[ExI] Are Limited Lifespans An Evolutionary Adaptation?

John Clark johnkclark at gmail.com
Sat Jun 20 16:25:11 UTC 2015

On Tue, Jun 16, 2015  BillK <pharos at gmail.com> wrote:

> Assuming a species had a very long lifespan, then what might the results
> be?

A mutation would happen to a gene in one individual that caused it to
devote more of its bodies finite resources to reproduction and away from
long term maintenance; the result would be a individual that had a shorter
lifetime but had more children, and so the mutated gene for this would soon
spread through the population. However if the lifetime was too short the
individual would die before it could care for its young children and so
would have no grandchildren. Evolution must find a good compromise between
maintenance and reproduction that passes the most genes into the next

  John K Clark

Are Limited Lifespans An Evolutionary Adaptation?
> George Dvorsky   6/12/15
> <
> http://io9.com/are-limited-lifespans-an-evolutionary-adaptation-1710634703
> >
> Quotes:
> By running variations of their model hundreds of thousands of times, a
> research team led by Yaneer Bar-Yam from the New England Complex
> Systems Institute (NECSI), in collaboration with the Harvard Wyss
> Institute for Biologically Inspired Engineering, observed that
> evolution favors shorter lifespans in environments where resources are
> scarce and when pressures to procreate are particularly intense. The
> simulations appeared to show that lifespans of animals — humans
> included — are genetically conditioned, and not the result of gradual
> wear-and-tear. It’s a surprising result, one that gives added credence
> to the burgeoning paradigm known as “programmed aging.”
> Without genetically programmed aging, he argues, animals wouldn’t be
> able to leave sufficient resources for their offspring. And this holds
> true for all animals, whether they be rabbits, dolphins, or humans.
> Fascinatingly, group selection — the idea that natural selection acts
> at the group level — was never a consideration in the model. Yet the
> simulations consistently showed that a built-in life expectancy
> emerged among the simulated organisms to preserve the integrity of
> their species over time. This is surprising because a pro-group result
> was produced via an individualized selectional process.
> “Beyond a certain point of living longer, you over-exploit local
> resources and leave reduced resources for your offspring that inhabit
> the same area,” Bar-Yam said. “And because of that, it turns out that
> it’s better to have a specific lifespan than a lifespan of arbitrary
> length. So, when it comes to the evolution of lifespans, the longest
> possible lifespans are not selected for.”
> ------------
> This new theory is still controversial and the article continues to
> discuss the alternatives.
> Aubrey de Grey also comments.
> But I like it. Resource driven ageing via evolution just seems 'right'.
> BillK
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