1.2.3 Classical science. Stage of mechanistic natural science.

The origin and formation of evolutionary ideas

Classical science. Most historians of science believe that science, as a unique form of knowledge - a specific type of knowledge production and a social institution, arose in Europe, in modern times, in the era of the formation of the capitalist mode of production and the differentiation of previously unified knowledge into philosophy and science. Science begins to develop relatively independently. The period of formation of classical science begins approximately in the 16th – 17th centuries. and ends at the turn of the 19th – 20th centuries. It, in turn, can be divided into two stages: the stage of mechanistic natural science (until the 30s of the 19th century) and the stage of the emergence and formation of evolutionary ideas (until the end of the 19th - beginning of the 20th century).

Stage of mechanistic natural science. Rapid development of productive forces (industry, mining and military affairs, transport, etc.) during the transition period Western Europe, from feudalism to capitalism required the solution of a number of technical problems. And this, in turn, caused the intensive formation and development of special sciences, among which special

mechanics gained importance. The idea of ​​the possibility of changing, remaking nature, based on knowledge of its laws, is becoming stronger, and the practical value of scientific knowledge. Mechanistic natural science begins to develop at an accelerated pace.

The stage of mechanistic natural science, in turn, can be conditionally divided into two stages - pre-Newtonian and Newtonian, respectively associated with two global scientific revolutions * that took place in the 16th - 17th centuries. and created a fundamentally new (compared to antiquity and the Middle Ages) understanding of the world.

The first scientific revolution that occurred during the Renaissance is associated with the emergence of the heliocentric doctrine of N. Copernicus (1473–1543). It marked the end of the geocentric system, which Copernicus rejected on the basis large number astronomical observations and calculations. He defended the thesis about the infinity of the Universe, about the countless number of worlds similar to the solar system. In addition, Copernicus expressed the idea of ​​motion as a natural property of material objects that obey certain laws, and pointed out the limitations of sensory knowledge. This teaching destroyed the usual religious picture of the world.

The theories of Galileo, Kepler and Newton are associated with the second scientific revolution - the post-Newtonian stage of development of mechanistic natural science. The teachings of G. Galileo (1564–1642) already laid quite strong foundations for a new mechanistic natural science. The problem of movement was at the center of his scientific interests. The discovery of the principle of inertia and his study of the free fall of bodies were of great importance for the development of mechanics as a science. Galileo was the first to introduce into knowledge a thought experiment based on a strict quantitative and mathematical description and which became a characteristic feature of scientific knowledge. Galileo showed that science without mental construction, without idealization, without abstractions, without “generalizing resolutions” based on facts is anything but science. Galileo was the first to show that experimental data in their primordial form is not at all the initial element of knowledge, that they always need certain theoretical prerequisites. In other words, experience cannot but be preceded by certain theoretical assumptions, it cannot but be “theoretically loaded.”

Johannes Kepler (1571–1630) established the laws of planetary motion relative to the Sun. In addition, he proposed a theory of solar and lunar eclipses and methods for predicting them, clarified the distance between the Earth and the Sun, etc. However, Kepler did not explain the reasons for the movement of the planets, because dynamics - the study of forces and their interaction - was created later by Newton.

* We will specifically focus on the role of scientific revolutions in the development of science in section 2.1.2 when considering the issue of the development of scientific knowledge.

It should be noted that in the 17th century. the status of science is being consolidated as a special social institution. In 1662, the Royal Society of London emerged, which united amateur scientists into a voluntary organization with a specific charter sanctioned by the highest government authority - the king. The charter of the Royal Society of London states that its purpose is “to improve the knowledge of natural subjects and all useful arts by means of experiments...”. The Royal Society sought to promote and support empiricism. A hypothesis put forward by someone was subjected to empirical testing, in an experiment, and was either accepted and maintained, or inevitably rejected if the evidence of an empirical fact was unfavorable for it. Members of society rejected work performed according to other standards.

Some researchers associate the birth modern science with the emergence of university research laboratories and with the conduct of research of important practical importance. This was first carried out at the University of Berlin under the leadership of Wilhelm Humboldt.

At the end of the 16th - beginning of the 17th centuries. There is a bourgeois revolution in the Netherlands, and from the middle of the 17th century. - in England, the most industrially developed European country. Bourgeois revolutions gave impetus to the development of industry and trade, construction, mining and military affairs, navigation, etc. The expansion of trade relations, the opening of new markets for raw materials and the sale of goods contributed to the development of such disciplines as astronomy, mathematics and mechanics. The fruit of the revolution in worldview was a new attitude towards science, the undermining of trust in the church and in the works of ancient scientists, whose authority shackled minds, and the widespread introduction into science of a research method based on accurate observation and experience.

During the period of formation of experimental-mathematical natural sciences, astronomy, mechanics, physics, chemistry and other special sciences gradually developed into independent branches of knowledge. In contrast to traditional (especially scholastic) philosophy, modern science has raised questions in a new way about the specifics of scientific knowledge and the originality of its formation, about the tasks cognitive activity and its methods, about the place and role of science in the life of society, about the need for human domination over nature based on knowledge of its laws.

The second scientific revolution ended with the work of Newton (1643–1727), whose scientific heritage is extremely deep and varied. Newton's main work is “Mathematical Principles of Natural Philosophy” (1687). In this and his other works, Newton formulated the concepts and laws of classical mechanics, gave a mathematical formulation of the law of universal gravitation, theoretically substantiated Kepler's laws and, from a single point of view, explained a large amount of experimental data (inequalities in the motion of the Earth, Moon and planets, sea tides, etc.) . In addition, Newton, independently of Leibniz, created differential and integral calculus as an adequate language for the mathematical description of physical reality. Newton's scientific method aimed at clearly contrasting reliable natural science knowledge with the fictions and speculative schemes of natural philosophy.

1) conduct experiments, observations, experiments;

2) through induction, isolate individual aspects of the natural process in their pure form and make them objectively observable;

3) understand the fundamental laws, principles, and basic concepts that govern these processes;

4) carry out a mathematical expression of these principles, i.e. mathematically formulate the relationships of natural processes;

5) build a holistic theoretical system by deductively unfolding fundamental principles, i.e., “to arrive at laws that have unlimited force throughout the entire cosmos”;

6) “to use the forces of nature and subordinate them to our goals in technology.”

Many important scientific discoveries have been made using this method. Based on Newton’s method, during the period under review, a huge arsenal of a wide variety of methods was developed and used: observation, experiment, induction, deduction, analysis, synthesis, mathematical methods, idealization, etc. More and more often they began to talk about the need to combine various methods.

The foundation built by Newton turned out to be extremely fruitful and until the end of the 19th century. was considered unshakable.

Despite the limited level of natural science in the 17th century, the mechanical picture of the world played a generally positive role in the development of science and philosophy. It provided a natural scientific understanding of many natural phenomena, freeing them from mythological and religious scholastic interpretations. It focused on understanding nature from itself, on understanding the natural causes and laws of natural phenomena.

The materialistic orientation of Newton's mechanical picture did not free it from certain shortcomings and limitations. The mechanistic, metaphysical nature of Newton's thinking is manifested in his statement that matter is an inert substance, doomed to eternally repeat the course of things, evolution is excluded from it; things are motionless, devoid of development and interconnection; time is pure duration, and space is an empty “container” of matter, existing independently of matter, time and in isolation from them. Feeling the insufficiency of his picture of the world, Newton was forced to appeal to the ideas of divine creation, paying tribute to religious idealistic ideas.

However, this period is characterized by the development of mechanics, mathematics and the desire to use quantitative methods in many areas of scientific knowledge. One of the leading research techniques is measurement.

The pioneers who proclaimed measurement the basis of accurate knowledge, including in relation to the study of living nature, were G. Galileo (1564–1672), Santorio (1561–1636), D. A. Borelli (1608–1679).

Santorio is the author of the work “On Static Medicine” and other works, invents measuring instruments, measures metabolism, tries to establish the norm and pathology in the development of the body. Galileo and his student Borelli studied the mechanics of animal movement and established the relationship between their motor functions and the absolute size of the body.

The formation of mathematical statistics also dates back to this time. Well-known credit for this belongs to the English school of “political arithmeticians” led by Petty (1623–1687).

The unprecedented successes of mechanics gave rise to the idea that all processes in the world are fundamentally reducible to mechanical ones. Therefore, mechanics was directly identified with exact natural science. Its tasks and scope seemed limitless.

Thus, the English chemist R. Boyle (1627–1691) put forward a program that transferred to chemistry the principles and models of explanation formulated in mechanics.

In 1628, the English physician, anatomist and physiologist William Harvey (1578–1657) published his work “An Anatomical Study of the Movement of the Heart and Blood in Animals.” In this work, for the first time, a correct understanding of the systemic and pulmonary circulation and the heart as the engine of blood in the body was given.

The discovery of the reflex by the French philosopher, mathematician and physiologist René Descartes (1596–1650) was of great importance for the development of physiology, although the reflex process itself in his view had a mechanical explanation.

Lamarck, trying to find the natural causes of the development of organisms, also relied on a version of the mechanical picture of the world.

Mechanism appeared in the works of physiologists, for example, the French philosopher and physician J. La Mettrie (1709–1751) argued that the human body is a self-winding machine. D. A. Borelli, the author of the essay “On the Movement of Animals,” argued that “the actions of animals are performed as a result of, through and on the basis of mechanical phenomena.”

The chemist A. L. Lavoisier (1743–1794) and the mathematician P. S. Laplace (1749–1827) made the first measurements of the body’s energy expenditure.

In the middle of the 17th century. The work of Pierre Fermat (1601–1665), Blaise Pascal (1623–1662) and Christian Huygens (1629–1695) laid the foundations for the theory of probability. Subsequently, thanks to the works of A. Moivre (1667–1754) and especially P. S. Laplace, C. Gauss (1777–1855), Poisson (1781–1840) and other mathematicians who discovered the laws of distribution of random variables, probability theory became a solid scientific basis and finds application in solving a number of practical problems. The first to successfully combine the empirical methods of anthropology and social statistics with the mathematical theory of probability was Laplace's student, the Belgian Adolphe Quetelet (1796–1874). In 1835, his book “On Man and the Development of His Abilities or the Experience of Social Physics” was published, in which, using large statistical material, it was shown that various physical characteristics of a person and even his behavior are subject to the laws of probability distribution. In “Anthropometry” (1871), Quetelet noted that the patterns he described apply not only to humans, but also to all other living beings. Quetelet laid the foundations of biometrics. The mathematical apparatus of this science was created by the followers of the English school of biometricians F. Galton (1822–1911) and K. Pearson (1857–1936). In the 20th century classical works by W. Gosset (1876–1937), who published under the pseudonym “Student”, R. A. Fisher (1890–1967) and others appeared. The name of Student is associated with the rationale for the so-called “small sample theory,” which opened a new page in the history of biometrics. R. Fischer developed a method of analysis of variance, which has found application not only in biology, but also in technology. Domestic scientists made a great contribution to the development of mathematical methods used in biology: V. I. Romanovsky (1879–1954), S. I. Bernstein (1880–1969), A. Ya. Khinchin (1894–1959), A. N. Kolmogorov (1903–1987), V. S. Nemchinov (1894–1946), M. V. Ignatiev (1894–1959) and many others. Our scientists have done a lot in the field of biometric training of biologists and specialists in disciplines related to biology: Pomorsky, (1893–1954); P. V. Terentyev (1903–1970); Yu. A. Filipchenko (1882–1930); S. S. Chetverikov (1880–1959) and others.

