Chapter 3 - Genetics & Evolution Flashcards
Nature
The effect of our genes on our psychological traits and behaviors
Nurture
The effect of experience on our psychological traits and behaviors
Do genes directly produce thoughts, feelings and behaviors
No, they build, maintain and modify the physical structure of the body
Can different versions of genes be associated with psychological traits or behaviors
Yes they can
When are thoughts, feelings and behaviors generated
When the person interacts with the environment
Chromosomes
contain DNA and are situated in the cell of the nucleus
How many chromosomes are in each human cell
46 - 23 matching pairs
Female chromosomes
XX
Male chromosomes
XY
Coding Genes
contain the instructions for the creation of proteins
Genome
- an organism’s entire collection of genes
- set of instructions for making the organism
T or F - most DNA does code for proteins
False
Regulatory genes
activate or suppress other genes
Does a gene affect an organism if it is turned off?
expressed
No. When a gene is turned on is only when the cells starts producing the protein encoded by the gene
What can turn off gene expressions?
the environment or other genes
Genotype
the set of genes that an individual inherits
Phenotype
Observable properties of the body and behavioral traits
Genes are the biological basis of ?
Heredity
Heredity
the passing of traits to offspring from parents or ancestors
What contributes to human differences
Heredity and environment
Mitosis
When cells (other than reproductive cells) divide to create identical cells
Mitosis chromosomes
Each chromosome is duplicated exactly and the cell splits into two identical
Meiosis
reproductive cells replicate and divide many times to create non-identical cells
- cells splits into 4 cells. each w/ only 1 chromosome from each pair
Meiosis chromosomes
are duplicated and DNA is shuffled between the copies
Alleles
mutations of genes
- even a small genetic difference can lead to differences in physiology and behavior
Genes have a better chance of survival if
they are rearranged at each generation
Different genes can occupy the same focus and thus can potentially pair with each other
alleles
Homozygous
when two genes at the same location on a pair of chromosomes are the same
Heterozygous
when the two genes are not the same
Dominant allele
is one that will produce its observable effects (affect the phenotype) in either the homozygous or heterozygous condition
(only need one copy for it to have an effect)
Recessive allele
is one that will only produce its observable effects in the homozygous condition (need two copies to have an effect)
Mendel proposed
that genes comes in pairs (one from each parent) and that one can be dominant over the other
Can behaviors be affected by a single gene?
yes! e.g. fearfulness in dogs: comes from a single dominant gene
Polygenic characteristics
characteristics that are influenced by many genes. thee often vary continuously and have a normal distribution
Why is establishing the effect of genes very difficult?
- experiments are required to establish causation
- is isn’t practical to manipulate human genes
- you would also need to control the environment
Ideals when establishing the effect of genes
- a set of cloned individuals (identical twins)
- the ability to selectively alter genes prior to embryonic development
- complete control of the individuals environment throughout their lifespan
Identical twins
come from the same egg & same gender
fraternal twins
two eggs and can be different or same gender
in what ways are identical twins more alike than fraternal twins?
- personally traits (e.g. extroversion)
- sociability
- neuroticism (emotional instability)
- temperament (emotional excitability)
- behaviors/outcomes such as rate of divorce
- abilities such as overall intelligence
T or F - Fraternal twins have more similarities even when raised separately
False
Identical twins raised apart are still similar in what ways
- personality, styles of thinking and relating
- abilities/intelligence
- interests, tastes
- specific fears
- brain waves, heart rate
Epigenetics
gene-regulating activity that doesn’t involve changes to the DNA code and can persist throughout one or more generations
example of epigenetics
DNA methylation - are not expressed (shut off)
Do epigenetic effects make understanding the effects of genes easier?
no more challenging
Selective breeding
modifying a specific behavior or characteristic by mating individuals with or without the specific characteristics (AKA artificial selection)
Example of selective breeding
domestication of wolves into dogs
selected the most friendly wolves and fed and bred them.
- each gen became less aggressive and more social
When is evolution easiest to see?
