Lecture 1 genes and evolution
Overview
- The genetic basis
- Evolution by natural selection
- Genes and behavior
Psychology
- Psychology is the scientific study of mind, brain, and behavior (Phelps, et al., 2022).
o Lectures: not appropriate definition: bottom one better
Whole purpose is to explain and predict behavour
- Psychology is the scientific study of mind and brain to explain behavior.
- Why do we need a science for that?
o Most people already have knowledge about how other people act but they might not
really understand it exactly
o Other people hold beliefs about other people
o because common sense fails
- why do people belief that general descriptions fit their personality
o do not realise that a lot of other people will also believe in this description
o astrology is part of that as well
The genetic basis
history
- Is it correct to claim that “a violent person has violent genes”?
o Depends on when the question is answered
o in the seventies -> no
environment -> (violent) behavior
o in the nineties -> yes
Genes -> (violent) behavior
o today ?
genes <-> environment <-> (violent) behavior
interaction is important
Genes
- meaningful sections of the DNA molecule
- govern the cell’s functioning by providing instructions for making proteins
- presence of a gene does not always mean that a protein will be produced
,Gene expression
- whether a gene is turned “on” or “off”; the extent to which a gene is transcribed into a
sequence of amino acids (protein)
- methylation: methyl group is attached to gene to silence the gene
- In each cell, some genes are expressed at any point in time and others are not. This is
controlled by the biochemical environment inside the cell.
o The biochemical environment inside cell is influenced by e.g., environment outside
the cell, timing in development, the overall environment, experience, behaviour.
Genotype and phenotype
- Genotype
o an organism’s specific set of genes
- Phenotype
o the overt traits and behaviours of an organism
o Phenotype is determined by genotype x environment (experience, past and present).
Twins
- Monozygotic (identical) twins have the same genotype but different environments.
- Can look different from each other
o Can be explained by subtle difference in gene expression, mostly caused by
differences in environments
The genetic basis
- Each gene is paired with another gene.
o The pairs are located at corresponding positions on pairs of chromosomes.
o Allele is one specific variant of a gene.
Dominant
Recessive
o Homozygote: alleles on locus are the same
o Heterozygote: alleles on locus are different
- A specific trait or behavior is determined by the interaction between the environment (past
and present) and
o one gene pair: monogenetic inheritance
o multiple gene pairs: polygenetic inheritance.
- Where do our parent’s sets of genes come from?
o from their parents
o from their parents etc. etc. etc. etc.
- The genome is shaped by evolution over the years ‐> Darwin’s evolution theory
Evolution by natural selection
- Charles Darwin hypothesized that all modern organisms
o are descended from a small set of shared ancestors.
o have merged over time through the process of evolution.
,Natural selection conditions
- Three conditions
o There is variation among individuals of a populations
o Individuals with a certain trait survive and reproduce at higher rates than others
o The trait associated with this advantage is passed from parents to offspring
- Specific traits will be better represented in the next generation.
- It does not follow that evolution
o somehow improves organisms at some point but not forever an advantage
o can only lead to rigid behavioural patterns: ability to adapt and be flexible could have
been an advantage in the past
Gene inheritance
- Organisms differ in genotype and variations in genotype are passed on
- What matters is the survival of genes, not the survival of individuals.
o So it does not matter if the parent survives while giving this gene to offspring
Evidence of evolution by naturel selection
- The evidence for modern evolutionary theory comes from many sources
o the fossil record
research revealed that fossils exist after Darwin already died
o the resemblance between genomes of various organisms
apes and humans different amount of chromosomes
explained by 3 telomeres present in chromosome 2
o fusion product of 2 separate chromosomes
o pseudogenes
inactive gene that does not function due to mutations
only one step of vitamin c pathway is missing due to inactivating mutation
same in all primates
o distribution of species across the world
Continental islands versus oceanic islands
Continental: used to be attached to the mainland
Oceanic: originated in the seas for example due to volcanos
Sceptics of evolution by natural selection
- Despite overwhelming evidence, people remain sceptical about the theory of evolution.
o Creationism: live originates from different designers
o Any other theory than evolution: fate, but not an alternative theory to evolution
Genes and behavior
- Nature (genes) versus Nurture (environment)
o The nature nurture debate has become increasingly irrelevant.
- Instead, there is a continuous interaction between genes and environment!
- Who we are is determined by how our genes are expressed in distinct environment
- Is it correct to claim that “a violent person has violent genes”?
- Genes set the limit
o Environment causes the rest
, Lecture 2 The Brain and the Nervous System
Overview
- Building blocks of the nervous system
- Communication among neurons
- Communication of the brain with the body
- Studying the brain
- The brain
Building blocks of the nervous system
- Nervous systems
o Central: brain, spinal cord
o Peripheral: rest
- The nervous system is made up of two basic kinds of cells
o Glia
o Neurons
Neurons
types of neurons
- Sensory receptors
o Will translate physical signals to signals
- Sensory (afferent) neurons
- Motor (efferent) neurons
- Interneurons
o Neurons between sensory and motor neurons
Communication among neurons
- Neuron is covered by a fatty membrane
o Semipermeable
o Does not dissolve in environment
- Potential difference inside and outside the neuron
o Difference in charge
o Different number of charged ions
o Measured by voltage meter
- Action potential: neuron gets positively charged compared to environment
- Neurons either fire or do not fire
o All‐or‐none law
Intensity variations by
variations in the number of neurons firing.
variations in firing rate.
- Neurons interact
o via synapses.
o through chemical substances.
