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Future of human evolution?

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  • 06-12-2010 3:30pm
    #1
    Banned (with Prison Access) Posts: 7,225 ✭✭✭


    Another speculative thread.

    Basically, what do you think the trend for human evolution will be? Have we stopped evolving due to the fact that the vast majority of us are passing our genes on, and thus halting natural selection. For the first time, reaching maturity and spreading our genes has become the rule rather than the exception. Has this shift been enough to halt natural selection?

    What about the fact that more people are now living in cities than in rural areas for the first time in the entirety of human evolution. How do you think this would affect the future of human development. Will we become less robust again, or will sexual selection ensure that the most physically fit pass on their genes.

    What about a catasrophic event? Would it speed evolution up and send us in a new direction, or have we reached our peak of adaptability and thus while a good chunk of the population would die off, those remaining would quickly adapt and spread out over the globe again.

    I have also read that scientist believe that humans have been evolving at a much greater speed, perhaps even 100X faster, in the last 10,000 years. If this is true, what have the physical changes been? I know we have evolved culturally to a huge extent, but what has physically changed?

    What about perhaps evolving through artificial manipulation of our genes. People could inadvertently create a new human sub-species based on changes to our genome? Or even something less drastic, like how women can now screen for genetic disabilities prior to birth and decide to abort. Is this having an affect on human evolution?


Comments

  • Registered Users Posts: 25,560 ✭✭✭✭Kess73


    I think the less robust option is the one that is most likely, unless of course there is a huge extiction event be it a natural one or man made.

    I just think that as technology advances it will continue to encourage man to rely on it further and further, as has happened since the first crude hand tools were made, and as a result lifespans etc may increase a bit further, but as a race we will become that bit softer.


  • Registered Users Posts: 8,551 ✭✭✭Rubecula


    Evolution will continue. We may not see results in our lifetime but we will change. Maybe give rise to divergant species?

    It will take time of course but I think we will have highly intelligent offspring, and perhaps some less intelligent ones too. (Looking out of the window I can see some of the less intelligent ones every day ROFL)

    Seriously I also think that if we ever learn to go to other planets, evolutionary changes will occur all the faster. However that is not in the realm of this forum.

    We are evolving and will continue to do so, we still have prehistoric bodies after all.


  • Registered Users Posts: 68,317 ✭✭✭✭seamus


    Possible branching of the species into the successful and not-so-successful, along the current "class" lines, which as far as I can tell have existed for as long as civilisation has.

    This of course could result in an "underclass" scenario where you have a massive population of a less intelligent, less "civilised" species and a much smaller "elite" population which is generally very intelligent and very talented by comparison. That's millions of years out, of course.

    There's also the possibility á la South Park that within 10,000 or 20,000 years, there'll be a general "convergence" of the species as barriers have been removed and people are no longer confined to a single continent.

    The existence of different human "races" is actually a demonstration of evolution in action. Had Europeans, Asians and Africans (for example) remained disparate for a few hundred thousand years (and survived!), they would likely form distinct species as opposed to variants on Homo sapiens.

    I think it makes sense that a freer intermingling of the human races is most likely to lead to reduction in speciation in humans over the long-term.

    It is worth pointing out though that civilisations tend to rise and fall and rise and fall. A single cataclysmic event (such as a major EMP) has the potential to fracture the planet again and leave everyone stranded and surviving in their own small areas for another few thousand years.

    Past experience tells us that the world as we currently know it (largely global-thinking, democratic and co-operative nations) will not continue for more than a few hundred years


  • Moderators, Science, Health & Environment Moderators Posts: 21,656 Mod ✭✭✭✭helimachoptor


    Kess73 wrote: »
    I think the less robust option is the one that is most likely, unless of course there is a huge extiction event be it a natural one or man made.

    I just think that as technology advances it will continue to encourage man to rely on it further and further, as has happened since the first crude hand tools were made, and as a result lifespans etc may increase a bit further, but as a race we will become that bit softer.

    seamus wrote: »
    Possible branching of the species into the successful and not-so-successful, along the current "class" lines, which as far as I can tell have existed for as long as civilisation has.

