What is the evolutionary significance. What is human evolution? What is the evolutionary role of selection

04.12.2019

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 of constant 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 one can find the idea of a gradual change in organisms 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 the well-known fact of the selection of producers in animal husbandry. In the modern era, the unwarranted application of these ideas to human society has developed into the doctrine of eugenics, which underlies the racial politics of the Third Reich.

Medieval and Renaissance

With the rise 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 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 there is not yet a word about the general theory. 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 bounded 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 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 opposed the existence of discrete species in a year, considering species to be the fruit of the imagination 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 talk 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 were considered side by side with fossils. Cuvier is rightfully considered a significant figure in the development of paleontology, biostratigraphy and historical geology as sciences. The theoretical basis for distinguishing the boundaries between the layers was Cuvier's idea of catastrophic extinctions of faunas and floras at the boundaries of periods and epochs. He also developed the doctrine of correlations (italics by N.N. Vorontsova), thanks to which he restored the appearance of the skull as a whole, the skeleton as a whole, and, finally, gave a reconstruction of the external appearance of a fossil animal. Together with Cuvier, his French colleague paleontologist and geologist A. Brongniard (1770-1847) made his contribution to stratigraphy, and, independently of them, 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 the monograph Ship Timber and Tree Plantation. 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. The English philosopher and historian of science William Whewell (1794-1866) in 1832 put forward the term uniformitarianism in relation to the assessment of 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 for so long give a satisfactory schematic explanation of geological facts in the eyes of the best researchers and thinkers, if it were not 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 aside from the discussion that unfolded in England, but he carefully watched how criticism of private inaccuracies turned into criticism of the very idea of \u200b\u200bthe variability of species, so as not to repeat similar mistakes. 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 famous work was published, 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 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 the work, with his geometric progression of 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 (within 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 urgent persuasion 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 the works of his predecessors, 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 "Possibility of changing plant species 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 indeterminate variability of organisms (mutations) is inherited and can become the beginning of a new breed or variety, if it is useful to man. Transferring this 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 norm of the species 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 ideas about the 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 recessivity) 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 it was Bronn who translated Darwin’s book into German, who did not share his views, but who believes that the new idea has the right to exist (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 monophilia - 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 say that they are finding more and 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, based not only on external similarity, but also on the structure of the 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 of the chromosome theory of 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 - the most important stage of 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 whole 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 among themselves. Most modern concepts"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. Weismann's harsh criticism of this concept caused him personally and his theory, and then to the study of chromosomes in general, a negative attitude on the part of 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 cytological substantiation to Mendelism: diploid and haploid sets, homologous chromosomes, the process of conjugation 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, was based on accurate calculations of Mendeleev 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 speciation in plants.

If in the middle of the 18th century the contradiction between transformism (continuous change) and the discreteness of taxonomic units of systematics seemed insurmountable, 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. The theory considers a holistic phenotype as the main substrate of natural selection, 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. Passed down from ancestors to descendants general organization ES, 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 it becomes possible development organisms along deviant paths of development, multiple morphoses arise. Some of these morphoses receive a selective advantage, and during subsequent generations their ES develops a new sustainable 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. Ecosystem - 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 part of society, almost from the moment of the birth of evolutionary biology, there has been a certain opposition to this doctrine 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 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, alien, therefore, 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, the evolutionary doctrine can be aimed at denying the existence of extra-natural forces, or rather their interference in the process of development of the living world, which one way or another implies 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 just 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 rejecting almost all the conclusions of the natural sciences that 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 (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 do homologous series lead? // Knowledge is power. - 1972. - № 8.

External links

Official website of the State Darwin Museum
N. N. Vorontsov. Ernst Haeckel and the fate of Darwin's teachings
Article "Evolution as resistance to entropy"
"What is evolution like?" (article on symbiosis and gene exchange)
A. S. Rautian.

Questions on evolution_level "C"

Find errors in the text, name the numbers of sentences in which errors were made. Explain them.

1. Scientists believe that eukaryotes were the first organisms to appear on Earth.

2. The first organisms were anaerobic heterotrophs.

3. Then evolution went towards the development of autotrophic ways

4. The first autotrophic organisms were algae and bryophytes.

5. As a result of photosynthesis, free oxygen appeared in the Earth's atmosphere.

Mistakes were made in sentences 1.4.

1 - prokaryotes; 4 - chemosynthetic bacteria.

Isolation consists in the appearance of barriers to interbreeding between individuals of different populations of the same species. In isolated populations, such a random process as the occurrence of mutations can proceed differently. The direction of natural selection can also be different. Over tens or hundreds of thousands of generations, isolated populations can accumulate significant differences, due to which individuals from different populations will lose the ability to interbreed. In this case, we can talk about the formation of new species. If populations are not isolated from each other, but, on the contrary, exchange hereditary information, then the emergence of significant differences and the formation of new species on their basis is impossible.

