clear that Templeton is wrong about "25%"?

 

They are as strict as species, being recorded in the ICZN.

 

So how could you say race isn't a biological category if you don't even know what one is? I would say it's a category used by biologists to make predictions which hold. It's not complicated. Race satisfies this. If we define race by ancestry or similarity why doesn't that create discrete categories? An individual either shares ancestry or is more similar to another individual versus a third individual or they aren't.

 

Yes, your claim that higher diversity in Africans invalidates a taxonomic distinction is false. Race is defined by shared ancestry or genetic similarity. Africans share ancestry and are more genetically similar vis a vis Eurasians.

Well look at this. How would you divide that first?

The boundaries can be touching. Hybrids don't invalidate taxa.

Geographic populations? Like "people in London"? Do I have to explain why this is different from race?

 

 

The question was whether Neanderthal DNA was doing anything.

 

Lewontin's claim that Fst in itself can invalidate taxa (of course only applied to human race, no socio-political motives I'm sure) is false and therefore a fallacy.

 

 

Can you give some genetic indication or evidence of human subspecies? All humans are the same species and part of the same gene pool and flow.

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I don't respond to stupid posts.

 

 

Ignorant possibly, since i am openly asking for you to back up your assertions, stupid would indicate something else. It is a fact that all humans can be traced back genetically to a specific place in africa. I happen to be predominantly one of your purported subspecies, I'd like to know how you can back up that assertion with a little something other than baseless assertions based on skin color..

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Ignorant possibly, since i am openly asking for you to back up your assertions, stupid would indicate something else. It is a fact that all humans can be traced back genetically to a specific place in africa. I happen to be predominantly one of your purported subspecies, I'd like to know how you can back up that assertion with a little something other than baseless assertions based on skin color..

 

I don't respond to stupid posts.

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I don't respond to stupid posts.

Based on the fact that you keep responding to them, I'm glad you agree that Moontanman's posts aren't stupid. Perhaps you would be courteous enough to respond in kind and make some intelligent posts that answer his questions?

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Largely from another race thread:

1) If you're talking about genetically related groups, then generally the correct terminology would be populations, rather than races. In population genetic context, the term "races" is generally used to describe different karyotypes within a species.

2) Yes, distinct human populations exist - see Rosenberg et al.

3) In some cases distinctions are useful e.g. Scandinavian populations are ~90% lactose tolerant, East Asian populations ~10%. There are some ethnically associated genetic disorders (e.g. sickle cell anemia, Tay Sachs disease, etc.) and some ethnically specific drug metabolic responses that can be quite dramatic, even fatal. So identifying distinct human populations is possible and worthwhile.

4) However differences in human populations are generally clinal, and gradients of genetic diversity exist between each genetic cluster of human populations, making the separation into discrete "races" problematic in many instances.

5) Significant, long term gene flow between populations is evident in genome comparisons of human populations. There is no such thing as "racial purity" in a genetic sense.

6) Genetic clusters of humans do not correspond well to ethnically defined "races". E.g. Most human genetic diversity is within African populations ethnically defined as "black", Mediterranean Arabic communities are genetically closer to Europeans than Middle Eastern Arabic populations, etc.

7) Intelligence is a complex trait, with both heritable and environmental components that interact dynamically. Due the fuzziness of human populations and complexity of the heritability of intelligence, saying anything concrete about the IQ of specific racial groups would be speculative and wrought with autocorrelation.

Edited by Arete
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I have corrected my post as I am apparently no good with the newfangled phone/tablet thingy. Anyhow, a specific definition is still lacking as far as I can see. However, one particular recent claim seems to betray a considerable lack of understanding of the data:

 

 

Yes, your claim that higher diversity in Africans invalidates a taxonomic distinction is false. Race is defined by shared ancestry or genetic similarity.

 

And here is the issue. If you want to assert relatedness, that is a relatively trivial point. Obviously, with the right markers you can be distinguished from your relatives, which is obviously a finer resolution than anyone would claim for a category such as "race". How can a broader categorization then be made if we do not assess overall gene flow? And how can we assess that without looking at genetic variation? See, the point is that we all share ancestry. Now if you want to build categories, the question becomes how close we are related. And trivially, the closer we are, the smaller the variation and the higher the resolution of the analysis needs to be to distinguish groups.

