Evolution Week 12 Flashcards
What are 3 hypotheses about female choice for exaggerated male trait?
Arbitrary choice, good genes and fisher(good genesprocess)
What is arbitrary choice?
A trait that is attractive to females. Genetic association between a female preference and a trait leads a positive feedback cycle.
What is good genes?
Ornaments may indicate that males are able to live with costly “handicaps” and are thus healthier.
What is the Fisher hypothesis?
Alleles for female preferences can coevolve with alleles influencing expression of costly indicator traits in males.
___________ traits are more reliable indicators of male quality
Costly display
What is polygyny and give an example.
Males mate with multiple females. Racoons and lions.
Define monogamy and list the 2 subdivisions.
One male pairs with one female;
Sexual: partners mate with each other exclusively
Social: partners pair but may cheat
Define polyandry. Give an example.
Females mate with multiple males. Grasshoppers.
The preference for the trait of a female can lead to what?
Leads to stronger preferences and larger display traits.
What is discriminating (clumping) sperm? (In deer mice)
Sperm from same male will group and swim together.
Give examples of sexual conflict.
Giant sperm introduced to prevent other sperm from entering (Drosophila).
Cryptic female choice: when females store and separate sperm from different males (bees)
Define sexual conflict.
Traits that confer a fitness benefit to one sex but a cost to the other. Traits coevolve antagonistically
List the key concepts.
Mating systems evolve because of the benefits and costs they confer on males and females.
Polyandry leads to sperm competition among males.
Sometimes females can control whose sperm fertilizes their eggs.
Sexual conflict leads to antagonistic coevolution between males and females
