Are Humans Evolving Faster? (LC related)

[kyrasdad]

Are Humans Evolving Faster? (http://duggmirror.com/general_sciences/Are_Humans_Evolving_Faster/)

I'm not going to paste the entire thing, but here's a paragraph that bears pasting:
...Harpending believes the speedup in human evolution "is a temporary state of affairs because of our new environments since the dispersal of modern humans 40,000 years ago and especially since the invention of agriculture 12,000 years ago. That changed our diet and changed our social systems. If you suddenly take hunter-gatherers and give them a diet of corn, they frequently get diabetes. We're still adapting to that. Several new genes we see spreading through the population are involved with helping us prosper with high-carbohydrate diet."
So we have to mutate to thrive on the diet the AMA and the USDA want us to eat?

[JL53563]

Here's how I see this playing out a few thousand years down the road: Humans finally do adapt to eating lots of carbs. But by this time, alot of people have adopted the low carb way of eating. But since we have finally adapted to carbs, the carb eaters are healthier. So Dean Ornish's great, great, great..................great grandson says, "See, Dean was right. Carbs are good, and fat is bad." :lol:

[eryalen]

Are Humans Evolving Faster? (http://duggmirror.com/general_sciences/Are_Humans_Evolving_Faster/)

I'm not going to paste the entire thing, but here's a paragraph that bears pasting:

So we have to mutate to thrive on the diet the AMA and the USDA want us to eat?
The Bubonic plague caused mankind to evolve very quickly to resist that disease by killing everyone that was not resistant. Evolution does not select anything that benefits you after your fertile years (for men) or nurturing years (for women). In fact, it's best if you die immediately thereafter and not deplete the food supply. I'm sure that the bureaucrats would like you to expire on your first day of retirement and so preserve social assistance funds for them.

[Nancy LC]

I don't know if we'd evolve to handle carbohydrates, they usually kill us long after our reproductive years.

[KvonM]

The Bubonic plague caused mankind to evolve very quickly to resist that disease by killing everyone that was not resistant. Evolution does not select anything that benefits you after your fertile years (for men) or nurturing years (for women). In fact, it's best if you die immediately thereafter and not deplete the food supply. I'm sure that the bureaucrats would like you to expire on your first day of retirement and so preserve social assistance funds for them.
*blink* huh? ok i'm usually a smart girl, but you lost me on this one.

evolution works over time. it's a process by which a population of organisms adapts through genetic selection (sexual reproduction) in order to survive changes in the environment. since diseases like bubonic plague hit quickly, there isn't time for successive generations to selectively breed to favor resistance. people who survived the plague weren't necessarily resistant, they could have just been lucky. i do know there is a village in england that was indeed shown to be genetically resistant to the plague, but that was based on luck of breeding... prior to the outbreak, nobody would have known they were resistant.

any evolutionary changes that are going to take place are going to do so at or just before conception... meaning, females choose mates based on how well they thrive within a given environment (survival of the fittest). once they've chosen their mate and given birth to the next generation, the pattern is locked in place until that generation matures and reproduces.

nancy's right... if we lack the biological capability to effectively process large quantities of carbohydrates, by the time we reproduce, the damage is already done.

So we have to mutate to thrive on the diet the AMA and the USDA want us to eat?
pretty much, yeah. you'd have to have a population where the parents are unable to process high-carb diets, and an acceptable percentage of the offspring mutate with the ability to thrive on carbohydrates, and be able to pass on that mutation. two problems with that, though... the high-carb/low-fat dogma has only been pushed for the last 35 years (or a little more than 1.5 generations... a blink of an eye in evolutionary terms), and the liklihood of that happening is statistically nil in comparison to simply educating the general existing population that fat and protein are good, carbs are bad (m'kay).

the only thing you can count on evolution to do is attempt to guarantee the survival of the next generation. the solutions aren't always the best ones, nor are they the most efficient ones, but jury-rigged or not they still usually tend to work. except just like disease, misinformation can do far more damage to the population in such a short time frame that evolution can't keep up.

[bsheets]

Ok I know I should know this, but I've drawn a complete blank. Why do Chinese survive on tons of rice and italians survive on lots of pasta and Mexicans on corn and Irish on potatoes and English on bread (though bread didn't used to be quite as refined back then).... ? Or is the article saying all that only happened in the last 12,000 years (when agriculture took its greatest effect) and that isn't long enough?

