Human evolution and differentiation of races

[Earthborn]

much like finding an ambidextrous person does not rule out the fact that many pure lefties and pure righties exist.

Ridiculous example. Not many "pure" lefties or righties exist. Most people can use both hands just fine, and can learn to do most tasks that they would normally do with their preferred hand almost as well with their non-preferred hand.

 

[Kotatsu]

races exist, and yet there are no racial characteristics that are unique to one specific race.

there are Asians with African shaped noses and lips. there are Africans with blond hair.

there are Asians with white skin...and Europeans with black/brown eyes.

I don't see how any of those statements are relevant, as a given character could be characteristically shaped for several species, which differ in other characters. Your statements could easily be rewritten to :

There are populations in both Asia and Africa with noses of shape X and lips of shape Y
There are populations in both Africa and Europe with blond hair
There are populations in both Asia and Europe with white skin
There are populations both without and within Europe with black/brown eyes.

This could just mean that e.g., blond hair had evolved twice, which does not necessarily mean that the mutations behind that evolutionary step is homologous. For instance, blond hair in the African population could be due to a failure to produce a certain pigment, whereas that in European populations could be due to a failure to transport these pigments from their origin cells to the hair follicles.

No single character needs to be unique for something to be "permissible" as a new taxon, regardless of what that taxon is. It could as easily be a combination of characters, and this is indeed often the case. In your examples, the Asian population could be characterized by having X-shaped noses and Y-shaped lips, but also white skin. This combination is unique in the framework you have provided, even though none of the involved characters, on its own, are.

There is also no requirement that a taxon is defined by one character or a set of characters that are easy to see, or that they are non-overlapping. It might be that group X is separable from group Y mainly on geography, but also by the fact that the radius of the ulna in X is 59-63 mm, whereas that of group Y is 62-67, meaning that individuals measures in the home region of group X show a tendency to have more slender ulnas, whereas those from group Y's home region are more sturdy. Skin colour, hair colour, eye colour, and so on could be identical between the two groups, and -- depending on what group of organisms we are looking at -- this difference in ulna thickness and geographic range could still be sufficient to describe the two as two different taxa, even on the rank of species in some cases.

If you look at skin colour, you draw the line in one place, at hair, in another, at the shape of the eyes, in another, etc.
Which suggests that there is a real problem with the concept of distinct races.

Or that the characters used are not very useful, because the underlying difference is in other characters, such as skull shape or something.

By this twisted definition of species every human that can no longer reproduce becomes a new species.

That is a curious way of misunderstanding biological terminology. A population is not a snapshot, because then every breeding season would yield new species. If we say that the Corsican population of X has a longer beak than the mainland population, we do not mean it as a fashion statement -- "Beaks are long this year in Corsica, and it seems the bell-bottoms are back at last!" -- but as a character that is constant over a period of time which is at least equal to the average life span of a small number of generations.

Similarly, Soapy Sam's group does not collapse into smaller groups once one or more individuals cease to be able to reproduce, because he/she has been (1) actively reproducing with other members of the group prior to this change. To drive your objection to its logical, but inane, extreme, I am my own species because I am not actively interbreeding with anyone as I type this message. Over the next few years, I hope to be, however, and hopefully with something of my own species. Thus, I am (hopefully still...) actually viable with the human population in my surroundings.

So which race do these kids with their "easily recognizable characteristics" belong in?
Link to image.

How can you expect anyone to be able to tell from just a photo, and one of two juveniles at that?

Note also that Perpetual Student claimed that populations have "very distinct and easily recognizable characteristic". This does not imply that these characteristics are as clearly expressed in all individuals within these populations.

You have, in essence, given him/her a sample of two individuals, collected in an era where these characteristics are being blurred because of breeding across population lines for several generations, and expect him/her to accurately place them within a framework of populational averages, based on a small subset of characters taken from two juveniles which may or may not express the characteristics of the adults correctly. It can be very hard to distinguish species of different families based on such a strange sample, let alone some sub-subspecific variation within the same species. In short, you are being outrageously unfair, and try to characterize this as some sort of rhetorical point.

---
(1) Assuming the group does not include social recluses.

 

[bpesta22]

I'm purely left handed. Can't do anything well with my right hand. Doesn't mean I can't use my right hand, but the difference between left n right is huge for me. Plus handedness maps on to differences in brain structure-- I'm pretty sure it's biologically determined.

