The construction of the most fundamental evolutionary concept is associated with the name of the brilliant English scientist Charles Darwin (1809–1882). What he accomplished in 1831–1836 was of great importance for the development of Charles Darwin’s evolutionary and atheistic views. circumnavigation of the world on the Beagle. He studied the geological structure, flora and fauna of many countries, and sent a huge number of collections from England. Having compared the found remains of plants and animals with modern ones, Charles Darwin made an assumption about the historical, evolutionary relationship. On the Galapagos Islands, he found species of lizards, turtles, and birds that were not found anywhere else. The Galapagos Islands are islands of volcanic origin, so Charles Darwin suggested that these animals came to them from the mainland and gradually changed. In Australia, he became interested in marsupials and oviparous animals, which became extinct in other parts of the globe. So gradually the scientist’s conviction in . After returning from his trip, Darwin worked hard for 20 years to create the doctrine of evolution and collected additional facts about the development of new breeds of animals and plant varieties in agriculture. he considered it as a unique model of natural selection. His works “The Origin of Species by Natural Selection or the Preservation of Favored Breeds in the Struggle for Life”, “Change in Domestic Animals and Cultivated Plants”, “The Origin of Man and Sexual Selection” were published.
The main merit of Charles Darwin is that he revealed the mechanisms of formation and formation of species, that is, he explained the mechanism of evolution. He made his conclusions on the basis of a large amount of data accumulated by this time in the field of natural science, animal husbandry and crop production. The first possible conclusion drawn by Darwin was the conclusion that it exists in nature. This conclusion was made on the basis of the fact that out of a huge number of individuals born, only a few survive to adulthood, therefore, according to Darwin, the rest die in the struggle for life. The second conclusion was the conclusion that for organisms of character there is universal variability in characteristics and properties (even in the offspring of one pair of parents there are no identical individuals). Under fairly stable conditions, these small differences may not matter. However, with sudden changes in living conditions, one or more distinctive features may become decisive for survival. Having compared the facts of the struggle for the existence of the universal variability of organisms, Darwin makes a generalized conclusion about the existence of “natural selection” in nature (the selective survival of some individuals and the death of other individuals). The material for natural selection is supplied by the variability of organisms (mutational and combinative). The results of natural selection is the formation of a large number of adaptations to specific living conditions, which we consider from a taxometric point of view - we combine them into similar organisms into species, genera, and families.
The main provisions of the evolutionary teachings of Charles Darwin boil down to the following:
The diversity of animal and plant species is the result of the historical development of the organic world.
The main driving forces of evolution are the struggle for existence and natural selection. The material for natural selection is provided by hereditary variability. The stability of the species is ensured by heredity.
The organic world mainly followed the path of complicating the organization of living beings.
is the result of natural selection.
Both favorable and unfavorable changes can be inherited.
The variety of modern breeds of domestic animals and varieties of agricultural plants is the result of action.
associated with the historical development of ancient apes.
Charles Darwin's teaching can be considered as a revolution in the field of natural science. The significance of evolutionary theory is as follows:
The patterns of transformation of one organic form into another have been revealed.
The reasons for the expediency of organic forms are explained.
The law of natural selection was discovered.
The essence of artificial selection has been clarified.
The driving forces of evolution have been identified.
Darwin's evolutionary theory is a holistic doctrine of the historical development of the organic world. It covers a wide range of problems, the most important of which are evidence of evolution, identifying the driving forces of evolution, determining the paths and patterns of the evolutionary process, etc.
The essence of evolutionary teaching lies in the following basic principles:
1. All types of living beings inhabiting the Earth were never created by anyone.
2. Having arisen naturally, organic forms were slowly and gradually transformed and improved in accordance with environmental conditions.
3. The transformation of species in nature is based on such properties of organisms as variability and heredity, as well as natural selection constantly occurring in nature. Natural selection occurs through the complex interaction of organisms with each other and with factors of inanimate nature; Darwin called this relationship the struggle for existence.
4. The result of evolution is the adaptability of organisms to their living conditions and the diversity of species in nature.
