Current human evolution pressures

[Moontanman]

Are humans evolving due to the pressures of living in large groups? I think it's pretty obvious that things like medicine are allowing people to live to be old enough to reproduce that in pre civilized times would not but does the influence of our civilization amount to a evolutionary pressure much like nature selection?

 

I know that medicine saved my life at least three times before I had children, I am sure there are many others who wouldn't lived to reproduce without modern medicine. Medicine that allows individuals to change behaviors that would other wise have crippled them socially if not saved their lives would also be an influence as well.

 

If you look back over history the behavior of the human species seems to have changed considerably. Is this change a real change in humans or is it just humans using a repertoire of behaviors we always had but were used in different ways before civilization?

 

Are we in the middle of significant evolutionary change driven by the selection pressures of our own civilization and we cannot see it because we are too confused by the forest to see the trees?

 

I think some of the possible evolutionary pressures to be considered are medicine, governments and laws, and religion.

 

Behaviors that at one time might have allowed individuals to reproduce more successfully are now more likely to result in criminal behavior and jail time other behaviors that at one time might have doomed an individual to low status and fewer reproductive opportunities might have the opposite effect in modern times.

 

Are these selection pressures considered significant or are they swallowed up by the gene pool with little or no lasting effects?

[Phi for All]

I'm not sure if this qualifies, but I think our exposure to heavy commercialization has an effect on our evolutionary paths. Natural selection would seem to be influenced by materialism, and how we look and dress is also heavily influenced by the need to sell ways to change how we look and dress.

 

The effects of governments and laws, coupled with a more global outlook, seems to be creating (at least in the US) a tendency towards conservatism, and I think we're becoming excessively so. I'm not sure if this is simply modern commercialism playing to a negative set of emotions in an attempt at control, but I can't help but think it will affect future generations.

[Moontanman]

I'm not sure if this qualifies, but I think our exposure to heavy commercialization has an effect on our evolutionary paths. Natural selection would seem to be influenced by materialism, and how we look and dress is also heavily influenced by the need to sell ways to change how we look and dress.

 

The effects of governments and laws, coupled with a more global outlook, seems to be creating (at least in the US) a tendency towards conservatism, and I think we're becoming excessively so. I'm not sure if this is simply modern commercialism playing to a negative set of emotions in an attempt at control, but I can't help but think it will affect future generations.

 

 

Do you think these things are actually based in our genes or are just behaviors we learn?

Edited September 9, 2012 by Moontanman

[jp255]

The aspect of evolution that should be considered for this debate. Differential rates of survival and reproduction between individuals. This is all that is relevant, anything which does not contribute to differential rates of survival or reproduction will not be under selection and instead will be under genetic drift (if it is a genetic factor) or will not have any effect on evolution (if it is an environmental factor).

 

Survival rates are relatively high, in first world countries at least. Medicine has played a big part in this, and the selection pressures against disease causing alleles is small (for diseases with effective treatments). It is fair to say that some genetic diseases (with very effective treatments) have low selection and are pretty much under drift.

 

Does natural selection act on civilisation? I think it does. However I think it does so by, non-genetic mechanisms, by culture. When I say non-genetic I understand there are obviously genetic requirements before culture can arise, I mean that the variance observed in people's taking to the culture is primarily enviornmental rather than genetic. In other words, if there were a heritability study on culture it would probably be mostly explained by the environment and the value for genetic contribution would be low. This is only a suggestion, but I think it is likely because I don't think that condom use is genetically programmed, or that celebrating birthdays is programmed, or that most/if any traditions/cultural behaviours are genetically programmed. This area of study is known as memetics, where a meme is thought of as a "unit of culture" that is heritable but not constrained to DNA/replicator.

 

For example: let's consider religion and it's potential to contribute to evolution. Can natural selection work through religion? I think it can primarily through the reproduction aspect of natural selection. Last I checked some religions don't agree with use of contraceptives, I apologise if this is wrong. In comparison to a culture where this use of contraceptive is commonplace, and assuming that every other factor is the same, this religion/culture should in theory lead to a significantly higher rate of reproduction amongst those who do not use contraceptives. Thus the idea/culture of religion (and not using contraceptives) is subject to natural selection, however this assumes it must be able to survive or be heritable.

