2. Evolutionary theory of J. B. Lamarck Remember! What is evolution? What explains the dominance of ideas about the immutability of species in the era of C. Linnaeus? At the end of the 18th century. most scientists were ready to accept the idea of ​​species variability. The active accumulation of scientific

3. Prerequisites for the emergence of the teachings of Charles Darwin Remember! Who was the author of the first evolutionary theory? What biological discoveries were made by the middle of the 19th century? Natural scientific prerequisites. By the middle of the 19th century. Many new discoveries have been made in natural science.

2.5. Evolutionary biology and systematics The theoretical principles of evolutionary biology are fundamental to the principles of systematics. Outside of taxonomy there is no biology. Without taking into account systematics, not a single biological problem can be considered, including

11.5. Evolutionary psychology Evolutionary psychology is the only direction in psychology that adequately reflects the achievements of genetics and evolutionary biology. Its strength is its interdisciplinary approach. Analysis of the interaction of biological and

In 1859, the book of the English scientist Charles Darwin “The Origin of Species by Means of Natural Selection, or the Preservation of Favorable Breeds in the Struggle for Existence” was published. It immediately became a bestseller, topping the list of world-famous books and bringing its author the laurels of being the only discoverer of evolutionary theory. However, the latter is not only inaccurate, but also historically unfair in relation to other scientists, Darwin’s predecessors and contemporaries, as is proven in the next “evolutionary essay” published in our journal from the forthcoming book of the famous scientist and historian of science V.N. Soifer “ Evolutionary idea and Marxists".

Charles Darwin was born on February 12, 1809 - the year the Philosophy of Zoology by Jean Baptiste Lamarck was published, in which the first evolutionary theory was presented in detail and in detail.

Darwin did not excel at school. Things were also not going well at college, and in the end his father sent him away - to Scotland, where in October 1825 the 16-year-old boy began studying at the Faculty of Medicine at the University of Edinburgh (this choice of his son’s future specialty was not accidental - his father was a successful doctor ). After two years, it became clear that Charles would not be able to become a doctor. A new transfer followed - this time to another famous university, Cambridge, but to the Faculty of Theology. Charles himself recalled about studying there: “... the time I spent in Cambridge was seriously lost, and even worse than lost. My passion for rifle shooting and hunting... led me into a circle... of young people of not very high morality... We often drank to excess, and then funny songs and cards followed. ... I know that I should be ashamed of the days and evenings spent in this way, but some of my friends were such nice guys, and we all had so much fun that I still remember this time with pleasure.”

Finally, in May 1831, Darwin passed his baccalaureate examination. He was supposed to study at the faculty for two more semesters, but events turned out differently. Taking advantage of a rare opportunity, he hired, against the wishes of his father, on the Beagle, which was setting off on a voyage around the world under the command of Captain Robert Fitz Roy. Darwin's duties as a naturalist included collecting animals, plants, and geological specimens. Over five years, Darwin visited South America, the Pacific Islands, New Zealand, Australia and other parts of the globe.

The five-year trip around the world came to an end on October 2, 1836. Now Darwin had to begin describing the collections he had collected and publishing data about the trip. Three years later, his first book was published - “Voyage on the Beagle Ship” (or “Diary of Research”), which immediately brought enormous popularity to the young author. Darwin had a rare gift as a storyteller, able to highlight details and events, even those that were not very interesting at first glance.

Did it all start with Malthus?

When did Darwin first think about the problems of evolution? He himself mentioned many times that he came to his evolutionary hypothesis in 1842 and that he was inspired by this idea from the book of the great English economist Thomas Robert Malthus, “An Essay on the Law of Population” (1798). Malthus argued that the population on Earth is growing over time in geometric progression, but means of subsistence - only in arithmetic progression. Darwin claimed that this thesis struck him, and he translated this pattern to the whole of nature, suggesting that there is always a struggle for existence in it, since there are not enough sources of food and habitat for all those born.

The thesis about the existence of such a struggle between representatives of the same species ( intraspecific struggle), as well as between individuals of different species ( interspecies struggle), was Darwin's major innovation. He stated that evolution occurs due to the selection of individuals better adapted to the external environment ( natural selection). If there really is not enough space under the sun for all those born and the weak die in competition with the strong, then if some organism accidentally turns out to be more adapted to the environment, it will be easier for it to survive and produce more offspring. If the improved trait is retained by the descendants of the lucky one, then they will begin to crowd out their relatives less adapted to such an environment and reproduce faster. Nature will take a small step forward, and then, lo and behold, an even more fortunate person with an even more perfect structure will appear. And so - for millions of years, as long as life exists on Earth.