4. Prerequisites and driving forces of evolution according to Darwin
In Darwin's evolutionary theory, the prerequisite for evolution is hereditary variability, and the driving forces of evolution are the struggle for existence and natural selection. When creating an evolutionary theory, Charles Darwin repeatedly turned to the results of breeding practice. He tries to find out the origin of breeds of domestic animals and varieties of plants, to reveal the reasons for the diversity of breeds and varieties and to identify the methods by which they were obtained. Darwin proceeded from the fact that cultivated plants and domestic animals are similar in a number of characteristics to certain wild species, and this cannot be explained from the perspective of the theory of creation. This led to the hypothesis that cultivated forms originated from wild species. On the other hand, plants and domesticated animals introduced into culture did not remain unchanged: man not only chose the species of interest to him from the wild flora and fauna, but also significantly changed them in the right direction, creating a large number of plant varieties and breeds from a few wild species animals. Darwin showed that the basis for the diversity of varieties and breeds is variability - the process of the emergence of differences in descendants in comparison with ancestors, which determine the diversity of individuals within a variety or breed. Darwin believes that the causes of variability are the impact of environmental factors on organisms (direct and indirect, through the “reproductive system”), as well as the nature of the organisms themselves (since each of them specifically reacts to the influence of the external environment). Having determined his attitude to the question of the causes of variability, Darwin analyzes the forms of variability and distinguishes among them three: definite, indefinite and correlative.
Specific, or group, variability is variability that occurs under the influence of some environmental factor that acts equally on all individuals of a variety or breed and changes in a certain direction. Examples of such variability include an increase in body weight in all animal species with good feeding, changes in hair coat under the influence of climate, etc. A certain variability is widespread, covers the entire generation and is expressed in each individual in a similar way. It is not hereditary, i.e. in the descendants of the modified group, when placed in other environmental conditions, the characteristics acquired by the parents are not inherited.
Uncertain, or individual, variability manifests itself specifically in each individual, that is, it is single, individual in nature. With indefinite variability, various differences appear in individuals of the same variety or breed, by which, under similar conditions, one individual differs from others. This form of variability is uncertain, i.e. a trait under the same conditions can change in different directions. For example, one variety of plants produces specimens with different colors of flowers, different intensities of color of petals, etc. The reason for this phenomenon was unknown to Darwin. Uncertain, or individual, variability is hereditary in nature, i.e. is persistently transmitted to offspring. This is its importance for evolution.
With correlative or relative variability, a change in any one organ causes changes in other organs. For example, dogs with poorly developed coats usually have underdeveloped teeth, pigeons with feathered feet have webbed toes, pigeons with a long beak usually have long legs, white cats with blue eyes are usually deaf, etc. From the factors of correlative variability, Darwin draws an important conclusion: a person, selecting any structural feature, is almost “likely to unintentionally change other parts of the organism on the basis of mysterious laws of correlation.”
Having determined the form of variability, Darwin comes to the conclusion that only heritable changes are important for the evolutionary process, since only they can accumulate from generation to generation. According to Darwin, the main factors in the evolution of cultural forms are hereditary variability and selection made by humans (Darwin called such selection artificial).
What are the driving forces behind the evolution of species in nature? Darwin considered the explanation of the historical variability of species possible only through revealing the reasons for adaptability to certain conditions. Darwin came to the conclusion that the fitness of natural species, as well as cultural forms, is the result of selection, but it was not produced by man, but by environmental conditions.
Among the factors limiting the number of species (this means causing a struggle for existence), Darwin includes the amount of food, the presence of predators, various diseases and unfavorable climatic conditions. These factors can influence species abundance directly and indirectly through complex relationships. Mutual contradictions between organisms play a very important role in limiting the number of species. For example, sprouted seeds most often die because they sprouted on soil that is already densely overgrown with other plants. These contradictions become especially acute in cases where the issue concerns the relationships between organisms that have similar needs and a similar organization. Therefore, the struggle for existence between species of the same genus is more severe than between species of different genera. Even more intense are the contradictions between individuals of the same species (intraspecific struggle).
The natural result of contradictions between organisms and the external environment is the extermination of some individuals of the species. If some individuals of each species die in the struggle for existence, then the rest are able to overcome unfavorable conditions.
Selection occurs continuously over an endless series of successive generations and preserves mainly those forms that are more consistent with given conditions. Natural selection and elimination of part of a particular species are inextricably linked and are a necessary condition for the evolution of species in nature.
