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Author Topic:   Discussing Evolutionary Theories that Explain Aging
nwr
Member
Posts: 5585
From: Geneva, Illinois
Joined: 08-08-2005


Message 16 of 24 (692248)
03-01-2013 11:52 AM
Reply to: Message 15 by CoolBeans
02-28-2013 10:18 PM


Physically implemented memory requires some sort of structural rigidity. Avoiding aging requires a great deal of plasticity. It's hard to combine both. Biological system do use both, but in different components. The aging shows up most where there is rigidity.

Maybe there's a way of having both, but biology has not invented it yet. Evolution works with what's there, rather than with an imagined ideal.

In terms of a society, the older members of a community provide a degree of cultural memory, often in the form of traditions and folklore. That the older member eventually die, allows the culture to evolve to better fit changing conditions.

I'm just describing what I see as what would have affected evolution.


Fundamentalism - the anti-American, anti-Christian branch of American Christianity

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Genomicus
Member (Idle past 14 days)
Posts: 852
Joined: 02-15-2012


Message 17 of 24 (692309)
03-01-2013 7:02 PM
Reply to: Message 13 by NoNukes
02-28-2013 1:09 PM


Allowing old critters to hang around indefinitely and to continue having offspring actually slows down the development of new types. The result would be species with less adaptability. We get all of the benefit we need by having a reasonably long siring/birthing period in a finite lifetime.

I suggest you read the article CoolBeans cited in depth. Biological aging might seem like an evolutionary paradox precisely because "natural selection designs organisms for optimal survival and reproductive success (Darwinian fitness), so why does evolution not prevent aging in the first place?"

Here's a relevant quote:

For centuries, beginning with Aristotle, scientists and philosophers have struggled to resolve this enigma. The Roman poet and philosopher Lucretius, for example, argued in his De Rerum Natura (On the Nature of Things) that aging and death are beneficial because they make room for the next generation (Bailey 1947), a view that persisted among biologists well into the 20th century. The famous 19th century German biologist, August Weissmann, for instance, suggested similar to Lucretius that selection might favor the evolution of a death mechanism that ensures species survival by making space for more youthful, reproductively prolific individuals (Weissmann 1891). But this explanation turns out to be wrong. Since the cost of death to individuals likely exceeds the benefit to the group or species, and because long-lived individuals leave more offspring than short-lived individuals (given equivalent reproductive output), selection would not favor such a death mechanism.

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CoolBeans
Member (Idle past 1687 days)
Posts: 196
From: Honduras
Joined: 02-11-2013


Message 18 of 24 (692327)
03-01-2013 8:44 PM
Reply to: Message 17 by Genomicus
03-01-2013 7:02 PM


So its a problem for natural selection or do you still hold that idea
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Genomicus
Member (Idle past 14 days)
Posts: 852
Joined: 02-15-2012


Message 19 of 24 (692328)
03-01-2013 8:53 PM
Reply to: Message 18 by CoolBeans
03-01-2013 8:44 PM


Hi CoolBeans,

No, it is not a problem for natural selection/evolutionary theory precisely because of antagonistic pleiotropy.


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CoolBeans
Member (Idle past 1687 days)
Posts: 196
From: Honduras
Joined: 02-11-2013


Message 20 of 24 (692332)
03-01-2013 9:11 PM
Reply to: Message 19 by Genomicus
03-01-2013 8:53 PM


Oh, thanks. Wait arent you an ID supporter?
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Dr Adequate
Member
Posts: 16085
Joined: 07-20-2006
Member Rating: 10.0


Message 21 of 24 (692336)
03-01-2013 9:20 PM
Reply to: Message 20 by CoolBeans
03-01-2013 9:11 PM


Oh, thanks. Wait arent you an ID supporter?

That doesn't mean that he has to be wrong about everything.


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Dr Adequate
Member
Posts: 16085
Joined: 07-20-2006
Member Rating: 10.0


Message 22 of 24 (692339)
03-01-2013 9:28 PM
Reply to: Message 12 by Genomicus
02-27-2013 10:22 PM


I think the question that CoolBeans is posing here is why we age biologically. The issue isn't really why we die; it's why we undergo senescence, and how this can be reconciled with natural selection.

Well, I didn't talk about dying of old age, I talked about deterioration of fitness. My point is that if this will only happen after a member of your species will (in the evolutionary environment, in the natural course of things) have died anyway, then the mutation causing this will at the very least be neutral.

Edited by Dr Adequate, : No reason given.

Edited by Dr Adequate, : No reason given.


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Omnivorous
Member (Idle past 1040 days)
Posts: 3808
From: Adirondackia
Joined: 07-21-2005


Message 23 of 24 (692343)
03-01-2013 9:37 PM
Reply to: Message 16 by nwr
03-01-2013 11:52 AM


nwr writes:

In terms of a society, the older members of a community provide a degree of cultural memory, often in the form of traditions and folklore. That the older member eventually die, allows the culture to evolve to better fit changing conditions.

I'm just describing what I see as what would have affected evolution.

Which parallels biological evolution: it's hard to get new green growth with old woody branches in the way.

What would be the impact of humans breeding across many generations? Well, outrage, sure, and great parties--but surely it would also slow the pace of evolutionary change.

It's no coincidence that death and sex are so closely related in our psyches: we needed them both to get here.


"If you can keep your head while those around you are losing theirs, you can collect a lot of heads."

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Genomicus
Member (Idle past 14 days)
Posts: 852
Joined: 02-15-2012


Message 24 of 24 (692447)
03-03-2013 12:34 PM
Reply to: Message 20 by CoolBeans
03-01-2013 9:11 PM


Oh, thanks. Wait arent you an ID supporter?

Yes, I am, but that's not particularly relevant to the biology of aging


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