| SIGNS | Evolutionary theory of C. LINNEAUS (metaphysician: nature was created by God and is unchangeable) | Evolutionary theory of J.-B. LAMARC
| Evolutionary theory CH. DARWIN 1809-1882
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| Creating a theory | In the 18th century C. Linnaeus created an artificial system of nature in whichthe species was recognized as the smallest systematic unit . He enterednomenclature of double species names (binary) in Latin, which made it possible to systematize the organisms of different kingdoms known at that time into taxonomic groups. In 1751, his book “Philosophy of Botany” was published, where he outlined the binomial (binary) nomenclature he developed. Scientistdivided all living organisms known to him into groups, based on anatomical, morphological and partly physiological criteria(work “System of Nature”, described 10 thousand species of plants and 4.5 thousand living species); in other words, his classification was artificial. Therefore, in this system, systematically distant organisms sometimes ended up in the same class, and related ones - in different ones. K. Linnaeusfor the first time placed humans and apes in the same order, but did not believe that man descended from monkeys.The species was identified and recognized as a truly existing unit of taxonomy. He realized the shortcomings of his system. | In 1794 - the term “Zoology of invertebrates” (basics of taxonomy of invertebrates), 1802 - “Biology”. In 1809 he proposedthe first holistic theory of evolution (the book “Philosophy of Zoology”), was appreciated only 50 years later. Analyzed and listed the similarities and differences between living and nonliving matter. Main point:matter and the laws of its development were created by the creator . The first factor of evolution – gradation internal “striving for improvement.” How and why this desire arose, Lamarck did not explain and did not even consider this question worthy of attention. The result of gradation is the simultaneous existence in nature of organisms of different levels of complexity.Second factor of evolution – The constant influence of the external environment determines the formation of the entire variety of adaptations of living beings.The third factor of evolution – heredity. Evolution according to Lamarck was presented as a continuous progressive movement from lower forms of life to higher ones (the ladder of beings). To explain the varying degrees of structural complexity observed among modern species, he assumed the constant spontaneous generation of life: the ancestors of more highly organized forms arose earlier and therefore their descendants went further along the path of progress.2 laws: The law of exercise and non-exercise, The law of inheritance of acquired characteristics. | Proposed in 1859 by the English naturalist Charles Darwin The evolutionary teaching of Charles Darwin includes three large components: 1. Evidence in favor of the historical development of the organic world 2. Statement on the driving forces of evolution 3. Idea of the paths of evolutionary transformations. |
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| The emergence of life | K. Linnaeus shared metaphysical views on nature, seeing in it the original purposefulness and wisdom of the Creator. | Life arose and arises through repeated spontaneous generation from inanimate nature (polyphyly). | Life arose, from the very beginning, formed by the creator into one or more forms (monophyly) |
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| Starting point of evolution | Primordial expediency, the wisdom of the Creator. | Matter and the laws of its development created by the creator. Single-celled organisms are capable of spontaneous generation, and organisms with a higher organization appeared as a result of long-term development. | Innate individuality, variability |
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| The influence of the environment on the body | At the end of his life he recognized that species could arise through crossing or as a result of changes in the environment. | The environment, having caused a change in habits, causes a change in the functional activity of the body (reduction of organs). The functional activity of organs causes changes in their nutrition, as a result of which their size and shape change | The environment (for example, famine, etc.) causes mass death of organisms and the survival of the fittest. Natural selection occurs |
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| Variability | Species of plants and animals do not change; they have retained their characteristics since creation. When reproducing, they retain all the characteristics of the ancestral pair. Different species are not related. | Lamarck believed that changes arising under the influence of the environment can be inherited. He believed that intense exercise of organs leads to their enlargement, and lack of exercise leads to degeneration. So Lamarck explained the long nose of the anteater by the fact that from generation to generation his ancestors exercised their nose, sniffing in search of ants. He considered the reduction of eyes in moles to be a consequence of their lack of exercise over generations. Neither Lamarck nor his followers asked the question, why, in fact, intensive exercise, the use of an organ, should certainly lead to its improvement, improvement, and not, for example, to wear and tear, as machine parts wear out? | Natural selection, reinforced by sexual selection, produces progressive and progressive variability in descending generations. |
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| Formation of new species | “There are as many species as the Almighty created at the beginning of life.” | The views are realNot exist , is a purely speculative concept invented forin order to make it easier to consider collectively a larger numberindividuals, since, according to Lamarck, “in nature there is noanything other than individuals.”Individual variability is continuous, therefore, the boundary between species can be drawn both here and there - where is more convenient. Hereditary variability leads to the formation of progressive and degrading series of organisms, in accordance with the nature of the habitat. Explained the origin of man from the higher “four-armed apes.” | Increasing variability leads to divergence of characters and the formation of new species |
Other scientists: J. Cuvier, J. de Saint-Hilaire, the first Russian evolutionists
Main features of Charles Darwin's theory of evolution
1. Evidence of evolution. Charles Darwin finds evidence of the evolutionary process in many areas of biology, the main provisions of which are contained in three groups of scientifically based facts.Paleontological data. Darwin provides evidence from numerous scientific facts showing that ancient forms of organisms are very different from modern ones, but as we approach modern times, there is an increase in the similarity of fossil forms. This indicates the sequence of evolutionary transformations of living forms. Embryological materials. Comparison of embryos of modern animals that are very distant in their morphological similarity shows a great similarity between them. This can only be explained by unity of origin and family relationships. Biogeographic materials. A comparison of the faunas of oceanic islands that long ago separated from the continents shows, on the one hand, their common origin, and on the other, significant changes in the structure of organisms, which indicate different directions of evolution depending on different conditions of existence.
