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Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant males and females will sexually reproduce and have offspring together.
The Himalayan rabbit and the Siamese cat are examples of artificial selection on heterotopy, developed by breeders incidentally long before the concept was understood. The current theory is that people selected for stereotypical phenotypic patterns (dark extremities) that happened to be repeatedly produced given a typical temperature.
The existence of limits in artificial selection experiments was discussed in the scientific literature in the 1940s or earlier. [1] The most obvious possible cause of reaching a limit (or plateau) when a population is under continued directional selection is that all of the additive-genetic variation (see additive genetic effects) related to that trait gets "used up" or fixed. [2]
The red junglefowl (Gallus gallus), often believed to be an ancestor of the domestic chicken.. Most animals are tuned to modern life by artificial selection. This is either due to the pressure of early hunter-gatherers' attempts to stabilise the food supply, which resulted in the existence of domesticated farm animals, or domestication of pets which are useful to humans. [2]
For example, food preferences are assumed to be largely the same in domesticated animals as in their wild type ancestors. Natural selection might serve as an additional tool in creating "authentic" robustness, "authentic" behaviour, and perhaps, the original phenotype as well. In some cases, a sufficient predator population would be necessary ...
One example of this change in breeding goals is the pronounced sloped back in the modern German Shepherd breed, compared to the straight back of working pedigrees. The Shar Pei is an example of how differing breed standards can influence the direction breeders take a dog and which traits are exaggerated.
A major technological application of evolution is artificial selection, which is the intentional selection of certain traits in a population of organisms.Humans have used artificial selection for thousands of years in the domestication of plants and animals. [4]
The process of artificial selection has had a significant impact on the evolution of domestic animals. For example, people have produced different types of dogs by controlled breeding. The differences in size between the Chihuahua and the Great Dane are the result of artificial selection.