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Lecture 3

Course Code
Michelle Hilscher

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PSYC18 -3
What is the origin of life?
- Depends on who you ask
o Christians: special creation
Believe that god created the universe
o Fossil record reveals:
1. Species change 2. Speciation 3. Extinction
Species alive v}ÁZ]v[Æ]]vZ
Early evolutionary theories (prior to Darwin)
- Jean-Baptiste Lamarck
o Transmutation of species: species change over generations
The use/lack of use of a body part can be transferred to offsprings
E.g. predicted that weightlifters will have big muscled babies
E.g. predicted that birds that are blinded will have blind offsprings
Soft heredity: belief that efforts to change phenotype can also change the
Non-evolutionary theories t precursors to Darwin
- Charles Lyell t geologist
o Solved a problem that was plagueing geologists
o W}ouWZ]v[vµu}µv}(]uZ}µv(}Zu}µv}(
species change
o Therefore he suggest that the earth is older that thought: 100million years old instead
of 2000-3000yrs old
- Thomas Malthus t English political economist
o Population growth rate > food growth rate
o Too many organisms and not enough food
o Creates a struggle for existence
o Fittest organism favoured
Charles Darwin
- Z>ÇoovDoZµ[Á}l
- Observes a huge variation between species and within species
- E.g. different beak size of Galapagos finches
o Large beaks for nuts and small beaks for berries
o Variation due to environmental variation
- Has to have the following:
1. Within species competition
o Population size vs resources
2. Heritable variations
o Phenotype tied to genotype
3. Conditions that differentially favour these variations
o predation
o E.g. peppered moths
o E.g. phototropism

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Moths have preference for light (emotion)
Sexual selection
- Making it to sexual maturity = basic survival
- Pressure to survive t self-preservation
- Pressure to find a mate t self-propogation
- Which behaviours and emotions:
o Help us survive?
o Help us to reproduce?
o Help us pass our genes to the next generation?
- We presume that emotions serve functions:
o Orienting t make us aware of a problem
o Organizing t coordinate our response
o Interacting t establish social bonds to find a mate
o Increase our chance of surviving and find a mate
- Wµo]Z^ZÆ]}v}(u}]}v]vuvvv]uo_
o How are emotions expressed in the face?
Also observed expression of actors that have no emotions attached to it and
compared to people from an asylum
o What noises do animals make when emotional?
How animals express anger or happiness
o Thought of expression in a multi-faceted way:
Face, body movements (tension, posture), vocalization
Darwin and emotional expressions as adaptations
- Emotional expression is merely an action that is used to directly aid with survival
o E.g. cat pulls back ears during a fight to prevent them being bit off
o XPXÁ}oÀu}µZZ]u}u[v}µ}ooZ}PµP](}}µ]vP-weaning
- At that time performed in conjunction with felt emotion
o E.g. anger; happiness and gratitude
o The action (pull ears back) originally linked to an emotion (fight t anger), animal will pull
ears back when it feels anger
- Emotion expression is an intention movement t suggests what actions may follow
o E.g. violence, submission
o Can show that cat is angry instead of engaging in a fight to preserve life
- Over time all it takes is the emotional expression, not the elaborate suite of actions themselves
o Expression is a better survival fuarantee
- Eventually, expression occurs even in situations where the action is useless or futile
Darwin, Antithesis, and Overflows
- Antithesis principle: approach signal is the exact opposite of the avoid signal
o XPX](µooZ]lÁZvvPÇUZvÁZvZ[v}vPÇZ]Á]ooµ
- overflows: puzzling gestures and vocalizations
o why we cry whvÁ[U}Z}µÁZvÁ
o e.g. shake hand when struck painful
o have no function but are release of pent-up energy
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