Darwin, according to him, began to think about the problems of species variability already during the voyage on the Beagle: “I came to the idea that species probably change from data on geographical distribution, etc., but over the course of several years I was helpless before the complete inability to propose a mechanism by which every part of every creature would be adapted to the conditions of their life.” Lamarck's idea of ​​gradual improvement of species had become quite popular by this time. Just as a drop chisels a stone, statements about natural development and the emergence of new species that have been repeated for decades have done their job and accustomed people to the idea that evolution is permissible. It is appropriate to recall Benjamin Franklin with his thesis about man turning into one from an animal thanks to the production of tools, and Charles’s famous grandfather, Erasmus Darwin, a doctor and publicist, who set out in his essay “Zoonomy, or the Laws of Organic Life” (1795) the idea of ​​organic progress.

Darwin repeatedly repeated (including in his declining years in his Autobiography) that the idea of ​​natural selection dawned on him in October 1838, when he came across Malthus’s book. However, he allegedly did not make the first draft of his hypothesis at the same time, but only 4 years later, in 1842. This manuscript, often mentioned by Darwin in letters to friends, was not published during his lifetime.

After Darwin’s death, his son Francis published the book “Fundamentals of the Origin of Species,” in which he included two previously unknown manuscripts of his father - the above-mentioned first draft of the hypothesis on 35 pages (allegedly written by his father in 1842) and a more extensive one (230 pages). .) text marked 1844. Why these works were not published during the author’s lifetime, although, as we will see later, there was an urgent need for this, it is now hardly possible to find out.

Unpublished manuscripts

By 1842–1844, during the decades that had passed since Lamarck published his work on evolution, many facts had accumulated in biology that were quite consistent with evolutionary ideas. The idea has strengthened, and society has matured to accept it.

This is evidenced by another, curious, example. In 1843 and 1845 In England, a 2-volume work by an anonymous author, “Traces of Natural History,” was published. It outlined the idea of ​​the evolution of the living world, pointed out the connection between related species, and cited the role of electricity and magnetism in this process as the reason for the change in species.

The author made the following analogy: metal filings form a characteristic pattern of a branched plant stem around one end of an electrical conductor or magnet pole and a pattern more similar to a plant root around the other. Therefore, it cannot be ruled out that plants arose this way, because electrical forces took part in their formation. Despite such superficial judgments, the author created a work that was read with unflagging interest.

One of Darwin's friends, writer and publicist Robert Chambers, sent him a copy of the sensational book, and Darwin read it with interest. Six years after the book was published, it became clear that Chambers was its author.

One letter from Darwin dates back to 1844, shedding light on the fact that it was in this year that he himself began to attach great importance to his thoughts about evolution, which was not the case before. He wrote a long letter to his wife Emma on June 5, 1844, in which he set out in lofty terms his will: in the event of his sudden death, to spend 400 pounds on finishing the just completed manuscript on evolution (the task was detailed - to select appropriate examples from books marked by Darwin, edit the text, etc.). On the other hand, it was in January of the same year, in a letter to the botanist Joseph Hooker, the son of the director of the Royal Botanic Garden and son-in-law of the then patriarch of geology, Charles Lyell, that Darwin said that he was thinking about the problem of variability of species.

Why did Darwin suddenly decide to address his wife with a special message? He actually complained about his health during these years (no diagnosis was made, and he remained sick for another 40 (!) years). It would seem that if he valued his idea of ​​evolution so much that he was ready to spend money on paying fees from the inheritance he left, then he would have to spend all available energy and time on bringing the main work to the final stage. But nothing of the kind happened. One after another, he published thick books about anything, but not about evolution. In 1845, the second, revised edition of the “Diary of Travel on the Beagle” was published, in 1846 - a volume on geological observations in South America, in 1851 - a monograph on barnacles, then a book on barnacles, etc. the essay on evolution lay motionless. What was Darwin waiting for? Why were you afraid to expose your work to criticism from your colleagues? Perhaps he was afraid that someone would see in his work borrowing from other people's works without reference to the true authors?

What Darwin did do, however, was often remind his high-ranking friends in letters that he spent all his free time thinking about the problem of evolution. Some of Darwin's recipients knew his main thesis in very general terms: there are not enough supplies of food, water and other means of subsistence for all those born, only those who have the potential to survive are kept alive. They are the ones who ensure progress in the living world.

Edward Blyth and his idea of ​​natural selection

Darwin's supporters later explained his strange slowness in publishing a work on evolution by the fact that he was allegedly absolutely convinced that this idea could not have occurred to anyone, which is why there was no reason to rush to publish the hypothesis, although his friends hurried Darwin with printing this work. This became clear from the surviving correspondence published after Darwin’s death (his son Francis reported that his father more than once carefully reviewed all his correspondence and selectively burned some of the letters).

