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Prerequisites for the emergence of the theory

Problems in the original Darwinian theory that led to its loss of popularity

Soon after its emergence, the theory of natural selection was subjected to constructive criticism from its principal opponents, and some of its elements - from its supporters. Most of the counterarguments against Darwinism over the first quarter of a century of its existence were collected in a two-volume monograph "Darwinism: A Critical Study" by the Russian philosopher and publicist N. Ya. Danilevsky. Nobel Laureate 1908 I. I. Mechnikov, agreeing with Darwin on the leading role of natural selection, did not share Darwin's assessment of the importance of overpopulation for evolution. The founder of the theory highest value gave the counterargument of the English engineer F. Jenkin, who, with the light hand of Darwin, received the name "Jenkin's nightmare".

As a result, in late XIX At the beginning of the 20th century, most biologists accepted the concept of evolution, but few believed that natural selection was its main driving force. Neo-Lamarckism, the theory of orthogenesis and the combination of Mendelian genetics with the mutation theory of Korzhinsky-De Vries began to dominate. The English biologist Julian Huxley dubbed this situation " an eclipse of Darwinism en en".

Contradictions between genetics and Darwinism

Despite the fact that the discreteness of heredity discovered by Mendel eliminated the significant difficulties associated with the "Jenkin's nightmare", many geneticists rejected the Darwinian theory of evolution.

The emergence and development of STE

The synthetic theory in its current form was formed as a result of rethinking a number of provisions of classical Darwinism from the standpoint of genetics at the beginning of the 20th century. After the rediscovery of Mendel's laws (in 1901), the evidence of the discrete nature of heredity, and especially after the creation of theoretical population genetics by the works of Ronald Fisher, John B. S. Haldane, Jr. and Sewell Wright, Darwin's teachings acquired a solid genetic foundation.

It is believed that the evolutionary act took place when selection retained a gene combination that was not typical for the previous history of the species. As a result, for the implementation of evolution, the presence of three processes is necessary:

1. mutational, generating new variants of genes with a small phenotypic expression;
2. recombination, creating new phenotypes of individuals;
3. selection, which determines the compliance of these phenotypes with given living conditions or growth.

All supporters of the synthetic theory admit participation in evolution of three the listed factors.

An important prerequisite for the emergence new theory evolution was the book of the English geneticist, mathematician and biochemist J. B. S. Haldane, Jr., who published it in 1932 under the title “ The causes of evolution". Haldane, creating the genetics of individual development, immediately included a new science in solving the problems of macroevolution.

Major evolutionary innovations very often arise on the basis of neoteny (preservation of juvenile traits in an adult organism). Neoteny Haldane explained the origin of man ("naked ape"), the evolution of such large taxa as graptolites and foraminifers. In 1933, Chetverikov's teacher N. K. Koltsov showed that neoteny is widespread in the animal kingdom and plays an important role in progressive evolution. It leads to morphological simplification, while maintaining the richness of the genotype.

In almost all historical and scientific models, 1937 was called the year of the emergence of STE - this year the book of the Russian-American geneticist and entomologist-systematist F. G. Dobzhansky " Genetics and the Origin of Species". The success of Dobzhansky's book was determined by the fact that he was both a naturalist and an experimental geneticist. “The dual specialization of Dobzhansky allowed him to be the first to throw a solid bridge from the camp of experimental biologists to the camp of naturalists” (E. Mair). For the first time, the most important concept of "isolating mechanisms of evolution" was formulated - those reproductive barriers that separate the gene pool of one species from the gene pools of other species. Dobzhansky introduced the half-forgotten Hardy-Weinberg equation into wide scientific circulation. He also introduced the “S. Wright effect” into naturalistic material, believing that microgeographic races arise under the influence of random changes in gene frequencies in small isolates, that is, in an adaptive-neutral way.

In the English-language literature, among the creators of STE, the names of F. Dobrzhansky, J. Huxley, E. Mayr, B. Rensch, J. Stebbins are most often mentioned. This, of course, is far from full list. Only among the Russian scientists, at least, one should name I. I. Shmalgauzen, N. V. Timofeev-Resovsky, G. F. Gauze, N. P. Dubinin, A. L. Takhtadzhyan. Of the British scientists, the role of J. B. S. Haldane, Jr., D. Lack, C. Waddington, G. de Beer is great. German historians mention the names of E. Baur, W. Zimmermann, W. Ludwig, G. Heberer and others among the active creators of STE.

The main provisions of STE, their historical formation and development

In the 1930s and 1940s, a broad synthesis of genetics and Darwinism quickly took place. Genetic ideas penetrated systematics, paleontology, embryology, and biogeography. The term "modern" or "evolutionary synthesis" comes from the title of the book by J. Huxley " "(1942). The expression "synthetic theory of evolution" in the exact application to this theory was first used by J. Simpson in 1949.

• the elementary unit of evolution is the local population;
• the material for evolution is mutational and recombination variability;
• natural selection is seen as the main reason for the development of adaptations, speciation, and the origin of supraspecific taxa;
• drift of genes and the founder principle are the reasons for the formation of neutral traits;
• a species is a system of populations reproductively isolated from populations of other species, and each species is ecologically isolated;
• speciation consists in the emergence of genetic isolating mechanisms and occurs predominantly under conditions of geographic isolation.

Thus, the synthetic theory of evolution can be characterized as the theory of organic evolution by natural selection of traits determined genetically.

The activity of the American creators of STE was so high that they quickly created an international society for the study of evolution, which in 1946 became the founder of the journal evolution". Magazine " american naturalist” returned to the publication of works on evolutionary topics, with an emphasis on the synthesis of genetics, experimental and field biology. As a result of numerous and diverse studies, the main provisions of STE have not only been successfully tested, but have also been modified and supplemented with new ideas.

In 1942, the German-American ornithologist and zoogeographer E. Mair published the book Systematics and Origin of Species, in which the concept of a polytypic species and the genetic-geographical model of speciation were consistently developed. Mayr proposed the founder's principle, which he formulated in its final form in 1954. If genetic drift, as a rule, provides a causal explanation for the formation of neutral traits in the temporal dimension, then the founder principle in the spatial dimension.

After the publication of the works of Dobzhansky and Mayr, taxonomists received a genetic explanation for what they had long been sure of: subspecies and closely related species differ to a large extent in adaptive-neutral characters.

None of the works on STE can be compared with the mentioned book by the English experimental biologist and naturalist J. Huxley " Evolution: The Modern synthesis"(1942). Huxley's work surpasses even the book of Darwin himself in terms of the volume of the analyzed material and the breadth of the problematics. Huxley for many years kept in mind all directions in the development of evolutionary thought, closely followed the development of related sciences and had personal experience experimental geneticist. The prominent historian of biology Provin assessed Huxley's work as follows: “Evolution. Modern Synthesis" was the most comprehensive on the topic and documents than other works on this topic. Haldane and Dobzhansky's books were written mainly for geneticists, Mayr for taxonomists, and Simpson for paleontologists. Huxley's book became the dominant force in the evolutionary synthesis."

In terms of volume, Huxley's book had no equal (645 pages). But the most interesting thing is that all the main ideas set forth in the book were written out very clearly by Huxley on 20 pages back in 1936, when he sent an article to the British Association for the Advancement of Science entitled " natural selection and evolutionary progress". In this aspect, none of the publications on evolutionary theory that appeared in the 1930s and 40s can compare with Huxley's article. Feeling well the spirit of the times, Huxley wrote: “At present, biology is in a phase of synthesis. Until that time, the new disciplines worked in isolation. There is now a tendency towards unification which is more fruitful than the old one-sided views of evolution" (1936). Back in the writings of the 1920s, Huxley showed that the inheritance of acquired traits is impossible; natural selection acts as a factor in evolution and as a factor in the stabilization of populations and species (evolutionary stasis); natural selection acts on small and large mutations; geographic isolation is the most important condition for speciation. The apparent purpose in evolution is explained by mutations and natural selection.