Microorganisms are able to quickly adapt to changing environmental conditions. What are the mechanisms of such high adaptability?

Response elements:

1) microorganisms multiply rapidly, and their populations consist of a very large number of individuals;

2) therefore, in the populations of microorganisms accumulates a large number of mutations that are the material for natural selection;

3) bacteria are haploid and mutations always appear in them, which speeds up the selection process;

4) in addition, microorganisms have a “horizontal” gene transfer using plasmids, that is, one individual can transfer its properties to other members of the population.

What is the evolutionary significance of indirect development?

It consists in weakening the competition between parents and offspring. Larvae and adults often occupy different habitats and/or use different food resources.

Why are populations the unit of evolution?

Because the population is the structural unit of the species, i.e. the smallest group of individuals capable of evolutionary development. Evolution occurs only in a group of individuals, since the genotype of one organism cannot change during life, and a group of individuals (isolated from other groups) can change, since it is a heterogeneous mixture of different genotypes. The reason for the evolution of populations may be their isolation, changes in habitat conditions, competition with other populations of the species (or with other species), changes in population size.

How can one explain the coincidence of the shape of some flowers with the shape of the body of insects or with the shape of its individual parts?

This is due to the long co-evolution of plants and insects. Natural selection retained both the best pollinators and the plants that were pollinated by insects whose shapes matched the shape and size of the flower. Some plant species as a result are pollinated only by certain pollinators, for example, clover is pollinated by bumblebees.

What are the main provisions of the synthetic theory of evolution?

The synthetic theory of evolution expands the teachings of Ch. Darwin about the causes and driving

forces of the evolutionary process. This theory distinguishes micro- and macroevolution, determines the criterion for the type of form of natural selection. The main evolving unit is the population, the factors of evolution are the mutation process, population waves, isolation, gene drift. The driving forces of evolution are heredity, variability, natural selection. Natural selection is divided into several forms, among which are the driving and stabilizing. The final stage of microevolution is the formation of new species. Larger systematic groups appear by aromorphoses. It should be noted that the causes and possible mechanisms of the evolutionary process are actively discussed by modern science.

What is the difference between natural and artificial selection?

Artificial selection, being the guiding factor of evolution, plays a leading role in the emergence of the diversity of the organic world.

As a result of natural selection, new species arise, as a result of artificial selection, varieties and breeds.

The criterion of natural selection is the adaptability of the species. The criterion of artificial

selection is the usefulness of the trait to the individual.

Natural selection has been going on on Earth since the beginning of life. Artificial

selection has arisen since the advent of domestic animals and agriculture.

Artificial selection is carried out in a much shorter time and often leads to the appearance of completely new plants and animals, the emergence of which is impossible under natural conditions.

What are the evolutionary consequences of isolating a small population?

Response elements:

1) crossing in a small isolated population leads to an increase in the level of homozygotes;

2) this leads to a decrease in the overall viability of the population due to homozygosity for many recessive alleles;

3) on the other hand, an increase in the level of homozygosity provides new material for natural selection, which can lead to the consolidation of new traits.

What are the main differences between the theories of J.B. Lamarck and C. Darwin?

J.B. Lamarck believed that acquired traits are inherited, that inherited changes are always beneficial, and the influence of the external environment that causes this change is always positive.

The evolutionary doctrine of Darwin refuted these provisions of Lamarck's theory. Traits acquired during life are not inherited, both beneficial and harmful and indifferent mutations can be hereditary, and the influence of the external environment on organisms can be both positive and negative.

Why are homologous organs considered one of the evidence for evolution?

These bodies have representatives different groups have a common origin.

Define aromorphosis, give 1-2 examples and prove that it is aromorphosis.

Aromorphosis is a spasmodic, sudden mutation that leads to an increase in the general level of organization of living beings. As a rule, aromorphoses contribute to the emergence of changes leading to the emergence of new systematic groups. Thus, for example, the emergence of photosynthesis ensured the gradual flourishing of various plant divisions; the appearance of a four-chambered heart in birds and mammals contributed to the development of warm-bloodedness, and, consequently, the conquest by these animals of almost all geographic regions of the Earth

Why are adaptations to environmental conditions relative?

When environmental conditions change, existing devices can be useless and even harmful.

What is the role of crossing over in the evolutionary process?

Crossing over - the crossing of homologous chromosomes in meiosis, leads to a variety of gametes and, as a result, genetic combinations in offspring. This, in turn, provides the opportunity for natural selection to operate and for a greater variety of adaptations to environmental conditions.

If, as a result of a violation of the crossover process, the structure of the chromosome changes, this can lead to the formation of pathological gametes and the development of hereditary diseases in the offspring.

Find the mistakes in the text. Indicate the numbers of the proposals in which they are made, explain them.

