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BGYB51H3 Lecture 23 Notes Nov 26

Biological Sciences
Course Code
Maydianne Andrade

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BGYB51H3 Lecture 23 Notes
-evolutionary hypothesis of aging says that aging is caused by failure organisms to completely
repair cell and tissue damage
-there is weak selection against mutations on older organisms
-positive early effect on reproduction is favoured by natural selection and usually outweighs
negative effects
-mutation accumulation hypothesis and repair-reproduction trade off hypothesis are part of
the evolutionary hypothesis of aging
-mutations that decrease the ability of organism to maintain body in good repair are evident as
the organism ages
early in life
-mutations may be maintained through mutation-selection balance if selection is weak during
late years
-deleterious mutations early in life are eliminated
-repair-reproduction hypothesis is the antagonistic pleiotropic hypothesis
-mutations that increase lifespan lead to decreased early reproduction (vice versa)
-reproducing early comes with the cost of less offspring compared to late reproduction
-early reproduction causes increased senescence when adding eggs to the nest
-ecological mortality is mortality caused by extrinsic factors
-senescence is changes in function caused by intrinsic factors
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