2. Driving forces of evolution. Darwin considered the following phenomena to be factors in the evolutionary process:variability, heredity and natural selection.
Among the phenomena of variability, he especially distinguished definite and indefinite forms. Of themonly indefinite variability can provide material for evolutionary transformations , because it occurs accidentally, its manifestations are multidirectional, and they can also be inherited, i.e. persist through generations. Charles Darwin considered natural selection to be the main and guiding force in the evolution of organic forms. The theory of natural selection can be summarized as follows:
A. All species of animals and plants strive to increase their numbers. At the same time, the magnitude of variability also increases, i.e. numbers of individuals carrying small, i.e. Relatively harmless to life, deviations in traits that are inherited. This leads to the appearance of a large number of individuals of different quality, with certain characteristics. Living in the natural environment, they find themselves in a state of struggle for existence, both among themselves and between individuals of other species. In harsh environmental conditions, some organisms survive better than others and leave behind offspring with more advantageous hereditary traits.
V. The process of accumulation of useful deviations as a result of such selective average survival of individuals during the struggle for existence was called natural selection by Charles Darwin. In the course of natural selection, nothing is created anew. It is based on existing devices. When environmental conditions remain relatively stable, natural selection preserves existing adaptations. When living conditions change, the average statistical values of the survival of organisms change. Let's assume that the climate in the northern region has warmed sharply. Such phenomena have happened before and are possible in the future. Moreover, the mortality rate of individuals with thick fur may be higher than that of individuals with a genotype that produces less dense fur. Then individuals with hereditary properties that give less dense fur can accumulate in the population. The thinning of fur under warm environmental conditions can be assessed as the emergence of a new adaptation.
Natural selection is the main driving force of evolution . On its basis, in the course of the emergence of more and more new adaptations of organisms that contribute to their better survival and reproduction, a process arisesdivergence (divergences of characteristics of intraspecific groups, the emergence of new species and, on this basis, the identification of genera, families, classes and types). In the constructions of Charles Darwin, the concept of monophyletic evolution developed, showing that all organisms on Earth have common roots of origin. The unity of the entire world of living organisms on our planet is the result of biological evolution based on natural selection.
3. Difficulties, which Charles Darwin experienced when creating his theory:1. Lack of a scientifically developed theory of heredity. At the time Darwin wrote his book, nothing was known about the inheritance of traits. Mendel published his work in 1865, but at that time information spread very slowly, and very few people understood the significance of Mendel's work. His work never reached Darwin. In his experiments, he observed similar phenomena. But I didn’t pay enough attention to this. Therefore, Charles Darwin adhered to the then widespread ideas. That the characteristics of the parents are transmitted to the offspring in half (the theory of mixed inheritance). Because of this, there were difficulties with Jenkin's nightmare, which forced Darwin to partially accept the inheritance of useful adaptations. He even had to come up with the hypothesis of pangenesis (the existence of gemmules that penetrate germ cells and cause variability), which he himself soon abandoned.
2. A small amount of data confirming the operation of selection in natural conditions. There was little such evidence in Darwin's writings. Therefore, he had to first prove the theory of artificial selection, and then move on to proving the theory of natural selection. The theory of artificial selection was a cardinal issue of his evolutionary theory, proving that human activity can quickly and effectively change the characteristics of animals and plants in the direction he needs.