 

 

In theory an idea such as this (not using contraception) does lead to natural selection (in a poipulation where some people do not use contraception and some do), when one assumes that the idea is heritable, and that all other factors are equal. The idea itself will be overrepresented in the population and gradually rise in frequency and also the genes of that person will be overrepresented in the population and rise in frequency. Proving it in reality is obviously difficult, there are so many other factors at play. The potential for civilisation/culture/religions to cause gene frequency changes by altering reproduction rates (and also survival) is there though.

 

Do you think these things are actually based in our genes or are just behaviors we learn?

 

There are genetic requirements, but I think that the genetic contribution to individual variance regarding cultural type behaviour is very small. Imagine a heritability study regarding the culture of not using contraception. MZ and DZ twins that grow up in families which are not pro contraception, what do you think the discordant rates will be? do you they will differ by a large amount between MZ and DZ? That genetics can partly explain why one twin decides condom usage is bad and the other doesn't? I'm not so sure genetics can explain much of an individuals opinion.

[dmaiski]

(TLDR read only the bottom, (you fit into the “young” bracket))

 

 

 

 

i would have to say none and not applicable

(at least for 1st world countries)

evolution requires a stable population exposed to an environment, where all individuals are in competition with each other

 

1 our population is expanding, and we do not let children die (actually our safety first mentality dosen't let anyone die, even the terminally stupid)

 

2 our ability to travel, let alone our rate of technological progress means we have moved through at least 1 new environment every decade, this is not conducive to natural selection

also in the last 100 years our environment did a flip, from where Brawn was rewarded, to an environment where intelligence is paramount, and no paradisical labour is needed at all

(1900-1910, ww1, 1920-1930, great depression, ww2, 1940-60, 60-70(hippy, ect), cold war, 80-Y2k(dawn of computing), 2k-present(micro-computing age), just to list a few)

 

3 humans are not actively in competition with each other over resources, living space, or mates

 

this results in no directional evolution to a set points

it douse though, on a large scale, encourage breeding to be limited to the "class system", the ceo's daughter wont marry a bum off the street, the blue collar will keep to the blue collar's, and the white collar to the white collar's (if this continues for the next 1000 years we may even see the emergence of a new species)

 

unfortunately, were out of time and the game is almost to the end for human evolution

i would be extremely surprised if large scale acceptance of genetic engineering and cybernetics do not occur within the next century (and quite disappointed because this would mean the human race ran off the cliff without building a bridge first (means H.sapien is extinct by this point)

 

 

 

 

current pressures(as of right this moment, in order from most to least):

 

in older individuals(25+): general intelligence, prowesses with a smart phone, fecundity, literacy, knowledge, physical beauty,

(literally a well read good looking ass hole with eidetic memory and a very willing willy(and the female equivalent))

 

in younger individuals: wealth, prowesses with a smart phone, fecundity, physical beauty,

("romance is dead", a very fitting description)

 

looking at this you could say we are breeding a legion of brain-dead drones

(no worries give it 10 years and all of these will change once again)

 

 

[jp255]

current pressures(as of right this moment, in order from most to least):

in older individuals(25+): general intelligence, prowesses with a smart phone, fecundity, literacy, knowledge, physical beauty,

(literally a well read good looking ass hole with eidetic memory and a very willing willy(and the female equivalent))

 

in younger individuals: wealth, prowesses with a smart phone, fecundity, physical beauty,

("romance is dead", a very fitting description)

 

 

I am not so sure that some of these traits actually are under selection. It is fair to say that survival to reproductive age is not of much of a selection pressure to human populations (first world of course). So genetic factors which contribute to increased survival won't be under much selection, as the probability anyone individual in the population reaches reproductive age is already very high. Therefore any strong natural selection going on is likely to be occuring on factors which affect the number of offspring an individual has. So I am doubtful that those traits are under selection. You could argue that these might be under sexual selection, but sexual selection in humans going on today is not just about mate choice anymore (because contraception use is commonplace) but rather who you decide to have children with. Basically, physical beauty could only really be under selection if attractive people have more children than the average individual. For this reason, I am not so sure there is much sexual selection currently going on.

 

I think that the most likely factors under selection today are those which contribute to population variance in average number of children an individual has. Some people do not have children despite being fertile and heterosexual, any factor contributing to this behaviour will be selected against. Vice versa to those that have more children than the population average. These factors can be genetic and environmental (culture and civilisation can be under selection).

