Chapter 3 Flashcards
The Evolving Mind: Nature and Nurture Intertwined
adaptation
a change because of natural selection
alleles
one of several versions of a gene
altruism
behaviour on behalf of another that fails to benefit or harms the individual performing it
behavioural genetics
the scientific field that attempts to identify and understand links between genetics and behaviour
candidate gene
a gene that has a greater impact on a trait of interest than other genes
concordance rates
the statistical probability that a trait in one person will be shared by another
dominant
a feature of an allele that determines a phenotype in either the homozygous (dominant) or the heterozygous condition
epigenetic
the study of gene-environment interactions in the production of phenotypes
evolution
descent with modification from a common ancestor
fitness
the ability of one genotype to reproduce more successfully relative to other genotypes
gene
a small segment of DNA located in a particular place on a chromosome that produces a protein
gene expression
the process in which genetic instructions are converted into a feature of a living cell
genetic drift
a change in a population’s genes from one generation to the next because of chance or accident
genome-wide association studies (GWAS)
a scan of complete sets of DNA from many participants, which is performed to look for variations associated with a particular phenotype, condition, or disease
genotype
an individual’s profile of alleles
heritability
the statistical likelihood that variations observed in a population are because of genetics
heterozygous
having two different alleles for a gene
homozygous
having two of the same alleles for a gene
migration
movement to a new location
mutation
an error that occurs when DNA is replicated
natural selection
the process by which survival and reproductive pressures act to change the frequency of alleles in subsequent generations
nature
the contributions of heredity (genetic makeup) to our physical structure and behaviours
nurture
the contributions of environmental factors and experience to our physical structure and behaviours
phenotype
an observable characteristic
recessive
a feature of an allele that produces a phenotype only in the homozygous (recessive) condition
reciprocal altruism
help that you provide for another person when you expect the person to return the favour in the future
relatedness
the probability that two people share the same allele from a common ancestor
sexual selection
the development of traits that help an individual compete for mates
the first person to use the phrase “nature vs. nurture”; Darwin’s cousin
Francis Galton (1869)
the two types of cells that don’t contain two complete copies of the human genome
- red blood cells
- germ-line cells (sperm or eggs)
the number of chromosome pairs in a normal human
23 chromosomal pairs
the amount of combinations of chromsomes a single human’s eggs or sperm can produce
223 (8,388,608)
relatedness of families
- 0.50 with parents
- 0.50 with siblings
- 0.25 with nieces or nephews
amount of human chromosome pairs that are perfectly matched
22 pairs, excluding the X and Y chromosomes
intersex
individuals who are born with sex characteristics (genitals, gonads, chromosome patterns) that do not fit typical binary notions of male or female bodies
sex-linked characteristics
found only on the X or Y chromosome (e.g. hemophilia - the failure to clot blood - is found only on the X chromosome)
If genes are totally responsible for all phenotypical differences among individuals, heratibility is…
1.0
range of heritability for most human traits
0.30-0.60
Heritability refers to ___________, never ___________.
populations, individuals
If the environment is held constant, heritability is…
high
Researchers question the use of adoption studies for assessing the relative influences of genetics and environment on development due to…
the influence of the environment on heritability; adoptive parents rarely represent as much diversity as the group of biological parents whose children they adopt
Twin studies are useful in establishing…
concordance rates
Concordance rates are useful because…
they can provide estimates of the heritability of a psychological disorder
Humans share 100% of their _____, not _______.
