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chaloobi
SFN Regular
1620 Posts |
 Posted - 01/05/2005 : 12:07:19
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From a certain perspective, civilization can be said to be all about removing natural selectors from our lives. One basic right everyone seems to have all over the world in every society - excepting China, of course - is to breed as much as we want. So the only real natural selector is against those who don't want to breed. And since in China, everyone's supposedly equally restricted, then there's no local selectors there either. But of course rural folks don't follow the rules as much and they do kill their girl baby's in hopes of a boy . . . not sure of what if any evolutionary consequence there is of that . . . But I digress.
Anyway, so, humans arn't evolving much. And unless 1 or more of 3 things happens, they won't:
1. We implement some kind of natural selection ourselves - allowing some to breed while restricting others based on some criteria or other.
2. Genetic engineering the results of which can be passed on to future generations via sexual reproduction thereby entering the human genome.
3. Civilization collapses, allowing the reassertion of natural selectors - like predators, genocidal warfare, droughts, competition for food and/or women, and so on.
What else? Anyone disagree? Let's discuss.
EDIT: BTW - so what affect does this reduction in the fertility rates below population replacement level have on this issue of human evolution anyway? If you take the world population in total, can't you say that those who are voluntarily, for whatever reason, breeding less are losing the ulitmate evolutionary game as a result? Is it safe to say that if the trend continues, then modern, industrial, technical civilization is itself a characteristic that is selected AGAINST! Can you imagine such a thing! Poverty and relative barbarism is a survival characteristic of all things!
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-Chaloobi
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Edited by - chaloobi on 01/05/2005 12:42:29
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Ricky
SFN Die Hard
USA
4907 Posts |
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chaloobi
SFN Regular
1620 Posts |
 Posted - 01/05/2005 : 12:43:30 [Permalink]
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quote:
Originally posted by Ricky
Natural selection works using the method: if it survives, it works.
Now does it matter if we are surviving because of technology or biology? What is the difference? We are surviving either way.
Read my edit too. Thanks. |
-Chaloobi
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chaloobi
SFN Regular
1620 Posts |
Posted - 01/05/2005 : 12:44:31 [Permalink]
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quote:
Originally posted by Ricky
Natural selection works using the method: if it survives, it works.
Now does it matter if we are surviving because of technology or biology? What is the difference? We are surviving either way.
Well, it's not really about surviving, it's about the lack of selectors in the population. We're just breeding like rabbits but there's no wolves to eat the slow runners before they have children. So to speak. |
-Chaloobi
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| Edited by - chaloobi on 01/05/2005 12:45:04 |
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filthy
SFN Die Hard
USA
14408 Posts |
Posted - 01/05/2005 : 13:16:07 [Permalink]
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Um, pretty broad statment, 'loobi. I must disagree for the simple reason that biological evolution never entirely stops. It never sleeps. But perhaps appears to, for a brief while...
Ever since the last ice age, our enviornmental conditions have been all but ideal for our species (with minor variations here & there). Therefore, any mutation that might benefit us under other conditions simply never needed to be selected. It was to the species' advantage to stay pretty much as it was. If those conditions were to change, there can be little doubt that we would slowly change with them. Or not. 
As for recent evolution, we are taller, on the average. And this in just the last, couple of thousand years. An adult male at the time of Jesus might have been only 5'4'' to 5'6'' tall. This can also be seen in medevale suits of armor as well -- those guys were small! Few, modern men could fit into one.
Of course, while this increase in higth, largly selected for by our females who themselves became taller as a genetic result, is ok today, it could become a serious disadvantage in a changed environment.
Interesting thought....
Edit: I have no idea what the fall-off in fertility might result in, if indeed it is enough to affect the species as a whole.
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"What luck for rulers that men do not think." -- Adolf Hitler (1889 - 1945)
"If only we could impeach on the basis of criminal stupidity, 90% of the Rethuglicans and half of the Democrats would be thrown out of office." ~~ P.Z. Myres
"The default position of human nature is to punch the other guy in the face and take his stuff." ~~ Dude
Brother Boot Knife of Warm Humanitarianism,
and Crypto-Communist! 
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| Edited by - filthy on 01/05/2005 13:21:27 |
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Dave W.
