home

What is called natural selection. Natural selection for dummies

Natural selection is a process originally defined by Charles Darwin as leading to the survival and preferential reproduction of individuals who are more adapted to given environmental conditions and have useful hereditary traits. In accordance with Darwin's theory and the modern synthetic theory of evolution, the main material for natural selection are random hereditary changes - recombination of genotypes, mutations and their combinations.

In the absence of a sexual process, natural selection leads to an increase in the proportion of a given genotype in the next generation. However, natural selection is "blind" in the sense that it "evaluates" not genotypes, but phenotypes, and the preferential transfer to the next generation of genes of an individual possessing useful signs, occurs regardless of whether these traits are inherited.

There are different classifications of forms of selection. A classification based on the nature of the influence of selection forms on the variability of a trait in a population is widely used.

driving selection- a form of natural selection that operates under a directed change in conditions external environment. Described by Darwin and Wallace. In this case, individuals with traits that deviate in a certain direction from the average value receive advantages. At the same time, other variations of the trait (its deviations in the opposite direction from the average value) are subjected to negative selection. As a result, a shift occurs in the population from generation to generation. medium size sign in a particular direction. In this case, the pressure of driving selection must correspond to the adaptive capabilities of the population and the rate of mutational changes (otherwise, environmental pressure can lead to extinction).

An example of the action of motive selection is "industrial melanism" in insects. "Industrial melanism" is a sharp increase in the proportion of melanistic (having a dark color) individuals in those populations of insects (for example, butterflies) that live in industrial areas. Due to industrial impact, tree trunks darkened significantly, and light lichens also died, which made light butterflies more visible to birds, and dark ones worse. In the 20th century, in a number of areas, the proportion of dark-colored butterflies in some well-studied populations of the birch moth in England reached 95%, while the first dark-colored butterfly (morfa carbonaria) was captured in 1848.

Driving selection is carried out when changing environment or adaptation to new conditions with the expansion of the range. It preserves hereditary changes in a certain direction, shifting the rate of reaction accordingly. For example, during the development of the soil as a habitat in various unrelated groups of animals, the limbs turned into burrowing ones.

Stabilizing selection- a form of natural selection, in which its action is directed against individuals with extreme deviations from the average norm, in favor of individuals with an average severity of the trait. The concept of stabilizing selection was introduced into science and analyzed by I.I. Schmalhausen.

Many examples of the action of stabilizing selection in nature have been described. For example, at first glance it seems that individuals with maximum fecundity should make the greatest contribution to the gene pool of the next generation. However, observations of natural populations of birds and mammals show that this is not the case. The more chicks or cubs in the nest, the more difficult it is to feed them, the smaller and weaker each of them. As a result, individuals with average fecundity turn out to be the most adapted.

Selection in favor of averages has been found for a variety of traits. In mammals, very low and very high birth weight newborns are more likely to die at birth or in the first weeks of life than middle weight newborns. Accounting for the size of the wings of sparrows that died after a storm in the 50s near Leningrad showed that most of them had too small or too large wings. And in this case, the average individuals turned out to be the most adapted.

Disruptive (tearing) selection- a form of natural selection, in which conditions favor two or more extreme variants (directions) of variability, but do not favor the intermediate, average state of the trait. As a result, several new forms may appear from one initial one. Darwin described the operation of disruptive selection, believing that it underlies divergence, although he could not provide evidence for its existence in nature. Disruptive selection contributes to the emergence and maintenance of population polymorphism, and in some cases can cause speciation.

One of the possible situations in nature in which disruptive selection comes into play is when a polymorphic population occupies a heterogeneous habitat. Wherein different forms adapt to different ecological niches or sub-niches.

An example of disruptive selection is the formation of two races in a large rattle in hay meadows. Under normal conditions, the flowering and seed ripening periods of this plant cover the whole summer. But in hay meadows, seeds are produced mainly by those plants that have time to bloom and ripen either before the mowing period, or bloom at the end of summer, after mowing. As a result, two races of the rattle are formed - early and late flowering.

Disruptive selection was carried out artificially in experiments with Drosophila. The selection was carried out according to the number of setae, leaving only individuals with small and large quantity bristles. As a result, from about the 30th generation, the two lines diverged very strongly, despite the fact that the flies continued to interbreed with each other, exchanging genes. In a number of other experiments (with plants), intensive crossing prevented the effective action of disruptive selection.

sexual selection This is natural selection for success in reproduction. The survival of organisms is an important but not the only component of natural selection. Another important component is attractiveness to members of the opposite sex. Darwin called this phenomenon sexual selection. “This form of selection is determined not by the struggle for existence in the relations of organic beings with one another or with external conditions, but by rivalry between individuals of one sex, usually males, for the possession of individuals of the other sex. Traits that reduce the viability of their carriers can emerge and spread if the advantages they provide in breeding success are significantly greater than their disadvantages for survival. Two main hypotheses about the mechanisms of sexual selection have been proposed. According to the “good genes” hypothesis, the female “reasons” in the following way: “If this male, despite his bright plumage and long tail, somehow managed not to die in the clutches of a predator and live to puberty, then, therefore, he has good genes that allowed him to do this. So, he should be chosen as a father for his children: he will pass on his good genes to them. By choosing bright males, females choose good genes for their offspring. According to the “attractive sons” hypothesis, the logic of female selection is somewhat different. If bright males, for whatever reason, are attractive to females, then it is worth choosing a bright father for your future sons, because his sons will inherit the bright color genes and will be attractive to females in the next generation. Thus, a positive feedback occurs, which leads to the fact that from generation to generation the brightness of the plumage of males is more and more enhanced. The process goes on increasing until it reaches the limit of viability. In choosing males, females are no more and no less logical than in all other behavior. When an animal feels thirsty, it does not reason that it should drink water in order to restore the water-salt balance in the body - it goes to the watering hole because it feels thirsty. In the same way, females, choosing bright males, follow their instincts - they like bright tails. All those who instinctively prompted a different behavior, all of them left no offspring. Thus, we discussed not the logic of females, but the logic of the struggle for existence and natural selection - a blind and automatic process that, acting constantly from generation to generation, has formed all that amazing variety of forms, colors and instincts that we observe in the world of wildlife. .

From Wikipedia, the free encyclopedia

Natural selection- the main evolutionary process, as a result of which the number of individuals with maximum fitness (the most favorable traits) increases in the population, while the number of individuals with unfavorable traits decreases. In the light of the modern synthetic theory of evolution, natural selection is seen as main reason development of adaptations , speciation and origin of supraspecific taxa . Natural selection is the only known cause of adaptations, but not the only cause of evolution. Non-adaptive causes include genetic drift, gene flow, and mutations.