The progress of experimental knowledge, experimental science, observed in modern times, led to the replacement of the scholastic method of thinking with a new method of cognition, addressed to real world. The principles of materialism and elements of dialectics were revived and developed, and the process of demarcation between philosophy and special sciences developed at an accelerated pace. However, as the mechanical picture of the world expanded to new subject areas, science increasingly faced the need to take into account the features of these areas, requiring new, non-mechanical concepts. Facts accumulated that were increasingly difficult to reconcile with the principles of the mechanical picture of the world. It was losing its universal character, splitting into a number of specific scientific pictures, and the process of loosening the mechanical picture of the world began. In the middle of the 19th century. it has finally lost its general scientific status.

The origin and formation of evolutionary ideas. From the end of the 18th century. in the natural sciences, facts and empirical material accumulated that did not “fit” into the mechanical picture of the world and were not explained by it. The “undermining” of this picture of the world came mainly from two sides: firstly, from the side of physics itself and, secondly, from the side of geology and biology.

The first line of “undermining” was associated with research in the field of electric and magnetic fields by English scientists M. Faraday (1791–1867) and D. Maxwell (1831–1879). Faraday discovered the relationship between electricity and magnetism, introduced the concepts of electric and magnetic fields, and put forward the idea of ​​​​the existence of an electromagnetic field. Maxwell created electrodynamics and statistical physics, built a theory of the electromagnetic field, predicted the existence of electromagnetic waves, and put forward the idea of ​​​​the electromagnetic nature of light. Thus, matter appeared not only as a substance (as in the mechanical picture of the world), but also as an electromagnetic field.

Since electromagnetic processes were not reduced to mechanical ones, the conviction began to form that the basic laws of the universe are not the laws of mechanics, but the laws of electrodynamics. Work in the field of electromagnetism greatly undermined the mechanical picture of the world and essentially marked the beginning of its collapse. Since then, the mechanical picture of the world began to fade from the historical scene, giving way to a new understanding of physical reality.

The second direction of “undermining” the mechanical picture of the world is connected by the works of the English geologist C. Lyell (1797–1875) and the French biologists J. B. Lamarck (1744–1829) and J. Cuvier (1769–1832).

J.B. Lamarck created the first holistic concept of the evolution of living nature. In his opinion, species of animals and plants are constantly changing, becoming more complex in their organization as a result of the influence of the external environment and a certain internal desire of all organisms for improvement.

In the first decades of the 19th century. the “overthrow” of the metaphysical way of thinking was actually prepared, this was facilitated by three great discoveries: the creation of the cellular theory, the discovery of the law of conservation and transformation of energy, and the development by Charles Darwin (1809–1882) of evolutionary theory.

The cell theory, created by German scientists M. Schleiden (1804–1881) and T. Schwann (1810–1882) in 1838–1839, proved the internal unity of all living things and pointed to the unity of origin and development of all living beings. It established a common origin, as well as the unity of the structure and development of living nature.

Of great importance for the development of natural science were the discovery by M. V. Lomonosov (1711–1765) of the law of conservation of matter and motion, and the subsequent establishment by J. Mayer (1814–1878), D. Joule (1818–1889) and G. Helmholtz ( 1821–1894) law of conservation and transformation of energy. It was proven that the so-called “forces” that were previously recognized as isolated - heat, light, electricity, magnetism, etc. - are interconnected, transform into one another under certain conditions and represent only different forms of the same movement in nature. Energy, as a general quantitative measure of various forms of motion of matter, does not arise from nothing and does not disappear, but can only pass from one form to another. This fundamental discovery, in addition to its general ideological significance, also influenced the development of plant and human physiology. The cycle of energy in nature, in the plant organism, became clear. As K. A. Timiryazev (1843–1920) showed, the free energy of solar rays is converted into chemical energy of complex organic compounds formed in a green plant during the process of photosynthesis; In an animal organism, the chemical energy of organic compounds obtained from food, when broken down, is released and converted into kinetic types of energy: thermal, mechanical, electrical.

The evolutionary theory of Charles Darwin (1809–1882), finally formalized in his main work “The Origin of Species by Means of Natural Selection” (1859), showed that plant and animal organisms (including humans) were not created by God, but are the result of natural development ( evolution) of the organic world and originate from a few simple creatures that originated from inanimate nature. Thus, the material factors and causes of evolution were found - heredity and variability - and the driving factors of evolution - natural selection for organisms living in the “wild” nature, and artificial selection for domestic animals and cultivated plants bred by humans. Subsequently, Darwin's theory was confirmed by genetics, which showed the mechanism of changes on the basis of which the theory of natural selection can work. In the middle of the 20th century, especially in connection with the discovery of the structure of DNA in 1953 by F. Crick (1916–2004) and J. Watson (born 1928), the so-called systematic theory of evolution was formed, combining classical Darwinism and the achievements of genetics.

In the second half of the 19th century, thanks to the work of chemists, the amount of heat released when basic nutrients were burned outside the body, in other words, their caloric value. At the same time, physiologists developed methods that made it possible to take into account the amount of energy released by the body during rest and work of varying severity.

Significant results were obtained thanks to the creation of a method of electrical stimulation and graphic recording of organ activity using special instruments: kymograph, myograph, sphygmograph, etc. In this regard, the merits of the German physiologist E. Dubois-Reymond (1818–1896), who developed in detail the method of electrical irritation of living tissues. Research on electrical phenomena observed in the body, begun by L. Galvani (1773–1798) and A. Volta (1745–1827) and continued by N. E. Vvedensky (1852–1922), brought us closer to understanding the physiological process of excitation. At the same time, I. M. Sechenov (1829–1905) and V. Ya. Danilevsky (1852–1939) were the first to study electrical phenomena in nerve centers, which attracted particular interest from physiologists in the 20th century. Of outstanding importance were the works of I.M. Sechenov, who in 1862 discovered the process of inhibition in the central nervous system, and in 1863 published the brilliant work “Reflexes of the Brain.”

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When considering ideas about living nature in ancient world Let us briefly dwell only on the main conclusions made at that time and which were of particular importance for the development of natural science.

The first attempts to systematize and generalize scattered information about the phenomena of living nature belonged to ancient natural philosophers, although long before them, the literary sources of various peoples (Egyptians, Babylonians, Indians and Chinese) provided a lot of interesting information about the flora and fauna.

Ancient natural philosophers put forward and developed two main ideas: the idea of ​​the unity of nature and the idea of ​​its development. However, the causes of development (movement) were understood mechanistically or teleologically. Thus, the founders of ancient Greek philosophy Thales (VII - VI centuries BC), Anaximander (610 - 546 BC), Anaximenes (588 - 525 BC) and Heraclitus (544 - 483 BC . e.) tried to identify the original material substances that determined the emergence and natural self-development of the organic world. Despite the fact that they naively resolved this issue, considering water, earth, air or anything else to be such substances, the very idea of ​​​​the emergence of the world from a single and eternal material source had important. This made it possible to break away from mythological ideas and begin an elementary causal analysis of the origin and development of the surrounding world.

Of the natural philosophers of the Ionian school, Heraclitus of Ephesus left a special mark on the history of science. He was the first to introduce into philosophy and the science of nature a clear idea of ​​the constant change and unity of all bodies of nature. According to Heraclitus, “the development of every phenomenon or thing is the result of the struggle of opposites that arises in the system or thing itself.” The rationale for these conclusions was primitive, but they laid the foundation for a dialectical understanding of nature.

The idea of ​​the unity of nature and its movement developed in the works of Alcmaeon of Croton (late 6th - early 5th century BC), Anaxagoras (500 - 428 BC), Empedocles (about 490 - 430 BC) and, finally, Democritus (460 - 370 BC), who, based on the ideas of his teacher Leucippus, created the atomic theory. According to this theory, the world consists of the smallest indivisible particles - atoms, moving in the void. Movement is inherent in atoms by nature, and they differ from each other only in shape and size. Atoms are unchanging and eternal, they were not created by anyone and will never disappear. According to Democritus, this is enough to explain the emergence of natural bodies - inanimate and living: since everything consists of atoms, the birth of any thing is a union of atoms, and death is their separation. Many natural philosophers of that time tried to solve the problem of the structure and development of matter from the standpoint of atomic theory. This theory was the highest achievement of the materialist line in ancient natural philosophy.

In the IV-III centuries. BC e. The idealistic system of Plato (427 - 347 BC) was opposed to the materialistic direction. She also left a deep mark on the history of philosophy and science. The essence of Plato's teachings boiled down to the following. The material world is represented by the totality of emerging and transitory things. It is an imperfect reflection of ideas comprehended by the mind, ideal eternal images of objects perceived by the senses. The idea is the goal and at the same time the cause of matter. According to this typological concept, the observed wide variability of the world is no more real than the shadows of objects on the wall. Only the constant, unchanging “ideas” hiding behind the visible variability of matter are eternal and real.

Aristotle (384 - 322 BC) tried to overcome Platonic idealism, asserting the reality of the material world and its existence in a state of constant movement. He first introduces the concept of various forms of movement and develops a sensualistic theory of knowledge. According to Aristotle's theory, the source of knowledge is sensations, which are then processed by the mind. However, Aristotle failed to completely move away from the typological concept. As a result, he modified Plato’s idealistic philosophy: he considered matter passive and contrasted it with an active immaterial form, explaining natural phenomena from a theological point of view and at the same time admitting the existence of a divine “first mover.”

In all bodies, he distinguished two sides - matter, which has different capabilities, and form, under the influence of which this possibility is realized. Form is both the cause and the goal of the transformations of matter. Thus, according to Aristotle, it turns out that matter is in motion, but the cause of this is an immaterial form.

The materialistic and idealistic teachings of the ancient Greek natural philosophers had their supporters in ancient Rome. These are the Roman poet and philosopher Lucretius Car (1st century BC), naturalist and first encyclopedist Pliny (23 - 79 AD), physician and biologist Galen (130 - 200 AD), who made a significant contribution in the development of anatomy and physiology of humans and animals.

By the 6th century n. e. the basic ideas of ancient natural philosophers became widespread. By this time, a relatively large amount of factual material had already accumulated about various natural phenomena and the process of differentiation of natural philosophy into special sciences had begun. Period from VI to XV centuries. conventionally called "the Middle Ages". As already noted, during this period feudalism emerged with its characteristic political and ideological superstructure, the mainly idealistic direction, left as a legacy by ancient natural philosophers, developed, and the idea of ​​nature was based primarily on religious dogmas.

Taking advantage of the achievements of ancient natural philosophy, the monastic scientists of the Middle Ages defended religious views that promoted the idea of ​​a world order expressing the divine plan. This symbolic vision of the world is a characteristic feature of medieval thinking. The Italian Catholic theologian and scholastic philosopher Thomas Aquinas (1225 - 1274) expressed this in the following words: “Contemplation of creation should not have as its goal the satisfaction of a vain and transitory thirst for knowledge, but an approach to the immortal and eternal.” In other words, if for a person ancient period nature was reality, then for a medieval man it is only a symbol of deity. For medieval man, symbols were more real than the world around him.

This worldview has led to the dogma that the universe and everything in it was created by a creator for the sake of man. The harmony and beauty of nature are pre-established by God and are absolute in their immutability. This emptied science of even a hint of the idea of ​​development. If in those days they talked about development, it was as about the unfolding of what already existed, and this strengthened the roots of the idea of ​​preformation in its worst version.

On the basis of such a religious-philosophical, distorted perception of the world, a number of generalizations were made that influenced the further development of natural science. For example, the theological principle of beauty and preformation was finally overcome only by the middle of the 19th century. For approximately the same length of time, it was necessary to refute the principle “nothing is new under the moon” established in the Middle Ages, i.e. the principle of the immutability of everything that exists in the world.

