We explain what artificial selection or selective breeding is, its types, advantages, disadvantages and examples. Also, natural selection.
What is artificial selection?
Artificial selection, or selective breeding, is called ways in which human beings intervene by changing the heritable characteristics of various species according to productive, aesthetic or convenience criteria.
For both animals and plants, artificial selection consists of achieving mechanisms that allow many specimens with particular characteristics to be obtained.
Humanity has used this resource since the first animal and plant species were subjected to domestication. For this reason, domestic animals and plants of agronomic interest have followed a different evolutionary path than their wild relatives.
The most traditional technique of artificial selection consists of choose parents with desirable qualities and then select their descendants, to repeat the process in the next generation.
Currently, there are other forms of artificial selection that involve genetic engineering techniques and the obtaining of genetically modified organisms (GMOs).
Unlike natural selection, which postulates that the prevalence of advantageous characteristics of a species is determined by its natural environment, artificial selection involves direct human intervention to determine which traits should be favored in a species and which should not.
Artificial selection is an example of how closeness to humans and their way of life has significantly conditioned the biological evolution of certain species.
- See also: Genetic manipulation
How is artificial selection done?
Artificial selection is based on establish control over the reproduction of species.
The idea is to choose parents with certain characteristics and make them have offspring. Then those descendants that have the desired characteristics are selected and the process is repeated in the next generation.
The objective is to obtain a greater number of specimens that have a certain trait of interest (aesthetic, resistance, productivity, etc.).
Today, advances in the field of genetic engineering have given the possibility of modifying the characteristics of a species, through the creation of transgenic organisms.
- It may help you: Transgenic foods
Advantages of artificial selection
Artificial selection made it possible to satisfy human needs more easily, because it contributed to the process of domestication of animals and the cultivation of edible vegetables.
Agriculture and livestock are based on artificial selection ly constitute important engines of progress for humanity.
Likewise, domesticated species can also obtain certain advantages by living closely with humans.
For example, for animals, survival may be more comfortable in an established home (with constant food and absence of predators) than in their original wild environment.
Disadvantages of artificial selection
One of the disadvantages that brings with it artificial selection is the weakening of the species: Animals and plants can be susceptible to diseases and problems that arise from belonging to closed populations.
One of the reasons why this occurs has to do with the lack of genetic variability in crops or animal farms. When crossings occur between very close relatives, an increase in genetic diseases may appear uncommon.
It happens that, while trying to obtain descendants that have certain characteristics of interest, it may also happen that the prevalence of other traits that compromise survival is favored. For example, you can get dogs with a very beautiful coat that, at the same time, are highly predisposed to having recurrent infections.
Examples of artificial selection in animals
Some examples of artificial selection in animals are:
- Breeding the different breeds of domestic dog both those for company (generally small) and those on guard or fighting (generally large).
- The extinction of some violent or dangerous breeds of dog or cat through the control or reduction of its reproduction.
- Production of salmon and other fish grown in fish farms.
Examples of artificial selection in plants
One of the best-known examples of artificial selection is that of the corn plant which underwent important changes from its original form, the teosinte.
Teosinte is a small plant with hard and few grains, native to the central region of Mexico. Since the beginning of agriculture, Humans began to select plants with softer grains to use them as food.
Farmers saved the seeds from the largest, softest ears and then planted them the following year. This meant that, over time, the selective cultivation of the wild teosinte plant gave rise to the current corn plant. Some research suggests that there was also an effect of natural selection in this process.
It is believed that the origin of corn is Mexican because Mexico is the only place where archaeological evidence was found that teosinte and corn plants coexisted thousands of years ago.
Later, corn cultivation spread to other regions of the world. It first spread throughout Latin America. Then, it reached the United States and Canada. Finally Christopher Columbus brought corn to Spain, where its cultivation spread very quickly to different European countries. Later, corn reached Asia and Africa through trade.
Currently the teosinte is considered an endangered species. However, in Mexico wild teosinte is found in almost all regions of the country.
Other examples of artificial selection in plants are wheat, apples, rice and potatoes.
What is natural selection?
Unlike artificial selection, natural selection is the adaptation process of species in their wild habitat according to the demands of your environment.
Natural selection is a concept coined by the British naturalist Charles Darwin. It postulates that biological evolution occurs from advantageous hereditary characteristics that prevail over others, according to environmental conditions.
According to Darwin's theory, natural selection is the main engine of evolution and the creation of species.
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References
- Bombara N., Godoy E., et al. BIOLOGY 2: Origin, evolution and continuity of biological systems. 1st edition. Santillana (2018)
- Ginnobili, S. (2011). Artificial selection, sexual selection, natural selection. Metatheoria, 2(1), 61-78. Available in RIDAA-UNQ Open Access Digital Institutional Repository of the National University of Quilmes http://ridaa.unq.edu.ar/