Natural selection - SpeedyLook encyclopedia

In Biology, the natural selection is one of the mechanisms which guide the evolution Espèces. This mechanism is particularly important owing to the fact that he explains the adaptation species to their medium. The Théorie of the natural selection makes it possible to explain how the Environnement influences the evolution of the Population S by selecting the most adapted individuals and thus constitutes a fundamental aspect of the theory of the evolution.

The natural selection indicates the fact that the hereditary features which support survival and the reproduction, see their frequency increasing from one generation to another. That rises logically owing to the fact that the carriers of these features have more descendants, and that the latter carry also these features (since they are hereditary).

History

Whereas several evolutionary theories existed already under the name of Transformisme, Charles Darwin (1809-1882) proposes this mechanism that one indicates it under the term of Darwinism or selection darwinienne . The " term; selection naturelle" was imagined by Darwin by Analogie with the artificial selection practiced by the human ones since of the millenia: the farmers or stockbreeders choose with each generation the individuals showing best the characteristics to make them reproduce. The mechanism of selection darwinienne thus makes it possible to explain way naturalist adaptive complexity of the living beings, without having recourse to the Finalisme nor with a supernaturelle intervention, of divine origin , for example.

Principles of the natural selection

The theory of the natural selection such as it was initially described by Charles Darwin, rests on three principles:

the principle of variation
the principle of adaptation
the principle of heredity

Principle 1: The individuals differ from/to each other

In general, in a Population individuals of same a Species, there exist more or less important differences between these individuals. In biology, one calls '' character '', all that is visible and can vary from one individual to another. It is said that there exists several milked for the same character. For example, at the human being, the Color of the skin, the color of the eyes are characters for which there exist multiple variations or features. The variation of a character at a given individual constitutes his Phénotype. It is there, the first condition so that there is natural selection: within a population, certain characters must present variations, it is the principle of variation .

Principle 2: The individuals most adapted to the medium survive and reproduce more

Certain individuals carry variations which enable them to reproduce more than the others, in a Environnement precise. It is said that they lay out of a selective Avantage on their congeneric:

the first possibility is, for example, that while escaping better the Prédateur S, while being less sick, while reaching food more easily, these individuals reach the adulthood more easily, to be suited to the reproduction. Those which have a better capacity of survival will be able to thus reproduce more.

In the particular case of the sexuée reproduction, the individuals having survived can be carrying a nature particularly attracting for the partners of opposite Sexe. These will be able to more generate a greater descent in copulating.

In both cases, the increase in the capacity to survive and to reproduce results by an increase in the Taux of reproduction and thus in a more descent, for the individuals carrying these characteristics. One says whereas this character trait given offers a selective Avantage, compared to others. It is in this principle of adaptation only, that intervenes the medium of life.

Principle 3: The advantageous characteristics must be hereditary

The third condition so that there is natural selection is that the characteristics of the individuals must be hereditary, i.e. they can be transmitted to their descent. Indeed certain characters, like bronzing or the culture, do not depend on the Génotype, i.e. the whole of the Gène S of the individual. At the time of the reproduction, in fact thus the genes, transmitted to the descendants, will involve the passage of certain characters of a generation with the other. It is the principle of heredity .

These the first three principles thus involve that the hereditary variations which confer a selective advantage will be more transmitted to the following generation the less advantageous variations. Indeed the individuals who carry the advantageous variations reproduce more. With the wire of the generations, one will thus see the Fréquence désavantageux genes decreasing until if required disappearing, while the advantageous variations will be spread in the population, until if required being divided by all the members of the population or the species. For example, in the human population, the Bipédie is a character common to all the modern human beings.

The natural selection explains the adaptation of the species to their medium

When one observes species in their medium of life, they all seem to be deeply adapted to each one of their medium: length Neck and the long legs of the Girafe are indeed well adapted to catch high sheets of the Acacia S of the African Savane S. One could just as easily say that in fact the not adapted organizations did not survive in this medium.

Moreover, certain advantageous variations in a given environment can become harmful under other conditions. For example, in a covered with snow medium, a white Fourrure makes it possible not to be seen by its future Proie S or its Prédateur S, but if the medium becomes forester and darker, there will be no more camouflage and the individuals carrying white fur will lose to them selective Avantage. The consequence of this phenomenon is thus that with the wire of the generations, by the natural selection, the characters observed in a population will be more or less adapted to the evolutions of sound ecosystem.

