Transcript Genetics Powerpoint - Solon City Schools

Genetics, Evolutionary Psychology,
and Behavior
3C
1
Behavior Genetics: Predicting
Individual Differences
Behavior Geneticists - study our differences
and weigh the relative effects of heredity
and environment.
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Nurture and Human Diversity
Environment:
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Genes: Our Codes for Life
Chromosomes –
•Any genetic basis for a trait are located
in chromosomes
•23 from mother and 23 from father
•DNA (deoxyribonucleic) –
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Genes: Our Codes for Life
Genes –
•Capable of synthesizing a protein
•One or more genes are responsible for
expression or repression of a particular
trait
5
Genome
Genome • human genome makes us human
•the genome for drosophila makes it
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Twins Biology
• Monozygotic
(identical twins) –
• Dizygotic (fraternal
twins) –
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Twin Biology
Studying the effects of heredity and environment on
twins
1. Identical twins raised together 1. Identical twins raised apart –
1. Fraternal twins –
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Twins Studies
Identical twins raised separately
Twin Studies
Caution: any two strangers are likely to share
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coincidental similarities.
IdenticalTwins and IQ
• Bouchard Study
• .69 Correlational
coefficient for IQ tests
of
• .88
IdenticalTwins and
Personality
Temperament •Identical twins express similar
temperaments, suggesting heredity
predisposes temperament.
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Separated Twins and
Personality
•Identical Twins separated at birth – no
extreme differences in personality
•Differences between fraternal twins are
greater than identical twins.
Twin Studies
Temperament, Intelligence
Abilities, Attitudes
Brain Waves, Heart Rate
Bob Sacha
Interests, Fears
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Adoption Studies and
Personality
•Adoptees - tend to be different from their
adoptive parents and siblings.
•Environment shared by a family’s children
has relatively no impact on their
personalities
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Personality
• Big 5 Traits
–
–
–
–
–
Extroversion
Agreeableness
Conscientiousness
Neuroticism
Openness
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Twins Studies
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Parental Influence
• Parents do influence:
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Heritability
Heritability refers to the extent to which the differences
among people are attributable to genes
Heritability is numerical value with a range from
 For human behavior, almost all estimates of heritability
are in the moderate range of .30 to .60.
Applies to populations not individuals
Two boys raised in a barrel with
identical environmental conditions would
have a heritability of ______?
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Heritability and Big 5
• Big 5 Traits
–
–
–
–
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Heritability
Extroversion
Agreeableness
Conscientiousness
Neuroticism
Openness
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Gene-Environment Interaction
Genes and environment affect our traits
individually, but more important are their
interactive effects.
Alessia Pierdomenico/Reuters/Corbis
Rex Features
People respond differently to
Rowan Atkinson (Mr. Bean) than Orlando bloom.
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The New Frontier:
Molecular Genetics
Molecular genetics is a branch extension of
behavior genetics that asks the question, “Do
genes influence behavior?”
It seeks to identify
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Evolutionary Psychology
Evolutionary psychology - studies the
evolution of behavior and
. mind using
principles of natural selection.
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Natural Selection
Natural selection - evolutionary process
through which
are passed
on to ongoing generations because these
traits help animals
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Artificial Selection
Biologists like Belyaev and Trut (1999) were
able to artificially rear and domesticate wild
foxes, selecting them for friendly traits.
L.N. Trur, American Scientist (1999) 87: 160-169
Any trait that is favored naturally or artificially
spreads to future generations.
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Human Sexuality
Gender Differences in Sexuality
Question (summarized)
Male
Female
Casual sex
60%
35%
Sex for affection
25%
48%
Think about sex everyday
54%
19%
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Mating Preferences
Females
Males
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Criticisms of Evolutionary
Psych
• Works backwards
• Underestimates
• Unethical and immoral men could
use explanations to
• Does not consider the importance
of