The scheme of action of natural selection in a species system, according to Darwin, boils down to the following:
1. Variation is common to every group of animals and plants, and organisms differ from each other in many different ways.
2. The number of organisms of each species that are born is greater than the number that can find food and survive. However, since the number of each species is constant under natural conditions, it should be assumed that most of the offspring die. If all the descendants of a species survived and reproduced, they would soon replace all other species on the globe.
3. Since more individuals are born than can survive, there is a struggle for existence, competition for food and habitat. This may be an active life-and-death struggle or a less obvious one; but no less effective competition, as, for example, when plants experience drought or cold.
4. Among the many changes observed in living beings, some facilitate survival in the struggle for existence, while others lead to the death of their owners. The concept of "survival of the fittest" is the core of the theory of natural selection.
5. Surviving individuals give rise to the next generation, and thus “successful” changes are passed on to subsequent generations. As a result, each subsequent generation turns out to be more and more adapted to the environment; as the environment changes, further adaptations arise. If natural selection operates over many years, then the latest offspring may turn out to be so different from their ancestors that they can be separated into an independent species.
It may also happen that some members of a given group of individuals will acquire certain changes and find themselves adapted to the environment in one way, while other members, possessing a different set of changes, will be adapted in a different way; In this way, from one ancestral species, subject to the isolation of similar groups, two or more species can arise.
Introduction…………………………………………………………………………………….……..3
I. The history of the creation of Charles Darwin’s evolutionary theory………………….….……4
II. Basic provisions of evolutionary teaching………………………………...6
III. Variability……………………………………………………….………..8
IV. Artificial selection..............................................................................................10
V. Natural selection…………………………………………..………………….13
1. Driving selection…………………………...………………...………………15
2. Stabilizing selection……………………………………………17
3. Disruptive selection…………………………….…………...………19
4. Sexual selection………………………………………….……………….…20
5. The struggle for existence……………………………….…………...….22
VI. The significance of Darwin's theory of evolution…………………..………………25
Conclusion. …………………………………………………….………...…..26
References………………………………………………………...28
Introduction.
In this essay, I examined Charles Darwin’s theory of evolution, which occupies a special position in biology. In terms of its significance in the development of biology and science in general, it stands above many past and present evolutionary constructs. It is not a comprehensive evolutionary theory and solves only part of the problems of the theory of evolution. Nevertheless, Darwin's constructions, of course, belong to the outstanding achievements of the human mind and occupy a leading place in the theoretical biology of the past and present.
The theory of evolution played a revolutionary role in biology, determining the direction of its development for many years. At the same time, the complex and largely speculative nature of Darwin's theoretical constructions caused numerous disputes, disagreements and misunderstanding among his contemporaries. The lack of factual data that could confirm or refute the correctness of Darwin's evolutionary views forced biologists to begin a rigorous scientific study of individual provisions of the theory of speciation. A long period of development of Darwinian theory began, which continues to this day.
This theory has always created a lot of controversy around itself, there is its
followers and opponents, which means it is worthy of attention, which is why my work is dedicated to it.
I. The history of the creation of evolutionary theory.
The English scientist Charles Darwin made an invaluable contribution to biological science by creating a theory of the development of the animal world, based on the determining role of natural selection as the driving force of the evolutionary process. The foundation for the creation of the theory of evolution was his observations during a trip around the world on the Beagle. He began developing the theory of evolution in 1837, and only twenty years later, at a meeting of the Linnean Society in London, Darwin read a report containing the main provisions of the theory of natural selection.
The main work of the scientist’s entire life, named verbosely according to the tradition of that era: “The Origin of Species by Natural Selection or the Preservation of Favored Breeds in the Struggle for Life,” was published on November 24, 1859 and sold 1,250 copies, which at that time was considered for a scientific work unheard of. It should be noted that the first sketch of the theory of evolution was made by Darwin back in 1842.
In this work, Darwin showed that the species of plants and animals are not constant, but changeable, and that the species that exist today evolved naturally from other species that existed earlier. The expediency observed in living nature was created and is being created through natural selection of undirected changes beneficial to the body. Thus, in the struggle for existence, the forms most adapted to given environmental conditions survive.
