The first attempts to classify flowering plants, as well as the plant world in general, were based on a few, arbitrarily taken, easily conspicuous external signs. These were purely artificial classifications, in which plants that were often very systematically distant found themselves in the same group. Beginning with the first artificial system by the Italian botanist Andrea Cesalpino (1583), several artificial classifications of the plant kingdom, including flowering plants, have been proposed. The crowning achievement of the period of artificial classifications was the famous “ reproductive system"by the great Swedish naturalist Carl Linnaeus (1735). The classification by Line was based on the number of stamens, the methods of their fusion, as well as the distribution of unisexual flowers. He shared everything seed plants(flowering and gymnosperms) into 23 classes, and included algae, fungi, mosses and ferns in the 24th class. Due to the extreme artificiality of Linnaeus's classification, genera of the most diverse families fell into the same class. orders, and, on the other hand, genera of undoubtedly natural families, for example cereals, often found themselves in different classes. Despite this artificiality, Linnaeus’ system was very convenient in practical terms, as it made it possible to quickly determine the genus and species of a plant, making it accessible not only to specialists, but also to amateurs of botany. At the same time, Liney improved and approved binomial (binary) nomenclature in botany and zoology, that is, the designation of plants and animals with a double name - by genus and species. This made Linnaeus' system even more convenient to use.

A turning point in the development of taxonomy of flowering plants was the book of the French naturalist Michel Adanson, Plant Families (1703-1764). He considered it necessary to use the maximum possible number of different characteristics to classify plants, giving equal importance to all characteristics. But also higher value for the taxonomy of flowering plants there was a book by the French botanist Aituan Laurent Jussier (1789), entitled “Genera of Plants Arranged According to Natural Order.” He divided plants into 15 classes, within which he distinguished 100 “natural orders.” Jussier gave them descriptions and names, most of which have survived to this day in the rank of families. He grouped mushrooms, algae, mosses, ferns, and naiads under the name Acolylodones. Family plants(without naiads) he divided into monocotyledons (Monocotyledonoa) and dicotyledons (Dicotyledonos), including conifers among the latter.

In the 19th century highest value had the system of the Swiss botanist Augustin Pyramus de Candolle (1813, 1819). He began to publish a review of all known species of flowering plants, which he called “Prodromus of the natural system of the plant kingdom” (from the Greek prodrornos - forerunner). This most important publication in the history of plant taxonomy began to be published in 1824 and was completed by his son Alphonse in 1874. Many botanists continued to develop de Candolle’s system, making more or less significant changes to it. The logical conclusion of all these studies was the system of the English botanists George Bentham and Joseph Hooker, published by them in the major publication “Genera of Plants” (Genera pluutarum) in 1862-1883. This was a significantly improved version of the de Candolle system. Although Bentham and Hooker's system appeared after Charles Darwin's Origin of Species, and both supported Darwin's ideas, the system itself was based on pre-Darwinian ideas about species.

The beginnings of evolutionary, or phylogenetic, taxonomy of plants existed even before Darwin's revolution in biology. But the development of phylogenetic (genealogical) systematics actually began only after the publication of “The Origin of Species.” Darwin argued that “all true classification is genealogical.” He believed that depending on "the extent of the changes undergone different groups» in the process of evolution, they are located according to different kinds, families, orders, classes, etc., and the system itself is “a genealogical distribution of creatures, as in a family tree.” Later, in his book on the origin of man (1874), Darwin wrote that every system “should be, as far as possible, genealogical in its classification, that is, the descendants of the same form should be grouped together, as distinguished from the any other form; but if the parent forms are related, the offspring will also be related, and the two groups when united will form a larger group.” Thus, he equated "kinship" (a term used in a different sense by the authors of "natural" systems) with evolutionary relationships, and systematic groups with the branches and twigs of a family tree. He considered the system of hierarchical relationships between taxa of different categories to be the result of evolution, which was a fundamentally new approach to taxonomy and its tasks.

In the 19th century There were many attempts to construct a system of flowering plants by botanists who accepted the doctrine of evolution. The systems created by a number of German botanists became especially widely known, among whom A. Engler’s system was especially widely known and recognized. However, a significant drawback of all these systems was the confusion of two concepts - simplicity and primitiveness. What was not taken into account was the fact that the simple structure of a flower, for example the structure of a casuarina, oak or willow flower, may not be primary, but secondary. The importance of reduction and secondary simplification was ignored, which, as we already know, was of great importance in the evolution of the flower, especially in anemophilous plants. Therefore, these systems, including Engler’s system, cannot be called phylogenetic.

Back in 1875, the famous German botanist and natural philosopher Alexander Braun put forward some fundamental ideas that anticipated the basic principles of the phylogenetic systematics of flowering plants by several decades. He came to the conclusion about the primitiveness of flowers of the magnolia and related families and the secondary nature of petalless and unisexual flowers, which his contemporaries, and earlier he himself, considered primitive. He considered the simplicity of these flowers to be secondary, the result of simplification. Brown has an aphorism: “In nature, as in art, the simple can be the most perfect.” Thus, Brown clearly understood that there are two types of simplicity of structure: primary simplicity, such as we see in truly ancient, primitive forms, and secondary simplicity, achieved as a result of simplification, as in the casuarina flower. However, Brown died soon (in 1877) without implementing the reform of the flowering plant system based on the principles he formulated. Similar ideas were also expressed by the German botanist Karl Wilhelm Naegeli (1884) and the French paleobotanist Gaston de Saporta (1885). But both of these outstanding botanists were not taxonomists and did not set out to construct an evolutionary system of flowering plants. The honor of reforming the classification of flowering plants on a new basis belongs to the American botanist Charles Bessey and the German botanist Hans Hallier. Their first works on the flowering plant system appeared in 1893 (Bessie) and 1903 (Hallir), but most full review Hallir's system was published in 1912, and Bessey's in 1915.

In the first half of the 20th century. appeared whole line new systems of flowering plants built on the principles formulated by Bessey and Hallier. Among these systems, mention should be made of the system of Petrograd University professor Christopher Gobi (1916) and the system of the English botanist John Hutchinson (1926, 1934). In the second half of the 20th century. systems of A. L. Takhtadzhyan (1966, 1970, 1978), American botanists Arthur Cronquist (1968) and Robert Thorne (1968, 1976), Danish botanist Rolf Dahlgren (1975, 1977) and a number of other systems appeared.

The modern classification of flowering plants is based on a synthesis of data from a variety of disciplines, primarily data from comparative morphology, including the morphology and anatomy of reproductive and vegetative organs, embryology, palynology, organellography and cytology. Along with the use of classical methods of plant morphology, electron microscopes, both scanning and transmission, are being increasingly used every day, which makes it possible to look at the ultrastructure of many tissues and cells, including pollen grains. As a result, the possibilities of comparative morphological research have expanded endlessly, which, in turn, has enriched the systematics with valuable factual material for constructing an evolutionary classification. In particular, the comparative study of cellular organelles is beginning to acquire great importance, for example, the study of the ultrastructure of plastids in the protoplast of sieve elements (the work of H. D. Banke). Methods of modern biochemistry, especially the chemistry of proteins and nucleic acids, are also becoming increasingly important. Serological methods are beginning to be widely used. Finally, the use of mathematical methods and especially computer technology is also expanding.

Division of flowering plants, or magnoliophytes, is divided into two classes: Magnoliopsids, or dicotyledons(Magnoliopsida, or Dicotyledones), and liliopsids, or monocots(Liliopsida, or Monocotyledones). The main differences between them are shown in the table.

As is clearly seen from this table, there is not a single characteristic that would serve as a sharp distinction between the two classes of flowering plants. These classes differ, in essence, only in the combination of characteristics. They have not yet diverged so much in the process of evolution that it is possible to distinguish them by one particular characteristic. Nevertheless, taxonomists, as a rule, easily establish that a particular plant belongs to one of these classes. Difficulties are caused only by the nymphaean and related families (united in the order Nympliaeales), which occupy an intermediate position in a number of respects between dicotyledons and monocotyledons.

Monocots evolved from dicots and probably branched off from them at the dawn of the evolution of flowering plants. The presence among monocots of a number of families with an apocarpous gynoecium and monocolpate pollen grains of many of their representatives suggests that monocots could only originate from dicotyledons that were characterized by these characters. Among modern dicotyledons, the largest number of characters common to those of monocotyledons are possessed by representatives of the order nymphaeans. However, all representatives of this order are specialized aquatic plants in many respects and therefore cannot be considered as probable ancestors of monocots. But their common origin is very likely. There is every reason to assume that monocots and the nymphaean order have a common origin from some more primitive terrestrial herbaceous dicotyledons.

The closest ancestors of monocots were most likely land plants, adapted to constant or temporary humidity. According to J. Byus (1927), early monocots were swamp plants or forest edge plants. J.L. Stebbins (1974) suggests that the first monocots appeared in a humid environment, along the banks of rivers and lakes. The primary monocots were probably perennial rhizomatous herbs with entire elliptical leaves with arcuate venation and avascular vascular bundles scattered along the cross section of the stem with a residual intrafascicular cambium. The flowers were in apical inflorescences, 3-membered, with a perianth in two circles, with an androecium of primitive ribbon-like stamens and an apocarpous gynoecium of primitive conduplicate carpels. The pollen grains were single-collaborated and bicellular in the mature state. The seeds had abundant endosperm.

In terms of the number of species, as well as genera and families, monocots are much inferior to dicotyledons. Nevertheless, the role of monocots in nature is extremely large, especially in herbaceous communities. Many important crop plants, including cereals and sugar cane, are monocots.

The classes of dicotyledons and monocotyledons are in turn subdivided into subclasses, which are divided into orders (sometimes combined into superorders), families, genera and species, with all intermediate categories (Fig. 50).

