Free Artificial Selection OCR A Level Biology revision notes – covering specification points 6.1.2(hi) and 6.1.2(hii).
Artificial selection is carried out in order to enhance the desirable characteristics of organisms.
The Process of Artificial Selection
The process of artificial selection can be simplified into the following stages:
- Individuals within the population who have the best version of the desired characteristic are identified and selected.
- Selected individuals are crossed (bred) with each other to produce offspring.
- Offspring with the best version of the desired characteristic are identified and selected.
- Selected individuals are crossed (bred) with each other to produce offspring.
- The process is repeated over many generations.
The process of artificial selection utilises a small breeding population, which leads to a significant reduction in genetic diversity.
Conserving Genetic Variation
Artificial selection reduces genetic variation over successive generations, so breeders must take active steps to conserve and maintain the genetic diversity of the population in order to maintain its adaptive capacity and overall health.
Genetic variation within a breeding population can be maintained through management or preservation:
- Management of selective breeding programs minimises the chances of inbreeding and genetic drift.
- Preserving genetic material allows for alleles to be stored within gene banks and other repositories so that they can be introduced into the population as and when needed.
Ethical Considerations of Artificial Selection
The effects of artificial selection on organisms that undergo artificial selection raise ethical concerns relating to their genetic diversity and survival:
- Genetic diversity: Breeding from a limited number of individuals reduces their genetic variation, increasing susceptibility to disease and reducing adaptability.
- Survival: Selectively bred organisms may have a reduced ability to defend themselves and a reduced tolerance to environmental conditions.