The term "Natural Selection" was popularized by Charles Darwin, comparing this process with artificial selection modern form which is the selection . The idea of comparing artificial and natural selection is that in nature the selection of the most “successful”, “best” organisms also takes place, but in this case it is not a person who acts as an “appraiser” of the usefulness of properties, but the environment. In addition, the material for both natural and artificial selection are small hereditary changes that accumulate from generation to generation.

Mechanism of natural selection

In the process of natural selection, mutations are fixed that increase the fitness of organisms. Natural selection is often referred to as a "self-evident" mechanism because it follows from simple facts such as:

Organisms produce more offspring than can survive;
In the population of these organisms, there is hereditary variability;
Organisms that have different genetic traits have different survival rates and ability to reproduce.

The central concept of the concept of natural selection is the fitness of organisms. Fitness is defined as the ability of an organism to survive and reproduce, which determines the size of its genetic contribution to the next generation. However, the main thing in determining fitness is not total number descendants, and the number of descendants with a given genotype (relative fitness) . For example, if the offspring of a successful and rapidly reproducing organism are weak and do not reproduce well, then the genetic contribution and, accordingly, the fitness of this organism will be low.

Natural selection for traits that can vary over some range of values (such as the size of an organism) can be divided into three types:

Directed Selection- changes in the average value of the trait over time, for example, an increase in body size;
Disruptive selection- selection for the extreme values of the trait and against the average values, for example, large and small body sizes;
Stabilizing selection- selection against the extreme values of the trait, which leads to a decrease in the variance of the trait.

A special case of natural selection is sexual selection, whose substrate is any trait that increases the success of mating by increasing the attractiveness of an individual for potential partners. Traits that have evolved through sexual selection are particularly evident in the males of certain animal species. Traits such as large horns, bright colors, on the one hand, can attract predators and reduce the survival rate of males, and on the other hand, this is balanced by the reproductive success of males with similar pronounced traits.

Selection can operate at various levels of organization such as genes, cells, individual organisms, groups of organisms, and species. Moreover, selection can simultaneously act on different levels. Selection at levels above the individual, such as group selection, can lead to cooperation (see Evolution#Cooperation).

Forms of natural selection

There are different classifications of forms of selection. A classification based on the nature of the influence of selection forms on the variability of a trait in a population is widely used.

driving selection

driving selection- a form of natural selection that operates under directed changing environmental conditions. Described by Darwin and Wallace. In this case, individuals with traits that deviate in a certain direction from the average value receive advantages. At the same time, other variations of the trait (its deviations in the opposite direction from the average value) are subjected to negative selection. As a result, in the population from generation to generation, there is a shift in the average value of the trait in a certain direction. In this case, the pressure of driving selection must correspond to the adaptive capabilities of the population and the rate of mutational changes (otherwise, environmental pressure can lead to extinction).

An example of the action of motive selection is "industrial melanism" in insects. "Industrial melanism" is a sharp increase in the proportion of melanistic (having a dark color) individuals in those populations of insects (for example, butterflies) that live in industrial areas. Due to industrial impact, tree trunks darkened significantly, and light lichens also died, which made light butterflies more visible to birds, and dark ones worse. In the 20th century, in a number of areas, the proportion of dark-colored butterflies in some well-studied populations of the birch moth in England reached 95%, while for the first time a dark butterfly ( Morfa carbonaria) was captured in 1848.

Driving selection is carried out when the environment changes or adapts to new conditions with the expansion of the range. It preserves hereditary changes in a certain direction, moving the reaction rate accordingly. For example, during the development of the soil as a habitat in various unrelated groups of animals, the limbs turned into burrowing ones.

Stabilizing selection

Disruptive selection

One of the possible situations in nature in which disruptive selection comes into play is when a polymorphic population occupies a heterogeneous habitat. At the same time, different forms adapt to different ecological niches or subniches.

Disruptive selection was carried out artificially in experiments with Drosophila. The selection was carried out according to the number of setae, leaving only individuals with a small and large number of setae. As a result, from about the 30th generation, the two lines diverged very strongly, despite the fact that the flies continued to interbreed with each other, exchanging genes. In a number of other experiments (with plants), intensive crossing prevented the effective action of disruptive selection.

sexual selection

Two hypotheses about the mechanisms of sexual selection are common.

According to the “good genes” hypothesis, the female “argues” as follows: “If this male, despite the bright plumage and long tail, managed not to die in the clutches of a predator and survive to puberty, then he has good genes that allowed him to do this. Therefore, he should be chosen as the father of his children: he will pass on his good genes to them. By choosing bright males, females choose good genes for their offspring.
According to the “attractive sons” hypothesis, the logic of female selection is somewhat different. If bright males, for whatever reason, are attractive to females, it is worth choosing a bright father for your future sons, because his sons will inherit the bright color genes and will be attractive to females in the next generation. Thus, a positive feedback occurs, which leads to the fact that from generation to generation the brightness of the plumage of males increases more and more. The process goes on increasing until it reaches the limit of viability.

When choosing males, females do not think about the reasons for their behavior. When an animal feels thirsty, it does not reason that it should drink water in order to restore the water-salt balance in the body - it goes to the watering hole because it feels thirsty. In the same way, females, choosing bright males, follow their instincts - they like bright tails. Those who instinctively prompted a different behavior did not leave offspring. The logic of the struggle for existence and natural selection is the logic of a blind and automatic process that, acting constantly from generation to generation, has formed that amazing variety of forms, colors and instincts that we observe in the world of wildlife.

Selection methods: positive and negative selection

There are two forms of artificial selection: Positive and Clipping (negative) selection.

Positive selection increases the number of individuals in the population that have useful traits that increase the viability of the species as a whole.

Cut-off selection culls out from the population the vast majority of individuals that carry traits that sharply reduce viability under given environmental conditions. With the help of cut-off selection, strongly harmful alleles are removed from the population. Also, individuals with chromosomal rearrangements and a set of chromosomes that sharply disrupt normal work genetic apparatus.

The role of natural selection in evolution

In the example of the worker ant, we have an insect extremely different from its parents, yet absolutely barren and therefore unable to transmit from generation to generation acquired modifications of structure or instincts. Can be set good question- How far is it possible to reconcile this case with the theory of natural selection?
- Origin of Species (1859)

Darwin assumed that selection could be applied not only to the individual organism, but also to the family. He also said that, perhaps, to one degree or another, this can also explain the behavior of people. He turned out to be right, but it was not until the advent of genetics that it became possible to provide a more extended view of this concept. The first outline of the "kind selection theory" was made by the English biologist William Hamilton in 1963, who was the first to propose considering natural selection not only at the level of an individual or a whole family, but also at the level of a gene.

