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Evolutionary timing – Molecular clock
Human evolutionary history
other Old World monkeys
‘apes’ and humans
upright posture
loss of tail
increased brain size
Humans show similarities with ‘apes’ (gibbons, orang, gorilla, chimps)
• shared derived traits: large brain, no tail, more upright posture
Human evolutionary history
other Old World
gibbons orang
monkeys
gorilla,chimps
and humans
brow ridge
loss of some hair
skull elongation
upright posture
loss of tail
increased brain size
Humans show similarities with African ‘great apes’ (gorilla, chimps)
• shared derived traits: elongated skull, less hairy, brow ridge
Human evolutionary history
other Old World
gibbons orang
monkeys
gorilla,chimps
and humans
?
brow ridge
loss of some hair
skull elongation
upright posture
loss of tail
increased brain size
Which are closer: gorilla & chimps, humans & chimps, human & gorilla?
Human evolutionary history
gorilla
chimps
human
gorilla
knucklewalking
morphology
chimps
human
?
similarities in
teeth, skull, genitals
Which are closer: gorilla & chimps or humans & chimps?
• are traits shared derived versus convergent / lost?
Human evolutionary history
gorilla
chimps
human
gorilla
knucklewalking
morphology
chimps
human

common ancestor
~5 million yrs ago
DNA similarities
similarities in
teeth, skull, genitals
Molecular data suggests chimps and human are close relatives
Human evolutionary history
gorilla
chimps
human
common ancestor ~5 mya
hunting, simple tools,
complex social behavior
DNA similarities
similarities in
teeth, skull, genitals
Molecular data suggests chimps and human are close relatives
Human evolutionary history
other Old World
gibbons orang gorilla chimps human
monkeys
many unique traits
similarities in teeth,
skull, genitals
brow ridge
loss of some hair
skull elongation
upright posture
loss of tail
increased brain size
Humans’ closest living relatives are chimpanzees
• shared derived traits: morphological: skull, teeth, genitals
behavioral: hunting, tool use, social behaviors
?
Millions of years ago
Australopithecus
robustus
Homo
ergaster
Australopithecus
africanus
Homo
sapiens
Australopithecus
afarensis
Homo
neanderthalensis
Homo
erectus
Australopithecus
anamensis
Australopithecus
boisei
Homo
habilis
Ardipithecus
ramidus
Ardipithecus
ramidus kadabba
Orrorin tugenesis
Figure 19.3
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• The earliest hominids were a diverse group
– Various species of Australopithecus date from
about 4 to 1 million years ago
– Our own species, Homo sapiens, is the only
hominid that has not become extinct
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19.4 Upright posture evolved well before our
enlarged brain
• Australopithecines
had relatively small
brains
– This indicates that
bipedalism preceded
the evolution of the
enlarged brain
– Bipedalism is a basic
human trait
Figure 19.4
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19.5 Homo and the evolution of larger brains
• Homo habilis, an early African hominid,
coexisted with some of the australopithecines
– They had larger brains and made simple tools
– They may also have given rise to the more
advanced Homo erectus
• Homo erectus spread out of Africa over most of
the Old World
– They eventually gave rise to Homo sapiens
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19.6 When and where did modern humans arise?
• One of the regional descendents of H. erectus
was the stocky and muscular Neanderthals
– They lived throughout Europe from about
200,000 to 40,000 years ago
Figure 19.6
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A brief history of human
brains
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Neandertals - large brains 200,000 years ago
Modern homo sapiens (and their brains) evolved ~
100,000 years ago in africa
Most toolmaking came tens of thousands of years later
Agriculture and the rapid growth of human
populations came 90,000 years later
• Some paleoanthropologists think that modern
humans arose from the regionally diverse
populations of archaic Homo sapiens in Africa,
Europe, and Asia
• Others believe that modern Homo sapiens
came from a second group in Africa
– This group arose around 100,00 years ago
– They migrated out of Africa
– They replaced regional populations of archaic
peoples
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OUR CULTURAL HISTORY AND ITS
CONSEQUENCES
19.7 Culture gives us enormous power to change
our environment
• Major milestones in the evolution of Homo
sapiens are the evolution of
– an erect stance
– a large brain
– a prolonged period of parental care
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Evolution
Evolution
Evolution of mind
 The
mind evolved just like the rest of the
body.