The main points of Huxley's 1936 article can be summarized very briefly in this form:

1. Mutations and natural selection are complementary processes that alone cannot create directed evolutionary change.
2. Selection in natural populations most often acts not on individual genes, but on complexes of genes. Mutations cannot be beneficial or harmful, but their selective value varies in different environments. The mechanism of action of selection depends on the external and genotypic environment, and the vector of its action on the phenotypic manifestation of mutations.
3. Reproductive isolation is the main criterion indicating the completion of speciation. Speciation can be continuous and linear, continuous and divergent, sharp and convergent.
4. Gradualism and pan-adaptationism are not universal characteristics of the evolutionary process. Most land plants are characterized by discontinuity and the rapid formation of new species. Widespread species evolve gradually, while small isolates evolve discontinuously and not always adaptively. Discontinuous speciation is based on specific genetic mechanisms (hybridization, polyploidy, chromosomal aberrations). Species and supraspecific taxa, as a rule, differ in adaptive-neutral characters. The main directions of the evolutionary process (progress, specialization) are a compromise between adaptability and neutrality.
5. Potentially preadaptive mutations are widespread in natural populations. This type of mutation plays essential role in macroevolution, especially during periods of dramatic environmental change.
6. The concept of gene action rates explains the evolutionary role of heterochrony and allometry. Synthesizing the problems of genetics with the concept of recapitulation leads to an explanation of the rapid evolution of species at the dead end of specialization. Through neoteny, the "rejuvenation" of the taxon occurs, and it acquires new rates of evolution. An analysis of the relationship between ontogenesis and phylogeny makes it possible to discover epigenetic mechanisms for the direction of evolution.
7. In the process of progressive evolution, selection acts to improve the organization. The main result of evolution was the appearance of man. With the advent of man, a great biological evolution develops into a psychosocial one. Evolutionary theory is one of the sciences that studies the formation and development of human society. It creates the foundation for understanding the nature of man and his future.

A wide synthesis of data from comparative anatomy, embryology, biogeography, paleontology with the principles of genetics was carried out in the works of I. I. Schmalhausen (1939), A. L. Takhtadzhyan (1943), J. Simpson (1944), B. Rensch (1947). Out of these studies grew the theory of macroevolution. Only Simpson's book was published on English language and during the period of wide expansion of American biology, it is most often mentioned alone among the fundamental works.

The last statement, reflecting the essence of neutralism, is in no way consistent with the ideology of the synthetic theory of evolution, which goes back to the concept of A. Weismann's germ plasm, from which the development of the corpuscular theory of heredity began. According to Weisman's views, all factors of development and growth are located in germ cells; accordingly, in order to change the organism, it is necessary and sufficient to change the germ plasm, that is, the genes. As a result, the theory of neutrality inherits the concept of genetic drift, generated by neo-Darwinism, but subsequently abandoned by it.

The latest theoretical developments have appeared, which made it possible to bring STE even closer to real-life facts and phenomena that its original version could not explain. The milestones achieved by evolutionary biology to date differ from the previously presented postulates of STE:

The postulate of the population as the smallest evolving unit remains valid. However, a huge number of organisms without a sexual process remains outside the scope of this definition of a population, and this is seen as a significant incompleteness of the synthetic theory of evolution.

Natural selection is not the only driver of evolution.

Evolution is not always divergent.

Evolution does not have to be gradual. It is possible that in some cases individual macroevolutionary events may also have a sudden character.

Macroevolution can go both through microevolution and along its own paths.

Recognizing the insufficiency of the reproductive criterion of a species, biologists still cannot offer a universal species definition for both forms with a sexual process and for agamic forms.

The random nature of mutational variability does not contradict the possibility of the existence of a certain canalization of evolutionary paths that arises as a result of the past history of the species. The theory of nomogenesis or evolution based on regularities, put forward in 1922-1923, should also become widely known. L.S. Berg. His daughter, R. L. Berg, considered the problem of randomness and regularity in evolution and came to the conclusion that "evolution proceeds along permitted paths" of evolution as a whole is satisfactorily explained by this theory.

As one of the critics general provisions The synthetic theory of evolution can be brought to its approach to explaining secondary similarities, that is, close morphological and functional features that were not inherited, but arose independently in phylogenetically distant branches of the evolution of organisms.

According to neo-Darwinism, all signs of living beings are completely determined by the genotype and the nature of selection. Therefore, parallelism (secondary similarity of related beings) is explained by the fact that organisms have inherited a large number of identical genes from their recent ancestor, and the origin of convergent traits is entirely attributed to the action of selection. However, it is well known that similarities that develop in fairly distant lineages are often maladaptive and therefore cannot be plausibly explained either by natural selection or by common inheritance. The independent occurrence of identical genes and their combinations is obviously excluded, since mutations and recombination are random processes.

In response to such criticism, supporters of the synthetic theory may object that the ideas of S. S. Chetverikov and R. Fisher about the complete randomness of mutations have now been significantly revised. Mutations are random only in relation to the environment, but not to the existing organization of the genome. Now it seems quite natural that different sections of DNA have different stability; accordingly, some mutations will occur more often, others less frequently. In addition, the set of nucleotides is very limited. Consequently, there is a possibility of independent (and, moreover, completely random, causeless) occurrence of identical mutations (up to the synthesis by distant species of one and similar proteins that could not have been inherited by them from a common ancestor). These and other factors cause significant secondary recurrence in the structure of DNA and may explain the origin of non-adaptive similarity from the standpoint of neo-Darwinism as a random selection from a limited number of possibilities.

Another example - the criticism of STE by proponents of mutational evolution - is related to the concept of punctualism or "punctuated equilibrium". Punctualism is based on a simple paleontological observation: the duration of stasis is several orders of magnitude longer than the duration of the transition from one phenotypic state to another. Judging by the available data, this rule is generally true for the entire fossil history of multicellular animals and has a sufficient amount of evidence.

The authors of punctualism oppose their view to gradualism - Darwin's idea of ​​gradual evolution through small changes - and consider punctuated equilibrium a sufficient reason to reject the entire synthetic theory. Such a radical approach caused a discussion around the concept of punctuated equilibrium, which has been going on for 30 years. Most authors agree that there is only a quantitative difference between the concepts of “gradual” and “intermittent”: a long process appears as an instantaneous event, being depicted on a compressed time scale. Therefore, punctualism and gradualism should be considered as additional concepts. In addition, supporters of the synthetic theory rightly note that punctuated equilibrium does not create additional difficulties for them: long-term stasis can be explained by the action of stabilizing selection (under the influence of stable, relatively unchanged conditions of existence), and rapid change can be explained by S. Wright's theory of shifting equilibrium for small populations , with abrupt changes in the conditions of existence and / or in the case of the passage of a species or any of its isolated parts, populations, through the bottle neck ISBN 5-03-001432-2

Schmalhausen I. I. Ways and laws of the evolutionary process. - 2nd ed. - M., 1983. - (Ser. Selected works).

Simpson G.G. The major features of evolution. - 3rd ed - New York, 1953.

Fisher R.A. The genetic theory of natural selection. - 2nd ed. - New York, 1958.

Huxley J. evolution. The modern synthesis. - 2nd ed. - London, 1963.

We know about Anaximander's scheme from the historian of the 1st century BC. e. Diodorus Siculus. In his presentation, when the young Earth was illuminated by the Sun, its surface first hardened, and then fermented, rotting appeared, covered with thin shells. All kinds of animal breeds were born in these shells. Man, on the other hand, seems to have arisen from a fish or an animal similar to a fish. Although original, Anaximander's reasoning is purely speculative and unsupported by observation. Another ancient thinker, Xenophanes, paid more attention to observations. So, he identified the fossils that he found in the mountains with the prints of ancient plants and animals: laurel, shells of mollusks, fish, seals. From this, he concluded that the land once sank into the sea, bringing death to land animals and people, and turned into mud, and when it rose, the imprints dried up. Heraclitus, despite the impregnation of his metaphysics with the idea continuous development and eternal becoming, did not create any evolutionary concepts. Although some authors still refer to him as the first evolutionists.

The only author from whom the idea of ​​a gradual change of organisms can be found was Plato. In his dialogue "The State" he put forward the infamous proposal: to improve the breed of people by selecting the best representatives. Without a doubt, this proposal was based on known fact selection of producers in animal husbandry. In the modern era, the unwarranted application of these ideas to human society developed into the doctrine of eugenics, which underlies the racial policy of the Third Reich.

Medieval and Renaissance

With the rise in the level of scientific knowledge after the "ages of darkness" of the early Middle Ages, evolutionary ideas again begin to slip in the writings of scientists, theologians and philosophers. Albert the Great first noted the spontaneous variability of plants, leading to the emergence of new species. The examples once given by Theophrastus he characterized as transmutation one kind to another. The term itself was apparently taken by him from alchemy. In the 16th century, fossil organisms were rediscovered, but only by the end of the 17th century did the idea that this was not a “game of nature”, not stones in the form of bones or shells, but the remains of ancient animals and plants, finally captured the minds. In the work of the year "Noah's Ark, Its Shape and Capacity", Johann Buteo gave calculations that showed that the ark could not contain all kinds of known animals. In the year Bernard Palissy arranged an exhibition of fossils in Paris, where he first compared them with living ones. In the year he published in print the idea that since everything in nature is "in eternal transmutation", many fossil remains of fish and mollusks belong to extinct types.

