ChiefsPlanet - Science Are human beings diverging in size?

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Are human beings diverging in size? (https://chiefsplanet.com/BB/showthread.php?t=283429)

Small in size and tall in stature.

Their offspring may break the space time continuum

http://i.dailymail.co.uk/i/pix/2012/...13_468x762.jpg

This would not affect gene or allele frequencies. So I don't think there would be any noticeable differences short or long term.

Quote:

Originally Posted by B_Ambuehl (Post 10604472)

the average male has a ~30% lower testosterone level than a generation ago.

Got a link for this, playa?

Quote:

Originally Posted by Rain Man (Post 10604227)

I was thinking about this the other day. I think I've mentioned it before, but I'm alone and bored.

We have a social construct where women don't typically date guys who are shorter than them, and men don't typically date women who are taller than them. While a tall man may date women of any size, he's more likely to end up with taller women because there's less competition. A short man is typically going to be fishing almost exclusively off the petite end of the spectrum.

I'm not saying that it'll happen overnight, and there are a lot of confounding factors, but in the ultra-long term, you have a disproportionate number of pairings of tall genes and a disproportionate number of pairings of short genes. So that would logically mean that we're going to flatten the bell curve of heights over time with more tall people and more short people than we would get with random pairings. Right?

Then I wonder about maximum and minimum heights. Do humans have natural limits? With this socially selective breeding, can we keep hitting new maximum and minimum heights? In the dog world, mastiffs and Newfoundlands are probably six times bigger than generic domesticated dogs, and chihuahuas are 20 percent of the size of generic domesticated dogs. Can humans push the same limits and hit mature weights of 40 to 900 pounds? Can we go further? In a thousand millennia, if you're 14 inches tall, you're probably still looking for that 12 or 13 inch wife. And the process would accelerate because she's unlikely to date and marry the 9-foot, 900 pound subspecies of human. What's the upper and lower limit over the course of 100,000 years?

And did cro-magnons and ancient Egyptians have the same social preference? How much of a head start do we have? I'm thinking it's a new phenomenon because a lot of marriages in past times were arranged.

the main point I got from the post is that you are bored and you took the time to share that with us:D

Quote:

Originally Posted by ThaVirus (Post 10604686)

Got a link for this, playa?

I can't find the specific one I read a while back, but here are some similar findings:

http://heartiste.wordpress.com/2013/...terone-levels/

http://www.ncbi.nlm.nih.gov/pubmed/17062768

My Wife is tall. She's constantly bitching about wanting to be short.

I am sure there is a study linking height over time.

Lincoln, in his time was a giant at 6'4". Then he added to it with the Stove Pipe hat. I believe Washington was 6'1". The median was ~5'4"?

I toured castles in Europe and many door/archways were much shorter then you find today. I saw a suit of armor that "Sir Whatchamucallit the Giant" wore and it was for a 6'1" person. What was crazy thou was the size of the swords they wielded. Two handed swords were 6' long. How the heck did these munchkins swing those all day? They must have forearms like Popeye!

My dad's parents were both under 5'7. My dad is 6'4. I am 5'9. My brother is 6'1.

I think it's all about genetics...basically a crapshoot. Every tall family has a short relative, every short family has a tall relative.

Quote:

Originally Posted by Strongside (Post 10605563)

My Dad was 5'7 and Mom was 5'3. I'm 6'5 and all my Brothers are over 6'1. It's weird.

There's no correlation. My parents were average height and I'm 6'4". My five siblings are of average height. My HS BB teammates in the front court were taller than me. Their parents were of average height sans one mom. It's hit and miss and not something to lose sleep over.

There's always going to be exceptions. I'm talking about the bigger pattern underneath. I'm no Gregor Mendel, but it seems to me like if tall people continue to marry tall people over the course of a thousand years, their kids are on average going to be tall. And the opposite is true with short people. They're going to pull the distribution out on average.

The height of each sex within a breeding population will always follow a normal distribution. The stronger the height correlation among mating pairs, the more the distribution will broaden. The more people interbreed with people of various heights, the narrower the distribution will become.

Factors that will contribute to maintaining a normal (bell shaped distribution):

When people mate, the mean height of their offspring will be an average of the height characteristics of the two parents. An extremely tall parent will most often be mixing genes with a shorter parent (even if they are taller than average), thus pulling the tall parent toward the middle. For example a parent in the one percentile mixing with someone from the five percentile gives an offspring at the three percentile, on average.

Correlation of height characteristics between mating pairs is <1.

The height of the offspring will be a mixture of the height of the two parents, plus random variation. The random variation tends to smear the effects derived from correlation of mating pairs.

The middle is populated from both sides: offspring from tall people and short people will tend toward the mean, both due to breeding with people closer to the mean and random variation. Extremes can only be populated from one direction. In the above example of a three percentile offspring on average the random variation could propel them to a 0.5%, i.e. taller than either parent.

The breeding population is always greater in the middle than it is at the extremes.

All of the above assumes that the specific genes that contribute to the height characteristics of one parent are the same genes that contribute to the height of the other parent. If different genes are contributing to the height characteristics of the two parents, the offspring could experience synergism where the mean offspring is taller than either of the parents.

Your stating this with the supposition that all shorts breed with shorts. I don't think that's true, similar to how inter-racial marriage exists, so does inter....height marriage? You get the point. Plus there are also so many other biological factors that go into this as well.