MS130 - Biology
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Pete Markiewicz
Week 05
Web Links - Human Evolution
| JOKO HOMO (DEVO, 1978) -
DEVO stands for "De EVolution OF mankind |
They tell us that
We lost our tails
Evolving up
From little snails
I say it’s all
Just wind in sails
Are we not men?
We are devo! |
We’re pinheads now
We are not whole
We’re pinheads all
Jocko homo
Are we not men?
D-e-v-o |
Monkey men all
In business suit
Teachers and critics
All dance the poot
Are we not men?
We are devo!
Are we not men?
D-e-v-o |
God made man
But he used the monkey to do it
Apes in the plan
We’re all here to prove it
I can walk like an ape
Talk like an ape
I can do what a monkey can do
God made man
But a monkey supplied the glue
We must repeat
O.k. let’s go!
|
The Darwin awards (people who remove
themselves from reproduction by idiot, lethal behavior)
http://www.darwinawards.com/
The 2006 Idiot awards?
http://chocolateandraspberries.blogspot.com/2006/12/idiot-awards-for-2006.html
WHAT ARE PEOPLE?
TAKE-HOME LESSON
FOR TODAY - you're an animal
Monkey's voice just as good as
a human
for newborn babies
http://www.livescience.com/humanbiology/060217_baby_listen.html
You are also a...
- Primate - tree-dwelling, fingernails, binocular color vision,
fruit-eating, large brains, highly social, grooming, nose-picking, several thousand species,
appeared during Age of Dinosaurs (70 million years ago)
- Great Ape - arms adapted for brachiating (swinging in trees), very large
brain, 4 surviving species (Chimpanzee, Gorilla, Gibbon, Orangs)
http://www.umanitoba.ca/anthropology/courses/121/primatology/pongid.html
- Hominid - upright posture on ground, tool-using, primitive,
generalized body form, 1 surviving species (Homo
sapiens)
PRIMATE EVOLUTION
PRECURSORS TO HUMANITY
Tool use
 |
 |
 |
 |
Chimpanzee tool use (modified twigs for termites, hammer/anvil
stones for cracking nuts)
|
Bonobo tool use (modified twigs for termites, hammer/anvil stones
for cracking nuts) |
Capuchin (New World monkey, independently
evolved tool use, sticks to dig up roots, hammer/anvil to crush
nuts, stones carried to "work" site |
Gorilla
in the Republic of Congo using a stick to test a pool of water for depth
before wading into it (looks like the water is cold). |
Language
Culture
Emotions
HUMAN EVOLUTION
Environmental forces driving human evolution
- The "grassland->savannah" effect
- Climate change in Africa - 7-2
million years ago, destroyed the unbroken "Eden" lowland rainforest,
converted to it to grasslands (savannah)
- Savannah split into a "mosaic" of
micro-climates, ranging from desert to lake shoreline
- Maximum diversity of animal life (more
predators!)
- Movement from forest to grassland as Africa dried out in late
Pliocene
(5-10 million years ago) caused shift from ape locomotion to long-distance,
biped running (apes walk but can't run, human running endurance is more like
wolves)
- Running ability key to human body form
"...traits such as a small ridge at the base of our skulls,
shoulders decoupled from our heads, an extensive series of springy tendons
along the back of our legs and feet, and well-defined buttocks...over
long distances we can outrun dogs and give horses a run for the money...running
evolved in order for our direct ancestors to compete with other carnivores
for access to the protein needed to grow the big brains that we enjoy today."
http://www.astrobio.net/news/article1307.html
- Grassland predators (particularly leopards,
but 10 species of big cats instead of 4) and shoreline killers (hippos, 30
foot crocs)
- Switch from vegetarian to mixed meat/plant diet
(especially fat from marrow of dead animals) provided better nutrition
- Feast/famine food gathering
encouraged development of body fat reserves
- The "aquatic" or "shoreline"
effect
- Diet of fish and shellfish
eaten by early human ancestors (e.g. Homo habilis) living near Lake Victoria
and other African lakes (completely unlike other apes)
- Shoreline diet provided "brain-specific"
nutrients like docosahexaenoic acid (DHA).
and iodine allowing human brains to grow larger
than other apes
- Love that baby fat - effect of shore
diet on early human brain size
"...The shores (of African lakes) gave us food security and higher
nutrient density. My hypothesis is that to permit the brain to start to
increase in size, the fittest early humans were those with the fattest
infants," says Dr. Cunnane, author of the book Survival of the Fattest,
published in 2005..."
http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=1875&mode=thread&order=0&thold=0
- The "giant-brained baby" effect
- Increasing size of infant skull,
brain size - major effects of women's bodies, makes human pregnancy
extremely difficult compared to most other animals
- Need to shed extra body heat coming
from baby's brain during pregnancy may have resulted in hairlessness.
- Increasing care required by helpless, slow-growing infant
results in monogamy, families, evolution of "old age" (see below), instead
of harem-style sexual organization (one parent not enough to raise infant)
- The "sexual selection" effect
- Sexual selection - animals are "already dressed",
body form, color, ornamentation selected by mating
choices of opposite sex
- Human body betrays clear signs of
sexual selection
- Types of sexual selection
- Female selects male body form (typical of
most mammals, birds, results in male "peacock" competing with other males
for mates, drab females)
- Male selects female body form (VERY unusual in mammals,
birds, results in female "peacock" competing with other females for mates)
- The "killer ape" effect (now thought
unlikely)
- Raymond Dart postulated that a line of
"killer apes" branched off from nonviolent primate background to create
humanity
- Popularized by Robert Audrey in 1950s book
African Genesis and Desmond Morris in 1960s book The Naked Ape
and 2001: A Space Odyssey
- Humanity evolved through ruthless
competition using ever-better tools with other early humans
- Cannibalism, extermination of other humans
"natural" to our species
- Problems with model
- Common chimpanzees are already "killer
apes" to some extent (not realized until 1970s)
- Bonobos DO NOT show murderous
inter-group aggression (instead, collective sex)
- Early humans were scavengers of animal
kills, rather than hunters
SEQUENCE OF HUMAN EVOLUTION
OUT OF AFRICA
- Most
scientists believe that humanity rose in Africa (Ethiopia/Kenya region), and all subsequent
evolutionary leaps to new human species ONLY happened in Africa and spread to the rest of the world.