CLASS OF DICOTONS, which includes about 325 families, about 10,000 genera and up to 180,000 species, is divided into 7 subclasses.

The magnoliidae subclass includes the most primitive orders of dicotyledons, including magnolia, star anise, laurel and nymphaceae. Although among the members of the subclass there is no living form that combines all the primitive characters, magnolias as a whole represent the group that stands closest to the hypothetical original group that gave rise to living flowering plants.

Subclass 2. Ranunculids(Ranunculidac). Close to the magnoliid subclass, but more advanced. Mostly grass. All representatives have blood vessels. Secretory cells are usually absent in parenchymal tissues (with the exception of moonsperms). Stomata different types, in most cases without side cells. Flowers are bisexual or unisexual, often spiral or spirocyclic. Mature pollen is mostly 2-celled. The shell of pollen grains is tricolpate or a derivative of the tricolpate type, but is never monocolpate. The ovules are usually bitegmal and crassinucellate or, less commonly, tenuinucellate. Seeds most often have a small embryo and mostly with abundant endosperm, rarely without endosperm.

The ranunculid subclass includes the order Ranunculaceae and orders close to it. In all likelihood, ranunculids descend directly from magnoliids, most likely from star anise-type ancestors.

Subclass 3. Gamamelidids(Hamamelididae). Mostly woody plants with vessels (with the exception of the order Trochodendra). Stomata with 2 or more side cells or no side cells. The flowers are in most cases anemophilous, more or less reduced, mostly unisexual; the perianth is usually poorly developed, and the flowers are usually petalous and often also without a calyx. Mature pollen is mostly 2-celled, tricolpate or a derivative of the tricolpate type. The gynoecium is usually coenocarpous. The ovules are often bitegmal and in most cases crassinucellate. The fruits are mostly single-seeded. Seeds with abundant or scanty endosperm or no endosperm at all.

The subclass of Hamamelididae includes the orders Trochodendronaceae, Hamameliaceae, Nettleaceae, Beechaceae and orders close to them. Hamamelidids probably evolved directly from magnoliids.

Subclass 4. Caryophyllides(Caryophyllidae). Usually herbaceous plants, subshrubs or low shrubs, rarely small trees. The leaves are whole. Vessels are always present, vessel segments with simple perforation. Stomata with 2 or 3 (rarely 4) side cells or no side cells. The flowers are bisexual or rarely unisexual, mostly petalless. Mature pollen is usually 3-celled. The shell of pollen grains is tricolpate or a derivative of the tricolpate type. The gynoecium is apocarpous or more often coenocarpous. The ovules are usually bitegmal, crassinucellate. The seeds mostly have a bent peripheral embryo, usually with a perisperm.

The subclass Caryophyllidae includes the orders Cloveaceae, Buckwheataceae and Plumbagaceae. Caryophyllides probably evolved from primitive ranunculids.

Subclass 5. Dillienids(Dilleniidae). Trees, shrubs or grasses. The leaves are whole or variously dissected. Stomata of various types, mostly without subsidiary cells. Vessels are always present; segments of vessels with scalariform or simple perforation. The flowers are bisexual or unisexual, with a double perianth or, less often, petalless; in more primitive families the perianth is often spiral or spirocyclic. The androecium, when it consists of many stamens, develops in a centrifugal sequence. Mature pollen is 2-celled or less often 3-celled. The shell of pollen grains is tricolpate or a derivative of the tricolpate type. The gynoecium is apocarpous or more often coenocarpous. The ovules are usually bitegmal and mostly crassinucellate. Seeds usually have endosperm.

The subclass includes the orders Dilleniidae, Teacup, Violetaceae, Malvaceae, Heather, Primrose, Euphorbiaceae, etc. In all likelihood, the Dilleniidae descended from some ancient magnoliids.

Subclass 6. Rosides(Rosidae). Trees, shrubs or grasses. The leaves are whole or variously dissected. Stomata of different types, most often without side cells or with 2 side cells. Vessels are always present, vessel segments with scalariform or more often with simple perforation. The flowers are mostly bisexual, with a double perianth or petalless. The androecium, when it consists of many stamens, develops in a centripetal sequence. Mature pollen is usually 2-celled. The shell of pollen grains is tricolpate or a derivative of the tricolpate type. The gynoecium is apocarpous or coenocarpous. The ovules are usually bitegmal and crassinucellate. Seeds with or without endosperm.

The subclass of rosids includes the orders of Saxifragaceae, Roseaceae, Legumeaceae, Proteaceae, Myrtleaceae, Rutaceae, Sapindaaceae, Geraniumaceae, Dogwood, Araliaceae, Buckthornaceae, Santalaceaceae, and others. Rosidae probably originated from the closest ancestors of the Dilleniidae.

Subclass 7. Asterids(Asteridae). Trees, shrubs, or more often grasses. The leaves are whole or variously dissected. Stomata mostly with 2, 4 (often) or 6 (rarely) subsidiary cells. Vessels are always present, vessel segments with scalariform or more often with simple perforation. The flowers are usually bisexual, almost always fused-petaled. Stamens, as a rule, are in equal or smaller numbers with the corolla lobes. Mature pollen is 3-celled or 2-celled. The shell of pollen grains is tricolpate or a derivative of the tricolpate type. The gynoecium is always coenocarpous, apparently morphologically always paracarpous, usually consisting of 2-5, rarely 6-14 carpels. The ovules are always unitegmal, tenuinucellate, or rarely crassinucellate. Seeds with or without endosperm.

The extensive subclass of asterids includes the orders Teassaceae, Gentianaceae, Norichaceae, Lamiaceae, Campanaceae, Asteraceae, etc. In all likelihood, asterids originate from primitive rosids, most likely from some ancient forms close to modern woody representatives of the order Saxifragaceae.

CLASS MONOCOTONS, containing about 65 families, about 3,000 genera and at least 60,000 species, is divided into 3 subclasses.

Subclass 1. Alismatids(Alismatidae). Aquatic or marsh herbs. Stomata with 2 or less often 4 subsidiary cells. Vessels are absent or present only in the roots. Flowers are bisexual or unisexual. The perianth is developed or reduced, often absent. Mature pollen is usually 3-celled. The shell of pollen grains is single-porous, bi-porous, multi-porous or non-aperturate. The gynoecium is mostly apocarpous, less often coenocarpous. The ovules are bitegmal, crassinucellate or rente tenuinucellate. The endosperm is nuclear or helobial. Seeds without endosperm.

The subclass of Alismatidae includes the orders of Chastukhidae, Vodokrasidae, Naiadidae, etc. Alismatidae probably originated from some extinct group of herbaceous magnoliids, which stood close to the ancestors of modern nymphaeans.

Subclass 2. Liliids(Liliidae). Herbs or secondary tree forms. Stomata are apomocytic or with subsidiary cells, usually with 2 subsidiary cells (paracytic). Vessels are found only in the roots or in all vegetative organs, and are very rarely absent. Flowers are bisexual or rarely unisexual. The perianth is well developed and consists of similar (usually petal-shaped) or clearly distinct sepals and petals, or the perianth is reduced. Mature pollen is usually 2-celled, less often 3-celled. The shell of pollen grains is single-porous, dioporate (sometimes 1-4-porous) or less often non-aperture. The gynoecium is usually coenocarpous, rarely (in primitive triuriaceae and some primitive liliaceae) more or less apocarpous. The ovules are usually bitegmal or very rarely unitegmal, crassinucellate or, rarely, tenuinucellate. The endosperm is nuclear or less often helobial. The seeds are usually with abundant endosperm, but in the order Zingiberaceae they have perisperm and the remainder of the endosperm or only perisperm.

The subclass of Liliidae includes the orders Liliaceae, Gingeraceae, Orchids, Bromeliads, Rutaceae, Sedgeaceae, Commelinaceae, Eriocaulaceae, Restiaceae, Poaceae, etc. The origin is probably common with Alismatidae.

Subclass 3. Arecides(Arecidae). Herbs or secondary tree forms. Stomata with 2, 4, 6 (most often 4) subsidiary cells. Vessels in all vegetative organs or only in the roots (aronica). The flowers are bisexual or more often unisexual. The perianth is developed and consists of sepals and petals that are very similar to each other, or it is more or less reduced, sometimes absent. The flowers are collected in paniculate or spherical inflorescences or in cobs, which are mostly equipped with a veil. Mature pollen is usually 2-celled. The shell of pollen grains is of different types, mostly single-collate. The gynoecium is apocarpous (some palms) or more often coenocarpous. Ovules are bithemal and crassinucellate, rarely tenuinucellate. The endosperm is usually nuclear. Seeds with endosperm, usually abundant.

The Arecidae subclass includes the orders Palmaceae, Cyclantaceae, Arumaceae, Pandanaceae, and Cataceae. It is most likely that arecids have a common origin with liliids.

Life of plants: in 6 volumes. - M.: Enlightenment. Edited by A. L. Takhtadzhyan, Chief Editor member-corr. USSR Academy of Sciences, prof. A.A. Fedorov. 1974 .

Many years before the onset New Era the ancient Greek student of Aristotle, Theophrastus (372 - 287 BC) sought to classify plants. Of his descriptions, 450 are known cultivated plants, among which he identified trees, shrubs and subshrubs, and herbaceous plants. Theophrastus tried to divide plants according to various characteristics into evergreen and deciduous, flowering and non-flowering, wild and cultivated. He described the differences between garden and wild species of roses, although the concept of “species” at that time, most likely, was still absent.

Until the 17th century, many scientists were interested in the works of Theophrastus; the Swedish botanist Carl Linnaeus (1707 - 1778) even called him the father of botany. Significant works were written by the ancient Roman sages Dioscorides, Galen, and Pliny.

