Life History And Aging Flashcards
Senescence
Decline with age and reproductive performance physiological function or probability of survival
Rate of living theory
Aging caused by irreparable damage to cells and tissues , no variation for better repair mechanisms?
Predictions for rate of living theory (2)
ageing rate correlated with metabolic rate
Species should not evolve longer lifespan whether subject to natural or artificial selection
Does the rate of living theory make sense and why does it keep persisting
It doesn’t add up but things like telomeres seem to add up except in some animals, p53 (more or less doesn’t stop dying). We have genetic variation for longer lifespans but it didn’t evolve
Two hypotheses of evolutionary theory of ageing
- mutation accumulation hypothesis
- antagonistic pleiotropy hypothesis
Mutation accumulation hypothesis
Reproductive success doesn’t change with living longer if you reproduce earlier
F in breeding depression is caused by deleterious recessive mutations and if late acting deleterious mutations are maintained at a higher frequency than the severity of inbreeding depression increases with age
Antagonistic pleiotropy hypothesis
Use the benefits while you’re young, maturation earlier. If you breed early you don’t live as long but if you breed late you still have the same reproductive success and you live longer
Ecological mortality
Lower rates of ecological mortality will evolve delayed senescence (evolutionary theory of senescence)
If you don’t know if you’re going to live they’ll reproduce earlier but if not in danger of dying they’ll wait till later and put same investment in first year as later years of babies
Lack’S hypothesis
Selection will favour clutch size that produces the most surviving offspring. This is not supported because it assumes no trade-off between a parents reproductive effort in one year and it survival or performance in future years, assumes only effect of clutch size is whether offspring survive
