That's not evidence for genetic change because it is well known that environmental factors alter average height and these factors are known to have changed.
Evolution, yes but how?
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That's not evidence for genetic change because it is well known that environmental factors alter average height and these factors are known to have changed.
We can see evolution today in humans; wisdom teeth for example, only some people have them now, they are slowly being phased out due to no longer being used.
That would be Lamarkism.
For natural selection to remove Wisdom teeth it would have to be a selective advantage not to have them.
Well you've clearly misunderstood what I said as I made that same statement in the first sentence of my post.
Evolution doesn't do anything. It describes a process where you have a species that exists in many slight variations and the environment will favour certain variations. Now if you're saying that society doesn't change the environment (therefore which variations are favoured) then that's obviously nonsense...
Yes that would be for natural selection, but would genetic drift over hundreds and thousands of years perhaps be sufficient? That was what he was implying - there is no use and it is subject to drift, which is fundamentally different from being selected against.
Meh I'm itching to get stuck in on this thread but I can't
Yes, you're correct. If so, I misunderstood -sorry XeNoN89.
Loss of neutral characters through genetic drift does take a very long time but it will happen eventually.
So average height was lower hundreds of years ago purely because diet/nutrition was so bad that growth was stunted and potential not realised - no selection pressure and no genetic change at all? Well maybe you're right - I certainly can't claim to really know. But then why did I get so much less action in my youth in night clubs, etc than all my tall ugly mates??
Caporegime
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So average height was lower hundreds of years ago purely because diet/nutrition was so bad that growth was stunted and potential not realised - no selection pressure and no genetic change at all? Well maybe you're right - I certainly can't claim to really know. But then why did I get so much less action in my youth in night clubs, etc than all my tall ugly mates??
Are you really ugly?
There's plenty of good evidence that diet and disease impact height. It is also extraordinarily unlikely that, even if there has been some selective pressure for taller people, it could have produced the increases seen in the short timescales involved.
(Oh, and BTW, height was lowest around 200 years ago during the industrial revolution when people were living in truly awful conditions - the average lifespan in UK cities dropped to about eighteen years old)
The environmental factor interpretation is also supported by the fact that the children who've moved from places with poor nutrition to countries with good nutrition have seen instant increases in height compared to their parents
But then why did I get so much less action in my youth in night clubs, etc than all my tall ugly mates??
It's probably down to personality and confirmation bias.
So average height was lower hundreds of years ago purely because diet/nutrition was so bad that growth was stunted and potential not realised - no selection pressure and no genetic change at all? Well maybe you're right - I certainly can't claim to really know. But then why did I get so much less action in my youth in night clubs, etc than all my tall ugly mates??
If you look at the industrial revolution, you can see that due to poor diet, physical size and fitness decreased in urban environments, bucking the trend of increasing size.
Industrial revolution had quite a large impact on society, certainly in terms of the physical health of the people in it. My ex was (maybe still is?) an osteo-archaeologist (studies human remains, for you lay-people). There is a great correlation of diet to health of the population, resistance to disease etc, even leaving out some of the advances in medicine, the impact of the general stature (broken down into various age and sex groups) is closely related to the health of the population statistics.
In short, many diseases leave permanent records of themselves behind in the bones. Examples are of purely nutritional deficiency, like rickets, to other social diseases, like syphilis, then there's all of the physical environmental factors like what kind of labour the person did, leading to conditions like osteo arthritis/porosis (sp?) indicative of extreme physical labour (one early example is the typical roman centurion; despite his relatively healthy life style for the time, old soldiers have a marked incidence of spinal and disk pproblems as a resuly of marching with 90lb packs and armour for much of their lives. Same goes for the old english longbowman - a lifetime of training biases the musclature/ligaments and their attachments to the skeleton that make them easily identifiable, relatively speaking, from an archaeological point of view).
But getting back to how people have changed as a result of better diet and health over the centuries, as a rule, we are now longer lived, taller, and less prone to illnesses all of which has lead to a physically more robust (though perhaps that's not the right word to use here) body type - body shape and stature have all changed as a result of better diet and health, factors that were previously limited by hardship and disease.