- Increasingly supported by genetic analysis of
modern humans and fossil human DNA
- New humans evolving in Africa displaced
(rather than interbreeding with) earlier humans as the spread outward from
their origin.
- Population as low as 5,000 provided common
ancestor of all humanity
- Alternate "multiregional" hypothesis has
fallen into disfavor
The region of the world in which humanity
evolved
The landscape where humanity evolved
ERAS OF HUMAN EVOLUTION
Australopithecus era
- 7 million years ago - First upright hominids appeared
in Africa ~ - NO BRAIN
SIZE INCREASE (450grams).
The body came before the brain...
- Footprints from the "mystery era"
- 2-7 million years ago - a variety of upright-walking hominid
species present
- Males much larger than females, likely had harem sexual
structure,
- NO BRAIN SIZE INCREASE (450 grams),
- Legs adapted for walking, but arms still
allow tree-climbing
- 2.5 million years ago - Earth begins
to cool rapidly until it enters our current Ice Age 1 million years ago
Homo habilis - "handy man"
Homo erectus - "a quantum jump"
- Appears 1.8 million years ago - another 50% jump in
brain size, better tools adapted for cutting meat off bones, body below neck
adapted for running, nearly the same as modern humans. Scavenged kills but
probably not a strong hunter. Strong
evidence for ritual or 'eatin cannibalism, hints of religious/spiritual
interest.
- Computerized analysis of skull confirms
unique structure to "hobbit" brain (in other words, the dwarfed Homo
erectus kept evolving in its own direction during its isolation from
Homo sapiens)
http://www.livescience.com/humanbiology/070129_hobbit_microceph.html
Homo Antecessor
- 1 million years ago - advanced Homo
erectus, precursor to Homo sapiens and Homo neanderthalis. Strong
evidence for ritual or 'eatin cannibalism.
- 200,000 years ago - "archaic" Homo sapiens - another 100% jump in
brain size to modern level, but skull shape is very different from modern human
skull, brain lies on back of skull rather than over forehead.
- 130,000 - 40,000 years - Neanderthals (Homo neanderthalis) - Another human species, adapted
to Ice Age Europe. "Bruiser" body like Eskimos today, larger brain than
modern humans, huge nose, men and women equally strong, adapted to kill prey
at close range, mammoth-hunters, burial,
care for aged, "bear cult" religion, no sign of visual art (controversy)
- Human and Neanderthal skulls compared (MOVIES of transformation)
http://www.ifi.unizh.ch/staff/zolli/CAP/comparingNeand.htm
- Adult Neanderthal skull
http://www.modelspecimens.com/HomePage_files/image005.jpg
- Neanderthal stories -
http://www.channel4.com/history/microsites/N/neanderthal/tv_programme/highlights.htmlb
- Neanderthal woman (reconstruction)
http://biology.plosjournals.org/perlserv/?request=slideshow&type=figure&doi=10.1371/journal.pbio.0020449
- Example of Neanderthal art - rock made to
look as if it had eyes
http://news.bbc.co.uk/2/hi/science/nature/3256228.stm
- Other forms of Neanderthal art (disputed)
http://www.neanderthalerart.com/index.html
Homo sapiens
- 130,000 - 12,000 years - Homo sapiens sapiens (you) - Adapted to tropics, appeared in
Africa, replaced or destroyed Neanderthals and earlier human species as they
went. Hunter-gatherer, large brains, art, culture and civilization. The
first human in which all modern features (advanced tools, cave art, jewelry)
are present.
- Sea cave yields ancient signs
(165,000 years ago) of modern behavior
The new discoveries bolster the proposition that modern-human
behavior developed gradually, starting perhaps 285,000 years ago, remark
anthropologists Sally McBrearty of the University of Connecticut in
Storrs and Chris Stringer of the Natural History Museum in London in an
accompanying editorial. The earliest evidence of red-pigment use comes
from that time, prior to the evolution of anatomically modern humans....Marean's
finds at Pinnacle Point suggest that an ancient reliance on seafood "may
have been one critical factor in the expansion of Homo sapiens
out of Africa and along coastal routes to the east," Henshilwood says.
http://www.sciencenews.org/articles/20071020/fob2.asp
- "Mitochondrial Eve" & "Y chromosome Adam" - analysis of genetics of
modern humans indicates that modern humans may have come
from a tiny population (< 2000 individuals) in East Africa (Ethiopia, Rift
Valley area). about 160,000 years ago.
http://www.nationmaster.com/encyclopedia/Mitochondrial-Eve
- Homo sapiens split into
- Homo sapiens neanderthalis -
Neanderthals, left africa 130,000 years ago, likely displaced by H.
