Download Genetic Equilibrium Honors Biology Mr. Lee Room 320

Genetic Equilibrium
Honors Biology
Facilitator: Mr. Lee
Room 320
Objectives


Describe causes of genotypic variation in a
population
Explain Hardy-Weinberg genetic equilibrium
Variation of Traits
in a Population

The study of evolution from a genetic point of
view is called Population Genetics
 A population is a group of individuals of the
same species that interbreed
 Within a population, individuals can have
different phenotypes
Variation of Traits
in a Population


Biologist use graphs such as a bell curve to
show frequency of a given trait in a population
Individuals represented by the two ends are
those with extreme variation of a specific trait
Causes of Variation

The three main sources of genetic variation
are:
 Mutations: results from flawed copies of
individual genes
 Recombination: reassociation of genes in a
diploid individual
 Random fusion of gametes
Allele Frequencies
& the Gene Pool

Genetic variations is studied in populations
(group of individuals of the same species that
interbreed)
 Gene pool- consists of all the genes, and
alleles, that are present in a population
 Relative frequency of an alleles is the
number of times that an allele occurs in a
gene pool
Allele Frequencies
& the Gene Pool…


Allele frequency is determined by dividing
the number of a certain allele by the total
number of alleles of all the types in a
population
Phenotype frequency is the number of
individuals with a particular phenotype within
a population
Hardy-Weinberg principle


This is a tool used by scientist to determine
what forces are disrupting genetic equilibrium
Five conditions are required to maintain genetic
equilibrium from generation to generation:
 No Mutation
 Individuals neither enter nor leave the
population
 The population in large
 Individuals mate randomly
 Selection does not occur
Review


Describe causes of genotypic variation in a
population:
 Mutations
 Recombination
 Random fusion of gametes
Explain Hardy-Weinberg genetic equilibrium:
 This is a tool used by scientist to determine
what forces are disrupting genetic equilibrium
 Sets up a hypothetical population that is not
evolving