Chapter Eight Flashcards
natural selection
results in the gradual changes in a species over time, as successful variants increase in frequency and eventually spread throughout the gene pool, replacing the less successful variants
sexual selection
- the evolution of characteristics based on their mating benefits
- two kinds intrasexual vs intersexual competition
intrasexual competition
competition between same sex individuals for mates, resources, etc.
intersexual selection
members of one sex choosing a mate based on their preferences for particular qualities
differential gene reproduction
defined by reproductive success relative to others
inclusive fitness theory
- the “inclusive” part refers to the fact that the characteristics that facilitate reproduction need not affect the personal production of offspring
- they can affect the survival and reproduction of genetic relatives as well
adaptations
reliably developing structure in the organism which causes the solution to an adaptive problem
byproducts of adaptation
things created by the evolutionary process that are not adaptations
(lightbulbs designed to produce light which is its function but it also produces heat as an incidental by product)
evolutionary noise
random variants that are neutral with respect to selection
(ie. the design of a lightbulb, there are minor variations in the surface texture of the bulb that do not affect the functioning of the design elements)
basic human motivation proposed to have evolved to prevent us from being excluded
- according to hogan, being ostracized from a group would have been extremely damaging
- therefore, it can be predicted that humans have evolved psychological mechanisms to prevent being excluded
evidence indicating that the need to belong is a central motive for humans
- baumeister and leary argue that the group serves several key adaptive functions for individuals:
- share food, information, and other resources
- offer protection from external threat or defence from rival groups
- contain concentrations of mates, needed for reproduction
- contain kin, which provide opportunities to receive altruism and invest in genetic relatives
genetics and altruism
- burnstein and colleagues hypothesized that helping others is a direct function of the recipients’ ability to enhance the inclusive fitness of the helpers
evidence of genetics and altruism
- studies in the US and japan support predictions
- participants asked to imagine different individuals sleeping in different rooms of a burning house; tendency to help is a direct function of the degree of relatedness
age and altruism
burnstein and colleagues predicted that people should help younger relatives more than older relatives because helping older kin would have less impact, on average, on their reproductive success than would helping a younger person
research on age and altruism
- studies on famine and disease, relationship between age and helping support this
- participants asked to imagine themselves in a sub-saharan african country that suffered from famine, infants were helped less, 10 year olds helped more then after 75 years old helped less