sapiens sapiens 40,000 years ago
- Homo sapiens sapiens - modern
humans, left Africa ~50,000 years ago
(Modern) humans versus Neanderthals: game over earlier than thought
http://www.livescience.com/othernews/060222_neanderthals.html
- Map of early human migrations
http://commons.wikimedia.org/wiki/Image:Human_mtDNA_migration.png
- Another, more complex map
http://partners.nytimes.com/library/national/science/050200sci-genetics-evolution.1.GIF.html
- Tracing yourself in the human tree
http://www.guardian.co.uk/life/feature/story/0,,1471351,00.html
- Sample Cro Magnon skull (~45,000 years
old)
http://www.pangeainstitute.us/photogallery/displayimage.php?album=18&pos=39
- Sophistication in Stone-Age cultures
(circa 50,000-70,000 BC) - modern Orchron hunter-gatherer (reindeer
hunter)
http://donsmaps.com/clickphotos/reindeerman.jpg
THE ORIGIN OF ART
- Oldest human art is jewelry from ~70,000
years ago
http://news.nationalgeographic.com/news/2004/04/0415_040415_oldestjewelry.html
http://www.sciam.com/article.cfm?articleID=000084C2-188C-107F-988C83414B7F0000
- "Cave art" - 45,000 - 10,000 years ago
(example shown for highly skilled artists)
http://www.culture.gouv.fr/culture/arcnat/chauvet/en/index.html
Examples from Chavuet cave, France, 30,000
BC.
THERE HAVE NEVER BEEN ANY "CAVEMEN"
People did not live in caves but under
overhangs and in the mouths of caves. Cave art was preserved by the cave's
constant environment, while other art made by these people has disintegrated
over time and weather.
- "Venus" sculpture from Ice age
(~30,000 years ago)
http://encarta.msn.com/media_461517441/Venus_of_Willendorf.html
(a totem, probably showing the ritual outfit girls wore during puberty
"coming of age" dance)
- Ancient cave art was mixed
http://www.livescience.com/history/060214_cave_art.html
"...rather than being the special province of a
narrow group of shamans or seers, as many anthropologists had supposed,
Paleolithic art was made by adults and children of both genders and
depicts a primitive incarnation of the contemporary family..."
The Nature of Paleolithic Art, by R. Dale Guthrie
http://www.amazon.com/gp/product/0226311260/sr=8-1/qid=1140125957/ref=pd_bbs_1/103-3475271-0015808?%5Fencoding=UTF8
- People drew hand outlines to
sign their work, so we can tell age, sex of artist. Art is 80% male, 20% female,
some children.
- Types of cave art
- Some cave art features beautifully
drawn paintings - religious/spiritual significance
- Less-skilled "ordinary" art more
common
- And most of the drawings
are unskilled, crude male, teen-age graffiti!
- Lots of crudely rendered hunting
scenes with excessive graphic violence
- Crudely drawn sex acts with
female genitals pictured in wrong position
- "The people in the art are
predominantly women, and not a single one has any clothes
on."
- The walls were also
decorated with graphic depictions of genitalia.
- Graffiti-style art is found
deep in the caves, while the "good art" is near the cave mouth
(from "The Nature of Paleolithic Art" by Dale
Gutherie)
THE ORIGIN OF CIVILIZATION ("THE
LONG, HOT SUMMER" OF THE HOLOCENE)
The above chart from The Nature of Paleolithic art goes from 0-60,000
years, about the time that modern Homo sapiens entered Europe and Asia from
Africa. The final Ice Age begins ending about 18,000 years ago, and after a
short cooling era 12,000 years ago, the a sudden jump of global warming is seen.
More important, the climate becomes very stable. Agriculture begins at the same
moment the climate warms and stabilizes 12,000 years ago. The dawn of
civilization may be tied to the appearance of the "long, hot summer" of the
Holocene.
A close-up of the end of the Pleistocene and the beginning of the Holocene -
civilization appeared "after the ice" and was tied to a dramatic episode of
global warming. From After The Ice: A Global Human History by Steven
Mithen (2004), Harvard University Press.
- Rise of agriculture and civilization 12,000 years ago
- "Neolithic" era
- Art is frequently LESS REALISTIC - more
symbolic
- Jericho, the first city in the world -
10,000 years ago, built at start of Holocene
http://www.crystalinks.com/jericho.html
http://classics.unc.edu/courses/clar047/NeolPcs.html
 |
 |
| Reconstruction of Jericho, 9,000 years ago, showing defensive
wall. There was also a building which appears to have been an inn
for travelers, making it more than a village. |
Plastered human skull from burial during proto-Neolithic period,
~9,000 years ago |
- Bronze age - 6,000 years ago (first metals)
- Civilization flourishes in the "long hot
summer" of the Holocene between Ice Ages.
- The Ice Ages will return in a few thousand years if we
stop global warming.
HOW HUMANS ARE UNIQUE
- Upright posture (all the time, major pelvic restructuring, arms shorter
than legs, toes no longer opposable)
- Ability to jog/run long distances in open
daylight, wear down prey like wolves, instead of pounce like big cats (nuchal
ridge keeps skull from bobbing, pelvis, body-wide sweat glands)
http://www.livescience.com/humanbiology/041117_running_humans.html (Good
Pictures!)
- Lengthening of thumb
- Neoteny
- Adult human skull similar to infant chimpanzee
- Women show greater neoteny than men (reduces male->female aggression)
- Bodily hair becomes ultrafine (doesn't disappear, people have as much hair
as other apes, may be related to adoption of clothing, need to lose heat in
grasslands.
- Long hair on head protects brain from heat (out in open sun)
- Denser, longer-growing head hair in females helps differentiate sex
- Older males tend to go bald, females and males go "grey" (a way of
identifying elders)
- Sweat glands over entire body (like horses, unlike other apes)
- Crying salt tears (may be related to aquatic stage)
- Body weakness relative to other apes (tools?)
