Monday, 7 May 2007

Biology [[Classification, Selection and Evolution]] Artificial Selection

Selection pressures can be applied by humans, and these are sometimes the most important. Artificial selection is defined as humans purposely applying selection pressures to populations.

For Example: Cattle

Desired features indclude
*Docility
*fast growth rates
*high milk yield

Increses in these characteristics have been achieved by selective breeding.

*Inidviduals showing one or more of these traits to a larger degree than others are selected for breeding. Some of the alleles for theses features are passed on to their offspring.
*The best from the second generations are picked and breed

Over many generations, the allele frequency for the chosen characteristics will increase. In many cases, disadvantageous alleles are lost completely.

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