Lecture 20: Life Histories Flashcards
Define fecundity
is the actual reproductive rate of an organism or population, measured by the number of gametes (eggs), seed set, or asexual propagules.
Understand the live fast, die young vs. live slow, die late.
In some environments one of the other will be more beneficial
Understand life history trade-offs.
There is a fitness trade-off between the increased survival of the offspring and parent and the parental investment
What is reproductive value Vx?
the contribution to future generations by an individual of age x
What are the trends of reproductive value?
- The reproductive value is high at young ages
- The reproductive value declines with increasing age, risk of mortality increases
- Strength of natural selection decreases with age
Understand the trends for lifetime reproductive success.
Some mutation that favor early reproduction and early death can be favored
What are the theories of aging?
- Rate of living hypothesis
- Mutation accumulation
- Antagonistic pleitropy
What is the rate of living hypothesis?
There is wear and tear and the best repair system has already been created, longevity should be correlated with metabolic rate, but data does not support consistent correlation
- Big animals live longer, but have lower matabolism
How can two animals have the same body size, same metabolic rate, but different life spans?
There are other factors at play such at predation.
What is the mutation accumulation hypothesis?
Mutation “causing” decay at late age accumulate due to weak selection opposing them, accumulate due to drift
What is the antagonistic pleitropy hypothesis?
Mutation increasing early-age reproduction have a negative trade-off off increase risk of death at late age. Selection increases these alleles when selection is strong, but cannot remove them at late age.
Defin pleitropy
A gene with multiple effects