Botany as a science of our era originates around the 15th - 16th centuries, during the Renaissance - the period when printing appeared. Merchants, traders and sailors discovered new lands. Botanists in France, Germany, Denmark, Italy, Belgium, and Switzerland tried to systematize plants. The first illustrated reference books - plant classifiers - began to be called herbalists. Lobelius (1538 - 1616) was the first to complete work with drawings. Everywhere, starting from the 15th century, the first botanical gardens and private collections of strange overseas plants appeared, and travelers became interested in herbariums.

Close to modern botany were the works of the Englishman John Ray (1628 - 1705), who divided plants into dicotyledons and monocotyledons. The German scientist Camerarius (1665 - 1721) experimentally confirmed the guess about the need for pollination of flowers to produce seeds.

But the most detailed taxonomy in botany was determined by Carl Linnaeus, who carefully looked deep into each flower. His first classifier included 24 classes of plants, differing in the number and nature of stamens. The classes, in turn, were divided by him into orders, orders into genera, genera into species. To this day, Linnaeus' classification system has been modified but retained. It was Linnaeus who introduced the Latin designations for the plant from two words: the first denotes the genus, the second word the species. In 1753, He published the work “Species of Plants,” in which about 10,000 plant species were described. By modern concepts The term "species" describes Linnaeus' descriptions of 1,500 plant species.

Linnaeus' theory caused many controversial discussions; until the 19th century, scientists continued to improve the classification, until Charles Darwin's work "The Origin of Species" was published, which gave the clearest idea. However, the 30-volume Soviet publication “Flora of the USSR” is built according to the Engler system; the system of description of plants is ordered to genera, and only in some cases - to species.

In addition to Engler, there are a number of so-called phylogenetic systems proposed by various botanists around the world, based on the teachings of Darwin. Russian-language botanical literature is published according to the system of A. A. Grossheim, in which related species are combined into genera, genera into families, families into orders, orders into classes, classes into types or divisions. Sometimes there are intermediate substructures - subtype, subclass, etc.

By the end of the 16th century, botany had limited information; the main sources of botanical information were the works of Theophrastus, Pliny, Dioscorides, Columella, Albertus Magnus and various herbalists containing descriptions and images of medicinal plants.
The main result of the development of botany in the New Age was the description and classification of a large number of species plant species. Therefore, this period is often called the initial inventory period.

The first attempt to create a natural plant system belongs to the French botanist M. Adanson (1726-1806). While Linnaeus was still alive, in 1763, he published his work “Plant Families,” which implemented the most important idea of ​​natural taxonomy: taking into account the maximum possible number of characters. However, the method that Adanson used turned out to be mechanistic and unsuccessful. He believed that all signs have the same “weight”, the same systematic meaning. Tracing the expression of each characteristic, Adanson built 65 series, or systems, and then compared them, summed them up and obtained an integrated system based on the fact that the more matches, the closer the “affinity”. In total, he described 1,700 genera and 58 families. At one time, Adanson’s ideas did not have a significant impact on the development of science, but in the middle of the 20th century they were revived by supporters of the so-called “numerical” taxonomy, which sought to take into account with the help of computers and use as many features as possible in classification.

Less than in other countries, the influence of the Linnaean system was felt in France, and it is no coincidence that it was here, after Adanson, that the system of A.L. Jussier (1748-1836) appeared, with which, in essence, the era begins natural systems.

Even Bernard Jussier (1699-1777), a contemporary of Linnaeus, botanist and court gardener, in 1759 tried to arrange plants in a natural row, from simple to complex, in the beds of the Trianon Botanical Garden in Versailles. His ideas were developed by his nephew, Antoine Laurent Jussier. In 1789, he published a remarkable work, “Genera of Plants,” which describes about 20,000 species classified into 1,754 genera, 100 orders (families in the modern sense) and 15 classes. Jussier firmly believes that the system should reflect nature, and not be imposed on it. Living organisms are subject to a natural hierarchy and are connected in a single chain from simple to complex (a belief that is undoubtedly close to the idea of ​​Bonnet’s “ladder of creatures”). To reflect this connection when building a system, you need to use a set of features characteristic of each group. At the same time, as Bernard Jussier said in contrast to Adanson, signs need to be weighed, and not just counted.

Based on these principles, Jussier was able to identify fairly natural groups - “orders” and give them successful characteristics. The attempt to represent these natural groups in the form of a coherent, continuous “ascending” chain through a certain arrangement of classes was not crowned with success. In its higher divisions and in the general scheme of construction, the system retained its unartificial nature. Indeed, the number of cotyledons and petals and the position of the ovary are common characters, more diagnostic than the taxonomic ones used in artificial systems. It is clear that when operating with such a small set of characteristics, Jussier’s classes turned out to be for the most part very composite, and the relative arrangement of classes was arbitrary. The reasons for the similarities between taxa are not discussed, they are only stated.

Thus, Jussier’s historical merit is not so much in the development of a specific system, but in the formulation of the idea and its justification. But this was done so convincingly and so solidly supported by excellent, clear diagnoses of genera and orders, illustrating the natural method, that it could not help but attract the attention of contemporaries.

Jussier turned out to have many followers. Under his influence, J.B. Lamarck (1744-1829) revised the first version of his system. In England, a supporter of Jussier's method was D. Lindley (1799-1865), who created a similar system of the “ascending type.” In Austria, S. Endlicher (1804-1849) held similar views; It is significant that even the title of his main work - "Genera of Plants Arranged Following Natural Orders" - (1836-1840) - exactly repeats the title of Jussier's book. In France, Jussier's ideas were developed by the founder of scientific paleobotany, A.T. Brongniard (1804-1876). In Russia, the Jussier system was promoted by Pavel Goryaninov (1796-1805). In his "Principles of Botany" (1841), by the way, the gymnosperms, called "Pseudospermae", are clearly separated from the angiosperms, and the general scheme of the ascending series of taxa repeats that of Jussier.

The German florist I. Bock described about 567 species of plants, uniting closely related plants into groups that are now known as the families Lamiaceae, Asteraceae, Cruciferae, Liliaceae, etc. However, he did not have classification principles; he grouped plants according to their general similarity. However, this classification system was already a big breakthrough in the systematization of plant forms of that time, since Bok’s contemporaries described plants simply in alphabetical order.

In the second half of the 16th century, the Dutch botanist C. Clusius, after studying the European flora and introduced plants from other countries, proposed classifying all plants into the following groups:

1 - trees, bushes and shrubs,
2 - bulbous plants,
3 - good-smelling plants,
4 - non-smelling plants,
5 - poisonous plants,
6 - ferns, grasses, umbelliferae, etc.

Significant success in the development of botany at the end of the 16th century is associated with the Swiss scientist Casper Baugin, who studied and described about 6,000 plant species. Great achievement His works included an accurate description of many forms and definitions of synonyms for the species. In his works one can find the rudiments of binary nomenclature, but his system was not systemic in nature, so there were species that had a four-part name, for example Anemona alpina alba major and Anemona alpina alba minor. However, this does not cast doubt on his method of classification, but testified to his ability to diagnose a species down to its varieties. K. Baugin tried to unite species based on general similarity into certain groups. He divided all plants into 12 groups (books), each group was divided into sections, a section into groups, a group into species. Many sections corresponded to modern ideas of taxonomy. However, systematic units above section rank were mistakenly grouped together, so horsetails, grasses, and ephedra were in the same group.

The works of the French botanist J. Tournefort should be noted. He studied and described about 500 plant genera. He based their classification on the structure of the corolla. Tournefort introduced a new four-fold division of systematic categories into botany: class, section, genus and species. Tournefort's theoretical views were not particularly original, however, they influenced the work of many botanists of the subsequent period.

Intensive work on animal taxonomy began in the 16th century. A typical example of zoological research of that time can be considered the work of the Swiss naturalist Kondrat Gesner. Gesner is the author of the book “The History of Animals” in five volumes, the first volume contained a description of mammals, the second - egg-laying quadrupeds, the third - birds, the fourth - aquatic animals, and the fifth was devoted to grouped animals. The material was arranged in alphabetical order. The description of each species was given in a certain order, first the name of the species was given, then information about the geographical distribution, body structure and life activity was provided, instincts, morals, behavior, significance for humans and information available on this species in the literature were described. Gesner did not have clear nomenclature and terminology when describing the species. In some cases he brought together similar forms, in others he grouped them arbitrarily. The main value of his work lies in the fact that he compiled an extensive zoological summary of animals. In the works compiled by Gesner’s contemporaries, the development of new principles of animal taxonomy is not traced anywhere. Thus, the classification of animals in the works of E. Woton, J. Ray and other researchers was based on the Aristotelian division of animals; it is worth noting that, of course, unlike Aristotle, in these works a larger number of animals was indicated and groups were divided on the basis of not only morphological characteristics, habitat and lifestyle, but also the anatomical achievements of that time.

In the second half of the 19th century. Particularly significant natural systems were developed by German scientists. In 1864, the system of the outstanding morphologist A. Brown (1805-1877) was published. In it, gymnosperms and angiosperms are grouped together under the name Anthophyta, and within Angiospermae the classes monocots and dicotyledons are distinguished. Dicotyledons, in turn, are subdivided into petalless, sphenoletal and free-petalous. In other words, as with Jussier, the same line is built from simple to complex and from small to many. But the most interesting thing in A. Brown’s system is the distinction, in the same spirit, between three levels of organization: Bryophyta (including algae, fungi, lichens, bryophytes), Cormophyta (vascular secretagogues) and Anthophyta. This is sometimes seen as an evolutionary approach, but there is no reason for this. The ideas of development were not alien to A. Brown, but still his constructions remain within the framework of pre-evolutionary natural taxonomy.