I can understand that I don't survive well on carbs, my family history didn't each much carbs, but the whole human population?!

I'm totally confuzzled :P

e

[Nancy LC]

There's slow selection and there's quick selection. Something like the plague would quickly weed out people with genetic variations that make them susceptible. It isn't just luck. Something that killed 3/4ths of the population might have been a rare gene would then become quite common very quickly.

http://www.thetech.org/genetics/ask.php?id=10

But I don't think that applies in this case. You need people to die out quickly and carbs only kill you when you're pretty old.

[Elihnig]

Check out articles from the Weston A Price foundation.

http://www.westonaprice.org/traditional_diets/index.html

[KvonM]

Ok I know I should know this, but I've drawn a complete blank. Why do Chinese survive on tons of rice and italians survive on lots of pasta and Mexicans on corn and Irish on potatoes and English on bread (though bread didn't used to be quite as refined back then).... ? Or is the article saying all that only happened in the last 12,000 years (when agriculture took its greatest effect) and that isn't long enough?
probably because the makeup of those diets, historically speaking, is much different than the makeup of the 20th century human diet. it's already been shown that when other cultures adopt an american-style diet, they very quickly have increased rates of obesity, diabetes, etc.

italians also don't eat nearly as much pasta as we think they do. pasta is an accompaniment to fresh veggies and meats, not the main course that we make it out to be.

you're also talking about 12,000 years in the face of 1.5 million or more. so for about 99% of our existence, we've been functioning on fats and proteins with minimal carbohydrates. it's only the last 1% of our history that carbs have been readily available, only 0.1% of our history that they've been processed in the form we use today, and 0.025% of our history that we've insisted that carbs are the most important part of our diets.

[ojoj]

Ok I know I should know this, but I've drawn a complete blank. Why do Chinese survive on tons of rice and italians survive on lots of pasta and Mexicans on corn and Irish on potatoes and English on bread (though bread didn't used to be quite as refined back then).... ? Or is the article saying all that only happened in the last 12,000 years (when agriculture took its greatest effect) and that isn't long enough?

I can understand that I don't survive well on carbs, my family history didn't each much carbs, but the whole human population?!

I'm totally confuzzled :P

e

My take on this one is: They dont eat that much of it - obtaining, making and eating a bowl of natural rice a day isnt the same as being able to go to the kitchen/drive thru/supermarket/restaurant... for cakes, bread, biscuits, readymeals in any quantity you fancy (in my case it used to be too much and too often!!). Also the lifestyle that goes with that kind of basic diet tends to be much more physical, so they probably manage to burn it off better???????????? Maybe??

[KarenJ]

I think about this a lot. If humans continue to eat this way, it may take another 25-50K years for humans to 'evolve' into a carb-eating (or herbivorous) species- fully able to thrive on the corn. If that's even possible. Without the foods we evolved on, won't our brains shrink? If it is true that our brains became so large and superior because of all the things we ate (we scavenged brains and other organs left behind by an original predator, before we learned to hunt), then it stands to reason that our brains would "devolve" us into a dumber species, and the Apes will take over the world. ;)

However, if one looks to the ever-increasing incidence of Type II diabetes among children (with all the inherent implications)- how do we know they will live long enough to reproduce, or be fertile enough to reproduce?

[ojoj]

Evolving doesnt mean that individuals change though, it means that those whose genes can take it will and those that cant wont. So eventually the strongest will survive and the rest will just die out. BUT, with modern medicines and human intervention, we already keep certain genes going that, left to nature would have dissapeared - so where does that take us in the future????????????????????

[eryalen]

Evolving doesnt mean that individuals change though, it means that those whose genes can take it will and those that cant wont. So eventually the strongest will survive and the rest will just die out. BUT, with modern medicines and human intervention, we already keep certain genes going that, left to nature would have dissapeared - so where does that take us in the future????????????????????
That is a scary thought.

[rightnow]

Why do Chinese survive on tons of rice and italians survive on lots of pasta and Mexicans on corn and Irish on potatoes and English on bread (though bread didn't used to be quite as refined back then).... ? Or is the article saying all that only happened in the last 12,000 years (when agriculture took its greatest effect) and that isn't long enough?
Well, they didn't all survive. ;-)

But the best answer to your question is looking at modern studies that specifically evaluate this kind of thing. For example, a massive study in China that because of its low-tech and regional foods was a great comparative study, found that the regions that ate just rice as the primary carb were healthy but those that added wheat as well definitely weren't. It is possible that some foods on their own are less damaging than when combined with something else.

