evolution of aging katy nicholson and coco shea. why do organisms age?
TRANSCRIPT
![Page 1: Evolution of Aging Katy Nicholson and Coco Shea. Why do organisms age?](https://reader033.vdocuments.us/reader033/viewer/2022051401/5697bf721a28abf838c7e89b/html5/thumbnails/1.jpg)
Evolution of AgingEvolution of Aging
Katy Nicholson and Coco Shea
![Page 2: Evolution of Aging Katy Nicholson and Coco Shea. Why do organisms age?](https://reader033.vdocuments.us/reader033/viewer/2022051401/5697bf721a28abf838c7e89b/html5/thumbnails/2.jpg)
Why do organisms age?
![Page 3: Evolution of Aging Katy Nicholson and Coco Shea. Why do organisms age?](https://reader033.vdocuments.us/reader033/viewer/2022051401/5697bf721a28abf838c7e89b/html5/thumbnails/3.jpg)
• Decline in individual’s fertility and probability of survival
• Lose ability to completely repair mutations in cells and tissue (lack of energy)
• Decline in individual’s fertility and probability of survival
Definition of Aging (Senescence)Definition of Aging (Senescence)
• Decline in individual’s fertility and probability of survival
• Lose ability to completely repair mutations in cells and tissue (lack of energy)
• Decline in individual’s fertility and probability of survival
![Page 4: Evolution of Aging Katy Nicholson and Coco Shea. Why do organisms age?](https://reader033.vdocuments.us/reader033/viewer/2022051401/5697bf721a28abf838c7e89b/html5/thumbnails/4.jpg)
• Populations lack the genetic variation necessary to respond to selection against aging
• Populations lack the genetic variation necessary to respond to selection against aging• Telomeres are shortened every time a cell divides (Harley et al. 1990)
Rate of Living TheoryRate of Living Theory
• Telomeres are shortened every time a cell divides (Harley et al. 1990)
• Populations lack the genetic variation necessary to respond to selection against aging
![Page 5: Evolution of Aging Katy Nicholson and Coco Shea. Why do organisms age?](https://reader033.vdocuments.us/reader033/viewer/2022051401/5697bf721a28abf838c7e89b/html5/thumbnails/5.jpg)
• Less selective pressure on deleterious mutations after reproductive age
• Accumulation of deleterious mutations after reproductive age
• Neutral alleles can drift to fixation
Evolutionary Theory of AgingEvolutionary Theory of Aging
• Accumulation of deleterious mutations after reproductive age
• Less selective pressure on deleterious mutations after reproductive age
• Accumulation of deleterious mutations after reproductive age
• Less selective pressure on deleterious mutations after reproductive age
• Accumulation of deleterious mutations after reproductive age
• Neutral alleles can drift to fixation
![Page 6: Evolution of Aging Katy Nicholson and Coco Shea. Why do organisms age?](https://reader033.vdocuments.us/reader033/viewer/2022051401/5697bf721a28abf838c7e89b/html5/thumbnails/6.jpg)
Evolution of Shorter Life Span:Accumulation of Deleterious Mutations
Fig. 12.11 Houseflies - Reed and Bryant (2000)
![Page 7: Evolution of Aging Katy Nicholson and Coco Shea. Why do organisms age?](https://reader033.vdocuments.us/reader033/viewer/2022051401/5697bf721a28abf838c7e89b/html5/thumbnails/7.jpg)
Energy Trade-OffsEnergy Trade-Offs
• Antagonistic Pleiotropy Hypothesis – Mutation allocates energy to early reproduction or late death
• Reproduce Early or Reproduce Longer?• Reproduce Early or Reproduce Longer?• Antagonistic Pleiotropy Hypothesis – Mutation allocates energy to early reproduction or late death
• Reproduce Early or Reproduce Longer?
![Page 8: Evolution of Aging Katy Nicholson and Coco Shea. Why do organisms age?](https://reader033.vdocuments.us/reader033/viewer/2022051401/5697bf721a28abf838c7e89b/html5/thumbnails/8.jpg)
• eg. Nematode: Caenorhabditis elgans (Walker et al. 2000)• eg. Nematode: Caenorhabditis elgans (Walker et al. 2000)
Fig. 12.12
Antagonistic Pleiotropy HypothesisAntagonistic Pleiotropy Hypothesis
![Page 9: Evolution of Aging Katy Nicholson and Coco Shea. Why do organisms age?](https://reader033.vdocuments.us/reader033/viewer/2022051401/5697bf721a28abf838c7e89b/html5/thumbnails/9.jpg)
ConclusionConclusion
• Aging is accumulation of deleterious mutations• Allocate energy to reproducing early or to repairing cells later
• Aging is accumulation of deleterious mutations• Allocate energy to reproducing early or to repairing cells later
• Aging is accumulation of deleterious mutations