Biology (from the Greek. Bios — life, logos — learning) —the totality of the sciences of living nature. The term biology was proposed by J. Lamarck at the end of the 18th century. Biology is a very extensive science so that one researcher can cover it.

Therefore, most biologists are specialists in any one of its branches: botany or zology, anatomy or physiology, histology or embryology, parasitology, ecology, evolutionary theory, genetics, etc. Despite the many-sided nature of biology, there are There are some generalizations, such as cellular theory (M. Schleiden, 1838; T. Schwann, 1839), the theory of evolution of the organic world (the main provisions of which were formed by C. Darwin, 1859), the laws of heredity (G. Mendel, 1865 ) and others. Prepared by the whole course of the previous developed Ia sciences, they determine their future and form the foundation of subsequent research in various fields of natural science.

Theory of the evolution of the organic world

The formation of biology is closely connected with the formation of ideas about the historical development of the organic world. Elements of this idea are traced in the works of ancient Greek philosophers from Thales to Aristotle. Many philosophers and naturalists of the Renaissance and the new time expressed the idea of ​​the variability of living nature. Among them is the German philosopher G. Leibniz, who predicted the existence of transitional forms between plants and animals; Swiss naturalist S. Bonnet, who developed the idea of ​​the "ladder of beings" (1745) as a reflection of the progressive complication of the organic world; L. L. Buffon, who put forward a bold hypothesis about the development of the Earth (1749). By dividing Earth’s “natural history” into seven periods, Buffon suggested that plants, then animals, and behind them man also appeared in the last periods of the planet’s development. He also admitted that some forms can be transformed into others under the influence of climate or conditions of existence, and that there is a "continuous hierarchy from the lowest plant to the most highly organized animal."

A huge influence on the formation of the evolutionary ideas of scientists of several generations had the principles of systematics of the organic world, which laid the Swedish physician and naturalist Karl Linnaeus (Linnaeus, Sago-lus, 1707-1778). In his famous work "The System of Nature" ("Systema naturae", 1735), 12 times published during the author's life, the basics of the classification of the "three kingdoms of nature" (plants, animals and minerals) were first proposed. He divided each of the kingdoms into classes, detachments, clans, and species; for all organic species introduced a mandatory binary (dual) nomenclature. For the first time, Linnee carried man to the class of mammals (primate detachment), which at that time required a great civil courage from a scientist. C. Linney was elected a member of the Academies of Sciences of Germany (1754), Sweden (1739), Great Britain (1753), Russia (1754), France (1762). This testifies to its enormous influence on the development of world natural science.

The works of Linnaeus contributed to the formation of the ideas of J. Lamarck and C. Darwin.

The first theory of the evolutionary development of living beings was formulated by the French natural scientist Jean Lamarck (Lamarck, Jean Baptiste Pierre Antoine de Monet, 1744–1829), a disciple and follower of French materialists and enlighteners of the 18th century. (Fig. 116).

Lamarck's evolutionary theory was a natural-philosophical concept with elements of idealism. The basic tenets of his theory set forth in the work Philosophy of Zoology (Philo-sophie zoologique, 1809), Lamarck derived by studying the comparative anatomy of invertebrates (he was the first to divide animals into vertebrates and invertebrates and introduced these concepts). Lamarck argued that there are no sharp edges between species; the species are not permanent - they change, acquiring new properties under the influence of the environment, and inherit these traits. He opposed the concept of preformism, arguing that “all living bodies originate from one another”, but at the same time they do not develop from “pre-existing embryos”. Lamarck's theory contained several provisions of an idealistic character. Lamarck believed that the signs arising adequately influencing environmental factors, are inherited. In addition, he explained the progress of organisms by their internal “striving” for self-improvement.

These provisions later formed the basis of Lamarckism, a unilateral concept of the second half of the 19th century, which became the antithesis of Darwinism after the death of Lamarck. But all this does not detract from the historical merit of Lamarck himself, who proposed the first holistic theory of evolution. This was understood and highly appreciated by one of the greatest biologists of the world, the founder of evolutionary theory - Charles Darwin (Darwin, Charles Robert, 1809-1828; fig. 117). Charles Darwin left a great scientific heritage, which has more than 8 thousand printed pages. His basic work, “The Origin of Species by Natural Selection, or the Preservation of Selected Breeds in the Struggle for Life” (“The Origin of Species”) was published in 1859. In the subsequent works of C. Darwin, “The Change of Pets and cultivated plants "(1868)," The origin of man and sexual selection "(1871) and other evolutionary doctrine received its further development.

Based on a huge amount of factual material, which was largely obtained during a round-the-world voyage on the Beagle (1831–1836), undertaken by him after graduating from the University of Cambridge, Charles Darwin argued that animals and plants existing on Earth originated from previously distributed species as a result of evolution. The main factors of evolution of Charles Darwin determined variability, heredity and natural selection in the conditions of the “struggle for existence” (the concept introduced by Darwin). Thus, Charles Darwin gave a materialistic (dialectical) rationale for the emergence of adaptive features as opposed to the idealist '(metaphysical) point of view about the initial expediency of the existing world.

F '. Engels called Darwin’s theory. among the three main natural discoveries. XIX century. In a letter to Karl Marx, he wrote in 1859: "... so far, there has never been such a grandiose attempt to prove historical development in nature, and, moreover, with such success." Charles Darwin was elected an honorary doctor of the Cambridge, Bonn, Breslav and Leiden universities, corresponding member of the Petersburg (1867) and Berlin (1878) academies of sciences. His teachings opened a new historical approach to the study of the laws of living nature and contributed to the further development of all biological sciences.

The doctrine of heredity and variability

A serious scientific substantiation of evolutionary theory was the discovery of the laws of heredity by Czech naturalist Gregor Mendel (Mendel Gregor Johann, 1822–1884, Fig. 118), who became the founder of one of the most important areas of modern biology — genetics (from Greek genetikos — referring to origin; the term suggested Bateson (V. Bateson) in 1906). In experiments on the hybridization of two varieties of peas, which Mendel spent for 10 years, he found that organisms contain hereditary factors that are transmitted to offspring when crossed, are of a discrete nature and pass from generation to generation according to variation-static laws (1865). The basic principles of the theory of heredity were set out in his work Experiments on Plant Hybrids (Versuche tiber Pflanzen-Hybriden, 1865), which later became classical.

G. Mendel was ahead of the science of his time. His discovery did not receive an adequate assessment and for a long time remained in the shadows. It was not known to H, Darwin, while it was “Mendelism ... that eliminates the most dangerous objection that, according to Darwin himself, his theories have ever been made” *. This is the loss of newly acquired traits in the generations. Recognition of the revolutionary role of Mendel's discovery took place in 1900/1901, when G. de Fries (G. de Fries, Holland), K. Correns (S. Sogrens, Germany) and E. Chermak (E. Tschermak, Austria) almost simultaneously reopened the laws of heredity of Mendel and empirically proved the correctness of his conclusions. Since that time, experimental genetics has begun - the science of the heredity and variability of organisms.

An important stage in the development of genetics was the creation in 1911 of the chromosomal theory of heredity (T Morgan (T. Morgan) and co-workers). From this point on, the material theory of the gene became the leading theory of genetics. The twentieth century was the time of the rapid development of genetics, and on its basis of new directions, molecular genetics and molecular biology.