define evolution
each thing has a set of characteristics which is encoded by genes, the offspring receives this during reproduction
therefore the variation between organisms is the difference in genotypes
3 main steps in evolution
to live to reproductive age
to mate successfully
to ensure offspring survival
whats natural selection
the ability to survive in a specific environment
whats sexual selection
the ability to attract and reproduce, the attributes and behaviours that inc reproductivity are passed onto future generations
whats anisogamy
Anisogamy refers to the differences between male and female sex cells (gametes).
Male gametes (sperm) are small, mobile, and produced continuously in large quantities throughout a man’s reproductive life. This makes them “cheap” from a biological perspective.
Female gametes (eggs), however, are larger, static, and produced in limited numbers—typically one per menstrual cycle, and only during a limited reproductive window in her life. This makes them “expensive” in terms of energy and biological investment.
whats inter sexual selection and whats the female preference
Inter-sexual selection refers to the process where one sex (usually females) selects mates from the opposite sex based on desirable traits. This is often called the female choice strategy.
Because females invest more biologically in reproduction (e.g. pregnancy, limited number of eggs, child-rearing), they tend to be more selective.
They typically look for males with traits that indicate good genes, the ability to provide resources, or strong protection—this increases the chances of survival for their offspring.
what is the male preference within inter sexual selection
reproductive success, they aim to reproduce a lot and usually go for a large hip to waist ratio which reflects ability to reproduce
whats the impact of inter sexual selection
females become more choosy as they want the best for their offspring ( sexy sons hypothesis )
whats intra sexual selection
Intra-sexual selection refers to the competition between members of the same sex (usually males) for access to mates. This is often called the male competition strategy.
Because males produce many sperm and can father many offspring with little biological investment, they benefit from competing for access to as many fertile females as possible.
what do males go for within intra sexual selection
quantity, they want to compete for female access as sperm is plentiful “ the winners “ pass on traits
whats the impact of intra sexual selection
dimorphism, males have exaggerated characteristics to become attractive however a weakness of this is that it also attracts predators
strength of evolutionary explanation
review of lonley hearts study found males go for young women and females go for professional and wealthy
supports as it reflects sex-specific mate preferences predicted by evolutionary theory:
strength 2 of evolutionary explanation
a study was completed where students were i asked ‘ i find you attractive, would you go to bed w me’
0% women
75% males
supports f is choosy and males are more willing to engage in casual sex, which fits with the male strategy of maximising reproductive success.
weakness of evolutionary explanation
buss claims sexual selection theory is too simplistic as it states different strategies used for different sexes
buss suggests the same strategy is used when looking for long term partners
SUGGESTS OVER SIMPLISTIC AND PROPOSES A MORE COMPLEX THEORY WHICH CONSIDERS CONTEXT
weakness 2 of evolutionary theory
partner preferences have been influenced by changing social norms and culture
eg: contraception, changing workplace roles
partner preference no longer resource orientated
EE DOESN’T CONSIDER CULTURE BOTH, limited
define physical attraction
assumes we seek to form relationships with most attractive
whats the evolutionary explanation within physical attractiveness
attraction is result of sexual evolution, using attractions as a symbol of genetic fitness
what was the study of evolutionary explanation within physical attractiveness
Shackleford: found people w symmetrical faces attractive. Baby face features eg: big eyes, small nose to represent caring feauture
strength of evolutionary explanation within physical attractiveness
research support
found women w big eyes and large nose were rated as attracted across white, asian and hispanic
features consistent across cultures
whats the halo effect within physical attractiveness
people who are seen as attractive are seen in a positive light
Dion found people who were kind sociable and successful were attractive when compared to others
strength of halo effect
research support.
found attractive politically education and competent.
supports theory but raises the question of if we chose politics based of suitability or attractiveness
whats the matching hypothesis
we look for partners that are on a similar level of attractiveness to what we think of ourselves
strength of matching
feingold research support
meta analysed 17 studies of rl couples and found correlation between partners attractiveness, supports
weakness of matching hypothesis
In Walster’s “Computer Dance” study, students were paired randomly by a computer and secretly judged by a panel on attractiveness.
during intervals and 4-6m later partners were asked if they wanted a second date and if they found partner attractive.
found higher appreciation of partners than themselves