Selective breeding is the traditional method for improving crops and livestock, such as increasing disease resistance or milk yield.
Natural selection and selective breeding can both cause changes in animals and plants. The difference between the two is that natural selection happens naturally, but selective breeding only occurs when humans intervene. For this reason selective breeding is sometimes called artificial selection.
Different varieties of plants and animals with desired characteristics can be developed by selective breeding. For example:
The new varieties may be economically important. For example, they may provide more or better quality food to feed people.
Example of selective breeding
Selective breeding takes place over many generations. These are the main steps involved:
Future generations of selectively bred plants and animals will all share very similar genes. This could make some diseases more dangerous as all the organisms would be affected. Also, there is an increased risk of genetic disease caused by recessive alleles.
All the genes and their different alleles within a population is its gene pool. Inbreeding can lead to the loss of alleles from the gene pool, making it more difficult to produce new varieties in the future.