human height increase

[lemur]

My general perception is that children usually mature to be a couple inches taller than their parents. If this would be a constant rate, human height would increase 1-2 feet every 12 generations. Presumably, this rate has increased - otherwise ancient humans would have been the size of rodents. Likewise, it is hard to imagine that average human height will be 10+ feet tall over the next decade or so. So what are are parameters of generational height increase and are we just in a period of history where rapid height increase is due to advances in nutrition and exercise/physical activities that influence growth?

[Mr Skeptic]

Nutrition... it may not be as wholesome as in the "good old days", but at least there's enough of it. Probably has nothing to do with the Bovine Growth Hormone we get in our milk nowadays.

[ewmon]

I had read this previously although I don't know how valid it is.

Carleton S. Coon ... set forth a relationship between stature and calcium [content] in agricultural lands.

from National Anthropological Archives

 

The basic idea is:

 

Stature ◄— Bones ◄— Nutrition ◄— Calcium ◄— Soil

 

 

 

Pages 1 through 7 (and perhaps others) are interesting here: The Chemistry of prehistoric human bone

Edited September 23, 2010 by ewmon

[pippo]

Nutrition... it may not be as wholesome as in the "good old days", but at least there's enough of it. Probably has nothing to do with the Bovine Growth Hormone we get in our milk nowadays.

 

I dunno, skeptic, then why not very long ago the tallest people were in Sudan, which = starvation/war/disease/poor nutrition as a whole, as in eat mostly rice in bags.

 

Recently, the tallest are in Denmark/Norway. Kinda like the Viking spirit, eh? Incidentally, those are the richest countries in the world (or in the top 5 or so). Anyway, I find the sudanese thing quite shocking. To me its genetics, #1.

 

You see it also in animal husbandry, especially the smaller the animal, the most research proven. For example, mink farms-typically hold 20-80,000 mink. generations /genetics change quickly, unlike bovines. The biggest factor in raising huge mink is genetics, not nutrition. Are men like mink?

[Ophiolite]

human height increase what are the causes and limits

Anything much over five miles and you'd have to bend down to breath.

[HGHEaston]

For increase your height you can use Human Growth Hormone... It is a well-known fact that HGH is responsible for a person growing taller, but there are other areas where HGH helps in human development. HGH is proven to reverse muscle wasting in persons suffering from AIDS. It is claimed (not yet proven) that HGH supplements slow down the ageing process making one live longer.

Edited March 15, 2011 by Mr Skeptic
de-linked

[thinker_jeff]

Please delete this post.

 

 

Edited March 15, 2011 by thinker_jeff

[thinker_jeff]

Delete this, too.

 

 

Edited March 15, 2011 by thinker_jeff

[thinker_jeff]

My general perception is that children usually mature to be a couple inches taller than their parents. If this would be a constant rate, human height would increase 1-2 feet every 12 generations. Presumably, this rate has increased - otherwise ancient humans would have been the size of rodents. Likewise, it is hard to imagine that average human height will be 10+ feet tall over the next decade or so. So what are are parameters of generational height increase and are we just in a period of history where rapid height increase is due to advances in nutrition and exercise/physical activities that influence growth?

 

This general perception may not be true. Some research indicates that Australians are getting shorter.

 

Link: http://www.earthtime...rcher-says.html

Edited March 15, 2011 by thinker_jeff

[Marat]

Harvard University began a study of typical undergraduate dimensions in the 1890s and commissioned statues to be built showing the average undergraduate in each generation. This study showed that Harvard students, who supposedly had better health and nutrition than most people, reached their maximum height before the rest of the U.S. population. Now the population increases noted from the 1890s on are now longer occurring, since the optimal human height has been reached. These statues are still available for inspection at the Harvard Museuam (aka the Peabody Museum) today.

[elihu]

Excuse me, but how could we define a "man"?

[The Peon]

Bear in mind that the taller one is, the more massive one tends to be, which means the more energy consumption one has. I tend to think most animals are not larger because environment does not allow it, more so than genetics. In the age of Dinosaurs a few species grew substantially over rather rapid period of time. This was due to an abundant and lush source of vegetation, which in turn allowed prey animals to gain size which in turn finally allowed predators to gain size. The extinction event which happened 65 MYA was primarily due to the collapse of the lush vegetation.

[Marat]

What sets the theoretical limit to the size of any animal, even we assume that nutritional requirements were satisfied? Is it the tension between the electrostatic forces holding it together and the gravitational forces pulling it apart? Surely there couldn't be a creature crawling about which was the size of New Jersey!

