psych 304: exam 1 Flashcards
evolutionary psychology’s four key questions
◦ why is the mind designed the way it is? what causal processes created, fashioned, or shaped the human mind into its current form?
◦ how is the human mind designed? what are its mechanisms or component parts, and how are they organized?
◦ what are the functions of the component parts and their organized structure? what is the mind designed to do?
◦ how does input from the current environment interact with the design f the human mind to produce observable behavior?
evolution: definition
change over time, gradual change in species
who was jean-baptiste lamarck?
first evolutionist to speak of evolution and assumed species adapt to their environment
lamarck’s theory of evolution
◦ believed in two major causes of species change: natural tendency for each species to progress toward a higher form and the inheritance of acquired characteristics
◦ animals must struggle to survive and this struggle causes their nerves to secrete a fluid that enlarges the organs involved in the struggle (e.g., giraffes evolved long necks through their attempts to eat from higher and higher leaves)
◦ neck changes that came about from these strivings were passed down to succeeding generations of giraffes = inheritance of acquired characteristics (soft inheritance)
◦ was put to a final end by Weismann barrier, the principle that hereditary information moves only from genes to somatic cells, never in reverse
catastrophism
◦ Baron Georges Leopold Chretien Frederick Dagobert Cuvier
◦ species are extinguished periodically by sudden catastrophes and then replaced by different species
who was charles darwin?
first to explain how change might take place over time
darwin’s travels
◦ traveled from 1831 to 1836, where he collected samples of birds and other animals from Galapagos Islands
◦ found that different finches had a common ancestor but had become different from each other because of the ecological conditions on each island
how did darwin get to his theory?
◦ unearthed key to the puzzle of adaptations in Thomas Malthus’s An Essay on the Principle of Population (1798), which introduced Darwin to the notion that organisms exist in numbers far greater than can survive and reproduce
◦ the result must be a “struggle for existence”
◦ he eventually came up with the theory of natural selection
theory of natural selection: three ingredients
principle of variation, principle of inheritance, principle of selection
principle of variation
◦ individuals in a population have variation in their physical and behavioral traits (i.e., phenotype)
◦ organisms vary in all sorts of ways
◦ variation provides raw materials for evolution
principle of selection
◦ selection pressure: any phenomena which alters the behavior and fitness of living organisms within a given environment
◦ organisms with heritable variants leave more offspring because those attributes help with the tasks of survival or reproduction
principle of inheritance
◦ principle of inheritance: some of this variation is heritable (i.e., due to genotype)
◦ only some of these variations are inherited, these are the ones that play a role in the evolutionary processt
theory of sexual selection
◦ focused on adaptations that arose as a consequence of successful mating
◦ intrasexual competition: competition between members of one sex, the outcomes of which contributed to mating access to the other sex
◦ intrasexual selection or preferential mate choice: those with desired qualities will be chosen as mates; evolutionary change occurs because the qualities desired in a mate increase in frequency with the passing of each generation
the role of natural selection and sexual selection in evolutionary theory
◦ natural and sexual selection are not the only causes of evolutionary change
◦ evolution by natural selection is not forward looking and is not intentional
◦ selection is gradual
genetic drift
◦ random changes in the genetic makeup of a population, can occur through mutation, founder effects, and genetic bottlenecks
◦ happens to all populations, has drastic effect in small populations, driven by chance not selection
founder effect
◦ small portion of a population establishes a new colony and the founders of the new colony are not genetically representative of the original population
◦ other definition: reduction in genetic variation that happens wehn a small group of individual starts a new population
genetic bottleneck
◦ reduction in genetic variation that happens due to a dramatic reduction in population size (population crash), changes gene pool
mutation
◦ copying error in a piece of DNA
◦ changes in DNA
◦ external influences: exposure to specific chemicals, radiation
◦ are random
Gregor Mandel’s peas
◦ studied inheritance of 7 different features in pea plants
◦ demonstrated that genes are the units of heredity
◦ inheritance is particulate (passed on intact to their offspring in genes), not blended
genotypes
◦ entire collection of genes within an individual/set of genes an organism carries (bb)
phenotypes
◦ set of observable characteristics, based on genotypes and environment (blue eyes)
tinbergen’s four “why’s” of behavior”
◦ immediate influences on behavior [proximate: how]
‣ what is cause of behavior?
◦ developmental influences on behavior [proximate: how]
‣ how the behavior develops?
◦ function of behavior, or adaptive purpose it fulfills [ultimate: why]
‣ what is the function of the behavior?
◦ evolutionary or phylogenetic origins of behavior [ultimate: why]
‣ why did the behavior evolve as it did?
proximate (how)
◦ how did environment and the individual’s genetic makeup interact to produce the behavior?
◦ what body systems (nervous, hormonal, etc) are involved in this behavior?
ultimate (why)
‣ what is the function?
‣ how does/did this trait help individuals increase their genetic representation in future generations?
‣ what environmental pressures selected for this trait?
‣ how has this behavior changed over evolutionary history?
inclusive fitness theory
◦ inclusive fitness: ability of an individual organism to pass on its genes to the next generation, taking into account the shared genes passed on by the organism’s close relatives
◦ inclusive fitness can be viewed as the sum of an individual’s own reproductive success, plus the effects their actions have on the reproductive success of their genetic relatives
William D. Hamilton
◦ created inclusive fitness theory
◦ classical fitness: passing on genes through the production of offspring
‣ Hamilton believed this was too narrow
◦ he theorized that natural selection favors characteristics that cause an organism’s genes to be passed on, regardless of whether the organism produces offspring directly
products of evolution by natural selection
adaptations, by products, random effects/noise
adaptations
◦ inherited and reliably developing characteristics that came into existence through natural selection
◦ they helped to solve problems of survival or reproduction better than alternative designs existing in the population during the period of their evolution
◦ must be genetic “for” an adaptation
◦ natural selection cannot act on traits that don’t get sent to offspring
◦ example: umbilical cord
adaptations (simpler definition)
◦ evolved solutions to specific problems that contribute either directly or indirectly to successful reproduction
by products
◦ characteristics that do not solve adaptive problems and do not have functional design
◦ they are carried along with characteristics that do have functional design because they happened to be coupled with those adaptations
◦ belly button
noise
◦ random effects produced by forces such as chance mutations, sudden and unprecedented changes in the environment, or chance effects during development
◦ not linked to the adaptive aspects but it’s independent of these features
◦ some are beneficial
◦ variation in belly-button shape/type
primary product of evolution by selection
adaptations
adaptations criteria
‣ reliability: does the mechanism regularly develop in most or all members of the species across all “normal” environments and perform dependably in the contexts in which it is designed to function?
‣ efficiency: does the mechanism solve a particular adaptive problem well and effectively?
‣ economy: does the mechanism solve the adaptive problem without extorting huge costs from the organism?
