Flashcards in Sexual Selection Deck (31):
Critical to natural selection
selection arising from differences in mating success
Selection arising from competition between or within sexes in a single population
Features which enhance relative fitness and thus lead to greater reproductive success
Materials For Selection
Differences in phenotype that have consequences for survival and reproductive success
Copulation (reproductive model)
Individuals recognize and encounter conspecifics of the appropriate sex
Means of transmitting gametes
requires time and energy searching for mates
number of potential encounters may be limited so each copulation potentially limits future choices or opportunities
Spawning (reproductive model)
Coordination of members of population with respect to timing of spawning
typically prevents extensive parental care
concentration and density of gametes appropriate to environment
gamete recognition mechanisms
oldest and largest individual is a female, males compete for access
- better guarantee of successful reproduction
- promote competition among males and among their sperm --> more variation possible
- multiple males can procure more resources for the female
Oldest and largest individual is a male, maintains group of females
males maximize mating opportunities
sexual selection between members of one sex for access or opportunity
preference by one sec for certain phenotypes in mates
what is assortative mating? what two types are there?
contrast to random mating
positive assortative mating and negative assortative mating
Positive assortative mating
preference for similar phenotype (possible inbreeding)
Negative assortative breeding
preference for different phenotype
may make it hard to maintain species boundaries
what are the components of reproductive fitness?
Who typically picks for mating
pretending to be females
Having multiple mates
Zahavi Handicap hypothesis
extravagant male morphologies means the male has passed the "test" and males without haven't
female preference for extreme morphology is therefore a preference for higher fitness males! WOW
Test done showing females prefer the longest tail
Runaway Sexual Selection
female choosiness and male elaboration form a positive feedback loop --> the females like long tales so males keep making their tails longer and longer
male appearance and fitness become de-coupled; extreme morphology NOT correlated with higher fitness
female's choice NOT a guarantee of better genes for her offspring
what are two basic kinds of reproductive modes?
copulation and spawning
what HW requirement does sexual selection violate?
demonstration of mate preference violates the random mating tenet of HW
AND that all offspring have an equal chance of survival and reproduction because if mate choice is based on heritable phenotype then some offspring will have a greater/lesser chance of reproducing
what is viability?
probability that individual bearing genotype will survive
what is mating success?
number and quality of mates
what is fecundity?
number of gametes per individual
what is segregation advantage?
alleles wind up in the games more/less frequently
what is gamete viability?
alleles impact the longevity or quality of the egg or sperm
what is fertilization success?
alles impact the probability that fertilization will take place
why do females typically do the picking?
females produce the expensive gametes --> may also have post-mating responsibilities
female strategy is typically focused on obtaining the best mate so that HER investment in eggs pays the greatest genetic dividend --> higher proportion of offspring survive and reproduce
what kinds of things typically act as cues in female choice?
features that suggest health and capability in feeding
features that emphasize distinction between males and females
novelties that suggest that males are from another population