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D'kian
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Last month's Discover magazine had an interesting article regarding ongoing human evolution. Among other things the authors bash the idea that humans stopped evolving with the advent of technology. Usually I'd just skip the bashing and go on with the article, but this one tackled one of my assumptions. So:

My assumption wasn't that humans had stopped evolving. That's simply not possible as long as humans keep on breeding. My assumption was that evolution was no longer relevant because with technology we can alter our environemnt to suit ourselves. This is true, and humans do keep on living in environemnts they're not adapted to (spend a winter in Canada, now imagine that without any technology at all, not even a sharpened stick). But that doesn't mean some changes to our genetic code have not been relevant. And yet technology keeps overcoming evolution.

For example, a mutation that has become very widespread allows most of us to digest lactose, a sugar found only in milk (any knid of milk). Some people lack this mutation and can't digest lactose, we call them lactose intolerance. These people are unable to benefit from milk and dairy products. Such people, until recently, would have had a harder time obtaining protein. Milk and dairy are inexpensive compared with other protein sources (such as meat). But in a prosperous area that doesn't matter much, and milk and dairy are more a matter of taste than survival. I've known plenty of people with lactose intolerance, and they were as healthy as everyone else.

And now lactose is not even a factor. There's lactose-free milk now, and increasingly lactose-free dairy products. There are also pills that aid in digesting lactose.

BTW the lactose mutation isn't unique to humans. All mammals are born with the ability to digest lactose, since all mammals produce it int heir milk (humans more than most). But as almost all animals loose access to milk once they're weaned off it, they also loose the ability to digest it (it's like discarding a paper towel once you used it). With technology that led to farming, that led to keeping livestock, that led to a diary industry, that changes. But other animals shared in our success. Many dogs, for example, retain the ability to digest lactose (every dog I ever owned positively loved milk, cheese and ice cream). Many house cats do as well. Even rats can feed on dairy products (though of course a rat's diet is nothign if not eclectic).

And this points to another interesting notion: when we evolve a certain useful trait, do our domestic animals and parasites evolve a similar trait to keep up?

A point in the Discover article is that as a population grows larger, the chances of useful mutations increases. This is very true in regards to humanity, but also in regards to animals associated with us: pets, livestock and parasites. It would be interesting to see how fast do dogs evolve as compared to humans.

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In my view technology is evolution. I view evolution as being advancments in information technology. Its latest most important advacment was reason. Since reason is a natural process, then I don't see why the products of reason are not natural as well. I think technology is just the next step of evolution.

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In my view technology is evolution. I view evolution as being advancements in information technology. Its latest most important advancement was reason. Since reason is a natural process, then I don't see why the products of reason are not natural as well. I think technology is just the next step of evolution.

Well, evolution is a word which existed before Darwin's Theory of Evolution, and continues to exist and mean something different (much broader) than that scientific theory. So yes, in that sense the evolution of technology is indeed an "evolution", just like the evolution of Literature, Philosophy, or TV wrestling and the Maury Povich Show.

That doesn't mean they have anything in common with the Theory of Evolution. It most definitely doesn't refer to the advancement of technology (or even the breeding of different dog species by humans, I think).

Sure, technology often advances in somewhat similar fashion to the evolution of species, as described by Darwin and later others. Somewhat similar, but not similar enough to just brand them "one and the same". Often time, a technological leap is the product of a single brilliant mind, competition has nothing to do with it.

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While artificial selection is certainly a powerful force, natural selection still plays a very important role in shaping the genetic makeup of future generations. For example, consider people with HIV. In Europe, a mutation in the CCR5 gene gives some individuals resistance to HIV. Individuals who do not have the mutated allele will become infected with HIV, and if infected before they reproduce, their disease will mentally and physically reduce their ability (and desire) to survive and reproduce. Some individuals will still reproduce, but this number will be low compared to the extent they would reproduce if they were not infected. Individuals with the mutated CCR5 gene will be exposed to HIV, not become infected, and their comparitve ability to survive and reproduce will be much higher. This mutation will naturally be selected to pass on to future generations.

