Problem
Consider a scenario in which a population of hedgehogs has been living on an island in isolation from the population on the mainland. The environments are nearly identical, so they inhabit the same ecological niche. The only difference is that the island has no predators, whereas predation is the highest cause of mortality on the mainland. When reared in captivity, descendants of the island hedgehogs live 1-2 years longer than those from mainland.
Make an argument for why lifespan (as a trait) has evolved differently in these two environments.