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Anuraag Reddy

AIESEC India

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Why evolution could never solve aging?

Maybe aging is an essential mechanism to clear out the old and make way for the new like cells within a body?

Maybe every form of life is already close to the upper limit of life expectancy?

Maybe aging is in the nature of carbon based life and metabolism?

Maybe we genetically sacrifice our longevity to survive the stresses of competition.

Emerging Questions:
Is it that our metabolic processes are over-compensated for dominance in their sexual prime which prove detrimental for longevity?

Is it that genes leading to different lifespans are mixed indefinitely in nature that it was never possible to select for it?

Isn't an organism with a longer span of mating at an advantage?

My hypothesis:
In the absence of change in ones environment, or competitive stresses an organism would eventually adapt itself to survive longer.

If every organism is a product of evolution then there must of course be underlying mechanisms within itself to aid such an adaptive process.

Under the influence of adaptive pressure, it would encourage mutation or variations in order create successful variations and also increase the number of life-cycles and so reducing the lifespan.

Under the influence of competitive stress, the dominance would lead to reproductive success and not the span of mating during ones lifespan.

In the absence of change in ones environment leading to adaptive pressure, or competitive stresses from rivals to prove dominance. Species would evolve longer lifespans.

Just a Theory though! But it would predict that

Lifespans of living fossils which have undergone little change in time should be greater than their relatives which have recently evolved.

Life having evolved on geographically isolated places far from intense competitive pressures should have greater lifespans.

Living things higher up in the food-chain or with few natural enemies should have greater lifespans.

Life span in pair bonding species should be higher than tournament species.

Topics: aging evolution
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  • Nov 22 2011: Peter Medawar suggested an explanation for aging in "An Unsolved Problem in Biology" [1952], which, as refined by G.C. Williams in 'Pleiotropy, natural selection, and the evolution of senescence' [1957], seems adequate and convincing as a core explanation.

    First, observe that many genes have more than one apparent effect (a phenomenon called "pleiotropy"), and that some genes may have one effect that promote survival, reproduction, and the successful raising of offspring and another effect that inhibits it. Whether a gene proliferates over evolutionary time is the result of its average net effect in a particular environment. Second, observe that an organism's genes are expressed differently at different times in its life-cycle. Consider, for example, that a caterpillar and the butterfly it develops into have the same genes.

    Now think of a gene like that for Huntingdon's Chorea in humans, which increases fecundity in young people but causes disability and death in middle age. It should be fairly obvious that such a gene can produce an increase in the rate of its proliferation by trading off length of reproduction for rate of reproduction. In conditions where such genes flourish there is an evolutionary pressure in favour of aging.

    We ought to expect multiple instances of such genes to spread through any gene-pool. Once they are established there is a selective pressure that favours genes that adapt the organism to senescence, such as the genes that are supposed to switch women's efforts from bearing children to raising grandchildren after menopause. Indeed, senescence in animals is so ubiquitous that we must suspect that it is a primitive feature, and that major aspects of ontogeny are adapted to producing a mortal organism, that at least some of the processes of senescence consist of processes of development and growth continued past the point at which other processes dictated senility. See Hamilton, W.D. (1966) 'The moulding of senescence by natural selection'.
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      Nov 23 2011: Hey Brett!
      I believe this post has received less credit than it deserves, so I would like to bring more attention to it. I will read further about "Pleiotropy."

      It is possible that organisms must be trading off longevity to be more competitive in their sexual prime, so they could leave more copies of themselves. All traits were selected for having their advantage, but later in the course of evolution when such traits become more common in the population, competition drove such traits to be expressed around the time of mating, even if it was self-mutilating in the long run.

      Like they say it is better to burst like a cracker than burn like a candle. Reproductive impact mattered more.

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