However, it is unlikely that Darwin’s behavior is explained solely by unshakable confidence in his originality. In 1959, during the centennial celebration of the publication of On the Origin of Species, University of Pennsylvania anthropology professor Loren Eisley argued that Darwin had other reasons for delaying the publication of the evolutionary hypothesis for almost twenty years. According to Eisley, who carried out enormous research work, Darwin did not independently come to the idea of ​​the struggle for existence, but borrowed it, and not at all from the economist Malthus, but from the then famous biologist Edward Blyth, who was personally close to Darwin.

Blyth was a year younger than Darwin, grew up in a poor family and, due to his difficult financial situation, was able to finish only a regular school. To support himself, he was forced to go to work, and spent all his free time reading and diligently visiting the British Museum in London. In 1841 he received the post of curator of the Museum of the Royal Asiatic Society in Bengal and spent 22 years in India. Here he carried out first-class research into the nature of Southeast Asia. In 1863, due to a sharp deterioration in his health, he was forced to return to England, where he died in 1873.

In 1835 and 1837 Blyth published two articles in the Journal of Natural History in which he introduced the concepts of the struggle for existence and the survival of those more adapted to the environment. However, according to Blyth, selection does not proceed in the direction of increasingly improved creatures acquiring properties that give them advantages over already existing organisms, but in a completely different way.

The task of selection, according to Blyth, is to preserve the invariance of the basic characteristics of the species. He believed that any new changes in organs (now we would call them mutations) cannot bring anything progressive to already existing species that have been well adapted to the external environment over millions of years. Changes will only disrupt the well-established mechanism of interaction between the environment and organisms. Therefore, all newcomers, inevitably spoiled by the disorders that have arisen in them, will be cut off by selection, will not withstand competition with well-adapted typical forms and will die out. Thus Blyth applied the principle of selection to wildlife, although selection was given a conservative rather than a creative role.

Darwin could not help but know Blyth's works: he held in his hands issues of journals with his articles and quoted them. He wrote, more than once, that he carefully and carefully followed all publications concerning the development of life on Earth, and especially those close to him in spirit. He also cited many other works of Blyth, paying tribute to the merits of his colleague, so he could not ignore his works on natural selection. However, he never referred to the article in which Blyth clearly and clearly presented the idea of ​​​​the struggle for existence and natural selection.

Being proud and, as Eisley and a number of other historians believed, obsessed with the mania of shared glory, Darwin could take advantage of Blyth’s fundamental provisions, after which he began to put his notes in order. By 1844, he could actually prepare a rather voluminous manuscript on evolution, but, realizing the lack of originality of his work on the cornerstone issue of natural science, he waited, played for time, hoping that some circumstances would change something in the world and allow him to “save face” " That is why in his “Autobiography” he repeated once again: the only impetus for him to think about the role of natural selection was the book of Malthus. It was safe to refer to an economist, and not a biologist, who spoke about natural selection in the world of living beings several years earlier, because the priority in applying economic analysis to the situation in the biological world remained with the biologist, that is, with himself.

But even in this statement, meticulous historians found a stretch: although Darwin indicated the exact date when he read Malthus’s book (October 1838), neither in the essay of 1842, nor in the more voluminous work of 1844 did he refer to Malthus as he never once referred to the person who pushed him to the idea of ​​evolution, and in the place where he mentioned him, it was not at all about the idea of ​​competition.

Eisley found several more similar cases in which Darwin treated his direct predecessors indelicately and thus partly confirmed the correctness of the opinion expressed back in 1888 by Professor Houghton from Dublin about Darwin’s views regarding the origin of species: “Everything that was new in them was wrong, and what was right was already known.”

Apparently, this explains the mysterious fact of Darwin’s reluctance to publish a work on the origin of species for almost 20 years.

Evolutionary views of Alfred Wallace

Perhaps this work would have continued to remain in Darwin’s chest if one day an event had not occurred that forced him to urgently change his position. In 1858, he received by mail the work of his compatriot Alfred Wallace, who was at that moment far from England. In it, Wallace presented the same idea about the role of natural selection for progressive evolution.

From reading Wallace's work, Darwin realized that his competitor had developed the hypothesis of evolution even more extensively than he had, since he had included in his analysis not only the material on domestic animals, which Darwin had predominantly used, but also gleaned facts from the wild. Darwin was particularly struck by the fact that Wallace's main formulations were stated in the same words as in his "Essay on Evolution", and it was Wallace who referred to Malthus.