4. Darwin on the species. The consequence of natural selection is the emergence of adaptations that help species to exist more efficiently in the environment. Based on adaptations, it becomes possible to distinguish between varieties, i.e. Within a species, different groups of organisms appear, and then subspecies appear. Thus, instead of the old concept of an absolutely unchanging, stable and morphologically distinct species, Darwin put forward new ideas about a changing species. In his concept, he considered the view as if from two projections:
He represents a species in a given period of time as a really existing natural unit. However, according to Charles Darwin, a species as a real natural unit has a high degree of variability, so that sometimes it is very difficult to distinguish not only the varieties within a species. But also one view from another. A number of transitional forms can also be found between the two species. Therefore, Darwin believed that species are distinct varieties, and varieties are incipient species.
A species over a long historical period of time is a truly evolving unit, undergoing a series of adaptive transformations in its morphological development. At the same time, species characteristics become even more variable and difficult to subdivide, because evolution is slow and gradual.
After the work of Charles Darwin, the evolutionary idea was first united by the concept of a really existing and developing species.
5 . Paths of evolutionary transformations Charles Darwin depicted it in the form of a diagram showing the course of divergent evolution, i.e. evolution with divergence of characters. This scheme especially emphasizes the importance of random factors in evolution, on the basis of which a natural historical process develops, leading to the progressive complication of organisms.
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Target. To acquaint students with the emergence and development of evolutionary ideas, the evolutionary teachings of Charles Darwin.
Methods. Lesson-lecture.
During the classes
1. Explanation
- Lecture plan.
- Terms
- Aristotle and organic evolution
- Carl Linnaeus is the forerunner of evolutionism.
- Evolutionary doctrine of J.B. Lamarck.
- Evolutionary doctrine of Charles Darwin
First, let's get acquainted with the new terms of the topic.
Creationism- the doctrine that life was created by a supernatural being at a specific time.
Metaphysical worldview– (Greek “physis” - nature; “meta” - above) – the original and absolute purposiveness, and therefore the constancy and immutability of all nature.
Transformism- the doctrine of the transformation of one species into another.
Evolution– (Latin evolvo - unfolding / evolutio / - unfolding) a historical change in the form of organization and behavior of living beings in a series of generations.
Aristotle and organic evolution
The new branch of biology is called evolutionary doctrine, or Darwinism, since the theory of evolution was established in biology thanks to the work of the outstanding English scientist Charles Darwin. However, the very idea of evolution is as old as the world. The myths of many peoples are permeated with ideas about the possibility of transformation (transformation) of one species into another. The beginnings of evolutionary ideas can be found both in the works of thinkers of the Ancient East and in the statements of ancient philosophers. 1000 BC e. in India and China It was believed that man descended from apes.
Why do you think?
It’s similar in India, the monkey is a sacred animal and it’s even honorable.
Ancient Greek thinker, philosopher, founder of biology, father of zoology Aristotle (384–322 BC) formulated a theory of the continuous and gradual development of living things from inanimate matter, based on his observations of animals. At the same time, he proceeded from the metaphysical concept of the desire of nature from the simple and imperfect to the more complex and perfect. Aristotle recognized the evolution of the earth's strata, but not the evolution of living organisms, although in his “Ladder of Nature” he grouped and arranged inanimate matter and all living organisms in a certain order from primitive to more complex, which suggested a relationship between living organisms.
Carl Linnaeus is the forerunner of evolutionism.
Carl Linnaeus - Swedish scientist (1707-1778) - the father of botany, the king of flowers, the great systematizer of Nature.
He proposed a simple classification scheme for animals and plants, the best of all previous ones.
a) Linnaeus considered the main systematic unit to be species (a set of individuals similar in structure and producing fertile offspring). The view exists and does not change.
b) He united all species into genera, genera into orders, orders into classes.
c) Linnaeus classified the whale as a mammal, although in the 17th century the whale was considered a fish.
d) Linnaeus, for the first time in the history of science, placed man first in the order of primates in the class of mammals, along with monkeys and prosimians, on the basis of the similarities between man and monkey.
Linnaeus applied a clear, convenient principle of double names.
Before Linnaeus, scientists gave plants only generic names. They were called: oak, maple, rose, pine, nettle, etc. Science used the names of plants by genus, just as is usually done in colloquial everyday language; in relation to plants and animals, long descriptions of characteristics were used to designate the species. So, before Linnaeus, the rose hip was called “Common forest rose with a fragrant pink flower.”
