Transcript Evolution: Basic Principles

Chapter 1: Goetz, A. T., & Shackelford, T. K. Introduction to evolutionary
theory and its modern application to human behavior and cognition (pp. 1-20).
• Evolutionary ideas predate Darwin:
Anaximander Greek philosopher (c. 610
BC – c. 546 BC)
• Authors give us an unreferenced quote:
“in water the first animal arose covered
with spiny skin and with the lapse of
time some crawled onto dry land…”
• Darwin’s contribution was the major
mechanism by which evolution could
operate: Natural selection
• Distinguish Natural Selection from
Sexual Selection.
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
Spencer’s misleading summary of NS: “survival
of the fittest.”
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.
Other key concepts
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Modern Synthesis: combo of Darwinian selection with Mendelian genetics.
Adaptations: inherited, phenotypic solutions to adaptive problems
Byproducts: non-adaptive incidental tag-alongs to adaptive traits. Navel is
byproduct of adaptation of umbilical connection of mammalian mother to
offspring.
Noise: Random non-adaptive characteristics of adaptations or byproducts.
Inny vs. outie navel; dry hair, frizzy hair etc.
Evolutionary psychology: human mental/emotional functioning as
evolved solutions to adaptive problems.
Ex: face processing; jealousy. Inputs-decision rules- outputs
More concepts
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Domain specificity: A psychological adaptation is
specific to an adaptive problem, does not apply
generally to a range of potential problems. Ex: cheater
detection mechanism. Controversy as to how
widespread this type of design is.
EEA: Environment of Evolutionary Adaptiveness. The
original selection pressures which shaped the present
adaptation.
Inclusive fitness: W.D. Hamilton – fitness should
include not just direct offspring but kin offspring as well;
gene’s eye view of evolution
Connection to sociobiology: EP – greater emphasis
on psychological mechanisms and less on current
adaptive significance. Humans as “adaption executers,
not fitness maximizers.”
Key concept: NS cannot make you have alot of
offspring, it can only motivate you to engage in those
behaviors that in the past were associated with higher
rates of reproduction.
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.