Write a review on the article "Natural Selection"

Notes

, with. 43-47.
, p. 251-252.
OrrHA// Nat Rev Genet. - 2009. - Vol. 10(8). - P. 531-539.
Haldane J// Nature. - 1959. - Vol. 183. - P. 710-713.
Lande R, Arnold SJ The measurement of selection on correlated characters // Evolution. - 1983. - Vol. 37.-P. 1210–26. - DOI:10.2307/2408842.
.
, Chapter 14.
Andersson M, Simmons L// Trends Ecol Evol. - 2001. - Vol. 21(6). - P. 296-302.
Kokko H, Brooks R, McNamara J, Houston A// Proc Biol Sci. - 2002. - Vol. 269. - P. 1331-1340.
Hunt J, Brooks R, Jennions MD, Smith MJ, Bentsen CL, Bussière LF// Nature. - 2004. - Vol. 432. - P. 1024-1027.
Okasha, S. evolution and the Levels of Selection. - Oxford University Press, 2007. - 263 p. - ISBN 0-19-926797-9.
Mayr E// Philos. Trans. R. Soc. Lond., B, Biol. sci. - 1998. - T. 353. - pp. 307–14.
Maynard Smith J// Novartis Found. Symp. - 1998. - T. 213. - pp. 211–217.
Gould SJ, Lloyd EA//Proc. Natl. Acad. sci. U.S.A. - 1999. - T. 96, No. 21. - S. 11904–11909.

Literature

Lua error: attempt to index local "entity" (a nil value).

Links

- article with good famous examples: the color of butterflies, people's resistance to malaria and more
- Chapter 4, Natural Selection
- Modeling for Understanding in Science Education, University of Wisconsin
University of Berkeley education website
Evolution: Education and Outreach





evolutionary processes

Factors of evolution

Population genetics

Origin of life

Historical concepts

Modern theories

Evolution of taxa

An excerpt characterizing Natural selection

“Three times they killed me, three times I was raised from the dead. They stoned me, crucified me... I will rise... rise... rise. Ripped apart my body. The Kingdom of God will be destroyed… I will destroy it three times and raise it up three times,” he shouted, raising and raising his voice. Count Rostopchin suddenly turned as pale as he had turned pale when the crowd rushed at Vereshchagin. He turned away.
“Sh… go quick!” he shouted at the coachman in a trembling voice.
The carriage rushed at all the legs of the horses; but for a long time behind him Count Rostopchin heard a distant, insane, desperate cry, and before his eyes he saw one surprised, frightened, bloody face of a traitor in a fur coat.
No matter how fresh this memory was, Rostopchin now felt that it was deeply, to the point of blood, cut into his heart. He now clearly felt that the bloody trace of this memory would never heal, but that, on the contrary, the further, the more evil, more painful this terrible memory would live in his heart until the end of his life. He heard, it seemed to him now, the sounds of his own words:
“Chop it, you will answer me with your head!” Why did I say those words! Somehow I accidentally said ... I could not say them (he thought): then nothing would have happened. He saw the frightened and then suddenly hardened face of the dragoon who struck him and the look of silent, timid reproach that this boy in a fox coat threw at him ... “But I didn’t do it for myself. I should have done this. La plebe, le traitre… le bien publique,” [Mob, villain… public good.] – he thought.
At the Yauza bridge, the army was still crowding. It was hot. Kutuzov, frowning and dejected, was sitting on a bench near the bridge, playing with his whip on the sand, when a carriage galloped up to him with a noise. A man in a general's uniform, in a hat with a plume, with shifting eyes that were either angry or scared, approached Kutuzov and began to say something to him in French. It was Count Rostopchin. He told Kutuzov that he had come here because Moscow and the capital were no more and there was only one army.
“It would be different if Your Grace had not told me that you would not surrender Moscow without giving a battle: all this would not have happened! - he said.
Kutuzov looked at Rostopchin and, as if not understanding the meaning of the words addressed to him, diligently tried to read something special written at that moment on the face of the person speaking to him. Rastopchin, embarrassed, fell silent. Kutuzov shook his head slightly and, without taking his searching gaze off Rostopchin's face, said softly:
- Yes, I will not give up Moscow without giving a battle.
Whether Kutuzov was thinking about something completely different when he said these words, or on purpose, knowing their meaninglessness, he said them, but Count Rostopchin did not answer and hastily moved away from Kutuzov. And a strange thing! The commander-in-chief of Moscow, the proud Count Rostopchin, took a whip in his hands, went up to the bridge and began shouting to disperse the crowded wagons.