I agree handedness seems to be a continuum more than a dichotomy which is why I think it's an excellent analogy for those who claim "unless race is defined-now as a perfect biological dichotomy, it can't exist."

 

[lomiller]

The undeniable fact is that human populations exist with very distinct and easily recognizable characteristics although those characteristics may be tiny from the perspective of the genetics involved. Should these different populations be called races, population clusters, or some other polite term? It does not really matter; but whatever we call them, their existence cannot be denied!

The issue isn’t that such variation exist, it’s that they are being shoehorned to fix a preexisting definition even though the genes themselves start at a central location and radiate freely without respect to race. If you have interest in studying such a gene race is therefore a poor tool because it has only a passing connection.


Some interesting recent news.

It seems most European males may be descended from near east ancestors within the last 10 000 years.

http://www.sciencedaily.com/releases/2010/01/100119133508.htm

 

[Thunder]

Now, take 1,000 dark skinned Africans and bring them to say, Ohio. They can only breed with each other.

How many years would it take for these people to start having lighter skin, not through sexual selection, but through mutation and survival of the fittest?

 

[Madalch]

Now, take 1,000 dark skinned Africans and bring them to say, Ohio. They can only breed with each other.

How many years would it take for these people to start having lighter skin, not through sexual selection, but through mutation and survival of the fittest?

Take 1000 dice. Roll them once a day.

How many years will it take to get all ones?

 

[The Fallen Serpent]

I object to declaring words off-limits for the sake of political correctness.
On the other hand, using the term "race" in a scientific context is quite useless, as has been amply pointed out by others here.
English, like all languages, has many words that function well in the common language but have little use in a scientific context. Trying to limit their usage in the common language strikes me as useless snobbery.

I do not think anyone is declaring the word race off limit, more presenting the evidence why it does not hold up in biological science. That was what someone had questioned, race not being biologically held up. Race certainly has social implications. Race in terms of the US Consensus and similar projects tends to be regarded as an ethno-cultural self-identified label. I think this is the appropriate way to approach the subject of race.

 

[RecoveringYuppy]

How many years would it take for these people to start having lighter skin, not through sexual selection, but through mutation and survival of the fittest?

Are they allowed to drink Vitamin D fortified milk? That and a million other questions make it impossible to answer your question. BTW why rule out sexual selection? How would you prevent it? How is it not an example of fitness?

 

[bpesta22]

I do not think anyone is declaring the word race off limit, more presenting the evidence why it does not hold up in biological science. That was what someone had questioned, race not being biologically held up. Race certainly has social implications. Race in terms of the US Consensus and similar projects tends to be regarded as an ethno-cultural self-identified label. I think this is the appropriate way to approach the subject of race.

What bar do you use to establish that race has no biological meaning?

In other words, what's the burden of proof for one who claims it's possible that biological factors which co-vary (strongly but less than perfectly) with race as a social label might *partly* cause behavioral differences at the group level across these labels?

You might say the burden's on me, but I making the far weaker claim. That the biological effects are larger than zero and smaller than 100%. Anyone taking the extreme positions (0%, or 100%) would seem to have the burden? It's like saying all crows fly, versus most do, or some do.

***

Can race be a manifest indicator (e.g., skin color) for the latent construct (whatever it is biologically that distinguishes one race from another)?

I see this as *possible*, just like a series of 20 items measuring out-goingness is seen as a reasonable indicator of the construct, extroversion.

So, if we must throw out skin color as a biological measure-- to be consistent-- wouldn't we also need to throw out personality tests as a psychological measure?

 

[bpesta22]

Another thing people don't seem to consider-- imo-- is that things exist at different levels of categorization. This is well-studied in psychology:

A fruit,
An apple,
A Macintosh (sp?) apple.

Because a Macintosh apple is different from a red-delicious (?) apple in no way invalidates the superordinate level category, apple.

Because a north korean is not 100% like a south korean (don't know if this is true, using it for argument here) doesn't invalidate the superordinate level category, asian.

I also suppose it's possible to create an apple/pear hybrid. We could then show people pictures of it (though we'd have to cull these pictures and create a non-representative sample of the fruit world) and demand them to label it precisely as an apple or a pear, else admit that apple and pear have no meaning?

Could someone help me out here, if they see a flaw in the logic?

