Exam 3: Evolution of Aging

Question 1

Why does mortality occur?

Answer 1

-predation, accidents, natural disasters, etc.

Question 2

Extrinsic Mortality

Answer 2

mortality from outside force

Question 3

Aging and its effects

Answer 3

Aging: progressive, intrinsic loss of function with age
Effects: decreasing fertility rates & increasing mortality rates

Question 4

What is key about aging and natural selection?

Answer 4

Natural selection is weak against deleterious effects occurring late in life b/c likely to be dead & done reproducing

Question 5

Aging Hypothesis One: Mutation Accumulation

Answer 5

-> alleles w/ deleterious effects late in life become fixed through drift
As individual approaches sexual maturity-> probability of reproduction increases at reaches its peak, but probability of death also increases b/c of predation, disease, etc.
So.. probability of reproduction decreases after reaching peak

Question 6

Aging Hypothesis Two: Antagonistic Pleiotropy

Answer 6

-> pleiotropic (multiple effect) genes that confer
Beneficial early acting effect & deleterious late acting effect

Question 7

Life History Traits

Answer 7

growth rate, age, size, sex ratio of offspring, etc.

Question 8

Increase in life span if…

Answer 8

-reduce extrinsic mortality
- select for later reproduction