Very close to the constructions of A. Brown is the system developed by his successor in the department at the University of Berlin, A. Eichler (1839-1887), the author of the immortal summary of flower morphology - “Blutendiagramme”. Eichler definitely recognized evolution, although he did not set out to reflect phylogeny in the system. He quite correctly assessed clenepetality as a sign indicating specialization. In his system of angiosperms, monocots precede dicotyledons, but among dicotyledons, free-petalous ones, including 21 orders, are placed before spinoletal ones (9 orders).

Parallel to the Jussier-Eichler line with its “ascending” nature of the arrangement of taxa, another line of natural systems developed. It begins with one of the most outstanding botanists of the post-Linnaean era, Augustin Pyramus Decandolle (1778-1841), a keen observer and bright thinker, an excellent morphologist and taxonomist. Decandolle set as his goal to give - for the first time since Linnaeus - a description not of genera, as in Jussier or Endlicher, but of all plant species globe. This problem was solved in 17 volumes of the grandiose work “Prodromus systematis naturalis regni vegetabilis”, i.e. "Harbinger of the natural system of the plant kingdom." Many major taxonomists were involved in working on it. The publication was published for 50 years - from 1823 to 1873, and was completed after the death of the elder Decandolle by his son Alphonse. Although Prodromus is not finished, it describes about 60 thousand species; it still remains and will remain forever one of the most important sources for taxonomists and monographers.

Of course, all this enormous material, even just for the sake of convenience of viewing, should have been arranged according to specific system. Decandolle published the first version of such a system in 1813; subsequently she underwent some changes, but they did not affect her being. In his system, many of the groups identified by Jussier are preserved, but the order of their arrangement is reverse, “descending” - from complex to simple and from many to small.

The strong influence of Decandolle is clearly visible in the system of the English botanists J. Bentham and J. D. Hooker, published in their joint three-volume work “Genera plantarum” (1862-1883). Although this work appeared after the publication of Charles Darwin's book "The Origin of Species" (1859), its authors still stand - at least in their practical activities - from the point of view of the fundamental immutability of species. Their system remains at the pre-evolutionary level, but it is very deeply developed, all descriptions of genera are original, carefully verified; within dicotyledons, an additional taxonomic category was introduced - cohort to unite close families. Cohorts, in turn, are united into ranks. It is clearly unfortunate to place gymnosperms between dicotyledons and monocotyledons, but on the whole this system turned out to be very convenient, and just like the Decandolle system in France and Switzerland, it has far outlived its time and is still used in English-speaking countries.

In general, the situation with the development of systematic principles in zoology was worse than in botany. The divisions within large systematic groups were especially unclear. Of course, this situation occurred due to the distribution of forces, so more time and money were devoted to botanical research of that time, so botany served the needs of medicine, Agriculture and production.

 CHAPTER 3. FROM NATURAL HISTORY TO MODERN BIOLOGY (BIOLOGY OF MODERN TIMES TO THE MID-19TH CENTURY)

3.1. Development of botanical research

The main result of the development of botany during the 15th – 18th centuries. there was a description and classification of a large number of plant species. Therefore, this period is often called the period of “initial inventory” of plants. At this time, the basic concepts of botanical morphology were developed, the beginnings of scientific terminology were laid, principles and methods of classifying plants were developed, and, finally, the first systems of the plant kingdom were created.
3.1.1. Attempts to classify plants in the 16th century
By the end of the 15th – beginning of the 16th century. botany had very limited information, inherited from the ancient world and the Middle Ages. The main sources of botanical information were the works of Theophrastus, Pliny, Dioscorides, Columella, Albertus Magnus, “herbalists”, which contained descriptions and images of a few, mainly useful plants. Almost everything had to start all over again: explore the local flora, understand the vegetation cover, describe its composition, and then, having identified the main forms of plants, try to systematize them and classify them according to certain, easily recognizable characteristics. This work was started by the “fathers of botany” - I. Bock, O. Brunfels, L. Fuchs, P. Mattioli, M. Lobellius, C. Clusius, K. and I. Baugins, etc. In their writings we find descriptions and drawings a significant number of plant species. In the 16th century The compilation of herbaria became widespread.

German florist of the 16th century. I. Bock described 567 species of plants, uniting closely related plants into groups that are now known as the families Lamiaceae, Asteraceae, Cruciferae, Liliaceae, etc. Bock does not have any consciously developed principles of classification. He grouped plant forms according to general similarity. This was already a step forward, considering that some of Bock's contemporaries described plants simply in alphabetical order.

His contemporary L. Fuchs attempted to introduce some morphological terms to facilitate the description and comparison of plants. He also gave descriptions of a large number of plant forms, but they were sometimes very superficial, since he paid attention mainly to the external shape and size of plants. Sometimes Fuchs supplied them with so-called signatures, i.e., characteristics indicating the meaning of a particular plant. But they were very naive. So, if the plant was red, it was said that it helps with blood diseases; if the leaf shape resembled the outline of a heart, it was believed that the plant could serve as a remedy for heart disease, plants with yellow flowers– for the treatment of the liver, etc. Plants belonging to different species were often combined under one name.

In the second half of the 16th century. the Dutch botanist K. Clusius, who extensively studied the European flora and plants brought from “overseas” countries, proposed classifying all plants into the following groups: 1) trees, bushes and subshrubs; 2) bulbous plants; 3) good-smelling plants; 4) odorless plants; 5) poisonous plants; 6) ferns, grasses, umbelliferae, etc.

The Flemish botanist M. Lobellius went somewhat further, whose main works date back to the 16th century. He tried to classify plants mainly by the shape of their leaves. For example, Lobellius identified a group of cereals and, based on the structure of the leaves, brought it closer to the groups of lilies and orchids. At the same time, one can find in him a naive association of all plants growing in the fields, including weeds, into the “genus wheat”.

Significant success in the development of botany in late XVI- early 17th century associated with the name of the Swiss scientist Caspar Baugin. Baugin studied and described about 6,000 plant species, so even in quantitative terms his work marked a major step forward. Baugin's great achievement was very accurate descriptions of many forms, made in the form of brief diagnoses. Baugin identified many synonyms. Not having yet clear ideas about systematic categories, he often used a technique that is now called binary nomenclature. The beginnings of binary nomenclature are also found in Brunfels, Fuchs, and Lobellius. Baugin sometimes gave four-term names, which testified to his ability to very accurately diagnose plants down to varieties (in the modern sense). Yes, he distinguished Anemona alpina alba major And Anemona alpina alba minor. Similar designations used by Baugin, although not always consistently and not for all species, undoubtedly had positive value, as they facilitated the study and “inventory” of the plant world. Let us recall that during this period (up to the work of Linnaeus) species were usually designated by ten or more words. After Baugin, binary nomenclature was also proposed by the German naturalist A. Rivinus.

Baugin, like some of his predecessors, tried to unite species based on general similarity into certain groups. He divided plants into 12 “books”. Each “book” was divided into sections, sections into genera, and genera into species. Many sections, more or less corresponding to the families of modern taxonomy, were outlined quite correctly. Baugin contains the first sketches of a natural system, but they were still very imperfect.

If during this period species received in many cases quite clear characteristics and botanists learned to see them distinctive features, then they distinguished systematic units above genus poorly. It is significant, for example, that horsetails, grasses and ephedra (ephedra) were in the same group in Baugin, as well as duckweed and mosses.

The accumulation of material urgently required the deepening of systematization techniques. The works of the Italian scientist of the 16th century played a certain role in this regard. Andrey Cesalpino, who tried to establish some basic principles classifications.

Following Aristotle, he viewed the plant as an imperfect animal. He considered the main functions of the plant to be nutrition and reproduction. Nutrition, in his opinion, is connected with the root, reproduction - with the stem. Believing that seeds personify the “life principle” of a plant - its “soul”, he proposed that the greatest attention when classifying should be paid to the seeds, fruits and the “shells” that protect them - flowers. Despite the fallacy of his initial positions, Cesalpino rose above purely empirical and often naive methods of classification. However, the classification he proposed (he divided plants into 15 groups) was completely artificial. Cesalpino even mixed monocotyledons and dicotyledons, the difference between which was noted by Baugin.
3.1. 2. Systematics and morphology of plants in the 17th century
The works of the German naturalist and philosopher of the first half of the 17th century were also important for the development of botany and botanical systematics. Joachim Jung. Jung's works laid the foundation for botanical morphology and organography, thereby creating the opportunity for a more in-depth systematization of the material. Jung briefly and accurately diagnosed various plant organs. He insisted on introducing the following principle into science: all plant organs, similar in their “internal essence,” should bear the same name, even if they were different in shape. In other words, Jung came close to the concept of homology of plant organs, thereby providing a clear criterion for comparing different plant organs with each other. He emphasized the need to take into account the entire complex of basic characteristics of plants and rejected the teleological Aristotelian approach to the plant organism characteristic of Cesalpino. Jung's merit is that he clarified the existing and introduced new botanical terminology.

Mention should be made of the “New Taxonomy of Umbrella Plants” (1672) by the English botanist R. Morison and especially the three-volume work “History of Plants” (1686) by the English naturalist John Ray. Ray described many plants, and he relied on Jung's morphological ideas and terminology. Ray divided the plant world into 31 groups. Some of these groups were close to natural (cereals, cruciferous plants, Lamiaceae, moths, etc.). Ray noticed that, according to the structural features of the embryo, all plants are divided into two large groups, now called monocots and dicotyledons. Ray attempted to give a four-fold classification. He distinguished between the concepts of genus and species, and he divided the first of them into three: genus (genus in the narrow sense), genus subalternum (sometimes ordo, which roughly corresponds to order or family), genus summum (class). Ray arranged his “classes” in an ascending series in order of difficulty. Although the arrangement he proposed was still very imperfect, one can see in it the beginnings of that fruitful approach, which was then developed in the works of A. Jussier and especially Lamarck.