 

[Thunder]

Are they allowed to drink Vitamin D fortified milk? That and a million other questions make it impossible to answer your question. BTW why rule out sexual selection? How would you prevent it? How is it not an example of fitness?

because sexual election often times does not choose the most advantageous characteristics for the environment that is lived in.

if humans and other animals chose their mate PURELY by biological advantage, humans would be MUCH harrier

 

[The Fallen Serpent]

I posted some quotes above. Basically, the current conception of race completely failed to hold up to scientific scrutiny even a century ago, by those researching into eugenics and politically invested in supporting the concepts. If you change the meaning to encompass 30+ groupings, then you start coming up with something that might work. Otherwise the multitude of border groups confound the definitions, and taking into a account those border groups extends the border groups outward further confounding the divisions.

Take egyptians and nubians for instance. Nubians are considered black and egyptians are considered white even though they have been intermingling for thousands of years, being border populations with much interaction. If you then readjust egyptians to be black, then what about the ethnicities of the Levant? The local (as opposed to recent immigrant) jewish populations, the palestinians, the syriacs? Those groups have history and intermingling with Egypt as well. Add them then we need to consider kurds, arabs, turks... The problem never ends. Also I just overlooked a multitude of various ethnic groups in these areas for simplicity. Any point of division becomes arbitray in a biological sense, and only meaningful in a social context.

There is nothing wrong with race having multiple meanings. Yes, race does mean something specific in biological terms. Humans only have one in that regard. Race means something else in social terms. That has use in population studies and in social movements. Biologically, this social meaning of race completely fails to provide anything meaningful.

 

[The Fallen Serpent]

if humans and other animals chose their mate PURELY by biological advantage, humans would be MUCH harrier

...and I would get a lot more female attention. Or did you mean more like fictional wizards? I'm hairy not harry.

 

[Zelenius]

I posted some quotes above. Basically, the current conception of race completely failed to hold up to scientific scrutiny even a century ago, by those researching into eugenics and politically invested in supporting the concepts. If you change the meaning to encompass 30+ groupings, then you start coming up with something that might work. Otherwise the multitude of border groups confound the definitions, and taking into a account those border groups extends the border groups outward further confounding the divisions.

Take egyptians and nubians for instance. Nubians are considered black and egyptians are considered white even though they have been intermingling for thousands of years, being border populations with much interaction. If you then readjust egyptians to be black, then what about the ethnicities of the Levant? The local (as opposed to recent immigrant) jewish populations, the palestinians, the syriacs? Those groups have history and intermingling with Egypt as well. Add them then we need to consider kurds, arabs, turks... The problem never ends. Also I just overlooked a multitude of various ethnic groups in these areas for simplicity. Any point of division becomes arbitray in a biological sense, and only meaningful in a social context.

There is nothing wrong with race having multiple meanings. Yes, race does mean something specific in biological terms. Humans only have one in that regard. Race means something else in social terms. That has use in population studies and in social movements. Biologically, this social meaning of race completely fails to provide anything meaningful.

I agree with most of what you say. Race has always been a fuzzy concept; to pretend otherwise, well, I think people do this more for political reasons(create a ludicrous strawman definition of race and then refute it and voila - race doesn't exist!).

I've participated in discussions like this before here on JREF, and other boards and I always see the same strawmanisms, obfuscations, and overburdening of the concept of race all in an effort to make it seem biologically meaningless. I see the same old arguments in which race is conflated with species, as if races have to have fixed borders in order to be considered biologically meaningful. No one really doubts that species exist, but there is still some controversy about how to properly define it. There is still much controversy concerning the labeling of numerous animal and plant species, and whether a certain variety is truly a separate species or a race of a certain species. For all the confusion in say the proper classification of the different varieties of dandelion species and races, no botanist comes out and says "race doesn't exist".

 

[The Fallen Serpent]

Right, but race as defined in biology is a completely different animal than what people mean in regards to human races. Human races do exist. They are a social construct that vaguely takes into account skin color and possibly other traits. Biologically, when we try to put the social context of race into practice we come up with categorisation closer to what we mean with ethnicity. True that being difficult to define or create borders is not an insurmountable task for a category, but the human social concept of race is so vague and so arbitrary that any form of basis in biology it falls apart. That is what is different about the confusion about species compared to human races. The arguements over how to define species or which species is which is based in biological evidence. The arguements over how to define human races are based in social contexts or instead break down when biological evidence is used. Using biological evidence for human races turns into a huge number of categories that go against the initial intent of the broad based categories.

