Allele: one of two or more versions of a gene. An individual inherits two alleles for each gene, one from each parent.

Allele frequencies: the frequency of occurrence or proportions of different alleles for a particular gene in a given population.

Gene flow: the transfer of alleles or genes from one population to another.

Phenology: periodic plant and animal life-cycle events that are influenced by climate and seasonal change in the environment. Eg. flowering in the spring due to changes in daylight length. Oysters begin spawning when the water temperature reaches a certain temperature.

Phylogeography: the study of the genetic and geographic structure of populations and species; generally uses genetic information to examine genealogical history and patterning within species and populations.

Population genetics: the study of changes in allele frequencies in population of organisms and the effects of such changes on evolution and adaptation. Natural selection, genetic drift, mutations, and gene flow can cause these changes.