Telomerase; Late-Life Selection; Pleiotropy vs. Mutation Accumulation - Addenda
Some Questions About the Antagonistic Plieotropy, Reserve-capacity hypothesis (Weinstein & Ciszek 2002), Model of Aging
I'm in a hurry, but I can't resist pondering aloud some puzzles concerning antagonistic pleiotropy... the idea that post-reproductive survival contributes to species survival. What we're saying is that even for egg-born animals that never know who their mothers and fathers are, their survival odds are boosted by having these older fish hanging round. It seems to me, as Steve said, that these elders would simply compete with the younger fish for food. It might be, as Steve also implied, that these older fish would be attractive prey for predators. But then, there wouldn't seem to be any reason why shark bait would have be members of the same species as the small fry. And selection depends ultimately on the ability to affect the reproductive odds.
There are other (semelparous) fish like salmon that grow old overnight and die as soon as they've spawned.
The article, Study Backs Theory That Accumulating Mutations Of "Quiet" Genes Foster Aging, mentions that the antagonistic pleiotropy model is the most popular one these days, so there must be cogent reasons for its popularity.