People I've know who lived in italy have told me that meat/veggies were the primary foods there, but that spaghetti pasta (plain - with oil/herb, not sauce/cheese) was a constant 'side dish'. In fact I found it interesting as one guy described it as the first thing he would often eat, then he'd eat everything else. It reminded me of how when infants are nursing, the foremilk is high-carb, energy food basically to fill the demand of hunger, but then the rest of the milk is where the vitamins, fats, proteins are heaviest. The original italian pizza was a thin crispy cracker with oil and fish, I once read; the super heavy bread crust with lots of tomato sauce and cheese that we call pizza is an American thing. This reminds me of mexican food. If you go to the areas where the immigrants eat and hang out there, most of it is things like, part of a roasted chicken and black or pinto beans cooked with peppers and a couple small tortillas. But if you go to an American version of 'mexican food' you get massive quantities of tortillas and cheese and sauces and so on. Often food issues are 'combination' issues (e.g., eating fat won't hurt you, but eating a lot of fat with a lot of carb will). So I think it's hard to compare what we consider to be the food of other nations to health; it takes science to pull it apart into real specific quantities of stuff and measured results. It's entirely possible that the quantity of pasta vs. meats/veg was lower in the past when there were fewer people (one issue that has hugely affected meat intake is the growing population--grains can be grown to feed vastly more people than a meat-based society can), plus adding more refined carbs (more breads, let alone tons of fast food, boxed food, etc.) could make a huge difference.

I really think it's possible that overpopulation may end up being at the root of a lot of problems. I didn't know all the info about how the American diet shifted radically because the population increased radically until recently, so tons less meat/fat was available, meaning people shifted to carbs. We have far more people in any country, let alone on planet earth, than can be supported on "real food". So we ply millions (billions if you count everyone) with grains to "fill in" the giant hole that a lack of 'real food' creates. "Nature" will control populations -- when their prey is insufficient, more die of starvation esp in winter, and conception levels are naturally lower, so things stay in balance. thanks to agriculture, we threw a wrench in nature's ability to keep our population in balance.

[Beth1708]

On evolution -- my evolution textbook says something like that evolution works by *selective death*. In this case, if people who are not able to metabolize carbs are more likely to die than those who can (e.g. they starve), the genes to metabolize carbs will become relatively more abundant in the population.

As for the peoples that live mainly on carbs and don't get sick from it (e.g. the Chinese until recently) -- their total caloric intake was/is low and they don't eat refined carbs. Eating a large quanity of refined carbs is not healthy for them either, so I read.

Beth

[Angeline]

Well that doesn't go far enough. Evolution deals with reproduction, not death. If you die after producing and raising some offspring, then there little impact. If you die before reproducing then yes.

Anyway, doesn't high-carb have an impact on fertility rates? I was under the impression that some women who suffer from metabolic syndrome have a harder time to conceive. Now that could have an impact on evolution given enough time.

[mike_d]

Evolution may indeed be faster now, but it seems to going in the wrong direction "we are de-evolving" as Ophra once said.

[francisstp]

Ok, how can evolution be going at a faster rate if young people don't die and don't reproduce at high rates?

I would think this is the kind of situation which precludes a fast evolution, not encourage it. No?

[Nancy LC]

Well that doesn't go far enough. Evolution deals with reproduction, not death. If you die after producing and raising some offspring, then there little impact. If you die before reproducing then yes.
Not entirely. If you have more off-spring then your genes spread more. If you have a population of birds that only lay one egg, but then one bird starts to lay 2 eggs, then eventually that bird's genes may end up dominating.

[jono]

Nice article, I had a feeling evolution was working much faster than commonly thought.

Next stage is we'll control our own evolution and turn into immortal biomachines with super-intelligence and maybe new abilities like flying, and breathing under water. Or maybe evil transhuman robots will destroy us all first. Either way, it'll be fun to watch.

[KvonM]

Ok, how can evolution be going at a faster rate if young people don't die and don't reproduce at high rates?

