PSYC*2410 Chapter 2: Evolution, Genetics, and Experience Flashcards
What is the general intellectual climate of a culture?
Zeitgeist
What is dichotomous thinking?
Thinking that involves viewing situations as having only two extreme options without considering any middle ground
What two questions demonstrate the tendency to think about behaviour in terms of dichotomies?
- Is it physiological or psychological?
- Is it inherited or learned?
What was the philosophical position of René Descartes?
Cartesian dualism
What is Cartesian dualism?
The belief that the universe is composed of two elements… physical matter and the human mind
What is aomatognosia?
A deficiency in the awareness of parts of one’s own body
What type of brain damage is typically involved in aomatognosia?
Damage to the right frontal and parietal lobes
What is the nature-nurture issue?
The debate about the relative contributions of genes (nature) and experience (nurture) to the behavioural capacities of individuals
Which side of the nature-nurture debate were most early North American experimental psychologists committed to?
The nurture side
Which side of the nature-nurture debate did most early European ethologists take?
The nature side
What is ethology?
The study of the behaviour of animals in their natural environments
What was the focus of early European ethology?
Instinctive behaviours
What are instinctive behaviours?
Behaviours that occur in all like members of a species, even when there seems to have been no opportunity for them to have been learned
What is problematic about the question “how much of it is genetic, and how much is experience?”
This type of questioning and thinking is based on the premise that genetic factors and experiential factors combine in an additive fashion
The model of the biology of behaviour boils down to the single premise that all behaviour is the product of the interactions among what three factors?
- The organism’s genetic endowment
- The organism’s experience
- The organism’s perception of the current situation
How do evolutionary psychologists attempt to understand behaviours?
By considering the evolutionary pressures that led to development of the behaviours
What type of psychological research focuses on comparing divergent mating behaviours of promiscuity and mate bonding?
Evolutionary psychology
What are the three types of mate bonding?
- Polygyny
- Polyandry
- Monogamy
What is polygyny?
One male bonds with multiple females
In which type of bonding are males not overly involved in the development of their young?
Polygyny
What is the most common type of mate bonding?
Polygyny
What is polyandry?
One female bonds with many males
In which type of bonding do males contribute more to the development of young than the females?
Polyandry
What is monogamy?
One male bonds with one female
What is the ultimate form of mate bonding?
Monogamy
What are the three key points emphasized by developments in evolutionary psychology?
- Evolutionary analyses can be applied to the most complex human behaviours
- Humans are the product of evolution
- Humans are closely related to other animal species
What were the four pieces of evidence presented by Darwin to support his assertion that species evolve?
- Fossil records
- Similarities among diverse species
- Selective breeding
- Evolution in progress
Darwin argued that evolution occurs through natural selection, based on what?
Fitness
What is natural selection?
The idea that heritable traits associated with high rates of survival and reproduction are most likely to be passed on to future generations
According to Darwin, what is fitness?
The ability of an organism to survive and contribute its genes to the next generation
How does social dominance contribute to evolution?
Dominant males tend to copulate more than non-dominant males and are thus more effective in passing on their characteristics to future generations
What are courtship displays?
An intricate series of behaviours that precedes copulation in many species
How are courtship displays thought to promote the evolution of new species?
By creating behavioural reproductive barriers
What is a group of organisms that is reproductively isolated from other organisms?
A species
When does a new species begin to branch off from an existing species?
When some barrier discourages breeding between a subpopulation of the existing species and the remainder of the species
What are two types of reproductive barriers?
- Geographic
- Behavioural
What are conspecifics?
Members of the same species
What are chordates?
Animals with dorsal nerve cords
What did chordates evolve from?
Complex multicellular water-dwelling organisms
What are vertebrates?
Chordates that posses spinal bones
What are the seven classes of vertebrates?
- Mammals
- Amphibians
- Reptiles
- Birds
- Three classes of fish
Which class must live in water during their larval phase, but can survive on land during adulthood?
Amphibians
What did reptiles evolve from?
Amphibians
Which class was the first to lay shell-covered eggs and be covered by dry scales?
Reptiles
What did mammals evolve from?
Reptiles
Today, most classification systems recognize about how many different orders of mammals?
26
T or F: Primates are difficult to categorize because there is no single characteristic possessed by all primates but no other animals.
True
What is the closest living relatives to humans?
Chimpanzees
What are primates of the same group that includes humans?
Hominins
What was one distinctive feature of the early Homo species?
The relatively large size of their brains
What kingdom are human classified under?
Animalia
What phylum are humans classified under?
Chordate
What class are humans classified under?
Mammal
What order are humans classified under?
Primate
What family are humans classified under?
Hominin
What genus are humans classified under?
