5

votes

Longevity from an evolutionary standpoint

Answered on August 19, 2014
Created November 30, 2011 at 2:57 AM

While thinking along the lines of the human species as a whole, doesn't it make sense that death of a person after say... 30-35 years of age (after raising offspring) would be optimal? That a shorter lifespan would be optimal for our species as a whole?

If that is true, wouldn't the correct human diet dictate we lead a healthy, flourishing life for a shorter period of time?

If this doesn't make sense I could try to clarify, it's just one of those things that popped in my head.

89e238284ccb95b439edcff9e123671e

(10299)

on November 30, 2011
at 08:48 PM

Suggestion: Dawkins classic: 'the selfish gene'. Pinker agrees and cites Dawkins a lot.

56e59609362978a9dcb390fdeb45427f

(576)

on November 30, 2011
at 06:38 PM

Interesting answer, never thought about it that way, I'm definitely going to check out that book. The fact that genes only care about their own propogation... couldn't you argue that somehow the species as a whole benefits from this in itself? In the big picture why would genes only care about their own propogation? I might be asking to big of a question that will eventually lead to something like "what is the meaning life...", but it's something I'm interested to learn more about.

4781cf8ae1bfcb558dfb056af17bea94

(4359)

on November 30, 2011
at 05:38 PM

Oh, also, human evolved so that females undergo menopause, which happens after...30 years of age, so... how did that trait come about from an evolutionary perspective if paleo women did not regularly live into old age?

0bc6cbb653cdc5e82400f6da920f11eb

(19245)

on November 30, 2011
at 01:33 PM

This is an example of why we need better teaching of evolutionary biology.

96440612cf0fcf366bf5ad8f776fca84

(19463)

on November 30, 2011
at 11:51 AM

It means our genes are evolved to replicate so as to propagate themselves. The life of one individual isn't important for the propagation of the species. Longevity is important only to the individual, and only of secondary importance to propagation (i.e. grandparents helping to take care of grandkids). Hence it's somewhat at odds with evolution, but that doesn't mean there's no way to achieve longevity, we just need to keep looking.

0bc6cbb653cdc5e82400f6da920f11eb

(19245)

on November 30, 2011
at 11:37 AM

If everyone in your family dies at aged 30 you are not going to have a very high reproductive success compared to someone from a family who live to 80 years.

D12142c8cafb16d9af10b3362cb8fb62

(1590)

on November 30, 2011
at 11:28 AM

Sounds like Dr. Rosedale. Stick together; leptin, carbs, spike, longevity... mash together with literary dribble and BAM!... new blog post.

D12142c8cafb16d9af10b3362cb8fb62

(1590)

on November 30, 2011
at 11:25 AM

Most animals are fertile until death. Menopause suggests to us that evolution HAS selected for longevity (a point which can also be used against those who say ''but cavemen died at the age of 25 blah blah'').

0bc6cbb653cdc5e82400f6da920f11eb

(19245)

on November 30, 2011
at 10:20 AM

Have you ever heard of grandparents?

0bc6cbb653cdc5e82400f6da920f11eb

(19245)

on November 30, 2011
at 10:19 AM

Ryan, have you ever raised offspring? I'm pretty sure raising children does not stop when they reach the age of 10.

0bc6cbb653cdc5e82400f6da920f11eb

(19245)

on November 30, 2011
at 10:14 AM

Facepalm.......

0bc6cbb653cdc5e82400f6da920f11eb

(19245)

on November 30, 2011
at 10:14 AM

*Facepalm*.....

A9808a71e03d9b9602aae53622c64d70

(123)

on November 30, 2011
at 09:22 AM

BTW, if this stuff fascinates you as much as it does me, I can highly recommend reading "How the mind works" by Steven Pinker.

499f188c87c6980742b9ba98caa6f563

(683)

on November 30, 2011
at 04:16 AM

A quilt-jay neutralization gets a +1 from me!

4781cf8ae1bfcb558dfb056af17bea94

(4359)

on November 30, 2011
at 03:50 AM

What in the world are you even talking about?

4781cf8ae1bfcb558dfb056af17bea94

(4359)

on November 30, 2011
at 03:49 AM

+1. Also, and this is key, men never lose fertility.

4781cf8ae1bfcb558dfb056af17bea94

(4359)

on November 30, 2011
at 03:48 AM

A QUILT upvote is a Jay downvote....

Ed71ab1c75c6a9bd217a599db0a3e117

(25472)

on November 30, 2011
at 03:09 AM

plus one..........

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6 Answers

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6
A9808a71e03d9b9602aae53622c64d70

(123)

on November 30, 2011
at 09:19 AM

Genes aren't selected for the good of the species as a whole. It is irrelevant whether a shorter lifespan would be optimal for the species. A total lack of violent tendencies towards other humans would surely be optimal for the species as a whole, but a gene producing that behaviour would quickly die out as a mutation that took advantage of everyone else's passivity would flourish.

So genes only care about their own propogation. But that doesn't mean that they only care about the organism that carries them around. You care about your children, as they contain copies of your genes. You care about your brothers and sisters, because their genes overlap substantially with yours. And you care about your cousins and more distant relatives, for the same reason. As an evolutionary biologist once said, "I would lay down my life for two brothers or eight cousins" (mentioned in this article http://en.wikipedia.org/wiki/Kin_selection).