How could it be that a competitor described the same thing? Alfred Russell Wallace (1823–1913) spent many years collecting scientific collections on expeditions to the Amazon and Rio Negro rivers, the Malay Archipelago and other places (he amassed a collection containing 125 thousand botanical, zoological and geological specimens; compiled dictionaries 75 adverbs, etc.). Wallace began to think about the problem of the origin of species almost simultaneously with Darwin. In any case, already in 1848, in a letter to his friend, traveler Henry Bates, he wrote: “I would like to collect and thoroughly study representatives of any one family, mainly from the point of view of the origin of the species.”

It is strange that researchers of Darwinism rarely mention the most important fact for understanding the formation of Wallace’s evolutionary views: in September 1855, four years before the first edition of Darwin’s Origin of Species, Wallace published in “ Annals and Magazine of Natural History” article entitled “On the Law Regulating the Appearance of New Species.” In it, Wallace not only made a statement about the existence of the process of evolution of species, but also pointed out the role of geographic isolation in the formation of new varieties. He even formulated a law: “The appearance of each species coincides geographically and chronologically with the appearance of a species very close to it and preceding it.” His other thesis was also significant: “Species are formed according to the plan of previous ones.” He based these conclusions not only on data from studying collections of contemporary species, but also on fossil forms.

A. Wallace, who knew wild nature well, drew examples from his expedition observations. In the introduction to his book “Darwinism...” (1889) he writes: “The weak point in Darwin’s works has always been considered that he primarily based his theory on the phenomena of external variability of domesticated animals and cultivated plants. Therefore, I tried to find a solid explanation for his theory in the facts of the variability of organisms in natural conditions."

Wallace, as is usual in the scientific community, sent his article to fellow biologists, including Darwin, whom he highly valued for his description of the voyage on the Beagle. A traveler and naturalist, Wallace was well aware of the difficult task of describing the monotonous journeys from place to place and the repetitive activities of day after day. Two prominent scientists - Lyell and Blyth - also drew Darwin's attention to Wallace's article, as Darwin reported in a letter to Wallace dated December 22, 1857.

Darwin responded positively to Wallace's work, and from that time on, correspondence began between them. But Darwin, intentionally or unwittingly, dampened Wallace's energy in regard to further thinking about the problem of the origin of species when, in one of his letters, he casually informed him that he had been working on the same problem for a long time and was writing a large book on the origin of species. This message had an effect on Wallace, as he wrote in a letter to Bates: “I am very pleased with Darwin’s letter, in which he writes that he agrees with “almost every word” of my work. Now he is preparing his great work on species and varieties, for which he has been collecting material for 20 years. He can save me the trouble of writing further about my hypothesis... in any case, his facts will be placed at my disposal, and I can work on them.”

However, as all Darwin’s biographers unanimously testify, despite his promises, Darwin did not provide his hypotheses and the facts in his hands to Wallace. Thus, the prominent Russian biographer of Darwin A.D. Nekrasov writes: “...Darwin, citing the impossibility of expressing his views in a letter, kept silent about the theory of selection. Wallace came to the idea of ​​natural selection independently of Darwin.... Without a doubt, Darwin in his letters did not say a single word about either the principle of the struggle for existence or the preservation of the fittest. And Wallace came to these principles independently of Darwin.”

So, Wallace himself formulated the hypothesis of natural selection, and this happened on January 25, 1858, when the traveler was on one of the islands of the Moluccas archipelago. Wallace fell ill with a severe fever and, between attacks, suddenly clearly imagined how Malthus's reasoning about overpopulation and its role in evolution could be applied. After all, if Malthus is right, then the chances for better survival are higher for organisms that are better adapted to living conditions! In the “struggle for existence,” they will prevail over those less adapted, produce more offspring, and, due to better reproduction, occupy a wider area.

After this insight, a general picture quickly formed in the mind of Wallace, who had been thinking about the problems of species change for many years. Since he already had the basic facts, it was not difficult for him to hastily sketch out the theses of the article and also hastily complete the entire work, giving it a clear title: “On the tendency of varieties to move endlessly away from the original type.” He sent this article to Darwin at the first opportunity, asking for help with publication. As Nekrasov wrote, “Wallace sent it to Darwin, hoping that the application of the principle of the “struggle for existence” to the question of the origin of species would be as much news to Darwin as it was to himself.”

However, Wallace's assumption that Darwin would help popularize his work was a mistake and forever deprived him of his completely legitimate priority in publishing the principle of evolution through the selection of organisms best adapted to environmental conditions. Darwin not only did nothing to quickly publish Wallace's work, but also tried to take all measures to assert his primacy.

