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Evolution of Aging

This examination of the evolution of aging explores senescence, artificial selection effects on lifespan in fruit flies, and trade-offs in reproductive strategies. Key theories include the Mutation Accumulation Hypothesis and the Antagonistic Pleiotropy Hypothesis, which explain how genetic factors influence aging. The study also discusses the role of environmental conditions on longevity and reproduction in various species, including sockeye salmon and collared flycatchers. The implications of these findings for human reproduction and aging, including menopause, are also considered in this comprehensive overview.

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Evolution of Aging

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  1. Evolution of Aging

  2. I. Evidence for senescence and evidence for the evolution of senescence

  3. Artificial selection increases life span in fruit flies Inherent limits, or can lifespan evolve? Fruit fly expt:

  4. II. Fundamental Trade-offs Female sockeye salmon defending its nest before dying

  5. Mite Kiwi bird

  6. The life history of a hypothetical female Virginia opossum (Didelphis virginiana)

  7. III. Evolutionary theories of aging Background: Expected Reproductive Success (RS) = Prob(Surviving) x #(Offspring)

  8. Versus 2.419

  9. Versus 2.419

  10. Two Theories • Senescence reflects relaxed selection (drift) • increased expression of deleterious recessive alleles • increased genetic variation later in life • B. Senescence reflects tradeoffs • loci involved in senescence have early fitness effects • balancing selection signature

  11. Mutation Accumulation Hypothesis (drift, non selection) • Mutations expressed later in life, near the end of reproduction • are effectively neutral

  12. B. Antagonistic Pleiotropy Hypothesis The longevity allele hx546 under (a) benign and (b) stressful conditions

  13. Trade offs in fruit flies between longevity and reproduction

  14. Collared flycatchers: (a) natural variation and (b) experimental manipulations Extra eggs

  15. Differences in mortality Differences maternal ability Physiological deterioration

  16. IV. Evolution of Senescence and Human Reproduction

  17. Functional capacity of various physiological systems in women as a function of age from Ache hunger-gathers of Paraguay

  18. Menopause an artifact of living longer?? Probably NOT

  19. Hazda Woman (hunter-gatherer from East Africa)

  20. Conclusion All organisms die The timing of reproduction and death can evolve Two evolutionary theories of senescence: Mutation Accumulation & Antagonistic Pleiotropy Human Menopause may be explained by inclusive fitness

  21. Adult house flies only allowed to live 4 days

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