Eighth Dimension: #84 Senescence

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Senecscence is biological aging.

It is theorised to be a factor in evolution as there is a clear correlation between birth rate and numbers alongside lifespan.

Take Elephants, they have a gestation period of 22 months, the longest of any living mammal, though the births are usually single. They can live upwards of seventy years, the oldest on record being eighty two. Then look at the American Opossum which has the longest life recorded being four years and just under three months, has a litter between five and nine and has a gestation period of TWELVE DAYS (It also has thirteen nipples, never understood having an odd number of nipples, is it in the middle or what?)

Fascinated I read more on the theories of senescence and what this could mean for humans (There is, for example, an immortal jellyfish) as the most important time for a human is when it can breed - from an evolutionary standpoint. Human women are fertile between adolescence and around the mid forties. Beyond that is unecessary lifespan from an evolutionary standpoint - aside from the need to pass on vital information for survival. The male of the species is pretty much fertile from the time he figures out what goes where to the time he's returned to the earth in peace!

So why do men generally have a shorter lifespan than women? Evolutionary view could suggest that if men lived substantially longer than women then men of an older generation would be coupling with a younger generation, with the tribal nature of primitive humans this left nature to decide that genetics are complicated enough without inviting trouble with tangled family trees! In theory, anyway.

The mitochondrial DNA in most humans appears to have a relatively common source. Suggesting at some point there was a level where the female population was relatively sparse and/or passed around a fair bit. Scientists have compared the possibility with the origin of Eve.

As interesting as the theories that real world applications have for the theory of senescence and its application to reproduction I have a further view.

"Huh, that explains Elves and Goblins then I guess"

And it does! Goblins have short, horrible lives with huge litters on a regular basis whilst Elves are beyond such things popping a sprog once a century and living for about four. Drow live less time but have a much faster reproductive rate to account for the fact they're all murdering each other in spiteful and uninventive ways (because lets face it when you find a way that works...)

But what about tricking the system? A long lived species that reproduces prolifically and artificially prolongs its lifetime and also alters its fertility and reproductive rates, what then? Generally a species will develop depending on the available resources they can thrive and exploit, leading to cyclical natures of flora and fauna where a population flourishes to a point of overabundance then food scarcity in the future reduces the population until the food source recovers. It's a natural cycle that with manipulation can be broken quite easily.

But is it necessarily right?