Researchers Say Human Brain is Still Evolving

Oleg Alexandrov writes "Two genes involved in determining the size of the human brain have undergone substantial evolution in the last 60,000 years, researchers say, suggesting that the brain is still undergoing rapid evolution. The discovery adds further weight to the view that human evolution is still a work in progress, since previous instances of recent genetic change have come to light in genes that defend against disease and confer the ability to digest milk in adulthood."

It's remarkable how wrong this is

[nokilli (759129)]

First off, it's hard to see *any* species as being in anything other than a state of evolution. To suggest otherwise implies a superficial understand of what evolution is about.

That being said, it's conceivable that we're at the point where the human brain is the exception to the above. After all, what has been the driving force behind the evolution of the brain? Big-brained people surviving and succeeding in reproduction where little-brained people fail.

This isn't really happening anymore. Yes, smart people still trump over stupid people in most aspects of life, but stupid people still reproduce. Civilization has removed the engine through which drives the evolution of the species.

I can't believe how often highly educated people will pontificate on this subject, and get it wrong. Yes, usually the media is to blame -- science reporting is notoriously bad -- but that does not appear to be the case here.

Ironic that they should be so wrong on this of all subjects.
--
You didn't know. [tinyurl.com]

Re:It's remarkable how wrong this is

[John Hawks (624818)]

Well, it sure might look that way, but these genes strongly suggest that something related to cognition was under strong selection throughout history.

One of the two genes, ASPM, appears to have come under selection only 5800 years ago; but it is now at around 20 percent, with a frequency of near 50 percent in some Near Eastern populations. Whatever this allele does, it had a selective advantage of more than 5 percent. They don't know it necessarily makes people smarter, but it's hard to think what else it might be.

That's really the neat part; that it shows that this idea of "survival of the dumbest" is apparently not what has been happening. Instead, there is every reason to think we have been getting smarter.

The submission doesn't mention the most problematic part: These alleles are high frequency in some populations, but absent or low frequency in others -- suggesting there may be adaptive differences in the brain among human populations. From my weblog post: [johnhawks.net]

Geneticists are increasingly finding genetic variants that affect behavior. Several of these variants are now known to vary in frequency in different human populations. These alleles are two; the 7r allele of the dopamine receptor D4 (DRD4) gene is another that influences ADD/ADHD susceptibility (Harpending and Cochran 2002). The selective structure underlying DRD4 variation may be frequency-dependent, with different alleles correlating with alternative behavioral strategies that pose greater or lesser advantages in some populations. It is not clear whether such a mechanism is true of ASPM and Microcephalin; the selected alleles have risen to such high frequencies in some populations that it seems they are not mere alternatives; they are unilaterally advantageous -- at least where they have become common already.

--John

Re:It's remarkable how wrong this is

[nokilli (759129)]

They don't know it necessarily makes people smarter, but it's hard to think what else it might be.

Deference to authority perhaps? The gene that enables groupthink, which, today seems to be sending us into the abyss but thousands of years ago meant the difference between one tribe surviving another?

The whole business with the alleles and DRD4, I don't know anything about that. I just found the way that the conclusion was stated here to be clumsy. Rather than talk about the brain still evolving, a more accurate headline might be "Path of human brain's evolution identified".

The coverage evolution has received of late has been spooky. I'm seeing all kinds of signs that the MSM is trying to accommodate "intelligent design", an agenda that is served by implying that human evolution was thought to have stopped somehow.

Now that I'm looking at it again, maybe it is another case of bad reporting.

I believe you missed the point of the grandparent

[thecampbeln (457432)]

For about the last 100 years(-ish, in the western world at least), the engine that drives the evolutionary process in the human population has been (all but) removed by way of social programs, improved medical techniques, invitro fertilization (natural selection... anyone?), you name it. That's not to say I'm advocating doing away with these things, but anything that allows for the production of offspring by individuals that otherwise would not have had the ability or made it to the age to reproduce *naturally*, is "dumbing down" our collective human gene pool.

If nature wouldn't have allowed certain individuals to reproduce, and yet modern medicine/technology/whatever have, their "faulty" genes are allowed to continue past their naturally selected "use by date", so to speak. How in the hell is this not a bad thing for the population as a whole? By definition, natural selection has been removed and therefore evolution has ceased. Sure, the population is "evolving" (read: reproducing) but with a near 100% reproduction rate amongst those individuals who *choose* to reproduce (again, no evolution here), it is not "evolving" in the Darwinian sense. Only those with severe medical or physical problems are no longer "able" to reproduce, but again this does not evolution make (IMHO).