Among other works dating back to the second half of the 17th – early 18th centuries, the works of the French botanist J. Tournefort should be noted. Tournefort studied and described about 500 genera of plants. He based their classification on the structure of the corolla. Tournefort distinguished petalless plants, and divided the latter into single-petal and multi-petal. He classified, for example, bells and Lamiaceae as single-petaled, Rosaceae, etc. as multi-petaled. Tournefort divided trees, shrubs and herbs into several classes. In total there were 22 classes in his system.

Tournefort introduced a new four-member division of systematic categories into botany: class, section (a category close to the current order), genus and species. Tournefort gave detailed diagnoses of childbirth. He contains interesting phytogeographical information. Tournefort's theoretical views were not particularly original, however, they influenced the work of many botanists of the subsequent period.
3.1.3. Development of microscopic anatomy of plants in the 17th century
The study of the fine anatomical structure of plants became possible only after the invention of the microscope.

In the XII – XIII centuries. Glasses were invented in craft workshops in the second half of the 16th century. The camera obscura and the first complex optical tube appear.

What is a camera obscura? The term “camera obscura” refers to the classic “dark box with a small hole” that plays the role of a primitive lens.

In the journal “Issues of the history of natural science and technology”, N 4, 2000. very described interesting experiment with a camera obscura, conducted at the State Astronomical Institute named after. P.K. Sternberg (MSU). There is a vertical solar telescope in the SAI building, wide pipe which is 18 m long and runs through the building of the institute from the roof to the basement, which is visible in the picture. Above top part In the pipe there is a coelost of two flat mirrors, which does not distort the purity of the experiment, but significantly facilitates it. A round hole with a diameter of 6 mm was left in the tightly closed upper opening of the pipe, and below, directly above the mirror lens of the solar telescope, at a distance of about 17 m from the entrance hole, we placed a white screen.

The Zenit camera took photographs of the full image of the Sun from the projection screen, as well as direct photographs of individual sunspots with a camera without a lens placed on the projection screen. To compare the quality of the images we saw, the figures show a photograph of the Sun in white light, obtained on June 2, 1998 at the Big Bear Observatory (USA) and the same image, blurred by a numerical method to the state in which it subjectively appeared to us when observed at the same time day on the screen of a camera obscura.

Were there attempts to build giant pinhole cameras before the invention of the telescope?

Are situations of unintentional construction of such devices possible?

Have any observations of sunspots been recorded using random pinhole cameras?

Hypothesis: “The possibility of experimenting with a giant obscura is provided by large architectural structures - medieval Gothic cathedrals or even ancient domed structures like the Roman Pantheon.” Very soon he is given the opportunity to confirm this assumption. In July 1998 he travels to Spain. In Toledo, around noon on July 6, he entered the Gothic Cathedral and began to study the light patterns on the floor. The interior of the cathedral was quite dark, with only a few stained glass windows providing diffused light. Very soon he discovered on the floor several images of the Sun, which owed their appearance, as was clearly visible from the direction of the rays, to the cracks between the individual glasses of stained glass windows located on the southern facade high under the arch of the cathedral. “I note once again that the old stained-glass windows made of thick colored glass very effectively absorb and scatter sunlight, so that despite the “luminous windows”, it is always gloomy in the cathedral. The projections of the Sun that I discovered had diameters from 17 to 30 cm, depending on the height of the stained glass window above the floor. Not all images were High Quality: the brightest ones turned out to be very blurry - apparently, they were generated by large holes that had diameters much larger than the optimal one. But images of low surface brightness turned out to be quite sharp; on them I easily distinguished two large sunspots, however, to my shame, I could not sketch them due to the lack of paper. Having gone out of the cathedral onto the street in search of paper, I was no longer able to get back, since the cathedral was closed for siesta. Fortunately, a day later, on July 8, I had a second opportunity to observe the effect of a camera obscura in the Cathedral of Seville. The photo shows that on the floor of the cathedral there were two images of the Sun of the same size located next to each other - a bright one on the right and a dim one to the left, each with a diameter of 27 cm. The edges of the bright image were very blurred, and it had no internal structure (except for a slight darkening towards the edge). The faint image turned out to be much sharper: sunspots were clearly visible on it. So, there is now no doubt that long before the advent of the telescope, observant natural scientists had the opportunity to notice features of the solar surface and regularly monitor their movement caused by the rotation of the Sun. A giant camera obscura, which appeared accidentally, for example, in a Gothic cathedral, made it possible to systematically observe ordinary large spots.

At the very beginning of the 17th century. microscopes appeared. The invention of the microscope is usually attributed to the Dutch father and son Jansen. There are, however, no sufficient grounds for such a statement. As shown by S.L. Sobol is a major expert on the history of the microscope; this device was first designed by Galileo at the very beginning of the 17th century. Complex two-lens microscopes with convex single objectives and eyepieces, which came into use, appeared in England or Holland in 1617–1619. Their inventor may have been the physicist Drebbel. During the 17th – 18th centuries. The optical system and tripod design will be improved. Objects begin to be viewed not in incident light, but in transmitted light, in late XVIII V. Spherical and chromatic aberrations are eliminated by combining types of glass with different refractive indices.

The progress of microscopic technology was a prerequisite for the success of important branches of biological science, including plant anatomy.

One of the first descriptions of the fine structure of plants was given in the book of the English scientist Robert Hooke “Micrography or some physiological descriptions of the smallest bodies using magnifying glasses” (1665). Hooke described some plant tissues and noted their cellular structure. He could not understand the true nature of these formations and interpreted the cells as pores, voids, “bubbles” between plant fibers.

Italian scientist M. Malpighi in the second half of the 17th century. carefully described the microstructures of leaves, stems and roots. He studied in particular detail the structure of the stem (bark, wood and core).

One day Malpighi was walking in his garden in the evening. Lost in thought, I came across a chestnut branch, broke it off and saw some stripes at the break site. At home, he saw that these were special channels filled with air. And Malpighi began to study these tubes and noticed that some of them contained not air, but plant sap. Through a microscope, Malpighi saw sacs in the roots, bark, stem, and leaves. These bags bothered him for a long time; he found them everywhere, but did not understand their meaning.

Malpighi managed to find out that there are two currents in the stem: ascending and descending. Descending consists of juices, due to which plant tissues live and grow. To test his assumptions, Malpighi made the following experiment. He removed the ring from the trunk small area bark. After many days, the bark above the ring began to swell and a swelling formed due to the accumulation of sap above the ring. This Malpighi experience has become a classic.

He discovered vascular-fibrous bundles and their individual elements and pointed out their continuity in the plant body. He also studied the reproductive organs of plants in detail. But the functions of the flower and its parts remained unclear to him. He likened the ovules to an egg, the ovary to a uterus, etc.

Almost simultaneously with Malpighi, the English naturalist Nehemiah Grew, author of “The Anatomy of Plants” (1682), also studied the structure of plants. He made many subtle and careful observations, established the concept of “tissue,” and described the structure of various plant tissues. Noting that any fabric consists of interweavings of similar elements - fibers, he interpreted fabrics by analogy with lace and fabrics produced by humans, and cells as bubbles between fibers.
3.1.4. K. Linnaeus system
The pinnacle of artificial classification was the system developed by the Swedish naturalist Carl Linnaeus, the author of outstanding works: “Foundations of Botany”, “Philosophy of Botany”, “Genera of Plants”, “Species of Plants”, “System of Nature” and others, which were widely known and had a profound influence on the science of the 18th century.

Since childhood, Karl has been interested in plants. Instead of going to class, he ran into the forest and there he collected and looked at flowers and leaves. As a result of such a frivolous attitude to his studies, Karl’s father, who dreamed of seeing him as a pastor, was advised to send him to a shoemaker for training. But Dr. Rothman persuaded his father to give Karl to him to study medicine. Rothman turned out to be a good educator and teacher, and soon Karl fell in love with Latin, translated the works of Pliny and learned them almost by heart. And he graduated from high school. C. Linnaeus goes to Lund, the closest university town in Sweden. Here he became interested in science. He then transferred to Uppsala University, where there was a good library and botanical garden. There he became interested in plant taxonomy.

The name of Linnaeus is associated with the description of a large number of plant and animal forms, their accurate diagnosis and convenient systematization. Thus, in the second edition of the work “Species of Plants” (1761), 1260 genera and 7560 species were described, with varieties identified separately. Linnaeus divided plants into 24 classes. Unlike Tournefort, who classified plants based on the structure of the corolla and did not pay attention to the stamens, Linnaeus, who recognized the existence of sex in plants, based his classification, called sexual (sexual), on characteristics stamens and pistils. Linnaeus distinguished the first 13 classes by the number of stamens, the 14th and 15th by the different lengths of the stamens, the 16th, 17th and 18th by the nature of stamen fusion, the 19th by the fusion of anthers, the 20th class by the method of fusion of filaments stamens with a pistil style, the 21st class includes monoecious plants, the 22nd class includes dioecious plants, the 23rd class includes plants, one part of the flowers of which is dioecious, the other bisexual, and finally, the 24th class includes secretagogues. Within classes, Linnaeus distinguished orders based on the nature of the structure of the female organs of the plant - the pistils.

Linnaeus' system was artificial. Plants were assigned to one group or another based on individual characteristics. This led to many mistakes, despite all the insight of Linnaeus.

Linnaeus was aware of the artificiality of his system, the conventionality of classification according to arbitrarily chosen characteristics. Striving for a natural system, Linnaeus, in parallel and independently of his 24 artificial classes, introduced another classification. All plants were distributed in it into 65 - 67 orders (it would be better to say families), which seemed natural to him. However, Linnaeus could not give an exact criterion for these orders.