    This of course could result in an "underclass" scenario where you have a massive population of a less intelligent, less "civilised" species and a much smaller "elite" population which is generally very intelligent and very talented by comparison. That's millions of years out, of course.

    There's also the possibility á la South Park that within 10,000 or 20,000 years, there'll be a general "convergence" of the species as barriers have been removed and people are no longer confined to a single continent.

    The existence of different human "races" is actually a demonstration of evolution in action. Had Europeans, Asians and Africans (for example) remained disparate for a few hundred thousand years (and survived!), they would likely form distinct species as opposed to variants on Homo sapiens.

    I think it makes sense that a freer intermingling of the human races is most likely to lead to reduction in speciation in humans over the long-term.

    It is worth pointing out though that civilisations tend to rise and fall and rise and fall. A single cataclysmic event (such as a major EMP) has the potential to fracture the planet again and leave everyone stranded and surviving in their own small areas for another few thousand years.

    Past experience tells us that the world as we currently know it (largely global-thinking, democratic and co-operative nations) will not continue for more than a few hundred years

    An EMP will not reduce society to cavemen for a few thousand years. A lot of important stuff is shielded these days, you can be sure the US military is shielded anyway :). Yes it will have a negative effect on the global enonomy but i think this could result in a fairer society over all.
    It would take time to get replace all the chips affected but it would happen.

    But i think as we rely more and more on technology we will become physically very weak life forms. Now this is probably 500+ years away so unless a disaster happens this is how i see things panning out. With probably a subculture of working class people maybe to help with the physical labour.

    Honestly i'd love to have a peak into where human kind will be over the next few milleniums. How far we will go into space what state the earth will be in etc.


  • Moderators, Science, Health & Environment Moderators, Society & Culture Moderators Posts: 60,159 Mod ✭✭✭✭Wibbs


    Well for a start we're still evolving. Indeed we've evolved more in the last 10,000 years than we did in the previous 100,000. A large amount of genechange has occurred in that time. A load pertaining to dietary changes and aggression, but also weird ones like genes involved in sperm production changed. Not just hidden changes either. Compare a homo sapiens skull of 60,000 years ago to today and you will see obvious differences. The skulls have gotten smaller and less robust. Teeth have gotten smaller, eyebrow ridges the same. We've become more gracile over time across all populations from Peking to Dublin to Nairobi. Hell there is even evidence that women are becoming more objectively beautiful in the last 200 years. I'll try to dig up a link to that, its quite fascinating.

    We also live longer. Not just since the industrial revolution either. Indeed the latter actually reduced our overall lifespan. Humans 80,000 years ago rarely saw 35. Suddenly out of the blue we started living longer. three score and ten was suddenly an option. Even though the cultures didnt change. Same tools, same hunting practices, same climates etc, so something changed. They're not sure why. One theory is the grandparent factor became more advantageous. Older types(even in the case of women, no longer fertile) but having them around for longer was selected for.

    The idea that world travel will meld us all together in some melting pot doesnt seem to hold up either. While more people do end up reproducing with different/more diverse genetic lines, overall as a percentage of population its actually quite small. EG Europe has been a crossroads for humans for a very very long time. Armies and nomads and merchants marched, populations moved, yet by reading the average Europeans DNA you can place him or her within a 200 mile radius of their address. Population size is another factor. The bigger the population the more likely novel mutations will arise and survive.

    They already do IE among small populations in the Andes women grow double sized veins and arteries in the womb while pregnant. Inuit have twice the amount of capillaries in the face and hands compared to Africans(who have less than Europeans). Pygmies are very different to Maasai or Swedes say. So even today various populations have slight, even quite strong differences. Enough that if they were another species we may well call them (slight) sub species. Though more likely we would call them breeds like in the domestic dog which has a massive range of differences across the same species. Though functional speciation has already occurred in the dog. A great dane cant naturally reproduce with a pikinese, though are clearly the same species. That may occur in humans too along the lines seamus mentioned. You may get a class/culture speciation barrier over time. The only thing agin that would be female mobility. Women can move up through that system much more easily than males, so unless major cultural change occurs that's likely to continue. New "low" genes would be still flowing up. Then again female beauty is usually the vector for that, so you could reduce the genes for that in one population. Ditto for ambition. It's a scary thought, though as cultures are so fragile, it's unlikely such a speciation event would have enough time to happen.