In the first half of the 15th century. religious-dogmatic thinking with a symbolic-mystical perception of the world begins to be actively replaced by a rationalistic worldview based on faith in experience as the main tool of knowledge. Experimental science of modern times begins its chronology from the Renaissance (from the second half of the 15th century). During this period, the rapid formation of a metaphysical worldview began.

In the XV - XVII centuries. is being revived - all the best from the scientific and cultural heritage of antiquity. The achievements of ancient natural philosophers become role models. However, with the intensive development of trade, the search for new markets, the discovery of continents and lands, new information began to flow into the main countries of Europe that required systematization, and the method of general contemplation of natural philosophers, as well as the scholastic method of the Middle Ages, turned out to be unsuitable.

For a deeper study of natural phenomena, analysis was needed huge amount facts that needed to be classified. Thus, the need arose to dissect interconnected natural phenomena and study them separately. This determined the widespread use of the metaphysical method: nature is considered as a random accumulation of permanent objects and phenomena that exist initially and independently of each other. In this case, a misconception inevitably arises about the process of development in nature - it is identified with the process of growth. It was precisely this approach that was necessary to understand the essence of the phenomena being studied. In addition, the widespread use of the analytical method by metaphysicians accelerated and then completed the differentiation of natural science into special sciences and determined their specific objects of study.

During the metaphysical period of the development of natural science, many major generalizations were made by such researchers as Leonardo da Vinci, Copernicus, Giordano Bruno, Galileo, Kepler, F. Bacon, Descartes, Leibniz, Newton, Lomonosov, Linnaeus, Buffon, etc.

The first major attempt to bring science and philosophy closer and to substantiate new principles was made in the 16th century. English philosopher Francis Bacon (1561 - 1626), who can be considered as the founder of modern experimental science. F. Bacon called for the study of the laws of nature, knowledge of which would expand man's power over it. He opposed medieval scholasticism, considering experience, experiment, induction and analysis to be the basis of knowledge of nature. F. Bacon's opinion on the need for an inductive, experimental, analytical method was progressive, but it is not devoid of mechanistic and metaphysical elements. This was manifested in his one-sided understanding of induction and analysis, in underestimating the role of deduction, in reducing complex phenomena to the sum of their constituent primary properties, in representing movement only as movement in space, and also in recognizing a root cause external to nature. F. Bacon was the founder of empiricism in modern science.

During the metaphysical period, another principle of natural scientific knowledge of nature developed - rationalism. Special meaning The development of this direction was supported by the works of the French philosopher, physicist, mathematician and physiologist René Descartes (1596 - 1650). His views were fundamentally materialistic, but with elements that contributed to the spread of mechanistic views. According to Descartes, the single material substance from which the universe is built consists of infinitely divisible particles-corpuscles that completely fill space and are in continuous motion. However, he reduces the essence of movement only to the laws of mechanics: its quantity in the world is constant, it is eternal, and in the process of this mechanical movement, connections and interactions arise between the bodies of nature. This position of Descartes was important for scientific knowledge. Nature is a huge mechanism, and all the qualities of its constituent bodies are determined by purely quantitative differences. The formation of the world is not directed by a supernatural force applied to some purpose, but is subject to natural laws. Living organisms, according to Descartes, are also mechanisms formed according to the laws of mechanics. In the doctrine of knowledge, Descartes was an idealist, since he separated thinking from matter, isolating it into a special substance. He also exaggerated the role of the rational principle in knowledge.

Great influence on the development of natural science in the 17th - 18th centuries. influenced by the philosophy of the German idealist mathematician Gottfried Wilhelm Leibniz (1646 - 1716). Although initially adhering to mechanistic materialism, Leibniz moved away from it and created his own system objective idealism, the basis of which was his doctrine of monads. According to Leibniz, monads are simple, indivisible, spiritual substances that constitute the “elements of things” and are endowed with the capacity for activity and movement. Since the monads that form the entire world around us are absolutely independent, this introduced into Leibniz’s teaching the teleological principle of original purposefulness and harmony established by the creator.

Natural science was particularly influenced by Leibniz's idea of ​​continuum - the recognition of the absolute continuity of phenomena. This was expressed in his famous aphorism: “Nature makes no leaps.” From Leibniz's idealistic system followed preformationist ideas: in nature nothing arises anew, and everything that exists only changes due to increase or decrease, that is, development is the unfolding of what was created in advance.

Thus, the metaphysical period (XV - XVIII centuries) is characterized by the existence of various principles in the knowledge of nature. According to these principles, from the 15th to the 18th centuries inclusive, the following basic ideas arose in biology: systematization, preformationism, epigenesis and transformism. They developed within the framework discussed above philosophical systems, and at the same time this turned out to be extremely useful for the creation of an evolutionary doctrine, free from natural philosophy and idealism.

In the second half of the 17th and the beginning of the 18th century. a large amount of descriptive material had accumulated that required in-depth study. The accumulation of facts had to be systematized and generalized. It was during this period that the problem of classification was intensively developed. However, the essence of systematic generalizations was determined by the paradigm of the order of nature established by the creator. Nevertheless, bringing the chaos of facts into a system was in itself valuable and necessary.

To begin classification to create a system of plants and animals, it was necessary to find a criterion. This criterion was used to select the species. The species was first identified by the English naturalist John Ray (1627 - 1705). According to Ray, a species is the smallest collection of organisms that are identical in morphological characteristics, breeding together and producing offspring that retain this similarity. Thus, the term “species” acquires a natural scientific concept, as an unchangeable unit of living nature.

The first systems of botanists and zoologists of the 16th, 17th and 18th centuries. turned out to be artificial, that is, plants and animals were grouped according to some characteristics chosen arbitrarily. Such systems provided an ordering of facts, but usually did not reflect family ties between organisms. However, this initially limited approach played an important role in the creation of the natural system.

The pinnacle of artificial taxonomy was the system developed by the great Swedish naturalist Carl Linnaeus (1707 - 1778). He summarized the achievements of numerous predecessors and supplemented them with his own vast descriptive material. His main works “System of Nature” (1735), “Philosophy of Botany” (1735), “Species of Plants” (1753) and others are devoted to problems of classification. Linnaeus's merit is that he introduced common language(Latin), binary nomenclature and established a clear subordination (hierarchy) between systematic categories, arranging them in the following order: phylum, class, order, family, genus, species, variation. Linnaeus clarified the purely practical concept of a species as a group of individuals that does not have transitions to neighboring species, are similar to each other and reproduce the characteristics of the parent pair. He also proved conclusively that the species is the universal unit in nature, and this was an assertion of the reality of species. However, Linnaeus considered species to be immutable units. He recognized the unnaturalness of his system. However, by natural system Linnaeus did not understand the identification of family ties between organisms, but the knowledge of the order of nature established by the creator. This showed his creationism.

Linnaeus's introduction of binary nomenclature and clarification of the concept of species were of great importance for the further development of biology and gave direction to descriptive botany and zoology. Descriptions of species were now reduced to clear diagnoses, and the species themselves received specific, international names. Thus, the comparative method is finally introduced, i.e. systems are built on the basis of grouping species according to the principle of similarities and differences between them.

In the 17th and 18th centuries. A special place is occupied by the idea of ​​preformation, according to which the future organism in miniature form is already present in the germ cells. This idea was not new. It was formulated quite clearly by the ancient Greek natural philosopher Anaxagoras. However, in the 17th century. preformation was revived on a new basis in connection with the first successes of microscopy and because it strengthened the paradigm of creationism.

The first microscopists were Leeuwenhoek (1632 - 1723), Gamm (1658 - 1761), Swammerdam (1637 - 1680), Malpighi (1628 - 1694), etc. Of particular importance was the discovery by Leeuwenhoek's student - Gamm of spermatozoa (animalcules), in each of which saw an independent organism. And then the preformationists divided into two irreconcilable camps: ovists and animalculists. The first argued that all living things come from an egg, and the role of the masculine principle was reduced to the immaterial spiritualization of the embryo. Animalculists believed that future organisms are ready-made in the male principle. There was no fundamental difference between ovists and animalculists, since they were united by a common idea, which became stronger among biologists until the 19th century. Preformationists often used the term “evolution”, giving it a limited meaning, relating only to the individual development of organisms. This preformationist interpretation reduced evolution to the mechanistic, quantitative development of a pre-existing embryo.

Thus, according to the “embedding theory” proposed by the Swiss naturalist Albrecht Haller (1707 - 1777), the embryos of all generations are laid in the ovaries of the first females from the moment of their creation. At first, the individual development of organisms was explained from the position of the nesting theory, but then it was transferred to the entire organic world. This was done by the Swiss naturalist and philosopher Charles Bonnet (1720 - 1793) and was his merit, regardless of whether the problem was solved correctly. After Bonnet's work, the term evolution begins to express the idea of ​​​​preformed development of the entire organic world. Based on the idea that all future generations are embedded in the body of the primary female of a given species, Bonnet came to the conclusion that all development is predetermined. Extending this concept to the entire organic world, he creates the doctrine of the ladder of creatures, which was outlined in the work “Treatise on Nature” (1765).

Bonnet represented the ladder of beings as a pre-established (preformed) unfolding of nature from lower forms to higher ones. At the lowest levels he places inorganic bodies, followed by organic bodies (plants, animals, monkeys, humans), this ladder of beings ends with angels and God. Following the ideas of Leibniz, Bonnet believed that in nature everything “goes gradually”, there are no sharp transitions and jumps, and the ladder of creatures has as many steps as there are known species. This idea, developed by other biologists, then led to the denial of systematics. The idea of ​​gradualism forced us to look for intermediate forms, although Bonnet believed that one step of the ladder does not come from another. His ladder of creatures is static and reflects only the proximity of steps and the order of deployment of preformed rudiments. Only much later, the ladder of beings, freed from preformationism, had a positive influence on the formation of evolutionary ideas, since it demonstrated the unity of organic forms.

In the middle of the 18th century. The idea of ​​preformation was opposed to the idea of ​​epigenesis, which was expressed in a mechanistic interpretation back in the 17th century. Descartes. But this idea was presented more substantively by Caspar Friedrich Wolf (1735 - 1794). He outlined it in his main work, The Theory of Generation (1759). Wolf established that in the embryonic tissues of plants and animals there is no trace of future organs and that the latter are gradually formed from an undifferentiated embryonic mass. At the same time, he believed that the nature of the development of organs is determined by the influence of nutrition and growth, during which the previous part determines the appearance of the subsequent one.

Due to the fact that preformationists already used the terms “development” and “evolution” to denote the deployment and growth of previous rudiments, Wolf introduced the concept of “generation,” defending the actually true concept of development. Wolf could not correctly determine the reasons for development, and therefore came to the conclusion that the engine of formation is a special internal force inherent only in living matter.

The ideas of preformation and epigenesis were incompatible in those days. The first was justified from the positions of idealism and theology, and the second from the positions of mechanistic materialism. In essence, these were attempts to understand the two sides of the process of development of organisms. Only in the 20th century. managed to finally overcome the fantastic idea of ​​preformation and the mechanistic interpretation of epigenesis. And now it can be argued that in the development of organisms, preformation (in the form of genetic information) and epigenesis (shape formation based on genetic information) simultaneously take place.

At this time, a new direction in natural science emerged and rapidly developed - transformism. Transformism in biology is the doctrine of the variability of plants and animals and the transformation of some species into others. Transformism should not be considered as a direct germ of evolutionary theory. Its significance was reduced only to strengthening the ideas about the variability of living nature, the reasons for which were explained incorrectly. He is limited to the idea of ​​​​the transformation of some species into others and does not develop it to the idea of ​​\u200b\u200bthe consistent historical development of nature from simple to complex. Proponents of transformism, as a rule, did not take into account the historical continuity of changes, believing that changes can occur in any direction, without connection with previous history. Transformism also did not consider evolution as a universal phenomenon of living nature.

