Is age part of evolution?

Discussion in 'Biology & Genetics' started by darksidZz, Mar 15, 2012.

  1. darksidZz Valued Senior Member

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    I'm thinking is there evidence that aging is actually part of the evolutionary process, and that it exists only due to this reason. Perhaps we can merely shut it off? What might happen to humanity if we all didn't age after 20 or 30?
     
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  3. Pincho Paxton Banned Banned

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    I think its the bonding that breaks down gradually due to entropy. Blow a balloon up, and leave it alone, it goes wrinkly. Blow it up again like feeding it, and wait, it goes wrinkly. After many repeats, the balloon loses its bonding, and breaks.
     
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  5. billvon Valued Senior Member

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    I think it's the opposite. Evolution drives us to remain healthy and active through our childbearing years - and then it's done with us. Systems break down and are not repaired because there is no (evolutionary) drive to make them more reliable.

    Want to extend humanity's lifespan? The one guaranteed and effective way to do that is have everyone wait to age 45-50 before they try to have kids. That will introduce a strong evolutionary pressure for longevity.
     
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  7. origin Heading towards oblivion Valued Senior Member

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    No pincho that is an explanation of stretch marks.

    There is no one thing that causes aging. It is a multitude of things. Evolution has programed our bodies to be able to reproduce and survive long enough to protect our young until they can fend for themselves. Evolution (forgive my personifying it) doesn't give a rats as about us surviving past that point. From an evolutionary point of view a 150 year old person yields no benefit to the survival of the species.

    If we didn't age then we would have wall to was people and it would be a living hell.
     
  8. spidergoat Liddle' Dick Tater Valued Senior Member

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    There is some evidence that the existence of old people is a product of evolution. Grandmothers in particular perform an important child care function.
     
  9. scheherazade Northern Horse Whisperer Valued Senior Member

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    The human life expectancy has been measurably increasing with the advance of technology and medicine and so has our capacity for reproduction into later years also advanced.

    In that regard, we have been influencing the evolution of our species, though I realize that some may interpret 'evolution' differently.

    To everything, there is a season, and without aging and death we would very soon expand beyond the ability of the planet to support. I'm rather in agreement with the summary offered by origin.
     
  10. scheherazade Northern Horse Whisperer Valued Senior Member

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    I likewise agree that our aging population serves as a repository of life experience which is beneficial to the following generations.

    So, too, is there benefit from having members of society who do not merely serve the process of reproduction. There are many supportive roles, many of them quite dangerous, which are best filled by those without immediate dependents.
     
  11. Aqueous Id flat Earth skeptic Valued Senior Member

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    :roflmao:

    Someone else was thinking the same thing:
    http://en.wikipedia.org/wiki/Evolution_of_ageing
    Somebody else was thinking the same thing here too:
    http://www.nature.com/nature/journal/v460/n7253/full/nature08221.html
     
  12. Jeeves Valued Senior Member

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    I don't think the products of a heterogeneous technological society provide any useful information about the evolution of social animals. You'd have to study an intact organic colony in its natural habitat, in order to see what role aged members play in its viability. I'm sure that's been done successfully with many other species, but with human colonies, problems arise: hardly any colonies remain undisturbed for the generations it takes to collect and compare such data.
     
  13. billvon Valued Senior Member

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    So do child care centers and the WIC program - but neither was selected for via evolution.
     
  14. Aqueous Id flat Earth skeptic Valued Senior Member

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    Yes, absolutely.

    Then there's this approach:

     
  15. skaught The field its covered in blood Valued Senior Member

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  16. scheherazade Northern Horse Whisperer Valued Senior Member

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    Unless you consider societies as collective entities capable of evolving.
     
  17. Hercules Rockefeller Beatings will continue until morale improves. Moderator

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    It’s part of the evolutionary process in the sense that aging is a physiological trait that has evolved in complexity in organisms through time. The aging process is intimately linked to metabolism and the immune system. This is why caloric restriction remains the most successful lifespan-increasing strategy for mammals (albeit not an attractive one).

    In simple model organisms used in research, such as nematode worms (C.elegans) and fruit flies (Drosophila), there are a relatively small number of key genes that regulate aging. Thus, in these organisms, the genetic alteration of a single gene can have dramatic effects on lifespan and aging. For instance, mutations in the C.elegans daf genes increase lifespan by ~2-fold (ie. from 2-3 weeks to ~5 weeks). Daf genes are part of an insulin-like signalling pathway.

    When you move up to a more complex model organism such as the mouse you find a greater number of genes linked to aging in accordance with the more complex metabolic and immune systems of the mouse compared to flies/worms. Each of these genes on their own plays a much less significant role in aging. For instance, mice carrying the same mutations in the same genes as the C.elegans mutants display only an ~10-15% increase in lifespan at most (I think, from memory).

    When you get to humans there are a very large number genetic polymorphisms associated with longevity, none of which on their own confer any measurable increase in lifespan. It’s not uncommon to find people on interweb forums who think that increasing human lifespan is merely a matter of tinkering with single genes as we do in flies and worms. Not so, not by a long shot.


    We cannot do that and nothing I’ve ever read leads me to believe we will ever be able to do that. So that’s a purely hypothetical question that can be discussed in a sci-fi sort of way.
     
  18. GeoffP Caput gerat lupinum Valued Senior Member

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    Loss of telomeric ends. Probable gene expression loss, when you think about it. Duplicate often and duplicate early.
     
  19. iceaura Valued Senior Member

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    There is a large body of research and modeling on the role of lifespan in evolution and vice versa. Some fairly clear relationships between body size, metabolic rate, age at reproduction, and age at death, have been laid out.

    Humans are outliers. For a mammal, we live about twice as many heartbeats as would be expected for our size body and age at reproduction. But all mammals have what appears to be an inherent lifespan, and many advantages accrue from the point of view of the genes involved - for one, prevention of an accumulation of non-reproductives competing for resources with the fertile.
     
  20. billvon Valued Senior Member

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    We definitely are.

    However, when people talk about the "evolution of society" they're generally talking about something different than Darwinian evolution. From a purely Darwinian aspects, societies that require women to have as many children as possible, ban birth control and abortions, discourage women from working, euthanize the old and diseased etc are more apt to create a lot of offspring and do better than other societies. Yet we would call some of those practices repressive and backwards, and often refer to the "evolution of society" as the gradual increase in rights for everyone. Those two aren't really the same thing.
     
  21. river-wind Valued Senior Member

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  22. iceaura Valued Senior Member

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    Not necessarily.

    If it's the society that is competing with other societies via Darwinian evolution, prosperity and technological superiority might easily overwhelm its foes' larger but sickly and uneducated populations.

    And in Lamarckian terms, a possible pattern of evolution for social structures and cultural features, a society that simply breeds in place risks much, compared with a society that spreads itself around, takes over other people's cultures, reproduces as a society in far-flung environments.
     
  23. Saturnine Pariah Hell is other people Valued Senior Member

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    Interesting hypothesis, however the aging process would be more suited for “natures" way of maintaining balance in the biosphere, take for example the Octopus and Salmon. After the male and female mate and lay their eggs both begin to age at an alarming rate until death, oddly dying right before their offspring hatch. So those could be examples of specie's evolution pressuring for the parents to die off leaving less completion for their offspring to deal with. This would also maintain a sustainable usage of resources in said ecosystems. All energy that is taken must be given back into the system at one point or ether becoming lunch for another or fertilizing the producers.
     

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