> My understanding of why we didn't evolve to have better gene repair and longer lives is that the ideal death and mutation rates in terms of species survival is some finite number greater than zero. Near-immortality, eternal youth and perfect genome repair would be great from an individual perspective, but from a species perspective, those things reduce the ability for genetic innovation.
If this is the dominant effect in how organisms deal with aging, it can explain why we observe aging all around us in the world, but it predicts that, if you track a population over time, you will see lifespans creeping steadily upward. I don't believe this is actually observed.
The phenomenon you describe is generally invoked to explain sexual reproduction. But it is not unheard of for a particular ecological niche to be dominated by a clonal organism; it's just that those clonal organisms sometimes (inevitably?) "fail" very suddenly in the face of new competition. So both ends of the tension between individual good / species-level good can be observed in the world, and it seems that in the case of sexual reproduction species-level good mostly dominates.
I'm not aware (disclaimer: I am an uninformed layperson) of similar conflicts between immortal species and aging ones for an ecological niche. The picture I have of the world is that certain niches are filled by immortal organisms, and other, more macroscopic niches are filled by mortal ones. Though typing this out makes me wonder about things like jellyfish.
To sum up, without seeing much evidence of strong selection for increasing lifespans, or increasing reproductive spans (the individual perspective counts!), and with the general bias not to invoke group selection where individual selection will do, the mortgaging-the-future approach to aging seems like a better explanation to me.
If this is the dominant effect in how organisms deal with aging, it can explain why we observe aging all around us in the world, but it predicts that, if you track a population over time, you will see lifespans creeping steadily upward. I don't believe this is actually observed.
The phenomenon you describe is generally invoked to explain sexual reproduction. But it is not unheard of for a particular ecological niche to be dominated by a clonal organism; it's just that those clonal organisms sometimes (inevitably?) "fail" very suddenly in the face of new competition. So both ends of the tension between individual good / species-level good can be observed in the world, and it seems that in the case of sexual reproduction species-level good mostly dominates.
I'm not aware (disclaimer: I am an uninformed layperson) of similar conflicts between immortal species and aging ones for an ecological niche. The picture I have of the world is that certain niches are filled by immortal organisms, and other, more macroscopic niches are filled by mortal ones. Though typing this out makes me wonder about things like jellyfish.
To sum up, without seeing much evidence of strong selection for increasing lifespans, or increasing reproductive spans (the individual perspective counts!), and with the general bias not to invoke group selection where individual selection will do, the mortgaging-the-future approach to aging seems like a better explanation to me.