Hasty publication of Darwin's work

Having received Wallace's work, Darwin realized that he had been ahead of him. It is significant that in a letter to Lyell he admitted: “I have never seen such a striking coincidence; if Wallace had my 1842 manuscript, he could not have produced a better abridged review. Even its titles correspond to the titles of my chapters."

Having learned about what had happened, two of Darwin's friends, Charles Lyell and Joseph Hooker, who occupied a high position in the scientific circles of England, decided to save the situation and presented to the members of the Linnean Society of London both Wallace's completed work and Darwin's short (two pages) note “On the Tendency of Species.” to the formation of varieties and species through natural selection." Both materials were read on July 1, 1859 at a meeting of the society and then published under this date.

Darwin was not present at the meeting. There were two speakers - Lyell and Hooker. One of them eagerly, the other more restrainedly, said that they had witnessed Darwin’s creative torment and certified with their authority the fact of his priority. The meeting ended in deathly silence. Nobody made any statements.

By the end of the year, Darwin had completed On the Origin of Species and paid for its publication. The book was printed in two weeks; the entire circulation (1250 copies) was sold out in one day. Darwin hastily paid for the second edition, and a month later another 3,000 copies went on sale; then the third edition, corrected and expanded, was published, then the fourth, etc. Darwin's name gained enormous popularity.

Wallace, fully reconciled with the loss of priority, published the book “Contribution to the Theory of Natural Selection” in 1870, and in 1889 - a huge (750 pages) volume, symbolically called “Darwinism. An Exposition of the Theory of Natural Selection and Some of Its Applications".

The main purpose of these books was to illustrate with examples the principle of better survival of animals and plants that are more adapted to a given environment. Darwin largely used examples from the field of domestication of animals, breeding of livestock breeds, ornamental birds and fish, and selection of plant varieties.

It is appropriate to remember that Wallace had previously (in an article in 1856) rejected the evidence of examples of evolution drawn from the sphere of variability of domesticated animals, rightly pointing out that adaptive variability does not exist in domestic animals. After all, it is man who selects the best forms for him, and the animals themselves do not participate in the struggle for existence: “Thus, from observations of the varieties of domestic animals, no conclusions can be drawn regarding the varieties of animals living in the wild.”

Darwin's attitude towards Lamarck

Darwin never tired of repeating that his views had nothing in common with Lamarck’s, and throughout his life he never ceased to speak ill of his great predecessor. Perhaps the very thought that he was not the first and that 50 years before him the same thoughts had already been expressed by a Frenchman weighed heavily on him.

In the 1840s. in letters to Hooker, he wrote about this more than once: “... I don’t know any systematic works on this subject, except Lamarck’s book, but this is real rubbish”; “Lamarck... damaged the issue with his absurd, although intelligent, work”; “May Heaven save me from the stupid Lamarckian “striving for progress”, “adaptation due to the slow desire of animals” and so on.” True, he was forced to continue the last phrase from the above quotes with the words: “But the conclusions I come to do not differ significantly from his conclusions, although the methods of change are quite different.”

In one of his letters to Lyell, sent almost twenty years later, he wrote, discussing the significance of his predecessor’s work: “I look at it (the Philosophy of Zoology - author’s note), having read it carefully twice, as a miserable book , from which I gained no benefit. But I know you took advantage of her more.”

In general, as the Russian researcher of Darwinism Vl. Karpov, initially “Lamarck was alien and little understood by Darwin, as a representative of a different mentality, a circle of ideas, a different nationality.” Nevertheless, there were more fundamental similarities in the books of Lamarck and Darwin than differences. Both authors were unanimous on the central issue - the proclamation of the principle of progressive development of species, and both stated that it was the need to better meet the requirements of the external environment that forced species to progress.

Even the main groups of examples used by Darwin coincided with Lamarck's examples (breeds of dogs, poultry, garden plants). Only Darwin tried to give as many examples as possible, albeit of the same type, but giving the reader the impression of solidity and thoroughness; Lamarck limited himself to one or two examples for each point.

The extinction of species, according to Darwin, is a phenomenon that correlates with the origin of new species: “Since, over time, new species are formed by the activity of natural selection, others must become increasingly rare and finally disappear. ...In the chapter devoted to the struggle for existence, we saw that the most fierce competition should occur between forms that are closest - varieties of the same species or one genus or genera closest to each other, since these forms will have almost the same structure, a common warehouse and habits"

Where Darwin's thoughts differed greatly from Lamarck's was in his attempt to explain the causes of evolution. Lamarck looked for them inside organisms, in their inherent ability to change the structure of the body depending on the exercise of the organs (and in the second half of the 19th century, this position of Lamarck was regarded as extremely important, because the overwhelming majority of scientists believed that living beings inherently have the property of self-improvement). Darwin initially proceeded from the fact that the properties of organisms could change due to random reasons, and the external environment played the role of a controller, cutting off less adapted individuals. But since Darwin did not understand what could change in organisms, what hereditary structures were, these thoughts of his were entirely hypothetical philosophizing.

