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Lecture 2

PSYCH 1XX3 Lecture Notes - Lecture 2: Blue Ocean Strategy, Assistive Technology, Genetic Drift

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Joe Kim

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Evolution I
- Adaptation:
Biological traits that help an individual survive and reproduce in its habitat
Perform a speci"c function
Always “for” something
Make an organism better suited to its environment
- Eyes able to recognize and respond e*ectively to things around you by
detecting and analyzing the re+ected light
- Racoons are primarily nocturnal and while they do not have night vision, their
front paws have adapted to become so sensitive that they often don’t require
vision to discriminate food items from non-food items in total darkness
- Bats discriminate easily between a falling leaf and a moth +uttering in the
night using their sophisticates echolocation system
- Enable organisms to interact with a complex physical environment
Cognitive Processes
- Can we consider mental processes as adaptations?
- Cognitive Psychologists:
Study selective attention, memory encoding, retrieval (tasks that the mind
needs to accomplish to do its job
Refer to the adaptive functions of mental activity
Break down large scale cognitive processes into adaptive problems or
tasks and then look for the adaptations that solve those problems
- Adaptive functions of our minds evolve through natural selection
Evolution by Natural Selection
- Adaptations emerge in development as the result of activation of relevant
genes in interaction with relevant aspects of the environment
- Natural Selection:
Formalized by Charles Darwin and Alfred Russel Wallace
One of 4 basic mechanisms of evolution
Others are mutation, genetic drift and migration
Di*erential survival and reproduction of organisms as a result of the
heritable di*erences between them
- Three Components to Their Insight:
1. Signi"cant Individual Di*erences:
Variation among individuals for any given characteristic
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2. Di*erences A*ect Individuals’ Chances of Surviving and Reproducing:
Causes di*erential reproduction
Some individuals will have more o*spring than others
3. Traits are Heritable:
Traits that give rise to di*erential reproduction have a genetic basis
O*spring of successful reproducers will resemble their parents with
respect to these variable characteristics
Selective Transmission
- Example of Darwin’s observations of populations of birds in the Galapagos
Population of "sh that vary in colour and other traits
Some are blue, some are red
Blue are well camou+aged in the blue ocean water and red are more
visible to predators
Red "sh get eaten more often
Blue "sh survive and reproduce more often than the red "sh
Blue "sh tend to have blue coloured o*spring because body colour is a
heritable trait
Over successive generations there will be selective transmission of
heritable parental traits
Population will be mostly blue
Speci"c characteristics that are best adaptive for survival and
reproduction are going to be reproduced at higher rates
Process continues and the entire "sh population will become blue
Stabilizing Selection
- Selection against any sort of departure from the species-typical adaptive
- Tends to keep traits stable over generations
- Ex.
Blue would remain the most common colour in our "sh population
because it is adaptive and minimizes the risk of predation
- In some cases (especially when there is a major change in the environment)
selections favours traits that are not typical and evolutionary change can be
observed (sometimes rapidly)
Darwin’s Finches
- Classic example of evolutionary change
- Studying beak shape and size in a species of birds called “Medium-Ground
- Able to observe natural selection within only one generation
Drought caused vegetation to be wiped out and small seeds were eaten
up quickly
Bigger beaks were able to crack larger seeds that they usually didn’t
bother with
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