Transcript Natural Selection & Predator

Natural Selection &
Predator-Prey Interaction
April 10, 2003
Steven J. Ehrlich
Today
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Notes and Terms
Game
What to turn in:
* Tables from pages 147-152
Terms
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Predation – When
individuals eat other
living individuals.
Adaptation – When
newly-evolved traits
increase the ability of an
organism to survive.
Terms (continued)
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Fitness (In Natural Selection) –
A Genotype’s (or phenotype’s)
reproductive contribution to
subsequent generations
relative to the contribution of
other genotypes or phenotypes
Terms (continued)
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Coevolution – The process of
reciprocal evolutionary
changes, involving the
response of two or more
populations.
Morphs – A phenotype of a
species.
Natural Selection
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Darwin’s Theory
– Genotypes / Phenotypes
– “Only the strong survive”
– Predation, Adaptation, Co-evolution &
Fitness
Natural Selection Game
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Description of the game – Using 3 different utensils
(predators), we will pick up 4 different types of
beans (prey), to see which is the most fit predator,
and the most fit prey.
Natural Selection Game (continued)
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The rules –
– Groups
– Predators/prey
– 2x2 meter
– 2 minutes
– Calculations
– Generations
Natural Selection Game (continued)
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Formulas used
– Handout
– Fitness Formula (Predator):
Wi = Ci/ΣC
Ni/ΣN
Or
Fitness of knife = # of captures by the knife/ total # of captures
# of knives / total number of predators
Natural Selection Game (continued)
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Fitness Formula (prey):
wj = ej / Σe
nj / Σn
Fitness of Pinto = # of pinto escapes / total # of escapes
# of pinto beans / total # of beans