evolution, natural selection and aggression Flashcards
what is evolution ?
the changes in inherited characteristics in a biological population
when does natural selection happen ?
when there is competition for scarce resources
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 a succeeding generations of offspring
what does sexual selection explain ?
why some characteristics might appear disadvantageous actually confer a survival advantage because the characteristics are attractive to potential mates
what is an example of sexual selection ?
a male peacock’s tail appears to have a huge handicap that threatens his life - it is difficult to manoeuvre and is heavy. The advantage is that female peacocks find them attractive as they see it as a sign of genetic fitness
how are evolution and aggression connected ?
in humans, being able to protect yourself and your possessions (partner and offspring) would all enhance survival and reproduction - so it would have been modified by natural selection
what is meant by guarding your partner ?
mate retention strategies are often aggressive behaviours to make sure they retain their partners and prevent them from ‘straying’ - according to Margo Wilson and Martin Daly (1996) direct guarding involves males being vigilant over their partner’s behaviour
what is meant by guarding your offspring ?
parents will direct aggressive acts against other other people or animals that threaten their children. the aggression is adaptive because each child is a valuable genetic commodity - a way of protecting their ‘investment’ - Eric Steiner (2016) points out that when it comes to protecting offspring, it is one of the only times that females are just as aggressive as males
(evaluation) what is a strength of the theory?
- explains why males are more aggressive than females
- females who are naturally cooperative are likely to be naturally elected because cooperation helps them protect themselves and their offspring as a group - reduced aggression is selected in females
- men who are more aggressive are more likely to be chosen because they are better hunters
- Manson and wrangham (1991) saw this from studies of chimpanzees
- explains gender differences in humans today and increases validity
(evaluation) what is a competing argument to the strength ?
- any evolutionary explanation is uncertain because it is impossible to test evolution directly - why most research is correlational (e.g., finding associations between mate retention behaviours and aggression.)
- this method does not allow cause-and-effect conclusions
(evaluation) what is a weakness of the theory ?
- differences between cultures in aggressive behaviours
- !kung san people of the Kalahari discourage aggression from childhood and is rare
- yanomami of Venezuela and Brazil have been described as ‘fierce people’ - aggression gains status
- differences in aggression are not universal, suggests innately human behaviours can be controlled by social norms
(evaluation) what is a application of the theory ?
- helps us understand human relationships as it predicts that we should choose partners on who will enhance our reproductive success
- David Buss (1989) - across 33 countries, males preferred younger, more attractive, chaste women. females preferred older, wealthier and ambitious or hard-working men
what did Eric Steiner (2016) find ?
Eric Steiner (2016) points out that when it comes to protecting offspring, it is one of the only times that females are just as aggressive as males
what did Manson and wrangham (1991) find ?
they found that male chimpanzees were more likely to be picked if they were more aggressive and female chimpanzees were more likely to be picked as a mate if they were agreeable and cooperative
what did David Buss (1989) do and find ?
David Buss (1989) - across 33 countries, males preferred younger, more attractive, chaste women. females preferred older, wealthier and ambitious or hard-working men
