(Part 2) Best aging books according to redditors
We found 46 Reddit comments discussing the best aging books. We ranked the 24 resulting products by number of redditors who mentioned them. Here are the products ranked 21-40. You can also go back to the previous section.
This is at least partially the case, as described in Why Life Speeds Up As You Get Older.
Another part of it is the fact that when you're young you experience all kinds of new things all the time. As you grow older and routine sets in, you will long periods of time with relatively little big changes or new experience and those will kind of merge together in your memory.
You don't remember every single time you made breakfast or drove to work, your memory of those actions consists partly of the last time you did such a thing and partly a blend of many other times you did so. The more monotonous your life becomes, the harder it is to distinguish between specific days/weeks/months/etc because of this effect, which makes those periods seem like a shorter time. A "trick" to diminish this effect is to do new things often.
There are more reasons he explains but I don't remember, these two were the main ones though iirc.
The good news is that there are actually multiple, up-to-date textbooks on the biology of aging:
Caleb Finch also wrote a textbook, The Biology of Human Longevity: Inflammation, Nutrition, and Aging in the Evolution of Lifespans, but it was published in 2007 and hasn't been updated since. There's also the 8th Edition of the Handbook of the Biology of Aging, published in 2015.
Need the following textbook pdf ASAP. https://www.amazon.com/Aging-Older-Adulthood-Joan-Erber/dp/0470673419
Will Venmo $4 upon reception of ebook.
there is no evolutionary advantage to being short lived. You're right, It's not impossible in nature, and yet we are not. But that it holds a competitive advantage is not the only possible reason. Infact it is seriously outdated.
You're forgetting, natural selection doesn't work on a species, it works on individuals.
Imagine a non-aging species:
According to you, the species reproduces until they hit the maximum number of individuals the environment can support. When this happens, ageing becomes evolutionarily advantageous, because it allows the younger members of the species to surpass their elders, and the species moves forward.
The problem is, how would ageing become advantageous? one individual would be born with an ageing gene, and would have a few offspring before dying. But these offspring would never be able to compete with their non-aging brethren. The ageing organisms would have a limited time to reproduce, whereas the non ageing organisms would reproduce until they met their end to environmental factors. They would be able to reproduce for longer, and they would therefore have more children. These children would also be less likely to die from the lack of resources than the mortal children, as the mortal children would begin to deteriorate soon after puberty ended.
The ageing variant would have fewer opportunities to pass on it's mutation than the immortal variant, and it would therefore be removed by natural selection.
Now you might say that we started off mortal, and the immortal ones were removed by natural selection, so lets trun through that scenario, just to be sure.
Take a mortal species at it's environmental limit. Hell, let's even say that they are only able to have a child when someone else dies, as you suggested. Now imagine an immortal mutation happens. This individual would have children at the same rate as his peers. But, so long as he wasn't unlucky, he wouldn't die as soon as they would. They would get old, maybe even infertile, and pass away. Eventually this immortal bloke would be done in by some sort of accident, but he would have produced more offspring than his peers, and his offspring would do the same. They would eventually take over the gene pool.
No, the good of the species isn't the reason we age.
The reason we are thought to age is because of the lessening effects of natural selection over time.
Take the immortal (non ageing) species from before. An individual has a good chance of living ten years without being killed by a natural disaster, infection, bullet to the head, etc. After twenty years, they might have had a few close calls but it would still be unlikely for them to be killed.
Let's say the average non ageing organism is killed after living 60 years. By that point, about half of them ran out of luck avoiding danger, while the other half have managed to stay in a safe environment.
80 year olds would be rare indeed, as one must be incredibly careful, incredibly lucky, or both, to live 80 years without coming into contact with anything lethal.
This means that if a mutation occurred that only took effect after you reached 80, or a hundred years of age, only a very few would live long enough to be affected by it. It could be easily passed on and spread throughout the gene pool.
And remember, the vast majority of mutations are harmful.
The species would easily build up a plethora of harmful genes that take effect after 80 years or so. Natural selection would not be able to remove them as fast as they appeared, because the chances of living to be 80, given the dangerous nature of the environment on earth, is slim.
Imagine now, that this species discovers medicine, learns about the importance of hygiene, and generally removes much of the dangers of the natural world. All of a sudden, living to 60 becomes entirely normal, living to be 80 is average, and some few people live past a hundred years of age. All of those late- acting mutations start to become noticeable. The species calls these late life problems "ageing."
If you want to know more, read Why We Age by Steven N. Austad
ISBN-10: 0471296465 | ISBN-13: 978-0471296461