Evolutionary ideas of modern times

As we can see, the matter did not go beyond the expression of disparate ideas about the variability of species. This same trend continued with the advent of the New Age. So Francis Bacon, the politician and philosopher, suggested that species could change, accumulating the "errors of nature". This thesis again, as in the case of Empedocles, echoes the principle of natural selection, but about general theory no word yet. Oddly enough, but the first book on evolution can be considered a treatise by Matthew Hale (Eng. Matthew Hale) "The Primitive Origination of Mankind Considered and Examined According to the Light of Nature". This may seem strange just because Hale himself was not a naturalist and even a philosopher, he was a lawyer, theologian and financier, and wrote his treatise during a forced vacation on his estate. In it, he wrote that one should not assume that all species were created in their modern form, on the contrary, only archetypes were created, and all the diversity of life developed from them under the influence of numerous circumstances. Hale also anticipates many of the controversies about chance that have arisen since the establishment of Darwinism. In the same treatise, the term "evolution" in the biological sense is mentioned for the first time.

Ideas of limited evolutionism like those of Hale arose constantly, and can be found in the writings of John Ray, Robert Hooke, Gottfried Leibniz, and even in the later work of Carl Linnaeus. They are expressed more clearly by Georges Louis Buffon. Observing the precipitation from the water, he came to the conclusion that 6 thousand years, which were assigned to the history of the Earth by natural theology, are not enough for the formation of sedimentary rocks. The age of the Earth calculated by Buffon was 75 thousand years. Describing the species of animals and plants, Buffon noted that along with useful features, they also have those to which it is impossible to attribute any utility. This again contradicted natural theology, which held that every hair on an animal's body was created for its benefit, or for man's benefit. Buffon came to the conclusion that this contradiction can be eliminated by accepting the creation of only a general plan, which varies in specific incarnations. Having applied Leibniz's "law of continuity" to taxonomy, he spoke out in a year against the existence of discrete species, considering species to be the fruit of the fantasy of taxonomists (this can be seen as the origins of his ongoing polemic with Linnaeus and the antipathy of these scientists to each other).

Lamarck's theory

The move to combine transformist and systematic approaches was made by the naturalist and philosopher Jean Baptiste Lamarck. As a proponent of species change and a deist, he recognized the Creator and believed that the Supreme Creator created only matter and nature; all other inanimate and living objects arose from matter under the influence of nature. Lamarck emphasized that "all living bodies come from one another, and not by successive development from previous embryos." Thus, he opposed the concept of preformism as autogenetic, and his follower Etienne Geoffroy Saint-Hilaire (1772-1844) defended the idea of ​​the unity of the body plan of animals of various types. Lamarck's evolutionary ideas are most fully set forth in the Philosophy of Zoology (1809), although Lamarck formulated many of his evolutionary theory in introductory lectures to the course of zoology as early as 1800-1802. Lamarck believed that the steps of evolution do not lie in a straight line, as follows from the "ladder of beings" of the Swiss natural philosopher C. Bonnet, but have many branches and deviations at the level of species and genera. This performance set the stage for future family trees. Lamarck proposed the very term "biology" in its modern sense. However, the zoological works of Lamarck, the creator of the first evolutionary doctrine, contained many factual inaccuracies and speculative constructions, which is especially evident when comparing his works with the works of his contemporary, rival and critic, the creator of comparative anatomy and paleontology, Georges Cuvier (1769-1832). Lamarck believed that the driving factor of evolution could be the "exercise" or "non-exercise" of the organs, depending on the adequate direct influence of the environment. Some of the naivety of Lamarck's and Saint-Hilaire's arguments contributed greatly to the anti-evolutionary reaction to transformism. early XIX in, and caused criticism from the creationist Georges Cuvier and his school, absolutely argued from the factual side of the issue.

catastrophism and transformism

Cuvier's ideal was Linnaeus. Cuvier divided animals into four "branches", each of which is characterized by a common body plan. For these "branches", his follower A. Blainville proposed the concept of type, which fully corresponded to the "branches" of Cuvier. A phylum is not just the highest taxon in the animal kingdom. There are no and cannot be transitional forms between the four distinguished types of animals. All animals belonging to the same type are characterized by a common structural plan. This most important position of Cuvier is extremely significant even today. Although the number of types has significantly exceeded the figure 4, all biologists who speak about the type proceed from the fundamental idea that gives a lot of trouble to the propagandists of gradualism (gradualism) in evolution - the idea of ​​​​the isolation of the plans of the structure of each of the types. Cuvier fully accepted the Linnaean hierarchy of the system and built his system in the form of a branching tree. But it was not a genealogical tree, but a tree of similarity of organisms. As rightly noted by A.A. Borisyak, "having built a system on ... a comprehensive account of the similarities and differences of organisms, he thereby opened the door for the evolutionary doctrine against which he fought." Cuvier's system was apparently the first system of organic nature in which modern forms considered next to fossils. Cuvier is rightfully considered a significant figure in the development of paleontology, biostratigraphy and historical geology as sciences. Theoretical basis to highlight the boundaries between the layers was Cuvier's idea of ​​the catastrophic extinctions of fauna and flora at the boundaries of periods and epochs. He also developed the doctrine of correlations (italics by N.N. Vorontsov), thanks to which he restored the appearance of the skull as a whole, the skeleton as a whole, and, finally, gave a reconstruction appearance fossil animal. His contribution to stratigraphy, together with Cuvier, was made by his French colleague paleontologist and geologist A. Brongniard (1770-1847), and, independently of them, by the English surveyor and mining engineer William Smith (1769-1839). The term of the doctrine of the form of organisms - morphology - was introduced into the biological science of Goethe, and the doctrine itself arose at the end of the 18th century. For the creationists of that time, the concept of the unity of the structural plan meant a search for the similarity, but not the relationship, of organisms. The task of comparative anatomy was seen as an attempt to understand according to what plan the Supreme Being created all the variety of animals that we observe on Earth. Evolutionary classics call this period of development of biology "idealistic morphology". This trend was also developed by an opponent of transformism, the English anatomist and paleontologist Richard Owen (1804-1892). By the way, it was he who proposed to apply the now known analogy or homology to structures that perform similar functions, depending on whether the compared animals belong to the same structural plan, or to different ones (to the same type of animal or to different types).

Evolutionists - contemporaries of Darwin

The English arborist Patrick Matthew (1790-1874) in 1831 published a monograph "Ship timber and tree planting". The phenomenon of uneven growth of trees of the same age, the selective death of some and the survival of others have long been known to foresters. Matthew suggested that selection not only ensures the survival of the fittest trees, but can also lead to changes in species in the process. historical development. Thus, the struggle for existence and natural selection were known to him. At the same time, he believed that the acceleration of the evolutionary process depends on the will of the organism (Lamarckism). The principle of the struggle for existence coexisted with Matthew with the recognition of the existence of catastrophes: after revolutions, a few primitive forms survive; in the absence of competition after the revolution, the evolutionary process proceeds rapidly. Matthew's evolutionary ideas went unnoticed for three decades. But in 1868, after the publication of On the Origin of Species, he published his evolutionary pages. After that, Darwin got acquainted with the works of his predecessor and noted the merits of Matthew in a historical review of the 3rd edition of his work.

Charles Lyell (1797-1875) is a major figure of his time. He brought back to life the concept of actualism (“Basic Principles of Geology”, 1830-1833), which comes from ancient authors, as well as from such significant personalities in human history as Leonardo da Vinci (1452-1519), Lomonosov (1711-1765), James Hutton (England, Hutton, 1726-1797) and, finally, Lamarck. Lyell's acceptance of the concept of knowing the past through the study of the present meant the creation of the first integral theory of the evolution of the face of the Earth. English philosopher and the historian of science William Whewell (1794-1866) coined the term uniformitarianism in 1832 to refer to Lyell's theory. Lyell spoke of the invariability of the action of geological factors in time. Uniformism was the complete antithesis of Cuvier's catastrophism. “Lyell's teaching now prevails just as much,” wrote the anthropologist and evolutionist I. Ranke, “as Cuvier's teaching once dominated. At the same time, it is often forgotten that the doctrine of catastrophes could hardly have given a satisfactory schematic explanation of geological facts for so long in the eyes of the best researchers and thinkers, if it had not been based on a certain amount of positive observations. Here, too, the truth lies between the extremes of theory. As modern biologists admit, “Cuvier's catastrophism was a necessary stage in the development of historical geology and paleontology. Without catastrophism, the development of biostratigraphy would hardly have gone so fast.”