    These novel mutations may become more marked and new more obvious subspecies may follow. I say subspecies as they're going to be fully reproductively fertile with other humans. After all Neanderthals were up to 500,000 yrs divergent from "us", quite different in many ways, yet we carry their genes because of jiggery pokery in the bushes 60 odd 1000 years ago(I also believe that modern Asian populations also interbred with "their" version of neanderthals).

    I would consider modern humans who moved into Europe and evolved local adaptations(and mixed with earlier hominids) as subspecies of modern humans in North East Africa, who would in turn be different to the southern African population and the Asian population at the time. BTW none of this is based on things like skin colour or any of that guff. IE Australian Aborigines are about the darkest folks on earth, yet are closer to pasty faced Europeans than they are to Africans. We're still all human.

    I suppose what is different is more and more people across the world are getting their DNA sequenced. IMHO we haven't even scratched the surface of that yet. I suspect we'll find novel genes floating out there that defy obvious answers. Plus with the database getting bigger and bigger(imagine in 50 yrs time :eek:) maybe we'll see these local drifts before they get the chance to spread.

    Rejoice in the awareness of feeling stupid, for that’s how you end up learning new things. If you’re not aware you’re stupid, you probably are.



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  • Moderators, Science, Health & Environment Moderators Posts: 10,079 Mod ✭✭✭✭marco_polo


    Interesting post Wibbs, it reminded me of this facinating story from a few years back about the emergence of lactose tolerance in Africa (which took a while to dig out of google :)) . A nice example of both convergent evolution in humans and also culturally driven evolutionary forces at work, the result being genetic changes driven by the wholey cultural phenomon of herding cattle for dairy.
    http://www.nytimes.com/2006/12/10/science/10cnd-evolve.html

    A surprisingly recent instance of human evolution has been detected among the peoples of East Africa. It is the ability to digest milk in adulthood, conferred by genetic changes that occurred as recently as 3,000 years ago, a team of geneticists has found.

    ......

    Geneticists wondered if the lactose tolerance mutation in Europeans, first identified in 2002, had arisen among pastoral peoples elsewhere. But it seemed to be largely absent from Africa, even though pastoral peoples there generally have some degree of tolerance.

    A research team led by Sarah Tishkoff of the University of Maryland has now resolved much of the puzzle. After testing for lactose tolerance and genetic makeup among 43 ethnic groups of East Africa, she and her colleagues have found three new mutations, all independent of each other and of the European mutation, which keep the lactase gene permanently switched on.

    The principal mutation, found among Nilo-Saharan-speaking ethnic groups of Kenya and Tanzania, arose 2,700 to 6,800 years ago, according to genetic estimates, Dr. Tishkoff’s group is to report in the journal Nature Genetics on Monday. This fits well with archaeological evidence suggesting that pastoral peoples from the north reached northern Kenya about 4,500 years ago and southern Kenya and Tanzania 3,300 years ago.

    Two other mutations were found, among the Beja people of northeastern Sudan and tribes of the same language family, Afro-Asiatic, in northern Kenya.


  • Moderators, Science, Health & Environment Moderators, Society & Culture Moderators Posts: 60,159 Mod ✭✭✭✭Wibbs


    Yea it can happen really quite quickly too. Ireland has one of the highest percentage of Coeliac disease in the western world. Gluten intolerance. In the UK they don't have a particularly high incidence of it and genetically we're very close. One theory is our reliance for a few 100 years on the potato for carbs instead of wheat and barley etc and the requirement for gluten tolerance started to fade. Of course that's a problem with some in the health nut industry who may recommend things like soya products to Europeans or Africans. Asian populations have used soya for over 2000 years, we haven't(and those populations dont use as much). So it may actually cause more problems than it solves.

