Population Genetics

Alleles  -  Variations of a given gene.

allelic frequencies  -  The frequency with which a particular allele appears among the possible alleles in a population.

Fitness  -  The probability that an individual will contribute its genes to the next generation.

Genetic drift  -  Random changes in allelic frequencies due to chance rather than selection.

Hardy-Weinberg equation  -  An equation used to find the allele frequencies in a population at Hardy-Weinberg equilibrium. For a two allele system, the Hardy-Weinberg equation would be (p + q)² = 1 or p ² +2pq + q ² = 1 .

Hardy-Weinberg equilibrium  -  A state in which phenotypic and allelic frequencies remain constant from generation to generation in sexually reproducing populations.

Natural Selection  -  The theory holding that competition exists within species, determining which species live to have offspring and pass their traits on to those offspring.

Phenotype  -  The traits or characteristics an individual displays.