20.5 Evolution Flashcards
Definition of population
A group of organism of the same species occupying a particular space at a particular time that can potentially interbreed
What’s is population genetics?
The study of variations with populations, and the forces which shape it
Definition of gene pool
The total number of alleles in a population at a given time
Definition of allele frequency
The relative frequency of a particular allele in a population
How do different alleles arise in a population?
Random mutation, migrations
Definition of evolution
The change in allele frequencies in a population overtime
What are the reasons for a change in allele frequencies?
Mutations, migration, selection, genetic drift
What is genetic drift?
The change in the relative frequency of different genotypes due to chance; disappearance of a particular allele as individuals die or do not reproduces. It is random
In what type of population does genetic drift affect a population the most?
Smaller populations
How is allele frequency calculated?
p + q = 1
where p is frequency of dominant allele
and
q is frequency of recessive allele
What is the answer to the allele frequency equation?
Always 1
What does the Hardy-Weinberg principle state?
In a stable population with no distributing factors, the allele frequencies will remain constant from one generation to the next and there will be no evolution
What is the equation for the Hardy-Weinberg principle?
p² + 2pq + q² = 1
p² = frequency of homozygous dominant genotype in the population
2pq = frequency of heterozygous genotype in the population
q² = frequency of homozygous recessive genotype in the population
What does p² represent in the Hardy-Weinberg principle?
Frequency of homozygous domains genotype in the population
What does 2pq represent in the Hardy-Weinberg principle?
Frequency of heterozygous genotype in the population
What does q² represent in the Hardy-Weinberg principle?
Frequency of homozygous recessive genotype in the population
The Hardy-Weinberg principle will be true provided by what?
-No mutations arise
-The population is isolated (no immigration, emigration)
-There is no artificial or natural selection
-The population is large
-Mating with the population is random
What happens if the Hardy-Weinberg principle is not maintained at equilibrium?
Evolution
What can the Hardy-Weinberg equation be used for?
To estimate the frequency of alleles, genotype and phenotypes in a population and see if they change over time
