[ExI] Are Limited Lifespans An Evolutionary Adaptation?

Rafal Smigrodzki rafal.smigrodzki at gmail.com
Fri Jun 19 18:42:53 UTC 2015


On Fri, Jun 19, 2015 at 12:58 PM, rex <rex at nosyntax.net> wrote:
>
> >
> >    ### Sounds like complete nonsense. You can produce arbitrary results
> in
> >    complex models by fiddling with your parameters, so this modeling
> effort
> >    is not evidence of anything.
>
> Impossible to tell without actual code. The main paper is paywalled,
> and probably doesn't have code anyway.
>

### Well, they produced results flying in the face of reality, so it's a
good guess they screwed up.

--------------------


>
> >    There are a few known examples of predetermined lifespans (e.g.
> mayflies,
> >    bamboo) but these are not related to aging, and are not applicable to
> >    humans. Humans only infrequently age under natural conditions, the
> vast
> >    majority die long before aging sets in, so any evolved mechanism
> actively
> >    killing old humans as an adaptation would very quickly be removed by
> >    random genetic drift (just like skin pigment disappears in
> cave-dwelling
> >    animals - it's not an active adaptation but rather lack of selective
> >    pressure needed to maintain the genes for pigmentation).
>
> Whoa! What definition of aging are you using? In the serious human
> models I've seen, humans age markedly, and this fact is reflected in
> the human life table. John Graunt's table is the oldest I've
> seen. Some birds, notably seabirds, were long thought not to age
> because they had an apparently constant rate of death, but recent
> careful work shows that they do eventually start to age.


### Sorry for the simplification - of course, humans do age from the moment
of conception but what I meant is that under natural conditions we hardly
ever age enough to be killed by aging. Humans are killed by predation (both
micro- and macro-predation, including intraspecies predation) and by
accidents of the environment, most notably famine.

And yes, eventually every creature would age enough to die from it, given
protection from predators and accidents, simply because it's impossible to
resist the second law forever.

Rafal
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