Reproductive Behaviour Flashcards
what is sexual selection
form of natural selection when individuals vary in their ability to mate and reproduce
- traits that increase success can evolve
two components of sexual selection
- intrasexual selection (within same sex)
- competition among individuals of same sex (usually male) - intersexual selection (between the sexes)
- involves mate choice based on certain traits (usually females r choosing)
isogamous sexual reproduction
fusion of gametes that are the same size
anisogamous sexual reproduction
reproduction between sexes with different sized gametes
male gametes ____ limitless and vary based on what
aren’t
- vary based on number of copulations & parental ages
bateman’s principle
there is a variance in mating success between the sexes
- more variance in males
males: success based on # of mates
females: based on # eggs / offspring they can produce
sexually selected traits (2) orn vs arm
- attracting mates (ornaments)
- fighting for mates (armaments)
sexually selected traits are ____ meaning what
plastic, meaning they can change
what are two alternative mating tactics other than competition
sneakers - mate while dominate male is distracted
parental males - invest care to make females like them
good genes model
mate choice is based on wanting increased genetic quality of offspring
- females get attractive sons
- disease resistance
Zahavis hypothesis
only good quality males can afford elaborate ornaments and displays
Hamilton & Zuk
sexual displays signal genetic resistance to diseases
describe hormones and ornaments
testosterone develops showy traits BUT also suppresses immune system so healthiest males can do both!!
- honest signal of genetic quality
females want males with ___ immune genes to maximize _____ in offspring
males with different immune genes
maximize heterozygosity in offspring
females want good ____ and good ____
good genes & good resources
flucuating asymmetry is linked to _____
not as good genes/ development
cryptic female choice
happens AFTER mating - influence fertilization via their reproductive tracts (store multiple males sperm)
- tracts could pose obstacles for sperm
- females can remove or displace sperm of rival males
3 ideas for multiple mating in females
- less harassment
- increase fertility
- better genetic quality
describe EPF
extra pair fertilization
- has a social partner (raises) & extra pair mate (mate)
- get good genes from extra pair mate as a backup