- Loss of canine teeth, very large molars (switch to tuber diet and tools)
- Flattened muzzle, less bone and muscle in skull
- Sophisticated tool use (tools are carried around, saved, used in
groups)
- "Circle of Willis" supporting enough blood flow to a massive brain
- "Diving reflex" (human ancestors may have had a shellfish/fish eating
stage)
- Eyes have visible whites (important to know where everyone else is
looking)
- Fat layers in defined positions under skin
- May be related to aquatic stage
- Resistance to famine conditions
- Women have a double layer
- Change of sexual system to "serial monogamy" - the family is a
basis for human society. In common chimps, it is the "troop" of males plus
isolated females. In bonobos, it is female-female bonding plus male-female
alliances (closer to human-style family structure)
- Private sex (chimp, great ape sex is public, ours is private, why we have "porn")
- Sexual "flush" in men and women during sexual arousal (replaces lack of
sexual skin?)
http://www.bettersex.com/sexdata/term.asp?termid=Sex_Flush&cookie%5Ftest=1
- Prolonged youth (appeared between Homo erectus and Homo
sapiens)
- Old age as a distinct life stage (cultural memory, aid in care of children's children)
- Language
- Voice box moved to different position on throat
- World described symbolically at a very high level relative to other
animals
NEOTENY IN HUMAN EVOLUTION
- Humans have the skull and brain of a fetal ape
- Lest "robust" body - smaller, weaker than
earlier human ancestory (child-like)
- Women show greater neoteny than men (less "ape-like")
- Human vs. capuchin monkey -
http://ourworld.compuserve.com/homepages/dp5/skulls.jpg
 |
 |
| Comparison of human infant and human adult to
Capuchin monkey infant and adult skulls. |
Changes in human versus chimpanzee skulls from infant to adult
form - chimpanzee on left, human on right. |
"Aquatic ape" theory
SEXUAL SYSTEMS IN APES AND HUMANS
- Gibbons, marmosets, tamarins - strict
monogamy
- Marmoset monkeys monogamy similar to humans (like gibbons, unlike chimps, gorillas, orangs)
"...The marmoset fMRI findings add strong weight to the mounting evidence
that, when faced with a novel, sexually attractive and receptive female, males
in monogamous species aren't necessarily just acting on some primal urge to
procreate, without a second thought. Rather, they exhibit highly organized,
complex neural processes..."
http://www.sciencedaily.com/releases/2004/01/040130080948.htm
- Gorillas - harems, males 2x size of females, males try enticing females
from each other
http://yahooligans.yahoo.com/content/animals/species/9781.html
- Orangs - extremely rare sex, no monogamy or harems
http://www.whozoo.org/students/chrngu/orangs.htm
- Common chimpanzee
http://pin.primate.wisc.edu/factsheets/entry/bonobo/behav
- "Doggie style" sex exclusively
- Cyclical appearance of "sexual skin" on
female when fertile
- Sex is about reproduction
- Ultra-aggressive males harass females, practice infanticide
- Females leave home group on puberty
- Solitary females don't form bonds with males,
weak bonds with other females
- Excitable, violent (e.g. organized "murder" of scapegoat chimps)
- Tool use, tool types differs with group (cultural)
- Bonobo chimpanzee
http://pin.primate.wisc.edu/factsheets/entry/bonobo/behav
- Frontal sex in, orgasms in male and female, sex for fun, stress reduction,
Females will bribe males for sex
- Lots of same-sex action (female group gropes)
- Constant "sexual skin" and sexual activity makes periods of
fertility unknown to others
- Infanticide almost unknown - strong protective female-female bonding
protects their children
- Females leave their "home" group on puberty (prevents inbreeding)
- Males and females form "alliances" (proto-family structure)
- Parenting of orphaned infants
- Females may become troop leaders
- Tool use, differs with group (cultural)
- Why bonobos are so behaviorally different from common chimpanzees (food
availability?)
http://www.pbs.org/wgbh/evolution/library/07/3/l_073_03.html
- Human sexual systems
- Serial monogamy
- Occasional "fooling around"
- Same-sex relationships
- Adopted by all males/females in
'unusual' circumstances
- Exclusive ~7% male, ~3% female
- Harems for
powerful males
-
http://www.psy.plym.ac.uk/year3/psy364sexual-selection/psy364sexual-selection.htm
-
http://human-nature.com/ep/articles/ep026685.html
- Infidelity - about 20% of the time
- Sex with children - seen in both
genders, but situations in which it arises differ
- Rape - rare "outsider" males
rejected by group, also seen during violent conflicts between social
groups
- Bestiality - "In the 1940s, Kinsey asked twenty thousand Americans
about their sexual behavior, and found that 8 percent of males and 3.5
percent of females stated that they had, at some time, had a sexual
encounter with an animal."
GENDER DIFFERENCES IN HOMO SAPIENS
Humans display much more sexual dimorphism
than either chimpanzee species
Origins:
- Different roles played by each gender during hunter-gatherer era of human evolution
- Sexual selection
1. Gender differences based on "primordial" roles during hunter-gatherer
stage of human evolution
- Women - pregnancy and birth, infant care during first few years
of life, language acquisition by infant, foraging for low-density food
- Men - infant care, supplemental care and protection of females
with children, long-range foraging/hunting, defense of group
- Differences between male and female brains (good chart of tests
showing differences)
http://www.sciam.com/article.cfm?articleID=00018E9D-879D-1D06-8E49809EC588EEDF
- Male brains are optimized for
long-range hunting, females for short-range, complex gathering tasks
- Spatial maps, virtual objects, maps, math reasoning, throwing
objects at targets (males excel)
- Pattern-matching, language, reading, math calculation, precision
manual tasks, memory (females excel)
- Females have larger frontal lobes (more
"executive function" for decision-making)
- Pain suppression (males have less pain,
fewer chronic pain problems, females has more chronic pain, lower pain
thresholds, more easily "hooked" on addictive pain-suppressing drugs)
- Mental health (males are more commonly
austic, females suffer depression at twice the frequency of men)
- More information on gender-specific
brain differences
http://www.independent.co.uk/news/science/womens-brains-uareu-different-from-mens-ndash-and-heres-scientific-proof-870849.html
Gender-based evolutionary roles
Males - must find mate capable of
surviving pregnancy, bearing and raising helpless,
slow-growing infants who require massive amounts of care - and don't sleep
around and make them help raise children who have different fathers.
