NationMaster - Encyclopedia: Artificial selection

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 â€“ 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 GalÃ¡pagos 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".

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

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Basic topics in evolutionary biology

Evidence of evolution The GalÃ¡pagos Islands hold 13 species of finches that are closely related and differ most markedly in the shape of their beaks. ... It has been suggested that Dysgenics be merged into this article or section. ... Inbreeding is breeding between close relatives, whether plant or animal. ... Evolutionary biology is a subfield of biology concerned with the origin and descent of species, as well as their change, multiplication, and diversity over time. ... While on board HMS Beagle, Charles Darwin collected numerous specimens, many new to science, which supported his later theory of evolution by natural selection. ...

Processes of evolution: adaptation - macroevolution - microevolution - speciation This article is about evolution in biology. ... hi A biological adaptation is an anatomical structure, physiological process or behavioral trait of an organism that has evolved over a period of time by the process of natural selection such that it increases the expected long-term reproductive success of the organism. ... Macroevolution refers to evolution that occurs above the level of species, in contrast with microevolution, which refers to smaller evolutionary changes (typically described as changes in allele frequencies) within a species or population. ... Microevolution is the occurrence of small-scale changes in allele frequencies in a population, over a few generations, also known as change at or below the species level. ... Charles Darwins first sketch of an evolutionary tree from his First Notebook on Transmutation of Species (1837) Speciation is the evolutionary process by which new biological species arise. ...

Population genetic mechanisms: selection - genetic drift - gene flow - mutation Population genetics is the study of the distribution of and change in allele frequencies under the influence of the four evolutionary forces: natural selection, genetic drift, mutation, and migration. ... Selection is hierachically classified into natural and artificial selection. ... Genetic drift is the term used in population genetics to refer to the statistical drift over time of allele frequencies in a finite population due to random sampling effects in the formation of successive generations. ... Gene flow (also known as gene migration) is the transfer of genes from one population to another. ... In biology, mutations are changes to the genetic material (either DNA or RNA). ...

Evo-devo concepts: phenotypic plasticity - canalisation - modularity Evolutionary developmental biology (evolution of development or informally, evo-devo) is a field of biology that compares the developmental processes of different animals in an attempt to determine the ancestral relationship between organisms and how developmental processes evolved. ... We dont have an article called Phenotypic plasticity Start this article Search for Phenotypic plasticity in. ... Norms of reaction for two genotypes. ... Many organisms consist of modules, both anatomically and in their metabolism. ...

Modes of evolution: anagenesis - catagenesis - cladogenesis Anagenesis is the progressive evolution of species involving a change in gene frequency in an entire population rather than a cladogenetic branching event. ... Catagenesis is an archaic term from evolutionary biology referring to evolutionary directions that were considered retrogressive. ... Cladogenesis is an evolutionary splitting event in which each branch and its smaller branches is a clade; an evolutionary mechanism and a process of adaptive evolution that leads to the development of a greater variety of animals or plants. ...

History: History of evolutionary thought - Charles Darwin - The Origin of Species - modern evolutionary synthesis The history of evolutionary thought is very long, since the idea of biological evolution has existed since ancient times, but the modern theory wasnt established until the 18th and 19th centuries, with scientists such as Jean-Baptiste Lamarck and Charles Darwin. ... Charles Robert Darwin (12 February 1809 â€“ 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. ... British naturalist Charles Darwins book, The Origin of Species, is one of the pivotal works in scientific literature and arguably the pre-eminent work in biology. ... The modern evolutionary synthesis (often referred to simply as the new synthesis, the modern synthesis, the evolutionary synthesis, neo-Darwinian synthesis or neo-Darwinism), generally denotes the integration of Charles Darwins theory of the evolution of species by natural selection, Gregor Mendels theory of genetics as the basis...

Other subfields: ecological genetics - human evolution - molecular evolution - phylogenetics - systematics Ecological genetics is the study of genetics (itself a field of biology) from an ecological perspective. ... This article does not cite its references or sources. ... Molecular evolution is the process of the genetic material in populations of organisms changing over time. ... In biology, phylogenetics (Greek: phylon = tribe, race and genetikos = relative to birth, from genesis = birth) is the study of evolutionary relatedness among various groups of organisms (e. ... In biology, systematics is the study of the diversity of organism characteristics, and especially how they relate evolutionarily. ...

List of evolutionary biology topics - Timeline of evolution This is a list of topics in evolutionary biology and evolution. ... This timeline of the evolution of life outlines the major events in the development of life on the planet Earth. ...

Contrast to natural selection GA_googleFillSlot("encyclopedia_square");

Examples of artificial selection

See also

Contrast to natural selection