Population genetics

For the following part it is usefull to have a basic understanding of genetics.

With population genetics you do no longer look at individuals and what offspring they will produce, but you look at the population as a whole. A population is a group of birds that are one way or the other separated from the rest of the specie. Population genetics is the study of the partitioning and evolution of hereditary traits in a population. So we are no longer interested in the hereditary traits of one bird. There are many articles about heredity. Most of these handle the genetics of the different colours. Posture is the most important factor for our budgerigar. Traits like size, feather length, ... inherit at first sight do not behave according to the rules by Mendel. This section tries, starting from population genetics, to explain how the Mendelian heredity is important for selection.

Hardy & Weinberg equilibrium for populations is a nice starting point about population genetics.