This is an evolution of a sort, but not necessarily a natural one. In this, humans are unique on the planet; of all the species, we are the only ones really capable of making our environment evolve to suit us. In the natural world, species change to reflect the conditions in which they live.
These key differences are very important when you consider the different aspects of what we generally term 'evolution' and how it effects us and the world. Whereas some animals react to the environment and either prosper of become extinct, humans have left behind the natural evolution and turned the tables by adapting their environment to suit their needs. Could this cause problems in the long term evolution of our species and its ability to adapt to changing circumstances beyond those we have the ability to directly influence?
Here is where the arguments, that human beings have reached a self imposed plateau caused by our own manipulation of our surroundings, begin - we can only evolve to suit our own changes, and as we pretty much change the environment to suit ourselves currently, this could leave the opportunities for genetic development to become far more subtle and long term (perhaps than even what I have termed 'natural evolution') so as to be almost undetectable.
Well, that's one idea, certainly.
But evolution in the natural world is very much a process of biology changing to suit environmental factors like climate, food, predators, disease and so on.
Coming back to the industrial revolution for a last word, there is a particular moth that adapted itself in colouring/camouflage as a result of buildings becoming darkened with soot and smog from heavy industry. It became of darker colouring as a species, whist the lighter coloured moths of its species were removed from the business of breeding by predation due to not being able to successfully camouflage itself, so darker coloured moths bred and became the majority. However, since the advances in industry and latterly, the regulations for clean air and factory emissions, the balance of dark to light coloured moths has swung back the other way. All as a process of natural evolution where the breeding stock was heavily influenced by environmental factors in as short a time-scale as one or two hundred years.
It would appear that a species longevity (certainly in the natural world) is determined by its adaptability and its mutability. Those who failed to adapt became extinct. What this says for a species that has stepped out of the bounds of natural evolution to craft the world as he sees fit, is difficult to say with any certainty, but the question of our own evolutionary flexibility as modern humans, as products of our own ingenuity and guile, is either entirely transcendent of the bounds of natural evolution (and I don't think we are quite there yet), or we are yet on the cusp of being able to control our own development as a species, which leaves us confident of our own arrogance to change the world and by extension ourselves, but, however, we still remain quite vulnerable to factors that are still beyond our control at this stage in our mastery of science and biology.
I'm not down with the particulars of the detailed science, but the arguments in their broader sense are already relatively well defined, enough at least for me to pontificate from time to time.
ooh, that went on a bit longer than I intended tl:dr
In short, many diseases leave permanent records of themselves behind in the bones. Examples are of purely nutritional deficiency, like rickets, to other social diseases, like syphilis, then there's all of the physical environmental factors like what kind of labour the person did, leading to conditions like osteo arthritis/porosis (sp?) indicative of extreme physical labour (one early example is the typical roman centurion; despite his relatively healthy life style for the time, old soldiers have a marked incidence of spinal and disk pproblems as a resuly of marching with 90lb packs and armour for much of their lives. Same goes for the old english longbowman - a lifetime of training biases the musclature/ligaments and their attachments to the skeleton that make them easily identifiable, relatively speaking, from an archaeological point of view).
But getting back to how people have changed as a result of better diet and health over the centuries, as a rule, we are now longer lived, taller, and less prone to illnesses all of which has lead to a physically more robust (though perhaps that's not the right word to use here) body type - body shape and stature have all changed as a result of better diet and health, factors that were previously limited by hardship and disease.
This is an evolution of a sort, but not necessarily a natural one. In this, humans are unique on the planet; of all the species, we are the only ones really capable of making our environment evolve to suit us. In the natural world, species change to reflect the conditions in which they live.
These key differences are very important when you consider the different aspects of what we generally term 'evolution' and how it effects us and the world. Whereas some animals react to the environment and either prosper of become extinct, humans have left behind the natural evolution and turned the tables by adapting their environment to suit their needs. Could this cause problems in the long term evolution of our species and its ability to adapt to changing circumstances beyond those we have the ability to directly influence?