As I said before, trivially it is obvious that we can use genetic information to create groups of almost arbitrary resolution.

That, however, is not your claim. You claim that there is a magic line which somehow makes a certain level of category (i.e. race) an obvious entity once we start looking at multiple loci. You further claimed that

a) somehow, race is clearly defined by genetic similarity and therefore is different from the common usage of population

b) subspecies are clearly defined by some measure that you failed to mention

 

What this demonstrates, is the a lack of awareness of the contexts these categories are used. Obviously, using different levels of resolution and uniqueness we can create groups of varying specificity and yes, we could select a method that allows us to roughly distinguish the human population into 5 or more groups. The point, again, being that we can more or less arbitrarily define the resolution we need (assuming we have decent markers) for certain questions (such as trace movements of certain populations, estimate gene flow between groups etc.). Yet it is clear that the resulting groups themselves are only relevant and useful in specific contexts. Or in other words, to claim that there are precisely 5 races/subspecies/populations is about equally right as claiming there are 25 or more, if we use sufficient markers.

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What this demonstrates, is the a lack of awareness of the contexts these categories are used. Obviously, using different levels of resolution and uniqueness we can create groups of varying specificity and yes, we could select a method that allows us to roughly distinguish the human population into 5 or more groups. The point, again, being that we can more or less arbitrarily define the resolution we need (assuming we have decent markers) for certain questions (such as trace movements of certain populations, estimate gene flow between groups etc.). Yet it is clear that the resulting groups themselves are only relevant and useful in specific contexts. Or in other words, to claim that there are precisely 5 races/subspecies/populations is about equally right as claiming there are 25 or more, if we use sufficient markers.

 

 

Indeed - a standard caveat of K means clustering http://varianceexplained.org/r/kmeans-free-lunch/

 

Another caveat is the vagueness of the term subspecies. "In practice, the subspecies may be a useful tool, but must be used with caution and pretty much requires familiarity with the particular species and what philosophy has been used to name the subspecies within that species."

 

One can make an argument that human populations represent subspecies under a particular philosophy or set of operands to suit a given purpose, although I would argue that clinal variation and long term, ongoing gene flow would stand in the way of any widespread acceptance of such a proposal.

Edited by Arete
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Arete hit it on the head. i don't really understand why whether humans have subspecies or not is even relevant, we could pull up an IQ chart by country instead and the pattern would still show. Macro race categorizations are simply morphological phenotypes. Disease resistance and liability are more geographically determined, and IQ is culturally determined but still mostly genetic in inheritance. IQ discrepancies are a relatively new phenomena. Race is clinal in it's spectrum but the extremes still exist. We are all the same species but overlap with differing averages in traits, race is simply a correlate with intelligence it is not a causal factor, gene expression is.

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Moderator Note

Over 9000, if you can't post in this thread without resulting to insults then you will find that you will not be able to post at all. Furthermore, resorting to calling someone asking you to back up your claims stupid is rather disingenuous of you, and a particularly poor way to hold discussion. Such actions are also prohibited on this forum, so I would ask you to refrain from them in the future.

 

Do not reply to this note within the thread. And just to be clear: you will be suspended if your attitude doesn't make a rapid change.

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https://en.wikipedia.org/wiki/Continuum_fallacy


That, however, is not your claim. You claim that there is a magic line which somehow makes a certain level of category (i.e. race) an obvious entity once we start looking at multiple loci. You further claimed that

a) somehow, race is clearly defined by genetic similarity and therefore is different from the common usage of population

b) subspecies are clearly defined by some measure that you failed to mention

 

No, all taxa are defined by the same criteria, ancestry or genomic similarity, which are largely the same thing in practice. "Population" is a much wider term and includes things like "people in London" or "people with blue eyes". It's really a semantic distraction and very dishonest to use that word when talking about race. It's actually a politically motivated euphemism effort, I'm sure. To silence people by policing their language. Race is a specific type of population.

 

Race is just a word usually applied to infrasubspecific human divisions.

 

Race can be viewed at multiple levels. Here you can see Caucasoid/Mongoloid/Negroid is an obvious first division

http://www.scs.illinois.edu/~mcdonald/PCA84pops.html

and then you can subdivide as many times as you want. There isn't a fixed grain of resolution for operationalising a spectrum.


!