1. The most important aromorphoses in the evolution of multicellular organisms were: the development of movable jaws, the formation of five-fingered limbs, the emergence of protective coloration.

2. With the release of animals on land, external fertilization arose.

3. The flowering of mammals was ensured by the emergence of warm-bloodedness, a three-chambered heart and an internal skeleton.

Mistakes were made in sentences 1, 2, 3.

1. The most important aromorphoses in the evolution of multicellular organisms were: the development of movable jaws, the formation of five-fingered limbs, the emergence of protective coloration.

2. With the release of animals on land, external fertilization arose.

3 The flowering of mammals was ensured by the emergence of warm-bloodedness, a three-chambered heart and an internal skeleton.

What types of paleontological finds provide evidence for evolution?

Response elements:

1) fossils and prints

2) transitional forms

3) phylogenetic series

Why does a high abundance of a species contribute to biological progress?

Response elements:

1) the possibility of free crossing increases

2) the exchange of genetic material increases, heredity is enriched

What impact did the creation of evolutionary theory have on the formation of the modern natural-scientific picture of the world?

The evolutionary theory approved and proved the historical development of living nature, the variability of species

What aromorphoses allowed the ancient amphibians to master the land?

Response elements:

1) the appearance of pulmonary respiration

2) the formation of dissected limbs

3) the appearance of a three-chambered heart and two circles of blood circulation

Why is the resistance of insect pests to pesticides increasing?

1) Due to the appearance of mutations, the population of insect pests becomes heterogeneous.

2) Natural selection preserves individuals resistant to pesticides.

3) From generation to generation, the number of individuals resistant to pesticides is increasing.

4) After a few years, the pesticide in the same doses ceases to act on insect pests.

What processes confirm that life in the Proterozoic becomes a geological factor?

Living organisms participated in the formation of sedimentary rocks and iron ores.

Bee-like flies, which do not have a stinging apparatus, are similar in appearance to bees. Explain the emergence of mimicry in these insects on the basis of evolutionary theory.

Response elements:

1) insects of different species have similar mutations in external features (color, body shape);

2) individuals with traits that enhance their resemblance to protected insects were more likely to survive in the struggle for existence;

3) as a result of natural selection, such insects were less often pecked by birds and spread in the population.

In the industrial regions of England during the 19th-20th centuries, the number of birch moth moths with dark-colored wings increased compared to light-colored moths. Explain this phenomenon from the standpoint of evolutionary teaching and determine the form of selection.

Response elements:

1) in the offspring of a population of butterflies, both light and dark forms are born;

2) in industrial areas polluted with soot, light individuals are eliminated from darkened trunks by birds, so butterflies with a dark color have become the predominant form in populations;

3) color change in a population of butterflies - a manifestation of the driving form of natural selection.

Why is the high abundance of a species an indicator of biological progress?

Response elements:

1) the possibility of free crossing increases;

2) the exchange of genetic material is enhanced and heredity is enriched;

3) contributes to the distribution of individuals and the expansion of the range.

Explain why people of different races are classified as the same species?

Response elements:

1) people of different races contain the same set of chromosomes in their cells;

2) from interracial marriages children will be born who, when they reach puberty, are able to reproduce;

3) people of different races are similar in structure, life processes, development of thinking.

The house mouse is a mammal of the genus Mice. Initial range - North Africa, tropics and subtropics of Eurasia; followed by man spread everywhere. Lives in natural conditions, feeds on seeds. Leads a nocturnal and twilight lifestyle. Usually 5 to 7 babies are born in a litter. What type criteria are described in the text? Explain the answer.

Response elements:

1) geographical criterion - area;

2) ecological criterion - nutritional characteristics, changes in activity during the day, living in certain environmental conditions;

3) physiological criterion - the number of cubs in the litter.

What aromorphoses led to the emergence of the phylum Arthropoda?

Response elements:

1) the appearance of the external skeleton;

2) the emergence of jointed limbs;

3) the emergence of striated muscles.

What type of natural selection is aimed at preserving mutations that lead to less variability in the average value of a trait?

stabilizing selection.

What is the unit of evolution according to the synthetic theory of evolution (STE)?

population.

What characterizes biological progress?

Response elements:

1) an increase in the number of individuals of this systematic group;

2) expansion of the range;

3) expansion of species diversity within a group (populations and subspecies within a species, species within a genus, etc.).

What social factors are the driving forces of anthropogenesis?

Response elements:

1) labor activity;

2) social way of life;

3) speech and thinking.

What evidence is there for the origin of humans from animals?

Response elements:

1) common features of the structure of humans and animals;

2) similarities in the development of human and animal embryos;

3) the similarity of man and great apes.

What does the hypothesis (law) of purity of gametes imply?

During the formation of germ cells, only one allele from an allelic pair enters each gamete, that is, the gametes are genetically pure.