Here is where the arguments, that human beings have reached a self imposed plateau caused by our own manipulation of our surroundings, begin - we can only evolve to suit our own changes, and as we pretty much change the environment to suit ourselves currently, this could leave the opportunities for genetic development to become far more subtle and long term (perhaps than even what I have termed 'natural evolution') so as to be almost undetectable.
Well, that's one idea, certainly.
But evolution in the natural world is very much a process of biology changing to suit environmental factors like climate, food, predators, disease and so on.
Coming back to the industrial revolution for a last word, there is a particular moth that adapted itself in colouring/camouflage as a result of buildings becoming darkened with soot and smog from heavy industry. It became of darker colouring as a species, whist the lighter coloured moths of its species were removed from the business of breeding by predation due to not being able to successfully camouflage itself, so darker coloured moths bred and became the majority. However, since the advances in industry and latterly, the regulations for clean air and factory emissions, the balance of dark to light coloured moths has swung back the other way. All as a process of natural evolution where the breeding stock was heavily influenced by environmental factors in as short a time-scale as one or two hundred years.
It would appear that a species longevity (certainly in the natural world) is determined by its adaptability and its mutability. Those who failed to adapt became extinct. What this says for a species that has stepped out of the bounds of natural evolution to craft the world as he sees fit, is difficult to say with any certainty, but the question of our own evolutionary flexibility as modern humans, as products of our own ingenuity and guile, is either entirely transcendent of the bounds of natural evolution (and I don't think we are quite there yet), or we are yet on the cusp of being able to control our own development as a species, which leaves us confident of our own arrogance to change the world and by extension ourselves, but, however, we still remain quite vulnerable to factors that are still beyond our control at this stage in our mastery of science and biology.
I'm not down with the particulars of the detailed science, but the arguments in their broader sense are already relatively well defined, enough at least for me to pontificate from time to time.
ooh, that went on a bit longer than I intended tl:dr
Last edited:
Soldato
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Well we're getting progressively better looking, since nobody will have sex with the ugly people
Soldato
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Let's evolve, let the chips fall where they may.
Well we're getting progressively better looking, since nobody will have sex with the ugly people
Alcohol has levelled the playing field for many years!
Soldato
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I never get "beer goggles", unfortunately neither do the ladies I talk to.
<goes back to Skyrim>
Woo, post catch up time... the time off has allowed me to articulate my thoughts.
However, it's not necessarily a good indicator of fitness for humans, which I will explain below.
I don't think so. I understand exactly what you are saying (which is a generally extremely sensible approach to evolutionary theory), so please hear me out.
Humans are very unlike most animals in that they have a very unique set of selective pressures, mainly in the sense that those pressures are not oppressive. Having bad eye sight or being physically weak is not necessarily going to impair your reproductive success, unlike in most animals. Selection for viability is pretty much obsolete. People are more likely to succeed by providing excessively for their children and giving them full attention, which is necessary since human children are so weak, resulting in monogamy. Monogamy in itself limits how many children a man can have. A man could have hundred and hundreds of children if he slept around, but he does not. Why? Why is this not selected for? Why do we all instinctively think having many children is a bad idea?
The reason is the social environment and corresponding behavioural instincts that humans live with which stem from monogamy within an intelligent species. This has in effect 'stunted' our classical understanding of evolution - the selfish genes no longer act strictly to ensure that we have many, many children. Instead, the genes wish to exist in individuals that have the maximum possible potential for reproductive success. We can see this behavioural trait highly influenced by genetics numerous times in human populations:
- men generally have a preference for women with relatively large breasts
- men generally have a preference for women with blonde hair
- woman generally have a preference for taller men
A man that has a child with a large breasted women is evolutionary 'winning', because his female children will inherit the large breasted genes and his male children will inherit both the attraction to larger breasts. Both the male and female children will also (to extents) pass on the attraction to breasts and the genes that give a larger breasted phenotype. This is classic sexual selection. Yet our behaviour in modern western society stunts the further propagation of these genes - monogamy and the resources needed to raise children preclude it.