Re:I believe you missed the point of the grandpare

[Ihlosi (895663)]

My definition of "fitness" is the ability to procreate without the help of technology - medical or otherwise (KY is, of course excluded).

In that case, your definition of "fitness" is obsolete. In fact, it has been obsolete since humanity started using tools. Had your definition of fitness not become obsolete that long ago, well, we wouldn't be having this discussion on the internet.

I am simply supporting the idea that evolution has, for all intents and purposes, stopped in the human population due to these factors.

No, it has not. First of all, evolution is _slow_ compared to human lifetimes. How can you tell that a process has completely stopped that has time constants in the thousands of years ?

Also, these factors did not stop evolution at all. They merely modified the criteria used in the selection process. A very common fallacy of "critics" of evolution is that the criteria for selection stay the same. If this were the case, well, where are the dinosaurs ? They were wiped off the planet by a change in the selection criteria which they suddenly did not fulfill anymore ... whoops.

Re:I believe you missed the point of the grandpare

[Ihlosi (895663)]

1) Exactly what human tools have been around since "that long ago" that help you sticking (or receiving) a penis in the vagina?

The tools that allow individuals to actually get that far along the way of reproduction.

Fire. Helps to avoid freezing off important parts during cold winter nights. Also helps to keep your offspring from freezing solid during those nights, and helps to keeps the tigers away that want to snack on you, your partner and your offspring.

Clothing. See above. Can also help to influence potential mating partner's preference towards the wearer.

Jewelry/other adornments. See latter point of clothing.

Weapons. See the part about tigers above. Also help to impress potential partners, keep rivals away and provide food to you, your partner and your offspring.

Blankets. Ever tried to have sex outside during the cold season without one ?

Houses. Better version of blankets for that purpose.

Reducing "fitness" to the short time from intercourse to conception is quite shortsighted (to the point of blindness). Whoever can reproduce and ensure the survival of the offspring is "fit". Regardless of the tools used in the process. If someone can't do this even with currently available tools, well, in that case they should come up with better tool or they'll end up "unfit".

Re:It's remarkable how wrong this is

[ShadyG (197269)]

Whatever this allele does, it had a selective advantage of more than 5 percent. They don't know it necessarily makes people smarter, but it's hard to think what else it might be.

That's because you don't have it.

Re:It's remarkable how wrong this is

[ShieldW0lf (601553)]

You're mistaken. When there is a threat, we mutate. That's what's happening now, we're mutating and developing a more diverse genetic base. When a really nasty disease comes along, that diverse genetic base gives us a wider range of options to fight it.

The genetic diversity we're accumulating will help ensure that when the inevitable "culling of the weak" comes in some form or another, there are a few people who are strong in the right sort of way to carry on.

Considering the intermixing between cultures that occurs in modern society, as a species we're better off with as much genetic diversity as we can get until we manage to get off planet and remove the risk of a single superbug wiping us all out.

By the way, you're sorely misguided about the whole "stupid people breeding out of control" issue too. The problem isn't the stupid people breeding too much, it's the so-called "smart" people not breeding enough. We're on our way to a societal collapse because of it.

I agree

[Ogemaniac (841129)]

You are absolutely right...smart people are not breeding enough in the first world. Birthrates are now below replacement levels in every advanced country, with the US being in the least-bad position. In other nations, such as Japan, the lack of children is becoming a serious political issue. It will eventually be a problem in the US as well.

In order to sustain our population (which seems a reasonable target) we need to have about 2.1 children per woman. In the US, lower class people are doing just about that. It is the top half of the income distribution that is failing to do its duty by replacing itself in the next generation.

I have seen some estimates that we could lose as much as one point of IQ per generation due to differential numbers of children and mother's age at birth - a pretty scary thought if you ask me.

Unless some amazing new technology comes to save the day, in the next few years we are seriously going to have to consider more government manipulation of birthrates, or our society and culture could disappear.

Re:I (don't) agree

[chuckT (12278)]

Is there not a major assumption being made here - that smart people are wealthier than poor people?