How can artifical selection affect this process? HIV medication can alleviate some of the symptoms that people endure, but eventually, AIDS will lead to their death. So while it might increase the reproductive and survival capacity a little, it will never be able to compete with natural selection for individuals reproducing who have the CCR5 mutation.

Another example is the sickle cell allele in Africa. Individuals who are homozygous recessive experience a terrible quality of life. Heterozygotes, however, enjoy an advantage since their genotype gives them resistance to malaria, which is rampant throughout the continent. Most Africans who are homozygous recessive and consequently suffer from sickle cell anemia do not get treatment like it is available in industrialized nations. The frequency of the recessive allele naturally decreases, while the frequency of the dominant allele increases.

So while artificial selection is an important factor to consider when determining whether a population has evolved, natural selection still plays an important part in determining the genetic makeup of future generations.

Edited by Mimpy
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In the 9th grade, my Biology book mentions that there are four kinds of evolution: Physical(changes in structure of heavenly bodies), Chemical(changes in chemical compounds found on heavenly bodies), Biological(genetic mutations; survival of the fittest) and Cultural(technology and art). All of them are happening, so yes, humans are evolving, both in biological and cultural way.

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How can artifical selection affect this process? HIV medication can alleviate some of the symptoms that people endure, but eventually, AIDS will lead to their death. So while it might increase the reproductive and survival capacity a little, it will never be able to compete with natural selection for individuals reproducing who have the CCR5 mutation.

well, AIDS is much more complicated than that. Whereas people diagnosed with it used to die shortly thereafter, now they can hang on for years, with a low viral load and a low probability of infecting anyone else. Then there's the period of incubation during which infection is possible. Not to mention the fact that infection can take place at any age, which further complicates matters.

Most Africans who are homozygous recessive and consequently suffer from sickle cell anemia do not get treatment like it is available in industrialized nations. The frequency of the recessive allele naturally decreases, while the frequency of the dominant allele increases.

Yes. But for people fo African descent in other countries, notably the US and Europe, the sickle cell gene does not confer any advantage (low probability of catching malaria), and those affected with anemia do get treatment and live long, full lives. It's similar to the Tay Sachs disease gene which may also ahve offered protection against TB, except thos with Tay Sachs die very young.

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The point is that while artificial selection can eliminate advantage of certain variations and give everyone equal differential success for those variations, it certainly cannot (yet) for other variations.

Also, selection is not the only factor that causes a population to evolve. Genetic drift, mutation, and migration will always fluctuate allele frequencies.

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The point is that while artificial selection can eliminate advantage of certain variations and give everyone equal differential success for those variations, it certainly cannot (yet) for other variations.

Yes. I've been thinking more about it, and I've decided the real question is: how much does natural selection still affect human evolution?

The answer to that is tricky. Evolution has to be studied in retrospect, mostly, and not so much as it is developing. That is, most changes are noted some time after they take place, and changes take time to happen and more time to spread throughout a population.

Culture and technology matter a great deal, too. These days most people get married and have children. Those who can't ahve children are a small minority. In many countries they are even a smaller minority because there's access to fertility treatments. How many people do you know who had children by the use of drugs or procedures like in-vitro fertilization? (BTW In-vitro sometimes uses donor sperm or eggs, but not always. In fact the donor genetic material is an interestin issue all by itself).

Also, selection is not the only factor that causes a population to evolve. Genetic drift, mutation, and migration will always fluctuate allele frequencies.

Indeed. there's something called the Founder Effect. some genetic defects are common among certain populations, yet they don't confer any particualr advantage. This happens, for example, when a new colony is established and one of the founders (hence the name) has a recessive gene for a certain condiction, and that founder proceeds to have many children. Then the gene spreads more widely in that population than it's the norm elsewhere. That's believed to account for much of the persistence of cystic fibrosis.