Info Junkie
USA
26022 Posts |
Posted - 01/05/2005 : 13:46:30 [Permalink]
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quote:
Originally posted by filthy
As for recent evolution, we are taller, on the average. And this in just the last, couple of thousand years. An adult male at the time of Jesus might have been only 5'4'' to 5'6'' tall. This can also be seen in medevale suits of armor as well -- those guys were small! Few, modern men could fit into one.
It's been successfully argued that this simple change in height is not evolutionary, but simply a result of better general nutrition and health in children. And a 5'4" adult height is not so rare as to be well outside the "bell curve," especially when smaller, non-technological populations are included.
Anyway, with Chaloobi's post I also must disagree. Natural selection is but one method whereby populations evolve. Once a population becomes very large, and consistently interbreeds (as with humans, armed with airplanes), natural selection itself loses much of its power. But other evolutionary forces, especially upon traits which confer no selection pressure, continue to function.
"Without natural selection, there is no evolution" is a strict Darwinian idea, left behind by science decades ago.
Also, given the massive amount of genetic diversity among humans, it would be nearly impossible for evolution to not be occuring. Take a look around, and witness the fact that we are far from living in a world of clones. |
- Dave W. (Private Msg, EMail)
Evidently, I rock!
Why not question something for a change?
Visit Dave's Psoriasis Info, too. |
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BigPapaSmurf
SFN Die Hard
3192 Posts |
Posted - 01/05/2005 : 13:59:31 [Permalink]
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| I feel the same way, but I know we evolve no matter what (safe to say we wont be 3 eyed anytime soon, In this thread we discussed it. |
"...things I have neither seen nor experienced nor heard tell of from anybody else; things, what is more, that do not in fact exist and could not ever exist at all. So my readers must not believe a word I say." -Lucian on his book True History
"...They accept such things on faith alone, without any evidence. So if a fraudulent and cunning person who knows how to take advantage of a situation comes among them, he can make himself rich in a short time." -Lucian critical of early Christians c.166 AD From his book, De Morte Peregrini |
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Ricky
SFN Die Hard
USA
4907 Posts |
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filthy
SFN Die Hard
USA
14408 Posts |
Posted - 01/05/2005 : 14:51:09 [Permalink]
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quote:
It's been successfully argued that this simple change in height is not evolutionary, but simply a result of better general nutrition and health in children. And a 5'4" adult height is not so rare as to be well outside the "bell curve," especially when smaller, non-technological populations are included.
But 5'4'' is still well below average in industralized countries. Diet is a factor, although medieval noble's diets were fully as varied as our own, perhaps more so, but I think that is an over simplifaction. There are other factors involved, such as the previously mentioned selection by females. The few remaining, hunter/gatherer societies, such as the Amazonian indians who until recently, did not lead a hard-scrabble existance, are smaller simply because the enviornment in which they live favors a smaller stature. Move them into our society, and within some generations, don't ask how many -- I don't know, they too, might increase in size. Much of that increase would be due to adapting to the society and picking up it's mores.
We are the product of our enviornment, all of that enviornment. Eskimos, for example, tend to be fairly short and stocky of build, the better to conserve body heat. Their natural diet, pinniped and whale meat and blubber often consumed raw, as well as fish both dried and fresh, and the like, would not be healthy fare for us. But it works very well for them, in one of the harshest climates on earth.
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"What luck for rulers that men do not think." -- Adolf Hitler (1889 - 1945)
"If only we could impeach on the basis of criminal stupidity, 90% of the Rethuglicans and half of the Democrats would be thrown out of office." ~~ P.Z. Myres
"The default position of human nature is to punch the other guy in the face and take his stuff." ~~ Dude
Brother Boot Knife of Warm Humanitarianism,
and Crypto-Communist!
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Dave W.
Info Junkie
USA
26022 Posts |
Posted - 01/05/2005 : 17:31:19 [Permalink]
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quote:
Originally posted by filthy
But 5'4'' is still well below average in industralized countries. Diet is a factor, although medieval noble's diets were fully as varied as our own, perhaps more so, but I think that is an over simplifaction.
Nutrition and health, filthy. While noble diets centuries ago were, indeed, rich and varied, there were lots more simple childhood diseases which could, indeed, "stunt your growth."