Name the type, explain the significance of the protective coloration, as well as the relative fitness of the flounder, which lives in sea waters near the bottom.

Response elements:

1) type of coloration - patronizing - merging with the background of the seabed;

2) the ability to change the color of the upper side of the body makes the fish invisible against the background of the ground, allowing you to hide from enemies and possible prey;

3) fitness is broken when the fish moves, and it becomes available to enemies.

Explain why atavisms appear in certain people?

Response elements:

1) believe that a person is of animal origin;

2) signs of ancient ancestors (atavisms) are embedded in the human genome;

3) in rare cases, a person has a violation of the individual development of the body, signs of animal ancestors appear.

Name the type of protective device, explain its significance and relative nature in the moth caterpillar, which lives on the branches of trees and at the moment of danger becomes like a twig.

Response elements:

1) type of adaptation - imitation of the motionless bodies of nature (imitative similarity), protective coloring and shape - disguise;

2) the caterpillar freezes motionless on a branch and becomes like a twig and invisible to insectivorous birds;

3) fitness becomes useless when the caterpillar moves or the background of the substrate changes /

What are the aromorphoses that accompanied the evolution of reptiles during their development of land

Response elements:

1) transition to only lung breathing;

2) the appearance of dry keratinized skin without glands;

3) internal fertilization, the emergence of embryonic and egg membranes

Name the type of protective device against enemies, explain its significance and relative nature in a small seahorse fish that lives at a shallow depth in the environment of aquatic plants.

Response elements:

1) the similarity of an animal with an immovable natural object - a plant is called a patronizing similarity (disguise);

2) a seahorse hangs among aquatic plants and is invisible to predators;

3) when the fish moves or in open space, it becomes accessible and noticeable to enemies.

Explain the changes that have occurred in the structure of the limb and the way the horse moves during evolution. What environmental conditions of the ancestors of horses caused this?

Response elements:

1) the number of fingers decreased from multi-fingered to one;

2) fast running became the main mode of movement;

3) the ancestors of the horse moved from life among dense vegetation to life in open spaces.

What differences in the structure of the human body and great apes arose in the process of evolution?

Many differences are due to the adaptation of a person to walking upright: S-shaped spine, arched foot, wide pelvis, flat wide rib cage, massive lower limbs, shorter and thinner bones upper limbs and others. The transformation of the human hand from a support organ into a labor organ made the hand more mobile.

Vivid differences between humans and great apes are observed in the structure of the skull and brain. The brain part of the skull in humans prevails over the front. In monkeys, on the contrary, the facial part, especially the jaws, is highly developed. The human skull does not have continuous superciliary ridges and bone ridges, the forehead is high and convex, the jaws are weak, the fangs are small, and there is a chin protrusion on the lower jaw. The human brain in terms of volume and mass is 2-2.5 times larger than the brain of great apes. The parietal, temporal and frontal lobes of the cerebral hemispheres, in which the most important centers of mental functions and speech are located, are much more developed in humans.

An example of what way to achieve biological progress (aromorphosis, idioadaptation or general degeneration) is the variety of finches described by Charles Darwin on the Galapagos Islands?

This is an example of idioadaptation. Different types finches, having a similar level of organization, were able to acquire properties that allowed them to occupy completely different ecological niches in natural communities. Some species of finches have mastered feeding on the fruits of plants, others on seeds, and others have become insectivorous.

We formulate the answer: “In connection with adaptation to different food sources, the shape of the beak has changed in finches. This small adaptation did not increase their level of organization, and therefore is an idioadaptation.

Why is isolation in the modern theory of evolution considered an important condition for the formation of new species?

Which of the species criteria is the main one in determining the species belonging of an individual?

None of the view criteria can be absolute. For example, most often a morphological criterion is used to determine whether an individual belongs to a particular species. However, sometimes the species are outwardly almost indistinguishable, although in nature they are rigidly isolated and do not interbreed. These are twin species with a different number of chromosomes, which serves as an insurmountable obstacle to their crossing. Reliable enough genetic criterion. But there are cases when species have chromosomes that are practically indistinguishable in structure. In addition, chromosomal mutations can be widespread within a species, making it difficult to accurately identify the species.

Therefore, each criterion separately cannot be the basis for determining the species; only in the aggregate they allow us to accurately determine the species affiliation of an individual.

Under what conditions does stabilizing selection operate in natural populations?

Stabilizing selection acts as long as the living conditions of the population do not change significantly.

What is the significance of mutations in the evolutionary process?

Mutations create the basis for the action of other evolutionary factors, primarily natural selection. Most mutations are harmful to an organism, but harmful in some conditions, they may be beneficial in others. For example, a mutation that causes the reduction of wings in insects is harmful to them under normal land conditions, since it deprives them of the ability to fly. At the same time, it proved to be useful on oceanic islands, since here winged insects are picked up by the wind and carried into the sea. The mutation process leads to the emergence of that reserve of hereditary variability, which can provide the possibility of adapting a population to new conditions.