Moderator Note

Over 9000, if you can't post in this thread without resulting to insults then you will find that you will not be able to post at all. Furthermore, resorting to calling someone asking you to back up your claims stupid is rather disingenuous of you, and a particularly poor way to hold discussion. Such actions are also prohibited on this forum, so I would ask you to refrain from them in the future.

 

Do not reply to this note within the thread. And just to be clear: you will be suspended if your attitude doesn't make a rapid change.

 

 

I think it was somebody asking to repeat myself.


Largely from another race thread:

1) If you're talking about genetically related groups, then generally the correct terminology would be populations, rather than races. In population genetic context, the term "races" is generally used to describe different karyotypes within a species.

 

No, this is just semantics. Many scholars use the word race for populations defined by ancestry or similarity. You can call those "popualtions" if you want to pretend you're not talking about race. Race is the historical and common term for populations defined by ancestry or similarity. See eg. Kant, Darwin, Mayr. What difference does it make?

 

2) Yes, distinct human populations exist - see Rosenberg et al.

Which are also called races. QED.

3) In some cases distinctions are useful e.g. Scandinavian populations are ~90% lactose tolerant, East Asian populations ~10%. There are some ethnically associated genetic disorders (e.g. sickle cell anemia, Tay Sachs disease, etc.) and some ethnically specific drug metabolic responses that can be quite dramatic, even fatal. So identifying distinct human populations is possible and worthwhile.

 

Also we call them races.

 

4) However differences in human populations are generally clinal, and gradients of genetic diversity exist between each genetic cluster of human populations, making the separation into discrete "races" problematic in many instances.

Clinal with significant clustering. Perhaps mostly clustered. One can even divide perfect clines. It's called operationalisation. "Problematic" for scientific or socio-political reasons?

5) Significant, long term gene flow between populations is evident in genome comparisons of human populations. There is no such thing as "racial purity" in a genetic sense.

 

Sure. This is quite normal for subspecies.

6) Genetic clusters of humans do not correspond well to ethnically defined "races". E.g. Most human genetic diversity is within African populations ethnically defined as "black", Mediterranean Arabic communities are genetically closer to Europeans than Middle Eastern Arabic populations, etc.

Wrong. See eg. Tang 2005.

7) Intelligence is a complex trait, with both heritable and environmental components that interact dynamically. Due the fuzziness of human populations and complexity of the heritability of intelligence, saying anything concrete about the IQ of specific racial groups would be speculative and wrought with autocorrelation.

 

Saying something "concrete"? Is anything "concrete"? We can say there is a consistent correlation between race and IQ, persisting between and among very different nations and political systems, and after adoption. We can say IQ genes are not evenly distributed among races. Those are facts. Are they "concrete"? Human "populations" (aka races) aren't any more "fuzzy" than wavelength bands. This is the problem though isn't it? We don't want to imagine that races have different intellectual capability on average, for emotional and career reasons, so everything suddenly becomes "fuzzy". It wouldn't be "fuzzy" if we were discussing the size of Larus gulls. Even the heritability of height of human races (which is also developmentally complex) wouldn't be a problem I think. If you said Maasai were tall and Japanese were short, or that South Koreans were the tallest people in Asia, for example, I don't think people would suddenly get all itchy and say "it's complicated".

Edited by Over 9000
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I think it was somebody asking to repeat myself.

 

 

 

I think you are incorrect, so far you have done nothing but arbitrarily group people by your criteria. You keep comparing them with sub species of other animals but a sub species would be a genetically isolated group and no group of humans are genetically isolated. You make lots of assertions but you do not support them with anything but assertions. So far your evidence is not exactly mainstream science.

 

Even the idea of races is flawed, how exactly do you define a race? Skin color? No, Dark and light skinned people do not separate out all around the world in the same way. An example would be Australian Aborigines, probably one of the most distinct populations and closer to being genetically isolated than almost any other group and no more related to other dark skinned people than europeans. People of India often have dark skin but no other "African" traits.

 

So i ask you to define your three races "Caucasoid/Mongoloid/Negroid" what is the defining characteristic of each of these?

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I think you are incorrect, so far you have done nothing but arbitrarily group people by your criteria. You keep comparing them with sub species of other animals but a sub species would be a genetically isolated group and no group of humans are genetically isolated. You make lots of assertions but you do not support them with anything but assertions. So far your evidence is not exactly mainstream science.