If people want to or try to use race with a more biological evidence perspective that is fine. Keep it clear what is meant because most people when they hear the word race in the context of humans are going to think of a half dozen categories that are more social constructs than anything else.

 

[Roboramma]

because sexual election often times does not choose the most advantageous characteristics for the environment that is lived in.

if humans and other animals chose their mate PURELY by biological advantage, humans would be MUCH harrier

Not necessarily. Lack of hair makes thermoregulation through sweating more viable, and as persistence hunters thermoregulation can be very important.

When you have access to clothes lack of hair is also good in that you can always put on more clothes, but you can take off your hair (well, you can shave it, but then you're back to being hairless).

Now, hairlessness may have evolved through sexual selection, but that doesn't preclude other factors.

 

[Roboramma]

Or that the characters used are not very useful, because the underlying difference is in other characters, such as skull shape or something.

Absolutely. I only said that it suggests that the concept isn't useful, not that it demonstrates such. But to show that it's useful we need to look for those real underlying differences, rather than pointing to the ones that simply don't work.

I'm somewhat torn on this issue, really. I find it likely that there are some meaningful differences between populations that had some degree of reproductive separation for several thousands-tens of thousands of years, mainly because, as was said at the beginning of the thread, such variations can arise quickly, and such superficial variations really don't amount to all that much genetically.

What I have a problem with is not the concept that such variation arose, but that it arose cleanly. As people in africa intrebred with each other, their genes migrated through the continent, and from there through the middle east into asia and europe, even when the people themselves didn't move far from home. I don't know the rate of that genetic transfer, but it seems obvious to me that it was happening. So whatever races we might like to define are not cleanly cut off from each other.
The fact that in the last centuries there has been more direct contact between peoples previously cut off from each other mixes things up much more.

Basically, I don't have a problem with someone talking about whiter skin evolving due to selection pressures imposed by vitamin D deficiency in higher latitudes, but to suggest that Europeans, for instance, are one race and Africans are another is, in my view, counter to the science.

 

[The Fallen Serpent]

From what I can see since semi-reliable seas boats there has been near constant cross pollination over the mediterranean. Which is why traditionally north africans have been considered white despite being darker skinned on average than the average european on the north shore, and until more recent movements north africans not as dark skinned as those further south. Mountain ranges seem to be more of a barrier than water short of oceans.

The smaller the size of the population being examined the easier it is to find physical and genetic traits that are defining of the populatons variation from other humans. Populations that do not interbreed with their neighbors tend to stand out. Inbreeding problems become more apparent and it is more difficult to survive disaster. The Samaritans are near extinct and their strict rules on women and conversion in general mean they are likely not to survive as a distinct culture. Thankfully we are getting their writings translated and the language itself documented.

The most studied and tracked trait that can divide human populations I am aware of is viral resistance. Some meaningful broad based divisions can actually be formed around that. It sounds like lactose intollerance and other allergies are also a meaningful trait to track. I suppose disease susceptibility in general. World transportation and the massive increase in cross cultural nookie has been quite useful in spreading disease resistance and weakness, it often being a give and take.

That is why it annoys me when religious folk blame eugenics and things like Naziism on evoluntionary theory (or Darwinism as they call it). Evolutionary studies as far back as Darwin indicate that diversity and interbreeding is great for suvival of a sexual species. Inbreeding and purity is a recipe for disaster. Rather than breeding a stronger species forcing extra internal battle leads to a greater likelihood of extinction by lowering variance and the possibility of an issue coming up that another sector of the species could handle or solve.

 

[Skeptic Ginger]

Their race is ambiguous. Is there really a point there? My wife and I have a red headed daughter and we both have dark hair. So, what does that have to do with this discussion?

The point is racial divisions are based on facades, not based on actual racial divisions.

 

[Skeptic Ginger]

...How can you expect anyone to be able to tell from just a photo, and one of two juveniles at that?

One of two juveniles? What are you talking about. These are two well known twins. Their birth was well publicized when it occurred.

The point is so called racial characteristics and divides are arbitrary and not based on good science. With good science, racial divides would be clearly visible within the human genome. They turn out not to be.