The most prominent representative of early transformism in biology was the French naturalist Georges Louis Leclerc Buffon (1707-1788). Buffon outlined his views in two fundamental works: “On the Ages of Nature” and in the 36-volume “Natural History”. He was the first to express a “historical” point of view regarding inanimate and living nature, and also tried to connect, albeit from the standpoint of naive transformism, the history of the Earth with the history of the organic world.

Among taxonomists of that time, the idea of ​​natural groups of organisms began to be increasingly discussed. It was impossible to solve the problem from the standpoint of the theory of creation, and transformists proposed a new point of view. For example, Buffon believed that many representatives of the fauna of the New and Old Worlds had a common origin, but then, having settled on different continents, they changed under the influence of living conditions. True, these changes were allowed only within certain limits and did not affect the organic world as a whole.

The first hole in the metaphysical worldview was made by the philosopher I. Kant (1724 - 1804). In his famous work “General Natural History and Theory of the Heavens” (1755), he rejected the idea of ​​a first shock and came to the conclusion that the Earth and the entire solar system are something that arose in time. Consequently, everything that exists on Earth was also not initially given, but arose according to natural laws in a certain sequence. However, Kant's idea was realized much later.

Geology helped us realize that nature not only exists, but is in the process of formation and development. Thus, Charles Lyell (1797 - 1875) developed the uniformitarian theory in his three-volume work “Fundamentals of Geology” (1831 - 1833). According to this theory, changes in the earth's crust occur under the influence of the same natural causes and laws. Such reasons are: climate, water, volcanic forces, organic factors. The time factor is of great importance. Under the influence of the prolonged action of natural factors, changes occur that link geological eras with transitional periods. Lyell, studying sedimentary rocks of the Tertiary period, clearly showed the continuity of the organic world. He divided the Tertiary time into three periods: Eocene, Miocene, Pliocene and established that if in the Eocene there lived special organic forms that were significantly different from modern ones, then in the Miocene there were already forms close to modern ones. Consequently, the organic world changed gradually. However, Lyell was unable to develop this idea of ​​the historical transformation of organisms further.

Gaps in metaphysical thinking were also made by other generalizations: physicists formulated the law of conservation of energy, and chemists synthesized a number of organic compounds, which united inorganic and organic nature.

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Moscow 2009

Introduction

Geological time scales

Main divisions of the geological history of the Earth

The origin and development of the evolutionary idea

Evolution of single-celled organisms

The emergence and development of multicellular organization

Evolution of the plant world

Evolution of the animal world

Human factor

Conclusion

List of used literature

Introduction

The evolutionary development of organisms is studied by a number of sciences that consider different aspects of this fundamental problem of natural science. The fossil remains of animals and plants that existed on Earth in past geological epochs are studied by paleontology, which should be placed in first place among the sciences directly related to the study of the evolution of the organic world. By studying the remains of ancient forms and comparing them with living organisms, paleontologists reconstruct the appearance, lifestyle and family relationships of extinct animals and plants, determine the time of their existence and on this basis recreate phylogeny - the historical continuity of different groups of organisms, their evolutionary history. However, in solving these complex problems, paleontology must rely on data and conclusions from many other sciences belonging to the range of biological, geological and geographical disciplines (paleontology itself, studying the fossil remains of organisms, is, as it were, at the intersection of biology and geology). To understand the living conditions of ancient organisms, determine the time of their existence and the patterns of transition of their remains into a fossil state, paleontology uses data from such sciences as historical geology, stratigraphy, paleogeography, paleoclimatology, etc. On the other hand, to analyze the structure, physiology, lifestyle and the evolution of extinct forms must be based on detailed knowledge of the relevant aspects of the organization and biology of existing organisms. Such knowledge is provided, first of all, by work in the field of comparative anatomy. One of the main tasks of comparative anatomy is to establish the homology of organs and structures in different types . Homology refers to similarity based on kinship; the presence of homologous organs proves direct family ties between the organisms possessing them (as ancestors and descendants or as descendants of common ancestors). Homologous organs consist of similar elements, develop from similar embryonic rudiments and occupy similar positions in the body. The currently developing functional anatomy, as well as comparative physiology, make it possible to approach the understanding of the functioning of organs in extinct animals. In analyzing the structure, life activity and conditions of existence of extinct organisms, scientists rely on the principle of actualism put forward by the geologist D. Getton and deeply developed by one of the largest geologists of the 19th century. -- C. Lyell. According to the principle of actualism, the patterns and relationships observed in the phenomena and objects of the inorganic and organic world in the date and time acted in the past (and hence “the present is the key to knowledge of the past”). Of course, this principle is an assumption, but it is probably true in most cases (although one must always take into account the possibility of some kind of originality in the course of certain processes in the past compared to the present). The paleontological record, represented by the fossil remains of extinct organisms, has gaps, sometimes very large, due to the specific conditions of burial of the remains of organisms and the extreme rarity of the coincidence of all the factors necessary for this. To reconstruct the phylogeny of organisms in its entirety, to reconstruct numerous “missing links” in a family tree (graphic representation of phylogeny), purely paleontological data and methods are in many cases insufficient. Here the so-called triple parallelism method comes to the rescue, introduced into science by the famous German scientist E. Haeckel and based on a comparison of paleontological, comparative anatomical and embryological data. Haeckel proceeded from the “basic biogenetic law” he formulated, which states that ontogeny (individual development of an organism) is a compressed and abbreviated repetition of phylogeny. Consequently, the study of the individual development of modern organisms makes it possible, to some extent, to judge the course of evolutionary transformations of their distant ancestors, including those not preserved in the fossil record. Later A.N. Severtsov, in his theory of phylembryogenesis, showed that the relationship between ontogenesis and phylogeny is much more complex than E. believed. Haeckel. In reality, it is not phylogeny that creates individual development (new evolutionary acquisitions lengthen ontogenesis, adding new stages), as Haeckel believed, but, on the contrary, hereditary changes in the course of ontogenesis lead to evolutionary rearrangements (“phylogeny is the evolution of ontogenesis”). Only in some special cases, when the evolutionary restructuring of an organ occurs through changes in the later stages of its individual development, i.e., new characteristics are formed at the end of ontogenesis (Severtsov called this method of evolutionary restructuring of ontogenesis anabolia), is such a relationship between ontogenesis and phylogeny, which is described by Haeckel’s biogenetic law. Only in these cases can embryological data be used to analyze phylogeny. A.N. himself Severtsov gave interesting examples of the reconstruction of hypothetical “missing links” in the phylogenetic tree. The study of the ontogenies of modern organisms has another, no less important significance for the analysis of the course of phylogeny: it makes it possible to find out which changes in ontogenesis, “creating evolution,” are possible and which are not, which provides the key to understanding specific evolutionary rearrangements. To understand the essence of the evolutionary process, for a causal analysis of the course of phylogenesis, the conclusions of evolutionary science - a science also called the theory of evolution or Darwinism, named after the great creator of the theory of natural selection, Charles Darwin - are of paramount importance. Evolutionary science, which studies the essence, mechanisms, general patterns and directions of the evolutionary process, is the theoretical basis of all modern biology. In fact, the evolution of organisms is a form of existence of living matter in time, and all modern manifestations of life, at any level of organization of living matter, can be understood only taking into account evolutionary prehistory. All the more important are the basic principles of the theory of evolution for the study of the phylogeny of organisms. The listed sciences by no means exhaust the list of scientific disciplines involved in the study and analysis of the development of life on Earth in past geological eras. To understand the species identity of fossil remains and transformations of species of organisms over time, the conclusions of taxonomy are extremely important; to analyze the change of faunas and floras in the geological past - biogeographic data. A special place is occupied by questions of the origin of man and the evolution of his closest ancestors, which has some specific features compared to the evolution of other higher animals, due to the development of labor activity and sociality.

Geological time scales

When studying the evolution of organisms, it is necessary to have an idea of ​​its course over time, the duration of certain stages. The historical sequence of formation of sedimentary rocks, i.e. relative age, in this area is established relatively simply: rocks that arose later were deposited on top of earlier layers. The correspondence of the relative age of sedimentary rock layers in different regions can be determined by comparing the fossil organisms preserved in them (a paleontological method, the foundations of which were laid at the end of the 18th century - early XIX V. works of the English geologist W. Smith). Usually, among the fossil organisms characteristic of each era, it is possible to identify several of the most common, numerous and widespread species; such species are called leading fossils. As a rule, the absolute age of sedimentary rocks, i.e., the period of time that has passed since their formation, cannot be directly determined. Information for determining absolute age is contained in igneous (volcanic) rocks, which arise from cooling magma. The absolute age of igneous rocks can be determined by the content of radioactive elements and their decay products. Radioactive decay begins in igneous rocks from the moment they crystallize from magma melts and continues at a constant rate until all reserves of radioactive elements are exhausted. Therefore, by determining the content of a particular radioactive element and its decay products in a rock and knowing the decay rate, it is possible to calculate the absolute age of a given rock quite accurately (with the possibility of an error of about 5%). For sedimentary rocks one has to take an approximate age in relation to the absolute age of the volcanic rock layers. A long and painstaking study of the relative and absolute ages of rocks in different regions of the globe, which required the hard work of several generations of geologists and paleontologists, made it possible to outline the main milestones in the geological history of the Earth. The boundaries between these divisions correspond to various kinds of changes of a geological and biological (paleontological) nature. These may be changes in the sedimentation regime in water bodies, leading to the formation of other types of sedimentary rocks, increased volcanism and mountain-building processes, sea invasion (marine transgression) due to the subsidence of large areas of the continental crust or rising ocean levels, significant changes in fauna and flora. Since such events have occurred irregularly in Earth's history, the duration different eras, periods and eras are different. Noteworthy is the enormous duration of the most ancient geological eras (Archaeozoic and Proterozoic), which, moreover, are not divided into smaller time intervals (in any case, there is no generally accepted division). This is primarily due to the time factor itself - the antiquity of the Archeozoic and Proterozoic deposits, which during their long history underwent significant metamorphism and destruction, erasing the once existing milestones of the development of the Earth and life. The deposits of the Archaeoic and Proterozoic eras contain extremely few fossil remains of organisms; on this basis, the Archaeozoic and Proterozoic are combined under the name “cryptozoic” (the stage of hidden life) in contrast to the unification of the three subsequent eras - the “Phanerozoic” (the stage of obvious, observable life). The age of the Earth is determined by different scientists in different ways, but we can point to an approximate figure of 5 billion years.

Development of life in the cryptozoic

The eras belonging to the Cryptozoic - Archaeozoic and Proterozoic - together lasted more than 3.4 billion years; three eras of the Phanerozoic - 570 million years, i.e. the cryptozoic accounts for at least 7/8 of all geological history. However, extremely few fossil remains of organisms have been preserved in cryptozoic sediments, so scientists' ideas about the first stages of the development of life during these huge periods of time are largely hypothetical.

Cryptozoan deposits

The oldest remains of organisms were found in the sedimentary strata of Rhodesia, which are 2.9--3.2 billion years old. Traces of the vital activity of algae (probably blue-green) were found there, which convincingly indicates that about 3 billion years ago photosynthetic organisms - algae - already existed on Earth. Obviously, the appearance of life on Earth should have occurred much earlier than -- maybe 3.5 -- 4 billion years ago. The most famous is the Middle Proterozoic flora (filamentous forms up to several hundred micrometers long and 0.6-16 microns thick, having different structures, unicellular microorganisms (Fig. 1), with a diameter of 1-16 microns, also of different structures), the remains of which were discovered In Canada -- in siliceous shales on the northern shore of Lake Superior. The age of these deposits is about 1.9 billion years.