At four o'clock in the afternoon, Murat's troops entered Moscow. In front rode a detachment of Wirtemberg hussars, behind on horseback, with a large retinue, the Neapolitan king himself rode.
Near the middle of the Arbat, near Nikola Yavlenny, Murat stopped, waiting for news from the advance detachment about the situation in the city fortress "le Kremlin".
Around Murat, a small group of people from the residents who remained in Moscow gathered. Everyone looked with timid bewilderment at the strange, long-haired chief adorned with feathers and gold.
- Well, is it himself, or what, their king? Nothing! quiet voices were heard.
The interpreter drove up to a bunch of people.
“Take off your hat… take off your hat,” they started talking in the crowd, addressing each other. The interpreter turned to an old janitor and asked how far it was to the Kremlin? The janitor, listening with bewilderment to the Polish accent alien to him and not recognizing the sounds of the interpreter as Russian, did not understand what was said to him and hid behind the others.
Murat moved up to the interpreter and ordered him to ask where the Russian troops were. One of the Russian people understood what was being asked of him, and several voices suddenly began to answer the interpreter. A French officer from the advance detachment rode up to Murat and reported that the gates to the fortress were sealed up and that there was probably an ambush there.
- Good, - said Murat and, turning to one of the gentlemen of his retinue, he ordered four light guns to be advanced and fired at the gates.
Artillery trotted out from behind the column following Murat and drove along the Arbat. Having descended to the end of Vzdvizhenka, the artillery stopped and lined up on the square. Several French officers disposed of the cannons, placing them, and looked at the Kremlin through a telescope.
In the Kremlin, the bell was heard for Vespers, and this ringing embarrassed the French. They assumed it was a call to arms. Several infantry soldiers ran to the Kutafiev Gate. Logs and plank shields lay in the gates. Two rifle shots rang out from under the gate as soon as the officer with the team began to run up to them. The general, who was standing by the guns, shouted command words to the officer, and the officer with the soldiers ran back.
Three more shots were heard from the gate.
One shot hit a French soldier in the leg, and a strange cry from a few voices was heard from behind the shields. On the faces of the French general, officers and soldiers at the same time, as if on command, the former expression of cheerfulness and calmness was replaced by a stubborn, concentrated expression of readiness for struggle and suffering. For all of them, from the marshal to the last soldier, this place was not Vzdvizhenka, Mokhovaya, Kutafya and Trinity Gates, but it was a new area of a new field, probably a bloody battle. And everyone is ready for this battle. The screams from the gates ceased. The guns were advanced. The gunners blew off their burnt overcoats. The officer commanded "feu!" [fall!], and two whistling sounds of tin cans were heard one after another. Card-shot bullets crackled on the stone of the gate, logs and shields; and two clouds of smoke wavered in the square.
A few moments after the rolling of shots on the stone Kremlin had died down, a strange sound was heard over the heads of the French. A huge flock of jackdaws rose above the walls and, croaking and rustling with thousands of wings, circled in the air. Along with this sound, a lonely human cry was heard at the gate, and from behind the smoke appeared the figure of a man without a hat, in a caftan. Holding a gun, he aimed at the French. Feu! - repeated the artillery officer, and at the same time one rifle and two gun shots were heard. The smoke closed the gate again.
Nothing else moved behind the shields, and the French infantry soldiers with officers went to the gate. There were three wounded and four dead people in the gate. Two men in caftans ran downstairs, along the walls, towards Znamenka.
- Enlevez moi ca, [Take it away,] - said the officer, pointing to the logs and corpses; and the French, having finished off the wounded, threw the corpses down behind the fence. Who these people were, no one knew. “Enlevez moi ca” is only said about them, and they were thrown away and cleaned up afterwards so that they would not stink. One Thiers dedicated several eloquent lines to their memory: “Ces miserables avaient envahi la citadelle sacree, s "etaient empares des fusils de l" arsenal, et tiraient (ces miserables) sur les Francais. On en sabra quelques "uns et on purgea le Kremlin de leur presence. [These unfortunates filled the sacred fortress, took possession of the guns of the arsenal and fired at the French. Some of them were chopped down with sabers, and the Kremlin was cleared of their presence.]
Murat was informed that the path had been cleared. The French entered the gate and began to camp on the Senate Square. Soldiers threw chairs out of the windows of the senate into the square and laid out fires.
Other detachments passed through the Kremlin and were stationed along Maroseyka, Lubyanka, and Pokrovka. Still others were located along Vzdvizhenka, Znamenka, Nikolskaya, Tverskaya. Everywhere, not finding owners, the French were placed not like in the city in apartments, but like in a camp located in the city.
Although ragged, hungry, exhausted and reduced to 1/3 of their former strength, the French soldiers entered Moscow in orderly order. It was an exhausted, exhausted, but still fighting and formidable army. But this was an army only until the moment when the soldiers of this army dispersed to their quarters. As soon as the people of the regiments began to disperse to empty and rich houses, the army was forever destroyed and not residents and not soldiers were formed, but something in between, called marauders. When, after five weeks, the same people left Moscow, they no longer constituted an army. It was a crowd of marauders, each of whom was carrying or carrying with him a bunch of things that he thought were valuable and needed. The goal of each of these people when leaving Moscow was not, as before, to win, but only to keep what they had acquired. Like that monkey who, having put his hand into the narrow throat of a jug and seized a handful of nuts, does not open his fist so as not to lose what he has seized, and this destroys himself, the French, when leaving Moscow, obviously had to die due to the fact that they were dragging with loot, but it was as impossible for him to give up this loot as it is impossible for a monkey to unclench a handful of nuts. Ten minutes after the entry of each French regiment into some quarter of Moscow, not a single soldier and officer remained. In the windows of the houses one could see people in overcoats and boots, laughingly pacing around the rooms; in the cellars, in the cellars, the same people were in charge with provisions; in the yards, the same people unlocked or beat off the gates of sheds and stables; fires were laid out in the kitchens, with rolled up hands they baked, kneaded and boiled, frightened, made laugh and caressed women and children. And there were many of these people everywhere, both in shops and in houses; but the troops were gone.
On the same day, order after order was given by the French commanders to forbid the troops to disperse around the city, to strictly prohibit the violence of the inhabitants and looting, to make a general roll call that very evening; but no matter what measures. the people who had previously made up the army spread out over the rich, abundant in amenities and supplies, empty city. Just as a hungry herd marches in a heap across a bare field, but immediately disperses irresistibly as soon as it attacks rich pastures, so the army dispersed irresistibly throughout a rich city.
There were no inhabitants in Moscow, and the soldiers, like water into the sand, soaked into it and spread like an unstoppable star in all directions from the Kremlin, into which they entered first of all. The cavalry soldiers, entering the merchant's house left with all the good and finding stalls not only for their horses, but also superfluous, nevertheless went side by side to occupy another house, which seemed better to them. Many occupied several houses, writing with chalk what he was doing, and arguing and even fighting with other teams. Not having time to fit yet, the soldiers ran out into the street to inspect the city and, according to the rumor that everything was abandoned, rushed to where they could pick up valuable things for free. The commanders went to stop the soldiers and themselves were involuntarily involved in the same actions. There were shops with carriages in Karetny Ryad, and the generals crowded there, choosing carriages and carriages for themselves. The remaining residents invited the chiefs to their place, hoping that they would be protected from robbery. There was an abyss of wealth, and there was no end in sight; everywhere, around the place that the French had occupied, there were still unexplored, unoccupied places in which, as it seemed to the French, there were even more riches. And Moscow sucked them further and further into itself. Exactly as due to the fact that water is poured onto dry land, water and dry land disappear; in the same way, due to the fact that the hungry army entered the plentiful, empty city, the army was destroyed, and the abundant city was destroyed; and there was dirt, fires and looting.