How many forms of the struggle for existence did Charles Darwin distinguish?

Darwin distinguished 3 forms of the struggle for existence: intraspecific, interspecific and struggle with adverse environmental conditions.

Is it possible to speak about the emergence of a new adaptation if individuals with new successful traits appeared in the population?

For the emergence of adaptation, the presence of elementary evolutionary material is necessary - hereditary variability. The appearance in a population of individuals with a new successful phenotype cannot yet be considered as an adaptation. We can talk about adaptation only after the emergence of a specialized trait in the entire population or species. This is achieved under the influence of various evolutionary factors, and primarily natural selection. It is selection that can turn specific useful deviations of individuals into the norm for the population as a whole.

What causes biological isolation between populations of the same species?

Biological isolation is due to a number of reasons: confinement to different habitats within the species range; difference in the behavior of animals of different populations during the breeding season, different times of sexual activity, the emergence of polyploids.

Why did the appearance of man become an event of great significance in the evolution of the biosphere?

Because gradually man turned into a powerful geological force that transforms the planet. The development of science and production allowed man to actively change the nature around him.

The body shape of the Kalima butterfly resembles a leaf. How did a similar body shape form in a butterfly?

the appearance of various hereditary changes in individuals;

preservation by natural selection of individuals with a modified body shape;

reproduction and distribution of individuals with a body shape resembling a leaf.

What organic substances provided reproduction management of organisms during the origin of life?

Nucleic acids are capable of replication, that is, the creation of new copies indistinguishable from parent molecules. Answer: Nucleic acids.

Why, when determining whether an individual belongs to one or another type take into account the complex of crite reev?

Criteria characterizing the species: morphological, genetic, physiological, biochemical, physiological, ecological, geographical. There are species that are similar in one or more criteria, therefore, in order to determine a species, it is necessary to take into account the totality of all its criteria.

Answer: None of the criteria alone gives a complete characterization of the species.

What is the convergent similarity of Croco dila, frogs and hippopotamus?

All named animals most lives are spent in the water. Being in the water, they expose the eyes and nostrils located on the top of the head above its surface, while getting the opportunity to better navigate and breathe air oxygen.

Answer: Similar arrangement of eyes and nostrils on the head.

Why are people of different races classified as the same species?

Race - a historically formed group of people, characterized by a commonality of hereditary physical features (color of skin, eyes and hair, eye shape, etc.).

Answer:

due to the similarity of the structure, life processes, behavior;

due to genetic unity - the same set of chromosomes;

interracial marriages produce offspring capable of reproduction.

What is the advantage of the development of the first living organisms of the Earth in the hydrosphere?

The hydrosphere protected living organisms from ultraviolet rays.

The absence of what component of the environment prevented the development of life on land in the early stages of evolution?

Lack of oxygen

What are laboratory-derived coacervates?

Accumulations of protein molecules

What is the result of the struggle for existence?

Natural selection.

What is the role of the driving forces of evolution in shaping the fitness of organisms?

1) Due to mutations and reproduction, the population becomes heterogeneous.

2) In the population there is a struggle for existence, which exacerbates the relationship of individuals.

3) Natural selection acts on the population, which contributes to the preservation of individuals with useful hereditary changes to life in certain conditions, ensuring their adaptability to the environment.

What is the significance of hereditary variation in evolution?

1) Due to hereditary variability, heterozygosity, the genetic heterogeneity of individuals in a population, increases, as a result of which the efficiency of natural selection increases.

2) When conditions change, natural selection will contribute to the preservation of individuals with hereditary changes that are useful under given conditions and may lead to the formation of a new species or fitness.

3) Due to the genetic heterogeneity of populations due to hereditary variability, it can quickly change in accordance with the guiding action of natural selection.

Why does a decrease in the range of a species lead to biological regression?

1) The ecological diversity of the environment is depleted due to the reduction of the range.

2) Unwanted inbreeding occurs.

3) Competition with other species and within the species is intensifying.

In the article, we will consider in detail the types of evolution, and also talk about this process as a whole, trying to comprehensively understand the topic. We will learn about how the doctrine of evolution was born, what ideas it is represented and what role the species plays in it.

Introduction to the topic

The evolution of the organic world is a rather complex and lengthy process that simultaneously takes place on different levels of organization of living matter. At the same time, it always affects many areas. It so happened that the development of wildlife occurs from lower forms to higher ones. Everything simple over time becomes more complex and takes on a more interesting form. Individual groups of organisms develop adaptive skills that allow living beings to exist better in their specific conditions. For example, in some aquatic animals, webs between the fingers appeared as a result of the evolution.

Three Directions

Before talking about the types of evolution, let's consider three main directions identified by prominent Russian scientists I. Schmalhausen and A. Severtsov. In their opinion, there is aromorphosis, idioadaptation, degeneration.