Linnaeus left generic names. He proposed that species names be given in words (most often adjectives) denoting the characteristics of a given plant or animal. The name of plants or animals now consisted of 2 words: in the first place was the generic name (noun), in the second place was the specific name (usually an adjective). For example, Linnaeus named the rosehip in Latin Rosa canina L (Dog rose). L stood for the name of the author who gave the name to this species. In this case Linnaeus.
The very idea of double names was proposed by Kaspar Baugin, i.e. 100 years before Linnaeus, but only Linnaeus realized it.
Linnaeus created the science of botany in the place of former chaos.
a) Conducted a huge reform in the botanical language. In the book "Fundamentals of Botany" he lists about 1000 botanical terms, clearly explaining where and how to use each of them. In fact, Linnaeus invented, albeit taking into account the old terminology, a new language for natural science.
b) Worked on issues of plant biology. Suffice it to recall the "Flora Calendar"
"Clock of flora", "Dream of plants". He was the first to propose conducting phenological observations to determine the best timing of work for agricultural plants.
c) Wrote several large textbooks and study guides on botany.
Linnaeus' system aroused enormous interest in the study and description of plants and animals. Thanks to this, the number of known plant species increased from 7,000 to 10,000 in a few decades. Linnaeus himself discovered and described about 1.5 thousand species of plants, about 2000 species of insects.
The line aroused my interest in studying biology. Many famous scientists, philosophers, and writers became interested in the study of nature thanks to their acquaintance with the works of C. Linnaeus. Goethe said: “After Shakespeare and Spinoza, Linnaeus made the strongest impression on me.”
Despite the fact that Carl Linnaeus was a creationist, the system he developed is alive
nature was built on the principle of similarity, had a hierarchical structure and suggested a relationship between close species of living organisms. Analyzing these facts, scientists came to the conclusion about the variability of species. The authors of these ideas considered the change in species over time as a result of the unfolding (from the Latin “evolvo” - unfolding) of a certain preliminary plan of the Creator, a pre-compiled program in the course of historical development. This point of view is called evolutionist. Such views were expressed in the 18th century. and at the beginning of the 19th century. J. Buffon, W. Goethe, K. Baer, Erasmus Darwin - grandfather of Charles Darwin. But none of them offered a satisfactory explanation of why and how species changed.
Evolutionary doctrine of J.B. Lamarck.
The first holistic concept of evolution was expressed by the French naturalist Jean Baptiste Pierre Antoine de Monier Chevalier de Lamarck (1744-1829).
Lamarck was a deist and believed that the creator created matter according to the laws of its movement, this ended the creative activity of the creator, and all further development of nature occurred in accordance with its laws. Lamarck believed that the most primitive and simple organisms arise through spontaneous generation, and such spontaneous generation occurred many times in the distant past, is happening now and will happen in the future. Organisms, according to Lamarck, could arise from inanimate matter under the influence of light, heat, and electricity.
After their appearance, primitive living organisms do not remain unchanged. They change under the influence of the external environment, adapting to it. As a result of this change, living organisms gradually improve over time over a long series of successive generations, becoming more and more complex and highly organized. As a result, the more time passes from the moment a certain form appears through spontaneous generation, the more perfect and complexly organized its modern descendants turn out to be. The most primitive modern living organisms, in his opinion, arose quite recently and simply did not yet have time to become more perfect and highly organized as a result of gradual complication. All these changes occur over a long period of time and are therefore invisible. But carried away by the denial of the constancy of species, Lamarck begins to imagine living nature as continuous rows of changing individuals; he considers species to be an imaginary unit of classification convenient for the nomenclature of organisms, and in nature only individuals exist. The species is constantly changing and therefore does not exist - he writes in “Philosophy of Zoology” (1809). Lamarck called the stepwise nature of the complication of the organization of living beings gradation. Another new term.
Gradation(lat. ascent) - increasing the organization of living beings from the lowest level to the highest in the process of evolution.
Driving forces of evolution according to Lamarck.
Inner desire for progress, that is, every living creature has an innate internal desire to complicate and improve its organization; this property is inherent in them from the very beginning of nature.
Influence of the external environment, thanks to which, within the same level of organization, various species are formed, adapted to living conditions in the environment.
Any change in the external environment causes organisms only useful changes traits that are inherited as innate properties and only adequate changes, i.e. those that correspond to the changed conditions.