The Scotsman Robert Chambers (1802-1871), a book publisher and popularizer of science, published in London Traces of the Natural History of Creation (1844), in which he anonymously propagated the ideas of Lamarck, talked about the duration of the evolutionary process and about evolutionary development from simply organized ancestors to more complex forms . The book was designed for a wide readership and over 10 years it went through 10 editions with a circulation of at least 15 thousand copies (which in itself is impressive for that time). Controversy erupted around the book by an anonymous author. Always very restrained and cautious, Darwin stood aloof from the discussion that unfolded in England, but he carefully watched how criticism of particular inaccuracies turned into a criticism of the very idea of ​​\u200b\u200bvariability of species, so as not to repeat such errors. Chambers, after the publication of Darwin's book, immediately joined the ranks of supporters of the new doctrine.

In the 20th century, they remembered Edward Blyth (1810-1873), an English zoologist and explorer of the Australian fauna. In 1835 and 1837 he published two articles in the English Journal of Natural History in which he said that in conditions of fierce competition and a lack of resources, only the strongest had chances to leave offspring.

Thus, even before the publication of the famous work, the whole course of the development of natural science had already prepared the ground for the perception of the doctrine of the variability of species and selection.

Proceedings of Darwin

A new stage in the development of evolutionary theory came in 1859 as a result of the publication of Charles Darwin's seminal work The Origin of Species by Means of Natural Selection, or the Preservation of Favorable Races in the Struggle for Life. According to Darwin, the main driving force behind evolution is natural selection. Selection, acting on individuals, allows those organisms that are better adapted to life in a given environment to survive and leave offspring. The action of selection leads to the breakup of species into parts - daughter species, which, in turn, diverge over time to genera, families, and all larger taxa.

With his usual honesty, Darwin pointed out those who had directly pushed him to write and publish the doctrine of evolution (apparently, Darwin was not too interested in the history of science, since in the first edition of On the Origin of Species he did not mention his immediate predecessors: Wells, Matthew, Blite). Lyell and, to a lesser extent, Thomas Malthus (1766-1834) had a direct influence on Darwin in the process of creating work, with his geometric progression numbers from the demographic work "An Essay on the Law of Population" (1798). And, it can be said, Darwin was "forced" to publish his work by a young English zoologist and biogeographer Alfred Wallace (1823-1913), sending him a manuscript in which, independently of Darwin, he sets out the ideas of the theory of natural selection. At the same time, Wallace knew that Darwin was working on evolutionary doctrine, for the latter himself wrote to him about this in a letter dated May 1, 1857: “This summer it will be 20 years (!) Since I started my first notebook on the question of how and in what way species and varieties differ from each other. Now I am preparing my work for publication... but I do not intend to publish it earlier than in two years... Indeed, it is impossible (in the framework of a letter) to state my views on the causes and methods of changes in the state of nature; but step by step I came to a clear and distinct idea - true or false, this must be judged by others; because, alas! - the most unshakable confidence of the author of the theory that he is right is in no way a guarantee of its truth! Darwin's sanity can be seen here, as well as the gentlemanly attitude of the two scientists towards each other, which is clearly seen when analyzing the correspondence between them. Darwin, having received the article on June 18, 1858, wanted to submit it to the press, keeping silent about his work, and only at the insistence of his friends wrote a “brief extract” from his work and presented these two works to the judgment of the Linnean Society.

Darwin fully accepted the idea of ​​gradual development from Lyell and, one might say, was a uniformitarian. The question may arise: if everything was known before Darwin, then what is his merit, why did his work cause such a resonance? But Darwin did what his predecessors failed to do. First, he gave his work a very topical title that was "on everyone's lips." The public had a burning interest precisely in "The Origin of Species by Means of Natural Selection, or the Preservation of Favored Races in the Struggle for Life." It is difficult to recall another book in the history of world natural science, the title of which would equally clearly reflect its essence. Perhaps Darwin had seen the title pages or the titles of his predecessors' works, but simply had no desire to get acquainted with them. We can only guess how the public would have reacted if Matthew had thought to release his evolutionary views under the title "The possibility of plant species changing over time through survival (selection) of the fittest." But, as we know, "The ship's construction timber ..." did not attract attention.

Secondly, and most importantly, Darwin was able to explain to his contemporaries the reasons for the variability of species on the basis of his observations. He rejected as untenable the notion of "exercise" or "non-exercise" of organs and turned to the facts of breeding new breeds of animals and plant varieties by people - to artificial selection. He showed that the indefinite variability of organisms (mutations) is inherited and can become the beginning of a new breed or variety, if it is useful to man. Transferring these data to wild species, Darwin noted that only those changes that are beneficial to the species for successful competition with others can be preserved in nature, and spoke of the struggle for existence and natural selection, to which he attributed an important, but not the only role of the driving force of evolution. Darwin not only gave theoretical calculations of natural selection, but also showed on the basis of actual material the evolution of species in space, with geographic isolation (finches) and, from the standpoint of strict logic, explained the mechanisms of divergent evolution. He also introduced the public to the fossil forms of giant sloths and armadillos, which could be seen as evolution over time. Darwin also allowed for the possibility of long-term preservation of a certain average species norm in the process of evolution by eliminating any deviant variants (for example, sparrows that survived after a storm had an average wing length), which was later called stasigenesis. Darwin was able to prove to everyone the reality of the variability of species in nature, therefore, thanks to his work, the idea of ​​\u200b\u200bthe strict constancy of species came to naught. It was pointless for the statics and fixists to continue to persist in their positions.

Development of Darwin's ideas

As a true follower of gradualism, Darwin was concerned that the absence of transitional forms could be the collapse of his theory, and attributed this lack to the incompleteness of the geological record. Darwin was also worried about the idea of ​​"dissolving" a newly acquired trait in a number of generations, with subsequent crossing with ordinary, unaltered individuals. He wrote that this objection, along with breaks in the geological record, is one of the most serious for his theory.

Darwin and his contemporaries did not know that in 1865 the Austro-Czech naturalist abbot Gregor Mendel (1822-1884) discovered the laws of heredity, according to which the hereditary trait does not “dissolve” in a number of generations, but passes (in case of recessiveness) into a heterozygous state and can be propagated in a population environment.

In support of Darwin, scientists such as the American botanist Aza Gray (1810-1888) began to come out; Alfred Wallace, Thomas Henry Huxley (Huxley; 1825-1895) - in England; the classic of comparative anatomy Karl Gegenbaur (1826-1903), Ernst Haeckel (1834-1919), zoologist Fritz Müller (1821-1897) - in Germany. No less distinguished scientists criticize Darwin's ideas: Darwin's teacher, professor of geology Adam Sedgwick (1785-1873), the famous paleontologist Richard Owen, a major zoologist, paleontologist and geologist Louis Agassiz (1807-1873), German professor Heinrich Georg Bronn (1800-1873). 1862).

