Comparative Psychology
Evolution
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What is evolution & why are psychologists
interested?
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How do men and women attract/choose
sexual partners?
How has evolution shaped sexual behaviour
(e.g. jealousy, infidelity)?
Has evolution affected how men & women
approach child-rearing?
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Reproductive behaviour
Evolution
Charles Darwin’s attempt to explain the
huge variety of living things…
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…in a scientific way
…without drawing upon religious ideas
Each living thing (organism) has a set of
characteristics encoded by its genes
The organism inherits its genes from its
parent(s)
Variations between organisms are caused
by variations in the genotype
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Evolution
Evolution
Organism
Organism has
particular
characteristics
determined by its
genes
Environment
contains a range of
opportunities and
threats (e.g. food
sources, predators)
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Environment
Evolution
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Exploit the opportunities available in its
environment
Avoid or deal with the threats presented by its
environment
We call this the organism’s fitness
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An organism’s ability to survive depends
on how well its characteristics allow it to:
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Fitness
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Fitness
Yummy!
Evolution
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Consequently, they are more likely to mate
and have offspring
They pass on their genes to the next
generation
Gradually, the genes for successful
characteristics spread through the
population
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Fit organisms are more likely to survive
into adulthood than unfit ones.
Evolution
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The environment changes over time –
sometimes gradually, sometimes rapidly
So a characteristic/gene that is adaptive at
one time may become maladaptive if the
environment changes
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Fitness is all about how well an organism
is adapted to its environment
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Fitness
Arse.
Evolution
Genotypes change due to:
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Random mutation of DNA
Recombination of genes due to mating
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Species compete with each other – the fittest
‘wins’ by reproducing more effectively
Species go extinct when their environment
disappears or they are out-competed
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New species emerge as adaptive changes
spread through a population
Characteristics acquired during the
lifespan can be passed on to offspring
Humans are descended from monkeys
Other animals are ‘less evolved’ than us
Humans are the ‘end product’ of evolution
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Evolution Myths
Evolution & Psychology
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Assumes that behavioural characteristics can
be inherited just like physical ones
Tries to explain human behaviour/psychology
in terms of evolutionary processes
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Evolutionary psychology regards humans
as subject to same evolutionary processes
as other animals (continuity)
Evolution & Psychology
Physically weak
Lacking agility
Poor climber
Small teeth
No claws
Large brain
Planning
Imagination
Language
Social
organisation
Tool use
Highly dependent
young
Communication
Poor night vision
Problem solving
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Slow