Homo
What species are humans classified under?
Sapiens
What are the big three human attributes?
- Large brain
- Upright posture
- Free hands with an opposable thumb
T or F: Evolution proceeds in a single line.
False
T or F: Humans have little reason to claim evolutionary supremacy.
True
T or F: Evolution does not always proceed slowly and gradually.
True
T or F: Many products of evolution have survived to the present day.
False
T or F: Evolution does not proceed to preordained perfection.
True
T or F: All existing behaviours and structures are adaptive.
False
What are spandrels?
Traits that are non-adaptive by-products of and adaptive evolutionary characteristic (ex. belly buttons)
T or F: All existing adaptive characteristics evolved to perform their current function.
False
What are exaptations?
A characteristic that evolved to serve one function, but later became used for another
Do similarities among species mean that they have a common evolutionary origin?
No
What are homologous structures?
Structures that are similar between species because of a common evolutionary origin (ex. human arms and bird wings)
What are analogous structures?
Structures that are similar between species because of convergent evolution (ex. bird wings and bee wings)
What is convergent evolution?
Two independent species evolve to acquire similar characteristics due to similar environmental demands
T or F: There is now considerable evidence that Homo sapiens mated with other Homo sapiens (ex. Neanderthals)
True
What was the primary focus of early research on the evolution of the human brain?
Brian size
What seems to be the most reasonable approach to the study of brain evolution?
To compare the evolution of different brain regions
What are three important points about the evolution of the human brain?
- It has increased in size during evolution
- Most of the increase in size has occurred in the cerebrum
- An increase in the number of convolutions has greatly increased the surface area of the cerebral cortex
Can neural structures in the brains of one species typically be found in the same locations in the brains of related species?
Yes
What are two things Darwin didn’t understand?
- Why conspecifics differ from one another
- How characteristics are passed from parent to offspring
What were the two wise decisions Mendel made when designing his experiments with pea plants?
- He studies dichotomous traits
- He began his experiments by crossing the offspring of true-breeding lines
What are dichotomous traits?
Traits that occur in one form or another, never in combination
Which trait of a dichotomous pair is expressed in the phenotypes of heterozygous individuals?
The dominant trait
Which trait of a dichotomous pair is not expressed in the phenotypes of heterozygous individuals?
The recessive trait
In which type of breeding lines do interbred members always produces offspring with the same trait?
True-breeding lines
What is a phenotype?
An organism’s observable traits
What is a genotype?
The genetic makeup of an organism
What are genes?
Units of inheritance
What are alleles?
Two genes that control the same trait
What does it mean for an organism to be homozygous?
They possess two identical alleles for a particular trait
What does it mean for an organism to be heterozygous?
They possess two different alleles for a particular trait
What are the four central ideas of Mendelian genetics?
- There are two kinds of inherited factors (genes) for each dichotomous trait
- Each organism possesses two genes for each of its dichotomous traits (alleles)
- One of the two alleles for each dichotomous trait dominates the other in heterozygous organisms
- For each dichotomous trait, an organism randomly inherits one of its father’s alleles and one of its mother’s alleles
What are the threadlike structures in the cell nucleus containing genes?
Chromosomes
What type of molecule are chromosomes?
DNA molecules
Which process of cell division produces gametes?
Meiosis
What is genetic recombination?
The meiotic process by which pairs of chromosomes cross over each other at random points, break apart, and exchange genes
Which process of cell division produces cells with the same number of chromosomes as the parent cell?
Mitosis
What is replication?
The process by which the DNA molecule duplicates itself
What occurs during replication?
The two DNA strands unwind and the exposed nucleotide bases attract their complementary bases until the unwinding is complete and two DNA molecules have been created
What do most errors in replication take the form of?
Mutations
What term is used to describe the accidental alterations in individual genes?
Mutations
Which type of chromosome comes in matched pairs?
Autosomal chromosomes
What are autosomal chromosomes?
In mammals, all chromosomes except sex chromosomes
What are sex chromosomes?
The pair of chromosomes that determine an individual’s genetic sex
What are sex-linked traits?
Traits that are influenced by the genes on the sex chromosomes
What are the building blocks of protein?
Amino acids
What are long chains of amino acids?
Proteins
What are promoters?
Stretches of DNA whose function is to determine whether particular structural genes are converted into proteins via gene expression
What are activators?
Proteins that bind to DNA and increase gene expression
What are repressors?
Proteins that bind to DNA and decrease gene expression
What is gene expression?
A two-phase process in which the protein specified by a particular gene is produced
What are the two phases of gene expression?
- Transcription
- Translation
What occurs during transcription?
A strand of messenger RNA is transcribed from one of the exposed DNA strands and carries that genetic information from the nucleus into the cytoplasm of the cell
How do the nucleotide bases differ between RNA and DNA?