Actually, both you and I may be falling prey to an old myth. Here's a PDF file which goes into this stuff in detail for England, describing a height difference between Medieval and modern English males of about an inch. The detailed discussion begins on page 12. And then, later on:Adult height results from a genetic potential modified by infant and childhood environmental influences, including diet, living conditions and frequent disease, often grouped under the heading of “nutritional status”. Although the heights of an individual's relatives provide some guide to the genetic height potential of an individual, the genetic variation built into sexual reproduction precludes knowing (yet) the genetic height potential of any individual. But genetic influences average out in a stable population, and genetic potential does not change significantly in the span of even several hundred years. So in a stable population over time, genetic factors are constant, leaving only average nutritional status of children and adolescents as the variable that significantly affects the average adult height of the population. This is true for the medieval English population, and still holds reasonably well for the Caucasian subpopulation in England through the last quarter of the 20th century... Seems to be highly referenced.quote:
There are other factors involved, such as the previously mentioned selection by females. The few remaining, hunter/gatherer societies, such as the Amazonian indians who until recently, did not lead a hard-scrabble existance, are smaller simply because the enviornment in which they live favors a smaller stature. Move them into our society, and within some generations, don't ask how many -- I don't know, they too, might increase in size. Much of that increase would be due to adapting to the society and picking up it's mores.
We are the product of our enviornment, all of that enviornment. Eskimos, for example, tend to be fairly short and stocky of build, the better to conserve body heat. Their natural diet, pinniped and whale meat and blubber often consumed raw, as well as fish both dried and fresh, and the like, would not be healthy fare for us. But it works very well for them, in one of the harshest climates on earth.
Actually, there are claims (I'm not sure how solid they are) that taking people away from their "natural" diets and feeding them the standard "Western" fare generates rates of heart disease just as high as ours, without need of intervening generations (in other words, it happens to those people). This would simply indicate that the "Western" diet isn't suitable for anyone.
But back to stature: think of, say, the Andean and/or Himillayan people, and how the men (at least) tend to be barrel-chested, presumably in adaptation to the low oxygen levels. I'm saying that if they had children who were born and raised at sea level, the kids wouldn't be barrel-chested as adults, as it's not an evolutionary adaptation, but instead a developmental adaptatio |
- Dave W. (Private Msg, EMail)
Evidently, I rock!
Why not question something for a change?
Visit Dave's Psoriasis Info, too. |
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filthy
SFN Die Hard
USA
14408 Posts |
Posted - 01/05/2005 : 19:06:47 [Permalink]
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You are right, of course. But I never said that any sort of evolutionary change would occur in an individual. We both know that that doesn't happen. A favorable mutation might show up, but it would be meaningless if it couldn't be absorbed into the population over generations.
quote:
But back to stature: think of, say, the Andean and/or Himillayan people, and how the men (at least) tend to be barrel-chested, presumably in adaptation to the low oxygen levels. I'm saying that if they had children who were born and raised at sea level, the kids wouldn't be barrel-chested as adults, as it's not an evolutionary adaptation, but instead a developmental adaptation to the environment. Likewise, I would expect that if a couple from downtown LA moved to a spot 10,000 feet up and then had a child, the kid would develop the large-lunged adaptation, too.
Such rapid changes (single generation) aren't indicative of an evolutionary process, but instead are simply developmental responses to the environment during gestation, infancy and adolesence.
But I will state that if you move an Eskimo couple to LA (and if the climate, smog, and the alledged food didn't poison them), their offspring would be built like any fire plug, an image of their parents. And assuming a population was hauled down to LA, for who knows what perverse reason, it would be many generations, but they would eventually come to be built rather like their neighbors -- even ruling out intergrading with native LAers. Slimmer and a bit taller would work better in such an environment, as the requirments of the southern city are vastly different from those at the top of the world.
As an interesting side note, the American and South American Indians had a vastly better diet and were generally healthier than the European colonists, but they succumbed to diseases that those colonists simply shrugged off; measles etc. No resistance to them and no time to develop any. Evolution in microcosm I think.
Which brings up an interesting question: today, our children are vaccinated against everything vaccinatable. What would happen to the immediate future generations if those medicines ceased to exist? Would they be more succeptable to disease due to no natural resistance? And how many generations would be required for a resistance to be built up?
