Genetic Equilibrium Hardy - Weinberg

No Natural Selection affects variation in a population as the better adapted (more fit) individuals survive and reproduce, passing on their genes to successive generations.

Random Mating In animals, non-random mating is more often the case as the choice of mates is often an important part of behaviour (e.g. courtship rituals). Many plants self-pollinate, which is a form of inbreeding or non-random mating.

Large Breeding Population So that chance alone does not disrupt genetic equilibrium. The change in the gene pool of a small population due to random chance is genetic drift.

The bottleneck effect is a form of genetic drift that results from the near extinction of a population.

The founder effect is a form of genetic drift that results from a small number of individuals colonizing a new area. In both cases, allele frequencies can change dramatically.

ELLIS-VAN CREVELD syndrome, also known as is a rare genetic disorder characterized by short-limb dwarfism, polydactyly (additional fingers or toes), malformation of the bones of the wrist, dystrophy of the fingernails, partial hare-lip, cardiac malformation and often prenatal eruption of the teeth.

No Migration Immigration and emigration of individuals from a population will affect allele frequencies and therefore gene flow.

No Mutation Mutations, although rare, do constantly occur. They provide the source of new alleles, or variation upon which natural selection can take place.

Readings Genetic drift – p.14 Bottleneck effect Founder effect