An interesting fact is that Darwin's book on German it was Bronn who translated, who did not share his views, but who believes that the new idea has the right to exist (the modern evolutionist and popularizer N.N. Vorontsov pays tribute to Bronn in this as a true scientist). Considering the views of another opponent of Darwin - Agassiz, we note that this scientist spoke about the importance of combining the methods of embryology, anatomy and paleontology to determine the position of a species or other taxon in the classification scheme. In this way, the species gets its place in the natural order of the universe. It was curious to know that Haeckel, an ardent supporter of Darwin, widely promotes the triad postulated by Agassiz, the “method of triple parallelism” already applied to the idea of ​​kinship, and it, warmed up by Haeckel’s personal enthusiasm, captures contemporaries. All zoologists, anatomists, embryologists, and paleontologists who are anything like serious begin to build entire forests of phylogenetic trees. With the light hand of Haeckel, it spreads as the only possible idea of ​​monophyly - origin from one ancestor, which reigned supreme over the minds of scientists in the middle of the 20th century. Modern evolutionists, based on the study of the method of reproduction of the Rhodophycea algae, which is different from all other eukaryotes (fixed and male and female gametes, the absence of a cell center and any flagellar formations), speak of at least two independently formed ancestors of plants. At the same time, they found out that “The emergence of the mitotic apparatus occurred independently at least twice: in the ancestors of the kingdoms of fungi and animals, on the one hand, and in the sub-kingdoms of true algae (except for Rhodophycea) and higher plants, on the other” (exact quote, p. 319) . Thus, the origin of life is recognized not from one proto-organism, but at least from three. In any case, it is noted that already “no other scheme, like the proposed one, can turn out to be monophyletic” (ibid.). The theory of symbiogenesis, which explains the appearance of lichens (combination of algae and fungus) also led scientists to polyphyly (origin from several unrelated organisms) (p. 318). And this is the most important achievement of the theory. Besides, latest research they say they find everything more examples, showing "the prevalence of paraphilia and in the origin of relatively closely related taxa." For example, in the “subfamily of African tree mice Dendromurinae: the genus Deomys is molecularly close to the true Murinae mice, and the genus Steatomys is close in DNA structure to the giant mice of the subfamily Cricetomyinae. At the same time, the morphological similarity of Deomys and Steatomys is undoubted, which indicates the paraphyletic origin of Dendromurinae. Therefore, the phylogenetic classification needs to be revised, already on the basis of not only external similarity, but also the structure genetic material(p. 376). The experimental biologist and theorist August Weismann (1834-1914) spoke in a fairly clear form about the cell nucleus as the carrier of heredity. Regardless of Mendel, he came to the most important conclusion about the discreteness of hereditary units. Mendel was so ahead of his time that his work remained virtually unknown for 35 years. Weismann's ideas (sometime after 1863) became the property of a wide range of biologists, a subject for discussion. The most fascinating pages of the origin of the doctrine of chromosomes, the emergence of cytogenetics, the creation of T.G. Morgan chromosome theory heredity in 1912-1916. – all this was strongly stimulated by August Weismann. Exploring embryonic development sea ​​urchins, he proposed to distinguish between two forms of cell division - equatorial and reduction, i.e. approached the discovery of meiosis - milestone combinative variability and the sexual process. But Weisman could not avoid some speculation in his ideas about the mechanism of heredity transmission. He thought that the entire set of discrete factors - "determinants" - have only cells of the so-called. "germ line". Some determinants get into some of the cells of the "soma" (body), others - others. Differences in the sets of determinants explain the specialization of soma cells. So, we see that, having correctly predicted the existence of meiosis, Weismann was mistaken in predicting the fate of the distribution of genes. He also extended the principle of selection to competition between cells, and since cells are carriers of certain determinants, he spoke of their struggle with each other. The most modern concepts of "selfish DNA", "selfish gene", developed at the turn of the 70s and 80s. 20th century in many respects have something in common with the Weismann competition of determinants. Weisman emphasized that the "germ plasm" is isolated from the cells of the soma of the whole organism, and therefore spoke of the impossibility of inheriting the characteristics acquired by the body (soma) under the influence of the environment. But many Darwinists accepted this idea of ​​Lamarck. Weisman's harsh criticism of this concept caused a negative attitude towards him and his theory, and then to the study of chromosomes in general, from orthodox Darwinists (those who recognized selection as the only factor in evolution).

The rediscovery of Mendel's laws occurred in 1900 in three different countries: Holland (Hugo de Vries 1848-1935), Germany (Karl Erich Korrens 1864-1933) and Austria (Erich von Tschermak 1871-1962), who simultaneously discovered the forgotten work of Mendel. In 1902, Walter Sutton (Seton, 1876-1916) gave a cytological justification for Mendelism: diploid and haploid sets, homologous chromosomes, the conjugation process during meiosis, the prediction of the linkage of genes located on the same chromosome, the concept of dominance and recessiveness, as well as allelic genes - all this was demonstrated on cytological preparations, based on the exact calculations of Mendeleev's algebra, and very different from hypothetical family trees, from the style of naturalistic Darwinism of the 19th century. The mutational theory of de Vries (1901-1903) was not accepted not only by the conservatism of orthodox Darwinists, but also by the fact that on other plant species, researchers were unable to obtain the wide range of variability achieved by him on Oenothera lamarkiana (it is now known that evening primrose is a polymorphic species , which has chromosomal translocations, some of which are heterozygous, while homozygotes are lethal.De Vries chose a very successful object for obtaining mutations and at the same time not entirely successful, since in his case it was necessary to extend the results achieved to other plant species). De Vries and his Russian predecessor, the botanist Sergei Ivanovich Korzhinsky (1861-1900), who wrote in 1899 (Petersburg) about sudden spasmodic "heterogeneous" deviations, thought that the possibility of the manifestation of macromutations rejected Darwin's theory. At the dawn of the formation of genetics, many concepts were expressed, according to which evolution did not depend on the external environment. The Dutch botanist Jan Paulus Lotsi (1867-1931), who wrote the book Evolution by Hybridization, also came under criticism from the Darwinists, where he rightly drew attention to the role of hybridization in plant speciation.

If in mid-eighteenth century, it seemed an insurmountable contradiction between transformism (continuous change) and the discreteness of taxonomic units of systematics, then in the 19th century it was thought that gradualistic trees built on the basis of kinship came into conflict with the discreteness of hereditary material. Evolution by visually distinguishable large mutations could not be accepted by the gradualism of the Darwinists.

Trust in mutations and their role in shaping the variability of a species was restored by Thomas Gent Morgan (1886-1945) when this American embryologist and zoologist turned to genetic research in 1910 and eventually settled on the famous Drosophila. Probably, one should not be surprised that 20-30 years after the events described, it was population geneticists who came to evolution not through macromutations (which began to be recognized as unlikely), but through a steady and gradual change in the frequencies of allelic genes in populations. Since macroevolution by that time seemed to be an indisputable continuation of the studied phenomena of microevolution, gradualness began to seem an inseparable feature of the evolutionary process. There was a return to Leibniz's "law of continuity" at a new level, and in the first half of the 20th century a synthesis of evolution and genetics could take place. Once again, once-opposite concepts have united. (names, conclusions of evolutionists and chronology of events are taken from Nikolay Nikolaevich Vorontsov, "Development of evolutionary ideas in biology, 1999)

Recall that in the light of the latest biological ideas put forward from the positions of materialism, now again there is a distance from the law of continuity, now not genetics, but the evolutionists themselves. The famous S.J. Gould raised the issue of punctualism (punctuated equilibrium), as opposed to generally accepted gradualism, in order to explain the reasons for the already obvious picture of the absence of transitional forms among fossils, i.e. the impossibility of building a truly continuous line of kinship from the origins to the present. There is always a break in the geological record.

Modern theories of biological evolution

Synthetic theory of evolution

The synthetic theory in its current form was formed as a result of rethinking a number of provisions of classical Darwinism from the standpoint of genetics at the beginning of the 20th century. After the rediscovery of Mendel's laws (in 1901), the evidence of the discrete nature of heredity, and especially after the creation of theoretical population genetics by the works of R. Fisher (-), J. B. S. Haldane, Jr. (), S. Wright ( ; ), the teaching Darwin acquired a solid genetic foundation.

Neutral theory of molecular evolution

The theory of neutral evolution does not dispute the decisive role of natural selection in the development of life on Earth. The discussion is about the proportion of mutations that have an adaptive value. Most biologists accept a number of results of the theory of neutral evolution, although they do not share some of the strong statements originally made by M. Kimura.

Epigenetic theory of evolution

The main provisions of the epigenetic theory of evolution were formulated in the th year by M. A. Shishkin on the basis of the ideas of I. I. Schmalhausen and K. H. Waddington. As the main substrate of natural selection, the theory considers a holistic phenotype, and selection not only fixes beneficial changes, but also takes part in their creation. The fundamental influence on heredity is exerted not by the genome, but by the epigenetic system (ES) - a set of factors affecting ontogenesis. From ancestors to descendants, the general organization of ES is transmitted, which forms the organism in the course of its individual development, and selection leads to the stabilization of a number of successive ontogenies, eliminating deviations from the norm (morphoses) and forming a stable development trajectory (creod). Evolution, according to ETE, consists in the transformation of one creod into another under the perturbing influence of the environment. In response to the perturbation, the ES destabilizes, as a result of which the development of organisms along deviating paths of development becomes possible, and multiple morphoses arise. Some of these morphoses receive a selective advantage, and over the course of subsequent generations, their ES develops a new stable development trajectory, a new creod is formed.

Ecosystem theory of evolution

This term is understood as a system of ideas and approaches to the study of evolution, focusing on the features and patterns of evolution of ecosystems at various levels - biocenoses, biomes and the biosphere as a whole, and not taxa (species, families, classes, etc.). The provisions of the ecosystem theory of evolution are based on two postulates:

• Naturalness and discreteness of ecosystems. An ecosystem is a real-life (and not isolated for the convenience of the researcher) object, which is a system of interacting biological and non-biological (eg soil, water) objects territorially and functionally delimited from other similar objects. The boundaries between ecosystems are clear enough to speak about the independent evolution of neighboring objects.
• The decisive role of ecosystem interactions in determining the rate and direction of population evolution. Evolution is seen as a process of creating and filling ecological niches or licenses.

