ch. 12 evolution of life history and parental care Flashcards
Life History
the investment an organism makes in growth and reproduction
Natural selection optimizes ____.
life history in light of trade-offs
What drives the life history evolution in guppies?
predation risk
Trade-off between ____ and _____.
reproduction, growth/survival
Trade-offs
-arise when investment in one trait results in lower investment in another trait
**similar to patterns of antagonistic pleiotropy
What is an example of sex role reversal?
Wattled jacanas because females compete over access to males
Other examples of sex role reversal:
pipefish, seahorses, and other species in family syngnathidae
Organisms may regulate the number of offspring to maximize fitness
-miscarriage
-cannibalism (male sand guppies)
Organism may regulate the ____ to maximize fitness
sex ration
Can species switch sex in trivers-willard-predicted manner?
yes, they start as females and breed as such when young and small but switch to male when they are large
Frequency-dependent selection maintains ____ within populations.
variation
Parental care creates opportunities for many kinds of conflicts:
-between parents
-among siblings
-between parents and offsprings
-sexes may maximize fitness differently
_____ benefit when mother invests more in current offspring. ____ benefit by saving resources for future offspring.
Males, Females
Postponing senescence is…
-calorie restriction can slow the aging process
-may involve trade-offs
-senescence results from a trade-off: reproduction early in life versus body maintenance for longevity
Mother Hypothesis
risk of reproduction at older age selects for reduced fertility
Grandmother Hypothesis
loss of fertility associated with shift in investment to grandchildren
Menopause evolved ___ humans diverged from other apes.
after
(may be an adaptive trait)
OSR is skewed towards females when
-males are required to nurture and bear offspring
-females are only limited by number of mates
Under what condition would natural selection favor a mutation that is beneficial early in life but is harmful later?
high extrinsic mortality rate that keeps organism from reaching an old age
In a polygynous species, the Travers-Willard hypothesis suggest that offspring sex ratios ?
a female in good condition may produce more sons than daughters
