Re: longevity
CurtAdams@aol.com
Sun, 21 Nov 1999 16:16:12 EST
In a message dated 11/20/99 8:06:51 PM Pacific Standard Time, jr@shasta.com
writes:
> Yes, I can see that. I still wonder if evolution can select for shorter life
> spans in a particular population (not necessarily an entire species) via
> speeding up the process of adaptation: shorter generations equals more
genetic
> experiments to run, and hence greater probability of solving problems
presented
> by a changing environment. If so, this would yield an advantage to a
short-lived
> population over a long-lived one.
It can, it's just that any individual advantages will overwhelm the group
advantage.
Roughly, a group allele benefits only with the frequency of groups going
extinct. An individual allele benefits with the frequency of individuals
dying. Obviously the latter is far more common, so the selection to improve
individual fitness is typically orders of magnitude larger than group
fitness.
There's an experimental problem in that the power of group selection is
generally lower than the lowest effects on individual selection we can
detect. So we can't say that individual selection on any particular real
trait or allele is low enough for group selection to go.