The ecosystem theory of evolution operates with such terms as coherent and incoherent evolution, ecosystem crises of various levels. The modern ecosystem theory of evolution is based mainly on the works of Soviet and Russian evolutionists: V. A. Krasilov, S. M. Razumovsky, A. G. Ponomarenko, V. V. Zherikhin and others.

Evolutionary doctrine and religion

Although many unclear questions about the mechanisms of evolution remain in modern biology, the vast majority of biologists do not doubt the existence of biological evolution as a phenomenon. However, some believers of a number of religions find some provisions of evolutionary biology contrary to their religious beliefs, in particular, the dogma of the creation of the world by God. In this regard, in a part of society, almost from the moment of the birth of evolutionary biology, there has been a certain opposition to this teaching from the religious side (see creationism), which at some times and in some countries has reached criminal sanctions for teaching evolutionary doctrine (which caused, for example, the scandalous well-known "monkey process" in the USA in g.).

It should be noted that the accusations of atheism and the denial of religion, cited by some opponents of evolutionary doctrine, are based to a certain extent on a misunderstanding of the nature of scientific knowledge: in science, no theory, including the theory of biological evolution, can either confirm or deny the existence of such otherworldly subjects, like God (if only because God, when creating living nature, could use evolution, as the theological doctrine of "theistic evolution" claims).

On the other hand, the theory of evolution, being a scientific theory, considers the biological world as part of the material world and relies on its natural and self-sufficient, that is, its natural origin, which is therefore alien to any otherworldly or divine intervention; alien for the reason that the growth of scientific knowledge, penetrating into the previously incomprehensible and explainable only by the activity of otherworldly forces, somehow beats the soil from religion (when explaining the essence of the phenomenon, the need for a religious explanation disappears, because there is a convincing natural explanation). In this regard, evolutionary teaching can be aimed at denying the existence of extranatural forces, or rather their interference in the process of development of the living world, which one way or another suggests religious systems.

Efforts to oppose evolutionary biology to religious anthropology are also mistaken. From the point of view of the methodology of science, the popular thesis "man descended from apes" is only an oversimplification (see reductionism) of one of the conclusions of evolutionary biology (about the place of man as a biological species on the phylogenetic tree of living nature), if only because the concept of “man” is ambiguous: man as a subject of physical anthropology is by no means identical to man as a subject of philosophical anthropology, and it is incorrect to reduce philosophical anthropology to physical one.

Many believers of different religions do not find evolutionary teachings contrary to their faith. The theory of biological evolution (along with many other sciences - from astrophysics to geology and radiochemistry) contradicts only the literal reading of the sacred texts that tell about the creation of the world, and for some believers this is the reason for the rejection of almost all conclusions natural sciences who study the past of the material world (literalist creationism).

Among believers who profess the doctrine of literal creationism, there are a number of scientists who are trying to find scientific evidence for their doctrine (the so-called "scientific creationism"). However, the scientific community disputes the validity of this evidence.

Literature

• Berg L.S. Nomogenesis, or Evolution based on regularities. - Petersburg: State Publishing House, 1922. - 306 p.
• Kordyum V. A. Evolution and the biosphere. - K.: Naukova Dumka, 1982. - 264 p.
• Krasilov V. A. Unsolved problems of the theory of evolution. - Vladivostok: DVNTs AN SSSR, 1986. - S. 140.
• Lima de Faria A. Evolution without selection: Autoevolution of form and function: Per. from English. - M.: Mir, 1991. - S. 455.
• Nazarov V.I. Evolution not according to Darwin: Changing the evolutionary model. Tutorial. Ed. 2nd, corrected .. - M .: Publishing house LKI, 2007. - 520 p.
• Tchaikovsky Yu.V. The science of life development. Experience of the theory of evolution. - M.: Association of scientific publications KMK, 2006. - 712 p.
• Golubovsky M. D. Non-canonical legacy changes // Nature. - 2001. - No. 8. - S. 3–9.
• Meyen S.V. The path to a new synthesis, or where they lead homologous series? // Knowledge is power. - 1972. - № 8.

In 1859, the English naturalist Charles Darwin published The Origin of Species. Since then, evolutionary theory has been key in explaining the laws of development. organic world. It is taught in schools in biology classes, and even some churches have recognized its validity.

What is Darwin's theory?

Darwin's theory of evolution is the concept that all organisms descend from a common ancestor. It emphasizes the naturalistic origin of life with change. Complex creatures evolve from simpler ones, it takes time. Random mutations occur in the genetic code of an organism, useful ones are preserved, helping to survive. Over time, they accumulate, and the result is a different kind, not just a variation of the original, but a completely new creature.

The main provisions of Darwin's theory

Darwin's theory of the origin of man is included in the general theory of the evolutionary development of living nature. Darwin believed that Homo Sapiens descended from an inferior life form and shared a common ancestor with the ape. The same laws led to its appearance, thanks to which other organisms appeared. The evolutionary concept is based on the following principles:

1. Overproduction. Species populations remain stable because a small proportion of the offspring survive and reproduce.
2. Fight for survival. Children of every generation must compete to survive.
3. fixture. Adaptation is an inherited trait that increases the likelihood of surviving and reproducing in a particular environment.
4. Natural selection. The environment "chooses" living organisms with more suitable traits. The offspring inherit the best, and the species is improved for a particular habitat.
5. Speciation. Over generations, beneficial mutations gradually increase, while the bad ones disappear. Over time, the accumulated changes become so great that the result is a new species.

Darwin's theory - fact or fiction?

Darwin's theory of evolution has been the subject of much debate for centuries. On the one hand, scientists can tell what ancient whales were like, but on the other hand, they lack fossil evidence. Creationists (adherents of the divine origin of the world) take this as proof that evolution did not happen. They scoff at the idea that a land whale ever existed.

Ambulocetus

Evidence for Darwin's theory

To the delight of Darwinists, in 1994, paleontologists found the fossil of Ambulocetus, a walking whale. Webbed front paws helped him move on land, and powerful hind legs and tail helped him swim deftly. IN last years find more and more remains of transitional species, the so-called "missing links". So, Charles Darwin's theory of the origin of man was supported by the discovery of the remains of Pithecanthropus, an intermediate species between ape and man. In addition to paleontological evidence, there is other evidence for evolutionary theory:

1. Morphological- according to Darwin's theory, each new organism is not created by nature from scratch, everything comes from a common ancestor. For example, the similar structure of the paws of a mole and the wings of a bat is not explained in terms of utility, they probably received it from a common ancestor. This also includes five-fingered limbs, a similar oral structure in different insects, atavisms, rudiments (organs that have lost their importance in the process of evolution).
2. Embryological- in all vertebrates there is a huge similarity of embryos. A human baby that has been in the womb for one month has gill sacs. This indicates that the ancestors were aquatic inhabitants.
3. Molecular genetic and biochemical- the unity of life at the level of biochemistry. If all organisms did not come from one ancestor, they would have their own genetic code, but the DNA of all creatures consists of 4 nucleotides, and there are over 100 of them in nature.

Refutation of Darwin's theory

Darwin's theory is unprovable - this moment alone is enough for critics to question its entire validity. No one has ever observed macroevolution—no one has seen how one species evolved into another. And in general, when at least one monkey will already turn into a man? This question is asked by all those who doubt the validity of Darwin's arguments.

Facts that refute Darwin's theory:

1. Studies have shown that the planet Earth is approximately 20-30 thousand years old. This has recently been discussed by many geologists studying the quantity space dust on our planet, the age of rivers and mountains. Evolution, according to Darwin, took billions of years.
2. Humans have 46 chromosomes, while apes have 48. This does not fit in with the idea that humans and apes had a common ancestor. Having “lost” the chromosomes along the way from the monkey, the species could not evolve into a reasonable one. Over the past few thousand years, not one whale has come to land, and not one monkey has turned into a man.
3. Natural beauty, to which, for example, anti-Darwinists attribute the peacock's tail, has nothing to do with utility. If there was evolution, the world would be inhabited by monsters.

Darwin's theory and modern science

Darwin's evolutionary theory saw the light when scientists still knew nothing about genes. Darwin observed the pattern of evolution, but did not know about the mechanism. At the beginning of the 20th century, genetics began to develop - chromosomes and genes were discovered, and later the DNA molecule was deciphered. For some scientists, Darwin's theory was refuted - the structure of organisms turned out to be more complex, and the number of chromosomes in humans and monkeys was different.

But supporters of Darwinism say that Darwin never said that man descended from apes - they have a common ancestor. The discovery of genes for Darwinists gave impetus to the development of the synthetic theory of evolution (the inclusion of genetics in Darwin's theory). The physical and behavioral changes that make natural selection possible occur at the level of DNA and genes. Such changes are called mutations. Mutations are the raw material on which evolution operates.