 

Even the idea of races is flawed, how exactly do you define a race? Skin color? No, Dark and light skinned people do not separate out all around the world in the same way. An example would be Australian Aborigines, probably one of the most distinct populations and closer to being genetically isolated than almost any other group and no more related to other dark skinned people than europeans. People of India often have dark skin but no other "African" traits.

 

So i ask you to define your three races "Caucasoid/Mongoloid/Negroid" what is the defining characteristic of each of these?

 

In pretty much every post I define race by ancestry or genomic similarity. Sorry if you have a reading comprehension problem.

 

"If I was helpful, let me know by clicking the [+] sign ->"

 

Is there a [-] sign?

 

You can pretend I define race by "skin color" if you are unable to contradict me. If that makes you feel better.

No, all taxa are defined by the same criteria, ancestry or genomic similarity, which are largely the same thing in practice...

 

Race is the historical and common term for populations defined by ancestry or similarity. See eg. Kant, Darwin, Mayr. What difference does it make?

 

You keep comparing them with sub species of other animals but a sub species would be a genetically isolated group and no group of humans are genetically isolated.

 

Wrong. Hybrids don't invalidate subspecies. "Race" is a word used to refer to infrasubspecific subspecies-(in the broad sense) among humans.

Edited by Over 9000
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Sorry if you have a reading comprehension problem.

 

 

 

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Moderator Note

 

Applies to you as well. One need not go back very far to find a post where you were told not to respond to a modnote but then you did, and were also your attitude need to change, and it hasn't.

 

Any chance you were previously registered here as Mikemikev?

 

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Moderator Note

 

Applies to you as well.

 

 

No it really doesn't. There's a big difference between not doing what you are told and lying about what people said.

 

Let's get this straight. My opponent is demonstrably lying about what I am saying. And you are telling me my "attitude need to change"?

 

Also, where do you get off slandering me then implying I can't respond?

 

"Science forums": *facepalm*

Edited by Over 9000
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In pretty much every post I define race by ancestry or genomic similarity. Sorry if you have a reading comprehension problem.

 

"If I was helpful, let me know by clicking the [+] sign ->"

 

Is there a [-] sign?

 

You can pretend I define race by "skin color" if you are unable to contradict me. If that makes you feel better.

If you define race in that manner humans do not have sub species... The genetic differences between humans is tiny and as I have said before humans are all members of the same gene pool. To call a subspecies there has to be some genetic isolation.

 

Wrong. Hybrids don't invalidate subspecies. "Race" is a word used to refer to infrasubspecific subspecies-(in the broad sense) among humans.

Who said anything about hybrids? You can't call hybrids unless you have genetic isolation...

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If you define race in that manner humans do not have sub species... The genetic differences between humans is tiny and as I have said before humans are all members of the same gene pool. To call a subspecies there has to be some genetic isolation.

 

Oh sorry you're confused. I defined race by ancestry (Darwin) or genomic similiarity (Mayr). You seem to be arguing against some imaginary indivdual who defined race as ancestry or genomic similiarity + some random arbitrary threshold based on nothing.

 

Have fun with that.

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All humans originated from Africa. Fact or no?

 

If all humans came from Africa, the first humans were Black. Fact or no?

 

Over 5 thousand years, is it possible people in Africa could have developed darker, "Black" skin?

If you answer these 3 questions they lay down a foundation for or against your argument.

1. "All humans originated from Africa....?"

Is really the only question that needs be answered. (for you and Moontanman)

YES!

Of Course, All Gorillas and Chimps not only originated in Africa, but are STILL there in a Small portion of Central West Africa.

And Gorillas have TWO separate SPECIES, and 6 or 7 subspecies/Races

Chimps have TWO separate SPECIES and 4 subspecies/Races.

So Chimps etc aren't "just chimps" either!

 

Range of ALL the different Gorillas AND Chimpanzee Species/Subspecies:

1_2.jpg

 

There is a complete and stunning Lack of knowledge/frame of reference for most here!

And I might add, the Human subspecies/Races were obviously subject to/Forced by much Greater selective pressures due to Much More Diverse environments those other two primates who are STILL just in a small jungled portion of Africa!

 

To even ask the question/pose the idea, one was to be Unaware that not only all chimps/gorillas have designation/delimitation, but virtually ALL other species have subspecies.