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"What luck for rulers that men do not think." -- Adolf Hitler (1889 - 1945)
"If only we could impeach on the basis of criminal stupidity, 90% of the Rethuglicans and half of the Democrats would be thrown out of office." ~~ P.Z. Myres
"The default position of human nature is to punch the other guy in the face and take his stuff." ~~ Dude
Brother Boot Knife of Warm Humanitarianism,
and Crypto-Communist!
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chaloobi
SFN Regular
1620 Posts |
Posted - 01/05/2005 : 19:44:25 [Permalink]
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quote:
Originally posted by Ricky
quote:
We're just breeding like rabbits but there's no wolves to eat the slow runners before they have children. So to speak.
I would just like to point out that in that senario, the rabbits would over populate their enviornment, eat up all the food, then die of starvation.
If such a thing would occur with humans, natural selection would strongly come into play.
The cats, hawks and cars get them. My dog got one last summer. I've gotten several with my own car. (Rabbits, that is!) |
-Chaloobi
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chaloobi
SFN Regular
1620 Posts |
Posted - 01/05/2005 : 19:47:18 [Permalink]
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quote:
Originally posted by Dave W.
<snip> but how much they overlapped.
I've read a little about the height thing and it is diet. An interesting factor, the 'short races' like most Asians, when they immigrate to America actually grow to the height of the average American after several generations. It's a nutrition thing. |
-Chaloobi
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chaloobi
SFN Regular
1620 Posts |
Posted - 01/05/2005 : 19:51:55 [Permalink]
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quote:
Originally posted by filthy
Um, pretty broad statment, 'loobi. <snip>
By design. :)
quote:
<snip> Therefore, any mutation that might benefit us under other conditions simply never needed to be selected.
I couldn't disagree with you more. There's a lot more in the environment putting selective pressures on a species than climate. Indeed, climate is one of the characteristics of our environment that we can almost wholly adapt to with the use of our brains - via use of tools, clothing, etc.
quote:
As for recent evolution, we are taller, on the average. And this in just the last, couple of thousand years. An adult male at the time of Jesus might have been only 5'4'' to 5'6'' tall. This can also be seen in medevale suits of armor as well -- those guys were small! Few, modern men could fit into one.
Of course, while this increase in higth, largly selected for by our females who themselves became taller as a genetic result, is ok today, it could become a serious disadvantage in a changed environment.
As noted already, this is actually a nutrional thing. Our genes arn't changing for more height.
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-Chaloobi
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chaloobi
SFN Regular
1620 Posts |
Posted - 01/05/2005 : 19:54:40 [Permalink]
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quote:
Originally posted by Dave W.
Anyway, with Chaloobi's post I also must disagree. Natural selection is but one method whereby populations evolve. Once a population becomes very large, and consistently interbreeds (as with humans, armed with airplanes), natural selection itself loses much of its power. But other evolutionary forces, especially upon traits which confer no selection pressure, continue to function.
"Without natural selection, there is no evolution" is a strict Darwinian idea, left behind by science decades ago.
Also, given the massive amount of genetic diversity among humans, it would be nearly impossible for evolution to not be occuring. Take a look around, and witness the fact that we are far from living in a world of clones.
Please elaborate on the other methods of evolution occurrng in the human species today. You should know better than to make such a statement without some technical goodies attached. I'd first like you to explain how a mutation or a genetic change of any kind in an individual can become prevalent in a population without being selected for (or against). |
-Chaloobi
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| Edited by - chaloobi on 01/05/2005 19:55:00 |
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chaloobi
SFN Regular
1620 Posts |
Posted - 01/05/2005 : 19:58:02 [Permalink]
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quote:
Originally posted by BigPapaSmurf
I feel the same way, but I know we evolve no matter what (safe to say we wont be 3 eyed anytime soon, In this thread we discussed it.
I completely disagree. Without natural selection to spread a genetic change throughout the gene pool, it will not become commonplace in the species. Now, you can make the argument that my assertion there are no selectors operating now on the human species is incorrect, and you'd probably be right, but evolution does not occur without selectors that give one individual a breeding advantage over others. If anyone knows of a mechanism that can do this other than natural selection, I'd like to hear about it with some good links. |
-Chaloobi
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