In sedimentary rocks formed between 2 and 1 billion years ago, stromatolites are often found, which indicates the widespread and active photosynthetic and reef-building activity of blue-green algae during this period.

The next most important milestone in the evolution of life is documented by a number of finds of fossil remains in sediments with an age of 0.9-1.3 billion years, among which the remains of unicellular organisms measuring 8-12 microns in size were found in excellent preservation, in which it was possible to distinguish the intracellular structure, similar to the core; Stages of division of one of the species of these single-celled organisms were also discovered, reminiscent of the stages of mitosis - a method of dividing eukaryotic (i.e., having a nucleus) cells.

If the interpretation of the described fossil remains is correct, this means that about 1.6-1.35 billion years ago the evolution of organisms passed a major milestone - the level of eukaryotic organization was reached.

The first traces of the life activity of worm-like multicellular animals are known from Late Riphean deposits. In Vendian times (650-570 million years ago) there were already a variety of animals, probably belonging to different types. A few prints of soft-bodied Vendian animals are known from different regions of the globe. A number of interesting finds were made in Late Proterozoic deposits on the territory of the USSR.

The most famous is the rich Late Proterozoic fossil fauna discovered by R. Sprigg in 1947 in Central Australia. M. Glessner, who studied this unique fauna, believes that it includes about three dozen species of very diverse multicellular animals belonging to different types (Fig. 2). Most forms probably belong to the coelenterates. These are jellyfish-like organisms, probably “hovering” in the water column, and polypoid forms attached to the seabed, solitary or colonial, reminiscent of modern alcyonarians, or sea feathers. It's great that all of them, like other animals of the Ediacaran fauna lack a hard skeleton.

In addition to coelenterates, the Pound quartzites, which host the Ediacaran fauna, contain remains of worm-like animals classified as flatworms and annelids. Several species of organisms are interpreted as possible ancestors of arthropods. Finally, there are a number of fossil remains of unknown taxonomic affiliation. This indicates a huge distribution of the fauna of multicellular soft-bodied animals in Vendian times,

Since the Vendian fauna is so diverse and includes quite highly organized animals, it is obvious that evolution had already been going on for quite a long time before its emergence. Probably, multicellular animals appeared much earlier - somewhere in the range of 700-900 million years ago.

Sharp increase in fossil richness

The boundary between the Proterozoic and Paleozoic eras (i.e., between the Cryptozoic and Phanerozoic) is marked by a striking change in the composition and richness of fossil fauna. Suddenly (there’s probably no other word for it) after the strata of the Upper Proterozoic, almost devoid of traces of life, in the sedimentary rocks of the Cambrian (the first period of the Paleozoic era), starting from the lowest horizons, a huge variety and abundance of remains of fossil organisms appear. Among them are the remains of sponges, brachiopods, mollusks, representatives of the extinct type of archaeocyaths, arthropods and other groups. By the end of the Cambrian, almost all known types of multicellular animals appeared. This sudden “explosion of morphogenesis” at the border of the Proterozoic and Paleozoic is one of the most mysterious, still completely unsolved, events in the history of life on Earth. Thanks to this, the beginning of the Cambrian period is such a noticeable milestone that often the entire previous time in geological history (i.e., the entire cryptozoic) is called the “Precambrian.”

Probably, the separation of all the main types of animals occurred in the Upper Proterozoic, in the period of 600-800 million years ago. The primitive representatives of all groups of multicellular animals were small, skeletal-free organisms. The continued accumulation of oxygen in the atmosphere and the increase in the power of the ozone screen towards the end of the Proterozoic allowed animals, as indicated above, to increase body size and acquire a skeleton. Organisms were able to spread widely at shallow depths in various bodies of water, which led to a significant increase in the diversity of life forms.

The origin and development of the evolutionary idea

The first glimpses of evolutionary thought arose in the depths of the dialectical natural philosophy of ancient times, which viewed the world in endless movement, constant self-renewal on the basis of the universal connection and interaction of phenomena and the struggle of opposites.

The exponent of the spontaneous dialectical view of nature was Heraclitus, an Ephesian thinker (about 530-470 BC) who said that in nature everything flows, everything changes as a result of the mutual transformations of the primary elements of the cosmos - fire, water, air, earth, contained in embryo the idea of ​​a universal development of matter that has no beginning or end.

Representatives of mechanistic materialism were philosophers of a later period (460-370 BC). According to Democritus, the world consisted of countless indivisible atoms located in infinite space. Atoms are in a constant process of random connection and separation, in random motion, and vary in size, mass and shape; bodies resulting from the accumulation of atoms can also be different. The lighter ones rose up and formed fire and sky, the heavier ones, descending, formed water and earth, in which various living beings were born: fish, land animals, birds.

The ancient Greek philosopher Empedocles (490-430 BC) was the first to try to interpret the mechanism of the origin of living beings. Developing Heraclitus's thought about the primary elements, he argued that their mixing creates many combinations, some of which - the least successful - are destroyed, while others - harmonious combinations - are preserved. Combinations of these elements create animal organs. The connection of organs with each other gives rise to complete organisms. Remarkable was the idea that only viable options out of many unsuccessful combinations survived in nature.

The origin of biology as a science is associated with the activities of the great thinker from Greece, Aristotle (387-322 BC). In his works, he outlined the principles of classification of animals, compared various animals according to their structure, and laid the foundations of ancient embryology. He drew attention to the fact that in different organisms, embryogenesis (embryo development) passes through a sequential series: first, the most general characteristics are laid down, then species-specific and, finally, individual ones. Having discovered the great similarity of the initial stages in embryogenesis of representatives of different groups of animals, Aristotle came to the idea of ​​​​the possibility of the unity of their origin. With this conclusion, Aristotle anticipated the ideas of embryonic similarity and epigenesis (embryonic neoplasms), put forward and experimentally substantiated in the middle of the 18th century.

The subsequent period, up to the 16th century, gave almost nothing to the development of evolutionary thought. During the Renaissance, interest in ancient science sharply increased and the accumulation of knowledge began, which played a significant role in the formation of the evolutionary idea.

The exceptional merit of Darwin's teaching was that it gave a scientific, materialistic explanation for the emergence of higher animals and plants through the consistent development of the living world, and that it used the historical method of research to solve biological problems. However, even after Darwin, many natural scientists retained the same metaphysical approach to the very problem of the origin of life. Widespread in the scientific circles of America and Western Europe, Mendelism-Morganism put forward the position that heredity and all other properties of life are possessed by particles of a special gene substance concentrated in the chromosomes of the cell nucleus. These particles seem to have suddenly appeared on Earth at some point and have retained their life-defining structure largely unchanged throughout the development of life. Thus, the problem of the origin of life, from the point of view of the Mendelian-Morganists, comes down to the question of how a particle of gene substance endowed with all the properties of life could suddenly arise.

Life as a special form of existence of matter is characterized by two distinctive properties - self-reproduction and exchange of substances with the environment. All modern hypotheses of the origin of life are based on the properties of self-reproduction and metabolism. The most widely accepted hypotheses are coacervate and genetic.

Coacervate hypothesis. In 1924 A.I. Oparin first formulated the main provisions of the concept of prebiological evolution and then, based on the experiments of Bungenberg de Jong, developed these provisions in the coacervate hypothesis of the origin of life. The basis of the hypothesis is the statement that initial stages biogenesis were associated with the formation of protein structures.

The first protein structures (protobionts, in Oparin’s terminology) appeared during the period when protein molecules were delimited from the environment by a membrane. These structures could arise from the primary “broth” due to coacervation—the spontaneous separation of an aqueous solution of polymers into phases with different concentrations. The coacervation process resulted in the formation of microscopic droplets with a high concentration of polymers. Some of these droplets absorbed low molecular weight compounds from the environment: amino acids, glucose, primitive catalysts. The interaction of the molecular substrate and catalysts already meant the emergence of the simplest metabolism within protobionts.

The metabolic droplets incorporated new compounds from the environment and increased in volume. When the coacervates reached the maximum size allowed under the given physical conditions, they broke up into smaller droplets, for example, under the action of waves, as happens when shaking a vessel containing an oil-in-water emulsion. The small droplets continued to grow again and then form new generations of coacervates.

The gradual complication of protobionts was carried out by the selection of such coacervate drops, which had the advantage of better utilization of the matter and energy of the environment. Selection as the main reason for the improvement of coacervates into primary living beings is the central position in Oparin’s hypothesis.

Genetic hypothesis. According to this hypothesis, nucleic acids first emerged as the matrix basis for protein synthesis. It was first put forward in 1929 by G. Möller.

It has been experimentally proven that simple nucleic acids can replicate without enzymes. Protein synthesis on ribosomes occurs with the participation of transport (t-RNA) and ribosomal RNA (r-RNA). They are capable of building not just random combinations of amino acids, but ordered polymers of proteins. Perhaps the primary ribosomes consisted only of RNA. Such protein-free ribosomes could synthesize ordered peptides with the participation of tRNA molecules that bound to rRNA through base pairing.

At the next stage chemical evolution matrices appeared that determined the sequence of t-RNA molecules, and thereby the sequence of amino acids that are bound by t-RNA molecules.

The ability of nucleic acids to serve as templates in the formation of complementary chains (for example, the synthesis of mRNA on DNA) is the most convincing argument in favor of the idea of ​​​​the leading importance in the process of biogenesis of the hereditary apparatus and, consequently, in favor of the genetic hypothesis of the origin of life.

Main stages of biogenesis. The process of biogenesis included three main stages: the emergence of organic substances, the appearance of complex polymers (nucleic acids, proteins, polysaccharides), and the formation of primary living organisms.

First stage -- the emergence of organic substances. Already during the formation of the Earth, a significant reserve of abiogenic organic compounds was formed. The starting materials for their synthesis were gaseous products of the pre-oxygen atmosphere and hydrosphere (CH4, CO2, H2O, H2, NH3, NO2). It is these products that are used in the artificial synthesis of organic compounds that form the biochemical basis of life.

Experimental synthesis of protein components - amino acids in attempts to create living things “in vitro” began with the work of S. Miller (1951-1957). S. Miller conducted a series of experiments on the effects of spark electric discharges on a mixture of gases CH4, NH3, H2 and water vapor, as a result of which he discovered the amino acids asparagine, glycine, and glutamine. The data obtained by Miller was confirmed by Soviet and foreign scientists.

Along with the synthesis of protein components, nucleic components—purine and pyrimidine bases and sugars—were experimentally synthesized. By moderately heating a mixture of hydrogen cyanide, ammonia and water, D. Oro obtained adenine. He also synthesized uracil by reacting an ammonia solution of urea with compounds arising from simple gases under the influence of electrical discharges. From a mixture of methane, ammonia and water under the influence of ionizing radiation, the carbohydrate components of nucleotides - ribose and deoxyribose - were formed. Experiments using ultraviolet irradiation have shown the possibility of synthesizing nucleotides from a mixture of purine bases, ribose or deoxyribose and polyphosphates. Nucleotides are known to be monomers of nucleic acids.

Second phase -- formation of complex polymers. This stage of the origin of life was characterized by the abiogenic synthesis of polymers like nucleic acids and proteins.

S. Akabyuri was the first to synthesize polymers of protoproteins with a random arrangement of amino acid residues. Then, on a piece of volcanic lava, by heating a mixture of amino acids to 100°C, S. Focke obtained a polymer with a molecular weight of up to 10,000, containing all the amino acids typical of proteins included in the experiment. Focke called this polymer a proteinoid.