[CharonY]

There are certainly also biological limits rather than purely physical ones. Gigantism is caused by a genetic mutation, for instance. Also for a longer perspective:

My link

 

Based on a modest sample of skeletons from northern Europe, average heights fell

from 173.4 centimeters in the early Middle Ages to a low of roughly 167 centimeters

during the seventeenth and eighteenth centuries. Taking the data at face value, this

decline of approximately 6.4 centimeters substantially exceeds any prolonged downturns

found during industrialization in several countries that have been studied. Significantly,

recovery to levels achieved in the early Middle Ages was not attained until

the early twentieth century. It is plausible to link the decline in average height to climate

deterioration; growing inequality; urbanization and the expansion of trade and

commerce, which facilitated the spread of diseases; fluctuations in population size that

impinged on nutritional status; the global spread of diseases associated with European

expansion and colonization; and conflicts or wars over state building or religion.

Because it is reasonable to believe that greater exposure to pathogens accompanied

urbanization and industrialization, and there is evidence of climate moderation,

increasing efficiency in agriculture, and greater interregional and international trade

in foodstuffs, it is plausible to link the reversal of the long-term height decline with

dietary improvements.

[Marat]

I suppose one limit on the potential size of biological entities would be the height of the atmosphere and the diminishing concentration of oxygen at higher levels. This would force New Jersey-sized creatures to crawl fairly low to the ground, which would increase friction and so also increase the demand for oxygen to metabolize the calories needed to deal with the friction. This is perhaps part of the reason why whales, the largest animals, live in the oceans and so reduce friction.

 

Another issue I can imagine if we factor nutrition into the calculation is that the ratio between the size of the creature and the mass of items in the environment needed for nutrition could not exceed a certain limit, since the calories required to keep moving to find more sources of calories would eventually exceed the the nutritional calories that could be gathered by moving.

[Katherine Reeds]

Now days we do not have proper nutrition in food which is required for the building up of body blocks.

[biologywatcher]

Marat--

As far as limitations to growth go, there are physiological ones as well. If we were tall enough, what sort of a circulatory system would we need to supply blood to the brain? Giraffes are a good example... their hearts are about 11 kg. Maybe there would be thermoregulatory considerations too, just because larger organisms retain more heat--in extreme environments, anyway. There would also have to be some serious bone remodeling if we were going to get that tall. Organism mass scales to the cube of a linear dimension, and cross sectional area of bones for instance, which are responsible for supporting the mass, only scales to the square of the linear dimension... So if humans were to get really tall, we wouldn't have the same general shape that we do now. I feel like D'Arcy Wentworth Thompson's On Growth and Form touches on some of this stuff.

 

With whales--the ocean allows them to get that big because of buoyancy. If something the size of a blue whale were to exist as a terrestrial animal, it wouldn't be able to support its own weight. I think.

 

I really have no idea about the more proximate (within one generation, say) limits on height.

[Marat]

With respect to the circulatory demands of having a brain so far above the heart in giraffes, I have always wondered how they deal with the massive blood pressure required to preserve usable consciousness when the head is up so high. Somehow, even though they are mammals like us, a blood pressure of 220 over 100 doesn't seem to cause the same sort of damage to them that it would quickly cause in our kidneys and retinas, for example.

[rktpro]

But no one is too short to let his feet reach the ground.

[John Cuthber]

As I understand it, people who are conspicuously tall already suffer from increased risks from back problems etc. So there's already some pressure on people not to get taller.

After millions of years, perhaps we have already reached the "right" height for our evolutionary niche.

[r_g]

As I understand it, people who are conspicuously tall already suffer from increased risks from back problems etc. So there's already some pressure on people not to get taller.

 

That's mostly a muscular issue though, not a definite physical limitation. The nutrition hypothesis sounds too simple for me. There are also giant people in regions of the earth where the nutrition standards didn't really significantly improve in the last few hundred years. It's probably some genetic development/evolution, although I can't really find a reason why.

 

But it sure is a very interesting topic, indeed.

[Realitycheck]

I dunno, skeptic, then why not very long ago the tallest people were in Sudan, which = starvation/war/disease/poor nutrition as a whole, as in eat mostly rice in bags.

 

Recently, the tallest are in Denmark/Norway. Kinda like the Viking spirit, eh? Incidentally, those are the richest countries in the world (or in the top 5 or so). Anyway, I find the sudanese thing quite shocking. To me its genetics, #1.

 

The people in Denmark are among the tallest, they are among the wealthiest, they are among the most genetically advanced - dating back to the blond-blue-eyed mutation 5-10,000 years ago.

 

I've read that the future of man is destined to be divided into roughly two classes- a tall, athletic type and a short, gnomish type, but that seems really ignorant and classist. Would you consider that to be natural selection in light of the golden rule? I think that the introduction of money negates that aspect of natural selection to some extent. I wonder what other types of mutations could occur to generate forms of superiority other than just sexual attractiveness. I guess the possibilities are endless.