A field called life history theory deals with this sort of question.
In general, considering what is “good for the species” is the wrong way to think about things.
As for Asimov, I would be surprised if he was the first to make this observation. Popularizers are often credited by lay-people with things they are just relaying.
Probably not. We do a lot to maintain the health of our pets and domestic animals, and none of them, even the ones that are larger than we are, ever live anywhere near as long as we do.
This is purely speculative, but it could be related to the fact that we are evolutionarily somewhat juvenilized compared to our nearest relatives. As least in some aspects, such as cranial structure, we are closer to juvenile apes than we are to adult ones. Our very long developmental period and delayed maturity also could have something to do with prolonging the rest of our lives.
I would not be in the least surprised that Asimov picked it up from some previous source. I would, however, be totally flabbergasted if that source turned out to be an article published by Susanann. 
I’ve read that the other primates, like chimpanzees and gorillas, have a total number of heartbeats that’s about halfway between the standard billion and the higher human total.
The idea that lifespan is inversely proportional to metabolism rate dates back to 1900 or so and to a scientist named Max Rubner, long before either Asimov or Susanann (http://books.google.com/books?id=EI8...Rubner&f=false).
An explicit calculation of a billion heartbeats being typical for a mammal is mentioned here Scientific American - Google Books - in an article from 1941 (in a magazine that Asimov probably read)
Thanks very much. That certainly establishes definitively that Susanann’s claim is untrue (not that I had much doubt in the first place).
Rather than trying to remember the story, I’ll C&P:
God created the donkey and said to him, “You will work unceasingly from sunrise to sunset carrying burdens on your back. You will eat grass, you will have no intelligence and you will live 50 years. You will be a donkey. ”
The donkey answered: ” I will be a donkey, but to live 50 years is too much. Give me only 20 years.” God granted his wish.
Then, God created the dog and tell him, “You will be a dog. “You will guard the house of man. You will be his best friend. You will eat the scraps that he gives you and you will live 25 years. You will be a dog. ”
The dog answered, “Sir, to live 25 years is too much, please give me only 10 years.” God granted his wish.
Later on, God created the monkey and said to him, “You will be a monkey. You will swing from branch tobranch doing tricks. You will be amusing and you will live 20 years. You will be a monkey.”
The monkey answered, ” Sir, to live 20 years is too much, please give me only 10 years.” God granted his wish.
Finally, God created the man and said to him, “You will be a man, the only rational creature on the face of the earth. You will use your intelligence to become master over all animals. You will dominate the world and you will live 20 years.”
Man responded, unsatisfied, “Sir, I will be a man but to live only 20 years is very little, give the 30 years that the donkey refused, the 15 years that the dog did not want, and the 10 years the monkey refused.” God granted his wish.
And since then, man lives 20 years as a man, he marries and then spend the next 30 years like a donkey, working and carrying all the burdens on his back. Afterward, when his children are gone, he lives 15 years like a dog, taking care of the house and eating whatever is given to him, so that when he is old, he can retire and live 10 years like a monkey, going from house to house, from one son or daughter to another, doing tricks to amuse his grandchildren.
You stole this from me.
This is my theory, first published in a scientific publication in 1032.
As part of my “higher education,” I looked into this a long time ago, and one thing I found particularly interesting was a concept called the rectagularization of the survival curve. A survival curve plots the percentage of a cohort, all born at the same time, that are alive at a given age, with percent alive on the Y axis and age on the X axis. So, at time 0, the Y intercept, 100% of the cohort is alive. As time goes on, and people (or what ever organism is being graphed) die, the slope trends downward. It reaches the X intercept when everyone in the cohort has died, at the age of that person, the one who lived the longest. As I recall, throughout most of human history, the curve has dropped sharply at the start, reflecting a high infant mortality rate, then relatively leveled off, then started to drop more steeply in middle age. So the over all shape was roughly saddle shape. As infant mortality lessened, and people lived longer, the curve became more rectangular, with a higher percentage of people living into older age. But now the sharp drop is at the other end, at the older ages.
When this analysis was empirically applied to nonhuman organisms, and as I recall it was applied to things ranging from bacteria and yeast to fruit flies and mice, and the respective living conditions for each organism were optimized, a similar effect was noted. It seemed that there was (is?), even under optimum living conditions, a finite and fairly unmodifiable maximum life span for a given organism.
Incidentally, and, again, if I recall correctly, the one thing that consistently extended the lifespans of (every? can’t recall) organism studied to that maximum point was caloric restriction. And pretty drastic restriction it was. Don’t recall the actual amount, but I remember one guy, who was trying it himself, remarked that he was always hungry. So much so that he said that even if he doesn’t actually end up living a long time, it sure will feel like a long time.
