PSYCH 1XX3 - Evolution

adaptation

biological traits that help an individual to survive and reproduce in its habitat - adaptations perform a specific function

what are the four major mechanisms to evolution?

natural selection, mutation, genetic drift, migration

natural selection

differential survival and reproduction of organisms as a result of the heritable differences between them

what are the three essential components of natural selection?

individual differences, differential reproduction, heritability

individual differences

within any population there is variation among individuals for any given characteristics

differential reproduction

differences between individuals affect their ability to survive and reproduce

heritability

offspring of these reproducers will resemble their parents with respect to these variable characteristics

stabilizing selection

selection against any sort of departure from the species typical adaptive design

evolution

change in gene frequencies over generations, in part due to the introduction of new gene variations via mutations

sexual selection

the component of natural selection that acts on traits that influence an organism's ability to obtain a mate, resulting in differential reproductive success

Darwinian Fitness

average reproductive success of a genotype relative to other genotypes

intersexual selection

competition within individuals to capture the interest of the opposite sex (i.e. peacocks)

intrasexual selection

competition within individuals for access to the opposite sex (i.e. elks)

how can you tell if a trait is sexually selective?

if traits differ between sexes or if a trait is exaggerated during breeding season

behavioural genetic studies

selectively breeding in/out different traits, these studies favour animals with short lifespans (i.e. drosophila - fruit flies)

cooperation

positive effect on actor's and recipient's well being

what effects does altruism have?

positive effect on recipient's well being and negative effect on actor's well being

selfish

negative effect on recipient's well being and positive effect on actor's well being

spite

negative effect on actor's and recipient's well being

what are the benefits to foraging?

reduces trade off (animals having to watch for predators while foraging), group as a whole is more vigilant than an individual, foraging in groups can increase personal success in finding food and watching for predators

altruism

behaviour in which the actor incurs a cost to provide a benefit to a recipient - altruism reduces an individual's fitness

what is NOT an example of altruism?

foraging (an example of cooperation)

eusocial hymenoptera

in this level of social organization, most individuals spend their lives serving the colony without reproducing

direct fitness

fitness from personal reproduction

indirect fitness

fitness from the reproduction of close genetic relatives - you can increase your own fitness by helping kin

Hamilton's Rule

predicts when altruistic behaviour is favoured

r

relatedness

B

reproductive benefit to recipients

C

reproductive cost to actor

relatedness

probability that actor and recipient share gene in question

what percentage of homicide cases are done by genetic relatives

6%

cues of kinship

mother's association and co-residence with other children

why are female ground squirrels more likely to give alarm calls

female ground squirrels stay in natal territory for life while males leave; more willing to be altruistic to kin

phenotypic matching

evaluation of relatedness between individuals based on an assessment of phenotypic similarity

direct reciprocity

two people help each other and both benefit

indirect reciprocity

helping others to get more help later on due to developing a good reputation

what do females peacocks (peahens!) prefer in males

males with tails that have more eyespots and symmetry

mate choice preference

females choice picks out males with best resistance to diseases

prisoner's dilemma

situation showing that cooperation is difficult to maintain, if both confess they have to do 5 years, if one confesses they go free while the other stays in prison for 20 years, if neither confesses they stay in prison for 1 year

which grandparent has the best relationship with their grandchildren?

maternal grandmother

which grandparent has the worst relationship with their grandchildren

paternal grandfather

why do maternal grandmother's have the best relationship with their grandchildren?

she has parental certainty, there is no doubt that you are her grandchild

why do paternal grandfather's have the worst relationship with their grandchildren?

they don't have parental certainty - they can't guarantee their own son is their child let alone their grandchild

what qualities do women look for in men?

possession of resources, access to resources, commitment

what qualities do men look for in women?

youth, health, attractiveness

sexual overperception bias

men see more potential for romantic relationships, men over infer sexual interest due to a great cost to losing out on a potential partner

which sex has high variance?

male - motivates them to try to stand out to women

which sex has low variance

female

who demonstrates more risk taking behaviour and why?

men, more comfortable taking risks for rewards than women due to different historical needs

evolutionary psychology

pursuit of psychological science with explicit attention to contemporary knowledge and theory about the evolutionary process

why are women for discriminating in mate choice than men?

bad choices in mates are more costly to females because their are more invested in their offspring than males

phylogeny

pattern of evolutionary development and divergence of distinct evolving lineages from common ancestors

adaptive radiation

diversification of a group of organisms into different forms fulfilling different ecological niches

mate choice

component of intersexual selection where a mate is chosen based on the attractiveness of a trait

fluctuating asymmetry

measure of bilateral traits that are symmetrical over the population as a whole, but not necessarily as an individual; higher symmetry = more desirable

waist-to-hip ratio

circumference of waist divided by circumference of hips - women with lower waist-to-hip ratios have more estrogen and are more fertile than women with higher waist-to-hip ratios

sexual jealousy

feelings of anger and desire to guard a mate or sexual prospect from engaging in sexual activity from potential rivals

romantic jealousy

feelings of anger and a desire to guard a mate or sexual prospect from leaving the relationship to form a new one with potential rivals

who is sexual jealousy more common in?

men

who is romantic jealousy more common in?

women

social behaviour

actions directed at society or taking place between members of the same species

positively related (genetic relatedness)

more related than we would expect by chance alone (r > 0)

negatively related (genetic relatedness)

less related than we would expect by chance alone (r < 0)

eugenics

practice that promotes the selection of desired traits through constraints on reproduction, and even elimination of individuals with undesirable genes

kin recognition

psychological mechanism that helps an organism distinguish between non-kin and genetically related kin

maternal-perinatal association

older siblings learn to recognize other offspring their mother cares for as younger siblings

co-residence duration

the longer two individuals have lived together throughout childhood the more likely they are to be related

incest aversions

aversion to mating with close relatives

inbreeding

reproducing among close relatives, especially across generations

kibbutzim

communities in Israel where children are raised together regardless of being siblings. when children grow older and realize they aren't related to each other they still usually never marry someone from the same kibbutz due to the co-residence kinship cue.

phenotypic similarity

observable characteristics, both behavioural and physical, that result from the interaction of an individual's genotype with its environment

parent-offspring conflict

conflict that arises from differences in the optimal parental investment from the point of view of the parents and the offspring

diminishing marginal gains

decline in the gain a person derives from the consumption of each additional unit of a product

evolutionary arms rate

a mutation in a gene expressed in offspring that helps the youngster extract more maternal resource than is optimal for mom may increase rapidly in prevalence