The Shape of Aging

An interesting piece on the comparison of aging between species: "The 'shape' of aging describes how much mortality, the risk of dying, changes with age. One way of measuring the shape of aging is the 'aging factor' across species. For example, the common swift has an aging factor of 2, meaning mortality doubles during its adult life, compared with modern humans, who have an aging factor that exceeds 2000. ... Some organisms live a short time, others live a long time. This is the pace of ageing. Short-lived species have a fast pace of ageing, and long-lived species have a slow pace of ageing. Pace describes how quickly the clock of life ticks away. For humans it ticks slowly, for small songbirds like the robin it ticks very fast. At the age of 15, only 2 out of 100,000 girls in Sweden die, but one out of every two women aged 110 will die. This large difference in mortality at the beginning and end of adult life means that for humans the shape of ageing is steep, whereas in other species like the common swift it is shallow. And in some species the risk of death can even fall with age, with older individuals having the least risk of dying. This seems to be the case for the desert tortoise, and for alligators or crocodiles. ... Comparing robins with Swedish women, humans have a slow pace of ageing whereas the robin's is fast, so in terms of length of life the humans are doing best. But if we look at the impact ageing has on death rate the robin wins. Its shape of ageing is fairly flat whereas the humans' is steep, indicating that death rates increase markedly with age ... Not all species with short lives live fast and die young. Robins do, but mountain sheep do things differently. They also live pretty fast but die older. From the data I have, it seems that live fast die young is only one option; you can also live fast and die older, or live slower and die young, or live slow and die old. There might be every combination in nature. That's something we need to find out in the future with better data."



It's scary indeed to see that the swift has an ageing factor of 2 and we have one of 2000. As someone who is a little older than he would like I don't think that's the most encouraging thing I've read today.

Posted by: John at February 21st, 2011 4:49 PM

No, John, it is the other way around. We have an aging factor of 2000 because we changed our planet in a way that is extremely favorable to our survival. The swifts have an aging factor of 2 because they did not manage to do that.

Posted by: Jack at April 3rd, 2014 7:34 AM

Post a comment; thoughtful, considered opinions are valued. New comments can be edited for a few minutes following submission. Comments incorporating ad hominem attacks, advertising, and other forms of inappropriate behavior are likely to be deleted.

Note that there is a comment feed for those who like to keep up with conversations.