Darwin's theory - interesting facts

The theory of evolution of Charles Darwin is the work of a man who, having abandoned the profession of a doctor because of, went to study theology. A few more interesting facts:

1. The phrase "survival of the fittest" belongs to a contemporary and like-minded Darwin - Herbert Spencer.
2. Charles Darwin not only studied exotic animals, but also dined on them.
3. The Anglican Church officially apologized to the author of the theory of evolution, though 126 years after his death.

Darwin's theory and Christianity

At first glance, the essence of Darwin's theory contradicts the divine universe. At one time, the religious environment was hostile to new ideas. Darwin himself ceased to be a believer in the course of his work. But now many representatives of Christianity have come to the conclusion that there can be real reconciliation - there are those who have religious beliefs and do not deny evolution. The Catholic and Anglican churches accepted Darwin's theory, explaining that God, as the creator, gave the impetus to the beginning of life, and after that it developed naturally. The Orthodox wing is still unfriendly to Darwinists.

From a modern point of view, the main evidence for the evolution of the world of living organisms are:

unity of living nature, i.e. uniform principles cellular structure, functioning, heredity and variability of all living organisms, regardless of the stage of their development;

the existence of fossils transitional organisms, combining the features of older and younger groups (indicates the historical connection of different groups of organisms; an example is the first bird Archeopteryx) ',

the existence of phylogenetic(or paleontological) rows, i.e. rows of fossil forms connected with each other in the process of evolution and reflecting its course;

homologous organs, i.e. bodies having general structure and origin, but performing different functions (allows you to establish the degree of relationship between organisms and trace their evolution);

existence in organisms of different groups similar bodies, i.e. organs that have an external resemblance and perform the same functions, but have a different origin (indicates similar directions evolution of different groups of organisms under the influence of natural selection);

some organisms have vestiges- organs that are laid down during embryonic development, but then cease to develop and remain in adult forms in an underdeveloped state;

appearance in certain organisms of this species atavisms- signs that existed in distant ancestors, but were lost in the course of evolution;

similarity of embryonic development of vertebrates (All multicellular animals develop from one fertilized egg and go through the stages of crushing, blastula, gastrula, the formation of a three-layer embryo and the formation of organs from germ layers, which indicates the unity of their origin).

biogenetic law(F. Müller, E. Haeckel): each individual in individual development(ontogenesis) repeats the history of the development of its species (phylogenesis), i.e. ontogeny is a brief repetition of phylogeny.

The main provisions of the synthetic theory of evolution

Synthetic theory of evolution(modern Darwinism) - the doctrine of the evolution of the organic world, developed on the basis of data modern genetics, ecology and classical Darwinism.

❖ The main provisions of the synthetic theory of evolution:
■ elemental material for evolution, mutations and their combinations are provided that create heritable geno- and phenotypic diversity within the species;
■ main driving factor evolution - natural selection as a consequence of the struggle for existence;
■ smallest (elementary) unit evolution - population;
■ each population evolves regardless from populations of the same species;
■ Generally, evolution is divergent , i.e. one taxon can become the ancestor of several taxa;
■ evolution wears gradual and prolonged and passes as a successive change of one temporary population by a succession of subsequent temporary populations;
■ evolution has non-directional character (i.e. does not have a specific end goal);
■ macroevolution for more high level than a species goes through microevolution; while macroevolution obeys the same patterns , which is microevolution.

Levels of evolutionary transformations:
■ microevolution,
■ macroevolution.

microevolution- a set of evolutionary processes occurring in populations and leading to changes in their gene pool and the subsequent formation of new species.
■ Microevolution is the basis of the historical development of the organic world.
■Microevolutionary changes are a necessary prerequisite for speciation, but they may not go beyond the scope of a given species.

macroevolution is a set of processes of evolutionary transformation at the supraspecies level , leading to the emergence of systematic groups of a higher order than the species - genera, families, orders, classes, types, etc.
■ Macroevolution is carried out according to the general patterns characteristic of speciation. There are no fundamental differences between macroevolution and microevolution.

Population as an elementary unit of evolution

An individual cannot be a unit of evolution, since its genotype is determined at the moment of fertilization and it is mortal. The contribution of an individual to evolution is determined by its hereditary variability and the transmission of genes to descendants. Evolution takes place only populations - a group of individuals that are available to each other, can interbreed with each other and give viable offspring.

population is a collection of individuals of the same species that exist for a long time in a certain territory and are relatively isolated from other individuals of the same species.
■ A population is a form of existence of a species in specific environmental conditions.
■ Population - the smallest part of the species, which is elementary unit of evolution .

♦The main characteristics of the population: abundance, density, sex and age composition, genetic polymorphism.

❖ Population properties:
■ in one population individuals are as similar as possible (this is due to the high probability of interbreeding of individuals within the population and the same selection pressure);
■ in populations goes struggle for existence and operates natural selection (due to this, only individuals with changes that are useful under given conditions survive and leave offspring);
■ populations of the same species genetically heterogeneous (due to continuously emerging hereditary variability);
■ population full of mutations and have ample opportunities to improve existing and develop new adaptations when the environment changes;
■ population different from each other frequency of manifestation one or the other signs (because in different conditions, different signs are subjected to natural selection);
■ in range zones where border different populations of the same species gene exchange between them (this ensures the genetic unity of the species and contributes to its greater variability and better adaptability to habitat conditions);
■ different populations of the same species are in relative genetic isolation from each other;
■ as a result, each population evolves independently from other populations of the same species;
■ the population is a continuous stream of generations and potentially immortal .

gene pool- a set of genotypes of all individuals of a population, species.

❖ Hardy-Weinberg law (1908): in large populations with free crossing of individuals and in the absence of mutations, selection and mixing with other populations, an equilibrium is established, characterized by time-constant frequencies of occurrence of genes, homo- and heterozygotes, and

p 2 + 2 pq + q 2 = l; p + q = 1,

where p is the frequency of occurrence of the dominant gene, p 2 is the frequency of occurrence of dominant homozygotes, q is the frequency of occurrence of the recessive gene, q 2 is the frequency of occurrence of recessive homozygotes, 2 pq is the frequency of occurrence of heterozygotes.

■ Such genotypic balance is possible only in populations with large numbers individuals and is due to free crossing between them.

Elementary evolutionary phenomenon- a long-term and directed change in the gene pool of a population.

■ Under conditions of persistent environmental change in a certain direction, natural selection from generation to generation will preserve adapted phenotypes, and therefore, directionally rearrange genotypes, thereby leading to a change in the gene pool of the population.

Elementary Factors (preconditions) of evolution

Elementary Factors(or background) evolution - factors leading to genetic variability in the structure of a population (i.e., to a violation of the Hardy-Weinberg law): mutation process, combinative variability, gene flow, population waves, gene drift, natural selection(random factors) and various forms isolation (limiting the free crossing of organisms).

mutation process in the population due to the action of mutagenic environmental factors. It goes constantly and is random and non-directional. In some species gene mutations carry from 10 to 25% of individuals. Most of the mutations reduce the viability of individuals or are neutral. However, upon transition to a heterozygous state, mutations can increase the viability of offspring (the phenomenon of heterosis during inbreeding is observed). Dominant mutations immediately fall under the influence of natural selection. Recessive mutations appear phenotypically and fall under the influence of natural selection only after a few generations. permanent the occurrence of mutations and new combinations of genes when crossing inevitably causes hereditary changes in the population.

Combination variability enhances the influence of the mutation process. As experience shows, the viability of mutations depends on what genes surround them. Having arisen, individual mutations are in the vicinity of certain genes and other mutations. Depending on its environment, the same mutation can play both a positive and a negative role in evolution.

Flow (or migration) of genes- the exchange of genes between different populations of the same species as a result of free crossing of their individuals, which occurs during seasonal movements of animals during breeding periods and as a result of the resettlement of young animals.

Meaning of gene flow:

■ it increases the genotypic variability of a population;
■ in its influence on the gene pool of a population often exceeds the efficiency of the mutation process;
■ the movement of a small group of individuals outside the maternal population can lead to the emergence of a new isolated population, characterized by significant genotypic uniformity ( founder effect ).

population waves(or " waves of life”) are periodic changes (fluctuations) in the number of individuals in a population associated with periodic changes in the intensity of environmental factors (change of seasons, abundance or lack of food, droughts, frosts, etc.).

Importance of population waves:
■ an increase in the number of individuals entails a proportional increase in the probability of mutations;
■ a decrease in the number of individuals leads to a change in the gene pool of the population (due to the loss of some gene alleles as a result of the death of individuals) — drift of genes.