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  • 3 weeks later...
Yes. I've been thinking more about it, and I've decided the real question is: how much does natural selection still affect human evolution?

The answer to that is tricky. Evolution has to be studied in retrospect, mostly, and not so much as it is developing. That is, most changes are noted some time after they take place, and changes take time to happen and more time to spread throughout a population.

Culture and technology matter a great deal, too. These days most people get married and have children. Those who can't ahve children are a small minority. In many countries they are even a smaller minority because there's access to fertility treatments. How many people do you know who had children by the use of drugs or procedures like in-vitro fertilization? (BTW In-vitro sometimes uses donor sperm or eggs, but not always. In fact the donor genetic material is an interestin issue all by itself).

Indeed. there's something called the Founder Effect. some genetic defects are common among certain populations, yet they don't confer any particualr advantage. This happens, for example, when a new colony is established and one of the founders (hence the name) has a recessive gene for a certain condiction, and that founder proceeds to have many children. Then the gene spreads more widely in that population than it's the norm elsewhere. That's believed to account for much of the persistence of cystic fibrosis.

Jus an FYI, founder effect doesnt have to be negative. Population of French Canadians have a variant in their HDL gene that is protective against heart disease. In a simliar manner, the French Paradox (some attribute to red wine consumption), is the characteristic of low LDL levels in populations of individuals who eat high fat content diet.

I also think that North American average age that women have their first child will result in a darwinian move toward selection or preservation of fewer chromosomally abnormal ova in late maternal age.

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Jus an FYI, founder effect doesnt have to be negative. Population of French Canadians have a variant in their HDL gene that is protective against heart disease. In a simliar manner, the French Paradox (some attribute to red wine consumption), is the characteristic of low LDL levels in populations of individuals who eat high fat content diet.

To assess whether a Founder effect is positive or not, you must determine if the alleged advantage occured because of the Founder effect. I don't know the particulars of the example you have mentioned, but it is not clear from what you said that the advantage occurred because a group of people isolated itself from the rest of the population. A small population always increases the risk of inbreeding, which is never to the offspring's advantage. Consider the Amish in Eastern Pennsylvana, who are plagued with a myriad of diseases.

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  • 4 months later...

I discovered somethign interesting yesterday, lactose-free baby formula.

Baby formula is a substitute for breast-milk, therefore it is rich in lactose. I'm surprised there are people born lactose intolerant. I realize I shoulnd't be, as there are people born with every kind of genetic defect there can be. But lactose intolerance usually sets in later, after the weaning age. After all, mammals can depend only on feeding with breast-milk for the first few months of life.

Now, this wasn't some highly specialized product available in pharmacies. I found lots of it neatly stacked to other kinds of baby forumal in the local supermarket. So either this condition is a great deal more widespread than I could think of (I dind't actually think of it), or it's merely aprt of a larger lactose-free fad. I've noticed people who can handle lactose perfectly well buy lactose-free milk. Some brands market it as "easier to digest," as though digestion were ahrd wok. Some people on a diet even buy fat-free, lactose-free milk because it ahs even less calories.

Any thoughts?

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I discovered somethign interesting yesterday, lactose-free baby formula.

I think lactose-free milk for babies is used only temporarily. You can be "lactose tolerant" (genetically) but still be lactose intolerant because of some temporary illness (e.g. diarrhea) which hampers your production of lactase (the enzyme that splits lactose).

As a side note: Drinking cow milk is certainly not the healthiest thing to do, even if it's organic. Many cows produce beta-casein A1 which can cause an addiction and can have effects on the brain, while beta-casein A2 does not. Goat milk seems to be a better choice.

Edited by Clawg
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I think lactose-free milk for babies is used only temporarily. You can be "lactose tolerant" (genetically) but still be lactose intolerant because of some temporary illness (e.g. diarrhea) which hampers your production of lactase (the enzyme that splits lactose).