Artificially created proteinoids were characterized by properties inherent in the proteins of modern organisms: a repeating sequence of amino acid residues in the primary structure and noticeable enzymatic activity.

Polymers of nucleotides, similar to the nucleic acids of organisms, have been synthesized in laboratory conditions that cannot be reproduced in nature. G. Kornberg showed the possibility of synthesizing nucleic acids in vitro; this required specific enzymes that could not be present under the conditions of the primitive Earth.

In the initial processes of biogenesis, chemical selection is of great importance, which is a factor in the synthesis of simple and complex compounds. One of the prerequisites for chemical synthesis is the ability of atoms and molecules to selectivity during their interactions in reactions. For example, chlorine halogen or inorganic acids prefer to combine with light metals. The property of selectivity determines the ability of molecules to self-assemble, which was shown by S. Fox. Complex macromolecules are characterized by strict ordering, both in the number of monomers and in their spatial arrangement.

The ability of macromolecules to self-assemble A.I. Oparin considered as proof of the position he put forward that the protein molecules of coacervates could be synthesized without a matrix code.

Third stage -- the appearance of primary living organisms. From simple carbon compounds, chemical evolution led to highly polymeric molecules that formed the basis for the formation of primitive living beings. The transition from chemical evolution to biological evolution was characterized by the emergence of new qualities that were absent at the chemical level of development of matter. The main ones were the internal organization of protobionts, adapted to the environment thanks to a stable metabolism and energy, and the inheritance of this organization based on the replication of the genetic apparatus (matrix code).

A.I. Oparin and his colleagues showed that coacervates have a stable metabolism with the environment. Under certain conditions, concentrated aqueous solutions of polypeptides, polysaccharides and RNA form coacervate droplets with a volume of 10 -7 to 10 -6 cm 3, which have an interface with the aqueous medium. These droplets have the ability to assimilate substances from the environment and synthesize new compounds from them.

Thus, coacervates containing the enzyme glycogen phosphorylase absorbed glucose-1-phosphate from solution and synthesized a polymer similar to starch.

Self-organizing structures similar to coacervates were described by S. Fauquet and called them microspheres. When heated, concentrated solutions of proteinoids were cooled, spherical droplets with a diameter of about 2 μm spontaneously appeared. At certain pH values ​​of the medium, the microspheres formed a two-layer shell, reminiscent of the membranes of ordinary cells. They also had the ability to divide by budding.

Although microspheres do not contain nucleic acids and lack pronounced metabolism, they are considered as a possible model for the first self-organizing structures reminiscent of primitive cells.

Cells - the basic elementary unit of life, capable of reproduction, all the main metabolic processes take place in it (biosynthesis, energy metabolism, etc.). Therefore, the emergence of cellular organization meant the emergence of true life and the beginning of biological evolution.

Evolution of single-celled organisms

Until the 1950s, it was not possible to detect traces of Precambrian life at the level of single-celled organisms, since the microscopic remains of these creatures cannot be detected by conventional paleontological methods. An important role in their discovery was played by a discovery made at the beginning of the 20th century. C. Walcott. In Precambrian deposits in western North America, he found layered pillar-shaped limestone formations, later called stromatolites. In 1954, it was discovered that the stromatolites of the Gunflint Formation (Canada) were formed by the remains of bacteria and blue-green algae. Living stromatolites have also been discovered off the coast of Australia, consisting of the same organisms and very similar to fossil Precambrian stromatolites. To date, the remains of microorganisms have been found in dozens of stromatolites, as well as in clayey shales of sea coasts.

The earliest of bacteria (prokaryotes) existed already about 3.5 billion years ago. To date, two families of bacteria have been preserved: ancient, or archaeobacteria (halophilic, methane, thermophilic), and eubacteria (all others). Thus, the only living creatures on Earth for 3 billion years were primitive microorganisms. Perhaps they were single-celled creatures similar to modern bacteria, such as clostridia, living on the basis of fermentation and the use of energy-rich organic compounds that arise abiogenically under the influence of electrical discharges and ultraviolet rays. Consequently, in this era, living beings were consumers of organic substances, and not their producers.

A giant step on the path of the evolution of life was associated with the emergence of basic biochemical metabolic processes - photosynthesis And breathing and with the formation of a cellular organization containing the nuclear apparatus (eukaryotes). These “inventions,” made in the early stages of biological evolution, have been largely preserved in modern organisms. Using the methods of molecular biology, a striking uniformity of the biochemical foundations of life has been established, with a huge difference between organisms in other characteristics. The proteins of almost all living things are made up of 20 amino acids. Nucleic acids that encode proteins are assembled from four nucleotides. Protein biosynthesis is carried out according to a uniform pattern; the site of their synthesis is ribosomes; mRNA and tRNA are involved in it. The vast majority of organisms use the energy of oxidation, respiration and glycolysis, which is stored in ATP.

Let us consider in more detail the features of evolution at the cellular level of life organization. The greatest difference exists not between plants, fungi and animals, but between organisms that have a nucleus (eukaryotes) and those that do not (prokaryotes). The latter are represented by lower organisms - bacteria and blue-green algae (cyanobacteria, or cyanea), all other organisms are eukaryotes, which are similar to each other in intracellular organization, genetics, biochemistry and metabolism.

The difference between prokaryotes and eukaryotes also lies in the fact that the former can live both in oxygen-free (obligate anaerobes) and in environments with different oxygen contents (facultative anaerobes and aerobes), while for eukaryotes, with few exceptions, it is obligatory oxygen. All these differences were essential for understanding the early stages of biological evolution.

A comparison of prokaryotes and eukaryotes in terms of oxygen demand leads to the conclusion that prokaryotes arose during a period when the oxygen content in the environment changed. By the time eukaryotes appeared, oxygen concentrations were high and relatively constant.

The first photosynthetic organisms appeared about 3 billion years ago. These were anaerobic bacteria, the predecessors of modern photosynthetic bacteria. It is assumed that they formed the oldest known stromatolites. The depletion of the environment in nitrogenous organic compounds caused the emergence of living creatures capable of using atmospheric nitrogen. Such organisms, capable of existing in an environment completely devoid of organic carbon and nitrogen compounds, are photosynthetic nitrogen-fixing blue-green algae. These organisms carried out aerobic photosynthesis. They are resistant to the oxygen they produce and can use it for their own metabolism. Since blue-green algae arose during a period when the concentration of oxygen in the atmosphere fluctuated, it is quite possible that they are intermediate organisms between anaerobes and aerobes.

It is assumed that photosynthesis, in which the source of hydrogen atoms for the reduction of carbon dioxide is hydrogen sulfide (which photosynthesis is carried out by modern green and purple sulfur bacteria), preceded the more complex two-stage photosynthesis, in which hydrogen atoms are extracted from water molecules. The second type of photosynthesis is characteristic of cyanides and green plants.

The photosynthetic activity of primordial unicellular organisms had three consequences that had a decisive influence on the entire further evolution of living things. Firstly, photosynthesis freed organisms from competition for natural reserves of abiogenic organic compounds, the amount of which in the environment had significantly decreased. The autotrophic nutrition that developed through photosynthesis and the storage of ready-made nutrients in plant tissues then created the conditions for the emergence of a huge variety of autotrophic and heterotrophic organisms. Secondly, photosynthesis ensured the saturation of the atmosphere with a sufficient amount of oxygen for the emergence and development of organisms whose energy metabolism is based on respiration processes. Thirdly, as a result of photosynthesis, an ozone shield was formed in the upper part of the atmosphere, protecting earthly life from the harmful ultraviolet radiation of space,

Another significant difference between prokaryotes and eukaryotes is that in the latter the central metabolic mechanism is respiration, while in most prokaryotes energy metabolism is carried out in fermentation processes. Comparison of the metabolism of prokaryotes and eukaryotes leads to the conclusion about the evolutionary relationship between them. Anaerobic fermentation probably arose at earlier stages of evolution. After the appearance of a sufficient amount of free oxygen in the atmosphere, aerobic metabolism turned out to be much more profitable, since the oxidation of carbohydrates increases the yield of biologically useful energy by 18 times compared to fermentation. Thus, anaerobic metabolism was joined by the aerobic method of extracting energy by single-celled organisms.

When did eukaryotic cells appear? There is no exact answer to this question, but a significant amount of data on fossil eukaryotes suggests that their age is about 1.5 billion years. There are two hypotheses regarding how eukaryotes arose.

One of them (autogenic hypothesis) suggests that the eukaryotic cell arose by differentiation of the original prokaryotic cell. First, a membrane complex developed: an outer cell membrane was formed with invaginations into the cell, from which separate structures were formed that gave rise to cellular organelles. It is impossible to say from which particular group of prokaryotes arose eukaryotes.

Another hypothesis (symbiotic) was proposed by the American scientist Margulis. She based it on new discoveries, in particular the discovery of extranuclear DNA in plastids and mitochondria and the ability of these organelles to divide independently. L. Margulis suggests that the eukaryotic cell arose as a result of several acts of symbiogenesis. First, a large amoeboid prokaryotic cell united with small aerobic bacteria, which turned into mitochondria. This symbiotic prokaryotic cell then incorporated spirochete-like bacteria, which formed kinetosomes, centrosomes, and flagella. After the isolation of the nucleus in the cytoplasm (a characteristic of eukaryotes), the cell with this set of organelles turned out to be the starting point for the formation of the kingdoms of fungi and animals. The combination of a prokaryotic cell with cyanides led to the formation of a plastid cell, which gave

the beginning of the formation of the plant kingdom. Margulis's hypothesis is not shared by everyone and has been criticized. Most authors adhere to the autogenic hypothesis, which is more consistent with the Darwinian principles of monophyly, differentiation and complication of organization in the course of progressive evolution.

In the evolution of a unicellular organization, intermediate steps are distinguished, associated with the complication of the structure of the organism, the improvement of the genetic apparatus and methods of reproduction.

The most primitive stage is agamic prokaryotic -- represented by cyanides and bacteria. The morphology of these organisms is the simplest in comparison with other single-celled (protozoa). However, already at this stage differentiation into cytoplasm, nuclear elements, basal granules, and cytoplasmic membrane appears. Bacteria are known to exchange genetic material through conjugation. A wide variety of bacterial species and the ability to exist in a wide variety of environmental conditions indicate the high adaptability of their organization.

Next stage -- agamic eukaryotic -- characterized by further differentiation of the internal structure with the formation of highly specialized organelles (membranes, nucleus, cytoplasm, ribosomes, mitochondria, etc.). Particularly significant here was the evolution of the nuclear apparatus - the formation of real chromosomes in comparison with prokaryotes, in which the hereditary substance is diffusely distributed throughout the cell. This stage is characteristic of protozoa, the progressive evolution of which followed the path of increasing the number of identical organelles (polymerization), increasing the number of chromosomes in the nucleus (polyploidization), and the appearance of generative and vegetative nuclei - macronucleus and micronucleus (nuclear dualism). Among unicellular eukaryotic organisms, there are many species with agamous reproduction (naked amoebas, shell rhizomes, flagellates).

A progressive phenomenon in the phylogenesis of protozoa was the emergence of sexual reproduction (gamogony), which differs from ordinary conjugation. Protozoa have meiosis with two divisions and crossing over at the chromatid level, and gametes with a haploid set of chromosomes are formed. In some flagellates, gametes are almost indistinguishable from asexual individuals and there is still no division into male and female gametes, i.e., isogamy is observed. Gradually, in the course of progressive evolution, a transition occurs from isogamy to anisogamy, or the division of generative cells into female and male, and to anisogamous copulation. When gametes fuse, a diploid zygote is formed. Consequently, in protozoa there has been a transition from the agamic eukaryotic stage to the zygotic stage - the initial stage of xenogamy (reproduction by cross-fertilization). The subsequent development of multicellular organisms followed the path of improving methods of xenogamous reproduction.

