ANTH 243 Lecture Notes - Lecture 11: Apolipoprotein E, Pleiotropy, Peter Medawar
20 Sep 2016
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Alfred russel says the timing of death is a function of preventing competition for resources with offspring. Natural selection removes old individuals from the population to make way for younger individuals. Life span is determined by the maximum number of somatic cell divisions. Many animals have longer average lifespans in captivity while others have shorter. Programmed death was not true cause it should of showed no difference in environment. Environment is hazardous for most organisms such that many die before they can grow and experience aging. Mutations have beneficial or harmful effects late in life are not under selection. Mutations that have harmful effects later in life are likely to be passed on to the next generation before they are expressed. Mutations accumulate over time and lead to evolution of aging. Selection shadow: selective pressures on individual decrease as individual ages and passes sexual maturity. Antagonistic pleiotropy theory of aging - george williams.