As a side note: Drinking cow milk is certainly not the healthiest thing to do, even if it's organic. Many cows produce beta-casein A1 which can cause an addiction and can have effects on the brain, while beta-casein A2 does not. Goat milk seems to be a better choice.

Are there any actual studies causally linking A1 to any problems, or are we simply talking about population correlation studies?

Edited by brian0918
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Are there any actual studies causally linking A1 to any problems, or are we simply talking about population correlation studies?

Epidemiological evidence, you can read some articles googling for a1 cows casein.

Personally, I suffered some withdrawal symptoms when I went "cold turkey", although that wasn't a scientific experiment (I didn't switch from A1 to A2, I simply stopped drinking milk / eating cheese).

*might* be a reason why cheese is so popular :P

But not everyone is affected, it depends on the permeability of the intestine (caused by alcohol, infections, bad diet etc., it's a complex field of study).

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Epidemiological evidence, you can read some articles googling for a1 cows casein.

As I said, they are merely studies comparing populations, which don't tell you anything and often implicate effects as causes. Stephan at Whole Health Source has been blogging for a long time about the problems with epidemiological studies, and it is covered at length by Taubes in Good Calories Bad Calories. Here is what Stephan has to say about A1:

I read the original study correlating A1 milk with international heart attack deaths, and the correlation is indeed striking (at least in the countries considered). But when you consider observational studies that have been done within countries on an individual person level, dairy is most often protective against heart attacks, regardless of fat content. So this presents a paradox. There are two ways to resolve it. One is to say that the reason the individual level observational studies couldn't detect an effect is because everyone was eating dairy to some degree, and the required amount for toxicity is very low. The other way to resolve the paradox is to say that A1 milk is simply a marker of an industrial food system, because Holstein cows are A1 and they make the largest quantity of watery milk so they're used in most industrial food systems (except parts of France). The Masai drink A2 milk.

I favor the latter explanation, and in any case you can circumvent the potential problems with dairy protein by eating butter. My best guess is that dairy is generally healthy if tolerated, but many people do better without it.

Edited by brian0918
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I think lactose-free milk for babies is used only temporarily. You can be "lactose tolerant" (genetically) but still be lactose intolerant because of some temporary illness (e.g. diarrhea) which hampers your production of lactase (the enzyme that splits lactose).

Thank you. THat makes mroe sense than some widespread, random mutation.

As a side note: Drinking cow milk is certainly not the healthiest thing to do, even if it's organic.

Milk is high in fat and cholesterol, so of course it's not that healthy. When I drink milk (usually with chocolate or coffee), I get fat-free milk. Still, a little milk now and then is ok, as well as a little cheese and other dairy. I don't have dairy or milk every day. It's a good source of calcium, too. In the old days, the concentrated fat content would have been a boon to early agrarian societies heavily dependent on human labor.

Many cows produce beta-casein A1 which can cause an addiction and can have effects on the brain, while beta-casein A2 does not. Goat milk seems to be a better choice.

Goat milk is lower in fat, too. But compare a cow to a goat, or a sheep. Cows are huge and therefore produce a lot of everything (leather, milk, meat and bone). Pretty much every last bit of cow is used in some form or another. If cows could be genetically modified to grow wool, that would be the cheapest source of wool you ever saw (not that wool is expensive).

Anyway, economics tells you cow milk is more abundant and cheaper than goat or sheep milk.

I can't say I've ever felt any addictive effects. But then see what I said about how much dairy and milk I have. Still, as I said dogs may have evolved lactose tolerance to keep up with us, all the dogs I ever owned were positively happy when I gave them cheese or ice cream (I quit giving them milk after one year). It's hard to tell with dogs, because they are happy whenever they're fed, but I knew my dogs' quirks. I'd say cheese made them happier than anything but beef.

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Milk is high in fat and cholesterol, so of course it's not that healthy.

