Study Questions - Aging
Readings - chapter 13
1) The 'rate of living' hypothesis assumes that repair enzymes are as efficient as possible. Why do mutations increase over time then? How has this hypothesis been tested empirically, and what are the conclusions?
2) How does the 'cell division hypothesis' differ from the 'rate of living' hypothesis? When C. elgans are constructed with longer telomeres, does lifespan increase? Curiously, in natural populations, we do not see telomeres this long. Provide two hypotheses why they might be absent from natural populations.
3) We see long telomeres in stem cells and cancer cells. Describe Tyner's experiment and provide an explanation for the results that gets at the balanced selective pressures that might be at work.
4) Describe the results and conclusions of Heidinger's experiments with Zebra Finches.
4) Describe Hughes experiment (book), and explain why certain crosses produced higher degrees of inbreeding depression, and how this bears on the 'mutation accumulation' hypothesis.
5) Why does early reproduction have a more dramatic benefical effect on lifetime fitness than living and reproducing for more years at the end of life? Explain this in the context of kin selection and 'inclusive' fitness.
6) One of the most dramatic correlations with the hypothesis, above, involves the effect of young grandmothers on the reproductive success of their daughters. Describe two correlated patterns that suggest positive effects on the daughter's (and-by extension-the grandmother's) fitness.