Overview
- The genetic basis
- Evolution by natural selection
- Genes and behavior
Psychology
- Psychology is the scientific study of mind, brain, and behavior (Phelps, et al., 2022).
o Lectures: not appropriate definition: bottom one better
Whole purpose is to explain and predict behavour
- Psychology is the scientific study of mind and brain to explain behavior.
- Why do we need a science for that?
o Most people already have knowledge about how other people act but they might not
really understand it exactly
o Other people hold beliefs about other people
o because common sense fails
- why do people belief that general descriptions fit their personality
o do not realise that a lot of other people will also believe in this description
o astrology is part of that as well
The genetic basis
history
- Is it correct to claim that “a violent person has violent genes”?
o Depends on when the question is answered
o in the seventies -> no
environment -> (violent) behavior
o in the nineties -> yes
Genes -> (violent) behavior
o today ?
genes <-> environment <-> (violent) behavior
interaction is important
Genes
- meaningful sections of the DNA molecule
- govern the cell’s functioning by providing instructions for making proteins
- presence of a gene does not always mean that a protein will be produced
,Gene expression
- whether a gene is turned “on” or “off”; the extent to which a gene is transcribed into a
sequence of amino acids (protein)
- methylation: methyl group is attached to gene to silence the gene
- In each cell, some genes are expressed at any point in time and others are not. This is
controlled by the biochemical environment inside the cell.
o The biochemical environment inside cell is influenced by e.g., environment outside
the cell, timing in development, the overall environment, experience, behaviour.
Genotype and phenotype
- Genotype
o an organism’s specific set of genes
- Phenotype
o the overt traits and behaviours of an organism
o Phenotype is determined by genotype x environment (experience, past and present).
Twins
- Monozygotic (identical) twins have the same genotype but different environments.
- Can look different from each other
o Can be explained by subtle difference in gene expression, mostly caused by
differences in environments
The genetic basis
- Each gene is paired with another gene.
o The pairs are located at corresponding positions on pairs of chromosomes.
o Allele is one specific variant of a gene.
Dominant
Recessive
o Homozygote: alleles on locus are the same
o Heterozygote: alleles on locus are different
- A specific trait or behavior is determined by the interaction between the environment (past
and present) and
o one gene pair: monogenetic inheritance
o multiple gene pairs: polygenetic inheritance.
- Where do our parent’s sets of genes come from?
o from their parents
o from their parents etc. etc. etc. etc.
- The genome is shaped by evolution over the years ‐> Darwin’s evolution theory
Evolution by natural selection
- Charles Darwin hypothesized that all modern organisms
o are descended from a small set of shared ancestors.
o have merged over time through the process of evolution.
,Natural selection conditions
- Three conditions
o There is variation among individuals of a populations
o Individuals with a certain trait survive and reproduce at higher rates than others
o The trait associated with this advantage is passed from parents to offspring
- Specific traits will be better represented in the next generation.
- It does not follow that evolution
o somehow improves organisms at some point but not forever an advantage
o can only lead to rigid behavioural patterns: ability to adapt and be flexible could have
been an advantage in the past
Gene inheritance
- Organisms differ in genotype and variations in genotype are passed on
- What matters is the survival of genes, not the survival of individuals.
o So it does not matter if the parent survives while giving this gene to offspring
Evidence of evolution by naturel selection
- The evidence for modern evolutionary theory comes from many sources
o the fossil record
research revealed that fossils exist after Darwin already died
o the resemblance between genomes of various organisms
apes and humans different amount of chromosomes
explained by 3 telomeres present in chromosome 2
o fusion product of 2 separate chromosomes
o pseudogenes
inactive gene that does not function due to mutations
only one step of vitamin c pathway is missing due to inactivating mutation
same in all primates
o distribution of species across the world
Continental islands versus oceanic islands
Continental: used to be attached to the mainland
Oceanic: originated in the seas for example due to volcanos
Sceptics of evolution by natural selection
- Despite overwhelming evidence, people remain sceptical about the theory of evolution.
o Creationism: live originates from different designers
o Any other theory than evolution: fate, but not an alternative theory to evolution
Genes and behavior
- Nature (genes) versus Nurture (environment)
o The nature nurture debate has become increasingly irrelevant.
- Instead, there is a continuous interaction between genes and environment!
- Who we are is determined by how our genes are expressed in distinct environment
- Is it correct to claim that “a violent person has violent genes”?
- Genes set the limit
o Environment causes the rest
, Lecture 2 The Brain and the Nervous System
Overview
- Building blocks of the nervous system
- Communication among neurons
- Communication of the brain with the body
- Studying the brain
- The brain
Building blocks of the nervous system
- Nervous systems
o Central: brain, spinal cord
o Peripheral: rest
- The nervous system is made up of two basic kinds of cells
o Glia
o Neurons
Neurons
types of neurons
- Sensory receptors
o Will translate physical signals to signals
- Sensory (afferent) neurons
- Motor (efferent) neurons
- Interneurons
o Neurons between sensory and motor neurons
Communication among neurons
- Neuron is covered by a fatty membrane
o Semipermeable
o Does not dissolve in environment
- Potential difference inside and outside the neuron
o Difference in charge
o Different number of charged ions
o Measured by voltage meter
- Action potential: neuron gets positively charged compared to environment
- Neurons either fire or do not fire
o All‐or‐none law
Intensity variations by
variations in the number of neurons firing.
variations in firing rate.
- Neurons interact
o via synapses.
o through chemical substances.