In plants and lower animals The reason for continuous complication and improvement is direct influence of the external environment, causing changes that provide more perfect adaptation to these conditions. Lamarck gives such examples. If the spring was very dry, then meadow grasses grow poorly; spring, with alternating warm and rainy days, causes the same grasses to grow vigorously. Getting from natural conditions into gardens, plants change greatly: some lose thorns and thorns, others change the shape of the stem, the woody stem of plants in hot countries becomes herbaceous in our temperate climate.
In higher animals the external environment valid indirectly involving the nervous system. The external environment has changed - and animals have new needs. If new conditions remain in effect for a long time, then animals acquire corresponding habits. At the same time, some organs are exercised more, others less or completely inactive. An organ that functions intensively develops stronger and becomes stronger, while an organ that is little used for a long time gradually atrophies.
Lamarck explained the formation of a swimming membrane between the fingers of waterfowl by stretching the skin; the absence of legs in snakes is explained by the habit of stretching their body when crawling on the ground, without using their limbs; The giraffe's long front legs are due to the animal's constant efforts to reach the leaves on the trees.
J.B. Lamarck also assumed that the desire of an animal leads to an increased flow of blood and other “fluids” to the part of the body to which this desire is directed, which causes increased growth of this part of the body, which is then inherited.
Lamarck was the first to use the terms “kinship” and “family ties” to denote the unity of origin of living beings.
He quite correctly believed that environmental conditions have an important influence on the course of the evolutionary process.
Lamarck was one of the first to correctly assess the importance of time in the process of evolution and noted the extraordinary duration of the development of life on earth.
Lamarck’s ideas about the branching of the “ladder of beings” and the non-linear nature of evolution prepared the way for the idea of “family trees”, developed in the 60s of the 19th century.
J.B. Lamarck developed a hypothesis about the natural origin of man, suggesting that the ancestors of man were monkeys who switched to a terrestrial lifestyle and walking on the ground from climbing trees. This group (breed) used its hind legs for walking for a number of generations and eventually went from being four-armed to being two-armed. If this breed stopped using its jaws to tear apart prey and began to chew it, this could lead to a decrease in the size of the jaw. This most developed breed took over all convenient places on earth, displacing less developed breeds. Individuals of this dominant breed gradually accumulated ideas about the world around them; they developed a need to convey these ideas to their own kind, which led to the development of various gestures, and then speech. Lamarck pointed out the important role of the hand in the development of man.
He tried to explain the origin of domestic animals and cultivated plants. Lamarck said that the ancestors of domestic animals and cultivated plants were taken by man from the wild, but domestication, changes in diet and crossing made these forms unrecognizable in comparison with wild forms.
Evolutionary doctrine of Charles Darwin.
2. Charles Darwin about the species.
The view exists and changes
Driving forces of evolution according to Charles Darwin.
- Heredity.
- Variability.
- Natural selection based on the struggle for existence.
3. Homework assignment. Paragraphs 41, 42 to art.
4. Consolidation.
- What did Aristotle think about the evolution of living organisms?
- Why is Carl Linnaeus called the herald of evolutionism?
- Why is the evolutionary teaching of J.B. Lamarck was not recognized by his contemporaries?
- What do you know about the evolutionary teachings of Charles Darwin?
Carl Linnaeus
To systematize the huge number of descriptions of animals and plants, some kind of taxonomy unit was required. Linnaeus took the species as such a unit, common to all living things. Linnaeus called a species a group of individuals similar to each other, like children of the same parents and their children. A species consists of many similar individuals that produce fertile offspring. The entire organic world consists of various types of plants and animals.
Linnaeus began naming species in Latin, which was the international language of science at that time. Thus, Linnaeus resolved a difficult problem: after all, when names were given in different languages, the same species could be described under many names.
A very important achievement of Linnaeus was the introduction into practice of double species names (binary nomenclature). He suggested calling each species in two words. The first is the name of the genus, which includes closely related species. For example, lion, tiger, and domestic cat belong to the genus Felis (Cat). The second word is the name of the species itself (Felis leo, Felis tigris, Felis domestica, respectively).
Human(whom he dubbed “Homo sapiens,” Homo sapiens) Linnaeus, quite boldly for his time, placed the order of primates in the class of mammals along with monkeys. He did this 120 years before Charles Darwin. He did not believe that humans descended from other primates, but he saw great similarities in their structure.
