Inleiding psychologie
Genes and evolution
Psychological science: the study, through research, of mind, brain, to explain behavior >
understanding people’ s minds or predicting others’ behavior
Mind: mental activity > memories, thoughts, feelings, and perceptual experiences (zintuigen)
Behavior: totality of observable human (or animal) actions (subtle > complex), interaction
between environment, one gene pair, and polygenetic inheritance
The mind (mental activity) is produced by biochemical processes in the brain
Stress has physiological consequences > impact the brain in uneven but predictable ways.
Mild stress > diminish functions of brain regions = think flexibly, execute long-term
goals, control emotions
Everyday events (running late) > affect higher brain functions
Physiological processes (nervous system)- activity of cells > basis of
psychological processes
Environmental factors can affect gene expression- whether a particular
gene is turned on or off > Methylation group attached to gene.
On > transcript in protein (sequence of amino acids)
Off > no protein
Influence how a gene (turned on) influences our thoughts, feelings, behavior Mutually
influence
Genetic predispositions influence the environment each other
Gene expression is controlled by the biochemical environment inside the cell (influenced by
environment outside the cell, timing in development, the overall environment, experience,
behavior)
Transplantation to different areas > different gene expression in cells
Absence of physical activity > different environment inside > micro level and global level
Genome: provides detailed genetic instructions, and options > environment determines
which option is taken. > shaped by evolution
Chromosome: (every cell 23 pairs) made up of DNA > comprise individual genes: the units of
heredity (erfelijkheid) that help determined an organism’s characteristics.
Polypeptide: building blocks of proteins (eiwitten) (basic chemicals > structure of cells and
direct activities> environment determines which are produced and when)
Allele is one specific variant of a gene
- Homozygote: alleles on locus are the same (AA)
- Heterozygote: alleles on locus are different (Ab)
,DNA > meaningful sequences > blueprints of producing of proteins > genes
Adenine (A) – Thymine (T), Guanine (G) – Cytosine (C)
Gene: a particular sequence of DNA that provides instructions for building polypeptides and
subsequently proteins.
- Dominant: expressed in the offspring whenever it is
present. A
- Recessive: expressed only when it is matched with a
similar gene from the other parent. a
Human Genome Project: map the entire structure of
human genetic material > 30.000 genes
Genotype: an organism’ s specific set of genes, the genetic constitution of an organism,
determines at the moment of conception.
Phenotype: the overt traits of behaviors of an organism (genotype x environment)
observable physical characteristics, which result from both genetic and environmental
influences.
Polygenic: influences by many genes (as well as by environment)- such as skin color
Zygote: fertilized egg > grows through cell division (= basis of the life cycle and is responsible
for growth and development, mitose en meiose)
- Monozygotic twins (identical): result from one zygote > same genes
- Dizygotic twins (fraternal): result from two zygotes
Mutations: alterations in the DNA
- Adaptive: selective advantage in terms of survival or reproduction
- Maladaptive: selective disadvantage in terms of survival or reproduction
Industrial melanism: dark pigmentation (melanism) has evolved in an environment affected
by industrial pollution
Behavioral genetics: the study of how genes and environment interact to influence
psychological activity
Heredity: (erfelijkheid) transmission of characteristics from parents to offspring through
genes.
Heritability: a statistical estimate of the extent to which variation in a trait within a
population is due to genetics. > understanding population as a whole, not an individual >
estimates aid in identifying the causes of differences between individuals in a population
,Gene (MAOA) controls > enzyme monoamine oxidase (MAO) > two forms: higher and lower
level of MAO.
- MAO degradation of a class of neurotransmitters called monoamines- dopamine,
serotonin, norepinephrine.
- Low-MAOA-gene > violent behavior
Epigenetics: (“on top of genetics”) the study of how environment changes genetic
expression in a way that might be passed along to offspring
Optogenetics: technique that provides precise control over when a neuron fires > combines
the use of light with gene alterations
Genetic manipulation > changing one gene’s expression leads to the expression or
nonexpression of a series of other genes > behavior can change.
Genes seldom work in isolation to influence mind and behavior
Charles Darwin evolution theory 1859: trip on a ship 1831 > observations > inspired to write
ideas on evolution
Natural selection:
- Variation among individuals of a population
- Individuals with a certain trait survive and reproduce at higher rates than others
- The trait associated with this advantage is passed from parents to offspring
Reproductive advantage in specific environment > repeated > adapted to specific
environment
Evidence for modern evolutionary theory
The fossil record: Darwin predict that the earth is much older > more species
-show specific splits, transition forms, order in how organs develop, order of time
The resemblance between genomes of various organisms
Pseudogenes (2000 in an human body): genes that do not produce protein because
they don’t function anymore > mutation. Enzyme makes vitamin C out of glucose
Distribution of species across the world
- Continental islands: once connected to the continent- such as Japan
Travel from the content > more species on the island
- Oceanic islands: (volcanic islands)- such as Hawaii
Making of vitamin C >four steps, three active steps, last step doesn’t work > pseudogene
Centromere > links chromosome
Telomere > protects chromosomes from damage during the cell division process
Nature (genes)
Nurture (environment)
Genes Environment Behavior
, The brain and the nervous system
Nervous system:
The central nervous system (CNS): brain and the spinal cord
The peripheral nervous system (PNS): all other nerve cells and includes:
-somatic nervous system: voluntary behavior (picking something up)
-automatic nervous system: less voluntary behavior (controlling heart rate)
PNS sends information to CNS > organizes and evaluates information and directs PNS
Glia: cells in the nervous system that have a supportive function
Neurons: cells that receive, integrate, and transmit information. They operate through
electrical impulses, communicate with other neurons through chemical signals and form
neural networks.
Sensory neurons > detect information from the real world > brain > translate signals
-somatosensory: information from skin and muscles
Motor neurons > direct muscles to contract or relax > movement
Interneurons > stations facilitating communication between sensory and motor
Neuron structure:
Dendrites: detect information from other neurons
Axons: information is conducted from the cell body to the terminal buttons
- Covered by myelin sheath (made up from glia cells) > allow faster movement of
electrical impulses along the axon
Cell body (soma): information received is collected and integrated
Terminal buttons: release chemical signals from the neuron into the synapse
Synapse: the site where chemical communication occurs between neurons
Neuron covered with a membrane: semi permeable > selectively allow molecules to leave or
enter the cell. Outside: positive, inside: negative
Action potential (neural firing) > the electrical signal that passes along the axon > terminal
buttons to release chemicals that transmit to other neurons. > difference between inside
and outside is positive > one selective part of the membrane >change occurs locally (+40mV,
-55MV)