The French attributed the fire of Moscow to au patriotisme feroce de Rastopchine [Rastopchin's wild patriotism]; Russians - to the fanaticism of the French. In essence, there were no such reasons and could not be. Moscow burned down due to the fact that it was placed in such conditions under which any wooden city must burn down, regardless of whether or not there are one hundred and thirty bad fire pipes in the city. Moscow had to burn down due to the fact that the inhabitants left it, and just as inevitably as a pile of shavings should catch fire, on which sparks of fire would fall for several days. A wooden city, in which there are fires almost every day in the summer with residents, owners of houses and with the police, cannot help but burn when there are no inhabitants in it, but troops live, smoking pipes, laying fires on Senate Square from Senate chairs and cooking themselves two times a day. In peacetime, it is necessary for troops to settle down in apartments in villages in a certain area, and the number of fires in this area immediately increases. To what extent should the probability of fires increase in an empty wooden city in which a foreign army is stationed? Le patriotisme feroce de Rastopchine and the savagery of the French are not to blame for anything here. Moscow caught fire from pipes, from kitchens, from bonfires, from the slovenliness of enemy soldiers, residents - not the owners of houses. If there were arson (which is very doubtful, because there was no reason for anyone to set fire, and, in any case, troublesome and dangerous), then arson cannot be taken as a reason, since without arson it would be the same.
No matter how flattering it was for the French to blame the atrocities of Rastopchin and for the Russians to blame the villain Bonaparte or then to put the heroic torch into the hands of their people, one cannot help but see that there could not be such a direct cause of the fire, because Moscow had to burn down, as every village, factory should burn down , any house from which the owners will come out and into which they will be allowed to host and cook their own porridge of strangers. Moscow is burned down by the inhabitants, it is true; but not by those inhabitants who remained in it, but by those who left it. Moscow, occupied by the enemy, did not remain intact, like Berlin, Vienna and other cities, only due to the fact that its inhabitants did not bring bread of salt and keys to the French, but left it.

On the day of September 2, the French invasion, spreading like a star across Moscow, reached the quarter in which Pierre now lived, only in the evening.
Pierre was in a state close to insanity after the last two, solitary and unusually spent days. His whole being was seized by one obsessive thought. He himself did not know how and when, but this thought now took possession of him so that he did not remember anything from the past, did not understand anything from the present; and everything he saw and heard happened before him as in a dream.
Pierre left his home only in order to get rid of the complex confusion of the demands of life that had seized him, and which he, in his then state, but was able to unravel. He went to Iosif Alekseevich's apartment under the pretext of going through the books and papers of the deceased, only because he was seeking solace from life's anxiety - and with the memory of Iosif Alekseevich, a world of eternal, calm and solemn thoughts was associated in his soul, completely opposite to the disturbing confusion in which he felt drawn in. He was looking for a quiet refuge and indeed found it in the office of Joseph Alekseevich. When, in the dead silence of the office, he sat down, leaning on his hands, over a dusty desk of the deceased, in his imagination, calmly and significantly, one after another, memories began to appear last days, in particular the Battle of Borodino and that indefinable feeling for him of his insignificance and deceit in comparison with the truth, simplicity and strength of that category of people who were imprinted in his soul under the name they. When Gerasim woke him from his reverie, Pierre had the idea that he would take part in the alleged - as he knew - people's defense of Moscow. And for this purpose, he immediately asked Gerasim to get him a caftan and a pistol and announced to him his intention, hiding his name, to stay in the house of Joseph Alekseevich. Then, in the course of the first solitary and idle day spent (Pierre tried several times and could not stop his attention on Masonic manuscripts), several times he vaguely imagined the thought that had previously come about the cabalistic meaning of his name in connection with the name of Bonaparte; but this thought that he, l "Russe Besuhof, is destined to put an end to the power of the beast, came to him only as one of the dreams that run through his imagination for no reason and without a trace.
When, having bought a caftan (with the aim of only participating in the people's defense of Moscow), Pierre met the Rostovs and Natasha told him: “Are you staying? Oh, how good it is! - the thought flashed through his head that it would really be good, even if they took Moscow, he would stay in it and fulfill what was predetermined for him.
The next day, with one thought not to feel sorry for himself and not to lag behind them in anything, he went with the people beyond the Trekhgornaya outpost. But when he returned home, convinced that Moscow would not be defended, he suddenly felt that what had previously seemed to him only a possibility had now become a necessity and inevitability. He had to, hiding his name, stay in Moscow, meet Napoleon and kill him in order to either die or stop the misfortune of all of Europe, which, according to Pierre, came from Napoleon alone.
Pierre knew all the details of the attempt on the life of a German student by Bonaparte in Vienna in 1809 and knew that this student was shot. And the danger to which he exposed his life in the fulfillment of his intention excited him even more.
Two equally strong feelings irresistibly attracted Pierre to his intention. The first was the feeling of the need for sacrifice and suffering in the consciousness of general misfortune, that feeling, as a result of which he went to Mozhaisk on the 25th and drove into the heat of battle, now ran away from his house and, instead of the usual luxury and comforts of life, slept without undressing on hard couch and ate the same meal with Gerasim; the other was that indefinite, exclusively Russian feeling of contempt for everything conventional, artificial, human, for everything that is considered by most people to be the highest good of the world. For the first time, Pierre experienced this strange and charming feeling in the Sloboda Palace, when he suddenly felt that wealth, and power, and life, everything that people arrange and cherish with such diligence - if all this is worth something, then only for the pleasure with which all this can be thrown.
It was that feeling as a result of which a hunter-recruit drinks the last penny, a drunken man breaks mirrors and glasses without any apparent reason and knowing that it would cost him his last money; that feeling, as a result of which a person, committing (in the vulgar sense) crazy deeds, as if tries his personal power and strength, declaring the presence of a higher, standing outside human conditions, judgment on life.
From the very day that Pierre first experienced this feeling in the Sloboda Palace, he was incessantly under his influence, but now he only found him complete satisfaction. In addition, at the present moment, Pierre was supported in his intention and deprived of the opportunity to renounce him by what he had already done along the way. And his flight from home, and his caftan, and the pistol, and his statement to Rostov that he was staying in Moscow - everything would not only lose its meaning, but all this would be contemptible and ridiculous (to which Pierre was sensitive), if after all this, like the others, he left Moscow.