In 1868, Darwin published his second major work -
“Change in Domestic Animals and Cultivated Plants,” which was a supplement to the main work. This work includes a lot of factual evidence of the evolution of organic forms, drawn from centuries-old human practice. Darwin published his third major work on the theory of evolution, “The Descent of Man and Sexual Selection,” in 1871, and was supplemented by the book “The Expression of the Emotions in Man and Animals.”
It is the evolutionary theory that most clearly describes the process of speciation in living nature, and therefore it is advisable to focus on it.
I I . Basic provisions of the evolutionary process.
While traveling on the Beagle, after studying the geology of South America, Darwin became convinced of the inconsistency of the catastrophe theory and emphasized the importance of natural factors in the history of the earth's crust and its animal and plant populations. Thanks to paleontological finds, he notes the similarities between extinct and modern animals of South America. He finds so-called transitional forms that combine the characteristics of several orders. Thus, the fact of continuity between modern and extinct forms was established.
Darwin also names a number of connecting forms. In particular, South American
Macrauchenia combines two large divisions: pariodactyls and odd-toeds
ungulates; Hipparion is an intermediate form between
the modern horse and some ancient ungulates. South American
hypothermia is that amazing connecting link that cannot be
placed separately in any of the existing squads. Zeuglodon and
squalodon - connecting links between those living in the water and all others
geographical distribution of animals. The fauna of South America includes
forms not found in North America (monkeys, llamas, sloths, anteaters,
armadillos). However, in his opinion, the similarity of the faunas of both continents was
place in past geological eras. Subsequently, faunas became isolated
South and North America due to the appearance of a barrier (plateau) in the southern part of Mexico.
Darwin collected particularly interesting data on the Galapagos Islands,
lying 950 km from the West Coast of South America in the Pacific Ocean. These
the islands are of volcanic origin, young geologically, then
there arose later than the American continent. Studying the endemic species living there
forms of turtles, finches, etc., he noted that the fauna of this archipelago is similar
with the fauna of South America, but at the same time different from it.
Darwin shows the American origin of the Galapagos fauna. He
noted that each island of this archipelago has its own form of finches.
But they all form one natural group and originate from one
the original species that lived on the nearby American continent.
So, at the beginning of the 19th century, based on extensive factual material, there were
some important generalizations were made: about the variability of species, about natural
groups of organisms, the unity of the structural plan of organisms, the change of forms and
increase in successive geological horizons of similarity in structure
extinct forms with modern ones, about the historical development of the earth’s crust, as well as
about the similarity of embryos of systematically distant groups of animals.
Thus, the doctrine of the evolution of the organic world is the largest
generalization of natural science of the 19th century - was prepared as by the previous
the development of scientific thought and socio-economic conditions.
In Darwin's evolutionary theory, problems such as:
The problem of transforming one organic form into another.
The problem of the purposiveness of organic beings
The problem of driving forces and factors of evolution.
Darwin's theory of evolution was one of the first successful examples
solving important problems in the development of wildlife from the perspective
natural historical materialism. She had a huge impact on everything
biological sciences, establishing an understanding of living nature and giving
materialistic explanation of the phenomena of expediency.
The positive side of Darwin's theory is its close connection with
selection practice, which served as the basis for the construction
evolutionary theory. To analyze the process of evolution of the organic world
Darwin not only used these practices, but also critically revised his
conclusions taking into account advances in biology and agriculture. This answered
the generally accepted principle that practice is the main thing
criterion of truth, and led to a radical restructuring of the biological sciences and
solving many general biological problems.
III . Variability.
The starting point of Darwin's teaching is his assertion that there is
variability in nature.
Variability is the general property of organisms to acquire new characteristics of differences between individuals within a species.
It can be clearly seen in comparisons of many animal breeds and
varieties of plants bred by humans in different places around the world. So, in
There are 38 varieties of date palms in North Africa. Only on one
the island of Polynesia cultivates 24 forms of breadfruit and the same number of forms
bananas There are 63 varieties of bamboo grown in China. Within any animal species
and plants, and in culture - within any variety and breed there are no identical
Many gardeners recognize hyacinth and tulip varieties by their bulbs. This means that all animals and plants are different from their own kind, although to the untrained eye they seem the same. Based on these facts, Darwin concludes that animals and plants are inherent in variability.