Males are take a bigger risk in future
reproductive success if they are monogamous, so fidelity is important.
Females - must find mate who will devote
resources to her and her children rather than other women - and who don't sleep around and expend their
resources on babies made with other women.
2. Sexual selection - traits are selected, not because of
environmental or competitive pressures, but for their attractiveness to the
opposite sex.
Ultra-demanding infants and children have driven sexual selection in
both sexes in humans. Both sexes are required to raise children in
hunter-gatherer societies. Therefore, both males and females must prove how "healthy" they are to the
opposite sex and capable of their own evolutionary role to get the required investment
(e.g. a mate) to raise children.
Monogamous
bonds are part of human biology, and are essential to raising children up
until the beginning of industrial society (300 years)
However,
both males and females seek sex outside of pair bond to "hedge their bets" on
reproduction.
- Male body is determined by female choice (typical in most mammals and
birds, great apes)
- Female body is determined by male choice (VERY rare in mammals,
not seen in other great apes)
- Humans as a "weird" species - sexual selection of women by men
(David Brin) http://www.davidbrin.com/neotenyarticle1.html
SEX = POWER
Charts from The Nature Of Paleolithic
Art, R. Dale Gutherie (2005), University of Chicago Press.
SEXUAL SELECTION IN HUMANS
From a great discussion of human sexuality in evolution at:
http://www.dhushara.com/paradoxhtm/homo.htm
One gender selects the other based on...
- Superior genes (as shown by body,
behavior)
- Health, coordination
- Confidence in social situations
- Harass, threaten, dominate members of your gender
- Assert your dominance position in the "pecking order"
- Ability to "take risks" because of
superior survival skills
- Especially important in adolesence, since
younger individuals can't match social power of older ones
- Social power
- Money, influence, "magnetic personality"
- Plastic surgery exaggerates major sexual display signals
- Artists exaggerate sexual display in images, movies, games
Sexually-selected features common to both
genders
http://www.livescience.com/humanbiology/060213_attraction_rules.html
Body symmetry
Correct waist/hip ratios (WHR)
"...People in the ideal hip-ratio
range, regardless of weight, are less susceptible to disease such as
cardiovascular disorders, cancer, and diabetes,
studies have shown...
In other words, physical
beauty really does indicate superior genes!
Lips
- Inside of mouth turned out for form red lips (redder in women,
another sexual signal?)
Fidelity
- Human children take too many resources for
one parent to raise (like birds, unlike most other mammals)
- Two or more parent (i.e. grandparents,
brothers and sisters) are needed to raise human children
- "Fooling around" means your mate wastes
resources on unrelated children (so yours get less)
|
SEXUAL SELECTION FOR BODY TYPE - HUMAN MALE
Should be ultra colorful, like mandrill, relative to females
Pixyland.org - why do you find this STRAIGHT guy so shocking?
http://www.pixyland.org
Male models (idealized face/body) -
http://www.anti-models.nl/index2.php?type=men&subtype=fashion
- 15% larger than female (male and female chimps are only 5% different)
- Physical aggression, rough and tumble" competitive play (sports)
- X-treme risk-taking with possibility of
injury or death (especially younger males, serves to attract females away
from older men)
- Neoteny relative to great apes
- Flat face, mildly sloping forehead, (no muzzle)
- Reduced facial, body hair
- Reduced muzzle
- "Bad" men look more "apelike"
- Apelike relative to human females
- Straight eyebrows on strong eyebrow ridges, eyes deep-set
- Small eyes relative to skull, narrow (why "evil" men have slit beady
eyes)
- Facial hair (variable)
- Larger lower face relative to skull
(bigger chin)
- Distance between nose, lips longer than females (a bit of muzzle)
- Long torso, short legs
- Low-pitched voice
- One layer of body fat (other apes don't have any)
- Waist/hip ratio (WHR) of 0.8-1.0 (proves correct amount of testosterone is being produced by his body)
- More obvious hair on body, head hair is
short
- Lips turned out, straight, thin (not rounded)
- Hollow cheekbones (flatter than females, less fat on face)
- Narrow hips (don't need to have babies)
- Extremely thick
penis but average testicles relative to other apes.
- Penis not for sexual display (otherwise it would be bright blue,
muscular, have wattles, etc.)
- Chimps have muscular penises used for
everyday display, humans have hydrostatic penises with little conscious
control
- Testicles indicate moderate promiscuity
among females, (sperm-sperm competition in female's body significant)
- Foreskin makes entry of thick penis easier, less painful for females
http://www.cirp.org/library/anatomy/taves1/
- 3 times weaker than chimps, orangs (Muscles of human males puff with water, make them
look stronger than they really are).