main historical factor. organic development. peace; consists in the fact that of the nascent individuals, only those survive and, most importantly, produce offspring, to-rye have at least a subtle, but still significant advantage over other individuals - a more perfect adaptability to the conditions of life. E.'s opening about. like ch. patterns of biology. development is the most important merit of Darwin and is the core of Darwinism. The most important prerequisites for E. o. are variability and the struggle for existence between individuals both within a given species and between individuals belonging to different species. As a result of the action of these factors, not all individuals survive to adulthood and, therefore, give offspring. The winners in the struggle for existence are the individuals that are best adapted to the given conditions and therefore with great success oppose enemies and competitors and the unfavorable conditions of nature. They reproduce more intensively, leave more offspring than less adapted ones. Finally, necessary condition success E. o. is the inheritance of new useful features of the organization of living beings (see. Heredity). The gradual accumulation and strengthening of these traits in subsequent generations and the disappearance of intermediate forms (since the struggle for existence is the sharper, the closer the organisms are to each other, since they have similar needs for the means of subsistence) lead to an ever greater increase in differences between organisms, to a divergence signs - the so-called. divergence. As a result, new forms of organisms arise: first ecotypes, varieties, subspecies, and then species. Thus, species and speciation occur due to E. o. the fittest and E. o. as a whole leads to the improvement of forms, to the strengthening of their vital activity. The appearance of new forms, better adapted to the given conditions of existence and especially more perfectly organized, conceals in itself the germ of the death of forms living in the same conditions, but inferior to new forms in terms of adaptability to given environmental conditions or in terms of the level of organization. E. o., as the main. the law of evolution of species, characterized, therefore, by qualities, a peculiar dependence of the individual, variability and general evolution. development. Individual. differences, in themselves causally determined by the processes of vital activity of individual organisms, in relation to evolution. processes appear as random. E. o. discovers their necessity by checking whether they will be adapted. meaning. Thus, E. o. there is a regularity in which the dialectic of necessity and chance manifests itself as specific. biological content. evolution. Engels specifically emphasizes this dialectic. the basis of Darwin's theory of E. o.: "Darwin, in his epoch-making work, proceeds from the broadest factual basis based on chance. It is precisely the endless random differences of individuals within certain types ... force him to question ... the concept of a species in its former metaphysical rigidity and immutability ... Chance overturns the understanding of necessity that existed until now" ("Dialectics of Nature", 1955, pp. 174–75). E. o. The non-mechanical character of biological causality is clearly seen from such cases of adaptation, in which the traits developed in the course of natural evolution are useful for the species, although they are harmful to the individual. For example, the sting of a bee is designed so that when it is used, the insect dies. However, the ability to sting is useful for the preservation of the species. The specific nature of biological causality determines the objective content of the concept of biological expediency, which is a natural result of E. o In this way, the theory of natural theory completely refutes teleology.This theory is essentially built on the recognition of the role of the contradiction of random individual variability and general biological species adaptation as the driving principle of speciation. These contradictions are resolved by victory and b. or m. the rapid spread of new forms and the displacement of old ones. This process sometimes proceeds so rapidly and violently that one can speak of upheavals in the history of this group. The resolution of contradictions leads to the creation of new, more advanced devices, and, thus, as a result of the action of E. o. the organization of living beings acquires features related. expediency, it turns out to be harmonious in structure and functions, adapted to the changing conditions of life. Occurrence by E. about. devices that are useful not only in that biotope, which is occupied by populations of the species in the crust. time, but also beyond it, i.e. devices of wide significance, opening up the possibility of capture by the descendants of this species of a new ecological. zone, leads to evolution. progress. Acquisition of such adaptations, to-rye are valuable and useful hl. arr. within the framework of certain specific conditions of existence, does not open prospects for going beyond this ecological. areas. Such adaptations, especially if they are associated with strictly defined conditions of existence, lead to the specialization of living beings. However, it must be sharply contrasted with specialization and progress. Facts from the history of organic of the world testify to the presence of a certain kind of "interpenetration" of progress and specialization. These facts also show that progress in the sense of a general rise in organization is not harmonious. development of all systems of functions and organs. It is associated with the loss of certain signs that are necessary and useful in certain conditions of existence, and, consequently, with a certain regression. Thus, the theory of E. o. considers regress dialectically as a moment, a form of biological. progress. Creative, creating new forms, the role of E. o. is especially clearly visible from observations, for example, over a rattle plant. On nature. rattle has a self-opening box and wind-blown winged seeds. In rye crops, a form of rattle grows with a non-opening box and wingless seeds, which prevents the elimination of the rattle from crops (the box is threshed together with rye, but the seeds are not blown away by the wind when winnowing). It turned out that the degree of wing development in the seed pods varies greatly (from normal wings to complete winglessness). E. o. acted in the direction of eliminating winged forms (they were blown away by the wind when winnowing), which, in the end, led to the formation of a wingless form of rattle in cultivated crops. The value of E. o. like a creative the force of speciation decisively refutes the interpretation of it as a factor, the action of which is limited only to the elimination of forms that are not sufficiently adapted to the ecological data. conditions. Lit.: Engels F., Dialectics of Nature, Moscow, 1955; Darwin Ch., The origin of species by means of natural selection, Soch., v. 3, M.–L., 1939; its the same, Pet changes and cultivated plants, ibid., vol. 4, M.–L., 1951; Lysenko T. D., Natural selection and intraspecific competition, Minsk, 1951; ?Miryazev K. ?., Fav. soch., vol. 2, M., 1957; Gabunia L.K., On the issue of progressive development in the phylogenesis of mammals, in: Tr. department of paleobiology of the Academy of Sciences of Georgia. SSR, [vol.] 2, Tb., 1954; Golinevich P. N., Overpopulation and the struggle for existence, "Problems of Philosophy", 1956, No 4; Davitashvili L. Sh., Essays on the history of the doctrine of evolution. progress, M., 1956; Gilyarov M.S., Problems of modern. ecology and theory of natures. selection, "Successful modern biol.", 1959, v. 48, no. 3(6) (named after bibliography); Wallace A. R., Natural selection, St. Petersburg, 1878; Schmidt G. ?., Natural. selection as general and non-specific. factor of evolutionary progress, "Izv. AN SSSR. Ser. biol.", 1959, No 6 (named after bibliogr.); Frolov I. T., About causality and expediency in living nature, M., 1961; Plate L., Selectionsprinzip und Probleme der Artbildung. Ein Handbuch des Darwinismus, 3 Aufl., Lpz., 1908; L'H?ritier Ph., G?n?tique et ?volution, P., 1934; D'Ancona U., The struggle for existence, Leiden, 1954; Fisher R.?., The genetic theory of natural selection, N. Y., . L. Gabunia. Tbilisi.

Natural selection is the main, leading, guiding factor in evolution, underlying the theory of Ch. Darwin. All other factors of evolution are random, only natural selection has a direction (in the direction of adapting organisms to environmental conditions).

Definition: selective survival and reproduction of the fittest organisms.

Creative role: selecting useful traits, natural selection creates new ones.

Efficiency: the more different mutations in the population (the higher the heterozygosity of the population), the greater the efficiency of natural selection, the faster evolution proceeds.