Linnaeus's main achievement is the final approval of binary nomenclature, improvement and “standardization” of botanical terminology. Instead of the previous cumbersome definitions, Linnaeus introduced short and clear diagnoses, which contained a list of plant characteristics in a certain order. He distinguished the following systematic categories subordinate to each other: classes, orders, genera, species, varieties.
3.1.5. Attempts to create “natural” systems in the 18th century
The concept of “natural grouping” has gone through several stages in its development. Some botanists, guided by the general similarity of plants, tried to combine them into natural groups. These attempts did not stop throughout the 18th century. However, methods of artificial classification remained dominant. But even the authors of artificial systems were inclined to believe that nature itself, regardless of the principles adhered to by classifiers, was characterized by a “natural order” and “natural similarity” of plants. Many taxonomists understood that artificial taxonomy was a purely “technical” technique, and were looking for more advanced methods of classification that would reflect the “natural order” in nature, the natural proximity of individual forms.

Speaking about the attempts to build natural systems of the plant world that were made during the period under review, it should be borne in mind that all of them were only close to the natural system.

The level of science of this era, the lack of criteria for systematics (and above all comparative morphological criteria) did not allow these systems to overcome “artificiality”. Moreover, the concepts of “natural” and “affinity” did not include evolutionary content, the idea of ​​\u200b\u200bthe kinship of plant forms. Nevertheless, the desire of Baugin, Rey, Magnol and others to create natural groupings of plants was of great scientific importance. Their work created certain prerequisites for the doctrine of evolution.

Attempts to construct a natural system find even more vivid expression among some botanists of the 18th century. Thus, the French botanist M. Adanson, in his desire to build a natural plant system, sought to use not just one trait, but a complex of them. True, Ananson did not sufficiently take into account the significance of individual characteristics and their qualitative inequality for classification.

Another French botanist, Bernard Jussier, in 1759 grouped about 800 genera of plants in the beds of the royal garden at Trianon in Versailles, uniting them into 65 “natural orders” (more or less corresponding to the natural order that was outlined by Linnaeus). The Trianon plant catalog was published in 1789 in the book “Genera of Plants,” the author of which was Bernard Jussier’s nephew, Antoine Laurent Jussier. System A.-L. Jussier contained 15 classes, 100 orders (roughly corresponding to current families), about 20,000 species. The classes were grouped into three large groups: acotyledons, monocotyledons and dicots. Within monocots and dicotyledons, classes were distinguished according to the presence of an upper, lower, or semi-inferior ovary. Classes and families were arranged in ascending order.

Jussier paid great attention to the question of the criteria to be used when distributing plants into natural groups. He considered it necessary to carefully “weigh” the signs, identifying the most characteristic, important and constant ones, establishing their subordination and noting the correlation between us.

Many groups in Jussier’s system are quite natural in nature and, with one or another modification, have entered into our modern systems. At the same time, remnants of artificial classification are still strong in his system. These include, in particular, the identification of “classes” based on almost a single feature - the position of the ovary. Particularly artificial is the 15th “class”, which contains the dioecious angiosperms “Diclines irrcgulares”. Jussier's closest successors in the construction of a natural system (Decandolle, Oken) abolished this “class”, and its representatives were combined with petalless plants.

A decisive step in a radical reform of the principles of taxonomy was the botanical work of Lamarck. In his work “Flora of France” (1778), he critically reviewed the plant systems of Linnaeus, B. Jussier and Tournefort, clearly established binary nomenclature, identified many synonyms, and for the first time proposed identification tables based on the dichotomous principle. In “Classes of Plants” (1786), Lamarck divided the plant world into 6 classes and 94 families and to a certain extent came close to natural classification. Here he expressed the idea of ​​gradation of different levels of organization.

In “The Natural History of Plants” (1803), Lamarck, who at that time took the position of evolutionism, divided the plant world into 7 classes, containing 114 families and 1597 genera. He arranged all the forms in ascending order from simple to complex. At the base of the plant world he placed mushrooms, algae and mosses, at its top multi-petalled flowering plants. Thus, in an attempt to create a natural system, he went much further than his predecessors, interpreting the relationship between different groups of plants in an evolutionary sense.

Lamarck's works are complemented by works in the field of botanical systematics by one of the creators of modern botany - Auguste Pyramus Decandolle. He participated in the preparation of the third edition of Lamarck's Flora of France (this edition was published in 1805) and was himself the author of one of the original natural systems of the plant world. Decandolle also owns important work on plant morphology. They date back to the beginning of the 19th century.

For the development of botany, the expansion of floristic research in connection with numerous trips to all parts of the world was of great importance. Thanks to this, thousands of new plant species and unique flora of different countries became known. Among these works, noteworthy is the work of I.G. Gmelin “Flora of Siberia” (1747 – 1796), which describes 1178 plant species (of which about 500 new species), S.P. Krasheninnikov “Description of the land of Kamchatka” (1755), containing information about its vegetation, works by P.S. Pallas’s “Travel through the Various Provinces of the Russian Empire” (1773 – 1788) and “Flora of Russia” (1784 – 1788), etc. The great German naturalist A. Humboldt greatly expanded the knowledge of the vegetation cover of the globe. His writings laid the foundations of plant geography.
3.1.6. The Origins of Plant Physiology
The development of botany and, in particular, plant anatomy created the prerequisites for the emergence of plant physiology. Its formation was stimulated by the needs of agriculture, which needed to clarify the conditions that make it possible to successfully grow good harvest. It is no coincidence that the first phytophysiological studies dealt primarily with problems of plant nutrition. The spread in the 17th century played an important role in the emergence of physiology. experimental method and, in particular, the use of methods of chemistry and physics to explain various phenomena in plant life.

The first attempt at a scientific interpretation of the issue of soil nutrition of plants was made by the French artisan B. Pilassi. In the book “The True Recipe by Which All French Can Learn to Increase Their Wealth” (1563), he explained the fertility of soils by the presence of salt substances in them. His statements, which anticipated the main provisions of the so-called mineral theory of soil fertility, were then forgotten and only appreciated almost three centuries later.

The experiment of the Dutch naturalist van Helmont, carried out in 1600 in connection with the study of plant nutrition, is considered to be the first physiological experiment. By growing a willow branch in a container with a certain amount of soil and regular watering, after five years he did not find any loss in the weight of the soil while the branch grew into a sapling. Based on this experience, van Helmont concluded that the plant owes its growth not to soil, but to water. The English physicist R. Boyle made a similar announcement with pumpkin in 1661. He also concluded that the source of plant growth was water.

The imperfection of the initial attempts to apply the experimental method to the study of the process of plant nutrition led its first researchers to the false conclusion that for normal growth and development of plants one clean water. The only positive side of this so-called water theory was that it viewed plant nutrition not as passive absorption of ready-made food by roots from the ground (the opinion of medieval scientists), but as a process occurring due to the active synthetic activity of plants.

The idea of ​​the activity of a plant as a living organism received experimental confirmation and development in the works of M. Malpighi. Based on observations of the development of pumpkin seeds, its cotyledons and leaves, Malpighi suggested that it was in the leaves of plants exposed to sunlight that the “raw juice” delivered by the roots should be processed into “nutritional juice” suitable for absorption by the plant. These were the first statements and timid attempts to scientifically explain the participation of leaves and sunlight in the process of plant nutrition. Malpighi combined the study of the structure of various plant organs with the study of functions. Thus, having described in his classic work “Anatomy of Plants” (Part I, - 1675, Part II - 1679) a number of microscopic structures of the stem, including previously unknown air-filled vessels with spiral thickenings in the walls (he called them tracheae) , Malpighi immediately cited observations concerning the functions of these formations that conduct nutrients. By ringing the stems, he found that water with nutrients dissolved in it moves through the fibrous elements of the wood to the leaves. He explained this movement by the difference in pressure between the surrounding air and the air in the trachea. From the leaves, the processed juice moves along the bark to the stem and to other parts of the plants, providing nutrition and growth. Thus, Malpighi established the existence of ascending and outgoing currents in the plant and their direct connection with the process of plant nutrition. In addition to the vessels conducting nutritious juices, Malpighi noted the existence in wood and bark of various channels containing milky juice, resinous substances and air. In his opinion, a plant needs air just like an animal.

Malpighi's guesses about the participation of leaves in plant nutrition did not attract the attention of his contemporaries, and his data on the movement of plant juices were used only to speculate on the analogy of this phenomenon with the blood circulation of animals. Malpighi’s ideas about plant nutrition were shared only by N. Grew, who believed (1682) that plants absorb food through their roots, here it “ferments” and then goes to the leaves, where it is processed.

More definite assumptions about production by the plant itself nutrients in the course of chemical transformations was expressed in 1679 by the French physicist E. Mariotte. He referred to the fact that on the same soil, different plants produce a wide variety of substances that are not found in the soil; Mariotte also made the first experiments on the quantitative accounting of water released by a plant during the process of transpiration.

Malpighi's ideas, supported by Mariotte's arguments, served to substantiate a new point of view on the problem of plant nutrition, opposite to that which had prevailed for two millennia.

In 1699, the English scientist James Woodward, through carefully staged experiments on growing plants in water taken from various places, showed that plants develop worse in water free of mineral impurities. These experiments convincingly demonstrated the inconsistency of the water theory, but they obviously remained unknown on the continent, and the water theory even at the beginning of the 19th century. enjoyed wide recognition in scientific circles in Europe.

