CH. 7 (Week 3-Lec. 2)
Terms in this set (29)
Differences in physical characteristics between males and females of the same species.
primary sexual characteristics
organs specifically needed for reproduction
secondary sexual characteristics
physical signs of sexual maturation that do not directly involve sex organs
A form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates.
-affect an individual's success in competing for mates, attracting mates, or competing for fertilizations during or after mating
reproductive rate x longevity
Darwin's theory on sexual selction
theorized that unique traits could evolve that lowered survival chances if they helped an individual gain advantage in acquiring mates
Bower bird mating strategies
-male build a burrow/nest full on random items to attract female
honest signal - bower bird
-By building the bower
-Male is showing he has
-Blue is rare
-He lacks ectoparasites
-female is only interested in his sperm
sexual differences theory
-males commonly try to mate with many females
-females mating with only males
-females are choosy
-men and women different in the number of sexual partners that they say they would ideally like to have over different periods of time
the time and energy parents expend for their offspring's benefit
-females invest more than males usually (certainty in offspring being hers, male does not know certainty)
sex role reversal
where the male are choosy and the females are competing for mates.
-sex that invests most is a limiting resource for the sex that invests the least
A food item or other item presented to a potential mate as part of courtship.
important factors of sexual role reversal
-operational sex ratio
seasonal changes in the sex roles
as the environment changes so does the behavior
-a pouch in certain fish, frogs, and invertebrates in which the eggs are protected before hatching
-Females transfer the eggs and male cares for them
-Male is involved in procuring resources in the beginning to feed their offspring
example: Sea horses, penguins, pipe fish, etc.
operational sex ratio
the ratio of male to female individuals who are available for reproducing at any given time
-How many females are available in the environment compared to males in the environment
what is there convergent evolution in when it comes to reproduction?
-Ex: Dominant male gets more access to the females
The coexistence of two or more distinct forms in the same population.
-morphs must occupy the same habitat at the same time and belong to a mating population
-different genetics essentially causes an alternative stable strategy
what happens when the operational sex ratio comes into play?
the less receptive sex gets to be choosy
baboon alternative tactics for mating
-subordinate males can and do develop friendships with particular females
-once he has showed to protect her offspring, she will seek him out as she enters estrus
-grooming is common in primates
-essentially dominant male baboons do not control the fertile females as completely as would expect (lower ranked males mate in secret)
what are the baboon tactics an example of?
-if male is not the strongest, he comes up with another tactic to mate with the female
-conditional strategies can evolve if there is flexibility in the behavior
what is another example of conditional strategies being used in reproductive behaviors?
- Remove dominate male changes their strategies/tactics --> flexibility
a form of sexual selection that occurs when female mating preferences for certain male attributes create a positive feedback loop favoring both males with these attributes and females that prefer them
example of polymorphism: lizards
Orange - hold territory
Yellow - sneaky
Dash at unguarded female
Blue - monogamous
All energy in one female
Orange beat blue, blue beat yellow, yellow beats orange
Altruism! (kept in check by the other colors)
Females bring back colors
Female prefer rarer colors
polymorphism vs conditional strategy
polymorphism = genetically determined/frequency dependent selection
cond. strategy = environmentally determined
a behavior in which one partner prevents the other partner from participating in extra-pair copulations
-usually male follows the female around
benefit vs cost in mate guarding
-benefit = decreases the probability that the female will go off and mate again and use the sperm of another mate
-cost = lost opportunity to mate with other females
-if a behavior by a males reduces female fitness but provides the male with fitness
-cycle could start in which there is an increase in female resistance to male display
-two sexes battle for maximum genetic advantage even if one member of the pair loses
-"exploitative of preexisting sensory biases"
the evolution of phenotypic characteristics that confer a fitness benefit to one sex but a fitness cost to the other
-when males and females have different sexual motivations
OTHER SETS BY THIS CREATOR
Week 8-Lecture 1
Week 7-Lecture 2
Week 7-Lecture 1
THIS SET IS OFTEN IN FOLDERS WITH...
Chapter 1-Week 1(Lecture 1)
Ch. 2/3-Week 1(Lec. 2)
Ch. 4-(Week 2-Lec. 1)
Ch. 5-Week 2(Lec. 2)