So it's a fast GAMEOVER (and free edu) for all of you that believe because we 'originated in Africa' we can't have subspecies!!!

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Edited by bering strait
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So it's now GAMEOVER for all of you that believe because we 'originated in Africa' we can't have subspecies!!!

 

 

Humans represent a recently derived species characterized by low genetic diversity, high gene flow and clinal variation. If you examined the genetic data, naive to the origin of the data I have no doubt that any competent population geneticist would define human populations as being divergent enough to warrant taxonomic description.

 

Chimp subspecies display orders of magnitude more divergence than human populations. http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.0030066

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Humans represent a recently derived species characterized by low genetic diversity, high gene flow and clinal variation. If you examined the genetic data, naive to the origin of the data I have no doubt that any competent population geneticist would define human populations as being divergent enough to warrant taxonomic description.

Chimp subspecies display orders of magnitude more divergence than human populations. http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.0030066

 

 

 

Bering Strait replies:

YOUR Link:

 

"...The most comprehensive study of chimpanzees to date—including multiple loci and samples from western, central, and eastern chimpanzees and bonobos—found few fixed genetic differences among chimpanzee populations and estimated autosomal FST values between populations of 0.09–0.32, Overlapping the range of differentiation seen in humans.".."

 

So your claim is a Complete MISrepresentation of the study and the Facts. We/Our subspecies have about the Same genetic distance as Chimps do!

Are there Sanctions for this kind of scandalous posting?

 

ANOTHER: (and also "Overlapping" with Chimps)

 

Is Homo sapiens polytypic?

Human taxonomic diversity and its implications

Michael A. Woodley

School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, UK

https://lesacreduprintemps19.files.w...plications.pdf

 

...Based on Table 2, it is evident that the ‘H. sapiens as monotypic species’ theory is INconsistent with the way in which taxonomic classification has been employed for other species exhibiting similar degrees of heterozygosity.

 

Chimpanzees for example exhibit very similar degrees of observed heterozygosity to humans (0.63–0.73 vs. 0.588–0.807) yet have been divided into Four subspecies.

 

Some species such as the grey wolf actually exhibit Lower levels of observed heterozygosity than humans (0.528 vs. 0.588– 0.807) yet have been divided into as many as 37 subspecies.

 

When measures of Genetic distance are used such as Wright’s FsT, which describes the fraction of the variation attributable to population subdivision, values indicative of Great Levels of Genetic Differentiation have been obtained for Humans (0.156) based on the analysis of autosomal loci [39] (great levels of genetic differentiation correspond to values of between 0.15 and 0.25 [40]).

This contrasts with scores indicative of little to moderate levels of genetic differentiation in other animals (again obtained by looking at autosomal loci), such as the Canadian lynx (0.033) [28], which is recognized as having three subspecies, and the African buffalo(0.059) [24], which is recognized as having five subspecies."..."

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and of course, NO ANSWER to the rest/essence of my post: Refutation of the common but Mind blowing proposition (from at least Two posters) that just because a specie 'originated' in a common place, it can't have subspecies!

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Edited by bering strait
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and of course, NO ANSWER to the rest/essence of my post: Refutation of the common but Mind blowing proposition (from at least Two posters) that just because a specie 'originated' in a common place, it can't have subspecies!

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Ok, your not using science, that's evident. So if we don't use science, then you yell at us, and when we say your not using science your basing your entire argument on the fact you refuse to answer:

"Stupid Posts"

So in this same manor, should we decide not to respond to your post in your opinion(We did) then its suddenly, YOU IGNORE ME UNDERLING!

"People who facepalm science forums" *facepalm*

 

Anyways:

So it's now GAMEOVER for all of you that believe because we 'originated in Africa' we can't have subspecies!!!

 

This is stupid. Quite literally. We evolved from Chimps, Apes, and Gorilla's. Meaning, they were here first. If they were here first then they have more time to evolve. And might I remind you, all humans are still inside the same gene pool. You can intermingle with anyone, anywhere, as long as they are physically healthy, and have a kid. With subspecies, you can't. So your basing your claim that the human sub species are not "100%" subspecies, yet your saying we are sub species entirely. There's a loop that never ends, and it doesn't prove anything to anyone standing out side of the loop.

