Sexual Selection Lecture Flashcards
What are sensory biases?
Sensory systems evolved under many selection pressures such a sfinding food, avoiding predators and individual recognition. Females may have sensory biases such as colour preferences that males exploit in their sexual signalling.
What is an example of a sensory bias?
Male Tungara frogs call to attract females and calls can be whines or chucks. Sensory biases pre-date this tree where males only had whines but females also prefer calls with chucks. Some males now have whines and chucks and females prefer the calls with chucks.
What is anisogamy?
Males can produce more gametes than females therefore females become a limiting resource for mates. This has effects on behaviour with females increasing their reproductive success through quality, and males increasing theirs through quantity.
What benefits can females get from males?
Indirect and direct benefits. Indirect benefits are genetic benefits which increase the survival or sexual attractiveness of the offspring. Direct benefits benefit either the female or offspring directly such as parental care.
In which ways can males provide genetic benefits for offspring?
Through better survival and better reproductive success.
What is the handicap principle?
This was proposed by Zahavi (1977) and suggests that females choose males on the basis of exaggerated traits because only males with good genes can exress them.
What are revealing handicaps?
Maynard Smith (1991) proposed that handicaps might not be costly to produce, because signals can’t be given unless the signaller has the trait they are signalling about.
What is the sexy sons hypothesis?
This was suggested by Fisher (1930) which proposes that a females optimal choice among potential males will by those whose genes will produce male offspring with the best chance of reproductive success.
What does Fisherian runaway selection explain>
How traits evolve which do not indicate good quality but because they are attractive to females. Offspring of females choosing these traits will have the preference for the trait from their mother, and the expression of the trait from their father resulting in a positive feedback loop.