The idea of gradual and continuous change in all species of plants and animals was expressed by many scientists long before Darwin. Therefore the very concept evolution - the process of long-term, gradual, slow changes, which ultimately lead to fundamental, qualitative changes - the emergence of new organisms, structures, forms and species, penetrated into science at the end of the 18th century.
However, it was Darwin who put forward a completely new hypothesis regarding living nature, generalizing individual evolutionary ideas into one, the so-called theory of evolution, which has become widespread in the world.
During his trip around the world, Charles Darwin collected a wealth of material indicating the variability of plant and animal species. A particularly striking find was a huge fossil sloth skeleton discovered in South America. Comparison with modern, small sloths prompted Darwin to think about the evolution of species.
The richest empirical material accumulated by that time in geography, archeology, paleontology, physiology, taxonomy, etc., allowed Darwin to draw a conclusion about the long-term evolution of living nature. Darwin outlined his concept in his work "The Origin of Species by Natural Selection""(1859). Charles Darwin's book was a phenomenal success; its first edition (1250 copies) was sold on the first day. The book was about explaining the emergence of living beings without appealing to the idea of God.
It should be noted that, despite its enormous popularity among the reading public, the idea of the gradual appearance of new species in wildlife turned out to be so unusual for the scientific community of that time that it was not immediately accepted.
Darwin suggested that there is competition in animal populations, due to which only those individuals survive that have properties that are advantageous in given specific conditions, allowing them to leave offspring. The basis of Darwin's evolutionary theory is made up of three principles: a) heredity and variability; b) struggle for existence; c) natural selection. Variability is an integral property of all living things. Despite the similarity of living organisms of the same species, it is impossible to find two completely identical individuals within a population. This variation in characteristics and properties creates an advantage for some organisms over others.
Under normal conditions, the difference in properties remains unnoticeable and does not have a significant impact on the development of organisms, but when conditions change, especially in an unfavorable direction, even the slightest difference can give some organisms a significant advantage over others. Only individuals with properties appropriate to the conditions are able to survive and leave offspring. Darwin distinguishes between indefinite and definite variability.
Certain variability, or adaptive modification,- the ability of individuals of the same species to respond in the same way to changes in the environment. Such group changes are not inherited, and therefore cannot supply material for evolution.
Uncertain variability, or mutation, - individual changes in the body that are inherited. Mutations are not directly related to changes in environmental conditions, but it is uncertain variability that plays a critical role in the evolutionary process. Positive changes that occur by chance are inherited. As a result, only a small part of the offspring, possessing useful hereditary properties, survives and reaches maturity.
Between living beings, according to Darwin, a struggle for existence unfolds. Concretizing this concept, Darwin pointed out that within a species more individuals are born than survive to adulthood.
Natural selection- a leading factor in evolution that explains the mechanism of formation of new species. It is this selection that acts as the driving force of evolution. The selection mechanism leads to the selective destruction of those individuals that are less adapted to environmental conditions.
Criticism of the concept of Darwinian evolution
Neo-Lamarckism was the first major anti-Darwinian doctrine that appeared at the end of the 19th century. Neo-Lamarckism was based on the recognition of adequate variability that arises under the direct or indirect influence of environmental factors, forcing organisms to directly adapt to them. Neo-Lamarckists also spoke about the impossibility of inheriting traits acquired in this way and denied the creative role of natural selection. The basis of this doctrine was the old ideas of Lamarck.
Among other anti-Darwinian teachings, we note theory of nomogenesisL. C. Berg, created in 1922. This theory is based on the idea that evolution is a programmed process of implementing internal laws inherent in all living things. He believed that organisms are endowed with an internal force of an unknown nature that acts purposefully, regardless of the external environment, in the direction of increasing the complexity of the organization. To prove this, Berg cited a lot of data on the convergent and parallel evolution of different groups of plants and animals.
Charles Darwin believed that natural selection ensures progress in the development of living organisms. In addition, he emphasized that the elementary unit of evolution is not the individual, but the species. However, it was later established that the elementary unit of evolution is not kind, A population.
The weak link of Charles Darwin's evolutionary theory was the lack of an accurate and convincing mechanism of heredity. Thus, the evolutionary hypothesis did not explain how the accumulation and preservation of beneficial hereditary changes occurs as a result of further crossing of living organisms. Contrary to the popular belief that when crossing organisms with useful properties and organisms that do not have these properties, there should be an averaging of useful characteristics, their dissolution in a series of generations. The evolutionary concept assumed that these traits accumulated.
