This is a comprehensive and detailed lecture note for psychology and genetics, it also includes summary boxes and additional reading notes.
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Lecture 1 (introduction)
Darwin- the problem of History
Animals have the same bone
structures, or described in the same
way.
Similar structures, different functions.
Arrange natural world into different
hierarchy's. Reason for similarity
between species are because things in
these categories are related to each
other. Humans close to ape distant to
vertebrates.
Darwin said for animals to be closely related they share a common ancestor, more closely
related they are, more recent ancestor was.
Species are not fixed change over time = Descent with modification
Darwin the problem on design
Organisms appear well-adapted for their surroundings.
Some structures make no adaptive sense. E.g. Whale
has pelvis, which has no function, whales evolved from
land creatures.
Darwin realises that both adaptation and vestigial
structures could be explained if there was slight
changes in form of animals occurring each generation,
useful ones retained, less useful disappear.
Darwin's theory
1. Variation in populations
2. Hereditary- variations passed from parents to offspring.
3. Competition- some individuals reproduce more than others.
4. Natural selection
Homologies and analogies
Homologies are similarities between organisms due to common ancestry.
Analogies are similarities due to parallel selective pressures
, Genetics: The modern synthesis
Darwin understood that parents pass characteristics to their offspring, but did not know how it
worked.
Mendel- was working on this in Czech Republic but was not well known.
Common objections and misunderstandings:
"Evolution is just a theory"
Drought in birds, bigger seeds survived, birds adapted had bigger beaks to eat the bigger
seeds. Offspring of birds had bigger beaks- evolution has happened.
"There are gaps in the [fossil] record"
Fossilisation is hit and miss process. Not all forms represented in fossil record.
"Something like this is too complex to happen by chance."
"Evolution is all about the past, I care about the future"
Summary
Darwin’s theory solves the problem of history and the problem of design in the living world
Patterns of homology and divergence seen in the natural world are best explained by
descent with modification from a common ancestor
The adaptation of organisms to their environments is best explained by non-random
retention of beneficial variations cumulating over long periods of time
Darwin’s theory was integrated with genetics in the modern synthesis
Many common objections and misunderstandings can be easily clarified
,Lecture 2 (chpt 2)
Environment and genes play important part in determining things like height.
Genotype = Gene makeup.
Variant of the gene is the allele.
Phenotype = Characteristics, trains you have that we can measure (eg personality)
Phenotype determined by the property of proteins in its cells.
Darwin said that variations in phenotype could be heritable.
Cells:
Most DNA is found in nucleus, but some in the
mitochondria.
99% of DNA in nucleus
1% in Mitochondria. DNA found in
mitochondria is from mum not dad and similar to
bacteria.
Cell membrane = enveloping the cell contents
Ribosomes = substances needed in cell function are synthesized.
Mitochondria = energy power house, glucose and other fuels are broken down to release energy.
Eukaryotes organisms such as animals and plants whose cells have nuclei and mitochondria.
Prokaryotes organisms such as bacteria, many principles the same but some of the details are
different.
Proteins:
make up 12-18% of total body weight in humans particularly significant.
Give cells their shape and structure
Form connecting tissues
Function as hormones and as antibodies
Serve as enzymes which control the many chemical reactions that are needed for the body to
function and to create or acquire other types of molecules that it requires.
Large molecules made up of chains of amino acids.
Amino acids:
20 different kinds
Sequence of amino acids determines what the properties of the protein will be.
DNA= Deoxyribose Nucleic Acid
stuff genes are made of.
DNA molecule has two strands, each of which mirrors the
information in the other through the principle base pairing.
A (adenine) and T (thymine)
G (guanine) and C (cytosine)
Between pairs is weak hydrogen bonds.
, DNA is wound by proteins called histones.
Long-chain molecule or polymer, consisting of 2 strands bound to each other and twisted
around in a double helix.
Chemical bonds within each strand are extremely strong = covalent bonds.
Bonds between the two strands are weaker = hydrogen bonds.
2 strands referred to as sense and anti-sense strands.
Chromosome = long length of DNA.
Sections on the chromosome that are called Gene.
Humans have 46 chromosomes in 23 pairs.
Sex chromosomes determine sex male/female. XX female; XY=male
Autosomes pairs 1-22.
2 versions of each chromosome one from mum one from dad.
Diploid = two copies of each chromosome
Gene = information in coded form. Information you need to build a functioning body.
Genes = sequence of DNA bases
Form proteins which is sequence of amino acids
Allele= alternative form of a gene
A different allele will often lead to the formation of a different sequence of amino acids, and
therefore form of different protein.
Watson and Crick resolution of the structure of DNA, won Nobel prize 1962.
Genes have 2 functions: influence the physical characteristics of the organism. Genotype
influences the Phenotype. Genes replicate themselves to produce new cells or new individuals
with same genotype.
Transcription and translation
RNA forms on open side of DNA.
G and C
A with U (not T with RNA)
MRNA Transcription- making copy of DNA
Translation= Ribosome, reads the mRNA to
translate (read) the bases to make particular
amino acid. Then protein chain is released.
RNA once formed is separated from DNA and
DNA zips itself back up.
RNA transported to ribosomes.
mRNA = messenger RNA
RNA = Ribonucleic acid; chemically similar to single strand DNA except T is replaced with U
(Uracil).
How does it work?
4 bases code for 20 amino acids.
3 bases in a row show what amino acid to put where = codons.
E.g. Lysine = AAA, AAG
System is redundant lots of different ways to make the same thing.
Codons differing by first base (e.g. CCU and GCU) produce amino acids chemically similar to
each other.
Errors to transcription and translation are common.
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