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Ok, your not using science, that's evident. So if we don't use science, then you yell at us, and when we say your not using science your basing your entire argument on the fact you refuse to answer:

"Stupid Posts"

So in this same manor, should we decide not to respond to your post in your opinion(We did) then its suddenly, YOU IGNORE ME UNDERLING!

"People who facepalm science forums" *facepalm*

 

Anyways:

So it's now GAMEOVER for all of you that believe because we 'originated in Africa' we can't have subspecies!!!

 

This is stupid. Quite literally. We evolved from Chimps, Apes, and Gorilla's. Meaning, they were here first. If they were here first then they have more time to evolve. And might I remind you, all humans are still inside the same gene pool. You can intermingle with anyone, anywhere, as long as they are physically healthy, and have a kid. With subspecies, you can't. So your basing your claim that the human sub species are not "100%" subspecies, yet your saying we are sub species entirely. There's a loop that never ends, and it doesn't prove anything to anyone standing out side of the loop.

Just as a point of note, we didn't evolve from chimps, gorillas and other apes. All apes share a common ancestor with the various existing species diverging from each other at different times. Along our own line, humans and chimps were the last to diverge. Chimps further sub-divided. Humans did as well. However, the branches that could have been sub-species or even fully distinct species of human have all died off except for us.

 

Given enough time, our various geographic populations probably could have developed into new sub-species or even fully distinct species of human. However, in evolutionary terms, none of our populations were truly isolated for very long.

 

There has been constant gene flow between populations since humans started expanding, and the starting population wasn't particularly genetically diverse to begin with. It's likely that our population numbers had dropped to quite small numbers at various points in our past, so that by the time we migrated out of Africa, humans would have been comparatively quite inter-related for an entire species.

 

Less than 100,000 years later and we're unquestionably a single globe-spanning gene pool. With constant intermixing in the meantime, there simply hasn't been time for enough genetic diversity to build up in any population to allow for anything beyond fairly superficial diverge in outward features as a result of both adaptation to immediately local conditions and some founder effect from the specific features of whatever band of humans initially migrated into a given region.

 

So it's not that apes have been around longer than us. We're all derive from a single population that was around at the same time as itself and we've all had just as long to diverge as each other, especially us and chimps who split from each other last and have therefore had just as much time to diversify.

 

It's just that our more diverse branches all died and theirs didn't.

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Just as a point of note, we didn't evolve from chimps, gorillas and other apes. All apes share a common ancestor with the various existing species diverging from each other at different times. Along our own line, humans and chimps were the last to diverge. Chimps further sub-divided. Humans did as well. However, the branches that could have been sub-species or even fully distinct species of human have all died off except for us.

 

Given enough time, our various geographic populations probably could have developed into new sub-species or even fully distinct species of human. However, in evolutionary terms, none of our populations were truly isolated for very long.

 

There has been constant gene flow between populations since humans started expanding, and the starting population wasn't particularly genetically diverse to begin with. It's likely that our population numbers had dropped to quite small numbers at various points in our past, so that by the time we migrated out of Africa, humans would have been comparatively quite inter-related for an entire species.

 

Less than 100,000 years later and we're unquestionably a single globe-spanning gene pool. With constant intermixing in the meantime, there simply hasn't been time for enough genetic diversity to build up in any population to allow for anything beyond fairly superficial diverge in outward features as a result of both adaptation to immediately local conditions and some founder effect from the specific features of whatever band of humans initially migrated into a given region.

 

So it's not that apes have been around longer than us. We're all derive from a single population that was around at the same time as itself and we've all had just as long to diverge as each other, especially us and chimps who split from each other last and have therefore had just as much time to diversify.

 

It's just that our more diverse branches all died and theirs didn't.

True, my bad.

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Could migration be selective like natural selection is, where it is who migrates rather than who reproduces? The Founder effect can result in a radically transformed gene pool in a single generation. Migratory selection would not require long time spans like natural selection does, but only a highly selective filter. It could introduce extra variation between recently diverged gene pools that would be inconsistent with the recent-shared-ancestor approach.

 

I haven't read the full publication, but this abstract is what brought it to mind.

 

Why Are Immigrants' Incarceration Rates so Low? Evidence on Selective Immigration, Deterrence, and Deportation.

http://www.nber.org/papers/w13229

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