Artificial Selection

Artificial Selection

• In natural selection, the natural environment chooses which organisms are allowed to reproduce and pass their genes on to the next generation. But for thousands of years, human beings have been doing something rather similar on purpose. They have been choosing which of their crop plants and livestock are allowed to pass on their genes and changing their crops and livestock as a result. This process is called artificial selection or selective breeding.
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• Pie de imagen: Dog breeds are an example of selective breeding.

Crop Plants and Livestock

• The key step in selective breeding is to survey all of your growing crop plants and select those which show best the feature you want to develop. For example, if you want to increase the yield of wheat plants, you select the few wheat plants that are producing the most grain. You then collect the seeds from these plants and use only them to grow next year's crop. if you repeat this over several years, the crop will gradually become better-yielding.
• Similar techniques have also been used over centuries to breed cows producing more milk or better meat, hens laying more eggs, sheep producing better-quality wool, dogs with particular character traits, and so on.
• With animals, of course, you need to select both a male and a female to produce the new offspring. Since the 1950s, this has been made easier by a technique called artificial insemination. The semen from a single bull with desirable characteristics is collected and frozen for storage. It is then transported to many different formats and used to fertilize the eggs of thousands of cows.
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• Pie de imagen: Selective breeding of corn over time