Other examples, at human the Couleur of the skin is an adaptation due to the natural selection, and not to a Bronzage which “would have been fixed” forever in certain populations. In sunny zones the individuals with the clear skin have more risk to develop a Cancer skin because of the rays UV, they are thus handicapped because them Life expectancy is less. In less sunny zones these individuals would be favoured because the sunlight makes it possible the body to produce Vitamine D, and moreover the body saves energy and nutrients by manufacturing less Mélanine, the pigment of the skin.

The factors of the environment which can thus involve a natural selection can be:

Of the factors physico - Chemical S (the Biotope): Climate, occupied medium (Terrestrial, watery, cavernicolous…)
Of other living beings (the Biocénose): presence of Predatory S, Parasite S, microbes, candidates, etc

Convergent adaptations

Origin of the hereditary variations in a population

So that there is selection, still it is necessary that several variations of the same character are present in the population so that the individual more adapted “carries it” on the others. Indeed, in the example above, if the totality of the individuals are identical and carrying the phenotypical variation “white fur”, in the event of climate warming no individual will be able to survive, and the species will die out. In the event of modification of the environment, so that a species survives, it is necessary that it adapts by the natural selection. It is thus essential, that before the change of the medium it has in its center an important genetic diversity.

The genetic information carried by the DNA is relatively unstable

The genetic Diversity in a population of individuals, originates in of the modifications of genetic information in DNA of the cell S. It acts:

of change S specific in the sequence of DNA of genes, or of more important changes like chromosomal rearrangements ;
of genetic recombinations which occur during the transfers of DNA of the Bactéries and at the time of the reproduction sexuée of the Eucaryotes.

One can add to the modifications of the genome referred to above, another source of genetic diversity, are the migration S by which genetic stock in a given population is seen renewed by the arrival of other members of the species carrying a different genetic pool.

The genetic modifications are Aléatoire S: it is not the environment which “dictates” which gene must transfer, but well the Hasard. Therefore one observes in the populations much unsuited variations in the middle of life (for example, the rare genetic diseases). A current error consists in believing that the genetic modifications are a consequence of the natural selection. On the other hand the natural selection has the capacity well to cumulate the adapted innovations, which leads to complex adaptations.

The natural selection acts after the modifications of genetic information

It is thus among the great genetic diversity of the individuals, that then will be selected the phenotypes and the genes most adapted to the environment. To make the demonstration of it one could simply show that the new Phénotype S were present before the change of the medium. This is not always obvious and when well even it would be the case, a mechanism of induction of a change given by the environment is not to exclude. It is thanks to a mathematical easy way that Luria and Delbrück shows that they are well the preexistent changes in a population of bacteria which are selected when one adds a Virus.

The assumption of the acquired features

Without any Genetic knowledge in , Darwin did not have any idea of the molecular mechanisms at the origin of new the character S. Its theory of the natural selection then did not exclude the assumption from the acquired features.

In the initial theory of Darwin such as it exposes it in the Origin of the species , these variations between the individuals find their origin in the fact that the individuals will acquire different characteristics during their life. These acquired features would then be transmitted to their descent and that would explain the variations observed and the evolution of the characteristics of the species. This theory known as of the heredity of the acquired features that Darwin does nothing but use but did not invent, is called Lamarckisme in reference to the Naturaliste Jean-Baptiste Lamarck (1744-1829). To take an example running, the lamarckism would explain thus that the Girafe S have a length Cou because the individuals tighten the neck to reach highest Feuille S of the Arbre S and would end up having a neck very slightly lengthened, consequently their descendants would inherit a lengthened neck. The descendants themselves would lengthen their neck of their alive and would transmit a neck still lengthened to their offspring.

It is generally considered that the theory of the heredity of the acquired features was invalidated by August Weismann at the end of the 19th century. It indeed showed that the mutilations are in general not transmitted, and by extension it was deduced from it that the acquired features are not hereditary. If it is obviously not possible to prove that the heredity of the acquired features does not exist (one can prove an inexistence only for simple processes), there is theoretically a possibility of proving its existence - it would be enough to find of it an example irrefutable -, but this possibility remains very " théorique" would be this only by the definition of the acquired features to take into account. However, the characters Inné S are indeed transmitted during the reproduction but with variations which follow the laws of the Hérédité mendélienne, of the name of their discoverer, Gregor Mendel (1822-1884) whose work on the lines of pea was redécouverts only at the beginning of the 20th century.