Aromorphosis

Aromorphosis, or arogenesis, is a serious evolutionary change that generally leads to a complication of the structure and functions of some organisms. This process allows you to fundamentally change some aspects of life, such as habitats. Aromorphosis also contributes to an increase in the competitiveness of specific organisms for survival in the environment. The main essence of aromorphoses is the conquest of new adaptive zones. That is why such processes occur quite rarely, but if they do happen, they are of a fundamental nature and affect all further development.

In this case, it is necessary to understand such a concept as the adaptation level. This is a specific area of habitat with a characteristic climate and environmental conditions that are characteristic of a particular group of organisms. For example, for birds, the adaptive zone is the airspace, which protects them from predators and allows them to learn new ways of hunting. In addition, movement in the air makes it possible to overcome large obstacles and carry out long-distance migrations. That is why flight is rightfully considered an important evolutionary aromorphosis.

The most striking aromorphoses in nature are multicellularity and sexual reproduction. Thanks to multicellularity, the process of complicating the anatomy and morphology of almost all organisms began. Thanks to sexual reproduction, adaptive abilities have significantly expanded.

In animals, such processes contributed to the creation of more effective ways nutrition and improved metabolism. At the same time, warm-bloodedness is considered the most significant aromorphosis in the animal world, due to which the survival rate in different conditions has greatly increased.

In plants, such processes are manifested in the appearance of a common and conductive system that connects all their parts into a single whole. This increases the efficiency of pollination.

For bacteria, aromorphosis is an autotrophic way of feeding, thanks to which they were able to conquer a new adaptation zone, which can be deprived of organic food sources, and the bacteria will still survive on it.

Idioadaptation

Without this process, it is impossible to imagine the evolution of biological species. It implies specific adaptations to specific environmental conditions. In order to better understand what this process is, let's think a little. Idioadaptation is a small change that significantly improves the life of organisms, but does not bring them to a new level of organization. Consider this information on the example of birds. The wing is a consequence of the process of aromorphosis, but the shape of the wings and the methods of flight are already idioadaptations that do not change anatomical structure birds, but at the same time are responsible for their survival in a certain environment. The color of animals can also be attributed to such processes. Due to the fact that they significantly affect only a group of organisms, they are considered signs of species and subspecies.

Degeneration or catagenesis

Macro- and microevolution

And now let's go directly to the topic of our article. What are the types of this process? This is micro and macro evolution. Let's talk about them in more detail. Macroevolution is the process of formation of the largest systematic units: species, new families, and so on. The main driving forces of macroevolution lie in microevolution.

First, it is heredity, natural selection, variability and reproductive isolation. The divergent nature is characteristic of micro- and macroevolution. At the same time, these concepts that we are talking about now have received many different interpretations, but so far a final understanding has not been achieved. One of the most popular is that macroevolution is a systemic change that does not require a lot of time.

However, as far as the study of this process is concerned, it takes a very long time. Moreover, macroevolution is global in nature, so it is very difficult to master all its diversity. An important method of studying this area is computer modeling, which began to develop especially actively in the 1980s.

Types of Evidence for Evolution

Now let's talk about what evidence exists for macroevolution. Firstly, it is a comparative anatomical system of inference, which is based on the fact that all animals have a single type of structure. This is what indicates that we all have a common origin. Here much attention is paid to homologous organs, as well as atavisms. Atavisms of a person are the appearance of a tail, multiple nipples and a continuous hairline. An important proof of macroevolution lies in the presence of vestigial organs that are no longer needed by man and are gradually disappearing. The vestiges are an appendix, a hairline, and the remains of the third eyelid.

Now consider the embryological evidence that all vertebrates have embryos similar to early stages development. Of course, over time, this similarity becomes less and less noticeable, as character traits for a certain type.

Paleontological evidence for the process of evolution of species lies in the fact that the remains of some organisms can be used to study the transitional forms of other extinct creatures. Thanks to fossils, scientists can learn that there were transitional forms. For example, such a form of life existed between reptiles and birds. Also, thanks to paleontology, scientists were able to build phylogenetic series in which one can clearly trace the sequence of successive species that develop in the process of evolution.

Biochemical evidence is based on the fact that all living organisms on earth have a uniform chemical composition and the genetic code, which should also be noted. Moreover, we are all similar in energy and plastic exchange, as well as the enzymatic nature of some processes.

Biogeographic evidence is based on the fact that the process of evolution is perfectly reflected in the nature of the distribution of animals and plants on the surface of the Earth. So, scientists conditionally divided the mass of the planet into 6 geographical zones. We will not consider them in detail here, but we will note that there is a very close relationship between continents and related species of living organisms.

Thanks to macroevolution, we can understand that all species have evolved from previously living organisms. Thus, the essence of the development process itself is revealed.