genes, alleles
how genes encode for behaviours
they don’t, they encode for proteins
Different phenotypes can result from the same genotype due to…
interactions between the organism and its environment
Genes can be turned on/off by…
- internal signals (hormones, neurochemicals)
- external signals (diet, toxins)
the stage of life that experiences the highest rate of epigenetic change
fetus
factors known to produce epigenetic change
- nutrition
- disease-causing organisms
- drugs
- stress
- environmental toxins
four processes that produce lasting (but reversible) changes in gene expression
- RNA interference
- RNA editing
- histone modification
- DNA methylation
histones
protein structures around which your DNA is wound
the effect of histone modification
the expression of nearby segments of DNA can become more or less likely
DNA methylation
the addition of a methyl group to a DNA molecule
the effect of DNA methylation
genes turn off
three psychological disorders that hundreds of separate genes (or DNA methylation and unusual histone modifications) appear to be linked to
- schizophrenia
- autism spectrum disorder
- bipolar disorder
the combination of these two things provide scientists with powerful hypotheses about the progression of species over time
Mendelian genetics and Darwinian evolution
four evolutionary processes
- mutation
- migration
- genetic drift
- natural selection
number of mutations in an average human baby
about 130 new mutations
Natural selection favours the organism with the highest degree of…
fitness
this describes the interaction between characteristics and the environment in which they exist
fitness
forms of adaptations
behaviours or anatomical features
how adaptations are passed on
any adaptation that is good enough to contribute to the fitness of an organism will carry forward into future generations
Adaptations are compromises between…
costs and benefits
hominin
species that walk on two feet, have large brains, and are assumed to be related to modern humans
the evolution of brain size within hominins
- 400 cm3 in australopithecines
- 700 cm3 in Homo erectus
- 1,400 cm3 in Homo sapiens
Certain “hotspots” within the cerebral cortex act as…
communication hubs; they play a central role in supramodal cognition (the ability to integrate information from across the brain in a flexible, task-dependent manner)
four creatures with large brains and considerable intelligence
- hominins
- primates
- elephants
- whales
three ecological challenges faced by hominins
- finding food
- avoiding predators
- navigating through territories
the major factor distinguishing human intelligence from intelligence of other species
the richness and complexity of the social behaviour supported by the human brain
the leading factor to the evolution of the human brain
social complexity; the ability to:
- distinguishing friend and foe
- imitating the behaviour of others
- using language to communicate
- recognizing and anticipating the emotions, thoughts, and behaviours if others
- maintaing relationships
- cooperating with others
the evolutionary psychology perspective towards the evolution of behaviour
current behaviour exists because it provides some advantage in survival and reproduction
the psychological approach of which evolutionary psychology was descended
functionalism
two benefits of belonging to a social group
protection and assistance
two drawbacks to being social
competition for food and mates, and exposure to contagious illnesses
four types of social interactions
- cooperative: two individuals help one another
- selfish: one individual fends for self
- spiteful: both individuals lose
- altruistic: one individual self-sacrifices to benefit the other
why altruism proves evolution
Despite altruism resulting in the destruction of the individual, sacrifices to a close blood relative can lead to an increased likelihood that your alleles will be passed along to subsequent generations.
females’ investment in children
- bears the most costs of reproduction (i.e. carrying the fetus until burth, nurturing the baby until adulthood)
- faces sharper limitations on the number of children physically able to produce
- the children that are produced must be as healthy and well-nurtured as possible, due to the inability to produce many
- must choose a father who will pass along healthy genes, and also participate in the raising of children
males’ investment in children
- lower investment of time and resources in reproduction
- abandoning your offspring puts their survival at risk
- genes are less likely to be passed on, if children perish from lack of care or protection
the influence of testosterone-linked facial features on women
men with facial features correlated with high testosterone (i.e. strong brow ridge, square chin) are viewed as less likely to participate in childbearing, than men with facial features correlated with lower testosterone
the two ways in which sexual selection might occur
- intrasexual selection: members of one sex compete with one another for access to the other sex (e.g. male deer engage in fights to determine which males are allowed to mate)
- intersexual selection: characteristics of one sex that attract the other might become sexaully selected (e.g. a male peacock’s tail attracts mates)
two human traits that evolutionary psychologists believe might have been subjected to sexual selection
humour and vocabulary
a human trait that does not attract females
taking unnecessary risks
culture
socially transmitted knowledge, practices, values, and goals that are shared by groups of people
what might have been the origin of patriarchal systems, in which men maintained control of resources and inheritances follow the male line
agriculture