    The ability to metabolise alcohol is another relatively recent adaptation. It's present in Africans and the highest in Europeans, falling off in Asian populations and pretty much non existent in populations like native Australians and native Americans(hence one reason for the problems with it in those cultures).

    One theory goes that Europeans have a high tolerance because they brewed beer and wine to sterilse water, where the Asian populations boiled water and made tea. Alcohol was used less. In the middle ages and before, everyone in Europe drank beer instead of water on a daily basis. You'd have beer for breakfast, lunch and dinner. Kids, grannies, monks the lot. It was low in alcohol(2% usually). If you were rich you'd be knocking back the vino too. When I read about this I reckoned it explained a fair bit about the middle ages for me. Imagine a population of slightly drunk people. Overly amorous. Check. It was the start of the whole romantic vibe in literature and song and all that stuff. Aggressive and quick to anger? Check. The crusades. "Eh Saracen, whatareyoulookingatI'llhaveyouyoubastid". If you're slightly pissed the middle ages makes a lot more sense :D

    Rejoice in the awareness of feeling stupid, for that’s how you end up learning new things. If you’re not aware you’re stupid, you probably are.



  • Registered Users Posts: 2,892 ✭✭✭ChocolateSauce


    As a whole, human evolution by natural selection is a thing of the past, barring some global catastrophe which only a tiny number of people with a certain mutation survive.

    The future of our evolution will be in our own hands. On an evolutionary timescale, it is not very long at all until we beat all forms of genetic disease, so we'll soon be super-human in that sense. Beyond that lies only intense speculation....


  • Registered Users Posts: 1,015 ✭✭✭rccaulfield


    Wibbs wrote: »
    Well for a start we're still evolving. Indeed we've evolved more in the last 10,000 years - genes involved in sperm production changed. Compare a homo sapiens skull of 60,000 years ago to today and you will see obvious differences. The skulls have gotten smaller and less robust. Teeth have gotten smaller.

    Any evidence links for any of these claims? 60,000 years ago is then but it doesn't mean we're evolving now?
    Wibbs wrote: »

    We also live longer. Not just since the industrial revolution either. Indeed the latter actually reduced our overall lifespan. Humans 80,000 years ago rarely saw 35. Suddenly out of the blue we started living longer.
    Doesn't our "out of the blue" older lifespan coincide with our living conditions and especially modern medicine practice more recently?
    Wibbs wrote: »

    After all Neanderthals were up to 500,000 yrs divergent from "us", quite different in many ways, yet we carry their genes because of jiggery pokery in the bushes 60 odd 1000 years ago(I also believe that modern Asian populations also interbred with "their" version of neanderthals).

    .

    Any evidence links to this?- this is not the accepted view anymore from what i've read, we have no vestigal Neandartal dna in our genome.

    Op- we need a geographical separation over a huge length of time to change physically and form different species-the idea of class separation is interesting, i hadn't thought of that but well i just can't see it happening! Modern medicine now allows poorly functioning genes to be passed on-even genes that mean the next generation cannot reproduce can be passed on, thats worth thinking about. We haven't changed a bit physically in thousands of years, if a man from pre egyptian era was born 20 years ago as a baby he could be typing away on this thread right now so whats changed?-Memes!
    Skills, memories, accumulated knowledge all passed on externally of the genome!- Lastly the planet is like a country now in many ways and the southpark scenario seems the likeliest!