I think of myself as pretty smart, but I know a lot of dumb people who earn more than I do. Wealth (and by implication survival in the modern world - although that is another questionable assumption) is far more a matter of luck and inheritance (wealth or status, not genes) than intelligence.

In fact, I suspect that there are far more important qualities, relating to the ability to focus on specific activities or goals that are relevant to an individuals wealth generating ability.

In any event, I would completely reject your implication that we kill off the poor because they are polluting the human gene pool. Your argument is based on false assumptions, could itself potentially remove useful variety from the gene pool, and goes against every compassionate human instinct I possess.

I don't like it.

Sorry.

At this point, I think we should invoke Godwin's law [wikipedia.org], and shut up.

Re:It's remarkable how wrong this is

[abandonment (739466)]

I hardly consider modern society as a 'normal' state of evolution.

Whether you have more money or not has absolutely nothing to do with whether your 'genes' are hardy enough to survive, propogate and evolve.

The state of modern society has in fact thrown out thousands of years of evolution in favour of 'creationism', and the 'golden law' - ie those with the most toys wins.

This has nothing to do with evolution, it has everything to do with the rich feeding the rich and the rich doing everything in their power to stay rich.

Look at how much 'old money' runs the world (in the US and abroad). You think that these same people, if given the same upbringing, financial situation and social status (ie 'socialist states') are somehow 'better' than those raised in capitalist 'everyone for themselves' environments?

I hardly think so.

The Bush family dynasty is the prime example of how this theory fails miserably.

When you have generation after generation of idiot propogating and continuing their 'dynasty', you inevitably result in the idiots rising to the top - hence gwb II 'the sequel' - and the rest of the old money families that think they know best and flounder around trying to play 'risk' and destroy the world...

Re:It's remarkable how wrong this is

[justin12345 (846440)]

Socialism has nothing to do with it.

I live in Brooklyn, and a nasty part of it none the less. Long story as to why I moved here...

I'm not too worried about survival (I'll be leaving this winter; moving into a .5 million dollar home in Baltimore. Plus, NYC has a very low murder rate compared to most American cites.)...

Still as far as selection goes, my neighbor is clearly the victor. Ultimately his family will in the long term have a much greater chance of survival then mine, based on shear numbers alone. He works as a janitor (kinda), makes maybe 25k-30k, but has 9 kids by three different women (8 really, the 9th is expected in December). I OTOH have none (granted he is 4 years older then me... he is 29 and unmarried, had his first child at the age of 17).

Chances are, most if not all of his children will survive to reproductive age. Its also likely that few will attend college (though this really is speculative, I'm just basing it off of the fact none of their parents or grand-parents did, AFAIK).

Chances are that I will have few or no children: My girlfriend is on the pill and another prescription medication which further limits her fertility because it would require an abortion if she were to become pregnant within a year of taking it (the medication causes severe birth defects).

Even if we do wind up reproducing, I really doubt I will have more then 2 or 3 children. My neighbor OTOH, whom definitely has a lower quality education (intelligence is too subjective to judge) has definitely been far more prolific then I will ever be, though I had and probably will have a far greater quality of life.

Ironically, because we have access to excellent health care (much more so then my neighbor) we are able to choose sterility. That is not the case for my neighbor, whom cannot/will-not control reproduction (as he has complained in his own words during our infrequent conversations).

There is no welfare involved here. All parents mentioned here work and support themselves and their children (to the best of my knowledge).

* puke *

[ThinWhiteDuke (464916)]

I agree. This whole civilization thing is way overrated. The mere concept of helping each other for no immediate personal profit reeks of communism. Let's abolish all of this crap and adopt an efficient win-or-die model. Well, the wolves have been doing this for eons, and they are obviously a much better evolutionary success than us humans.

Look, what you wrote is wrong on so many ways... Factually, morally, economically, you name it. People like you consider that misery is a feature of the system rather than a bug. You have wilfully renounced what has always driven human development.

You, sir, are evil.

Re:It's remarkable how wrong this is

[Cruithne (658153)]

The solution to this problem is obvious.... only let the people with an IQ above X have sex :D

If you mod me down or reply negatively, you lose sex priveledges too :D

Re:It's remarkable how wrong this is

[Tony Hoyle (11698)]

If I was world dictator I'd have enforced sterilisation at birth and parent licenses allocated after rigorous testing.