If reptiles and birds don’t fall on the general line of mammals, is there any data on whether they fall onto a different number for birds and another for reptiles or do different species just scatter all over the place and this conformity is unique to mammals?
The relationship is very interesting.
But the linked-to graph is annoyingly designed to mislead. It’s a log/log graph with 2 orders of magnitude on the y-axis for lifespan. Beats/lifetime (on the x-axis) would use the same 2 orders of magnitude if heartrate were constant and, because of the effect, the data fits into about 1 order. Yet, to emphasize the effect, the graph spends 14 orders of magnitude on the x-axis, 13 of which are unused.
Misdesigning graphs to make a point is a big turn-off for me.
The graph also includes a data point for something called a “hampster”, which I take to be a mysterious animal as yet unknown to science. I’m not buying that this graph ever appeared in a respected scientific publication.
Not to mention TWO data points labeled “WHALE.”
I took a class in human development as part of my degree. It’s been quite a while, but we studied senescence as part of the class. Anyway, as I recall, species which are safer live longer than others. For example, bats, which have a relatively low rate of predation, live an awfully long time compared to a lot of similar sized mammals. Turtles are protected by their shells, birds have fewer predators, humans use various methods to be safe, etc. The general correlation between body size and lifespan probably comes from the fact that bigger animals are generally safer than smaller animals. The safety = longer lifespan issue is borne out in groups of species. For example, seabirds have fewer predators than other types of birds and also longer longer on average.
I just did a google search to make sure I was spelling senescence right and wikipedia agrees.
I read an article in the Smithsonian (Solving the Aging Puzzle - January 1998)
The article is about the research of Steven N. Austad, a gerontologist and evolutionary zoologist. The theory that Austad proposed is that our natural life span is dictated by the probability of dying from something besides old age - that is, if there’s a good chance that most of the population will not live longer than n years due to predation, disease, injury, and food supply, then the expected age span should be around the same length of time.
Looking at the outliers, some of the longest lived animals tend to be well-armored, extremely large or in an area with no natural predators. It may be a testament to human intelligence that we are long-lived for our size.
Austad conjectured that if his theory was true, then he should be able to find an isolated population of a particular animal where the population had a different lifespan due to differences in external factors. He found a population of racoons (IIRC) on an island just off the east coast in one of the southern states - the racoons had no natural predators on that island and had a natural lifespan of about 3 years longer than the mainland racoons.
So when folks from the Southeast haven’t seen someone in a coon’s age, they’ve been waiting longer than us inlanders.
I found this thread from a link that Andy L posted in a similar discussion I was posting in.
There are indeed quite a few outliers, but they are still a minority. So it actually is true, in a general sense. Wasn’t it originally the conclusion of Aristotle (if so, then Asimov must have acquired the info from him)?
Actually, old age was pretty rare until around 30,000 years ago (about 170,000 years after modern humans first appeared). And I don’t think you can use the bible as a source for lifespans in the past. Even though it mentioned ages of three score and ten and four score, it also mentioned ages of 930 and over. Ccould seriously believe me if I told you that there was a person who lived 930 years, and that the universe is only 6000 years old?
You missed his point. Blake is a professional biologist IIRC and he wasn’t making any biblically based arguments.
The key point is that life span and life expectancy are two very different concepts that people commonly confuse. What he said is true. Life span refers to the built in biological clock that starts ticking when someone is born and guarantees that they will not live past a certain age (the absolute upper limit known is about 120 years but much lower for the vast majority of individuals). Even modern medicine still can’t do anything about that. It is a version of what people colloquially refer to sometimes when they say a really old person died from ‘old age’. Their biological processes in general simply become too worn out to support life anymore.
Life expectancy can bounce around all over the place based on general nutrition, war, sanitation, epidemics and quality of medical care. This is the statistic that has greatly increased especially in 1st world countries rather recently in history.
However, there have always been some people that managed to avoid fatal diseases, malnutrition or accidents and lived longer than most people do today even thousands of years ago. It was less likely due to environmental factors and general lack of medical knowledge but life span was the same for a person in 10,000 BC as it is today given a lot of luck.
There aren’t enough fossils in the world to determine that, and there is nothing particularly special about 30,000 years ago. If you are trying to hit the beginning of settled, agricultural life, that would be closer to 10,000 years ago.
Nick Lane spends some time on this in his book, “Power, Sex, and Suicide”, which is about mitochondria. (When I bought it, my wife gave me a funny look until I mentioned the mitochondria.) It’s a very interesting book. I don’t remember the details, but he discusses a number of observations and how none of them quite match the data, but yet might still give us some clues.
10,000 BC maybe, but earlier than that, I doubt it.
Sorry, I think I got my dates confused. It is highly unlikely that people lived as long as we do today prior to civilization.