What does capital S denote?
the selection differential is the mean difference between mating individuals and all individuals
What is the formula for selection differential?
S = mean Xs(reproducing individuals) - Mean Xp(population)
What does S infer?
The strength of selection
What is the response to selection?
R is the change in the mean phenotype value between generations
What is the big equation needed to determine R, S, and H^2?
The Breeder’s equation: R = (h^2)*S
What is the formula for R?
Mean P_t+1 = Mean P_t + R
How many generations does the breeder’s equation encompass?
Only 1 generation
What are 2 assumptions of the breeder’s equation?
- The strength of selection has been measured perfectly
- Traits are independent of other traits
What are the 3 modes of selection on quantitative traits?
- Directional
- Stabilizing
- Disruptive
What is stabilizing selection?
It is selection favouring intermediate phenotype values
What will happen to the mean and variance of a population with stabilizing selection?
The mean will stay the same and variance will decrease
What is disruptive selection?
A rare type of selection where individuals with extreme phenotypes are more successful
What is a long term consequence of disruptive selection?
Speciation
What is the difference between modes of selection graphs of discrete vs continuous/quantitative traits?
It deals with the phenotypic distribution, not the fate of alleles
What are two reasons why phenotypic states are not indicative of the genotypic level of activity?
- Heterozygotes can have extreme phenotypes
- Intermediate phenotypes may be fixed for mixes of high and low alleles at different loci
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Introduction / Genetics and Mutation44
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Inheritance and HWE24
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Natural Selection36
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Natural Selection 221
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Natural Selection 315
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Adaptation 19
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Adaptation 214
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Genetic Drift29
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Gene Flow26
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Origin of Species21
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Speciation 226
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Phylogeny32
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Phylogeny 234
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Human Evolution40
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Evolution of Sex59
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Evolution of Sociality40
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Interaction Species 145
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Interacting Species 237
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Interacting Species 323
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Macroevolution36
