Current Human Evolutionary 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?

[labelwench]

An interesting idea for a thread, Moontanman.

 

I have been contemplating for a while now that technology has been a factor in our evolution for some time, especially the internet and connectivity technologies for they allow us to share information at an ever increasing pace.

 

Those who are able to read, write and utilize these technologies shall have an ever increasing advantage over those who either do not have access to or are unable to use it because of learning challenges.

 

'Knowledge is power.' Sir Francis Bacon.

 

With today's technology and science we can control when (and by whom) we wish to give birth. Selective breeding has been utilized with a number of species, notably horses and dogs. With humans now able to practice selective breeding, this undoubtedly will have an influence on what characteristics we select for and should result in some different outcomes than the previous rape, pillage and plunder tactics of previous generations.

 

Another interesting influence may be the fact that religion is gradually losing converts to atheism.

 

We may yet evolve into a species that is capable of critical thinking.

 

[belovelife]

interesting topic for sure

 

here is an interesting thing,

 

autistics sometimes have larger amigdala

 

this is certain autistics

they have increased sense of hearing , and flight or fight sense

 

one drew a picture of newyork from a 20 minuit flight

 

amazing

 

the the movie rainman

 

 

could this be an evolutionary step ?

and if it is, are we smart enought to teach them,

 

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also, i think part of the evolutionary track is instigated by nature,

 

so as you interact, you change, in modern times, we stray away from these interaction

 

( drinking water from a stream, or eating food from the ground )

 

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mainly, i think it has to do with teaching though

 

as we teach, and learn, we advance

 

like working out muscles, we work out the brain, which leads us farther scientifically

[CraigD]

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.

I’m in this same “almost certainly would have died before reproducing” cohort. As an infant, I had a severe staph infection of my sinuses that, prior to the introduction of penicillin in 1942, would have been practically untreatable. This is to say, had my mother or father had the same, they would likely have died of it (I was born in 1960).

 

It’s not as straightforward as it at first thought seems, I think, to conclude from these anecdotes, true, remarkable, and statistically confirmable as they are, that advances due to civilization have made genes that cause or contribute to formerly fatal childhood diseases. For one reason, civilization has produced not only medicines and therapies to treat diseases, but common conditions that cause them, especially high population density, and the sanitation and contagion issues that entails. My childhood illness is a case in point: when it occurred, my father was a physician in an urban hospital. His guess, a pretty likely one, is that despite his careful, professional hygiene techniques, he carried the bacteria that infected me from the hospital.

 

Another reason is that much of the human population doesn’t have access to modern medicine or nutrition, yet live long enough to have children. Although geographic and social barriers isolate then somewhat, this isolation is not total, so the global human gene pool receives input from essentially pre-historic condition populations.

 

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.

Recent microbiological research inform us that the “rate of human evolution” (vague as this concept is) has increased in the last 10,000 years, and continues to increase roughly proportionally to the increasing human population.

 

The traits this evolution is selecting for that have been clearly identified, however, are mostly related to diet. Essentially, we’ve selected to thrive on the foods civilized humans eat, rather than the more wild ones that prehistoric ones did.

 

A surprising finding is that, for 20,000 to 30,000 years, our heads and brains have been shrinking, by about 10%, from an average of about 1500 to 1350 cm³, although there’s no evidence that this has affected intelligence.

 

This brain size decrease is especially interesting and mysterious, because it doesn’t appear to be explainable as due to the same environmental pressures as our digestive adaptations. That is, it’s not clear that it’s due to the advantage of smaller-brained populations requiring less food per individual than larger-brained ones. The main confounding data for this explanation is that isolated human populations, such as native Australians and southern Africans, did not have great changes is diet until the last few centuries, but show the same decrease in brain size as “agricultural revolution” human populations that did.

 

(sources: Has our BIOLOGICAL EVOLUTION ended?; Human evolution, radically reappraised; The 10,000 Year Explosion; If Modern Humans Are So Smart, Why Are Our Brains Shrinking?; A growing number of scientists argue that human culture itself has become the foremost agent of biological change )

 

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?

