BIOL 3445 Lecture Notes - Lecture 27: Evolutionarily Stable Strategy, Eusociality, Group Selection
BIOL 3445.001 | Lecture #27 | 4/24/2018
Behavior and Game Theory
OBJECTIVES
― Explain how a behavior can evolve through natural selection
― Why have scientists decided that “group selection” is not a real thing?
― What is an evolutionary stable strategy?
― Why is behavior often under frequency-dependent selection?
― What does inclusive fitness include?
― Under what conditions might eusociality evolve?
WHAT IS BEHAVIOR?
― Behavior: an internally-generated response to an external stimulus
o Evolves via natural selection
o Can be thought of as a part of the phenotype
How Does Behavior Evolve?
― Behavior can evolve like any other trait
― EXAMPLE: Russian Fox Taming Experiment
o Russian silver foxes are bred for the coats
▪ The foxes usually don’t do well in captivity and would often fight
with each other and bite their handlers
o Foxes were scored for tameness
o Offspring strongly resembled their parents
▪ Tame foxes tend to have tame offspring
▪ Aggressive foxes tended to have aggressive offspring
o Found that tameness is a heritable trait
o Selective breeding of only the tamest foxes results in a change in behavior
o Scientists can find the specific genes that differ between the tame and
aggressive foxes
▪ Gene expression differs in the brains of tame and aggressive foxes
o The experiment was both successful and a failure
▪ The foxes were tame and didn’t bit the handlers when they came
in the room – successs!
▪ The foxes developed puppy-like traits from corresponding genes
(floppy ears, dog-like colorings, curled tail, etc.) and people didn’t
want to wear dog-like fur coats - failure
― EXAMPLE: Mouse Wheel-Running Experiment
o Selectively breed mice that run more often on their wheels
o After many generations, scientists developed a population of mice that
run a lot
o You can put a wheel in the woods and mice will come run on it
▪ They love to run – very active, muscly creatures
o You can push a behavior beyond “normal” levels just like any other trait
find more resources at oneclass.com
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Document Summary
Explain how a behavior can evolve through natural selection. Behavior: an internally-generated response to an external stimulus: evolves via natural selection, can be thought of as a part of the phenotype. Behavior can evolve like any other trait. Example: russian fox taming experiment: russian silver foxes are bred for the coats. The foxes usually don"t do well in captivity and would often fight with each other and bite their handlers: foxes were scored for tameness, offspring strongly resembled their parents. The foxes were tame and didn"t bit the handlers when they came in the room successs! The foxes developed puppy-like traits from corresponding genes (floppy ears, dog-like colorings, curled tail, etc. ) and people didn"t want to wear dog-like fur coats - failure. They love to run very active, muscly creatures: you can push a behavior beyond normal levels just like any other trait.