The research of the English botanist and chemist Stephen Gales was of particular importance for the formation of plant physiology. A follower of Newton, he tried to build a doctrine of the movement of juices in a plant and penetrate into the essence of the processes of their nutrition, based on the strict principles of physics. His classic work “Plant Statics” (1727) was devoted to these issues. Gales believed that the absorption of water through the root and its movement throughout the plant occurs as a result of the action of capillary forces of the porous body. He discovered root pressure, and in his observations of plant evaporation, the suction action of leaves in this process. Thus, Gales installed lower and upper end motors, which cause the movement of water in the plant from bottom to top.

He conducted a large number of experiments to study the process of transpiration. Having determined the time that elapses from the moment water is absorbed by the roots until it evaporates through the leaves, Gales calculated the speed of water movement in the plant. He also determined the amount of water evaporated per day by a plant or an individual branch. Measured the intensity of transpiration of plants with and without leaves, at different hours of the day and at different time years, in leaves that are tender and leathery, in illuminated and shaded ones.

Gales determined the approximate force with which the awakening seeds absorb water. He explained the biological significance of swelling, which begins the germination process. It consists in the fact that the mechanical force resulting from it allows the seed shell to break. Swelling also gives them the opportunity to overcome the resistance of the soil particles surrounding the germinating seed.

Gales also did a lot to develop ideas about plant nutrition. He was the first to suggest that most plant matter comes from the air, since gaseous substances are released during decomposition. How air is converted into solid plant matter Gales did not know, but he was a week away from the right decision question, believing that one of the real substances of plants is light, penetrating into the leaves and facilitating this process. Gales even tried to investigate the gas exchange occurring during this process. But since chemists were not yet able to distinguish between the gases that make up the air, a scientific solution to the question of aerial nutrition of plants was impossible. Probably for the same reason, the valuable observation of Charles Bonnet (1754), who established the release of gas bubbles by plants immersed in water in the light and the cessation of this process in the dark, remained incomprehensible.

The name of Gales is also associated with the first attempt at a scientific interpretation of the process of root nutrition of plants. He drew attention to the mysterious phenomenon of soil nutrition of plants - the so-called selective ability of roots when they absorb minerals from the soil.

Gales argued that the essence of the life processes of organisms can only be revealed using the methods of the physical sciences - measurement, weighing and calculations. Borrowing these methods from the laboratory practice of physics, Gales applied them to the study of plant life and obtained brilliant results for that time. The name of Gales became known far beyond England; he is rightly called the “father of plant physiology”, the founder of the experimental method in the study of plant life.

After Geils, the rate of development of plant physiology decreased sharply. Until the 70s of the 18th century. One can note only a few small studies of individual manifestations of plant life, which did not entail any significant changes in this area of ​​​​knowledge, and sometimes meant a step back. In botany mid-18th century V. under the influence of K. Linnaeus, the dominance of a purely systematization direction was established. Scientists returned to the erroneous water theory again and again, and only M.V. Lomonosov raised his voice against this theory. In 1763, in his work “On the Layers of the Earth,” he opposed the water theory as a whole and clearly spoke about the presence of aerial nutrition of plants, carried out with the help of leaves that absorb “fine earthly dust” from the air. Lomonosov expressed the idea of ​​the role of the air as a source of plant nutrition back in 1753 in his treatise “A Tale of Aerial Phenomena Produced by Electrical Force.” However, it went unnoticed by contemporaries and was very soon forgotten.

Almost in the same years, another Russian scientist, one of the founders of domestic agronomy, A.T. Bolotov (1770, 1784), outlined the basic principles of the mineral theory of plant nutrition and criticized the water theory. Clearly realizing the primary importance of soil nutrition for plants, Bolotov developed methods for applying fertilizers to the soil. At the same time, he, however, was inclined to consider ash and manure to be equivalent in effectiveness.

A correct understanding of the role of mineral nutrition of plants also distinguished the works of the famous French chemist A. Lavoisier (1777). He opposed the water theory. Scientific and experimental proof of the correctness of ideas about the great importance of mineral nutrition in plant life and the identification of its patterns was carried out only more than a quarter of a century later by the Geneva naturalist N.T. Saussure (1804).

From the second half of the XVIII V. The humus theory of plant nutrition began to develop. Proponents of this theory believed that soil humus (humus) is of primary importance for plant growth, and soil minerals only indirectly affect the intensity of humus absorption.

Much more successful in the 70s of the 18th century. ideas about aerial nutrition of plants were being formed. This success was largely due to the rapid development in the 50s - 70s of “pneumatic” chemistry, as the chemistry of gases was then called; the improvement of research methods made it possible to discover carbon dioxide (Black, 1754), hydrogen (Cavendish, 1766), oxygen (Scheele, 1773 ; Priestley, 1774), to give a correct explanation of the phenomena of combustion, oxidation and respiration, and also to reveal the inconsistency of ideas about phlogiston.

The first experimenters who studied the importance of air and sunlight in the life of plants - the Englishman D. Priestley, the Dutch doctor J. Ingenhouse and the Genevan botanist J. Senebier - were associated with chemistry in their activities.

Priestley's remarkable works “Experiments and Observations on Various Kinds of Air” (1772, 1780); Ingenhouse's "Experiments with Plants" (1779) and Senebier's "Physical and Chemical Memoirs on the Influence of Sunlight on the Changes in the Bodies of the Three Kingdoms of Nature and especially the Plant Kingdom" (1782) marked not only experimental confirmation of the presence of aerial nutrition in plants, but also the beginning his comprehensive study. Priestley's experiments, which he began in 1771, indicated a certain relationship between the plant and the air environment under sunlight. However, by themselves, without explaining the reasons for this phenomenon, they could not lead to the development of a new doctrine. They only gave impetus to continue work in this direction. Dependence of plant absorption of carbon dioxide and oxygen release on solar lighting for Priestley it became clear only in 1781 after Ingenhouse in 1779 revealed the main condition for photosynthesis - the presence of light and the green color of plants. And in 1782, Senebier’s discovery followed - the participation of air carbon dioxide in this process, which brought to the forefront the question of aerial carbon nutrition of plants. Thus, the studies of Priestley, Ingenhouse and Senebier complemented each other, since they concerned different aspects of photosynthesis, without studying the totality of which it was impossible to reveal its essence. The concept of photosynthesis as a process of aerial nutrition of plants under the influence of sunlight, put forward shortly after the publication of the works of Priestley, Ingenhouse and Senebier, became a topic of discussion in scientific circles. Most English scientists unconditionally accepted this position and were even inclined to consider air almost the only source of plant nutrition. On the contrary, Lavoisier, who became interested in this issue in the last years of his life, proposed considering aerial nutrition of plants in combination with mineral nutrition. Nevertheless, some scientists opposed the idea of ​​aerial nutrition of plants in general and, in particular, against Senebier’s experiments on the absorption of air carbon dioxide by plant leaves.
3.1.7. Development of the doctrine of sex and physiology of plant reproduction
Some scattered information about the presence of sex in some plants was available in ancient times; this knowledge was then used in artificial pollination date palms. However, until the second half of the 17th century. the question of sex in plants seemed unclear.

At the end of the 16th century. The work of the Czech botanist Adam Zaluziansky “The Herbarium Method” was published. Zaluzyansky expressed the idea that among plants there are “androgynous” (i.e., hermaphroditic) and dioecious (dioecious) species. He warned against possible confusion of sexual differences and species characteristics.

In the 17th century Grew described stamens, pollen grains, pistils, ovules, plant seeds and expressed the opinion that stamens and pistils are related to the generation of seeds. J. Ray expressed similar thoughts, although to Ray, like Grew, much in this area remained unclear. At the same time, Malpighi interprets the stamens (and petals) as organs that serve to secrete “excess liquid” from plants and “clean” the juice used to build seeds.

The first attempts to experimentally prove the presence of sex in plants date back to 1678, when the curator of the Oxford Botanical Garden, J. Bobart, showed on the dioecious carnation plant Lychnis the need for pollen produced by male flowers for the formation of seeds in female flowers.

Clear and complete experimental evidence of the presence of sex in plants was given by the German scientist R. Camerarius. He carried out a series of experiments on dioecious and monoecious plants (blue, corn, spinach, hemp, etc.) and came to the conclusion that there is sexual differentiation in plants. “Just as the anthers of plants are the place of formation of the male seed, so the ovary with its stigma and style corresponds to the female genital organs...” wrote Camerarius. “If,” it was said further, “there are no anthers of a male flower or a style of a female one..., then the embryo will not form.” Camerarius spoke about the prevalence of hermaphroditism in the plant world, admitted the possibility of fertilization of plants of one species with pollen of another species, etc. The reproduction of secretagogous plants was studied in the 18th century. Micheli, Schmiedel, Hedwig and others. Micheli discovered spores in cap mushrooms and understood their importance for reproduction. But the main thing in this area was clarified only in the 19th century.

The works of Linnaeus were of undoubted importance for the development of the plant. In addition to the fact that the idea of ​​sex in plants is reflected in the system of the plant world proposed by Linnaeus, he himself made many observations on plant pollination and conducted experiments with 11 species to understand the processes of fertilization. In 1760, for his essay “Inquiry into the Various Fields of Plants,” he was awarded a prize from the St. Petersburg Academy of Sciences.

Closely related to the study of plant sex and reproduction are studies of hybridization, which have provided extensive material not only for understanding the processes of pollination and fertilization, but also for judging the variability of species. Particularly significant successes in this area are associated with the name of I. Kelreuter, who worked in Germany and Russia. Although the essence of sexual reproduction and its “mechanisms” remained largely unclear to Kohlreuter, he did not doubt the truth of the idea of ​​“generation through two kinds of seeds” and the existence of sex in plants. He became convinced of this primarily through experiments on artificial hybridization. He worked with 50 species of plants, belonging in particular to the genera Nicotiana, Dianthus, Verbascum, and obtained many hybrids - “plant mules”. The hybrids turned out to be intermediate in form between both parental species. Reciprocal crosses gave similar results. All this strengthened Koelreuter in the idea of ​​the need for both male and female “seed” to form a new generation. As for the very essence of fertilization processes in plants, it was revealed only in the first third of the 19th century. In the 18th century the popular view was that a certain “fertilizing evaporation” emanates from the seed (or pollen); Linnaeus believed that the male and female “seminal fluids” mixed on the stigma.