Transformations at the intraspecific level

Microevolution refers to small changes in alleles in a population over generations. It can also be said that these transformations occur at the intraspecific level. The reasons lie in mutation processes, artificial and natural drift and gene transfer. All these changes lead to speciation.

We have considered the main types of evolution, but we do not yet know that microevolution is divided into some branches. First, it is population genetics, thanks to which the mathematical calculations necessary to study many processes are made. Secondly, it is ecological genetics, which makes it possible to observe developmental processes in reality. These 2 types of evolution (micro- and macro-) are of great importance and make their definite contribution to the development processes as a whole. It is worth noting that they are often opposed to each other.

Evolution of modern species

To begin with, we note that this is an ongoing process. In other words, it never stops. All living organisms evolve at different rates. However, the problem is that some animals live very long, so it is very difficult to notice any changes. To trace them, hundreds or even thousands of years must pass.

IN modern world there is an active evolution of African elephants. True, with the assistance of a person. So, in these animals, the length of the tusk is rapidly decreasing. The fact is that hunters have always hunted elephants, which had massive tusks. At the same time, they were much less interested in other individuals. Thus, they had an increased chance of survival, as well as of passing on their genes to other generations. That is why, over the course of several decades, a decrease in the length of the tusks was gradually noted.

It is very important to understand that the absence of external signs does not mean the end of the process of evolution. For example, very often different researchers are mistaken about the cross-finned coelacanth fish. There is an opinion that it has not evolved for millions of years, but this is not so. We add that today the coelacanth is the only living representative of the coelacanth order. If we compare the first representatives of this species and modern individuals, we can find many significant differences. The only similar feature is in external signs. That is why it is very important to take a comprehensive look at evolution, not to judge it solely by external signs. Interestingly, modern coelacanth has more similarities with herring than with its progenitor coelacanth.

Factors

As we know, species have evolved, but what factors contributed to this? First, hereditary variability. The fact is that various mutations and new combinations of genes create the basis for hereditary diversity. Note: the more active the mutation process, the more effective natural selection will be.

The second factor is the random persistence of features. To understand the essence of this phenomenon, let's deal with such concepts as genetic drift and population waves. The latter are fluctuations that occur in periods and affect the size of the population. For example, every four years there are a lot of hares, and immediately after that their number drops sharply. But what is genetic drift? This implies the preservation or disappearance of any signs in a random order. That is, if as a result of some events the population is greatly reduced, then some features will be preserved in whole or in part in a chaotic manner.

The third factor we will consider is the struggle for existence. Its reason lies in the fact that a lot of organisms are born, but only a fraction of them are able to survive. Moreover, there will not be enough food and territories for everyone. In general, the concept of the struggle for existence can be described as a special relationship of the organism with the environment and other individuals. In this case, there are several forms of struggle. It can be intraspecific, which occurs between individuals of the same species. The second form is interspecific, when representatives of different species are fighting for survival. The third form is the struggle with environmental conditions, when animals need to adapt to them or die. At the same time, the struggle within the species is rightfully considered the most cruel.

Now we know that the role of the species in evolution is enormous. It is from one representative that a mutation or degeneration can begin. However, the evolutionary process is regulated by itself, as the law of natural selection operates. So, if new signs are ineffective, then individuals with them will die sooner or later.

Let us consider one more important concept, which is characteristic of all types of driving evolution. This is isolation. This term implies the accumulation of certain differences between representatives of the same population, which has been isolated from each other for a long time. As a result, this can lead to the fact that individuals simply cannot interbreed with each other, thus two completely different species will appear.

Anthropogenesis

Now let's talk about the types of people. Evolution is a process characteristic of all living organisms. The part of biological evolution that led to the emergence of man is called anthropogenesis. This resulted in the separation human species from great apes, mammals and hominids. What kinds of people do we know? Evolutionary theory divides them into Australopithecus, Neanderthals, etc. The characteristics of each of these species are familiar to us from school.

So we got acquainted with the main types of evolution. Biology can sometimes tell a lot about the past and the present. That is why it is worth listening to. Note: some scientists believe that 3 types of evolution should be distinguished: macro-, micro- and human evolution. However, such opinions are isolated and subjective. In this material, we presented to the reader's attention 2 main types of evolution, thanks to which all living things develop.

Summing up the article, let's say that the evolutionary process is a real miracle of nature, which itself regulates and coordinates life. In the article we examined the basic theoretical concepts, but in practice everything is much more interesting. Each biological species is a unique system capable of self-regulation, adaptation and evolution. This is the beauty of nature, which took care not only of the created species, but also of those into which they can mutate.

