lOMoARcPSD|383 406 3
Psychology
What is psychology?
Psychology is the scientific study of the mind and the brain, to explain behaviour.
People tend to accept almost every type of description that is given to them, if it is not too
specific. This is called The Forer Effect/ The Barnum Effect. The descriptions, such as
astrology, are too general so become meaningless.
Week 1, topic 1; Genes and Evolution The
genetic basis:
- In the 70s: they think your behaviour is based on your environment, not genes.
- In the 90s: they think your behaviour is based on genes, not environment. Therefore,
they thought parents were not needed in a child life growing up, because they will
turn out the same either way, since it is in their genes.
- In the 2010’s: they think the interaction between genes and environment determine
behaviour.
The human skin is made from small cells. Each cell contains a nucleus. Each human
nucleus contains 46 chromosomes. Chromosomes carry instructions on how the human
body must be build and operated. These chromosomes are made from coiled strands of
DNA.
The DNA molecule has a double helix. The rungs of this helix are made of
complementary cains of 4 bases:
- A: Adenina
- T: Thymine
- G: Guanine
- C: Cytosine
The sequence of the bases forms the biological information. Not all the couples are
compatible, so the sequence of the compatible pairs form the information. These smaller,
compatible parts are the human genes. The not-compatible cells are called non-coding
DNA.
DNA govern the cells functioning by providing instructions to make protein. If you want a cell
to make protein, you need Gene Expression. This is the extent to which a gene is
transcribed into a sequence of amino acids/ protein. The gene needs to be turned on to
make protein. If a gene is turned on depends on the biochemical environment of the cell.
This depends on the overall environment, behaviour, experience etc.
Cells grow differently when in different parts of the body, they also give off different
protein.
, lOMoARcPSD|383 406 3
A genotype is an organism’s specific set of genes. A phenotype is the genotype combined
with the environment. This shows the traits and behaviours of an organism.
The human development starts when a male and a female mate. Their genes are
brought over to the foetus. He gets 23 chromosomes from the egg, and 23 chromosomes
from the sperm. This makes 46 chromosomes, which is a perfect amount to construct the
human body and mind.
Each gene is paired with another, the pairs are corresponding chromosomes.
Allele is a specific pair of genes. You have homozygote, this is when the alleles on the
locus are the same, and you have heterozygote, that is when the alleles on the locus are
different.
When you have homozygote, you are 100% sure you get that gene, if you have
heterozygote, the dominant allele “wins”. The recessive allele loses.
A dominant allele means that you only need one allele to get the gene. A recessive
allele means that you need two alleles to get the gene.
A specific trait is determined by interaction between environment and either one gene pair,
or multiple gene pairs, which is called polygenetic inheritance.
The genome is shaped by evolution -> Darwin’s Evolution Theory.
Darwin’s evolution theory
All modern organisms descended from a small set of shared ancestors. These ancestors
have merged over time to be able to survive the best. This was caused by natural
selection. The weak organisms died off, while the organisms that were able to survive in
their period survived and evolved over time.
To make natural selection possible, you need enough variations in a population. The
individuals with certain strong traits need to survive and repopulate. The strongest traits of
the surviving organisms must be passed on to the next generations. This happens because
organisms adapt to the environment, they live in over generations survival of the genes, not
the organisms.
There is evidence for natural selection:
- The fossil Record
There are found transitions between certain species.
- The Resemblance between genomes of various species
Humans and moneys only differ from one chromosome; moneys have one more.
We share the same sequence in our chromosomes, we both have Telomere and
Centromere. The difference is that the human chromosome is fused, while the
monkey has two separates.
, lOMoARcPSD|383 406 3
- Pseudogenes
humans have ineffective genes that do nothing for us but used to have effect on
our ancestors. Via mutation it has been deactivated, but it has not been removed
via evolution.
- Distribution of species across the world
A continental island was one connected to the continent, Pangea. This explains why
there are a large variety of species on those islands. Oceanic islands are comparison
have lesser species. The only species that are originated at the islands are either
birds, insects, or fish, these are all long-distance travellers.
Evolution sceptical think that even though there is evidence, the evolution theory still should
not be in the curriculum. The argument against this is that evolution is not always positive. It
does not evolve a species to a higher level, it just adapts to its environment.
The nature – nurture debate is an ongoing debate in the science world. Nature stands for
genes and nurture stands for environment. A conclusion is that who we are, is based on how
our genes are expressed in certain environments. People who have a gene for anger issues
are more likely to get angry. Even though this fact, the environment that they grew up in a
probably still live in has a huge impact on how the handle this anger. This means there is a
higher probability that people with this gene get angry, but the environment can have an
impact.
, lOMoARcPSD|383 406 3
Week 1, topic 2; the brain and the nervous system
What is the nervous system made of?
There are two basic cells/ codes
- Glia; supportive function
- Neuron: receive information and transmit it to other cells.
Neurons are driven with electrical impulses and communicate with chemical signals.
Because of this neuron to neuron communications, a neutral network arises. When neurons
receive the signals, they take them in. While they are there, the signals are being evaluated.
When they are sent out, the neurons send out signals to other neurons.
Sensory (afferent) receptors are capable to translate a physical stimulus into an electric
signal. They do this through the spinal cord, to the brain. This neuron carries information
from the senses to the central nervous system.
Motor (efferent) receptors carry information from the central nervous system to the muscle
cells, this creates movement. Reflexes are automatic reactions that the motor receptors
create.
Interneurons are in between the afferent and the efferent neurons. They make
connections within the central nervous system.
Structure of a neuron
A neuron has many parts:
- Dendrites: receive signals from other cells.
- Nucleus: controls the entire neuron.
- Cell body: organizes and keeps the cell
functioning. Organizes information from
other dendrites.
- Nodes of Ranvier allows distribution of
Ions (Ka+, N+ etc.).
- Axon: transfers signals to other cells and
organs.
- Myelin Sheath: increases the speed of
the signal.
- Axon terminals: forms joints with other signals.
The synapse is the place where chemical communication
happens between neurons. This is an empty space in between
the send-neurons and the receive-neurons. A