[ExI] Are Limited Lifespans An Evolutionary Adaptation?
pharos at gmail.com
Tue Jun 16 11:13:33 UTC 2015
Are Limited Lifespans An Evolutionary Adaptation?
George Dvorsky 6/12/15
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'.
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