That's probably why I should never be allowed any power...

Re:It's remarkable how wrong this is

[magarity (164372)]

there ought to be some standard for parenthood
 
While I'm glad I'm an Alpha, I clearly see the need for Gammas and Deltas. And for them to be in greater numbers than the Alphas and Betas. That reminds me; trash truck comes tomorrow AM...

Re:It's remarkable how wrong this is

[JeffSh (71237)]

Eugenics was only a single generation (or perhaps 2 generations) of testing. breeding favorable traits (or any trait) requires many many generations.

to see this, just look at dog breeds.

the same could easily be done with humans, certainly.

Re:It's remarkable how wrong this is

[Cruithne (658153)]

"An athlete and a model, seemingly superior breeding stock, frequently have children with horrible birth defects."

I like how that's totally a fact you can back up with data from the local library's copy of "kids of athletes and models - 2005 edition".

But seriously, although eugenics does not sit well with me or anyone most likely, and while your logic is correct - two idiots can breed a genius, I would wager statistics would prove that people with higher educations breed people who contribute more to society, and it probably helps to be more "well off", too.

Before I get flamed to death, I am definitely not advocating birth control in this sense (or eugenics) - the key is in the education, which brings with it the wealth.

To me its always been a shame that one of the most promising tools for improving society gets the shaft over and over again... Not to get offtopic, but its a shame that probably more than half the teachers in our institutions should not be teachers, and that the ones who should teach out of a desire to teach and make a difference (rather than for the small compensation) - most everyone has that really good teacher they remember that really made a difference.

To be a teacher should require as much education as it does to become a Doctor - possibly more, and they should be paid more, too. The day we see that is the day we see some real advances in society.

Re:It's remarkable how wrong this is

[aussie_a (778472)]

An athlete and a model, seemingly superior breeding stock, frequently have children with horrible birth defects.

Which goes to show they aren't superior breeding stock. It was probably the bulemia and drugs that caused the problems.

Hoist by your own petard

[exp(pi*sqrt(163)) (613870)]

You're as wrong as the people you criticize

Civilization has removed the engine through which drives the evolution of the species.

What engine has been removed? There is still a differential rate of reproduction between different groups and so natural selection is carrying on exactly like it has always done. You say the engine has been removed because you have a preconceived notion that certain traits should be selected for (eg. not being stupid) and when you see that those are not the traits associated with a higher differential rate of reproduction you dismiss it as not being evolution. Sometimes I wonder if anyone out there has actually bothered to try understanding evolution.

Re:Hoist by your own petard

[AJWM (19027)]

Natural selection must not only mean that the possession of some combination of attributes confers both survival and the opportunity to procreate, the absence of those attributes must mean the opposite.

No, it's virtually never that clear cut. There'll be some attribute(s) that confer a marginal increase or decrease in the likelihood of individuals to reproduce, or not. It's not all or nothing. Over a hundred generations, though, even a 1% marginal difference adds up to a significant population shift.

Re:It's remarkable how wrong this is

[MyLongNickName (822545)]

while others will be smart enough to keep their beliefs to themselves.

What is funny is you don't realize you just put yourself down.

Duh?

[Dimensio (311070)]

Evolution is not attempting to attain a certain "goal" at which it stops. Evolution is simply the result of certain genetic traits being selected based upon environmental pressures. It shouldn't be too surprising that evolution still occurs in humans so long as there is a situation where some genetic traits are more likely to be passed on through reproduction than others.

I guess this could be news to people who don't actually understand evolution -- which, given the popularity of pseudoscience like "Intelligent Design" and non-science like "Creation Science" -- probably is quite a bit. Unfortunately, experience shows that they don't really care to learn anything about evolution anyway, so chances are they'll do little but mock the findings without even trying to understand them.

Learn the nature of science.

[Dimensio (311070)]

Now that is a loaded statement.

No, it isn't.

Evolution is nothing but a theory.

Creationists say this like it means that it's somehow on shaky ground. It isn't. "Theory" is the highest level that any explanation reaches in science. There is no higher label. The dismissing of evolution as "nothing but a theory" only demonstrates that the one making the dismissal is fundamentally ignorant of scientific terminology.

Ask any REAL biologist (like those with Ph.D.'s or those who work in colleges), and they will admit evolution is a theory.