C. Darwin was aware of the weakness of his concept, but was unable to satisfactorily explain the mechanism of inheritance.
The answer to this question was given by the theory of the Austrian biologist and geneticist Mendel, which substantiated the discrete nature of heredity.
Created in the 20th century. synthetic theory of evolution(STE) completed the integration of evolutionary theory with genetics. STE is a synthesis of Darwin's basic evolutionary ideas, and above all natural selection, with new research results in the field of heredity and variability. An important component of STE are the concepts of micro- and macroevolution. Under microevolution understand the totality of evolutionary processes occurring in populations, leading to changes in the gene pool of these populations and the formation of new species.
It is believed that microevolution occurs on the basis of mutational variability under the control of natural selection. Mutations are the only source of the emergence of qualitatively new characteristics, and natural selection is the only creative factor in microevolution.
The nature of microevolutionary processes is influenced by fluctuations in population numbers (“waves of life”), the exchange of genetic information between them, their isolation and genetic drift. Microevolution leads either to a change in the entire gene pool of a biological species as a whole, or to their separation from the parent species as new forms.
Macroevolution is understood as evolutionary transformations leading to the formation of taxa of a higher rank than the species (genera, orders, classes).
It is believed that macroevolution does not have specific mechanisms and is carried out only through the processes of microevolution, being their integrated expression. As they accumulate, microevolutionary processes are expressed externally in macroevolutionary phenomena, i.e. macroevolution is a generalized picture of evolutionary change. Therefore, at the level of macroevolution, general trends, directions and patterns of evolution of living nature are discovered that cannot be observed at the level of microevolution.
Some events that are usually cited as evidence for the evolutionary hypothesis can be reproduced in the laboratory, but this does not mean that they actually occurred in the past. They only indicate that these events could have happened.
Many objections to the evolutionary hypothesis are still unanswered.
In connection with criticism of Darwin's hypothesis of natural selection, it is advisable to note the following. Currently, having marked a civilizational crisis - a crisis of the basic ideological principles of humanity - it is becoming increasingly clear that Darwinism is just a particular model of competitive interaction that unjustifiably claims to be universal.
Let us take a closer look at the central link of Darwinism - the property of adaptability or adaptability of the evolutionary process. What does it mean - a more adapted individual or individuals? Strictly speaking, there is no answer to this question in Darwinism, and if there is an indirect answer, it is erroneous.
The indirect answer is as follows: the fittest individual will be the one that wins the competition and survives. The latter inevitably leads to the idea of a gangster individual and an aggressor species. Populations and ecosystems with such an aggressor species would be clearly unstable: they would not be able to exist for a long time. This contradicts the facts and ideas established in biology that sustainable ecosystems are generally in equilibrium, and replacement processes do not occur in them.
The way for sustainable existence of populations, communities and ecosystems is cooperation and mutual complementarity 115].
Competition is of a private nature: it is fully involved in a non-equilibrium population moving towards equilibrium, and plays the role of a kind of catalyst, accelerating the movement of the ecosystem towards equilibrium. However, directly related to evolution, i.e. progress, this kind of competition does not exist. Example: the introduction of a species into a new area - the importation of a rabbit to Australia. There was competition for food, but no new species, much less a progressive one, arose. Another example: a litter of rabbits was also released on the island of Porto Sonto in the Atlantic Ocean. Unlike their European counterparts, these rabbits have become smaller and have different colors. When crossed with a European species, they did not produce fertile offspring - a new species of rabbits emerged. It is clear that competition was also involved in the establishment of an equilibrium population. However, speciation occurred not at its expense, but due to new environmental conditions. At the same time, there is no evidence that the emerging species of rabbits is more progressive than the European one.
Thus, the purpose of competition is completely different from that in Darwin's hypothesis of natural selection. Competition eliminates abnormal, “decay” individuals (with disturbances in the genetic apparatus). Thus, competitive interaction eliminates regression. But the mechanism of progress is not competitive interaction, but the discovery and development of a new resource: as evolution proceeds, the smarter one gets an advantage.
