Zeb Haradon wrote,
>I can think of one disadvantage to longevity. Generally (and this was even
>more true in the past), an individuals' offspring care for him when he's
>unable to care for himself. This minor drain on your children's resources
>could be enough of a disadvantage to mildly impact their reproductive
>rates - hence your "long term" reproductive rate (by which I mean total
>number of descendants).
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. --J. R.