And theories never get any higher in rank.

It is not fact.

"Facts" are simply statements about single observations, nothing more. "Facts" really don't mean anything in the long run in science.

It is not a scientific law.

And it never will be. Despite the ignorant rantings of creationists, theories do not ever become laws. Theories and laws are two different types of statements. Laws are general statements about collections of previous observations by which future observations are predicted. Theories are an attempt to explain the underlying causes of the observation. Example: the "Law of gravity" is a model of the resultant force caused by gravitational attraction between two masses. The theory of gravity -- more commonly known as "relativity theory" -- is an attempt to explain why that force occurs.

Laws are no more certain than theories. Theores do not "graduate" into laws. Laws can just as easily be falsified -- in fact, the "Law of Gravity" as we know it from Newton is false. Saying that "evolution is a theory, not a law" as if this casts some doubt on the validity of evolution again only demonstrates that you are fundamentally ignorant of how science works.

The cool thing Intelligent Design is we know God made us.

No, Intelligent Design postulates -- based upon faulty premises -- that certain features in biological systems are too "complex" to have come about through evolution, and therefore must have been "designed" by some unnamed designer. "God" doesn't enter into "Intelligent Design" as it is presented by the shysters who try to shove it into school cirriculums.

That you think that it directly refers to a god -- especially the God that you happen to worship -- only further demonstrates that ID is nothing but a sham to try to sneak religion into schools.

As for "know", I'm sorry but claiming that you "know" something isn't valid justification for scientific consideration. If you have no evidence, then you have no case.

Think about how the world was made. Science has a theory called "Big Bang". It is a theory which states that in the start the mass was so dense, it exploded and everything flew away randomly, making stars and planets, and life.

The Big Bang doesn't cover abiogenesis. Please actually learn the science behind it before attempting to discuss it.

For any people who know statistics, what is the probability of that happening? How many times would I have to flip a quarter and get heads in a row? 100,000,000,000 times? 100,000,000,000,000 times?

You know the statistical likelyhood? Please present the math. Show all of your work. If you can't then you don't have a case. Please avoid the fallacy of pointing to the "likelyhood" of the universe appearing in its exact configuration as it is and pretending that the universe couldn't have just as easily supported life had it come about in a somewhat different configuration unless you can demonstrate that it is the case.

You would have a better chance at taking a watch, hitting it with a hammer until it was broken into 1000 peices, and then putting it in a bag, shaking the bag, and having the watch come back together out of the random movements.

False analogy, demonstrating a fundamental ignorance of cosmology. Try to understand why physicists say what they say about universal origins before thinking that

Re:Learn the nature of science.

[Dimensio (311070)]

Now, since we don't have a time machine, we CANNOT falsify historical evolution.

But we can. Find a series of precambrian rabbit fossils, and everything we've constructed regarding the history of life comes tumbling down. A transposon found in whales and cows but not in hippos? That's a real problem with the way things are set up now.

Re:Learn the nature of science.

[Decaff (42676)]

Now, since we don't have a time machine, we CANNOT falsify historical evolution. It's just a theory, and absent a time machine we won't ever be able to test it.

Of course you can test it. You can make predictions about the way things could have evolved and what intermediate forms may have been present. You can then look for such forms in fossils. For example, there have been several theories about the lineage of whales, and fossil finds have helped test these theories.

In this sense evolution is a lot like cosmology. We can't go back to the early stages of the universe, but we can predict what should be there then look at distant (effectively 'fossil') light with telescopes.

Re:Theory or God??

[Wavicle (181176)]

evolution is a theory. It is not fact. It is not a scientific law.

Theory and fact are not exclusive. Stating something is a theory and is not a fact implies that the theory is wrong. Scientific laws are just "convenience" wrappers for theories. The things we call "laws" are theories just the same. They are still subject to the same rigor as theory.

The cool thing Intelligent Design is we know God made us.

And that is why you are NOT a science. Because you "know." You've moved from theory to statement of fact.

For any people who know statistics, what is the probability of that happening?

The probability of the event cannot be determined because we lack understanding of the state space.

How many times would I have to flip a quarter and get heads in a row? 100,000,000,000 times? 100,000,000,000,000 times?

The probability of getting N heads in a row is 1/(2^N). But that is irrelevant to the discussion.