Natural selection in genetics of the populations

Convergence between the theory darwinienne and the theory of heredity will then give birth during the Années 1930 to the Génétique of the populations, in particular thanks to theoretical work of Ronald Fisher. At the same period, thanks to the experiments of Thomas Morgan and Theodosius Dobzhansky on the flies drosophilas, the molecular mechanisms responsible for the phenomena of genetic heredity will start to be identified. One of the major discoveries of biology will be then to show that the genetic Diversité which guarantees the variety of the phenotypes is due to random modifications of the Génotype (change S, genetic recombinations,…) in particular during its transmission of one generation to the other, the time of the reproduction.

Even if it is not the mechanism which had been considered by Darwin in his theory of the natural selection, it does not remain about it less than these processes make it possible to return perfectly account of the natural selection within the framework of what is regarded as the central theory of modern biology, the synthetic Théorie of the evolution or neo-darwinist synthesis which establishes the link between the mechanisms on the level of the molecular genetics and the phenomena of evolution on a population scale.

Thus the natural selection can " mesurer" thanks to statistical calculations.

See also: Genetic of the populations, selective Value, Fitness

Scientifically shown cases of natural selection

It appears today obvious that any body having a defined function, for example the fin of fish, is an adaptation to a medium and the result of a natural selection. However the scientific demonstration must, it, to pass by the description of a correlation quantified between the variations of a hereditary feature and those of a precise parameter of the environment. Among the most famous examples, one can quote:

industrial melanism of the Moth of the birch in England: in this species of butterfly S, the proportion of clear individuals decreased because of pollution which blackened surfaces of the tree trunks on which they were posed. Indeed they were more visible for their predatory. The dark moths which existed before pollution became majority. And then the phenomenon was reversed when polluting industries gradually disappeared.
the Finches of Galapagos: the episodes of Sécheresse were followed by a rarefaction of the soft Graine S and thus by an increase in the size of the Bec of the finches enabling them to break the shell of remaining seeds, harder.
natural selection at the Bacterium S of resistances to the Virus Bacteriophage S.A. highlighted by the Experiment of Luria and Delbrück. They indeed showed for the first time that the changes preexist to the selection and that they are quite random.

Natural selection in the mankind

The natural selection takes also effect in the human species :

the capacity in the adult to digest the Lactose Lait was selected in the human populations originating in Europe of north where one raises cattle for his milk, but not in other populations where this food is absent.
the persistence of a Genetic disease as the Drépanocytose is due to the fact that the Allèle responsible for the disease confers also a selective Avantage by also increasing resistance to the parasite responsible for the Paludisme.

Relation between natural selection and human activities

The man can also involuntarily exert a pressure of selection on certain organizations whose evolution, in return, can be harmful for the economy or the human Santé:

the Resistance to the antibiotics: For example, since 1961 the Bactérie S gilded staphilococca resistant to the méticilline multiplied and make ineffective the treatment by this Antibiotique in a great number of cases. These resistances are in the beginning many diseases nosocomiales, in hospital medium.
the Insecticidal resistance of the locusts pilgrims to the S: As in the preceding example, the massive use of insecticide for éradiquer the locusts resulted in a greater resistance. Indeed, the individuals survivant with the insecticidal treatment can generate several thousands of descendants in some generations, that is to say in a few years, which themselves inherit this capacity of resistance. The elimination of this new population then requires a treatment even more aggressive for the ecosystem.

Natural selection, Coévolution and competition

In the preceding examples, they are species evolving/moving with the liking of the human technical improvements but this phenomenon can be also observed in the biological interactions between two species. A very studied example of such a Coévolution is the Parasitisme of laying at the cuckoos. In these species, the relative lays his egg S in the Nid of other birds. As of its birth, the young cuckoo expels eggs present in order to be the only one to profit from the care lavished by the parents of the species host thus misled. Among the parasitized species, some evolved/moved of the antiparasitic strategies, in fact an aptitude to distinguish eggs from cuckoo of their own eggs. That created a Pression of selection for certain species of cuckoo which evolved/moved the shape of Mimétisme of eggs so that those resemble surprisingly eggs of their hosts. In their turn, the parasitized species (e.g., the Shrike flayer) developed increased capacities of Discrimination their own eggs of mimetic eggs of the cuckoo, capacity which is absent at species not or less parasitized.

Such phenomena of Coévolution are frequently observed in the cases of Parasitisme but sometimes also in certain cases of interspecific competition or the intraspecific framework competition of the sexual Sélection. The coévolution inter-sexes are often observed in answer to the sexual selection post-copulatoire: for example, in certain species of birds and invertebrates, the Pénis of the males have a helicoid form which functions like a aspergillum eliminating the seed from the other males and enabling them to deposit their clean Gamète S with deepest of the Vagin of the females with which they couple in order to make sure paternity of the offspring; in these same species, one observes an increase proportional in the size of the vagina with a morphology all in sinuosities which thwarts the reproductive strategies of the males.

