Transcript Evolution: Basic Principles

Evolution: Basic Principles
Evolution: Change over time; decent with
modification
Natural Selection: Primary mechanism
producing evolution (change over time).
There are other mechanisms such as:
sexual selection, social selection, drift.
Basic principles of NS:
1.
Variability: stuff varies
2.
Heritability: variation is passed on
genetically
3.
Competition: limited resources
4.
Selection: some variations are
advantageous in securing limited
resources and tend to passed on more
than others = change over time
Sexual selection
Some traits may actually be detrimental to
survival but provide an advantage in mating.
Sexual selection: intra-sexual competition
• Typically male-male
competition for mates,
resources, and status.
Intra-sexual coalitional competition
• Chimpanzees are especially
well-known for forming male
coalitions to challenge other
males for dominance.
Evolutionary basis for male competition
• Gamete size (cheap sperm vs. expensive
eggs)
• Parental investment (mating vs.
parenting effort)
• Parental certainty (paternal vs. maternal
certainty)
Social Selection
• Some traits help animals get along better in their social
groups which in turn increases their survival and
reproduction. Ex: more socially skilled female baboons
tend to have more surviving offspring.
Female competition
• Usually less one on
one physical than
male competition.
Typically relational,
social exclusionary,
sexually targeted.
Human mate attraction: Long term mates
• Males: young, beautiful,
sexually modest
• Reproductive value;
paternity certainty
• Females: older, highstatus (or potential),
robust
• Good genetics, stable
secure source of
resources,
Brain and social selection
• Larger groups select for
more neocortex.
Ten Politically Incorrect Truths About
Human Nature
1. Men like blond bombshells (and
women want to look like them)
•
Why? Beauty is a indicator of fertility. Blonde is
an indicator of honest signally (modesty)
•
See my webpage for full discussion
•
Excerpted from Why Beautiful People Have More Daughters, by Alan S. Miller and Satoshi Kanazawa, to be
published by Perigree in September 2007.
2. Humans are naturally
polygamous
• Males want harem of young
fertile females
• Females want good genes and
lots of resources
• However both want some
reproductive success more than
none so both usually have to
compromise (monogomy)
• 3. Most women benefit from
polygyny, while most men
benefit from monogamy
• Females: Better to have 10% of
Bill Gates than 100% of Homer
Simpson
• Males: share the babes!
• 4. Most suicide bombers are
Muslim
• Polygyny increases ‘loser’ males
• Islam promises loser males
reproductive success in afterlife
• 5. Having sons reduces the
likelihood of divorce
• Resources/status inheritance
more critical for son’s
reproductive success
(reproductive variance)
• 6. Beautiful people have more
daughters
•
Beauty is a more valuable trait for female
reproductive success than for male,
especially among lower economic status
couples (Trivers-Willard Hypo). Goodlooking, non-rich couples tend to have more
females. (I have four daughters, beauty +
lower status)
7. What Bill Gates and Paul
McCartney have in common with
criminals
Young male risk-taking behavior
• 8. The midlife crisis is a myth—
sort of
• Male midlife crisis is real but
cause by their wife’s age not
their own.
• 9. It's natural for politicians to
risk everything for an affair (but
only if they're male)
•
Power is a means to achieve reproductive
success for males. It actually makes no
sense (genetically) to not have affairs once
you have achieved power!
• 10. Men sexually harass women
because they are not sexist
• Wrong motivation – it’s not men
treating women differently its
men treating women as they do
other men. That is using their
power to achieve advantage for
purposes of reproductive
success.