The principle is clear, but the details are
highly contentious
 What
might have been a driving force for
human minds?
Evolution
Evolution
Evolution
Evolution
Evolution
The Mating Mind
Geoffrey Miller
Why do we have
big brains?
Evolution of the brain

Brain is expensive


Evolution requires you to pay your way as you
go;
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
brain energy use as a percent of resting body usage
 most vertebrates: 2 to 8%
 apes and some monkeys: 13%
 Humans: 20%
no investment for 50,000 years in the future
What was the brain used for in the mean time?
Forms of Darwinian Selection
 Natural
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"nature red in tooth and claw"
competition for food and for staying alive
 Sexual

selection
selection
Competition for mates
Sexual Selection

Female mate selection
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
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asymmetry of costs lead to male display and female
selection
male birds generally have the plumage
male humans have orgasm relatively easily, females less
easily
 Females are choosing
but also male selection in humans - why?


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hidden estrous requires multiple copulations
male investment in childrearing??
or just ongoing courtship
The Handicap Principle
 Handicap’s
provide useful signalsthat
the male is fit

Handicaps in human
 Aside:
the immorality of handcap
 Sexual selection causes runaway "fads"

peacock's feathers
Advertising fitness
 Fitness

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
Genetic quality
Health and nutrition
Sports

what do you win? - status
 Conspicuous
consumption
 Conspicuous generosity

not kinship or reciprocal altruism
External Phenotype

Genes for

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
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spiders web
beavers nest
Bowerbird’s bowers
Human handaxes?
Human art?
Bower Birds
Art as sexual selection?

We like art because we find it beautiful and
fullfilling

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
Clothes, jewlery, body paint



long before European cave paintings of 30,000
years ago
More common for males
artist


we like eating good food because it tastes good
why?
if asked why they do it, might not say it is for sex
Art requires male brains to produce and
female to appreciate/select)
Courtship in the
pleistocene - and now

meat hunting

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sustinance?

but not efficient to hunt big animals
buying sexual favors?

but mostly not directed to potential maies
display of fitness
 end up giving most of it away
assortive mating
giving of flowers or champagne

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brings pleasure not usefullness. - but why
pleasure?
certainly not a "fair exchange" for a prostitute
Hot vs. Cold choosers
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Cold
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Hot
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derives pleasure (curiosity, warmth, happiness, awe, lust,
adoration)
pick mate that makes you feel best
Cold and hot appears to give identical behavior

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hardwired algorithm for choosing a good mate
how would you know if the computer is happy?
but hot provides a much more general mechanism

happiness can result from good food, good nest, thriving
children ...
Subliminal semantic categorization a) LVF b) RVF
W. W. Norton
Prior exposure to one of top
two pictures biases perception
of character of neutral boy
W. W. Norton
Dissociation between priming and explicit memory
W. W. Norton
Cotterill, R.M.J. (1997). On the neural correlates of consciousness. Jpn. J. Cogn. Sci. 4:31-34.
“The chicken claw goes
with chicken and you
need a shovel to clean out
the chicken shed.”
Is there a left frontal
interpreter or scenario
generator?
Efron’s simultaneity
W. W. Norton
W. W. Norton
Evolution
1.
2.
3.
4.
Temporal lobe epilepsy and religious visions
Ramachandran’s experiments with TLE
Historical figures Moses, St. Paul, Ellen G. White
Heritability (.45)
W. W. Norton
W. W. Norton
W. W. Norton
W. W. Norton
W. W. Norton
W. W. Norton
W. W. Norton