More misinformation. As an Oist, I have learned to distrust govt-induced recommendations. That has come to include dietary recommendations from the FDA/ADA/AHA/etc, and for good reason. Contrary to popular belief, high fat / high cholesterol is healthy. It is high carbohydrate that causes obesity, heart disease, and the metabolic syndrome.

Read these two posts on Diana Hsieh's blog:

http://www.dianahsieh.com/blog/2008/09/new-diet.shtml

http://www.dianahsieh.com/blog/2008/10/what-i-eat.shtml

And watch this lecture from UCSF endocrinologist Robert Lustig:

As for how the mainstream notion that fat and cholesterol makes you fat got started, check out Gary Taubes's lecture here:

http://video.google.com/videoplay?docid=4362041487661765149

and the movie Fat Head (clips here:

).

When I drink milk (usually with chocolate or coffee), I get fat-free milk.

I drink whole milk. I also eat the fattiest ground beef, fattiest cuts of steak, eggs and bacon every day, whole milk yogurt, high fat cottage cheese, all other meats, cheese, and some vegetables and minimal fruit. Eating this way, I lost 20lbs in a couple months (and an additional 10lb over the next couple months) and got off my blood pressure medication, all without any exercise. I also ate whenever I was hungry. No attempt was made to knowingly restrict my calories.

Before that I was trying to lose weight eating low fat everything, cutting calories, exercising like crazy. It didn't work because it physically couldn't. Your body will sooner see you die than give up your fat so long as you are eating a high carb diet, no matter how much you restrict your calories.

And everyone I've recommended this diet to (family and friends) has seen the same results, as have the people they've subsequently recommended it to.

Edited by brian0918
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I drink whole milk. I also eat the fattiest ground beef, fattiest cuts of steak, eggs and bacon every day, whole milk yogurt, high fat cottage cheese, all other meats, cheese, and some vegetables and minimal fruit. Eating this way, I lost 20lbs in a couple months (and an additional 10lb over the next couple months) and got off my blood pressure medication, all without any exercise. I also ate whenever I was hungry. No attempt was made to knowingly restrict my calories.

Certain types of cholesterol (the kind found in high fat beef, pork, cheese) get deposited on the walls of people's arteries, cause blockages and increase the risk of hearth attack.

People who recommend low carb high fat diets are confusing being thin with being healthy. The alternative isn't between being fat + unhealthy, and being thin+healthy+hungry.

The way to staying away from obesity related diseases is to not over-eat, exercise (be physically active) regularly, and don't eat things that will clog your arteries, or not provide you with enough vitamins and minerals, or don't contain enough fiber (like over-processed food, and juices instead of fruits), and to pay attention to whatever other medical condition you have, that could cause your doctor to recommend a diet. That's all, you don't need to be thin, you can be overweight and perfectly healthy, for instance. Overweight is not unhealthy, only obese is.

That makes sense, recommending a diet full of foods that do clog your arteries with cholesterol, that are processed and don't have enough fiber or vitamins, does not.

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Certain types of cholesterol (the kind found in high fat beef, pork, cheese) get deposited on the walls of people's arteries, cause blockages and increase the risk of hearth attack.

Wrong. First off, dietary cholesterol is of no concern - it is the result in your body that matters. Second, we're not even talking about cholesterol, but lipoproteins. HDL and LDL are not cholesterol. With that said, HDL is good - you will get this from a high fat diet. And HDL is inverse to triglycerides, which are the strongest connection to obesity. So that will go down, which is good. As for LDL, it is neither good nor bad - what matters is a component of it, the VLDL, its count, as well as its size. Large puffy VLDL are not a problem, they don't get stuck in cracks in the arteries - Small, dense VLDL do, they are the concern. And the foods that cause these are foods that spike blood sugar, which are highly-refined carbohydrates.

Had you bothered to watch any of the videos I linked you, or read any of the articles, you would know this.

People who recommend low carb high fat diets are confusing being thin with being healthy.

As I said, not only did I lose weight, I got off my blood pressure medication. My blood pressure normalized. I am no longer hypertensive. No confusion here. Just straw men on your end.

