Lecture 7 Flashcards
(14 cards)
What is fitness?
the expected reproductive success of an individual with a particular phenotype or genotype
what are the components of fitness?
- survival to reproductive age
- mating success
- fecundity (number of offspring you have average during life)
What is relative fitness?
the fitness of a genotype standardized by comparison to other genotypes
How do we calculate relative fitness?
dividing it by the fitness of the most fit genotype in the population
What is the fitness equation?
fitness=(probability of survial)(average number of offspring)
When does natural selection occur?
when genotypes differ in average fitness
What are the two pieces of information needed for prediction?
- initial allele frequency
- fitness of the genotypes at the locus of interest
How do you calculate relative fitness?
divide by the absolute fitness of the most fit genotype (how fit is each genotype relative to the most fit)
How do you get absolute fitness?
multiply survival by fecundity
If directional selection is maintained, what does that mean for allele frequnecy?
a favorable allele will increase in frequency
When is change in a population the fastest
when the selection is strong (larger difference in relative fitness) and allele frequencies are similar
What does it mean when an allele is additive?
allele yields twice the phenotypic effect when two copies present
What is dominance?
dominant allele masks presence of recessive in heterozygote
Does the dominant allele ever go to fixation?
No
