Flashcards
Sexual Selection
Cards in this deck (31)
- 1Sensory Bias Hypothesis /Sensory Exploitation /Pre-existing Bias 2Female initially prefer male trait initially not because of any mating benefit associated with trait, but because associated with some benefit outside of mate choice/artifact of how wired
Eg preference for red berries = pref. for red colour = pref. for sexual dimorphism - 2Sensory Bias Hypothesis Testing the Hypothesis 4Female preference predates appearance of male trait
Use two types of tail yellow/transparent
Female prefer males with artificial swords over ones without
Common ancestor swordless = pre-existing bias - 3Pre-copulatory Intrasexual Selection 4Grasshoppers Sphenarium purpurascens male fighting
Strong assortative mating large males with large females
Males fight before and during copulations
Large females produce more eggs than small females = more valuable - 4Fitness Definition 1Ability of an individual to survive to reproduction
- 5Cuckoldry Bluegill Sunfish Behaviour Pre-copulation 7Leponis macrochirus
Different mating stratergies
Parental males - prepare nest
Sneaker males - opportunistic mating
- intervene once mating had started and release sperm quickly
Satellite - mimic female form
release sperm when other male does
Common in salmon as well - 6Cuckoldry Bluegill Sunfish Behaviour Testes 5Ratio of testes to body sizes - ratio of testes to body size
Sneaker > satellite > parental
Bigger testes = more sperm produced
Sneaker = many shirt-lived sperm, low quality
Parental = few high quality sperm - 7Absolute Fitness 1Average number of offspring produced of offspring of past genotype
- 8Darwin's Nightmare 7Peacock tail makes me feel sick
Trait selected by INTERSEX sel.
Costly to produce = male genetic quality
Male with elaborate trains = healthier chicks
= higher survival rate
Positive correlation
Large spots = higher MHC diversity - 9Human Sexual Selection 6PASTORLIST WODAABE PEOPLE
Fulani ethic group
Fully normadic
Gerevol ceremonies - end of rainy season celebration
<1000 men participate to be judged by 3 women
Females choose husbands - 10Sex.Sel. Importance in Evolutionary Context Relative Fitness 1Average number of offspring produced by individuals of a part genotype RELATIVE to other numbers of the populaiton
- 11Human Sexual Selection Three Dances 3RUUME - daytime dance of welcome and nighttime dance of seduction
YAAKE - competition of charm and personality
GEERENOL - birthright of beauty handed down by ancestors - 12Descent of Man and Selection in Relation to Sex Charles Darwin 1Competition within the species where selection factor is the opposite sex
- 13Human Sexual Selection Polygyny 5Multiple wives
1st relative
2nd love
Daughters of previous choices choose 1st wife
= runaway effect - 14Two Components of Sexual Selection 2Female and males differ in structure/colour/ornament caused by S.S. for slight advantage over other males
Female influenced by male traits eg colours - 15Intersexual Selection 2One sex selects among the other sex as mates
ATTRACTIVE TRAITS - 16Intrasexual Selection 2Males compete with each other for mating with other sex
PRE- AND POST- COPULATING TRAITS
ADVANTAGE IN COMPETITION - 17Wallace View on Sexual Selection 6Didn't believe in Sex.Sel.
Male-male fighting = natural selection
Male plumage = vitality
Sexual dimorphism = natural selection
ABNORMAL GROWTH - Surplus of vital energy - 1889
Changed view - display of ornament to excite desire - 1892 - 18Sex. sel. Starting Points 4Sexual reproduction - selection against deletions
- sexual population have genetic variance
Red Queen Hypothesis - sex.sel. advantage because recombination = new gene combination resistance to para.
Predator vs Host - 19Sexual Starting Points Anisomy 6Diff. gamete sizes
Product of natural selection
Assume fitness of zygote increases with increasing size
DISRUPTIVE SELECTION = diversifying selection = evo. stable strat.
Females = few and large gametes
Males = many and small gametes - 20Sexual Starting Points Anisomy and Sexual Conflict 5Different cost for production
Conflict between evolutionary interests
Males - want to mate with lots of females
Females - mate witht eh best possible male to maximise fitness of offspring
DIVERGENT PHENOTYPIC BEHAVIOURAL TRAITS - 21Types of Mating System 41m and 1f = Monogamy
>1f and 1m = polygyny
1f and >1m = polyandry
>1f and >1m = polygynandry - 22Dunnocks 9Victorian symbol for faithfulness
All mating systems in one pop.
No sexual dimorphism
Both act as parents
Females try to mate with more than one male
Males cannot tell own offspring from other males = care for all
Dom male pecks at genitalia to expel sneaker male sper
'Extra pair male' genetically better than dom male is hard to tell
Beta male sire beta males - 23Song Sparrow 5Melopiza melodia
Survival of extra pair and within pair offspring
15yr study
Look at survival of chicks
Average - no diff. in survival - 24Intersexual Selection 3Mate choice with other sex
Ori. of experimental characters
4 evolution models - 25Direct Benefits Model 4Dunnocks model
Male feed all female chicks
Amphipod Hyalella azteca
Probability of females being captured by predator decreased with increasing size of males she chooses to mate with - 26Indirect Benefits Model Sexy Son Hypothesis Fisher 8Benefit from alleles affecting female mate choice increasing/decreasing in freq. depending on fitness
of female offspring
SEXY SON HYPOTHESIS - sons of female choose a male trait that improved mating success as inherited trait that made father appealing
Male trait - indicates high viability inherited by offspring
SELF-REINFORCING - evolution of male trait and female preference
Genetic correlation between. female preference and trait
Linkage disequilibrium between alleles for male phenotype and allele for female preference
Population diverge in mate choices
= may become reproductively isolated - 27Sexy Sons / Runaway Sexual Selection 4Hummingbirds and birds of paradise - high level of sexual dimorphism
- lots of species
Bigger number of species of hummingbirds (319 spp) compared to sister clade swifts (103 spp)
Bigger number of species of birds of paradise (33) compared to sister clade manucodes (5) - 28Handicap Models 3Male trait correlate with high genetic quality indicator
Guidance for females to advantageous mating
Honest trait condition dependent indication of fitness - 29Issues of Good Genetic Model of S.S.DISTINCTION between good model and runaway s.s. model is DIFFERENT
Good model - female preference not evolved to point determined to fit
Good genes model - s.s. dec. var. in fitness - 30How to maintain genetic variation with a s.s. population 2New mutations
HAMILTON-ZUK: contain variance in parasite load will maintain variance in resistance traits in population of hosts with honest trait indicators of resistance to parasite - 31Genetic Significance of Indirect Benefit of Mate Choice 8Significance of selection detected by gene controlling colour
Male and female colour different
Gene linked to colour - Mc1R
Look at seq. of Mc1R gene in birds dn/ds
dn/ds - proportion of non-synonymous mutation in a gene against proportion of synonymous mutation
Compare sister spp. - expect big dimorphism (large dn/ds)
No difference - female and male of dn/ds and sexual dimorphism
= CHOICE OF FEMALE HAS IMPACT ON EVOLUTION OF GENE
Information
- Description
- Degree Evolutionary Biology of Animals Flashcards on Sexual Selection, created by katy.lynock on 23/05/2013.
- Created by
- katy.lynock
- Views
- 59
- Tags
- Rating