Does Darwin's theory say that we'll evolve even further than we already have?

Discussion in 'Biology & Genetics' started by science man, Nov 8, 2010.

  1. iceaura Valued Senior Member

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    That's not at all clear.

    The assumption is false, for one thing. For another, narrowing the gene pool only makes "evolution go faster" if the result is an evolutionary change or step - but what you have done is preserve the existing norm, which is not allergic to peanuts. You have in that sense prevented, rather than abetted, any nascent evolutionary change.
     
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  3. Skeptical Registered Senior Member

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    Evolution happens more rapidly in response to environmental changes.

    And boy, have we humans been changing our environment!
    I still think the biggest change in human genetics will be deliberate, and natural selection will be a tiny influence. However, leaving out the massive effect of deliberate genetic modification, what will natural selection do?

    Clearly, it will work on the changes in environment. It will not necessarily work to our 'benefit'. There is no rule that say it has to improve our brains, for example, and many people see the propensity for less intelligent people to breed more as an evolutionary trend towards greater stupidity.

    Another example is the effect of fertility control. For the first time ever, women can have only those children they want. One effect of this is that over the next few generations, more and more of the world's population will be descended from those women who want more children. We are breeding the desire to have lots of children into our women.
     
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  5. Hipparchia Registered Senior Member

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    This just seems wrong to me. The world is changing rapidly culturally and this is putting enormous pressures on many people. Mental illness and depression seem much more common. Surely we should expect to see adaptations that make people more tolerant of rapid change and what we currently perceive as stressful situations.

    To my mind the pressure for adaptation is higher than it has been for millenia, possibly higher than it has every been in human history. What do you think?
     
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  7. Kennyc Registered Senior Member

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    I think that is more of a mental adaptation than an environmental one -- very little physical adaptation involved.
     
  8. CptBork Robbing the Shalebridge Cradle Valued Senior Member

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    What I'm saying is the percentage of humans allergic to peanuts would never ever change, if we kept giving medicine and other assistance to those with such allergies so as to level the playing field. They will always have equal chances of surviving and reproducing and those traits would keep getting passed on from generation to generation indefinitely, there would be no evolution towards a species free from peanut allergies.

    And to argue that medicine in any way enhances evolution by keeping the gene pool as broad as possible- perhaps that would be so if the world weren't already overpopulated, but as is the case in several parts of the world and will soon be in many more, there simply ain't enough to go around for everyone, and there will be competition for survival. Medicine favours survival of the wealthiest, not survival of the physically fittest.
     
  9. yes I know, as long as we don't overpopulate the earth that will stay true. Btw, even if we didn't overpopulate the earth we still would have to migrate off the planet because eventually the sun will explode, which is one of the things I want to work on when I get older. (when my occupation isn't student like it is now)
     
  10. Skeptical Registered Senior Member

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    I keep encountering the overpopulation myth. The world currently has about 6.7 billion people, and will grow till it has around 9 billion (plus or minus an error factor), at which stage, population is projected by the world's top experts in the United Nations, to level off or even decline.
    www.un.org/popin

    Feeding 9 billion is well within human abilities, and does not require severe environmental damage (at least, not much more such change compared to what has already been inflicted). Hydroponics can feed an average person with 100 sq.m of land, as long as that person is vegan. This permits more than 9 billion to be fed on a lot less land than is already in agriculture.
     
  11. synthesizer-patel Sweep the leg Johnny! Valued Senior Member

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    Its down to sexual selection.

    Humans are the only mamals whose females have permanently swollen mammary glands - this serves no immediate survial function - in fact is more likely an impediment.

    The hypothesis is that this was selected for through partner selection when our ancestor species began to walk upright - as upright walking females could no longer do what most other primates did to signal sexual availability to males - i.e wave their butts in the air - they, in essence, grew new butts on their chests - selected for in size over many generations as males were more likely to mate with females who's breasts remained swollen for longer periods between lactation and / or were larger.

    The upshot of this (and I love this) is that the primary function a human females breasts are as a sexual attractant for men - providing milk is only the secondary function as having mamary glands in permanently swollen state is not a requirement for this function to be fulfilled.

    So guys - next time you feel bad about gawping at a womans rack, dont! - thats what they are for!
     
  12. Hipparchia Registered Senior Member

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    Mental adaptations are contingent upon neurological structure and chemical balances in the brain, both of which are aspects of the genotype and are therefore subject to selection.
     