You would have a better chance at taking a watch, hitting it with a hammer until it was broken into 1000 peices, and then putting it in a bag, shaking the bag, and having the watch come back together out of the random movements.

And you've calculated the probability of this how?

God made life. It is called a soul.

That it is incorrect. Life was bestowed upon the earth when the Flying Spaghetti Monster extended His noodly appendage and brought forth a midget in full pirate regalia.

Re:Theory or God??

[JanneM (7445)]

given the popularity of pseudoscience like "Intelligent Design"

Now that is a loaded statement.

Yes it is.

It doesn't go nearly far enough.

"Pseudoscience" implies that its proponents, cranky or not, at least sincerely believes in it. That is too charitable for "intelligent design".

"intelligent design" is a meticulously planned, focus-group designed, carefully executed fraud.

It is created only to deceive. It's intended purpose is not to explain anything, but only to diminish the public credibility of any real scientific explanatory model of life or the origin of our world.

Re:Theory or God??

[zpok (604055)]

[quote]
"intelligent design" is a meticulously planned, focus-group designed, carefully executed fraud.

It is created only to deceive. It's intended purpose is not to explain anything, but only to diminish the public credibility of any real scientific explanatory model of life or the origin of our world.
[/quote]

OK, broadly the same could be said about religion in general and most political statements.

But that doesn't mean people don't BELIEVE it.

My sister just can't believe we're somehow sharing traits with apes, while to me that's maybe our most redeeming quality ;-)

Re:Theory or God??

[Dimensio (311070)]

So you say that for anyone to have a discussion of evolution they must use your conventions of naming? I say bullshit.

And I say that if you're going to use the term "theory" to mean something other than what scientists mean and then claim that the theory of evolution is on shaky grounds because it is a "theory" by your definition then you're not arguing based upon facts, but upon dishonest semantics.

Which isn't surprising. I've observed that creationists are, in general, shameless liars. You're either one of them, or you're trolling. Your posts are more over the top than most creationists, but I do know that people have seriously expressed the insane and willfully ignorant sentiments that you preach in all seriousness, so it's hard to tell.

Counter-evidence...

[FyRE666 (263011)]

Researchers Say Human Brain is Still Evolving

I guess these guys have never browsed Slashdot at -1 then... And how do they explain George Bush, Beanie Babies and the Crazy Frog? And where did they get a 60,000 year old brain from to find these genes - Joan Rivers' skull? No no no, none of this is adding up...

Re:Counter-evidence...

[Tim (686)]

And how do they explain George Bush, Beanie Babies and the Crazy Frog?

Evolution optimizes for survival, nothing else. And unfortunately, in this country, there is a strong selective pressure against intelligence.

Sarcasm and "bling" on the other hand....

The human brain...

[myowntrueself (607117)]

is an organ for cooling the blood.

We actually think with our stomachs.

Obviously the cooling needs of the human body are still increasing over time. Probably linked to global warming.

Re:The human brain...

[Jace of Fuse! (72042)]

We actually think with our stomachs.

Nope. Getting warm though. Little lower...

Now, wait a second...

[rasafras (637995)]

The world has changed a lot, and I mean a lot, in the past millenium (even 2-300 years). The selective pressures that were around previously, causing the stupid to die, are no longer present. In fact, there is very little selective pressure in today's society, where the number of offspring you have is rarely related to prosperity or the like. The death rate is so low that I can hardly imagine selective forces having a large effect on evolution. Random mutation still occurs, of course, and perhaps over the next millenium one society will evolve to be smarter and will destroy the other with superior technology, but I seriously doubt this. I'm one of those people that considers human evolution to be nearly frozen. Soon to be supplanted by willful manipulation, of course (ethics debate about this some other time).

Re:Now, wait a second...

[Nefarious Wheel (628136)]

It's very clear that we're selecting for the ability to produce money, read the correct magazines, and our inability to spot prophylactics in the wild. And drive cars with large integral flat surfaces.

Re:Now, wait a second...

[craXORjack (726120)]

In fact, there is very little selective pressure in today's society, where the number of offspring you have is rarely related to prosperity or the like.

While I agree that human engineering will likely eclipse natural selection in the near future, I have to say that from my observations, at least of modern industrialized society, that the number of offspring is still related to prosperity. However the relation is probably backward from what you were thinking. It seems that the poorest (and least educated so maybe that is the deciding factor) members of our society are the ones having children at the youngest ages and having more children over their lifetime.

