Sexual Selection Flashcards
Sexual selection
a special case of natural selection related to the evolution of sexual characteristics
Primary sexual characteristics
differences in male and female genitalia
Secondary sexual characteristics
traits that attract mates competition or attraction
Intrasexual competition
same sex competition for mating/reproduction
Intersexual competition
members of one sex choose the opposite sex member for mating/reproduction
What are the 3 principles of Bateman’s principle?
1) females are choosy & males are indiscriminate
2) variation in male reproductive success
3) degree of parental investment is inversely related to reproductive success (defined as total number of offspring produced during the selection episode)
Sex with greatest investment has least __________ in reproductive success
variability
Investment in each offspring is _________, thus increase in one results in _______ in another
independent
decrease
What is included in the total parental investment per season?
sum of investments in all offspring
Average investment
total investment divided by the # of offspring
How is the degree of sexual competition in males calculated?
the ratio of the number of offspring
Sexual selection is strong in __________ and ____________ species
Polygamous
Polyandrous
________ __________ in reproductive success increase sexual selective pressure for secondary sexual characteristics
Greater variation
Promotes _________ selection for traits size or signal intensity
directional
What are the 4 classes of evolutionary models based on female choice?
1) direct benefits
2) good genes
3) runaway selection
4) sensory exploitation
Unifying theme of female mate choice theory is that choice is under ______ _______, thus _________ is linked to reproductive success
genetic control
behavior
What is one example of direct benefits in mate choice?
scorpion flies providing nuptial gifts in the form of food during mating
What is one example of good genes in mate choice?
pronghorn antelope females selecting males based on harem defenders (on with most favorable traits)
What does Zuk-Hamilton’s model of parasite resistance state?
traits are true indicators of genetic quality are superior
When and who devised the model of male fitness?
in 1982 by Kirkpatrick
Females come in two __________ based types and the elaborate male trait is _________ based.
genetically x2
What is an example of a sensory bias and mate choice?
preference in frog mating call (Ryan in 1990)
chose low frequency call over normally selected mating call
Male trait is preferred initially because it elicits a prior held sensory/neurobiological bias, then it becomes associated with mate choice secondarily. What model does this represent?
sensory bias and mate choice
Sexual imprinting
early social experience that affects species recognition in adults during courtship and mating
What are the 3 types of imprinting?
1) Filial
2) Sexual
3) Chemical
Filial imprinting
following response, preference for imprinted object
Sexual imprinting
mating preference
Chemical imprinting
site preference, usually for egg laying
Mate-choice copying
female preferences is affected other female choice in the population
Who found out that in grouse leks had a correlation between number of matings and tendency for females to copy?
Gibson in 1992
Intrasexual selection processes are ____ risk among competitors.
high
Male’s reproductive success in red deer is dependent with _____ ____ and _____. Discovered in 1982 by _______-______.
> body size
age
Clutton-Brock
Curvilinear function
immature and older males show lower reproduction rates than males at peak physical fitness
Male-male competition by interference
female incite male competition to increase probability of mating with high ranking males
_________ comparison shows association between sexual dimorphism & harem size in pinnipeds
Phylogenetic