Theory of the red queen -->

Artificial selection

The adjective natural is opposed at Darwin to the concept of artificial selection known and practiced since a few thousands of years by the stockbreeders. Indeed domestic livestock or species of crop plants (Pink Cows, dogs, …) constitutes as many variations “ monstrueuses ” absent in nature. They are the fruit of the slow selection of interesting individuals (for the outputs, or from the point of view Esthétique) by the stockbreeders and the farmers (see selective breeding of the animals). It is this observation which made it possible Darwin to put forth the assumption of a selection operated by nature on the wild species.

For example:

the cultivated pink is a change of a wild pink. This change was selected by the horticulturists, it is widespread in the gardens: it is the artificial selection .
In the nature of the cultivated pinks cannot reproduce, it is the natural selection .

Selection artificial, in spite of its intense pressure (elimination of any parent which does not answer the criteria of the choice), does not arrive, after thousand-year-old practices, to give birth to from new species. The races are not insulated and can hybrider without loss or lowers fruitfulness. Domestication and the culture reveal the limits, rather narrow between which the species varies without running of danger, but they do not print an evolutionary movement with the species which they relate to.

Ecological selection and sexual selection

The selection darwinienne is pressed on two joint mechanisms. The first is the ecological Sélection (or selection of survival ) the second is the sexual Sélection . In the general public, this last aspect of sexual selection is often ignored and one identifies the natural selection with the selection of survival. However it is an error because these two mechanisms are well with work in the alive world.

The ecological Selection or selection of survival more specifically indicates the mechanism which makes evolve/move the species under the pressure " externe" environment or " intern" intraspecific competition. Indeed, it rests on the idea that to be able to reproduce, it is initially necessary to survive. This type of selection thus supports the individuals able to escape or to protect themselves from predatory but also to resist the parasite S: it is the interspecific competition. There exists also an intraspecific competition: individuals of the same species being in competition between them to find Ressource S in the environment, that they are nutritive preys or other resources not like shelters (Terrier, Nid,…). Lastly, there are factors known as abiotic which select the individuals the best able ones to resist the environment biotopic, in the ic conditions Climat, etc

The sexual Sélection is a phenomenon which takes place with a stage different from the life of the individual. It indicates the fact that there is also a competition within each species to reach to the sexual partners within the framework of the sexuée Reproduction. This aspect of the theory was fully developed by Darwin in his work entitled the Descent of the Man. Within the framework of the sexual selection, it thus will occur a competition intra-sex, between the individuals of the same sex, but also inter-sex, between the sexes (individuals of a sex having to choose with which individual of the other sex they will be coupled). The sexual selection thus makes it possible to explain characters or behaviors which penalize survival when they are analyzed apart from the reproductive context, like the tail of the Paon, the wood of the mégacéros.

Pressure of selection

Retrospectively, the successive modifications during the generations of the populations can seem directed, as if these modifications were " tirées" or " poussées" in a certain direction. For example, while following the observations of Darwin on the finches of Galapagos, one can observe that certain species seem to follow a tendency towards a widening of the Bec which becomes increasingly massive whereas at other species of finches, the tendency is rather towards a refinement of the nozzle.

This phenomenon which appears as an apparent tendency in the evolution of one or more species received the name of Pression of selection. These pressures of selection “are directed” by the pressures known as interior with the species (sexual Sélection, intraspecific competition) and the pressures known as external with the species (limitation of the resources, modifications of the Environnement, Prédateur S, parasite S…), in short, all that influences the survival and the reproduction of the individuals.

The pressures of selection are differently exerted from one species with the other or of an ecological medium with another, even of a subpopulation of individuals to another. Thus it can occur within the same species a divergence if two subpopulations are subjected to slightly different pressures of selection. These two populations will evolve to different forms which one calls Morphe S and if the phenomenon continues in time one can lead to the formation of two distinct species, it is sympatric speciation. The two species then occupy of the ecological niches sufficiently distinct so that they do not enter directly any more in competition one with the other and follow " then; trajectoires" evolutionary different in answer to the specific pressures of selection to which they are subjected.