The paradox is that, having started with a categorical denial of Lamarck’s “stupid” views, Darwin gradually began to change his views and talk about the possibility of direct inheritance of characteristics acquired during life. The main reason for this change was the most important circumstance that also hindered Lamarck, namely: the lack of information about the laws of inheritance of traits, ignorance of the fact that there are special structures in the body that carry hereditary information.

However, if at the time of Lamarck science was still far from posing questions related to the discovery of the laws of heredity, and it would have been absurd to cast even a shadow of reproach against Lamarck, then by the time of the publication of “The Origin of Species” the situation had changed radically.

Gemmules instead of genes

The first approaches to understanding the laws of heredity, although still in a rather amorphous form, emerged as a result of the work of the German researcher Joseph Gottlieb Kölreuther (1733–1806), who worked for several years in St. Petersburg, and a number of other European scientists. Koelreuter in 1756–1760 conducted the first experiments on hybridization and formulated the concept of heritability.

The Englishman Thomas Andrew Knight (1789–1835), crossing different varieties of cultivated plants, came to the conclusion that in generations of hybrid plants, the characteristics by which the original varieties differ from each other “scatter” and appear individually. Moreover, he noted that there are minor individual differences that are not further “divided” during crossings and retain their individuality over generations. Thus, already at the beginning of the 19th century. Knight formulated the concept of elementary inherited traits.

Frenchman Auguste Sajray (1763–1851) in 1825–1835 made another important discovery. By monitoring Knight's "elementary traits," he discovered that some of them, when combined with others, suppressed the expression of those traits. This is how dominant and recessive traits were discovered.

In 1852, another Frenchman, Charles Naudin (1815–1899), studied these two types of traits more closely and, like Sajray, found that in combinations of dominant and recessive traits, the latter cease to appear. However, as soon as such hybrids are crossed with each other, they appear again in some of their descendants (later Mendel will call this process the splitting of characters). These works proved the most important fact - the preservation of hereditary structures that carry information about suppressed (recessive) traits, even in cases where these traits did not appear externally. Naudin tried to discover quantitative patterns of the combination of dominant and recessive traits, but, having undertaken to monitor a large number of them at once, he became confused in the results and was unable to move forward.

Darwin was well aware of the results of the work of these scientists, but he did not understand their significance, did not appreciate the great benefit that the discoveries of elementary hereditary units, the patterns of their combination and manifestation in descendants brought him. One more step should have been taken - to simplify the problem and analyze the quantitative distribution of traits in organisms that differ in one or at most two traits, and then the laws of genetics would have been discovered.

This breakthrough in science was made by the Czech naturalist and brilliant experimenter Johann Gregor Mendel, who in 1865 published a brilliant work in which he outlined the conclusions of experiments to identify the laws of heredity. Mendel built the scheme of his experiments precisely by simplifying the problem, when he decided to scrupulously monitor the behavior in crossings, first of only one inherited trait, and then of two. As a result, he proved, now definitively, the presence of elementary units of heredity, clearly described the rules of dominance, discovered quantitative patterns of combining units of heredity in hybrids and the rules for the splitting of hereditary characters.

Darwin, therefore, could have discovered these laws himself (he advanced in understanding the importance of elucidating the laws of inheritance, moreover, the progress of science at that time was so noticeable that what Mendel did was, in principle, accessible to anyone thinking about the problems of inheritance). But Darwin was not an experimenter. Of course, he could have simply read the work published by Mendel in German, but this also did not happen.

Instead, Darwin began to come up with a hypothesis (he pretentiously called it a theory) of pangenesis, about how the transmission of hereditary properties to descendants is carried out. He admitted the presence in any part of the body of “... special, independently reproducing and feeding hereditary grains - gemmules, which are collected in sexual products, but can be scattered throughout the body... each of which can restore in the next generation that part that gave them a start."

This hypothesis was by no means original: the same idea was put forward in his 36-volume History of Nature by Georges Louis Leclerc Buffon a hundred years before Darwin. Many major scientists, including those who helped Darwin strengthen his priority in proclaiming the role of natural selection in evolution (Hooker and Lyell), advised Darwin not to publish his “theory of pangenesis.” He verbally agreed with them, but in fact decided not to deviate from his own and included the corresponding chapter in the book “Changes in Animals and Plants under the Influence of Domestication,” published in 1868 (three years after Mendel’s work).