The alternative isn't between being fat + unhealthy, and being thin+healthy+hungry.

Who mentioned being hungry? Given that obesity has the strongest link to metabolic syndrome, that is the strongest reason to not be obese.

The way to staying away from obesity related diseases is to not over-eat, exercise (be physically active) regularly, and don't eat things that will clog your arteries

Begging the question. Also not specific or good advice. Your body will sooner see you die than let you lose fat so long as you are on a high carb diet, no matter how much you restrict your calories. Taubes references a study where they put top gun air force guys on a restricted calorie diet (1200 cal I think) and after a year or two, they had lost almost no weight and were constantly hungry, weak, and hallucinating.

That makes sense, recommending a diet full of foods that do clog your arteries with cholesterol

Check your premises. You're assuming that your "sense" is grounded in anything. Saying that cholesterol clogs your arteries already shows you have no clue how the body works. Watch the videos, read Diana Hsieh's blog, read Good Calories Bad Calories (or at least the description, so you know it's not just some stupid self-help or fad-diet book).

Edited by brian0918
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Certain types of cholesterol (the kind found in high fat beef, pork, cheese) get deposited on the walls of people's arteries, cause blockages and increase the risk of hearth attack.

Don't commit to 'conventional wisdom science' learned from popular accounts in newspapers and T.V. There is no direct path from the food to the artery blockages, so dietary recommendations based on that theory are bad advice.

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Don't commit to 'conventional wisdom science' learned from popular accounts in newspapers and T.V. There is no direct path from the food to the artery blockages, so dietary recommendations based on that theory are bad advice.

I am not an expert in human biology (I am the opposite of one), so I won't be able to argue any of this down to the science, but I have heard actual doctors talk about certain types of cholesterol being harmful, and of people with heart problems being told to cut down on fat meat by their doctors, I haven't just seen it on TV.

I also haven't read books on the subject, stupid or otherwise.

Begging the question. Also not specific or good advice. Your body will sooner see you die than let you lose fat so long as you are on a high carb diet, no matter how much you restrict your calories. Taubes references a study where they put top gun air force guys on a restricted calorie diet (1200 cal I think) and after a year or two, they had lost almost no weight and were constantly hungry, weak, and hallucinating.

That's no proof at all that a 2000 calorie, balanced diet, with both carbs and protein, wouldn't have worked to keep those men fit and not hallucinating.

Plus, you just built your own straw man, since I never said anything about a "high carb" diet.

Edited by Jake_Ellison
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I have heard actual doctors talk about certain types of cholesterol being harmful, and of people with heart problems being told to cut down on fat meat by their doctors, I haven't just seen it on TV.

You've heard a lot of experts give a lot of bad advice in their respective fields (financial comes to mind).

I also haven't read books on the subject, stupid or otherwise.

Plus, you just built your own straw man, since I never said anything about a "high carb" diet.

You've mentioned nothing specific. "Balanced diet" - what does that mean? If the carbs are anywhere near the daily recommended value, or even 1/3 to 1/2 that amount, it is still high carb.

That's no proof at all that a 2000 calorie, balanced diet, with both carbs and protein, wouldn't have worked to keep those men fit and not hallucinating.

Until you understand the problem, you won't realize why your recommendations are pointless. You cannot possibly take a 2000 calorie diet high in carbs (as the mainstream usually means by a "balanced diet") and say it will work for everyone. Obese people with high insulin resistance would be starving trying to eat only 2000 calories. They need to get their insulin sensitivity to normal, and the only way to do that is to not spike blood sugar, so avoiding highly refined carbohydrates. And the way to prevent obesity from reoccurring is to prevent the cause of insulin resistance, which again is spiking the blood sugar, which is caused by highly refined carbs.

Watch the http://www.youtube.com/watch?v=dBnniua6-oM, 90 minutes, and maybe I'll bother to continue replying. It's not worth my time to teach this to you.

Edited by brian0918
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