Progress and regression in evolution. The evolutionary process as a whole is continuously moving towards the maximum adaptation of living organisms to environmental conditions. Changing conditions often lead to the replacement of one device by another. However, the same applies to adaptations of a broad nature, which give organisms advantages in various environmental conditions. Such, for example, is the importance of the lungs as a universal organ of gas exchange in terrestrial vertebrates, or of a flower as a perfect reproductive organ in angiosperms. Thus, biological progress can be carried out as a result of both private and general adaptations of organisms. Biological progress should be understood as an increase in the adaptability of organisms to the environment, leading to an increase in the number and wider distribution of the species.

Evolutionary changes occurring in some species and larger taxa (families, orders) cannot always be recognized as progressive. In such cases, one speaks of biological regression. Biological regression is a decrease in the level of adaptability to living conditions, a decrease in the number of species and the area of the species range.

What are the ways to achieve biological progress?

Aromorphosis. Question about possible ways Achieving biological progress was developed by A. N. Severtsov, a prominent evolutionary scientist. One of the main such ways, according to Severtsov, is morphophysiological progress, or aromorphosis, i.e., the appearance in the course of evolution of signs that significantly increase the level of organization of living organisms. Aromorphoses give great advantages in the struggle for existence, open up the possibility of mastering a new, previously inaccessible habitat.

ALEXEY NIKOLAEVICH SEVERTSOV (1866-1936) - Russian evolutionist. Author of studies on comparative anatomy of vertebrates. Created the theory of morphophysiological and biological progress and regression.

In the evolution of mammals, several major aromorphoses can be distinguished: the appearance of a coat, live birth, the feeding of young with milk, the acquisition constant temperature body, progressive development of the lungs, circulatory system and brain. The high general level of organization of mammals, achieved due to the listed aromorphic changes, allowed them to master all possible habitats and eventually led to the emergence of higher primates and humans.

The formation of aromorphosis is a long process occurring on the basis of hereditary variability and natural selection. Morphophysiological progress is the main path of the evolution of the organic world. In the development of each major taxonomic group, aromorphoses can be found, which you will learn about from the following material.

Idioadaptation. In addition to such a major transformation as aromorphosis, in the course of the evolution of individual groups, a large number of small adaptations to certain environmental conditions arise. A. N. Severtsov called such adaptive changes idioadaptation.

Idioadaptations are adaptations of the living world to the environment, opening up the possibility of progressive development for organisms without a fundamental restructuring of their biological organization. An example of idioadaptation is the variety of finches described by Charles Darwin (Fig. 65). Different types of finches, having a similar level of organization, could, however, acquire properties that allowed them to occupy completely different places in nature. Some species of finches have mastered feeding on the fruits of plants, others on seeds, and others have become insectivorous.

Rice. 65. Variety of finches in the Galapagos Islands

Despite the fact that general degeneration leads to a significant simplification of organization, species following this path can increase their numbers and range, that is, move along the path of biological progress.

Correlation of directions of evolution. The paths of evolution of the organic world either combine with each other or replace each other. Moreover, aromorphosis occurs much less frequently than idioadaptation, but it is aromorphosis that determines new stages in the development of the organic world. Having arisen by aromorphosis, new, higher in organization groups of organisms occupy a different habitat. Further, evolution follows the path of idioadaptation, and sometimes degeneration, which provide organisms with a new habitat for them (Fig. 67).

Rice. 67. Scheme of relationships between aromorphosis, ideological adaptation and degeneration

So, let's list the general features of the evolutionary process. First of all, this is the emergence of the adaptability of organisms, that is, their compliance with the conditions of their habitat and the ability to change as these conditions change. Natural selection of hereditary changes in natural populations is the most important cause of fitness.

Another important characteristic of the evolutionary process is speciation, that is, the constant emergence of new species. During evolution, there have been tens, and possibly hundreds of millions of species of living organisms on Earth.

And finally, the third inalienable property of the evolutionary process is the constant complication of life from primitive pre-cellular forms up to man.

Explain the terms: biological progress, biological regression, aromorphosis, idioadaptation.
Can the concepts of "biological regression" and "degeneration" be considered identical? Justify the answer.
What is the evolutionary significance of aromorphosis and idioadaptation?

What is the evolutionary significance. What is human evolution? What is the evolutionary role of selection

Medieval and Renaissance

Evolutionary ideas of modern times

Lamarck's theory

catastrophism and transformism

Evolutionists - contemporaries of Darwin

Proceedings of Darwin

Development of Darwin's ideas

Modern theories of biological evolution

Synthetic theory of evolution

Neutral theory of molecular evolution

Epigenetic theory of evolution

Ecosystem theory of evolution

Evolutionary doctrine and religion

Literature

see also

External links

Introduction to the topic

Three Directions

Aromorphosis

Idioadaptation

Degeneration or catagenesis

Macro- and microevolution

Types of Evidence for Evolution

Transformations at the intraspecific level

Evolution of modern species

Factors

Anthropogenesis

Report a typo

Text to be sent to our editors:

Your comment (optional):