Linnaeus' system of plants and animals was largely artificial, it did not reflect the course of historical development of the world. Linnaeus was aware of this shortcoming of his system and believed that future naturalists should create a natural system of plants and animals, which should take into account all the characteristics of organisms, and not just one or two characteristics. The science of that time did not have the knowledge necessary for this.
Linnaeus believed that plant and animal species do not change; they have retained their characteristics “since creation.” According to Linnaeus, every modern species is the offspring of an original divinely created parent pair. Each species reproduces, but retains, in his opinion, unchanged all the features of this ancestral pair.
As a good observer, Linnaeus could not help but see the contradiction between the ideas of the complete immutability of plants and animals with what is observed in nature. He allowed the formation of varieties within a species due to the influence of climate change and other external conditions on organisms.
Jean Baptiste Lamarck
Jean Baptiste Lamarck, a French researcher, became the first biologist to try to create a coherent and holistic theory of the evolution of the living world. Not appreciated by his contemporaries, half a century later his theory became the subject of heated discussions that have not stopped in our time.
The most Lamarck’s important work was the book “Philosophy of Zoology,” published in 1809. In it, he outlined his theory of the evolution of the living world. The basis of Lamarck's views was the position that matter and the laws of its development were created by a creator. Lamarck analyzed the similarities and differences between living and nonliving matter and listed them. The most important of these differences is the ability to respond to external stimuli. In his opinion, the reason for life lies not in the living body itself, but in something outside it.
Lamarck introduced the concept of gradation - the internal “striving for improvement” inherent in all living things; the action of this factor of evolution determines the development of living nature, the gradual but steady increase in the organization of living beings - from the simplest to the most perfect. The result of gradation is the simultaneous existence in nature of organisms of varying degrees of complexity, as if forming a hierarchical ladder of creatures. Considering gradation to be a reflection of the main trend in the development of nature, Lamarck tried to give this process a materialistic interpretation: in a number of cases, he associated the complication of organization with the action of fluids penetrating the body from the external environment.
Another factor of evolution is the constant influence of the external environment, leading to a violation of the correct gradation and causing the formation of a whole variety of adaptations of organisms to environmental conditions. Environmental change is the main cause of speciation; as long as the environment is constant, species remain constant; if there is a shift in it, the species change.
Life, according to Lamarck, can spontaneously arise on Earth and continues to arise at the present time. In the 17th century, there were ideas that darkness and grain were needed for the spontaneous generation of mice, and rotten meat for the spontaneous generation of worms. Lamarck suggests that single-celled organisms are capable of spontaneous generation, and that all animals and plants that have a higher organization appeared as a result of the long-term development of living organisms.
Lamarck introduces two laws of development of living nature:“The law of exercise and non-exercise of organs” and “The law of inheritance of acquired characteristics.”
The first law can be called the law of variability, in which Lamarck focuses on the fact that the degree of development of a particular organ depends on its function, the intensity of exercise, and that young animals that are still developing are more capable of change. The scientist opposes the metaphysical explanation of the form of animals as unchangeable, created for a specific environment. At the same time, Lamarck overestimates the importance of function and believes that exercise or non-exercise of an organ is an important factor in changing species.
The second law can be called the law of heredity; It should be noted that Lamarck associates the inheritance of individual changes with the duration of the influence of the conditions that determine these changes, and due to reproduction, their intensification in a number of generations. It is also necessary to emphasize the fact that Lamarck was one of the first to analyze heredity as an important factor in evolution. At the same time, it should be noted that Lamarck’s position on the inheritance of all characteristics acquired during life was erroneous: further research showed that only hereditary changes are decisive in evolution.
Lamarck extends the provisions of these two laws to the problem of the origin of breeds of domestic animals and varieties of cultivated plants, and also uses them to explain the animal origin of humans. Human Origins.
Linnaeus: In plant taxonomy, he took species as the unit of classification. He described over 8 thousand plants and 4,200 animals. K. Linnaeus classified all plants according to the number and structure of stamens and pistils into 24 classes. He divided classes into orders, orders into genera, genera into species. K. Linnaeus gave each plant a species and generic name in Latin. This method of designation is called binary (double) nomenclature. K. Linnaeus introduced the names for parts of a flower: petal, anther, stamen filaments, nectary, ovary and stigma, receptacle, peduncle, perianth. Linnaeus classified the fauna into six classes based on the structure of the circulatory and respiratory organs: 1) mammals; 2) birds; 3) amphibians; 4) fish; 5) insects; 6) worms. He divided mammals into 17 orders. The unification of the class of mammals only by mammary glands led to the fact that oviparous mammals (echidna, platypus), pinnipeds and cetaceans fell into this class. The system created by K. Linnaeus was artificial: it helped to recognize plants, but did not fully reveal their family relationships. When classified according to 1-2 arbitrarily chosen characteristics, systematically distant plants sometimes ended up in the same class, and related ones - in different ones. For example, when counting the number of stamens in carrots and flax, Linnaeus placed them in the same group on the basis that they each had five stamens per flower. In fact, these plants belong to different genera and families: carrots are from the Apiaceae family, flax is from the flax family.