As one gets older, one's chances of reproducing may decline (although if you manage to attain greater social status and material wealth, for men at least, that may not always be the case), but the number of descendants that you have an interest in will quite possibly increase. You are still a boon to your genes if you are a grandfather/mother, and genes which allow you to live longer will allow you to nurture those with similar genes to you for longer.

A9808a71e03d9b9602aae53622c64d70

(123)

on November 30, 2011
at 09:22 AM

BTW, if this stuff fascinates you as much as it does me, I can highly recommend reading "How the mind works" by Steven Pinker.

56e59609362978a9dcb390fdeb45427f

(576)

on November 30, 2011
at 06:38 PM

Interesting answer, never thought about it that way, I'm definitely going to check out that book. The fact that genes only care about their own propogation... couldn't you argue that somehow the species as a whole benefits from this in itself? In the big picture why would genes only care about their own propogation? I might be asking to big of a question that will eventually lead to something like "what is the meaning life...", but it's something I'm interested to learn more about.

89e238284ccb95b439edcff9e123671e

(10299)

on November 30, 2011
at 08:48 PM

Suggestion: Dawkins classic: 'the selfish gene'. Pinker agrees and cites Dawkins a lot.

11
21b36b3de8ff31b0d41e7f0f4b5c1e03

(1688)

on November 30, 2011
at 03:03 AM

First of all, women are fertile into their forties, and then they still have to raise their offspring to a point where they can fend for themselves. That would result in a lifespan of about 60 years.

Secondly, older people represent the stored knowledge/values/experiences of a tribe, especially in times before written language, so they are valuable to have around (healing, plant knowledge, cyclical events like floods etc).

And they're useful for babysitting when everyone else is off hunting/gathering.

4781cf8ae1bfcb558dfb056af17bea94

(4359)

on November 30, 2011
at 03:49 AM

+1. Also, and this is key, men never lose fertility.

4781cf8ae1bfcb558dfb056af17bea94

(4359)

on November 30, 2011
at 05:38 PM

Oh, also, human evolved so that females undergo menopause, which happens after...30 years of age, so... how did that trait come about from an evolutionary perspective if paleo women did not regularly live into old age?

3
499f188c87c6980742b9ba98caa6f563

(683)

on November 30, 2011
at 04:22 AM

Yes, tribal elders are a valuable resource. I think the Quilt is saying that our learning abilities may overcome our innate short lives. Dawkins somewhere says something like: evolution in the human case seems to have said, 'you've got a brain, so just do whatever you can to keep going'.

Anyway, Galapagos tortoises live pretty long, and so do giant redwoods.

3
Ed71ab1c75c6a9bd217a599db0a3e117

(25472)

on November 30, 2011
at 03:09 AM

Longevity is a "biologic novelty" and not something evolution seems to have selected for. But it does appear our brain is capable of altering that set of circumstances. We just have not empirically figured out the key points. Some of us will keep that search up

0bc6cbb653cdc5e82400f6da920f11eb

(19245)

on November 30, 2011
at 01:33 PM

This is an example of why we need better teaching of evolutionary biology.

96440612cf0fcf366bf5ad8f776fca84

(19463)

on November 30, 2011
at 11:51 AM

It means our genes are evolved to replicate so as to propagate themselves. The life of one individual isn't important for the propagation of the species. Longevity is important only to the individual, and only of secondary importance to propagation (i.e. grandparents helping to take care of grandkids). Hence it's somewhat at odds with evolution, but that doesn't mean there's no way to achieve longevity, we just need to keep looking.

D12142c8cafb16d9af10b3362cb8fb62

(1590)

on November 30, 2011
at 11:28 AM

Sounds like Dr. Rosedale. Stick together; leptin, carbs, spike, longevity... mash together with literary dribble and BAM!... new blog post.

4781cf8ae1bfcb558dfb056af17bea94

(4359)

on November 30, 2011
at 03:50 AM

What in the world are you even talking about?

1
0ad4ed16f0afccc544f92e51945482f7

on November 30, 2011
at 08:55 AM

I'm assuming this is based on the idea that following reproduction and child-rearing, it would be better for the group if the individual dies, thus freeing up resources for the more reproductive members? Good thinking; this is an idea which has been proposed several times by evolutionary biologists. However it has been refuted by modelling and by more accessible logic. Evolution doesn't work at the level of 'what is good for the species', or even the group (except in certain very particular circumstances). Natural selection operates on individuals, not groups. For the individual to die in the way you are suggesting it would have to be programmed i.e. selected for. There is no strong selective force at the level of the individual to drive the evolution of such an outcome; it is not in the interests of the individual. Unless perhaps the groups were very small and highly related.

But that is background. Probably it would be too difficult a design task, even for evolution, to have a body which functioned optimally on a diet up to a point, and which was killed in fairly short order by the same diet.

1
A2c38be4c54c91a15071f82f14cac0b3

(12682)

on November 30, 2011
at 03:55 AM

Here's a pretty relevent quote from the book Genome: "Our Stone-age ancestors began breeding at about twenty, continued until about thirty-five and looked after their children for about 20 years, so by about fifty-five they could die without damaging their reproductive success. Little wonder that at some time between fifty-five and seventy-five most of us gradually start to go grey, stiff, weak, creaky, and deaf".

The author explains that after we pass average child rearing age, we are at a point where genes that damage us at this stage of life cannot be evolutionarily selected to die out.

I doubt a "correct" human diet, or anything else really, would have the effect of turning on some kind of gene for altruistically dying, if that was what you were asking.

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