In species with short reproductive cycles and facing changing selection pressures
given what we know about genetic inheritance ____________
evolution is inevitable
Is the origin of species by means of natural selection a valid theory?
it is a very successful theory. it is the only theory that has been able to provide an explanation for the available data regarding evolution
Natural selection
an evolutionary process through which adaptive traits are passed on to ongoing generations because these traits help animals survive and reproduce
Darwin’s essential point in natural selection
individuals of a species vary in their chance of survival and the number of offspring they produce
core concepts of the theory of natural selection
- overproduction of offspring in each generation
- variation in features or traits within each generation
- individuals differences are inherited from one generation to the next
- individual w/ collections of traits that fit well in the local environment are more apt to survive
what are the two sources of the genetic variability on which natural selection
- reshuffling of genes during reproduction
- mutations
natural selection misconceptions
evolution is not goal driven. Organisms survive and reproduce
Does evolution generate optimal designs?
no, they are designed by their ancestral environment not their current
are humans the most evolved?
no! evolutionary paths are not working towards some predetermined at the end
Are all traits from natural selection are to serve a beneficial purpose?
No, some are a result from chance
- used to be useful but not anymore
- some are side effects of other traits
Ultimate (Distal) explanations
functional explanations at the evolutionary level
Proximate explanations
explanations that deal with the mechanism in the immediate conditions
Does learning play any role in the development of species-typical behaviors?
Yes, it plays a crucial role.
- they engage in behaviors that promote learning
species-typical
every species has a certain characteristic ways of behaving
- they are products of evolution
examples of species-typical behaviors & learning
walking and language acquisition in humans
cross-species comparisons
comparing the ultimate causes of behavior with other animals to learn more about ourselves
Homologies
similarities due to common ancestry
why are homologies useful?
For studying underlying mechanisms and for tracing the evolution of species-typical behavior
examples of homologies
basic mechanisms : learning and sensation.
-we can be similar to other mammals
Analogies
similarities due to convergent evolution (independent evolution of similar traits)
why are analogies useful?
useful for inferring distal functions
Homologies - smiling (humans)
people smile in two different ways:
- when happy
- when wishing to show another person they are favorably disposed (greeting)
Homologies - smiling (nonhuman primates)
- one laugh that is used during play
2. one that resembles a human greeting smile (used to reduce chance of being a target of aggression)
Polygyny
one male + multiple females
- males are larger in order to compete
- e.g. elephant seals: only strongest ones mate
polyandry
one female + multiple males
- females are larger and more aggressive
- females court males
- e.g some birds species
Monogamy
one male + one female
-both gender compete for mates
-
Promiscuity
multiple mating partners within a group
- reduces competition and conflict w/n a group
e. g. chimpanzees
parental investment
time, energy and risk to survival involved in producing,feeding and caring for offspring
Promiscuity - parental confusion among males results in
- reduced aggression towards children
- increased likelihood that paternal investment in all children
Human mating patterns (females)
females invest more in child rearing
Human mating patterns (males)
males typically do invest in their children.
less polygamous
Polls : casual sex
male 58% and females 34%
Polls: sex for affection
males 25% and females 48%
Polls: think about sex everyday
males 54% and females 19%
Mens mating preference
number of offspring can be increased by having multiple partners
-quantity over quality strategy
Females mating preference
Multiple partners do not increase the number of offspring.
- it may reduce the amount of support provided by their mate
Men dating preferences
men place relatively more emphasis on physical features
Female dating preferences
women seeks partners that are loyal, mature, affluent and have social power
Love
tends to create mating bonds
jealousy
tends to preserve such bonds by motivating individuals to act in ways to prevent their partner from having an affair with someone else
Men’s jealousy
towards sexual infidelity
Women’s jealousy
towards their partner falling in love with someone else
Evolution of helping
promoting another’s survival or reproduction
Cooperation (helping)
helps others while also helping oneself
e.g. wolves hunting together
Altruism (helping)
helping others at a net cost to oneself
Acts of altruism make evolutionary sense if explained by which theories
kin selection and reciprocity
Kin selection
behavior that seems to be altruistic came about through natural selection bc it helps close relatives
Reciprocity
acts of apparent altruism can arise even among nonkin bc the altruism is actually a form of long-term cooperation
Naturalistic Fallacy
by social Darwinists equates what is natural with what is right
- why things are the way they are.
Deterministic Fallacy
the belief that genes control behavior in ways that cannot be altered by environmental experiences or conscious decisions
