chapter 7 Flashcards
what do male bowerbirds do around their nests
surround it with trinkets: leaves,
bones, shells, acorns, berries, fruits, and shiny rocks to man-made
bits like beads, glass, and bottle caps—all neatly placed and
arranged by the male. Within and around these nests, males perform
elaborate behavioral displays to solicit mating opportunities from
females who visit
bowerbirds optical illusions
a scene from the environment, when projected onto the two
dimensions of the retina, differs from the actual three-dimensional
reality of that scene in nature. avenue nests have gesso which makes objects appear bigger than they really are and then they get more mating opportunities
batemans principle
fruit flies
(1) females should be the choosier sex because eggs are expensive
to produce and because a female’s potential reproductive success is
limited compared with that of a male, and (2) females’ greater
choosiness in mate selection should translate into greater variance in the reproductive success of males
Up until the 1970s, which part of sexual selection was talked about more?
intrasexual rather than intersexual
what is an epigenetic trait
a secondary sex characteristic
is sexual selection stronger in monogamous relationships or polygynous relationships
polygynous due to greater variation in reproductive success
what are the four evolutionary models for female mate choice
direct benefits, good genes, runaway selection, and sensory exploitation
what does direct benefit of mate choice mean and how scorpionflies do this
selection favors females that have a genetic predisposition to prefer mates that provide them with tangible resources like food shelter, parental care assistance, increasing fecundity
ex: scorpionflies and nuptial gifts (choose mates that gifts during courtship) In scorpionflies, it’s large prey items that females can then eat. The smaller the gift, the shorter the amount of time the male has to mate; the female will pull away, and less sperm will transfer. No gift means no mating. The gift leads to more egg production and a longer life for the female.
what do good genes of mate choice mean
Good genes, also known as indirect benefit models, are those that are associated with adaptive traits inherited by offspring of the appropriately choosy female.
females choose males with genes best suited to their environment
pronghorns: a good gene is harem defense
honest indicators: costly traits (harder to fake) ex: resistance to parasites, colorful means healthy, greater number of MHC alleles (disease defense)
runaway sexual selection
Certain male traits can evolve rapidly due to female preference for those traits, even if the traits initially confer little survival advantage. ex: stalk eyed flies
sensory bias and mate choice
when a male trait first emerges, it is preferred by females because it elicits a neurobiological response
that is already in place in females, and that such a response initially
is not associated with mating preferences.
ex: birds like red berries if males develop red feathers they will be preferred because theres a genetic predisposition
ex: frogs and components of calls
what happens to males after exposure to a sexual stimulus
males are quicker to copulate, become better competitors with other males, display higher levels of
courtship, and produce more sperm and progeny
if an offspring is raised with its parents for the first month and then put in isolation for 2 months, what will he imprint on
the phenotype of the first female he encounters
can a receptive mate override the effects of sexual imprinting
yes
in what age group does mate choice copying occur
younger females that are around more females
what hormone may be responsible for mate choice copying in mice
oxytocin
knocking out the gene for oxytocin has the specific effect of inhibiting mate-choice copying behavior
testes size in relation to sperm
the bigger the testes, the more sperm per ejaculate