  • Moderators, Science, Health & Environment Moderators, Society & Culture Moderators Posts: 60,159 Mod ✭✭✭✭Wibbs


    The future of our evolution will be in our own hands. On an evolutionary timescale, it is not very long at all until we beat all forms of genetic disease, so we'll soon be super-human in that sense. Beyond that lies only intense speculation....
    Possibly, but for example will that be a worldwide thing? Or just available to elites? You could get a sub speciation event in that case. Where rich nations "evolve" "better" humans and poor nations continue on as before. Look at the world wide web. Nice name but its only world wide in certain areas of the world and society. More people are not plugged into it than are. Contraception another example. Then we could look at the science. We may beat genetic disease, but not so long ago we thought we had beaten bacteria. Life has a way of routing around things. Plus we have to be careful about what genes we think are bad or good and removing or inserting them. If you got rid of the gene for sickle cell anemia as an example, yes it would stop a lot of suffering, but at the same time would reduce malaria resistance in the healthy population. These things can have a knock on effect. So care is needed.
    Any evidence links for any of these claims? 60,000 years ago is then but it doesn't mean we're evolving now?
    http://www.news.wisc.edu/14548 gene change has sped up since then. It's gotten faster not slowed down. I quote from the linked article; "positive selection just in the past 5,000 years alone — around the period of the Stone Age — has occurred at a rate roughly 100 times higher than any other period of human evolution." One reason being an exploding population. More animals, more mutations, more chance of mutations spreading. Another reason, exposure to novel environments. Climate(skin colour change an obvious response), foods(lactose and gluten tolerance), population growth(changes in sperm production due to higher competition).
    Doesn't our "out of the blue" older lifespan coincide with our living conditions and especially modern medicine practice more recently?
    No. Around 80,000 years ago we started to live longer and as I pointed out above there were no obvious changes in culture or technology. Modern medicine has small enough impact on individual longevity contrary to popular belief. It does have an impact on childhood mortality. The highness of which drags down overall longevity in tribal types. Engineers have probably saved more lives than doctors by building clean water systems. In any case a man born in say 100BC who made it to 20 had only a slightly lesser chance of seeing 70 as a man born in the 20th century. Indeed with the explosion of lifestyle diseases in the west(diabetes being a biggy) people may actually start to die younger. 2000 years ago Jesus(or an unnamed author) said the average span of a life was three score and ten and the lucky and strong ones could see 80. And this was aimed at a dirt poor peasant audience, yet wasn't considered weird.
    Any evidence links to this?- this is not the accepted view anymore from what i've read, we have no vestigal Neandartal dna in our genome.

    http://news.nationalgeographic.com/news/2010/05/100506-science-neanderthals-humans-mated-interbred-dna-gene/

    Nope you got it backwards. It used to be the accepted view(one I never shared) that we didn't but we do. And considering how little Neanderthal DNA we have to go on, I suspect we may well find a higher amount. I also strongly suspect if we ever sequence Erectus DNA we'll find some of that too, especially in Asian populations.
    Op- we need a geographical separation over a huge length of time to change physically and form different species-the idea of class separation is interesting, i hadn't thought of that but well i just can't see it happening!
    Oh I agree, if we're talking of a speciation event, but novel genes popping up and spreading in a local population could and does and will continue to happen. Adaptations to local foods an example.
    Modern medicine now allows poorly functioning genes to be passed on-even genes that mean the next generation cannot reproduce can be passed on, thats worth thinking about.
    That's true, but that's also evolution in action. It's a blind process, so "bad" or "good" genes are a human value in many ways.
    We haven't changed a bit physically in thousands of years, if a man from pre egyptian era was born 20 years ago as a baby he could be typing away on this thread right now
    Wrong. We have changed physically. That pre egyptian(if he wasn't a farmer) would most likely be lactose and gluten intolerant, so he couldnt have tea and toast while typing away. He would also be genetically unprepared for many pathogens. If he had contracted measles as a child, chances are high he would have died. Remember what happened in the Americas? European diseases killed millions. Far more died from sniffles, than musket shot. We have changed and we're continuing to change and by dint of the large population such changes will be more likely.
    so whats changed?-Memes!
    Skills, memories, accumulated knowledge all passed on externally of the genome!-
    Eh they existed before. Indeed memes external to the genome are part of what make us uniquely human(though other creatures have less complex ones). How do you think they built pyramids and the like? External memes.
    Lastly the planet is like a country now in many ways and the southpark scenario seems the likeliest!
    Again not really. Like I pointed out while air travel has made the world smaller and people are exchanging genes, the percentage that do is quite small compared to the overall populations size. That may change, but even if it did, there are huge areas of the planet and it's human inhabitants that are still isolated. Even moreso genetically. Even today, a Tibetan is most likely going to have kids with another Tibetan, a Congolese with a Gongolese, a Spaniard with another Spaniard, Irish with Irish etc(and the latter two examples are hardly isolated as populations). Even in the land of South Park the US, where by virtue of it being a nation of immigrants, gene flow is higher, for the most part individuals still tend to reproduce with other individuals from their culture and genetic background. I'd still reckon the time where all humans are kinda brown with brown eyes, a populations of Tiger Woods, is a long way away.

