evolution of sex Flashcards
what are the dangers of sex?
STIs
risk of predation
time and energy
what are the key hypothesises for explaining origins of sex
masking deleterious mutations
recombinaion DNA repair
what can happen if we didnt have sex>?
deleterious mutations can accumutate and the good alleles lost through drift
genetic variation lost
population may go extinct
hypothesises for keeping having sex
recombination brings together favourable alleles
red queen: coevolutionry arms race
what evolved ansiogamy?
disruptive selection
this is the trade off between gamete number and size
how does disruptive selection work
zygote viability favoured by large gametes
fertilisation sucesses favoured by small gametes
what drives gamete differentiation
sperm competetition
what is genome dilution
a consequence of sex
cost of ansiogamy
what are the consequences of sex
genome dilution
sexula selection
sexual conflic
what is the frequency dependent selection
rarer sex does better and has a higher reproductive sucess
evolutionary stable strategy
what does the fisher null model say
sexes are equal and they ranomdly mate
what does maternal investment depend on?
mothers rank or physical condition
higher rank females should make sons as they are fitter
what is the Trivers-Willard model
sons benefit more than daughters from extra maternal resources
maternal investment in offspring depends of mothers rank or physical condition
what is local mate competitiion
sex rations depend on numbers of females entering each patch
it makes no sense for sex ratios to be equal
which wasy a sex rations favoured
female biases
the bias decreases as the number of foundresses per pathc increases, it becomes a more bigger, less structred population
how do females detemine the sex ratios of offspring?
haplodiploidy
she controls the selective fertilisation of eggs
what promotes long term survival
recombination
even through sex is costly, this helps
what maintains an equal sex ratio
frequency dependent election maintains the equal ratio
except there investment costs in sons and daughters difffer