Until the end of his life, Darwin remained convinced that his theory of pangenesis was destined for a great future. Although in letters to those on whose help he depended all his life (Lyell, Hooker, Huxley), he coquettishly called this brainchild of his “a rash and half-baked hypothesis,” said that “to engage in such speculation is “pure nonsense”” and promised “ try to convince himself not to publish" a statement of his "theory", but he was not going to fulfill this promise, but only tried to dampen the critical fervor of his high friends. To other addressees at the same time he wrote something completely different: "Deep in my soul I believe that it contains a great truth" (letter to A. Gray, 1867), or: "I would rather die than cease to protect my poor child from attacks" (letter to G. Spencer, 1868). The same notes sounded later. : “With regard to pangenesis, I am not going to fold my banner” (letter to A. Wallace, 1875); “I had to think a lot about this issue, and I am convinced of its great significance, although it will take years until physiologists figure out that sexual organs only collect reproductive elements” (letter to J. Romains, 1875).

A tailless cat cannot be obtained by exercise.

In most cases, when discussing Darwin's pangenesis hypothesis, it is customary to say that its author did not go far from his time, but, they say, Mendel was ahead of his time by 35 years (it is not for nothing that his laws were actually rediscovered 35 years later). But we can say it another way: in understanding the mechanisms of inheritance of traits, Darwin did not reach the level of his contemporary Mendel.

Meanwhile, this question was the most important for Darwin. In the first edition of The Origin of Species, he proceeded from the premise that changes in living beings occur frequently and that they are indefinite: some are of some benefit to the organism, others are harmful or useless. He believed that with regard to useful traits, everything is clear - they are mainly inherited. “Any change, no matter how insignificant, and no matter what reasons it depends on, if it is in any way beneficial for an individual of any species, any such change will contribute to the preservation of the individual and will mostly be passed on to the offspring,” he wrote .

He believed that variability itself does not contain predetermination, original benefit. At this point he saw a radical difference between his views and Lamarck’s. There is no “internal striving for perfection”, no quality of predestination inherent in living beings in “improvement due to slow desire” (the words “slow desire” belonged to Darwin himself).

However, despite the demonstrative rejection of the Lamarckian postulate, Darwin, as the above quote shows about the inheritance of “any change, no matter how insignificant, and no matter what reasons it depends on,” as long as it “was beneficial for an individual of some kind.” species,” was even at this initial moment not too far from Lamarck. He also attributed to organisms an inherent (that is, predetermined) ability to retain, in a hereditary manner, any useful deviations. The hypothesis about gemmules perceiving useful stimuli did not change the essence of the matter. Darwin did not have a single fact in favor of his hypothesis, and in this sense, Lamarck with his “organ exercise” was no weaker in argumentation than Darwin.

Having rejected the Lamarckian inheritance of acquired characteristics, Darwin did not offer anything real in return, but simply bypassed the question of what, how and when is inherited, dividing possible variability into two types. The first is definitely favorable changes that the organism “craves” and which are the result of a direct response to the action of the environment (he denied such inheritance). The second type is uncertain changes that may not occur under the direct influence of the external environment (they are inherited). At this point, he saw the main difference between his doctrine and the views of Lamarck, which he considered erroneous.

But why are the first changes not inherited, while the second ones arise and are inherited? He had no idea what hereditary structures were and how they were passed on to descendants. By calling them gemmules, he did not come one iota closer to understanding their nature. Intuitively, he may have guessed that no matter how much you cut off the tails of cats so that when they jump from chests of drawers they do not knock down Wedgwood figurines, the offspring of tailless cats will still have tails.

"Jenkin's Nightmare"

The only belief that Darwin shared with most of his contemporaries was that the transmission of heredity is akin to the fusion of a fluid, say blood. The blood of the record-breaking mother merges with the blood of an ordinary, unremarkable father - and the result is a half-breed. And if identical organisms (siblings) give birth to offspring, then the offspring will be of “pure blood” (they will later be called a pure “line”).

Darwin fully adhered to these views, which is why he was so devastatingly affected by the criticism expressed in June 1867 by the engineer Fleming Jenkin in the journal Northern British Review. Jenkin was a major expert in electricity and electrical networks; with his personal participation, cables were laid in Europe, South and North America; he is considered the father of the telegraph; all his life he was the closest friend of William Thomson, who later became Lord Kelvin. A year before the publication of his devastating article on the main principle used by Darwin to justify natural selection, Jenkin became a professor in the school of engineering at University College London. With his brilliantly written article, containing not a single superfluous word, Jenkin was considered to have at one blow cut down Darwin's explanation of the inheritance of beneficial biases.