- Navigate environment primarily by internal 3D maps
CHOOSING A MATE - HUMAN MALES
- Discriminate mates visually based on
- Body fat percentage (breasts),
- "Childlike" (non-apelike)
features (large eyes, small eyebrows, small lower face)
- Facial and body symmetry (the more
symmetrical, the more attractive)
- Fat under skin smoothing muscle outlines ("curves"),
- Wide
hips/buttocks, narrow shoulders,
- Red lips (women's lips become redder at ovulation)
- Body odor
- Males respond more to visual stimuli than women
http://www.sciencedaily.com/releases/2004/03/040316072953.htm
- Women smell (and look) best to men at
particular times of the month
http://www.livescience.com/humanbiology/060118_armpit_odor.html
- More on human smell
http://www.timesonline.co.uk/article/0,,8123-1969987,00.html
- Attraction to underage females (virginity = no existing child to sap
energy away from new one, plus easier to dominate and control her sexual
behavior)
- Relatively monogamous, but will split attention between "steady"
mate and a set of transient outside "relationships", harem systems also
exist for powerful males (pimping)
- Paternity is important to men (consequence of stable, long-term monogamy)
- Provide for children physically and
psychologically (not true for other great apes)
"... But these designer children (women who deliberately
chose to be single mothers) suffer just like children without fathers have
always suffered. Daughters lack that first male to measure men by, and they
are more likely to engage in destructive sexual relations at earlier ages
than girls raised with fathers. Sons lack a man to model themselves after,
and often never learn the discipline to control male aggressiveness. Such
sons and daughters never see how problems can be worked out within a loving
marriage, and descend into the psychological spiral that leads to a
succession of failed relationships..."
http://www.washtimes.com/op-ed/20051207-104212-1732r.htm
- Greatly reduced fertility during old age (sperm present, but
fertility drops like a stone after age 40)
- Trade resources for sex (prostitution,
common in humans and other male mammals)
- Trade sex for resource (common
in same-sex prostitution, less common in heterosexual, but this is partly
culture-dependent)
- Rape (not seen in chimps, possibly in orangs)
- Fear of rape in female soldiers in Iraq leads to dehydration deaths
"...several women had died of dehydration because they refused
to drink liquids late in the day. They were afraid of being assaulted or
even raped by male soldiers if they had to use the women's latrine after
dark...".
http://www.alternet.org/waroniraq/31584/
- "Stealing wives" - attack other groups of people, kill
the men, grab
the women and take them home, and have your own women "initiate" them into
the group
- Homosexuality
ATTRACTING A MATE - HUMAN MALE
- Sexual "swagger"
- Dancing, singing (body display, no parasites, good genetic
"rendering", proof of coordination)
- Flirting direct, "dominant"
stares
- Physical strength demonstrations
- Scars, physical - the sign of a "survivor" of male-male
conflicts
- Scars, emotional - "moody brooder"
survivors with soulful eyes
http://www.fametracker.com/2_stars_1_slot/caviezel_crudup.shtml
- Risk-taking (younger male's
compensation for lack of material resources)
- Demonstration of material wealth (the male's compensation for
pregnancy, mostly for older men)
- Enhance body via jewelry (e.g. fancy tennis shoes)
- Flaunt a pre-existing harem
- Dominance over other males
- Dancing, singing (body display, no parasites, good genetic "rendering", proof of coordination)
- Non-lethal fights - demonstrate who's the alpha male
(sports, sing-off, telling jokes)
- Deadly combat with other males
- Scared body an attractive feature to many females
- In "traditional" human societies, up to 25% of young men are murdered by
other men
- Older men are attractive to women
because they've survived combat and are more likely to have captured
resources needed for parenting)
- Non-aggressive behavior
- Good with kids - males are important in human child's psychological development
- "Pain behind those angel eyes" - inspires maternal
response
SEXUAL SELECTION FOR BODY TYPE - HUMAN FEMALE
http://employees.csbsju.edu/lmealey/hotspots/Chapter13.htm
Because the unusual sexual pattern in humans (males selecting females) an
alien from a more "typical" species would miss-identify women as men, and vice
versa.
 |
 |
| Typical animal male "peacock" - gaudy, sexual selection by
females |
Typical animal female (pea-hen, compare to peacock) |
| |
|
 |
 |
| Women in peacock outfit - like male of "normal" species |
Expected look for human females (camoed, drab, out of sight) |
 |
 |
| Human females "want" to look like this. An alien from a "normal"
species might assume that this is the male of the human species |
Human females should "want" to look like this |
 |
 |
| MALE Mandrill |
FEMALE Mandrill |
 |
 |
| Males of most mammal/bird species are "peacocks" |
Uniquely human female "peacock" |
- Female models and actresses (idealized face/body) -
http://www.arnadal.no/film/actors/30female.htm
- Body size 15% smaller than males (greater difference than
chimpanzees, much less than "harem" species like gorillas and
baboons)
- Light bone structure (why osteoporosis is common in old age)
- Physically weak (50% or less the strength of men, 1/10 female
chimpanzee)
- Greater sensitivity to pain (and other
sensations)
http://www.livescience.com/humanbiology/051024_women_pain.html
- Reduced physical aggression (but not social aggression or dominance behavior)
- But not non-violent!
"...Ambroise, who wrote about the Third Crusade (1189-90) describes
how many of the women who took part in the crusaders' siege of the city Acre
attacked the Turks with huge knives, bringing back their severed heads in
triumph..."