The natural selection allows the appearance of complex biological adaptations

The alive systems seem complex very and are adaptations so pushed to a medium that the human ones find there a source of technical innovations and industrial (for example, the fasteners scratch or Velcro, industries pharmaceutical, and chemical). to see: Bionics.

This complexity could be born without the capacity only with the natural selection to accumulate “the good” innovations génétiques :

Each evolutionary innovation appears in a random way. The natural selection supports then each one of these small " sauts" evolutionary (has, then ab, then ABC… then abcde). It thus allows the appearance of increasingly thorough adaptations (abcde). Indeed, if the character (A) had not been selected, the character (abcde) would never have appeared. Because (c) depends on (A). A complex character, like a Enzyme, results from an accumulation of innovations selected successively, and not of simple independent appearances, with the Hasard of the genetic innovations (even if some " sauts" evolutionary can be more or less important or gradual, to see punctuated balance). Thus the natural selection does not make only support the adaptations more complexes ; it allows also their appearance.

That is valid only if the natural selection takes place in a continuous way, which is possible by an intraspecific competition, that Malthus and Darwin consider inevitable in a population. Indeed the living beings have a tendency natural and universal to reproduce in greater number than with the former generation.

The simple innovations due randomly on some generations are not enough to give an account of the complexity of the living beings and their adaptation to their medium. One needs the natural selection to accumulate the small innovations and to come to a body as complex as the eye of mammal, for example.

That can be an answer to criticisms of some néo- creationnists, which affirm that alive systems (Enzyme S…) are too complex and harmonious so that their appearance is due only to random changes, and that thus according to them it would not have had evolution.

A proven example: selection of the locusts pilgrims resistant to an insecticide

In Africa sahélienne, clouds of Criquets pilgrims devour the cultures regularly. This agricultural disaster can involved a Famine. A swarm of locusts is composed of several billion individuals.

To fight against this plague, the farmers use a Insecticide massively. The effect is immediately: almost all the locusts die. However, a negligible part of the locusts have a genetic immunity against insecticide: they survive. These survivors go reproduirent themselves between them quickly (a female locust can lay to 40 eggs). All the descendants of these locusts have immunity against the insectiside.

In a few times, a new swarm form east starts to devastate the cultures. The farmers again use the insectiside to kill the locusts, but this time, it does not function. Only the increase in the amount or the use of another insectiside will make it possible to stop the cloud of locusts. Thus, of a cycle " formation of the cloud of locusts/selection by the insectiside/reproduction of the survivants" set up, making the insects increasingly resistant to the insectisides.

Unfortunately, the simultaneous use of insectisides different to amounts increasingly more important, ends up becoming dangerous for the man, the cattle and the other animal species.

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Limits of the natural selection to explain the evolution of the human Line

There is not any doubt that, like all the other animal species, the mankind is the product of the evolution and thus of the natural selection. For example, one can think that the bipédie offered in the past such a selective advantage to the individuals able to move upright that the genes associated with this mode with Locomotion were spread in all the human population.

There remains nevertheless difficult to rebuild the detail of the evolutionary history of our species and in particular to identify which exact factors and which precise processes could intervene in the human evolution (e.g., sexual Sélection, selection of group, cultural selection, genetic Dérive…) In certain cases, it is nevertheless possible to identify the pressures of selection and the adaptation S resulting from the natural selection in the human populations. One of the most documented examples is the capacity of resistance to the Paludisme. Indeed, the individuals carrying a gene involving an anomaly of their blood cells resist better the parasite which causes this disease. On the other hand, their children run the risk to suffer from Drépanocytose if they inherit this gene of the two parents. The selective Avantage provides by resistance to the paludism thus makes it possible to explain why in the human populations where this parasite is endemic (Africa) is maintained the allele of a gene which can involve a relatively serious disease.

One of the attempts décriées to apply the theory darwinienne to the mankind was the use which it was made of the Sociobiologie developed by E.O. Wilson to explain the behavior of the ultra-social species (Ant S, Termite S, Bee S,…). Indeed, even if it is true that one of the characteristics of the human being (and also of others Primate S) is its social lifestyle very , the theory of Wilson requires also a mode of reproduction and social organization very particular known as Eusocialité, very different from what one observes at the human ones. As Wilson of it himself defends, it is thus absurd to want to directly apply the conclusions of the work led to these species to the mankind. However certain theoretical tools developed initially within the framework of the sociobiology can appear perfectly relevant for the study of the man.

