Review

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• Review
• Evidence in favor of evolution by natural
  selection
• Existence and pattern of the fossil record.
• Homology.
• Universality of genetic code.
• Analogy with plant and animal breeding.
• Direct observation.
• 6? Adaptations?

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-Evolutionary approach to brain, mind and
behavior -Proximate vs. ultimate -Mind is
specialized -Mind is not a blank slate
(language, face recognition, sexual desire, mate
choice, parental solicitude -Human nature
causes culture it is not caused by culture
universals.
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-Natural selection occurs when replicating
entities have high copying fidelity relative to
their differential rates of replication. -Natural
(and sexual) selection builds adaptations that
are built of existing variation
(mutations). often formed slowly often formed
cumulatively specialized costly may be out of
date
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-Natural (and sexual) selection
builds adaptations that are good for The
species? The group? The individual? The gene?
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S S S S SS S S S S S S
A A A A AA A A A A A
S A S S S A A A S S A
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S S S S SS S S S S S S
A A A A AA A A A A A
S
SELFISH MIGRANTS CAN INFECT A GROUPS
S
AND CONVERT THEM INTO MIXED GROUPS
S A S S S A A A S S A
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S S S S SS S S S S S S
A A A A AA A A A A A
S
SELFISH MIGRANTS CAN INFECT A GROUPS
S
AND CONVERT THEM INTO MIXED GROUPS
WHICH BECOME PURE SELFISH GROUPS
S A S S S A A A S S A
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WHICH TEND TO GO EXTINCT
S S S S SS S S S S S S
A A A A AA A A A A A
S
SELFISH MIGRANTS CAN INFECT A GROUPS
S
AND CONVERT THEM INTO MIXED GROUPS
WHICH BECOME PURE SELFISH GROUPS
S A S S S A A A S S A
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Evolution by Natural Selection tends to make the
mean phenotype converge on the optimum.
frequency
trait value
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Sexual Selection Type of natural
selection. Selection builds adaptations of all
types. Sexual selection builds adaptations that
increase mating success 1. more mates 2.
better mates
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Challenges for ancestral males
quantity. Challenges for ancestral females
quality. Likely to produce divergent
adaptations Two optimal phenotypes Sex
differences parallel those in other primate
species.
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Facultative adaptations monitor environmental
variation and adjust phenotype accordingly. Select
ion favored genes that produce the right pattern
of environmental responsiveness The effects of
experience are pre-programmed by natural
selection. Violence
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Genetic fallacy Traits shaped by evolution
(biology) are fixed and inflexible. Oh really?!?
What about facultative traits? Norm of reaction
tells you how to change the trait.
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• Two nature/nurture questions!
• Why is my skin this color?
• causes of development (interaction)
• 2. Why do people differ in skin color?
• causes of variation
• (partition the variance)

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If we want to know how heritable a trait is h2
Vg/Vp, thus h2 Vg/(VgVe) h2 varies from 0 to
1. Selection is more effective when heritability
is significant but selection typically reduces
heritability as it works.
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Heritability of facultative traits? Relatively
low because of response to environment. But
obviously designed by selection! Nature/nurture
is misleading!
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Mendels hypothesis about the stuff of
heredity 1. Particles, not fluids (genes). 2.
Adults have a double dose of particles (diploid
adults). 3. Adults give only half of their double
dose to each offspring (haploid gametes). 4. Some
particles have stronger effects than others
(dominance).
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Gene expression How genes specify the recipes
for proteins
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Genetic variation and phenotypic variation
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Naturalistic fallacy whats natural is good. Oh
really!?! tsunamis, disease, aging and
death Understanding is not rationalizing. In the
case of facultative traits understanding points
the way to change.