- Neoteny (child-like) features more pronounced than males
- Flat face, vertical or domed forehead
- Large eyes relative to skull
- Arched eyebrows
- Little or no eyebrow ridge
- Smaller lower face and chin (growth
capped by estrogen)
- Rounded cheekbones
- No "sexual skin" (hides time of fertility)
- BUT lips become redder, body rounder during fertile peak of
monthly cycle
- Short distance between nose, lips (no muzzle)
- High-pitched voice
- Double layer of body fat (whiter skin, allows women to survive
famines while
pregnant)
- Wide hips (necessary for birth of large-brained baby, changes
walk cycle)
- Waist-hip ratio (WHR) of 0.67-1.18 -
demonstrates correct of estrogens is being produced by her body. Also, she
will have less difficulty getting pregnant
- Short torso, long legs (so women can walk at same pace as larger men)
- Extra fat on hips (makes them look wider than they really are)
- Permanent breasts (even larger than Bonobos)
- Longer head hair than males, no facial hair,
fine body hair
- Smoother skin, smaller pores (varies with monthly cycle)
- Rounded, full lips
(become redder during fertile period)
- Cheeks redder than men
(makeup used to
enhance, redness may indicate
fertility level)
- Small head relative to body (especially as height increases)
- No swollen genitals at time of maximum
fertility
- Allows attraction of monogamous
versus transient partner - a male constantly pay attention to her at all
times to have any hope of getting her pregnant
- Does not attract attention of local Alpha
male who keeps trying to form a harem
- Engage in sexual displays to attract
mates (EXTREMELY unusual for female mammals)
- X-treme menstruation
- Much more dramatic
than other mammals in bloodletting (may have evolved after human society
became very powerful)
- 28-day Lunar-synchronized (Chimps have
irregular 30 day cycle, Bonobos 60 day cycle)
- Synchronization of menstrual cycle when women live in close
quarters
- Synchronized births
- Forces men to hunt for meat when the
moon is bright ("Sex strike" trading sex for meat - Chris Knight)
- Navigate environment primarily by "waypoints" or "signposts"
CHOOSING A MATE - HUMAN FEMALES
Persistent sexual interest tied closely
to monthly cycle, plus orgasms (like bonobos)
http://www.cirp.org/library/anatomy/cold-mcgrath/
- Discriminate mates visually based on
- Obvious, visible muscles (but x-treme
body builder level)
- Muscle size of human males "pumped
up" with water via testosterone
- Low body fat
- "Vein-y arms"
- "Hardbody butt" - it provides a
fast check of overall body fat level (think of "plumber's crack)
- Body symmetry
- Women are pickier than
men about symmetrical male bodies
"...Interestingly, the male
preference for symmetric females was not as strong as that of the female
preference for symmetric males. This seems to confirm the theory that
women are pickier when selecting a mate, since they bear most of the
burden of raising a child..."
http://www.livescience.com/humanbiology/051221_dance_symmetry.html
- Correct WHR - Narrow hips/compact buttocks
- Face "halfway" between "female/child" and "ape" neoteny
- Too apelike - evil!
- Too childlike - whimp!
- Partial face similarity
- Looks nothing like me - not a good
partner, but possibly a roll in the hay
- Looks a little like me - awesome!
(somewhat similar genes make for greater compatibility)
- Looks like my brother - bad match! (unless I'm pregnant)
- "Soulful" (squinty) eyes
- Heavy straight eyebrows
- Protect eyes during deadly
male-male fights
- Power - sex isn't tied to social
power - it IS power
- Age = power
- Grey hair, "mature" behavior a turn-on
- Young men at disadvantage relative to older men
- "Risky" male behavior
- Proves survival skills
- A way for young males to compete with older ones
- Body odor
- Beauty is in the nose of the beholder (women smell men for value just like female rats)
http://www.newscientist.com/article.ns?id=dn7668
- Women seek out men with different smells = different immune
system to mate
- During pregnancy, women seek out males with the
same smells
(relatives?)
- Male sweat raises arousal of
heterosexual women
"...Cortisol levels in the women rose within about 15 minutes of
inhaling the (male hormone) androstadienone scent and remained elevated
for more than an hour, UC Berkeley researchers found. They also
discovered that blood pressure, heart rate and breathing increased, mood
improved and sexual arousal was boosted..."
http://www.pantagraph.com/articles/2007/02/14/wtf/doc45d25eeb27d66383665597.txt
- Why female circumcision ? - to prevent
female orgasms
- Relatively monogamous, but will split attention between
a "steady" mate and a set of
transient outside "relationships" about 22% of the time to "hedge bets" in children
- Promiscuous females drive evolution
of semen genes
- The size of men's testicles
compared to other great apes indicates they have to make more of the
stuff to compensate for women sleeping around
- Larger than gibbon (truly
monogamous) and Orang (mates very rarely) but much smaller than
common chimp and bonobo
http://www.sciencedaily.com/releases/2004/11/041108014158.htm
- Infidelity/Promiscuity - In
1940, 1 in 5 children had a different father from
their mother's husband in - in other words an infidelity rate of
about 20%...about the same as today.
- How your genes can make you stray - genetics of infidelity
http://news.independent.co.uk/uk/health_medical/article328600.ece
"..a study of 1,600 female twins and found that while
the normal likelihood of infidelity in women is 22 per cent, having an
identical twin who is unfaithful makes the likelihood 44 per cent. He
concludes that 40 per cent of our desire to cheat comes from the
genetic make-up we've inherited from our parents (chromosomes 3, 7 and
20, if you need to know the ones to blame) - meaning some people are
more susceptible to committing infidelity..."
- "...Burnham and Phelan also found that women who cheat are most
likely to
do so in the four days surrounding ovulation - the days of highest
fertility - and are less likely to use contraceptives with their
lovers than with their husbands. The idea that women may be
subconsciously driven to cheat in order to make babies is supported by
the recent finding that up to one in 25 British men are unknowingly
not the fathers of the children who call them daddy..."
- Women's marital bliss depends most
on male fidelity, plus being a "provider" (in other words, the
male is willing to provide the majority of resources)
"...the new research
determined that women whose husbands bring home more than 68 percent of
the bacon are the most content...'Regardless of what married women say
they believe about gender, they tend to have happier marriages when
their husband is a good provider - provided that he is also emotionally
engaged,' said W. Bradford Wilcox, a University of Virginia sociologist.
'I was very surprised to find that even egalitarian-minded women are
happier when their marriages are organized along more gendered
lines...'"
http://www.livescience.com/humanbiology/060314_happy_marriage.html
- Reduced (but still present) sex drive during pregnancy
- Trade sex for resources (prostitution, typical of most female mammals)
- Trade resources for sex (uncommon,
but never happens in most mammals, culture-dependent)
- Sex with children (usually their own)
- Infanticide - common in hunter-gatherer societies to lessen
burden on other children if birth control doesn't work
- Menopause - fertility ends, creates unique "third era" of life.