  13. Kennyc Registered Senior Member

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    993
    Possibly to some extent, but the physical nature of the brain does not determine its capabilities. It is a different level of adaptation. IMO
     
  14. woowoo Registered Senior Member

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    if its not physical then maybe it chi

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  15. Hercules Rockefeller Beatings will continue until morale improves. Moderator

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    People always start focusing on food when it comes to the (over)population issue. Certainly it’s of major importance, but there are other major infrastructure requirements that need to be addressed.

    Our technology has increased food production efficiency. We can feed more people with less manpower. So, if Earth’s population expands by another 3 billion, the significant majority of those extra people will reside in cities. And a large proportion of the existing 6 billion will migrate to cities in the meantime.

    Water, cars, transport, roads, sewerage, electricity production, schools, health care, hospitals, childcare, sanitation, law and order, housing, communications, recycling, waste disposal, and much more. You won’t find a major city now that claims to be on top of all, or even most or some, of those things, let alone with a few additional million people. And it all has to be done in a sustainable way. It's a big ask and I'm in no way convinced we can do it sustainably for a world population of >9 billion. We can't do it now.
     
  16. Skeptical Registered Senior Member

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    Hercules

    The biggest problems we have with lots of people living in cities is due to poverty. Hopefully, with a stable population of 9 billion, and a century or two of economic growth, we can develop away from that damaging poverty.

    Actually, the biggest environmental problems do not come from city dwellers. Sure, the problems are more concentrated in cities, and we see greater problems per acre. But it is away from cities where the greatest harm is done, though this harm is spread over a much greater acreage. Deforestation. Soil loss. Farm pollution etc.
     
  17. Hercules Rockefeller Beatings will continue until morale improves. Moderator

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    I totally agree that the deforestation that has occurred world-wide is horrendous, and it’s one of this planet’s greatest problems. But it’s a direct result of over-population. Developing countries deforest to provide timber for their own expanding construction and manufacturing needs, the construction and manufacturing needs of the Western world, to provide land for their expanding populations, to plant palm oil plantations to meet the food industry demand of the Western world, and because it’s the only employment for significant numbers of people who would otherwise be destitute.

    It’s all about population. It’s further evidence that we cannot sustain a predicted 9 billion population, IMO.
     
  18. woowoo Registered Senior Member

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    to eliminate poverty we are going to have to make more people prosperous, which
    should be self evident, therefore if we are all going to be consuming more
    resources. and where are these resources coming from: forests, oceans,
    farmlands. which means more destruction of the environment.
    humans are essentially selfish, aggressive, greedy, self interested foraging animals,
    who care little for their habitat with a slash and burn lifestyle.
    The idea that an addition 3 billion of these creatures to the biosphere
    is going to be anything but a disaster for the planet flies in the face of
    all the evidence so far. To imagine that somehow we are all suddenly
    going to become peaceloving, altruistic, fluffy little fairies is fantasy.
    Sooner or later the population is going to come down, in nature this
    is usually accompanied by a catastrophic sudden decline brought
    on by environmental collapse or disease. the is no evidence we are
    going to behave any differently, we will suffer a similar fate. technology
    is not going to save us unless we use it to scale back the population,
    but with a new global order and a one world economy based on consumption
    there will always be a need to overpopulate to sustain growth. We are
    doomed, save your own skin while you can, if you can.

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  19. Kennyc Registered Senior Member

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    Could be if you can provide evidence for its existence. :bugeye:
     
  20. ElectricFetus Sanity going, going, gone Valued Senior Member

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    woowoo,

    Technology has allowed us to get this far in population growth, so I would not suppose it can't get us farther. I'm not saying that civilization collapse is impossible, it quite likely and something to be very concerned about, but our doom is far from guaranteed!
     
  21. Skeptical Registered Senior Member

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    1,449
    To woo

    That was a most hysterical post. There is actually no evidence that increased prosperity must require greater consumption of resources. For example : a lot of wealth can be obtained through such things as recycling. The old British saying : "Where there's muck there's money."

    Oil can be obtained by growing algae in sewage ponds. Wealth can be obtained by substitution. Instead of using resources that are in short supply, or require environmentally degrading methods of exploitation, substitute with materials of lesser impact. eg. Bioplastics.

    Basically, prosperity is a result most of all of ingenuity. Become rich through being smart.
     
  22. woowoo Registered Senior Member

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    its OK, i'm just unwinding, venting gas, i find it liberating.

    you're right about the sewage, there's going to be lots of that,
    would be a good investment on the stock market.

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  23. ElectricFetus Sanity going, going, gone Valued Senior Member

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    Good point, many countries have higher standards of living then grossly wasteful USA, and some do so up to and less then half the energy expenditure per person as the USA.
     

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