Darwin's concept is constructed as a negative process in which not the strongest survive, but the weakest perish.
Darwinism denies trends—patterns that are quite obvious (for example, Georgians and Ukrainians sing well), arguing that all essential properties are determined by their usefulness for survival.
Darwinism is generally pointless, since natural selection simply does not exist in nature.
As is known, Darwin did not give examples of natural selection in nature, limiting himself to an analogy with artificial selection. But this analogy is unsuccessful. Artificial selection requires the forced crossing of desired individuals while completely excluding the reproduction of all others. There is no such selective procedure in nature. Darwin himself recognized this.
Natural selection does not represent selective crossing, but selective reproduction. In nature, only a few examples have been found of how, thanks to selective reproduction, the frequency of carriers of a certain trait changes, but that’s all. It was not possible to find a single example where something new appeared as a result of this procedure (except for that boring case when turning on or off already existing gene).
The only justification for Darwinism is still the analogy with artificial selection, but also it has not yet led to the emergence of at least one new genus, not to mention the family, detachment and above. Thus, Darwinism is not a description of evolution, but a way of interpreting a small part of it (changes within a species) using a hypothetical cause called natural selection.
Evolution not according to Darwin
The direction of evolution is determined by whose set of genes is introduced into the next generation, not by whose set of genes disappeared in the previous one.
The “modern” theory of evolution - the synthetic theory of evolution (STE), based on the synthesis of Darwin's theory of natural selection with Mendelian genetics, proves that the cause of variability is mutations - sudden changes in the hereditary structure of an organism that occur randomly, also doesn't solve the problem.
IN evolution is based not Darwinian selection, not mutations (as in STE), but individual intraspecific variability, which exists constantly in all populations. It is individual variability that provides the basis for the preservation of certain functions in the population. It’s as if aliens arrived and started beating us with a huge colander, into the holes of which the smartest (smartest) would slip. Then those who think worse would simply disappear.
Horizontal gene transfer has been known for many years, i.e. acquisition of hereditary information in addition to the process of reproduction. It turned out that in the chromosomes and cytoplasm of the cell there are a number of biochemical compounds that are in a chaotic state and are capable of interacting with the nucleic acid structures of another organism. These biochemical compounds were called plasmids. Plasmids are capable of being incorporated into a recipient cell and activated under the influence of certain external factors. The transition from a latent state to an active state means the combination of the donor's genetic material with the recipient's genetic material. If the resulting construct is functional, protein synthesis begins.
Based on this technology, insulin was synthesized - a protein that helps fight diabetes.
In unicellular microorganisms, horizontal gene transfer is decisive in evolution.
Migrating genetic elements show significant similarity to viruses. Discovery of the phenomenon of gene transduction, i.e. transfer of genetic information into plant and animal cells using viruses that include part of the genes of the original host cell, suggests that viruses and similar biochemical formations occupy a special place in evolution.
Some scientists express the opinion that migrating biochemical compounds can cause even more serious changes in cell genomes than mutations. If this assumption turns out to be correct, then it will be necessary to significantly revise current ideas about the mechanisms of evolution.
Hypotheses are now being put forward about the significant role of viruses in the mixing of genetic information of different populations, the occurrence of leaps in the evolutionary process, in a word, we are talking about the most important role of viruses in the evolutionary process.
Viruses are among the most dangerous mutagens. Viruses- the smallest of living creatures. They do not have a cellular structure and are not capable of synthesizing protein themselves, so they obtain the substances necessary for their life activity by penetrating a living cell and using foreign organic substances and energy.
In humans, as in plants and animals, viruses cause many diseases. Although mutations are the main suppliers of evolutionary material, they are random changes that obey probabilistic laws. Therefore, they cannot serve as a determining factor in the evolutionary process.
Nevertheless, the idea of the leading role of mutations in the evolutionary process formed the basis theory of neutral mutations, created in the 1970s and 1980s by Japanese scientists M. Kimura and T. Ota. According to this theory, changes in the functions of the protein-synthesizing apparatus are the result of random mutations that are neutral in their evolutionary consequences. Their true role is to provoke genetic drift - a change in the purity of genes in a population under the influence of completely random factors.