The major challenge of the Paléoanthropologie remains nevertheless to manage to a theoretical framework to explain the human evolution by means of mechanisms richer than the only natural selection. However the importance of phenomena like the Culture, the sexual Selection, the genetic Dérive remains difficult to evaluate: Thus, even within the framework of the modern theories of the evolution, that one calls neodarwinism or synthetic Théorie of the evolution, the evolutionists endeavor to reserve a special place with the man, given that if its body evolved/moved, it remains that what makes the human one escapes the laws of the evolution.

A recent example of such a difficulty relates to the role of the selection of group. Whereas this mechanism which " support the survival of the group to the detriment of the survival of the individu" was very criticized in the animal evolution. It seems that one of the characteristics of the mankind is that precisely, of the phenomena of multilevel selection could play a big role during its evolution and in particular in the evolution of its Psychologie.

Natural selection, behavior and Culture

Any behavior has a genetic and hereditary component. It was shown that the environment could act on the evolution of a hereditary and innate behavior, in certain animals.

As for the Culture which is not transmitted by the DNA, but by the training, it can also be prone to a selection. For example, if I have a behavior which brings satisfaction to me, like getting dressed with the mode, I will reproduce it and I will teach it or me will be imitated. And conversely, this behavior will not be transmitted, if that does not give satisfaction. The theory of memetic emitted by Richard Dawkins, indicates these entities, which one calls Even S, like basic elements of the selection which the culture undergoes, as well as are the genes for the evolution of the alive one.

Other mechanisms of the evolution

When the Fréquence S of the certain hereditary variations change only because of the Hasard, one speaks about drift, even (if the group is very reduced) of effect founder. These characters must be relatively neutral for the natural selection (there is neither favors, nor selective disadvantage). If the same evolution occurs in a way repeated in the same medium during the generations, it is not the drift, but one can speak about selection.

Universal dimension of the natural selection

Within the framework of this theory, all Système in which these the first three principles would be observed would give place to a phenomenon of evolution by natural selection. In the alive world, the hereditary transmission of the information Génétique, which obeys these three principles, thus results in an evolution from the Espèce S by natural selection. However, from a theoretical point of view, the evolution by natural selection does not depend on the precise nature of the mechanisms which allow the appearance of variations, the hereditary transmission and the translation of hereditary information in phenotypical characters. The fact that Darwin himself was unaware of until the existence of genes illustrates the distinction well that it is advisable to make between the theoretical framework of the selection darwinienne and its observable demonstrations in the terrestrial ecosystems.

Consequently, the phenomena évolutionnaires observed in the alive world could completely appear in other systems which would implement the three basic principles of the selection darwinienne. It is for example, the assumption made in Exobiologie according to which forms of extraterrestrial Vie S could be appeared on the basis of mechanism fundamental different from those that one knows of terrestrial biology. Within such forms of life evolving/moving by natural selection, one should thus observe phenomena similar to those which one knows on Ground: Adaptation, Coévolution, sexuée Reproduction… more adaptationnists of the biologists of the evolution (as Simon Conway Morris) thus proposed that the environmental constraints are sufficiently strong and similar so that the extraterrestrial forms of life should present important evolutionary convergences with the terrestrial life, among which the presence of Yeux, the Eusocialité, or of the capacities Cognitive S complexes.

More close to us, the application of the principles of the natural selection to the human cultural sphere gave place to the Mémétique which seeks to explain the variations, the transmission, and the stabilization of the cultural phenomena by analogy with the alive species. Within this theoretical framework, the Even S are the units of selection, or réplicateurs, of the cultural phenomena. The selection intervenes on the same ones according to their capacity with " to survive " i.e. to persist in the spirit of the individuals and their capacity with " to reproduce " , i.e. to pass from an individual to another by the Imitation, the Communication, the Teaching, etc With each Reproduction, same thus can " to transfer " : through being told, the same history for example will be deformed, it is the principle of the Bush telegraph. Thus, in spite of the notable differences between nature of the biological and cultural réplicateurs, some Analogie S can be considered: Coévolution (including between gene and even) or complex formation of very. The relevance of the application of the theory darwinienne to the cultural phenomena remains nevertheless very discussed.

Finally one can also quote the example of the algorithms évolutionnaires used in the field of the optimization in Ingénierie. Those make it possible to seek a solution with a Problème given by putting in competition a population of potential solutions whose only best is preserved to be recombined and give rise to a new generation of solutions. Since in this method the selection is the result of a human intervention, this case rather raises of the artificial Sélection.

See too

Internal bonds

Critical Anthropology
of the Darwinism
Selection (biology), evolutionary Radiation
selective Breeding of the animals

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