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An Attenborough TV show suggested that the reason people live long compared to animals is that grandparents are needed to help raise the young. The grandparents
by skookumchuck 9y ago
An Attenborough TV show suggested that the reason people live long compared to animals is that grandparents are needed to help raise the young. The grandparents raise the young while the parents work/hunt/farm/whatever.
So having healthy grandparents gives a survival advantage.
- fauigerzigerk 9y agoThis theory is mentioned in the article as well, but it doesn't seem very plausible if we're talking about living into the 80s or 90s. At that age, the effect should be reversed as people often need care themselves rather than caring for grandchildren (who may be adults by that time anyway) I suppose the "grandmother theory" originally only explained why women live beyond menopause, not into their 70s, 80s or 90s.
- mannykannot 9y agoIncreasing longevity to the point of incapacity may be a consequence of improved health care, rather than biological adaptation.
- cpeterso 9y agoAnd while average life expectancy has been increasing for a long time (thanks to improved health care), the maximum life span has not. The oldest living people are still "only" about 115-122 years old.
- dmix 9y agoIs this because "improved health care" only makes typical illnesses treatable/prentable whereas maximum lifespan (ie, the deteriation of cells/organs/etc with age) are not being focused on? Or is it because they are very challenging things to extend?
- azernik 9y agoAlzheimer's in particular does not reduce lifespan all that much; rather, it increases the resources that children and grandchildren need to use to care for the parent. So selection against Alzheimer's would presumably (we have very little evidence for any of this) be even stronger than selection against traits that, say, killed at 70.
- saimiam 9y agoIs actually caring for an Alzheimer's stricken relative a new phenomenon? Could it be that a hundred years ago, a chronically ill, continually deteriorating relative was just left in a room to waste away?
- azernik 9y agoProfessional Alzheimer's care is new;, without good professional work you're going to get sores and muscle atrophy and all kinds of other complications that can be fatal at old age. We've gotten very good at dealing with those, but not at actually curing the underlying disease. (Speaking from family experience.) Maybe even more importantly, though, 100 years ago other, unrelated diseases of old age were likely to get you well before Alzheimer's really got bad.
- skookumchuck 9y agoEven today, people rarely die from Alzheimer's, because something else gets them first, as Alzheimer's is a very slowly progressing disease.
- skookumchuck 9y agoPrimitive societies are known to abandon old people to die when they become a burden rather than an asset.
- ch4s3 9y agosome
- skookumchuck 9y agoWhat's a nomadic tribe to do with someone who can no longer keep up? When there is insufficient food (commonplace in older societies) who is going to get the food? When resources get scarce, there are a lot of ugly realities.
- dredmorbius 9y agoYou might do better to provide citations over argument.
- skookumchuck 9y ago"Traditional nomadic tribes often end up abandoning their elderly during their unrelenting travels. The choice for the healthy and young is to do this or carry the old and infirm on their backs — along with children, weapons and necessities — through perilous territory. Also prone to sacrificing their elderly are societies that suffer periodic famines. Citing a dramatic example, Diamond said Paraguay’s Aché Indians assign certain young men the task of killing old people with an ax or spear, or burying them alive." http://newsroom.ucla.edu/stories/jared-diamond-on-aging-150571 http://newsroom.ucla.edu/stories/jared-diamond-on-aging-1505...
- dredmorbius 9y agoThanks, exactly.
- interfixus 9y ago
- bagacrap 9y agoBut many animals reach sexual maturity much faster (e.g. cattle at ~40 months) so you would expect many more generations to be alive simultaneously.