The emergence and development of multicellular organization

The next stage of evolution after the emergence of unicellular organisms was the formation and progressive development of a multicellular organism. This stage is distinguished by the great complexity of the transitional stages, of which colonial unicellular, primary differentiated, centrally differentiated are distinguished.

Colonial unicellular the stage is considered transitional from a unicellular organism to a multicellular one and is the simplest of all stages in the evolution of multicellular organization.

Recently, the most primitive forms of colonial unicellular organisms have been discovered, standing as it were halfway between unicellular organisms and lower multicellular organisms (sponges and coelenterates). They were allocated to the subkingdom Mesozoa, but in the evolution of multicellular organization, representatives of this half-kingdom are considered dead-end lines. When deciding the origin of multicellularity, greater preference is given to colonial flagellates (Gonium, Pandorina, Volvox). Thus, a Gonium colony consists of 16 united flagellate cells, but without any specialization of their functions as members of the colony, i.e., it is a mechanical conglomerate of cells.

Primary differentiated A stage in the evolution of a multicellular organization is characterized by the beginning of specialization according to the principle of “division of labor” among members of the colony. Elements of primary specialization are observed in the colonies of Pandorina morum (16 cells), Eudorina elegans (32 cells), Volvox globator (thousands of cells). Specialization in these organisms comes down to the division of cells into somatic cells, which carry out the functions of nutrition and movement (flagella), and generative cells (gonidia), which serve for reproduction. There is also pronounced anisogamy here. At the primary differentiated stage, specialization of functions occurs at the tissue, organ and systemic organ level. Thus, coelenterates have already formed a simple nervous system, which, by distributing impulses, coordinates the activity of motor, glandular, stinging, and reproductive cells. There is no nerve center as such yet, but there is a coordination center.

Development begins with coelenterates centrally differentiated stages in the evolution of multicellular organization. At this stage, the complication of the morphophysiological structure occurs through increased tissue specialization, starting with the emergence of germ layers that determine the morphogenesis of the nutritional, excretory, generative and other organ systems. A well-defined centralized nervous system arises: in invertebrates - gangliolar, in vertebrates - with central and peripheral sections. At the same time, methods of sexual reproduction are being improved - from external to internal fertilization, from free incubation of eggs outside the mother's body to viviparity.

The finale in the evolution of the multicellular organization of animals was the appearance of organisms with “intelligent type” behavior. This includes animals with highly developed conditioned reflex activity, capable of transmitting information to the next generation not only through heredity, but also in a supragametic way (for example, transferring experience to young animals through training). The final stage in the evolution of the centrally differentiated stage was the emergence of man.

Let us consider the main stages of the evolution of multicellular organisms in the sequence as it occurred in the geological history of the Earth. All multicellular organisms are divided into three kingdoms: fungi (Fungi), plants (Metaphyta) and animals (Metazoa). Very little is known about the evolution of fungi, since their fossil record remains scarce. The other two kingdoms are much richer in fossil remains, making it possible to reconstruct the course of their history in some detail.

Evolution of the plant world

In the Proterozoic era (about 1 billion years ago), the evolutionary trunk of the most ancient eukaryotes was divided into several branches, from which multicellular plants (green, brown and red algae), as well as fungi, arose. Most of the primary plants floated freely in sea ​​water(diatoms, golden algae), some of them were attached to the bottom.

An essential condition for the further evolution of plants was the formation of a soil substrate on the land surface as a result of the interaction of bacteria and cyanide with minerals and under the influence of climatic factors. At the end of the Silurian period, soil-forming processes prepared the possibility of plants reaching land (440 million years ago). Among the plants that were the first to colonize land were psilophytes.

Other groups of terrestrial vascular plants arose from psilophytes: mosses, horsetails, ferns, which reproduce by spores and prefer an aquatic environment. Primitive communities of these plants spread widely in the Devonian. During the same period, the first gymnosperms appeared, arising from ancient ferns and inheriting their tree-like appearance. The transition to propagation by seeds had a great advantage, since it freed the sexual process from the need for an aquatic environment (as is also observed in modern ferns).

The evolution of higher land plants followed the path of increasing reduction of the haploid generation (gametophyte) and the predominance of the diploid generation (sporophyte).

The flourishing of gymnosperms, in particular conifers, which began in the Permian period, led to their dominance in the Mesozoic era. By the middle of the Permian period, the climate became drier, which was largely reflected in changes in the composition of the flora. Giant ferns, tree-like mosses, and calamites disappeared from the arena of life, and the color of the tropical forests, so bright for that era, gradually disappeared.

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The first glimpses of evolutionary thought arose in the depths of the dialectical natural philosophy of ancient times, which viewed the world in endless movement, constant self-renewal on the basis of the universal connection and interaction of phenomena and the struggle of opposites. The exponent of the spontaneous dialectical view of nature was Heraclides, an Ephesian thinker (about 530-470 BC) who said that in nature everything flows, everything changes as a result of the mutual transformations of the primary elements of the cosmos - fire, water, air, earth, contained in embryo the idea of ​​a universal development of matter that has no beginning or end. The views of the largest representatives of the Ionian school of philosophers: 1) Thales of Miletus believed that everything arose from the primary material - water in the course of natural development. 2) Anaximander proceeded from the fact that life arose from water and earth under the influence of heat. 3) According to Anaximenes, the main element is air, capable of being rarefied and condensed, and by this process Anaximenes explained the reason for the differences in substances. He argued that man and animal originated from earthly mucus. Representatives of mechanistic materialism were philosophers of a later period (460-370 BC). According to Democritus, the world consisted of countless indivisible atoms located in infinite space. Atoms are in a constant process of random connection and separation. Atoms are in random motion and are different in size, mass and shape, then the bodies that appear as a result of the accumulation of atoms can also be different. The lighter ones rose up and formed fire and sky, the heavier ones, descending, formed water and earth, in which various living beings were born: fish, land animals, birds. The ancient Greek philosopher Empedocles (490-430 BC) was the first to try to interpret the mechanism of the origin of living beings. Developing Heraclides' thought about the primary elements, he argued that their mixing creates many combinations, some of which - the least successful - are destroyed, while others - harmonious combinations - are preserved. Combinations of these elements create animal organs. The connection of organs with each other gives rise to complete organisms. Remarkable was the idea that only viable options out of many unsuccessful combinations survived in nature. The origin of biology as a science is associated with the activities of the great thinker from Greece, Aristotle (387-322 BC). In his major works, he outlined the principles of classification of animals, compared various animals according to their structure, and laid the foundations of ancient embryology. The work “On the Parts of Animals” presents the idea of ​​the interconnection (correlation) of organs, that a change in one organ entails a change in another, connected with it by functional relationships. In his work “The Origin of Animals,” Aristotle developed a comparative anatomical method and applied it in embryological studies. He drew attention to the fact that in different organisms embryogenesis (embryo development) passes through a sequential series: at the beginning the most general characteristics are laid down, then species-specific and, finally, individual. Having discovered the great similarity of the initial stages in embryogenesis of representatives of different groups of animals, Aristotle came to the idea of ​​​​the possibility of the unity of their origin. With this conclusion, Aristotle anticipated the ideas of embryonic similarity and epigenesis (embryonic neoplasms), put forward and experimentally substantiated in the middle of the 18th century. Thus, the views of ancient philosophers contained a number of important elements evolutionism: firstly, the idea of ​​the natural emergence of living beings and their changes as a result of the struggle of opposites and the survival of successful options, secondly, the idea of ​​​​stepwise complication of the organization of living nature; thirdly, the idea of ​​the integrity of the organism (the principle of correlation) and of embryogenesis as a process of neoplasm. Noting the importance of ancient thinkers in the development of philosophy, F. Engels wrote: “...in the diverse forms of Greek philosophy, almost all later types of worldviews are already in embryo, and in the process of emergence.” The subsequent period, up to the 16th century, gave almost nothing to the development of evolutionary thought. During the Renaissance, interest in ancient science sharply increased and the accumulation of knowledge began, which played a significant role in the formation of the evolutionary idea. The exceptional merit of Darwin's teaching was that it gave a scientific, materialistic explanation for the emergence of higher animals and plants through the consistent development of the living world, and that it used the historical method of research to solve biological problems. However, even after Darwin, many natural scientists retained the same metaphysical approach to the very problem of the origin of life. Widespread in the scientific circles of America and Western Europe, Mendelism-Morganism put forward the position that heredity and all other properties of life are possessed by particles of a special gene substance concentrated in the chromosomes of the cell nucleus. These particles seem to have suddenly appeared on Earth at some point and have retained their life-defining structure largely unchanged throughout the development of life. Thus, the problem of the origin of life, from the point of view of the Mendelian-Morganists, comes down to the question of how a particle of gene substance endowed with all the properties of life could suddenly arise. Most foreign authors speaking on this issue (for example, Devillier in France or Alexander in America) approach it in a very simplified manner. In their opinion, the gene molecule arises purely by chance, thanks to the “lucky” combination of carbon, hydrogen, oxygen, nitrogen and phosphorus atoms, which “by themselves” formed into an extremely complex molecule of gene substance, which immediately received all the attributes of life. But this kind of “happy accident” is so exceptional and unusual that it could supposedly happen only once during the existence of the Earth. Subsequently, there was only constant reproduction of this once-arising, eternal and unchangeable gene substance. This “explanation”, of course, does not explain anything in essence. A characteristic feature of all living beings without exception is that their internal organization is extremely well, completely adapted to the implementation of certain life phenomena: nutrition, respiration, growth and reproduction in given conditions of existence. How could this internal adaptability, which is so characteristic of all, even the simplest living forms, arise as a result of pure chance? By anti-scientifically denying the regularity of the process of the origin of life, considering this most important event in the life of our planet as accidental, supporters of these views cannot answer this question and inevitably slide into the most idealistic, mystical ideas about the primary creative will of the deity and about a specific plan for the creation of life. Thus, in Schrödinger’s recently published book “What is Life from the Point of View of Physics”, in the book of the American biologist Alexander “Life, Its Nature and Origin” and in a number of other works by bourgeois authors we find a direct statement that life could only arise as a result of creative the will of the deity. Mendelism-Morganism is trying to ideologically disarm biologists in their fight against idealism. He seeks to prove that the question of the origin of life - this most important ideological problem - is insoluble from a materialistic point of view. However, this kind of statement is completely false. It is easily refuted if we approach the question that interests us from the position of the only correct, truly scientific philosophy - from the position of dialectical materialism. Life as a special form of existence of matter is characterized by two distinctive properties - self-reproduction and exchange of substances with the environment. All modern hypotheses of the origin of life are based on the properties of self-reproduction and metabolism. The most widely accepted hypotheses are coacervate and genetic. Coacervate hypothesis. In 1924, A. I. Oparin first formulated the main provisions of the concept of prebiological evolution and then, based on the experiments of Bungenberg de Jong, developed these provisions in the coacervate hypothesis of the origin of life. The basis of the hypothesis is the statement that the initial stages of biogenesis were associated with the formation of protein structures. The first protein structures (protobionts, in Oparin’s terminology) appeared during the period when protein molecules were delimited from the environment by a membrane. These structures could arise from the primary “broth” due to coacervation - the spontaneous separation of an aqueous solution of polymers into phases with different concentrations. The coacervation process resulted in the formation of microscopic droplets with a high concentration of polymers. Some of these droplets absorbed low molecular weight compounds from the environment: amino acids, glucose, primitive catalysts. The interaction of the molecular substrate and catalysts already meant the emergence of the simplest metabolism within protobionts. The metabolic droplets incorporated new compounds from the environment and increased in volume. When the coacervates reached the maximum size allowed under the given physical conditions, they broke up into smaller droplets, for example, under the action of waves, as happens when shaking a vessel containing an oil-in-water emulsion. The small droplets continued to grow again and then form new generations of coacervates. The gradual complication of protobionts was carried out by the selection of such coacervate drops, which had the advantage of better utilization of the matter and energy of the environment. Selection as the main reason for the improvement of coacervates into primary living beings is a central position in Oparin's hypothesis. Genetic hypothesis. According to this hypothesis, nucleic acids first emerged as the matrix basis for protein synthesis. It was first put forward in 1929 by G. Möller. It has been experimentally proven that simple nucleic acids can replicate without enzymes. Protein synthesis on ribosomes occurs with the participation of transport (t-RNA) and ribosomal RNA (r-RNA). They are capable of building not just random combinations of amino acids, but ordered polymers of proteins. Perhaps the primary ribosomes consisted only of RNA. Such protein-free ribosomes could synthesize ordered peptides with the participation of tRNA molecules that bound to rRNA through base pairing. At the next stage of chemical evolution, matrices appeared that determined the sequence of t-RNA molecules, and thereby the sequence of amino acids that are bound by t-RNA molecules. The ability of nucleic acids to serve as templates in the formation of complementary chains (for example, the synthesis of mRNA on DNA) is the most convincing argument in favor of the idea of ​​​​the leading importance in the process of biogenesis of the hereditary apparatus and, consequently, in favor of the genetic hypothesis of the origin of life. Main stages of biogenesis. The process of biogenesis included three main stages: the emergence of organic substances, the appearance of complex polymers (nucleic acids, proteins, polysaccharides), and the formation of primary living organisms. The first stage is the emergence of organic substances. Already during the formation of the Earth, a significant reserve of abiogenic organic compounds was formed. The starting materials for their synthesis were gaseous products of the pre-oxygen atmosphere and hydrosphere (CH4, CO2, H2O, H2, NH3, NO2). It is these products that are used in the artificial synthesis of organic compounds that form the biochemical basis of life. Experimental synthesis of protein components - amino acids in attempts to create living things “in vitro” began with the work of S. Miller (1951-1957). S. Miller conducted a series of experiments on the effects of spark electric discharges on a mixture of gases CH4, NH3, H2 and water vapor, as a result of which he discovered the amino acids asparagine, glycine, and glutamine. The data obtained by Miller was confirmed by Soviet and foreign scientists. Along with the synthesis of protein components, nucleic components - purine and pyrimidine bases and sugars - were experimentally synthesized. By moderately heating a mixture of hydrogen cyanide, ammonia and water, D. Oro obtained adenine. He also synthesized uracil by reacting an ammonia solution of urea with compounds arising from simple gases under the influence of electrical discharges. From a mixture of methane, ammonia and water under the influence of ionizing radiation, the carbohydrate components of nucleotides - ribose and deoxyribose - were formed. Experiments using ultraviolet irradiation have shown the possibility of synthesizing nucleotides from a mixture of purine bases, ribose or deoxyribose and polyphosphates. Nucleotides are known to be monomers of nucleic acids. The second stage is the formation of complex polymers. This stage of the origin of life was characterized by the abiogenic synthesis of polymers like nucleic acids and proteins. S. Akabyuri was the first to synthesize polymers of protoproteins with a random arrangement of amino acid residues. Then, on a piece of volcanic lava, when a mixture of amino acids was heated to 100°C, Focke obtained a polymer with a molecular weight of up to 10,000, containing all the amino acids typical of proteins included in the experiment. Fock called this polymer a proteinoid. Artificially created proteinoids were characterized by properties inherent in the proteins of modern organisms: a repeating sequence of amino acid residues in the primary structure and noticeable enzymatic activity. Polymers of nucleotides, similar to the nucleic acids of organisms, have been synthesized in laboratory conditions that cannot be reproduced in nature. G. Kornberg showed the possibility of synthesizing nucleic acids in vitro; this required specific enzymes that could not be present under the conditions of the primitive Earth. In the initial processes of biogenesis, chemical selection is of great importance, which is a factor in the synthesis of simple and complex compounds. One of the prerequisites for chemical synthesis is the ability of atoms and molecules to be selective in their interactions in reactions. For example, chlorine halogen or inorganic acids prefer to combine with light metals. The property of selectivity determines the ability of molecules to self-assemble, which was shown by S. Fox. Complex macromolecules are characterized by strict ordering, both in the number of monomers and in their spatial arrangement. A. I. Oparin considered the ability of macromolecules to self-assemble as evidence of his thesis that protein molecules of coacervates could be synthesized without a matrix code. The third stage is the appearance of primary living organisms. From simple carbon compounds, chemical evolution led to highly polymeric molecules that formed the basis for the formation of primitive living beings. The transition from chemical evolution to biological evolution was characterized by the emergence of new qualities that were absent at the chemical level of development of matter. The main ones were the internal organization of protobionts, adapted to the environment thanks to a stable metabolism and energy, and the inheritance of this organization based on the replication of the genetic apparatus (matrix code). A.I. Oparin and his colleagues showed that coacervates have a stable metabolism with the environment. Under certain conditions, concentrated aqueous solutions of polypeptides, polysaccharides and RNA form coacervate droplets with a volume of 10-7 to 10-6 cm3, which have an interface with the aqueous medium. These droplets have the ability to assimilate substances from the environment and synthesize new compounds from them. Thus, coacervates containing the enzyme glucogen phosphorylase absorbed glucose-1-phosphate from solution and synthesized a polymer similar to starch. Self-organizing structures similar to coacervates were described by S. Fauquet and called them microspheres. When heated, concentrated solutions of proteinoids were cooled, spherical droplets with a diameter of about 2 μm spontaneously appeared. At certain pH values ​​of the medium, the microspheres formed a two-layer shell, reminiscent of the membranes of ordinary cells. They also had the ability to divide by budding. Although microspheres do not contain nucleic acids and lack pronounced metabolism, they are considered as a possible model for the first self-organizing structures reminiscent of primitive cells. Cells are the basic elementary unit of life, capable of reproduction; all major metabolic processes (biosynthesis, energy metabolism, etc.) take place in it. Therefore, the emergence of cellular organization meant the emergence of true life and the beginning of biological evolution.