I would think this is the kind of situation which precludes a fast evolution, not encourage it. No?
evolution can only work at the speed of the generational reproductive timespan. for humans, that used to be 18-20 years. nowadays it's more like 30 years.

when people say evolution is going faster, it means larger steps are being taken with each successive generation. you can think of it this way... say you walk at a pace of taking 1 step every 2 seconds. you could take very small steps within that 2 second time frame and travel from point A to point B slowly, or you could take as long a stride as you could within that same 2 seconds and move the same distance in less time. your legs aren't going faster, you're just covering more ground and getting to your destination faster than if you'd taken smaller steps.

[Legeon]

your legs aren't going faster, you're just covering more ground and getting to your destination faster than if you'd taken smaller stepsEvolution doesn't have a particular destination though, it could go anywhere.

[pengu1]

<terror>

If you are worried about where the population is probably going, watch "Idiocrasy".

</terror>

[francisstp]

evolution can only work at the speed of the generational reproductive timespan. for humans, that used to be 18-20 years. nowadays it's more like 30 years.

when people say evolution is going faster, it means larger steps are being taken with each successive generation. you can think of it this way... say you walk at a pace of taking 1 step every 2 seconds. you could take very small steps within that 2 second time frame and travel from point A to point B slowly, or you could take as long a stride as you could within that same 2 seconds and move the same distance in less time. your legs aren't going faster, you're just covering more ground and getting to your destination faster than if you'd taken smaller steps.


Ok, but I still don't see what process is making us evolve at all.

Take the case of the plague. A specific set of genes - the inability to fight the plague - precluded a massive number of people from reproducing : they were dead before they could. Combine this with a fertility rate often above 10 children per woman, and you have a very quick spreading of the genes of "successful" humans who don't die from the plague.

Now the situation seems to be the total opposite. Everybody gets to live past 30, there is not much discrimination as to who procreates, and fertility rates are below 2 children per woman.

So how can there be a fast evolutionary process in this situation?

[Nancy LC]

Ok, but I still don't see what process is making us evolve at all.

The only 2 things I can think of are random mutations and simply the number of children people have. In Western countries anyway. In undeveloped countries there's a lot of other factors.

[mike_d]

Mutation is slower now, the rays from close cosmic events like Supernova 1987A are much less than when man was evolving.

http://www.pbs.org/deepspace/timeline/index.html... the cosmic rays which
lead to mutation and evolution in living cells. These supernovae, then, are
key to the evolution of the Universe and to life itself.

[Nancy LC]

You can cause mutations with radiation. That's how we get new breeds of flowers. Bomb their seeds with xrays. Of course, it has to be a germ cell that mutates. There are mutagens in chemicals too (some in plants even). And there are mutations from mistakes in DNA replication, I think those would have to happen after fertilization though.

[KvonM]

Ok, but I still don't see what process is making us evolve at all.
evolution happens with sexual reproduction. our children are not exact duplicates of one parent. with each successive generation, genes combine in different ways than the original parent... one parent has blue eyes and brown hair, the other has brown eyes and blonde hair. the children can have blue eyes and blonde hair or brown eyes and brown hair. even if the steps are miniscule in distance, they are still there.

now granted, we don't have environmental pressures upon us forcing us to adapt or die, especially since humans tend to change the environment to suit themselves. but in the case of the original post and the article, the environmental pressure is self-inflicted. we don't HAVE to eat huge amounts of carbohydrate, we have chosen to. just as those of us on the board have chosen to eschew carbohydrates in favor of the foods that our bodies originally evolved to process.

many believe that the next "step" in human evolution will not be physical, it will be mental. there is an increase in psi or ESP capability, and it's a genetic trait that is often passed to successive generations.


So how can there be a fast evolutionary process in this situation?
keep in mind that "fast" is a relative term. if humans were able to sexually reproduce at 2 years of age, we'd see much "faster" evolution than we do now.

[KvonM]

And there are mutations from mistakes in DNA replication, I think those would have to happen after fertilization though.
they happen during fertilization, as the genes are combining. that's where you end up with various birth defects. i remember learning once that out of the millions of possible bad combinations that can happen during conception, there are about a dozen that have devastating effects and yet the fetus will still live.

(and here, i'm talking about actual screw-ups in how the genes combine that produce things like spina bifida and down's syndrome. i don't mean certain genetic markers that are expressed because one or both parents carry them.)

[eryalen]

Mutation is slower now, the rays from close cosmic events like Supernova 1987A are much less than when man was evolving.

http://www.pbs.org/deepspace/timeline/index.html
But radiation from CRT's (TV and computers) is hitting us much harder than anything from outside the atmosphere.