Sounds reasonable, but until neurological and gene science can explain what behavior-predisposing traits are and aren’t heritable, I think this answers to this question can only be guesses.

 

Also, I suspect there’s less of a correlation between success of the “stay out of jail” and “reproduce” kinds than this question implies. Though only anecdotes, most of the people I know who have been in prison have children, and most of the people I know who have no and will likely not have children, have not been.

 

I have been contemplating for a while now that technology has been a factor in our evolution for some time, especially the internet and connectivity technologies for they allow us to share information at an ever increasing pace.

 

Those who are able to read, write and utilize these technologies shall have an ever increasing advantage over those who either do not have access to or are unable to use it because of learning challenges.

The education and “digital divide” of which UtR speaks is clearly a strong determiner of success of the quality of life, income, and often life expectancy kind, but, as with the “stay out of jail” kind I mentioned above, I suspect these kinds of success correlate only weakly if positively at all with the reproductive kind. “High technology” – that involving information, consumer electronics, and others in which great disparities between people of different nationalities, social classes, and personalities exist – are, I think, of little or no biological evolutionary consequence. “Low/baseline technology” – eating domestic rather than exclusively wild diets, living in fairly permanent dwellings in protective communities, etc. – are of biological evolutionary consequence, as evidenced by the physical trait changes I mention above.

 

With today's technology and science we can control when (and by whom) we wish to give birth. Selective breeding has been utilized with a number of species, notably horses and dogs. With humans now able to practice selective breeding, this undoubtedly will have an influence on what characteristics we select for and should result in some different outcomes than the previous rape, pillage and plunder tactics of previous generations.

While we humans have been able to breed ourselves selectively for practically as long as we’ve had a conscious understanding of doing it with pets and livestock, I’ve seen no compelling argument or evidence that sizable populations of us actually have. Rather, though they are not usually expressed as such, we have many cultural traditions dictating that our reproduction should be fairly haphazard, and apparently an instinctual exogenous urge, expressed as taboos against reproducing with people who strongly resemble us, and finding “exotic” people who do not sexually attractive. We also have long-running cultural traditions involving on again/off again attraction to and abhorrence of perhaps the most applied approach to human selective breeding, killing or sterilizing “undesirables” in the name of “eugenics”.

 

In short, though we humans are domesticators of animals, I think we are ourselves “wild”, in the sense that, for the most part, neither our own nor a “higher” species has effectively domesticated us by controlling our reproduction.

 

autistics sometimes have larger amigdala

 

this is certain autistics

...

could this be an evolutionary step ?

The significance of autism spectrum disorders to human evolution is interesting, especially when one speculates that the vaguely defined “big event” in human evolution – whatever it was that, after hundreds of thousands of years of anatomically modern humans “living pretty much like animals”, resulted in us developing language, technology, and all of the traits that eventually produced present day civilization – may have been the initial appearance in the population of traits that are ASD-like, ie: a predisposition to self-stimulation, idiosyncratic, ritual behavior, and increased focus on one’s inner mental life rather than one’s surroundings. It’s not too long a stretch of the imagination to imagine autistic savants be esteemed as shaman in prehistoric societies, perhaps creating the beginnings of human culture that eventually time-bound to us all.

[belovelife]

interesting

[Lancewen]

Evolutionary change is a bit more complex than this topic has covered so far. You have fairly quick changes that happen because of changes in diet, you also, have some changes that happen as a direct result of mate selection. An example of this might be the different races. But the one thing that's starting to happen now is a greater number of people are mixing the gene pool which could be a very good thing, because sooner or later the human population on this world is going to be severely stressed and some genetic combinations will fare better than others, and we will start expanding the population again with the winning gene combinations.

 

Who knows, maybe genetic engineering will provide superior gene combinations that will make up out future generations.

[belovelife]