Lamarck: The advantage of J.B. Lamarck's evolutionary theory is a more in-depth study of the structure of plants and animals, which was based on specific scientific data. In his work “Philosophy of Zoology” (1809), he proved the variability of the organic world using many examples. J. B. Lamarck was also involved in the taxonomy of animals. For the first time, based on similar characteristics, animals were divided into “vertebrates” and “invertebrates”; he grouped them into six levels and fourteen classes:
Of these, only invertebrates were divided into 10 classes:
Until now, crustaceans and arachnids have been studied as separate classes. Molluscs and bristle worms are combined into a phylum. Thus, J.B. Lamarck laid the foundation for the classification of the natural system. According to J.B. Lamarck, life arises through the spontaneous generation of the simplest living bodies, while there is a consistent complication of living nature from the lowest to the highest. Since the evolutionary ideas of J.B. Lamarck were supported by factual material, the first evolutionary theory arose. J.B. Lamarck believed that the main factors of evolution in the emergence of a new species are the external environment and time. He especially emphasized the role of the environment - changes in hydrogeological conditions and climate change. But due to the limitations of science of that period, J.B. Lamarck was unable to comprehensively prove the evolutionary theory and correctly explain the reason for the changes in organisms, and was unable to reveal the driving forces (factors) of evolution.
He assumed as the main factor of evolution the adequate direct influence of the environment, in particular the influence of organ exercise, which leads to the strengthening of these organs not only in a particular individual, but in its offspring. As a result, organs that are constantly in motion change and develop, while organs that receive little exercise shrink and atrophy. For example, the presence of a long neck in a giraffe is explained by a change in the behavior of the animal's ancestors, who had to stretch their necks to reach leaves on trees; the absence of legs in a snake is the habit of stretching its body when crawling on the ground, without using its limbs.
J. B. Lamarck also admitted that the desire, the desire of an animal, leads to increased blood flow to the part of the body to which this desire is directed, which causes increased growth of this part of the body, which is then inherited. But due to the failure of the science of that period, J.B. Lamarck was unable to comprehensively prove the evolutionary theory. However, 50 years later, the English scientist Charles Darwin proved the causes and patterns of evolution of the organic world.
Darwin: The main driving force of evolution according to Darwin is natural selection. Selection, acting on individuals, allows those organisms that are better adapted for life in a given environment to survive and leave offspring. The action of selection leads to the disintegration of species into parts - daughter species, which, in turn, diverge over time into genera, families and all larger taxa.
Secondly, and this is the most important thing, Darwin was able to explain to his contemporaries the reasons for the variability of species based on his observations. He rejected, as untenable, the idea of “exercising” or “non-exercising” organs and turned to the facts of the breeding of new breeds of animals and varieties of plants by people - to artificial selection. He showed that indefinite variability of organisms (mutations) are inherited and can become the beginning of a new breed or variety, if it is useful to humans. Having transferred these data to wild species, Darwin noted that only those changes that are beneficial to the species for successful competition with others can be preserved in nature, and spoke about the struggle for existence and natural selection, to which he attributed an important, but not the only role as the driver of evolution. Darwin not only gave theoretical calculations of natural selection, but also showed, using factual material, the evolution of species in space, with geographic isolation (finches) and explained the mechanisms of divergent evolution from the standpoint of strict logic. He also introduced the public to the fossil forms of giant sloths and armadillos, which could be seen as evolution through time. Darwin also allowed for the possibility of long-term preservation of a certain average norm of a species in the process of evolution by eliminating any deviating variants (for example, sparrows that survived a storm had an average wing length), which was later called stasygenesis. Darwin was able to prove to everyone the reality of the variability of species in nature, therefore, thanks to his work, ideas about the strict constancy of species came to naught. It was pointless for staticists and fixists to continue to persist in their positions.
