Evolution, natural selection and aggression Flashcards
What is the advantage of the evolutionary theory of aggression?
- A strength of the evolutionary theory is that it can explain why males are more aggressive than females
- Females who are cooperative are likely to be naturally selected because cooperation helps them protect themselves and their offspring as a group
- Therefore reduced aggression is selected in females
- In contrast males who are aggressive are more likely to be naturally selected because they make better hunters and protectors
- Evidence from the chimpanzee study supports this pattern of gender differences
- This is a strength because it explains gender differences in aggression today increasing the validity of the theory
Define gene
A gene contains a set of instructions and is a carrier of information
Define phenotype
Our phenotype is what we become when our genes interact, both with one another and with our environment and experiences
Describe how genes control the characteristics of a human
- Dominant genes lead to certain characteristics, they need to be on only one of a pair of chromosomes to be shown
- Some genes are recessive which means they have to be on both chromosomes of a pair for the characteristic to occur otherwise it will not be presented in an organism
- Recessive genes can be passed on so the characteristic might appear in a future generation
Define Evolution
Evolution is how inherited characteristics in organisms change from generation to generation
Define natural selection
Refers to how some characteristics are inherited because they aid the survival of an organism so that there can be reproduction and passing on of genes, whereas some characteristics that don’t aid survival in the environment are not reproduced
Describe Darwin’s natural selection theory
- Darwin suggests that organisms have more offspring than are required, some characteristics aid survival, and some characteristics are inherited
- He suggests that those characteristics that aided the survival of the organism allowing it to reproduce its genes, are bound to be the characteristics for survival
- Any characteristic that did not help survival would die out because that organism with that characteristic would not survive to reproduce, if the organism doesn’t reproduce those genes die out
- Natural selection only works if there is sufficient variation in the species for certain genes to lead to characteristics that help the organism to survive
Define survival of the fittest
Refers to how organisms that suit their environment will survive long enough to reproduce so that their genes will continue
Describe Darwin’s survival of the fittest theory
- Survival of the fittest is how organisms adapt, only inherited characteristics that help with survival so that reproduction can take place are passed on in genes because it is only through reproduction that genes are passed on
- There could be genetic mutations that can change genes in a species as well as random chance in genes that are passed on which is called genetic drift
- Survival of the fittest is affected by genetic mutation as not only will those with the original genes survive if their characteristics suit their environment, but also those with advantageous mutations too
Define sexual selection
Sexual selection is an evolutionary explanation of partner preference, attributes, or behaviors that increase reproductive successes are passed on and may become exaggerated over succeeding generations of offsprings
Describe guarding your partner as an evolutionary characteristic
- Mate retention strategies are the often aggressive behaviors men use to retain partners and prevent them from infidelity
- Bus and Shackleton gathered evidence to see what men do in response to feeling threatened in a relationship and to see if the evidence is there for the idea of natural selection, the researchers found men tended to give in to the female giving everything she wanted and they were threatening any other males around
- Both strategies would aid the survival of the male’s genes
- For women too, it is helpful for the survival of their genes if they maintain a relationship to reproduce, however according to Bus and Shackleton women tend to threaten to leave the man if he is unfaithful and also uses verbal threats to other females
Describe the application of the evolution theory of aggression
- Evolutionary theory can help us understand human relationships as it predicts that we should choose partners who will enhance our reproductive success
- David Buss found that across 33 countries, males preferred younger, more attractive women because this enhances their reproductive successes because such women are more likely to be fertile
- Females preferred older, wealthier and ambitious men which is likely to enhance their reproductive success because their children are well supported
- This supports the evolutionary theory because it shows that the productions from the theory are upheld by evidence
Describe the disadvantages of the evolutionary theory
- A weakness in the evolutionary theory is that there are differences between cultures in aggressive behaviour
- Amongst the people of the Kalahari aggression is discouraged from childhood and is therefore rare
- In contrast, the people of Venezuela and Brazil has been described as fierce people - aggression seems to be an accepted behavior to gain status in their structured society
- These differences in aggression are not universal and suggest that innately determined behavior can be outweighed by social norms
Describe guarding your offspring as an evolutionary characteristic
- Human parents will direct aggressive acts against other people that threaten their children, this aggression is adaptive because each child is a valuable genetic commodity
- Eric Steiner points out that protecting offspring is one of the very few situations in which females behave just as aggressively as males
What do the effects of nature on behavior mean
This means the influence of genes and other biological structures