Forms:

Stabilizing - acts in constant conditions, selects the average manifestations of the trait, preserves the traits of the species (coelacanth fish coelacanth)
Driving - acts in changing conditions, selects the extreme manifestations of a trait (deviations), leads to a change in traits (birch moth)
Sexual - competition for a sexual partner.
Breaking - selects two extreme forms.

Consequences of natural selection:

Evolution (change, complication of organisms)
Emergence of new species (increase in the number [diversity] of species)
The adaptation of organisms to environmental conditions. Any fit is relative., i.e. adapts the body to only one specific conditions.

Choose the one most correct option. The basis of natural selection is
1) mutation process
2) speciation
3) biological progress
4) relative fitness

Answer

Choose one, the most correct option. What are the consequences of stabilizing selection
1) preservation of old species
2) change in reaction rate
3) the emergence of new species
4) preservation of individuals with altered traits

Answer

Choose one, the most correct option. In the process of evolution, a creative role is played by
1) natural selection
2) artificial selection
3) modification variability
4) mutational variability

Answer

Choose three options. What are the characteristics of motive selection?
1) operates under relatively constant living conditions
2) eliminates individuals with an average value of the trait
3) promotes the reproduction of individuals with a modified genotype
4) preserves individuals with deviations from the average values of the trait
5) preserves individuals with the established norm of the reaction of the trait
6) contributes to the appearance of mutations in the population

Answer

Choose three features that characterize the driving form of natural selection
1) provides the appearance of a new species
2) manifests itself in changing environmental conditions
3) the adaptability of individuals to the original environment is improved
4) individuals with a deviation from the norm are culled
5) the number of individuals with the average value of the trait increases
6) individuals with new traits are preserved

Answer

Choose one, the most correct option. The starting material for natural selection is
1) struggle for existence
2) mutational variability
3) changing the habitat of organisms
4) adaptation of organisms to the environment

Answer

Choose one, the most correct option. The starting material for natural selection is
1) modification variability
2) hereditary variability
3) the struggle of individuals for the conditions of survival
4) adaptability of populations to the environment

Answer

Choose three options. The stabilizing form of natural selection is manifested in
1) constant environmental conditions
2) change in the average reaction rate
3) the preservation of adapted individuals in the original habitat
4) culling of individuals with deviations from the norm
5) saving individuals with mutations
6) preservation of individuals with new phenotypes

Answer

Choose one, the most correct option. The effectiveness of natural selection decreases when
1) the occurrence of recessive mutations
2) an increase in homozygous individuals in the population
3) change in the norm of the reaction of a sign
4) increase in the number of species in the ecosystem

Answer

Choose one, the most correct option. In arid conditions, in the process of evolution, plants with pubescent leaves were formed due to the action of
1) relative variability

3) natural selection
4) artificial selection

Answer

Choose one, the most correct option. Insect pests acquire resistance to pesticides over time as a result of
1) high fecundity
2) modification variability
3) preservation of mutations by natural selection
4) artificial selection

Answer

Choose one, the most correct option. The material for artificial selection is
1) genetic code
2) population
3) genetic drift
4) mutation

Answer

Choose one, the most correct option. Are the following statements about the forms of natural selection correct? A) The emergence of resistance to pesticides in insect pests of agricultural plants is an example of a stabilizing form of natural selection. B) Driving selection contributes to an increase in the number of individuals of a species with an average value of a trait
1) only A is true
2) only B is true
3) both statements are correct
4) both judgments are wrong

Answer

Establish a correspondence between the results of the action of natural selection and its forms: 1) stabilizing, 2) moving, 3) disruptive (tearing). Write the numbers 1, 2 and 3 in the correct order.
A) development of resistance to antibiotics in bacteria
B) The existence of fast and slow growing predatory fish in the same lake
C) Similar structure of the organs of vision in chordates
D) The emergence of flippers in waterfowl mammals
E) Selection of newborn mammals with an average weight
E) Preservation of phenotypes with extreme deviations within one population

Answer

1. Establish a correspondence between the characteristic of natural selection and its form: 1) driving, 2) stabilizing. Write the numbers 1 and 2 in the correct order.
A) preserves the mean value of the feature
B) contributes to adaptation to changing environmental conditions
C) retains individuals with a trait that deviates from its average value
D) contributes to an increase in the diversity of organisms
D) contributes to the preservation of species characteristics

Answer

2. Compare the characteristics and forms of natural selection: 1) Driving, 2) Stabilizing. Write the numbers 1 and 2 in the correct order.
A) acts against individuals with extreme values of traits
B) leads to a narrowing of the reaction norm
B) usually operates under constant conditions
D) occurs during the development of new habitats
D) changes the average values of the trait in the population
E) can lead to the emergence of new species

Answer

3. Establish a correspondence between the forms of natural selection and their characteristics: 1) driving, 2) stabilizing. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) operates in changing environmental conditions
B) operates in constant environmental conditions
C) is aimed at maintaining the previously established average value of the trait
D) leads to a shift in the average value of the trait in the population
D) under its action, both an increase in a sign and a weakening can occur

Answer

4. Establish a correspondence between the signs and forms of natural selection: 1) stabilizing, 2) driving. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) forms adaptations to new environmental conditions
B) leads to the formation of new species
B) maintains the average norm of the trait
D) culls individuals with deviations from the average norm of signs
D) increases the heterozygosity of the population

Answer

Establish a correspondence between examples and forms of natural selection, which are illustrated by these examples: 1) driving, 2) stabilizing. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) an increase in the number of dark butterflies in industrial areas compared to light ones
B) the emergence of insect pest resistance to pesticides
C) the preservation of the reptile tuatara living in New Zealand to the present day
D) a decrease in the size of the cephalothorax in crabs living in muddy water
E) in mammals, the mortality of newborns with an average weight is less than with very low or very high
E) the death of winged ancestors and the preservation of insects with reduced wings on islands with strong winds

Answer

Establish a correspondence between the forms of the struggle for existence and examples illustrating them: 1) intraspecific, 2) interspecific. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) fish eat plankton
B) seagulls kill chicks when there are a large number of them
C) capercaillie lekking
D) nosed monkeys try to shout down each other, puffing out huge noses
D) chaga mushroom settles on a birch
E) the main prey of the marten is squirrel

Answer

Analyze the table "Forms of natural selection". For each letter, select the appropriate concept, characteristic and example from the list provided.
1) sexual
2) driving
3) group
4) preservation of organisms with two extreme deviations from the average value of the trait
5) the emergence of a new sign
6) the formation of bacterial resistance to antibiotics
7) preservation of the relict plant species Gingko biloba 8) increase in the number of heterozygous organisms

Answer

The idea of comparing artificial and natural selection is that in nature the selection of the most “successful”, “best” organisms also takes place, but in this case it is not a person who acts as an “appraiser” of the usefulness of properties, but the environment. In addition, the material for both natural and artificial selection are small hereditary changes that accumulate from generation to generation.