Koelreuter's works contained descriptions of some phenomena important for understanding heredity. Thus, he noted the special power of the first generation of hybrids and resorted to the type of crossing that is now called analyzing; noticed the phenomenon of splitting in the offspring of hybrids, etc. Koelreuter (and before him F. Miller and Dobs) described the role of insects as pollinators, but he considered self-pollination to be the main form of pollination and did not understand the role of cross-pollination.

The research of the German botanist K.H. is of great importance. Sprengel. His works went unnoticed by his contemporaries, and only Darwin appreciated them. Sprengel's work " Mystery Revealed nature in the structure and fertilization of flowers" (1793) was one of the most serious biological works of that time; its main provisions have retained their significance to this day. By observing 461 plant species in nature, Sprengel proved that various features The structures and colors of flowers are adaptations that ensure pollination of plants by insects that carry pollen. One of Sprengel's biggest discoveries was the discovery of dichogamy. He showed that in a number of plants the pistils and stamens do not mature at the same time and this prevents their self-pollination (a phenomenon noticed, but not understood by Koelreuter). Thus, Sprengel discovered one of the most remarkable devices in flora. However, despite the presence of these works, in the ideas about the field of plants in the 18th century. and even in the first third of the 19th century. there was no unanimity.

It should be emphasized that the works of Russian scientists - A.T. - played a significant role in the protection and development of correct ideas about sex in plants. Bolotova, V.F. Zueva, I.M. Komova, N.M. Maksimovich-Ambodik, V.A. Levshin and others. The works of A.T. were especially important. Bolotov, who not only correctly assessed and described the essence of sexual differences in plants and the role of cross-pollination, but also noticed dichogamy (in the apple tree) and even came to understand the biological significance of cross-pollination for increasing the biological power of the offspring. Somewhat later (in 1799), the same thing was noted by the English scientist T. Knight, who wrote about the “stimulating effect of crossing.”

Remember from the textbooks “Plants. Bacteria. Fungi and lichens" and "Animals" with the names of which scientists is the origin of zoology and plant taxonomy associated. What contributions did these scientists make to biology?

In nature, all organisms form separate, independently existing species of plants, animals, fungi, etc. Currently, over 2 million of them are known. The diversity of species of organisms poses questions to science: how did species arise, what is the reason for their diversity? The answers to them are given by the doctrine of evolution (from the Latin evolution - deployment) - a section of biology that examines processes historical development organic world on Earth.

The first attempts to classify organisms. The first who tried to classify organisms was the ancient Greek scientist Aristotle (Fig. 114). He divided everything animal world on animals with blood (vertebrates) and animals without blood (invertebrates). He was also the first to use the term “species” to designate organisms, which he used to designate animals that are similar in external and internal structures. The first species of animals, Aristotle believed, arose through spontaneous generation from sunlight, mud and soil, and new species are formed as a result of crossing existing ones.

Rice. 114. Aristotle (384-322 BC)

The first attempt to classify plants was made by Aristotle’s student and follower, the ancient Greek scientist Theophrastus (Fig. 115). He identified several groups of plants, for example: trees, shrubs, subshrubs and herbs; land and water; deciduous and evergreen. Theophrastus pointed out the variability of plants under the influence of climate and the possibility of the degeneration of some plant species into others.

Rice. 115. Theophrastus (370-285 BC)

The origin and development of taxonomy. Creationism. For a long time, the term “species,” introduced by Aristotle, had no scientific content and was used only as a conditional concept. With the development of systematics - the science of classifying organisms, the species gradually becomes its basic unit. The English naturalist John Ray (Fig. 116) was the first to develop the doctrine of species and tried to determine the characteristics by which one type of organism differed from another.

Rice. 116. John Ray (1627-1705)

Rey considered the main characteristic of a species to be the ability of organisms belonging to the same species to reproduce their own kind. Thus, he called a plant species a group of organisms that produced exactly the same plants from their seeds. However, Ray failed to systematize the species. This work was carried out by the Swedish scientist Carl Linnaeus (Fig. 117), who is considered the founder of taxonomy.

Rice. 117. Charles by Line (1707-1778)

In his book System of Nature in 1753, Linnaeus described more than 10,000 species of plants and animals and developed principles for their classification, thereby ending the confusion of names that had reigned in science since the times of Aristotle and Theophrastus. The type of organism Linnaeus began to consider as the main systematic unit, represented in nature by quite realistically existing individuals having a similar structure. Linnaeus united related species of organisms into larger systematic groups - genera, similar genera - into orders and orders, and orders and orders - into classes.

Thus, Linnaeus' taxonomy was based on the principle of hierarchy (subordination) of systematic units of various ranks - from species to class. With the further development of systematics in science, other systematic categories appeared, such as family, phylum and kingdom.

Linnaeus widely disseminated double nomenclature in science, according to which each type of organism has only one inherent name, consisting of two words - generic (noun) and species (adjective). The name is given in Latin. For example, the full name of the plant Violet dog is written as Viola canina (Viola canina). Scientists still use double nomenclature today.

The system of the organic world into which Linnaeus united all species of plants and animals known at that time was artificial. The characteristics he chose to classify organisms were arbitrary and did not take into account their origin and kinship. Thus, Linnaeus took the structural features of a flower as the basis for classifying plants - the number of stamens and pistils (Fig. 118). Therefore, unrelated species fell into one class, and closely related ones into different ones. Linnaean classification of animals was just as artificial. He based it on the structural features of the circulatory system, without taking into account other features.

Rice. 118. Classification of plants according to Linnaeus: A-X - different classes of plants

While recognizing the reality of the existence of species in nature, Linnaeus at the same time denied the possibility of their changes and development. “There are as many species,” wrote Linnaeus, “as the Infinite Being, that is, God, created them.” Such views on the immutability of species are called creationism (from the Latin creatio - creation). Creationism recognized the divine creation of nature, its original purpose and immutability.

Transformism. The gradual accumulation of information about the variability of species of organisms led to the emergence in science of the ideas of transformism (from the Latin transformare - to transform, transform) - the idea of ​​​​the variability of organisms under the influence of natural causes and the transformation of some species of plants and animals into other species. The idea of ​​transformism was first formulated by the French scientist Georges Louis Buffon (Fig. 119). In his work “Natural History” he expressed the idea of ​​the variability of animals and plants under the influence of conditions external environment: climate, food and human domestication. However, Buffon’s transformism only formally opposed creationism; this scientist did not provide any evidence of the changeability of the organic world.

Rice. 119. Georges Louis Buffon (1707-1788)

Lamarckism. The first evolutionary theory of the development of living nature, supported by facts, was created by the French naturalist Jean Baptiste Lamarck (Fig. 120). In his work “Philosophy of Zoology” in 1809, he revealed the reasons for the evolution of the organic world and formulated three evolutionary laws according to which the development of living nature occurs.

Rice. 120. Jave Baptiste Lamarck (1744-1829)

According to Lamarck's theory, later called Lamarckism, all types of organisms are constantly changing in the direction from simple shapes to complex. Speaking about these changes, Lamarck denied the reality of the existence of species in nature and believed that this category was invented by scientists only to facilitate the classification of organisms.

The main reason for evolution according to Lamarck is the desire of organisms for self-improvement, which is innately inherent in each of them. This desire encounters obstacles in the process of evolution - the need to adapt organisms to environmental conditions. In organisms that do not have nervous system, for example, plants, it is achieved through direct adaptation to environmental conditions - this is the law of direct adaptation. Thus, the arrowhead plant, growing along the banks of reservoirs, forms three forms of leaves, depending on environmental conditions: arrow-shaped aerial, floating round and ribbon-shaped underwater (Fig. 121).

Rice. 121. Modification of leaves of arrowhead: 1 - underwater; 2 - floating; 3 - air

In organisms with a highly organized nervous system, adaptive changes are carried out through exercise or non-exercise of organs - this is the law of exercise and non-exercise of organs. For example, the long neck of the giraffe, according to Lamarck's theory, developed as a result of constant exercise in eating the leaves of tall trees (Fig. 122). The absence of legs in snakes is the result of crawling on the ground and not exercising the limbs that their ancestors had.

Rice. 122. Giraffes

The characteristics of organisms acquired as a result of direct adaptation, exercise or non-exercise of organs, are always transmitted to their offspring. This is stated by Lamarck's third evolutionary law - the law of inheritance of acquired characteristics.

Lamarck's ideas about driving forces evolution (the three evolutionary laws) were wrong. At the same time, Lamarck's work also had progressive significance for the development of science. He created the first evolutionary theory, supported by facts, and noted its progressive nature. Lamarck also developed the basic principles of classifying animals and plants in the form of a family tree from protozoa to humans and introduced the term “biology” into science.

Exercises based on the material covered

1. Who first introduced the term “species” into science?
2. What significance did Linnaeus's works have for science?
3. What were Linnaeus' views on the origin of the organic world?
4. What significance did Buffon's works have for science?
5. What is the essence of the first evolutionary theory, put forward by Lamarck?
6. Compare the views on species and evolution of Linnaeus and Lamarck.

Carl Linnaeus considered each type of organism as a descendant of the original parental pair created by God, preserving all its characteristics unchanged. Towards the end of his life, Linnaeus, under pressure from scientific facts, was forced to admit the variability of species in nature. He explained them by the influence of climate, food and other conditions, also allowing for the possibility of hybridization in nature of existing species.