RNA has uracil and DNA has thymine
What occurs during translation?
The strand of recently transcribed mRNA is converted by a ribosome and tRNA into a protein
What is a codon?
A group of three consecutive nucleotide bases
What role do tRNA molecules play in translation?
They carry the complementary amino acids to ribosomes during protein synthesis
What is the Human Genome Project?
An international research effort to construct a detailed map of the sequence of all 3 billion nucleotide bases that compose human chromosomes
What were the three major contributions of the human genome project?
- New techniques for studying DNA were developed
- The discovery that humans have relatively few structural genes
- Many variations in the human genome related to particular diseases have been identified
What is the human proteome?
A map of the entire set of proteins encoded for my human genes
What are epigenetics?
The study of all mechanisms of inheritance other than those mediated by changed to the DNA gene sequence
What four human conditions “set the stage” for epigenetics?
- The human genome project
- The discovery that protein-encoding genes constitute only about 1% of human DNA
- The finding that the majority of RNA molecules were small
- The fact that the mechanisms by which gene-experience interactions took place were unknown
T or F: Non-gene DNA is junk DNA
False
What are the two most studied epigenetic mechanisms that can modulate gene expression?
- DNA methylation
- Histone remodelling
Which epigenetic mechanism involves methyl group attaching to DNA molecules?
DNA methylation
T or D: DNA methylation only decreases gene expression.
False. Can increase or decrease gene expression.
What is histone remodelling?
An epigenetic mechanism where histones change their shape, which influences the shape of the adjacent DNA
T or F: Histone remodelling only increases gene expression.
False. Can increase or decrease gene expression.
What is an epigenome?
A catalogue of all epigenetic mechanisms involved within a particular cell type
What is an epitranscriptome?
Refers to all modifications of RNA that occur after transcription and don’t involve modifications to the RNA base sequence
What is the subfield of epigenetics that examines the transmission of experience via epigenetic mechanism across generations?
Transgenerational epigenetics
What is ontogeny?
The development of individuals over their life span
What is phylogeny?
The evolutionary development of species
When both maze-dull and maze-bright rats were reared in enriched environments, what was discovered about the number of errors they made?
Maze-dull rats did not make significantly more errors than maze-bright rats
What is phenylketonuria (PKU)?
A neurological disorder whose symptoms include vomiting, seizures, hyperactivity, hyper-irritability, intellectual disability, brain damage, and high levels of phenylpyruvic acid in the urine
How is PKU transmitted?
A single gene mutation
Is the gene that causes PKU dominant or recessive?
Recessive
Which neurotransmitter is normally synthesized from tyrosine?
Dopamine
Individuals with what neurological disorder lack phenylalanine hydroxylase and as a result have an accumulation of phenylalanine?
Phenylketonuria (PKU)
Phenylalanine hydroxylase is required to convert phenylalanine into what?
Tyrosine
What must occur for a phenylalanine-restricted diet to effectively reduce the development of intellectual disabilities in people with high phenylalanine levels?
It must be initiated within the first few weeks of life
What are sensitive periods?
Intervals of time when an experience will have more of an effect on development
In the development of individuals, can the effects of genes and experience be separated?
No
In the development of differences among individuals, can the effects of genes and experience be separated?
Yes
What are monozygotic twins?
Twins that develop from the same zygote and are thus genetically identical
What are dizygotic twins?
Twins that develop from two zygotes and are as genetically similar as any other pair of siblings
In the Minnesota study of twins reared apart, what was found about the psychological profile of adult monozygotic and dizygotic twins?
Monozygotic twins were substantially more similar on all psychological dimensions than dizygotic twins, regardless of if they were raised in the same family environment
What are heritability estimates?
The proportion of variation in a population that can be attributed to inherited genetic factors
What does a heritability estimate of 0 mean?
Genes have no effect on phenotypic differences
What does a heritability estimate of 1 mean?
Genes contribute completely to the phenotypic differences
T or F: Heritability estimates indicate nothing about specific genes that contribute to a trait.
True
Can heritability estimates be interpreted as the proportion of genetic contribution to a particular trait?
No
If the environment in a study is uniform, will the heritability estimate be high or low?
High
What are most heritability estimates of complex traits and behaviours in the representative western samples that have been studied?
Between 40% and 80%
T or F: Monozygotic twins are epigenetically identical early in life, but differences accumulated as they aged.
True
What are disease-discordant monozygotic twin studies?
The examination of the epigenetic differences in monozygotic twins who are discordant for a particular disease
What is the multiplier effect?
People with similar genetic profiles tend to have similar experiences because they often seek out similar environments and engage in similar activities