There is clear sexual selection going on within humans. We are all generally attracted to the same things, probably because they represent sexual dimorphism (we instinctively associate height with men and breasts with women). So it is sensible to deny this because we need to see evidence of more grandchildren? Not really, at least not with these traits - with the complexity of human social interaction and the lack of viability selection, it doesn't seem to be a very clear indicator of selected traits at all.
However, some things are clear. We all wish to mate with attractive people - the evolutionary reason for this is because our genes want attractive children. The reason for this is because this further increases the chance of those genes being passed on, despite the fact our social behaviour is (relatively) restrictive in preventing the wide spread of these genes. Height increase in men in recent years has obviously been due to improvements in health, but what about the increase in blonde hair over the last 2000 years? Why do so many girls dye their hair blonde? Why is their a stigma against short men?
In light of all of this, I think it is very fair to say that height is being selected for in men, certainly in the sense that women want to ideally mate with men that have such a phenotye. It is not the number of grandchildren that is important, but the ability of the children to potentially have as many children as possible, by having the combination of genes that are the most attractive.
I hope this has gone some way to settle our discrepancies
Indeed, I made the same statement in this post:
However, it's not necessarily a good indicator of fitness for humans, which I will explain below.
I would prefer to say that something like attractiveness will only get evolutionary selected for in they result in a higher number of sexually successful grandchildren, but I assume that's what you meant. Again, this is somewhat limited in scope for some populations in humans, which I will go into below.
I don't think so. I understand exactly what you are saying (which is a generally extremely sensible approach to evolutionary theory), so please hear me out.
Humans are very unlike most animals in that they have a very unique set of selective pressures, mainly in the sense that those pressures are not oppressive. Having bad eye sight or being physically weak is not necessarily going to impair your reproductive success, unlike in most animals. Selection for viability is pretty much obsolete. People are more likely to succeed by providing excessively for their children and giving them full attention, which is necessary since human children are so weak, resulting in monogamy. Monogamy in itself limits how many children a man can have. A man could have hundred and hundreds of children if he slept around, but he does not. Why? Why is this not selected for? Why do we all instinctively think having many children is a bad idea?
The reason is the social environment and corresponding behavioural instincts that humans live with which stem from monogamy within an intelligent species. This has in effect 'stunted' our classical understanding of evolution - the selfish genes no longer act strictly to ensure that we have many, many children. Instead, the genes wish to exist in individuals that have the maximum possible potential for reproductive success. We can see this behavioural trait highly influenced by genetics numerous times in human populations:
- men generally have a preference for women with relatively large breasts
- men generally have a preference for women with blonde hair
- woman generally have a preference for taller men
A man that has a child with a large breasted women is evolutionary 'winning', because his female children will inherit the large breasted genes and his male children will inherit both the attraction to larger breasts. Both the male and female children will also (to extents) pass on the attraction to breasts and the genes that give a larger breasted phenotype. This is classic sexual selection. Yet our behaviour in modern western society stunts the further propagation of these genes - monogamy and the resources needed to raise children preclude it.
There is clear sexual selection going on within humans. We are all generally attracted to the same things, probably because they represent sexual dimorphism (we instinctively associate height with men and breasts with women). So it is sensible to deny this because we need to see evidence of more grandchildren? Not really, at least not with these traits - with the complexity of human social interaction and the lack of viability selection, it doesn't seem to be a very clear indicator of selected traits at all.
However, some things are clear. We all wish to mate with attractive people - the evolutionary reason for this is because our genes want attractive children. The reason for this is because this further increases the chance of those genes being passed on, despite the fact our social behaviour is (relatively) restrictive in preventing the wide spread of these genes. Height increase in men in recent years has obviously been due to improvements in health, but what about the increase in blonde hair over the last 2000 years? Why do so many girls dye their hair blonde? Why is their a stigma against short men?
In light of all of this, I think it is very fair to say that height is being selected for in men, certainly in the sense that women want to ideally mate with men that have such a phenotye. It is not the number of grandchildren that is important, but the ability of the children to potentially have as many children as possible, by having the combination of genes that are the most attractive.
I hope this has gone some way to settle our discrepancies
I blame the Christians, they destroyed our native religions...