On this basis, the neutralist concept of non-Darwinian evolution was proclaimed, the essence of which lies in the idea that natural selection does not work at the molecular genetic level. And although these ideas are not generally accepted among biologists, it is obvious that the direct arena of natural selection is the phenotype, i.e. living organism, ontogenetic level of life organization.
Recently, another concept of non-Darwinian evolution has emerged - punctualism. Its supporters believe that the process of evolution proceeds through rare and rapid leaps, and 99% of its time the species remains in a stable state - stasis. In extreme cases, the leap to a new species can occur in a population of only a dozen individuals over the course of one or several generations.
This hypothesis rests on a broad genetic basis laid by a number of fundamental discoveries in molecular genetics and biochemistry. Punctualism rejected the genetic-population model of speciation, Darwin's idea of varieties and subspecies as emerging species, and focused its attention on the molecular genetics of the individual as the bearer of all the properties of the species.
The value of this concept lies in the idea of the disunity of micro- and macroevolution (as opposed to STE) and the independence of the factors controlled by them.
Thus, Darwin's concept is not the only one trying to explain the evolutionary process. However, Darwin was made into an icon, and Darwinism into a religion (the word “selection” is used colloquially, like bread and water). If a religion can only be superseded by another religion, then what religion can replace Darwinism today with benefit to people? Classical religions cannot do this because they profess creationism, and it contradicts science and therefore alienates precisely those on whom one should rely.
The religion of veneration of nature as a whole can supplant Darwinism, to the common benefit(where man is only a part of nature, a product of it). This is the only way to replace the ideology of “fight against nature” that the dominance of Darwinism asserts on planet Earth.
The seeds of reverence for nature as a whole are already visible in the emerging environmental movements.
The temporary establishment in the world of the Darwinian worldview, supplemented by economic market mechanisms, was one of the main ideological causes of the modern civilizational crisis.
You should also pay attention to the review of Darwinism made back in the 19th century. the leading pathologist R. von Virchow, at the congress of naturalists in Munich. He demanded that the study and dissemination of the ideas of Darwinism be prohibited, since its spread could lead to a repetition of the Paris Commune.
Perhaps in the future, STE and non-Darwinian concepts of evolution, complementing each other, will unite into a new single theory of life and development of living nature.
Doctor of Physical and Mathematical Sciences“Science at first hand” No. 4(34), 2010
About the authorDoctor of Physical and Mathematical Sciences, Honored Professor of the University. George Mason (USA), foreign member of the National Academy of Sciences of Ukraine, academician of the New York Academy of Sciences, honorary professor of the Siberian Branch of the Russian Academy of Sciences, Moscow State University. Lomonosov and Jerusalem University. In 1961–1970 worked at the institutes of the USSR Academy of Sciences and Academy of Medical Sciences, from 1970 to 1978 at the All-Russian Academy of Agricultural Sciences. In 1974 he created the All-Union Research Institute of Applied Molecular Biology and Genetics of the All-Union Academy of Agricultural Sciences in Moscow. Areas of scientific interest: the effect of radiation and chemicals on genes, the study of the physicochemical structure of DNA, repair in plants, the effect of radioactive contamination on the human genome. Awarded the International Gregor Mendel Medal and the N. I. Vavilov Silver Medal. Author of more than 20 books, including on the history of science, published in Russia, the USA, England, Germany, Vietnam and the Czech Republic, editor-in-chief of the 10-volume encyclopedia "Modern Natural Science", member of the editorial board of the magazine "SCIENCE First Hand" |
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 FitzRoy. 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 prompted 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 repeated for decades did 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 on June 5, 1844, a long letter to his wife Emma, 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 the 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, 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 the most 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, rather than 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 favorably to Wallace's work, and from that time on a 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 the principle of the struggle for existence, or about 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 better 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 will 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 small 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 did not intend to fulfill this promise, but only tried to dampen the critical fervor of his high friends. At the same time, he wrote to other addressees something completely different: “In the depths of my soul, I believe that. there is a great truth in it” (letter to A. Gray, 1867), or: “I would rather die than stop protecting my poor child from attacks” (letter to G. Spencer, 1868). : “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 what the sexes are.” 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 inherent quality of predestination 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 quotation shows about the inheritance of “any change, no matter how insignificant, and no matter what causes it depends,” 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, undistinguished 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 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 the reason I regret it is that 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.”
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