Introduction 2
1. Carl Linnaeus: taxonomy of flora and fauna 4
2. Transition from the idea of transformation of species to the idea of evolution. J.-B. Lamarck: the concept of evolution of the organic world 7
3. Charles Darwin: founder of the theory of evolution 11
3.1. The history of Darwin's theory of evolution 11
3.2. Basic principles of the theory of evolution of Charles Darwin 12
4. Formation of a synthetic theory of evolution. The doctrine of N. I. Vavilov on the origin of cultivated plants 18
4.1. The twentieth century is the century of genetics. Creation of a synthetic theory of evolution 18
4.2. Nikolai Vavilov: human influence on evolution 20
Conclusion 24
References 25
Introduction
Life on Earth... The richness of its forms is amazing! Life penetrated into the depths of the ocean and beyond the Arctic Circle, rose to the tops of the highest mountains and rarefied layers of the atmosphere, where many types of microorganisms were found. Have life forms always been the way we see them today, or have they gone through a long development process over the centuries? - this is the question that arises in everyone who sees such a variety of living beings.
Since ancient times, people have answered it in different ways. According to the biblical book of Genesis, “On the third day God created the plant world: the grass that yields seed, the fruitful tree that bears fruit according to its kind, in which is its seed on the earth.” On the fifth day, “God created the great fish and every living creature that moves, which the waters brought forth, according to their kinds, and every winged bird according to its kind.” On the sixth day He created “the beasts of the earth according to their kinds, and the cattle according to their kinds, and every creeping thing that creeps on the earth according to their kinds” (Gen. 1:11,21,25).
The extreme complexity of the structure and the observed expediency of the behavior of living organisms led many to the opinion that life is something more than just a physical and chemical phenomenon. Living beings, in comparison with objects of inanimate nature, have a number of distinctive properties, thanks to which a very specific goal is achieved. In this regard, since ancient times, an idea has arisen: although living beings are material, living matter is apparently “animated” by a certain immaterial factor. This point of view was and is held by many people of different religious and philosophical beliefs. This point of view underlies vitalism - a movement in biology that recognizes the presence in organisms of an immaterial supernatural force (“life force”, “soul”, etc.) that controls life phenomena.
The results of modern experiments show that the fundamental laws of nature (the laws of conservation of mass and energy) in living systems are fulfilled within the limits of experimental accuracy. Numerous experiments show that in biological systems not a single law of physics and chemistry is violated. However, it is hasty to draw a conclusion from this statement: living systems obey only the laws of physics and chemistry.
With a very great degree of caution, we can say: living things are a material system endowed with the property of purposefulness. Of course, this statement does not pretend to be a complete exhaustive definition of living systems, and, of course, with the development of natural science and science in general, it will certainly be specified, supplemented and, therefore, modified.
Since ancient times, there has been an idea of gradual modification of living forms. This idea was quite clearly expressed by the ancient Greek philosopher Empedocles. And yet, for many centuries, the idea of the immutability of the forms of the organic world remained dominant, and the reason for this, most likely, is that man, in the apt expression of Charles Darwin, looked at the organic world “as a savage looks at a ship, that is, as something beyond his understanding."
The concept of evolution is used in different senses, but for the most part it is identified with development. Evolution (Latin evolutio - deployment) is one of the forms of movement in nature and society - a continuous, gradual quantitative change, in contrast to revolution. When considering the evolution of living nature, evolution meant the process of long-term, gradual, slow changes, which ultimately lead to radical, qualitative changes, culminating in the emergence of new material systems, structures, forms and species. This is precisely the meaning given to the concept of evolution in Darwin’s theory and the hypotheses and theories that appeared after him.
This course work examines the main ideas of C. Linnaeus, J.-B. Lamarck, C. Darwin, N. Vavilov, who made a great contribution to the development of evolutionary theory, which summarized the results of their discoveries in the field of heredity, variability and natural selection.
The purpose of writing the course work is to study the problem of the existence of species and evolution in the works of C. Linnaeus, J.-B. Lamarck, C. Darwin, N. Vavilov. To achieve this goal, I solved the following tasks:
To characterize the artificial classification given by C. Linnaeus, to show its significance for the formation of the theory of evolution;
Consider the concept of evolution of the organic world by J.-B. Lamarck within the framework of the process of transition from the idea of transformation of species to the idea of evolution;
Highlight the basic principles of Charles Darwin’s theory of evolution, give a brief description of the history of this theory;
