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Encyclopedia > Artificial selection
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This Chihuahua mix and Great Dane show the wide range of dog breed sizes created using artificial selection.
This Chihuahua mix and Great Dane show the wide range of dog breed sizes created using artificial selection.
Carrots selectively bred to produce different of white and black.
Carrots selectively bred to produce different of white and black.

Artificial selection is the breeding of certain traits over others. It was originally defined by Charles Darwin in contrast to the process of natural selection, in which the differential reproduction of organisms with certain traits is attributed to improved survival and reproductive ability in the natural habitat of the organism. Artificial selection that produces an undesirable outcome from a human perspective is sometimes called negative selection (but note that this term has a better-established meaning as a type of natural selection). NICK IS GAY Image File history File links IMG013biglittledogFX_wb. ... Image File history File links IMG013biglittledogFX_wb. ... This article is about the breed of dog. ... This small dog of unknown parentage may be part Chihuahua or Miniature Pinscher. ... The Great Dane is a breed of dog known for its large size and gentle personality. ... Image File history File linksMetadata Download high resolution version (1675x2700, 3461 KB) From: http://ars. ... Image File history File linksMetadata Download high resolution version (1675x2700, 3461 KB) From: http://ars. ... Binomial name Daucus carota L. Percentages are relative to US recommendations for adults. ... Charles Robert Darwin (12 February 1809 – 19 April 1882) was an eminent English naturalist who achieved lasting fame by convincing the scientific community that species develop over time from a common origin. ... The Galápagos Islands hold 13 species of finches that are closely related and differ most markedly in the shape of their beaks. ... Habitat (from the Latin for it inhabits) is the place where a particular species lives and grows. ... In biology, negative selection is artificial selection in which negative, rather than positive traits of a species are selected. ...


Contrast to natural selection

The difference between natural and artificial selection centers on the difference in environment among organisms subject to the two processes. Essentially, in artificial selection, the fitness which is the amount of offsping an individual contributes to a population relative to other individuals in that same population of an organism is defined in part by its display of the traits being selected for by humans. Since humans either intentionally or unintentionally exert control over which organisms in a population reproduce or how many offspring they produce, the distribution of traits in the organisms' population will change. Fitness (often denoted in population genetics models) is a central concept in evolutionary theory. ...


It should be emphasized that there is no real difference in the genetic processes underlying artificial and natural selection, and that the concept of artificial selection was first introduced as an illustration of the wider process of natural selection. The selection process is termed "artificial" when human preferences or influences have a significant effect on the evolution of a particular population or species.


Examples of artificial selection

Most examples of artificial selection fall into the category of selective breeding, in which particular individuals are selected for breeding because they possess desired characteristics or excluded from breeding because their traits are undesirable. Both processes have contributed to the domestication of animals and plants by humans. Selective breeding in domesticated animals is the process of developing a cultivated breed over time. ... Dogs and sheep were among the first animals to be domesticated. ...


The most obvious examples of artificial selection can be found in the range of specialised body shapes and even personality types in bred in domesticated dogs. The wide range of sizes and shapes, from Dachshund to Wolfhound, shows the power of artificial selection through selective breeding. Systematic selective breeding has led to extreme traits such as the large size and eating habits of the Great Dane versus the small size of the Chihuahua. It is possible for traits to be selected for under artificial selection - for example, aggressive behavior in small dogs - that would be selected against in the natural environment absent human influence. An even more illustrative example is the domestication of corn, which has been bred so that it no longer disperses its seeds, instead relying on human intervention to disseminate them. Because both organisms derive significant benefits from the other, this could be termed a symbiotic relationship. Dog breeding is the vocation of mating carefully selected specimens to produce specific qualities and characteristics. ... Trinomial name Canis lupus familiaris The dog is a type of canine, a mammal in the order Carnivora. ... The dachshund is a short-legged, elongated dog breed of the hound family. ... The Irish Wolfhound is a breed of dog (a sighthound), bred to hunt. ... Selective breeding in domesticated animals is the process of developing a cultivated breed over time. ... The Great Dane is a breed of dog known for its large size and gentle personality. ... This article is about the breed of dog. ... Look up corn in Wiktionary, the free dictionary. ... Common Clownfish (Amphiprion ocellaris) in their Magnificent Sea Anemone (Heteractis magnifica) home. ...


Certain characteristics may unintentionally be encouraged while intentionally selecting for a desired result. For example, the domestic chicken has been bred to reach a large size relatively quickly (compared to its feral ancestors). The resulting changes in the chicken's gut have come at the expense of a reduced brain size and relatively smaller leg bones; these latter changes were not intentional artificial selections, but through a parallel process sometimes called "unconscious selection".

This 1845 painting of a Shorthorn bull by J. Loader shows how animals can be bred for size.
This 1845 painting of a Shorthorn bull by J. Loader shows how animals can be bred for size.

It is also possible for humans to exert artificial selection pressures on our own species, either unintentionally through social pressures, or intentionally. Eugenics efforts, in which those with "undesirable" characteristics are prevented from reproducing and those with "desirable" characteristics are encouraged to reproduce, form the most extreme such example. From http://www. ... From http://www. ... It has been suggested that Dysgenics be merged into this article or section. ...


See also


  Results from FactBites:
 
Artificial selection - Wikipedia, the free encyclopedia (795 words)
Artificial selection that produces an undesirable outcome from a human perspective is sometimes called negative selection (but note that this term has a better-established meaning as a type of natural selection).
Essentially, in artificial selection, the fitness of an organism is defined in part by its display of the traits being selected for by humans.
Most examples of artificial selection fall into the category of selective breeding, in which particular individuals are selected for breeding because they possess desired characteristics or excluded from breeding because their traits are undesirable.
Natural selection - Wikipedia, the free encyclopedia (5919 words)
Selection at a different level than the individual, for example the gene, can result in an increase in fitness for that gene, while at the same time reducing the fitness of the individuals carrying that gene (see intragenomic conflict for more details).
A strong selective sweep results in a region of the genome where the positively selected haplotype (the allele and its neighbours) are essentially the only ones that exist in the population.
Selective mating can be the result of, for example, a change in the physical environment (physical isolation by an extrinsic barrier), or by sexual selection resulting in assortative mating.
  More results at FactBites »

 
 

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