Mechanism of natural selection

In the process of natural selection, mutations are fixed that increase the adaptability of organisms to their environment. Natural selection is often referred to as a "self-evident" mechanism because it follows from simple facts such as:

Organisms produce more offspring than can survive;
In the population of these organisms, there is hereditary variability;
Organisms that have different genetic traits have different survival rates and ability to reproduce.

The central concept of the concept of natural selection is the fitness of organisms. Fitness is defined as the ability of an organism to survive and reproduce in its existing environment. This determines the size of his genetic contribution to the next generation. However, the main thing in determining fitness is not the total number of offspring, but the number of offspring with a given genotype (relative fitness). For example, if the offspring of a successful and rapidly reproducing organism are weak and do not reproduce well, then the genetic contribution and, accordingly, the fitness of this organism will be low.

Natural selection for traits that can vary over some range of values (such as the size of an organism) can be divided into three types:

Directed Selection- changes in the average value of the trait over time, for example, an increase in body size;
Disruptive selection- selection for the extreme values of the trait and against the average values, for example, large and small body sizes;
Stabilizing selection- selection against the extreme values of the trait, which leads to a decrease in the variance of the trait.

Selection can operate at various levels of organization such as genes, cells, individual organisms, groups of organisms, and species. Moreover, selection can act simultaneously at different levels. Selection at levels above the individual, such as group selection, can lead to cooperation (see Evolution#Cooperation).

Forms of natural selection

There are different classifications of forms of selection. A classification based on the nature of the influence of selection forms on the variability of a trait in a population is widely used.

driving selection

An example of the action of motive selection is "industrial melanism" in insects. "Industrial melanism" is a sharp increase in the proportion of melanistic (having a dark color) individuals in those populations of insects (for example, butterflies) that live in industrial areas. Due to industrial impact, tree trunks darkened significantly, and light lichens also died, which made light butterflies more visible to birds, and dark ones worse. In the 20th century, in a number of regions, the proportion of dark-colored butterflies in some well-studied populations of the birch-moth in England reached 95%, while for the first time the dark-colored butterfly ( Morfa carbonaria) was captured in 1848.

Driving selection is carried out when the environment changes or adapts to new conditions with the expansion of the range. It preserves hereditary changes in a certain direction, moving the norm of the reaction accordingly. For example, during the development of the soil as a habitat in various unrelated groups of animals, the limbs turned into burrowing ones.

Stabilizing selection

Disruptive selection

Disruptive selection was carried out artificially in experiments with Drosophila. The selection was carried out according to the number of setae, leaving only individuals with a small and large number of setae. As a result, from about the 30th generation, the two lines diverged very strongly, despite the fact that the flies continued to interbreed with each other, exchanging genes. In a number of other experiments (with plants), intensive crossing prevented the effective action of disruptive selection.

sexual selection

Two hypotheses about the mechanisms of sexual selection are common.

According to the “good genes” hypothesis, the female “reasons” as follows: “If this male, despite the bright plumage and long tail, managed not to die in the clutches of a predator and survive to puberty, then he has good genes that allowed him to do this . Therefore, he should be chosen as the father of his children: he will pass on his good genes to them. By choosing bright males, females choose good genes for their offspring.
According to the “attractive sons” hypothesis, the logic of female selection is somewhat different. If bright males, for whatever reason, are attractive to females, it is worth choosing a bright father for your future sons, because his sons will inherit the bright color genes and will be attractive to females in the next generation. Thus, a positive feedback occurs, which leads to the fact that from generation to generation the brightness of the plumage of males increases more and more. The process goes on increasing until it reaches the limit of viability.

Selection methods: positive and negative selection

There are two forms of artificial selection: Positive and Clipping (negative) selection.

Positive selection increases the number of individuals in the population that have useful traits that increase the viability of the species as a whole.

The role of natural selection in evolution

In the example of the worker ant, we have an insect extremely different from its parents, yet absolutely barren and therefore unable to transmit from generation to generation acquired modifications of structure or instincts. One can ask a good question - to what extent is it possible to reconcile this case with the theory of natural selection?
- Origin of Species (1859)

Notes

, with. 43-47.
, p. 251-252.
Orr H.A. Fitness and its role in evolutionary genetics // Nature Reviews Genetics. - 2009. - Vol. 10, no. 8. - P. 531-539. - DOI:10.1038/nrg2603. - PMID 19546856 .
Haldane J.B.S. The theory of natural selection today // Nature. - 1959. - Vol. 183, no. 4663. - P. 710-713. - PMID 13644170 .
Lande R., Arnold S. J. The measurement of selection on correlated characters // Evolution. - 1983. - Vol. 37, no. 6. - P. 1210-1226. -

What else to read

What does "wear a hat on a butch" mean? In domestic places not so remote, all prisoners are divided into four prison castes (they are also called ...

How and how much you can drink coffee from chicory If doctors categorically forbid you to drink coffee, then do not despair! Chicory will be an excellent substitute for your favorite ...

What foods promote serotonin synthesis? We have all heard of the miraculous hormone of happiness. It is found in chocolate and bananas, after which the mood ...

What is called natural selection. Natural selection for dummies

Mechanism of natural selection

Forms of natural selection

driving selection

Stabilizing selection

Disruptive selection

sexual selection

Selection methods: positive and negative selection

The role of natural selection in evolution

see also

Write a review on the article "Natural Selection"

Notes

Literature

Links

An excerpt characterizing Natural selection

Mechanism of natural selection

Forms of natural selection

driving selection

Stabilizing selection

Disruptive selection

sexual selection

Selection methods: positive and negative selection

The role of natural selection in evolution

see also

Notes

What else to read

THE LAST NOTES

What is called natural selection. Natural selection for dummies

Mechanism of natural selection

Forms of natural selection

driving selection

Stabilizing selection

Disruptive selection

sexual selection

Selection methods: positive and negative selection

The role of natural selection in evolution

see also

Write a review on the article "Natural Selection"

Notes

Literature

Links

An excerpt characterizing Natural selection

Mechanism of natural selection

Forms of natural selection

driving selection

Stabilizing selection

Disruptive selection

sexual selection

Selection methods: positive and negative selection

The role of natural selection in evolution

see also

Notes

What else to read

THE LAST NOTES

Categories