Gene distribution

[Fox_1 (128616)]

Dr. Lahn said there may be a dozen or so genes that affect the size of the brain, each making a small difference yet one that can be acted on by natural selection. "It's likely that different populations would have a different make-up of these genes, so it may all come out in the wash," he said. In other words, East Asians and Africans probably have other brain enhancing alleles, not yet discovered, that have spread to high frequency in their populations.

Another geneticist, David Goldstein of Duke University, said the new results were interesting but that "it is a real stretch to argue for example that microcephalin is under selection and that that selection must be related to brain size or cognitive function."

Basically this study shows that the 2 genes they studied are distributed with different frequencies in different populations, but occur more often in these populations now then 60,000 years ago. Anything else is just theory and speculation.

Re:Gene distribution

[Michael Woodhams (112247)]

There are statistical tests for the "under selection" part. here's [wsu.edu] the first summary I found. It changes the frequencies of nearby neutral mutations which get to "ride the coat-tails" of the advantageous mutation.

The "related to brain size/function" is somewhat speculative, in that the gene could have additional unknown functions.

That the mutation makes us smarter is much more speculative. (Indeed, I don't think the paper's authors went this far.) It could, for example, make us 0.1% less smart, but reduce the brain's metabolic cost by 0.5%.

(Note: I've only read the linked article, not the scientific paper.)

Depends on how much spaghetti you eat

[ScentCone (795499)]

Also, I understand that if you wear an eyepatch [venganza.org], that strengthens the optic nerve on one side of your brain. It is proof of His Noodly Will.

Stands to reason

[Bogtha (906264)]

Society has changed immensely over the past few thousand years. Evolutionary pressure has changed because the skills required to reproduce successfully are different. Being a good hunter is no longer a core skill. Being able to read and write is.

I wonder to what extent the difference in population growth for various countries will influence this. At the moment, first-world countries have much lower reproductive rates than third-world countries, but if the HIV epidemic continues, that situation could reverse itself.

When I gaze into my fishtank...

[randumspin (902235)]

Creatures from Another world? The past? The present?

Why yes. Take a look over there. Its the horseshoe crab, one of natures "living fossils". Even if you don't have a saltwater reef aquarium, you may notices roaches in your friends apartment...perhaps a sign that he doesn't clean up well enough or perhaps a sign that life will persist.

Evolution occurs as long as it is beneficial, to the organism in question or to its general environment. The oceans haven't presented enough of a change from way back when for the horseshoe crab and many other species to modify its design. Similarly, cockroaches are pretty good at finding corners and crevices to hide in and scavange, thus they have not needed change their modus operandi or physical design.

Humans are in an entirely different environment. In fact it is said that we are the only species which controls and modifies their environment. As such, it is a natural conclusion that as long as the environment and conditions are variable, evolution will continue to progress...always looking for that perfect design for life that maximizes its ability to persist.

Will this result in evolution or branching?

[tji (74570)]

As others mentioned, half of the evolution process is missing.. there is no selection of better traits. Everyone lives, thrives, and reproduces regardless of their genetic adaptations (or quality).

So, we still have the genetic randomization going on, resulting in differences in humans. But, then what happens? All the strains of humans just keep going.

Does this result in the spectrum of humans spreading increasingly wider, so eventually subjects at two extremes barely resemble the same species?

Will any noticeable branching happen? In previous evolution, one group survived and thrived, replacing members without an adaptation. Now, since the others still survive, and the difference between the weak and strong won't result in a dramatic difference in results for either group. Probably not anything recognizable outside the normal differences between tall & short, thin & fat, smart & dumb.

I've often wondered...

[M3number3 (814865)]

What exactly the role of modern medicine and civilization will eventually have on the overall evolution humans. Others have speculated about aspects of this, but my curiosity revolves around whether or not we (as a species) are preventing our own evolution by treating genetic diseases. Evolution is always triggered by a genetic change - with changes which make the species stronger carrying on and those which weaken the species eventually being eliminated. So what happens when a child is born with a genetic "defect" which, for lack of a better term, we simply don't understand. Do we treat that child, do we actively affect his/her ability to develop and thus prevent the eventual forking of the human species? This is somewhat thought provoking because I don't think any of us are smart enough to know the answer. The flip side of this argument, of course, is what to do when we are able to purposely engineer a superior branch of the human species. I'm not talking about changing eye or hair color, but rather our ability to create a "super human". Lastly, many folks believe that while human evolution may have slowed, it will likely make its presence known in a more significant way once we establish colonies in space. Imagine not the 1st or 2nd generations conceived and born in zero or reduced gravity (such as that in a space station, deep space craft, or even on Mars), but rather the 100th or even 1000th generation. Surely at some point these "humans" will have evovled traits which enhance their ability to survive and thrive in this new environment. Interesting stuff for sure.