Allows older women to help their daughters and sons raise their children
- Homosexuality
- Facultative bisexuality in all females
- Not used for routine female-female bonding
(we're NOT like bonobos)
- Exclusive same-sex behavior occurs at a lower percentage (50%)
than men
- Bisexuality may be higher
ATTRACTING A MATE - HUMAN FEMALE
- Proof of strength (lesser), coordination, endurance, fertility,
virginity
- Oscillates between public "flaunting"
(which will bring in the alpha male) and more subtle cues (which attract a
monogamous partner)
- Sexual swagger
- Dancing, singing (body display, no parasites, good genetic "rendering", proof of coordination)
- Dominance over other females -
assures male that resources won't be stolen from his children by other
females)
- Flirting - lowering head and looking up at male (pseudo-submission)
- "I am available" body language
emphasizing fat deposits on breasts, buttocks
- "Throwing (usually longer) hair" during flirting, dancing,
esp. when most fertile
-
http://cas.bellarmine.edu/tietjen/Ethology/ethologyy_pix.htm (MOVIES,
scroll to bottom)
Example of spontaneous flirtation...
- Walk cycle "wiggle" - demonstrates wider hips, fat on hips
and breasts (it jiggles)
-
http://cas.bellarmine.edu/tietjen/Ethology/ethologyy_pix.htm (MOVIES,
scroll to bottom)
"...Under high estrogen levels (at peak of monthly cycle),
women's body movements are
slower and show a higher information content per time (essentially, "look at
me!")."
- "A survivor"- men prefer older, beautiful women over younger, less
attractive women
- Dominance over other females
- Non-lethal fights - instead determines female (and their children's)
access to males and group resources ("ins and outs" conflicts in grade
school)
- Women rate other women as "most
ugly" during fertile period of monthly cycle
http://www.newscientist.com/article.ns?id=dn4691
- Why are "girlfights" sexy to men? -
they demonstrate who's the (real) alpha
female
- Jewelry/clothing emphasizes body
features (oldest examples 70,000 years old)
- Proving maximum fertility
- High estrogen = female facial attractiveness
http://www.newscientist.com/article.ns?id=dn8251&feedId=online-news_rss20
- Arched eyebrows - angle of arch increases with increasing
estrogen
- Smooth skin - skin smoother,
reduced blemishes during fertile period (makeup)
- Red color - red lips, cheeks
imply peak of fertility
- Fake additional fat deposits (sufficient to survive pregnancy)
- J-Lo butt - enormous fat storage area
- Ideal shape spherical, merges with fat going down back of legs
- May form duplicate genital signal
replacing "sexual skin"
- Emphasis of breast size, shape
- Proves female got enough to eat
(good access to resources)
- Sufficient fat to survive pregnancy, nurse,
even if there's a famine
- "Cleavage" may form duplicate genital signal
replacing "sexual skin"
- Fake smooth, unblemished, hairless skin (better "rendered" skin = better genetics) via makeup
- Alternate "scrawny model" body
- Implies "hyper-virginity" (girl body on
adult woman)
- Non-aggressive behavior
- Good with children
- Supportive to other adults (not too
self-centerd)
- Keep group together at all costs (focus
on preventing socials breaks/violence)
EVOLUTION OF HUMAN SOCIAL BEHAVIOR
Dominance and
social organization
Dominance/submission forms the basis of
order in social animals
- Levels in dominance (see "bad girl" and "bad boy" Hollywood movies
for examples)
- Alpha - leader of particular gender, possibly entire group
- Beta - fawning, try to model themselves after alpha, associate,
curry favor
- Gamma-omega - just live their lives
- Scapegoat - lowest-ranking, everyone else picks on them
- Dominance ensures access to best food, mates and other resources
- Dominant individuals get first crack at food
- Dominant males may attract a "harem" of females maximizing the number of children they produce.
"...According to conqueror Genghis Kahn (mid 12th century), the sweetest
pleasure in life was 'to chase and defeat his enemy, seize his total
possessions, leave his married women weeping and wailing, ride his horse and
use the bodies of his women as a blanket and bedframe...Kahn was so
successful at this that a recent study of 2,213 men across Asia allowed
scientists to estimate that he may have as many as 16 million male
descendants spread out from Manchuria to Afghanistan..."
- Dominant females can get the best
males, and have lots of children, can "offload" children to lower-ranking
females (wet nurses, nannys) and ensure the survival of all their
children and grandchildren.
- Dominant females may also prevent other females from breeding, force them to
raise their children as their own (examples: wolves, Saddle-Backed
tamarin monkey females)
- Dominant males may kill the children of other males, causing
females to come into heat (not seen in humans, but step-parents of both
sexes are less loving to non-biological children)
- Dominating and being dominated are
common sexual fantasies in both
males and females
- Dominant animals (including humans) differentiate themselves by
- "Healthiness" (bodily wealth
due to increased access to resources)
- Aggression
(conflict and resolution creates dominance hierarchy)
- Boldness (risk-taking)
- "Cleverness" (chimp with drum example)
- Material wealth (particularly humans)
- Dominant animals "keep the peace", reduce violence and hold the
social order together
- Major role of "harem" males - break up fights between females (gorilla)
- Dominant animals act like "traffic cops" - without them, the animal society
order
degenerates
http://www.newscientist.com/article.ns?id=dn8635
"...While (the dominant males) were gone, group cohesion rapidly began to
disintegrate. The researchers saw cliques forming and the breakdown of
social networks and contact through communal activities like playing,
grooming and sitting together. The amount of violence also escalated,
with no one to broker the peace..."
- Dominant doesn't always mean smart (it's
just one factor of many)
- Older individuals often sexually dominate younger ones