Gene drift- the process of random non-directional change in allele frequencies in a population with a small population.

■ The consequences of genetic drift are unpredictable: it can either lead to the death of a small population or make it even more adapted to a given environment.

Meaning of Genetic Drift:

■ the proportion of hereditary variability in a population decreases and its genetic homogeneity increases (as a result, different populations living in similar conditions may lose their original similarity);

■ in spite of natural selection, a mutant gene may persist in a population that reduces the viability of individuals.

Forms of natural selection

Natural selection- this is a process of preferential survival and subsequent reproduction of individuals with hereditary changes in traits that are useful in given environmental conditions, the consequence of which is the improvement of adaptation and speciation (modern definition).

❖ The main forms of natural selection: moving, stabilizing, disruptive.

Moving(or directed) selection - selection in favor of individuals with useful deviations from the average value of the trait previously established in the population.

■ Individuals in a population are heterogeneous in phenotype, genotype and reaction rate (variation curve). With a long-term gradual change in environmental conditions in a certain direction, individuals with trait deviations from the average value in this direction get an advantage. The variation curve shifts or expands in the direction of adaptation to new conditions of existence. New intraspecific forms appear in the population.

Stabilizing selection- selection in favor of individuals with an average value of a trait that has been established in the population.

■ Due to the mutation process and combinative variability, individuals with traits that deviate from the average always appear in the population. In the absence of changes in environmental conditions, such individuals are eliminated. As a result, the relative stability of the organization of the species and its genetic structure is developed.

disruptive(or tearing) selection- selection directed against the average, previously established in the population, of the value of the trait and favoring individuals of two or more phenotypes that deviated from the intermediate form.

It operates under greatly changed environmental conditions, when the bulk of individuals lose their adaptability to them, and individuals with extreme values ​​of the trait acquire advantages. As a result, the population is torn according to this trait into several groups living in the same territory, which leads to its polymorphism .

Polymorphism - the existence of several forms according to a certain trait in one population.

Additional forms of natural selection:

■ balancing selection maintains and regulates genetic variability in a population without the emergence of new forms (example: two forms of two-point ladybug: red tolerates wintering better and prevails in spring, black breeds more intensively in summer and prevails in autumn); expands the adaptive capabilities of the population;

■destabilizing selection: the advantage is received by the population in which the individuals are the most diverse in any trait that significantly increases the variability of the population.

In nature, a certain form of selection rarely occurs in a "pure form". Usually, speciation begins with the predominance of one form of selection, and then another form takes on the leading role.

Adaptations (devices)

Adaptation (or adaptation) is a complex of morphological, physiological, behavioral and other features of an individual, population or species that ensures success in competition with other individuals, populations or species and resistance to environmental factors. Adaptation is the result of the factors of evolution.

Relative nature of adaptations: corresponding to a specific habitat, adaptations lose their significance when it changes (the mountain hare during a delay in winter or during a thaw, in early spring it is noticeable against the background of arable land and trees; aquatic plants die when water bodies dry up, etc.).

The idea of ​​the development of living nature - the idea of ​​evolution - can be traced in the works of the ancient materialists of India, China, Mesopotamia, Egypt, Greece. As early as the beginning of the 1st millennium BC. e. in India, there were philosophical schools that defended the ideas of the development of the material world (including the organic one) from the "forematter". In even more ancient texts of Ayur-Vedas, it is stated that man descended from monkeys who lived about 18 million years ago (when translated into modern reckoning on the mainland, which united Hindustan and Southeast Asia. Approximately 4 million years ago, the ancestors of modern people, allegedly switched to collective food production, which gave them the opportunity to stock up.Modern man, according to these ideas, appeared a little less than 1 million years ago.Of course, these were only brilliant guesses based on an excellent knowledge of human and animal anatomy.

In China, 2 thousand years BC. e. selection of cattle, horses and ornamental plants was carried out. At the end of the 1st millennium BC. e. there was a classification of plants (drupaceous, leguminous, succulent, creeping, shrubs, etc.). At the same time, teachings were spread in China about the possibility of transforming some living beings into others in the process of evolution. Close ties between countries ancient world made this knowledge the property of the philosophers of the Mediterranean countries, where they were further developed. Aristotle (4th century BC) already has a coherent system of views on the development of living nature, based on an analysis of the general plan of the structure of higher animals, homology and correlation of organs. The fundamental works of Aristotle "On the Parts of Animals", "History of Animals", "On the Origin of Animals" had a great influence on the subsequent development of biology.

However, despite the outward closeness of the ancient and our ideas, the views of the ancient thinkers were in the nature of abstract speculative doctrines.

The decline of knowledge in the Middle Ages.

After almost two thousand years of development of knowledge in the Ancient World - China, India, Egypt, Greece - in Europe for many centuries comes the dark Middle Ages, "a dark night for natural science." People were burned at the stake not only for expressing the idea of ​​the development of nature, but also for reading the books of ancient naturalists and philosophers. The forcible introduction of faith into science turns the latter into an appendage of religion.

About 6 thousand years were allotted for the entire development of the world by church teaching, for centuries it has been preserved as an official point of view on the creation of the world by the Lord God for 4004 BC. e. The study of nature was effectively forbidden; hundreds of talented scientists, thousands and thousands of ancient books were destroyed during this time. In Spain alone, about 35 thousand people were burned at the stakes of the Inquisition and more than 300 thousand were tortured. The last official bonfire of the Inquisition burned in 1826. Of course, during these years, the accumulation of natural science knowledge (in monasteries and universities) continued.

Spread of the ideas of evolutionism in the Renaissance and Enlightenment.

The Middle Ages are replaced by the Renaissance (XV-XVI centuries). With its onset, the works of ancient naturalists are again becoming widespread. The books of Aristotle and other ancient authors come to European countries from North Africa and Spain in translation from Arabic. As a result of the development of trade and navigation, knowledge about the diversity of the organic world is rapidly growing, and an inventory of flora and fauna is taking place. In the XVI century. the first multi-volume descriptions of the animal and plant world appear, anatomy achieves brilliant successes, in the 17th century. W. Harvey created the doctrine of blood circulation, and R. Hooke, M. Malpighi and others laid the foundations for microscopy and the study of the cellular structure of organisms. Growing natural science knowledge needed to be systematized and generalized. The first stage of the process of systematization of biological knowledge ends in the 18th century. the works of the great Swedish naturalist K. Linnaeus (1707-1778).

The ideas of evolution are beginning to be traced more and more clearly in the works of naturalists and philosophers. Even G. Leibniz (1646-1716) proclaimed the principle of gradation of living beings and predicted the existence of transitional forms between plants and animals. The principle of gradation was further developed in the concept of the "ladder of beings", which for some became an expression of ideal continuity in the structure, and for others - proof of the transformation, evolution of living nature. In 1749, the multi-volume "Natural History" by J. Buffon begins to appear, in which he substantiates the hypothesis about the past development of the Earth. In his opinion, it covers 80-90 thousand years, but only in recent periods do living organisms appear on Earth from inorganic substances: first plants, then animals and humans. J. Buffon saw evidence of the unity of origin in terms of the structure of animals and explained the similarity of close forms by their origin from common ancestors.

The idea of ​​evolution is also embedded in the works of the encyclopedist D. Diderot (1713-1784): small changes in all creatures and the duration of the existence of the Earth can explain the emergence of the diversity of the organic world. P. Maupertuis (1698-1759) expresses brilliant guesses about the corpuscular nature of heredity, the evolutionary role of the destruction of forms that are not adapted to existence, the importance of isolation in the development of new forms. Charles Darwin's grandfather E. Darwin (1731-1802) in a poetic form affirms the principle of the unity of origin of all living beings, indicates that the organic world has been developing for millions of years. C. Linnaeus in the last years of his life also came to the recognition of evolution, believing that closely related species within the genus developed naturally, without the participation of divine power.

In the second half of the XVIII century. The Age of Enlightenment also reaches Russia: in one form or another, evolutionary views are characteristic of such natural scientists as M. V. Lomonosov, K. F. Wolf, P. S. Pallas, A. N. Radishchev. M. V. Lomonosov in his treatise “On the Layers of the Earth” (1763) wrote - “... many people think in vain that everything, as we see, was first created by the creator ...”.

Characterizing the development of evolutionary thought in this era, we can say that at this time there was an intensive accumulation of natural scientific material. The most perspicacious researchers are trying to move from a simple description of the material available in nature to an explanation of the emergence of various forms. In the XVIII century. there is an ever-intensifying struggle between the old ideas of creationism (as a concept of the creation of the world) and the new - evolutionary ideas.