evolutionary explanations Flashcards
what is sexual selection?
an evolutionary explanation of partner preference. Attributes or behaviours that increase reproductive success are passed on and may become exaggerated over succeeding generations of offspring
what is anisogamy?
differences between male and female sex cells (sperm and ova) which give rise to different mating strategies.
it gives rise to the two types of sexual selection
what is inter- sexual selection?
it’s between (inter) the sexes. the strategies males or females use to select eachother. it it the preferred mating strategy for females, ‘quality over quantity’ and have high standards of a partner
what did Trivers point out?
that females make a greater investment of time and commitment so need to choose a reliable partner. the females optimum mating strategy is to select a genetically fit partner who is able to provide resources.
what is the ‘sexy sons hypothesis’?
that females preference for a genetically ‘fit’ male ensures that desirable characteristics are inherited by male offspring- the genes that we see today are those that enhanced reproductive success
what is intra- sexual selection?
it’s within (intra) each sex- such as the strategies between males to be the one that is selected. it is the preferred strategy of the male, quantity over quality. males compete to mate with as many females as possible.
what is dimorphism?
•‘two forms’
•males and females end up looking very different because of intra- sexual selection
example of dimorphism
•in males, larger males have an advantage and are more likely to reproduce
•in females, youthfulness is selected because males have a preference to mate with younger, more fertile women
what is sneak copulation?
sex
what is sperm competition?
bigger balls means more sperm, more likely to reproduce, influences promiscuity- more likely to be established as the alpha male
what are the two hypotheses in inter-sexual selection?
•’good taste’ (females choose a man based on how attractive and how big they are)
•’good sense’ (how the male still survives despite despite the bigness of said characteristic- handicap principle)
•females are attracted to males who carry a burden and still survive
what are the two hypotheses in inter-sexual selection?
•’good taste’ (females choose a man based on how attractive and how big they are)
•’good sense’ (how the male still survives despite despite the bigness of said characteristic- handicap principle)
•females are attracted to males who carry a burden and still survive
strength: research support for inter-sexual selection
•Clark and Hatfield sent male and female psychology students out across a university campus to approach other students and ask if they’d sleep with them tonight
•no females said yes, but 75% of males did
•this supports the view that females are ‘choosier’ than males when it comes to selecting sexual partners
limitation: saying that one sexual selection strategy is true for all males and one for all females is simplistic
•Buss and Schmitt argued that both males and females adopt similar mating strategies when seeking long- term relationships.
•both sexes are very choosy and look for partners who are loving, loyal and kind
•this is a more complex view of how evolutionary pressures influence partner preferences which takes account of the context of reproductive behaviour
strength:research support for intra-sexual selection
•Buss carried out a survey and found that females placed a greater value on resource-related characteristics than males did, such as good financial prospects and ambition
•males valued physical attractiveness and youth (as signs of good reproductive capacity) more than females did
•these findings reflect consistent sex differences in partner preferences and support the predictions from sexual selection theory
limitation: social and cultural influences underestimated
•partner preferences over the past century have undoubtedly been influenced by rapidly changing social norms of behaviour
•womens greater role in the workplace means they are no longer dependent on men to provide for them
•this social change has consequences for women’s mate preferences, which may no longer be resource- oriented
•likely to be a combination of evolutionary and cultural factors