Let's say Darwin is right, Jenkin explained, and there is an indefinite variability, thanks to which some single organism has acquired a deviation that is useful for it (necessarily a single one, otherwise it is a massive Lamarckian change under the influence of the environment). But this lucky one will interbreed with an ordinary individual. This means that the “blood” will be diluted - the trait in the offspring will retain only half of the useful evasion. In the next generation, a quarter will remain of him, then an eighth, etc. As a result, instead of evolution, useful deviations will dissolve (Jenkin used the term swamping“swamping” or absorption of altered potency by unchanged hereditary potencies).

The criticism of the engineering professor caused Darwin to experience what he called “Jenkin’s nightmare.” As Darwin admitted in one of his letters, the correctness of his opponent’s reasoning “can hardly be questioned.” In a letter to Hooker dated August 7, 1860, Darwin wrote: “You know, I felt very humbled when I finished reading the article.”

In the end, after much thought, he saw only one way to respond to criticism: to admit that the environment directly influences heredity and thereby leads to changes in a large number of individuals living in new conditions. Only in this case, “resorption” of new signs should not have occurred. Such recognition of the role of the massive direct influence of the environment in progressive evolution meant a decisive convergence with Lamarck’s position and recognition of the principle of inheritance of acquired characteristics.

Agreeing with the arguments contained in Jenkin’s devastating article regarding Darwin’s mechanism of inheritance of useful traits, Darwin decided to make corrections to the next, fifth, and then sixth edition of the book. “...I am so sad,” he wrote to Hooker, “but my work is leading me to a somewhat greater recognition of the direct influence of physical conditions. Perhaps I regret it because it diminishes the glory of natural selection.”

Meanwhile, a way out for Darwin already existed. Gregor Mendel had proven several years earlier that hereditary structures do not merge with anything, but retain their structure unchanged. If the unit responsible for the transmission of heredity (later called the genome) is changed, and as a result the trait it controls is formed in a new way, then all the descendants of this first hereditarily changed organism will carry the same new trait. “Jenkin's Nightmare,” which had spoiled so much of Darwin's blood, was completely dissipating, and evolutionary theory was taking on a complete form. But Darwin did not know Mendel’s work, and he himself did not think of his conclusions.

Literature:
1) Loren C. Eisley. Charles Darwin, Edward Blyth, and the theory of natural selection // Proc. Amer. Philosopher Soc. 1959. V. 03, N. 1. P. 94–115.
2) Edward Blyth. An attempt to classify the “varieties” of animals, with observations on the marked seasonal and other changes which naturally take place in various British species, and which do not constitute varieties // (London). 1835. V. 8. P. 40–53; On the physiological distinction between man and all other animals, etc. // The Magazine of Natural History(London), n.s.. 1837. V. 1. P. 1–9, and P. 77–85, and P. 131–141; excerpts from Blyth's works, as well as Arthur Grout's memoirs of him, published in the August issue of the magazine Journ. of Asiatic Society of Bengal, 1875, are given as an appendix to Eisley’s article (see note /1/, pp. 115–160).
3) Wallace A.R. Darwinism. A presentation of the theory of natural selection and some of its applications. Translation from English prof. M. A. Menzbir. Library for self-education. M.: Publishing house. Sytin, 1898. T. XV.
4) Fleeming Jenkin. Review of The Origin of Species // North British Review. 1867. V. 46. P. 277–318.

See “Science at First Hand”, 2010, No. 3 (33). pp. 88–103.
“Science at first hand”, 2005, No. 3 (6). pp. 106–119.
Née Wedgwood, daughter of the owner of the famous ceramics factory (called "Wedgwood" to this day). She was famous for many virtues, including being a good pianist and taking music lessons from Chopin himself.
The most prominent American Darwinists of the 20th century. E. Mair, S. Darlington, S. D. Gould later disputed the opinion regarding Darwin's borrowing of E. Blyth's ideas, based on the fact that Blyth talked about the selection of degraded forms, and not about progressive evolution.
Already in the 20th century. Wallace's “law” on the role of geographic isolation in accelerating the evolution of species became an integral part of the doctrine called the “Synthetic Theory of Evolution,” developed by the American scientist of Russian origin F. G. Dobzhansky. S. S. Chetverikov was the first to point out the role of geographic isolation for gene selection in 1926 in his work “On some aspects of the evolutionary process from the point of view of modern genetics.”