Re:Can someone explain...

[ozmanjusri (601766)]

what is significant about the ability to drink milk during adulthood?

Most of the world's population can't digest lactose (milk sugar) after the age of about 4. The ability to digest lactose appears to have evolved along with dairy farming. Those parts of the world which did not practice dairy farming remain lactose intolerant.
http://www.scienceinafrica.co.za/2002/june/lactose .htm [scienceinafrica.co.za]

Re:Obviously

[MikeFM (12491)]

There has never been any reason to think that just because a trait evolves into much of the population that it will reach all of the population. Your videos are probably of the population missing these, and other genes, that increase mental ability.

The intelligent are now protecting the stupid in much the same way mankind has protected cattle. The stupid tend to breed with other stupid while the intelligent tend to breed with other intelligent people. At some point this should lead to a split in the species as the two groups evolve in different directions. Still it'd take quite a change to make the two groups incompatible for mating so you'll likely see the occasional mix.

Stupid people tend to breed faster than intelligent people but they also tend to live less healthy lifes which probably increases their mortality rate. I'd still imagine stupid people produce more children that live long enough to themselves reproduce than intelligent people though. To bad this topic is taboo because it'd be pretty interesting to study.

In the meantime - geeks unite and breed! Don't let the moron inherit the Earth! The fewer children you have the more likely they'll be wage slaves to stupid people. Fight back - have sex (with yourself doesn't count)!

This isn't stopping evolution...

[Dimensio (311070)]

...this is just changing the selection pressures. Ultimately, advances in medical technology alter the environment in such a way that it is less hostile to the reprodutive success to a given genetic range.

Missing acidolphilis and other friendly bacteria

[rufusdufus (450462)]

It is highly likely that what you actually experienced was missing "friendly bacteria" or pro-biotics that help humans digest milk. Milk products usually contain a these in small amounts; this explains why you were able to digest milk again after consuming it for a while, you had built up good colonies in your digestive tract.
Lots of people have stomach, mouth, and fungus problems of various natures which they try to treat with symptoms with pepto-bismal and other over the counter drugs when they would do much better to go out an eat yogurt every day for a week. Yogurt is high in friendly bacteria and will fix many symptoms you may have had for years.
One big cause of losing your friendly bacteria is taking anti-biotics. Some people take anti-biotics and struggle with intestinal and fungus problems for years because their friendlies have been wiped out by the anti-biotics. Doctors rarely prescribe yogurt with anti-biotic, but next time ask your doctor if taking pro-biotics is a good idea, and he will probably say yes. Why they don't bring it up on thier own has always been a mystery to me.

Re:Interesting

[king-manic (409855)]

I wonder how long it would take us to devolve via natural selection. Since there is an inverse relationship between education level and child rearing, then if one assumes more intelligent people tend to have higher educations and that higher intelligence when breeding contributes to intellectual evolution, then we may well be devolving because stupid people disproportionately reproduce. Of course, we'll probably genetically engineer our own brainpower up before too long, and solve that problem while opening up a whole new can of worms.

This is untrue, more intelligent people have fewer children, but these children almost always survive to reproductive age. It's simply a diffeerent strategy. one economic echulon (my spelling sucks) goes for a many children, few survivors method. whiel another goes for few children, but immense resources put into each.

LSD is NOT a mutagen/teratogen...

[Ellis D. Tripp (755736)]

Regardless of what they might spew in DARE classes...

http://www.erowid.org/chemicals/lsd/lsd_writings4. shtml [erowid.org]
http://www.straightdope.com/classics/a2_229.html [straightdope.com]
http://www.levity.com/aciddreams/samples/chromosom e.html [levity.com]
http://www.serendipity.li/dmt/chromosomes.htm [serendipity.li]