[dmaiski]

korn evolurion video

somewhat fitting, though general IQ has increased(if you use non standardized test groups, really bad methodology with no understanding of how you measure IQ and why its a bell curve)

 

high iq/wealth families avarage 1.5 children

low iq/wealth families avarage 5 children

 

perfect recipe for evolution (in a not so smart direction) or speciation (again this would only happen long after humanity has died out or took charge of its own evolution by GM and stopped mucking about with half measures)

 

 

[NIF]

a few good points have been put forward concerning 'cultural trends' and 'interlectual prowess' influencing natural selection. However I don't think anyone has touched on the other half of evolution: mutation rates.

 

Kitchen microwaves, mobile phones, Radio transmiters, remote central locking, TV screens and Computer monitors, iPods, anything WiFi / BluTooth / wireless... and the list just goes on...

 

it has been Proven that radiation (including low level radio waves) up the mutation rate.

Here is one such study done on the Fukushima area.

[dmaiski]

this would only be valid if you are habitualy sticking your testies in the microwave when its cold outside

[NIF]

this would only be valid if you are habitualy sticking your testies in the microwave when its cold outside

incorrect. speed warming your testies may result in a noticable amount of mutations within a single generation, but isn't evolution all about the 'gradual mutations over millions of years'?

 

just because you children don't have 3 heads, doesn't mean that they havn't had some mutation.

[jp255]

Dmaiski was just pointing out that germline mutations are the only relevant mutations when evolution is considered. Still, I'm not sure how significant that argument is. I'd imagine the mutation rate increase from such factors to be fairly low.

[Bill Angel]

...

I think some of the possible evolutionary pressures to be considered are medicine, governments and laws, and religion.

...

Are these selection pressures considered significant or are they swallowed up by the gene pool with little or no lasting effects?

I can see situations where selection pressures have been significant. Native Americans developed their own systems of medicine, government, and religion in isolation from Europeans. When the two cultures met, the European systems prevailed, to the detriment of Native American culture and population. But looking at the issue of genetics, I don't know how much difference there actually is between the European genotype and the Native American genotype.

[dmaiski]

I can see situations where selection pressures have been significant. Native Americans developed their own systems of medicine, government, and religion in isolation from Europeans. When the two cultures met, the European systems prevailed, to the detriment of Native American culture and population. But looking at the issue of genetics, I don't know how much difference there actually is between the European genotype and the Native American genotype.

 

those are socio economic and technological advances, and warfare with superior weapons, tactics, and numbers, mixed with new, potent diseases that were developed in the cramped environments of cities, not really evolutionary pressure

 

 

[jp255]

I can see situations where selection pressures have been significant. Native Americans developed their own systems of medicine, government, and religion in isolation from Europeans. When the two cultures met, the European systems prevailed, to the detriment of Native American culture and population. But looking at the issue of genetics, I don't know how much difference there actually is between the European genotype and the Native American genotype.

 

Civilization changes like that can only be under local selection (one state/country/county) if the civilization change alters the reproduction/survival rates of a proportion of individuals in the population (less than 100%). On a global scale (when considering humans as one big population) civilization changes could potentially contribute to natural selection, if civilization contributes to reproductive/survival variance among countries. For example, if civilization places a limit on reproduction (1 child only), and other countries are reproducing at a greater rate then this contributes to allele frequency changes (and is a selection pressure) when considering human populations as a global population (and assuming survival rates are the same).

 

Basically, anything that contributes to population variance (on global or local population levels) in average number of children that reach reproductive age is under selection. It is, for the most part, speculation as to what factors contribute.

[Jens]

high iq/wealth families avarage 1.5 children

low iq/wealth families avarage 5 children

 

I agree it is a not so nice trend.

 

Part of this is caused by incompatiblity between a good job and having children for women.

In France politicians took some measures. For example:

- Much better organized childcare than in most other European countries from an early age (good opening hours during the workday and over the year)

- A lot of tax reductions (and not a fix rate) from the 3rd child on, so that you really do not have to lower your living standard at least with the 3rd child.

- Cheaper to buy houses / appartments in areas where there is work (compared to Germany)

 

This actually had an effect (compared to Italy for example).