The stage of origin and formation of evolutionary ideas - from the beginning of the 30s. XIX century until the end of the 19th - beginning of the 20th centuries.

Already from the end of the 18th century. in the natural sciences (including physics, which came to the fore), facts and empirical material accumulated that did not “fit” into the mechanical picture of the world and were not explained by it.

The “undermining” of this picture of the world came mainly from two sides: firstly, from the side of physics itself and, secondly, from the side of geology and biology.

In physics, research in the field of electric and magnetic fields has intensified. A particularly great contribution to this research was made by the English scientists M. Faraday (1791-1867) and D. Maxwell (1831-1879). Thanks to their efforts, not only corpuscular, but also continuum (“continuous medium”) representations began to form.

Faraday discovered the relationship between electricity and magnetism, introduced the concepts of electric and magnetic fields, and put forward the idea of ​​​​the existence of an electromagnetic field. Maxwell created electrodynamics and statistical physics, built a theory of the electromagnetic field, predicted the existence of electromagnetic waves, and put forward the idea of ​​​​the electromagnetic nature of light. Thus, matter appeared not only as a substance (as in the mechanical picture of the world), but also as an electromagnetic field.

It should be noted that, in contrast to classical mechanics, which used the principle of long-range action, here, in electrodynamics, the theory is based on the principle of short-range action, according to which energy is transferred from point to point with a finite speed. In the works of M. Faraday, and then D. C. Maxwell, the role of such an energy carrier was assigned to the electromagnetic field.

The successes of electrodynamics led to the creation of an electromagnetic picture of the world, which explained a wider range of phenomena and more deeply expressed the unity of the world, since electricity and magnetism were explained on the basis of the same laws (the laws of Ampere, Ohm, Biot-Savart-Laplace, etc.). Since electromagnetic processes were not reduced to mechanical ones, the conviction began to form that the basic laws of the universe are not the laws of mechanics, but the laws of electrodynamics. The mechanistic approach to such phenomena as light, electricity, magnetism was not successful, and electrodynamics increasingly replaced mechanics.

As for the second direction of change in the mechanical picture of the world, its beginning is associated with the names of the English geologist C. Lyell (1797-1875) and the French biologists J. B. Lamarck (1744-1829) and J. Cuvier (1769-1832).

Charles Lyell, in his main work “Fundamentals of Geology” (1830-1833), developed the doctrine of slow and continuous changes in the earth’s surface under the influence of constant geological factors. Charles Lyell is one of the founders of the actualistic method in natural science, the essence of which is that, based on knowledge of the present, conclusions are drawn about the past (i.e., the present is the key to the past). However, the Earth for Lyell does not develop in a specific direction, it simply changes in a random, incoherent way. Moreover, for him, change is only gradual quantitative changes, without a jump, without breaks of gradualness, without qualitative changes. And this is a metaphysical, “flat-evolutionary” approach.

J.B. Lamarck created the first holistic concept of the evolution of living nature. In his opinion, species of animals and plants are constantly changing, becoming more complex in their organization as a result of the influence of the external environment and a certain internal desire of all organisms for improvement. Having proclaimed the principle of evolution as a universal law of the development of living nature, Lamarck, however, did not reveal the true reasons for evolutionary development.

Unlike Lamarck, J. Cuvier did not recognize the variability of species, explaining the change in fossil faunas with the so-called “catastrophe theory,” which excluded the idea of ​​evolution of the organic world. Cuvier argued that each period in the history of the Earth ends with a global catastrophe - the rise and fall of continents, floods, ruptures of layers, etc. As a result of these catastrophes, animals and plants died, and in new conditions new species appeared, not similar to the previous ones. He did not indicate or explain the cause of the disasters.

So, already in the first decades of the 19th century. the “overthrow” of the generally metaphysical way of thinking that dominated natural science was actually prepared. Three great discoveries especially contributed to this: the creation of the cellular theory, the discovery of the law of conservation and transformation of energy, and Darwin’s development of the evolutionary theory.

The cell theory was created by German scientists M. Schleiden and T. Schwann in 1838-1839. Cell theory proved the internal unity of all living things and pointed to the unity of origin and development of all living beings. She established a common origin, as well as the unity of structure and development of plants and animals.

Opened in the 40s. XIX century the law of conservation and transformation of energy (J. Mayer, D. Joule, E. Lenz) showed that the so-called “forces” that were previously recognized as isolated - heat, light, electricity, magnetism, etc. - are interconnected, and under certain conditions pass into one to another and represent only different forms of the same movement in nature. Energy, as a general quantitative measure of various forms of motion of matter, does not arise from nothing and will not disappear, but can only pass from one form to another.

Charles Darwin's theory was finally formalized in his main work, “The Origin of Species by Means of Natural Selection” (1859). This theory showed that plant and animal organisms (including humans) were not created by God, but are the result of a long natural development (evolution) of the organic world, originating from a few simple creatures, which in turn originated from inanimate nature. Thus, the material factors and causes of evolution were found - heredity and variability - and the driving factors of evolution - natural selection for organisms living in the “wild” nature, and artificial selection for domestic animals and cultivated plants bred by humans.

Subsequently, Darwin's theory was confirmed by genetics, showing the mechanism of changes on the basis of which the theory of natural selection is able to work. In the middle of the 20th century, especially in connection with the discovery of the structure of DNA in 1953 by F. Crick and J. Watson, the so-called systematic theory of evolution was formed, combining classical Darwinism and the achievements of genetics. 3

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