December 6th 2007. Melvin Bragg hosts a discussion on Genetic Mutation for the BBC Radio series In Our Time.
At one point in the discussion, someone observed that natural selection doesn't select against those individuals who die in middle age after having produced heirs. But what wasn't mentioned was the idea of death as a useful evolutionary mechanism - since excessive longevity might reduce the turnover of generations and thereby reduce the effective rate of evolutionary change.
Meanwhile, aging parents may produce offspring with a larger quantity of genetic mutations.
Evolutionary biologists are usually careful to avoid making overly teleological statements about the "purpose" or "purposes" of nature, but there is certainly an idea that some things are there because of their evolutionary effect. In this sense, there may be an evolutionary "purpose" for ageing and death.