- Special case of natural selection where one sex (usually the female) acts as the selecting agent
Artificial selection
- People select individuals to breed with desirable features. eg cows with no milk
- Humans develop breeds within species by starting with small original gene pools, not allowing immigration and selecting favourable characteristics.
- This is much faster than natural selection due to inbreeding, breeding closely related individuals. But the disadvantage is that it increases the chances of harmful recessive alleles being expressed in the phenotype.
Mutations
- Mutations are sources of new alleles, so are needed for evolution. If a mutation occurs in gametes and the gamete is fertilised, the mutation will enter the gene pool. Alleles from favourable mutations increase in frequency in the gene pool because they are selected for.