    Rejoice in the awareness of feeling stupid, for that’s how you end up learning new things. If you’re not aware you’re stupid, you probably are.



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  • Moderators, Category Moderators, Science, Health & Environment Moderators, Society & Culture Moderators Posts: 47,250 CMod ✭✭✭✭Black Swan


    Continued and increased rapidity of hybridization of homo sapien sapien as the result of enhanced interbreeding between varieties of the species due to the improvement of physical communication and the continued reduction of geographic isolation; e.g., current demographic distinctions between Asian, Black, White, etc., become increasingly mixed and less pronounced over thousands of years, to where such former demographic distinctions are no longer meaningful.


  • Moderators, Science, Health & Environment Moderators, Society & Culture Moderators Posts: 60,159 Mod ✭✭✭✭Wibbs


    Eh no. Not for a long while yet. If ever. Like I've pointed out the amount of mixing as a percentage of overall population is still very low. It may even be lower than in some places in the past(when women were bartered as part of the culture as an example). Just because you can hop on a plane to Mauritius, doesn't mean you're going to get busy with a local and reproduce. Practical example that has been running for many 1000's of years already? Genetic studies across Europe show slight differences by locale and the majority of people in any locale are going to be genetically mapped to that geographical location. While there is evidence of gene flow(where the roman empire went a couple of genes followed) overall we're all still pretty "local". And this is in Europe which has been a crossroads for millennia, with armies and migratory populations ebbing and flowing. Culture certainly hybridised, but DNA not nearly so much. EG The Irish self identify as Celts and we certainly took on much Celtic culture, but genetically we aint middle European Celts. The Middle east an even bigger crossroads for millions of years shows similar localised patterns.

    Even bigger example. Sub Saharan Africa has many local genetically distinct populations and the highest genetic variance on earth. Now modern humans(at least the main bulk of DNA that makes up us all) have been there for the guts of 200,000 years, longer than anywhere else. There are some geographical barriers but we humans are a persistent lot if we think there are resources beyond them. After all humans as a species have had wanderlust for at least 2 million years. Yet after all that time and with all that opportunity, they still have the highest local variances? If this we'll all fall into the melting pot in time notion popular at the mo was likely it would be most likely there, yet we just don't see it. A San Bushman is a very different line to a Maasai, or more Local Zulu, or Baka pgymy and all to each other. An Irish person is as different to a Maasai as a Maasai is to a Zulu. Even the obvious colour of the skin comes into it. San Bushmen are paler, more tawny than the Zulu populations around them. They have epicanthic folds in the eyelids like Asians, are much shorter, leaner and the women also show steatopygia. Yet these two populations have been living beside each other for at least 60,000 years. You do get outliers in any population especially on the edges of contact, but that's what they are, outliers.

    Family sizes may also be a factor and vary quite a bit over different populations. Third and second world cultures tend to have many more children per couple than first world countries. So more say Africans and Indians are born and less Swedes. So in time the world may look more "Indian" say but not because of interbreeding.

    Rejoice in the awareness of feeling stupid, for that’s how you end up learning new things. If you’re not aware you’re stupid, you probably are.



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