[Animals (Animalia) in the system of organisms. 1. Typological systems].

Since times of Aristotle animals were considered as a group, opposing to plants. The last were distinguished by two characters. Plants as distinct from animals live the attached way of a life and all nutrients receive from a substratum on which live and from the surrounding air. Animals live an active way of life and exist due to digestion. Fungi at such definition belong to plants. Only in second half of XX centuries due to works of Whittaker and of Tachtadjan fungi have received the separate status equally with plants and animals. In this new system of a plant embraced either oxygenic phototrophs, or photosynthetic eukaryotes. The traditional characters distinguishing animals from plants and fungi are in detail analysed. Many of them appeared formal, not reflecting the structure of relationship. Comparing heterotrophs some authors saw in absorptive nutrition the main difference of fungi from animals. However on mechanisms of receipt of substances in a cell fungi, animals and plants do not differ. Phagocytosis and pinocytosis (clathrin-mediated endocytosis), considered as the most characteristic feature of animals, are revealed both in fungi, and in plants. On photosynthetic activity plants form heterogeneous group, differing on primary and secondary plastids. The last besides have the various origin connected to symbiogenesis of the host cell with red or green algae. Heterotrophy cannot be considered as a uniting attribute of fungi and animals. It is essentially different and focused on diverse food sources. Evolution of animals is connected to perfection of structure of a plasmatic membrane and saturation by its molecules allowing a cell, and through it all organism to be guided in an environment and adequally to be up to external irritants. At a cellular level animals use the various mechanisms of cellular activity connected to moving of cells, their combination in aggregates and complexes or, on the contrary, separation in new cellular configurations. The complex of cellular adaptations connected to the analysis of external signals and adequate response to them of cells, underlies the phenomenon of irritability. At a cellular level irritability is mediated through work of the actin apparatus. Lamarck in "Philosophie zoologique" considered irritability as the main distinctive feature of animals. Evolution of plants and fungi went in a direction of development of a secondary metabolism. The secondary metabolism, concerning synthesis of protective substances, is peculiar to all sedentary organisms, including the animals.

[Animals (Animalia) in system of organisms. 2. Phylogenetic understanding of animals].

The development of systematics in last decade has shown that typological classifications of five-six Kingdoms is not adequate for describing the diversity of organisms. Information from the sequences of small subunit rRNA is not sufficient to reconstruct the position of eukaryotes on the phylogenetic tree due to the effect of long branches. Totally new reconstruction of eukaryotic phylogeny was built upon the analysis of many new molecular markers. Evolution of eukaryotes had two mainstreams. One has been connected with diversification of ancestral biciliate forms (Bikonta). Sister-group of Bikonta (Unikonta) includes some originally uniciliate amoebae and moulds (Amoebozoa), and uniciliate eukaryotes with posterior cilium (Opisthokonta). The taxon Opisthokonta unites Fungi, Nuclearimorpha, Mesomycetozoa, Choanozoa and Metazoa. The latter three groups or only Metazoa are attributes to animals. The following differentiation of the groups used in systematic for the description of diversity of organisms is proposed. (1) Taxon is a group which is defined on the basis of ancestry: taxon includes all species descended from one ancestor. Taxon differs from logic classes of typology at an ontologic level. Taxon arises and exists, and its composition and occupied niches can constantly change; taxon can flourish or, on the contrary, fade up to full disappearance. Thus, the predicative characteristic of taxon, including characters which are considered significant, are not absolute. It is significant only at the moment of consideration. But characters (synapomorphies) are important as the practical tool for discerning taxa at given time period. Taxa unite species into unique classification. This understanding of taxon corresponds to monophyletic group sensu Willi Hennig. (2) Class of organisms is a group which is defined on the basis of characters: class includes all species having the given character. The class is only a logic object. Unlike taxa grouping species into classes may be through different and crossed classifications. Inside the given category of groups it is possible to distinguish: (2.1) Level of the organization (grade) described by the differences on the levels of organization: for example prokaryotic and eukaryotic levels of the organization. Eukaryotes can be divided into unicellular (Protoctista, Protista) and multicelluar (tissue-specific-Histonia) forms. (2.2) Types of the organization distinguishing groups of one level: for example, amoedoid type (Sarcodina), naked (Gymnamoebia), and testate (Testacea) amoebas. (2.3) Taxonomic groups as set-theoretical approximations of taxa. (2.4) Groups of the mixed nature. For example, Haeckel has recognized Protophyta and Protozoa describing the unicellular level of the organization inside plants and animals accordingly. Protozoa in Cavalier-Smith's system (2002, 2004) is also an example of groups of the mixed nature.

[Highest level of division in classification of organisms. 3. Monodermata and Didermata]. / Vysshii uroven' deleniia v klassifikatsii organizmov. 3. Odnoplenochnye (Monodermata) i dvuplenochnye (Didermata) organizmy.

The deepening our knowledge and embrassing the larger array of the investigated organisms leads to replacement of typological classifications with phylogenetic ones. This process seems to be the main stream of modern systematics. But typological classifications have not lost the value, remaining the important tool of the description of phylogeny. It is especially obvious today when molecular reconstructions are using so widely. However resulted phylogenetic classifications are difficult for understandable interpretation. Therefore phylogeneticist is interested in elaboration of typological classifications that can help to explain the results. As an example the phylogenetic classifications of organisms proposed recently by Cavalier-Smith (1998, 2002) and Gupta (1998, 2000) are considered. The modified system of Gupta is the most adequate description of organism phylogeny. Basal clostridia and togobacteria have to the greatest degree kept features of a common ancestor of organisms. From this common ancestor evolution spread by two phyletic lines. One of them included Gram-negative bacteria. The main groups of them have branched of from a common ancestor in the following order: (Deinococci, Chloroflexi) --> (Cyanobacteria) --> (Chlamydia, CFB, Fibrobacteria, Chlorobia) --> (Aquificae) --> --> (Epsilonproteobacteria, Deltaproteobacteria) --> (Alfaproteobacteria) --> (Betaproteobacteria) --> --> (Gammaproteobacteria). In other phyletic line the main groups were separated in the following order: (Thermotogae) --> (Clostridia, Fusobacteria) --> (Bacillae) --> (Actinobacteria). Exact position of archaebacteria and eukaryotes related to this line remains unclear. Typological division of organisms into Didermata and Monodermata (Gupta, 1998) corresponds to these two branches of a cladogram. The cell of the diderm organisms is covered with two membranes, plasmatic and outer. The cell of the monoderm organisms has only one plasmatic membrane. Development of the cellular organization at the earliest stages of evolution of a life went through use of non-lamellar (non-bilayer) lipids which could give a cell with one membrane (not two membranes as in the scenario of Cavalier-Smith (2001)). Membranes appeared at the earliest stages of the evolution of life. Therefore their distinction is quite logical to take as a principle the first typological division of organisms. At the same time the typological classifications considered beyond the framework of phylogenetics, have no independent value. Typological classifications do not give monothetic division into groups. Always there are exceptions. So, among Monodermata there are Gram-negative forms (Acidaminococcaceae, Syntrophomonadaceae, some Thermoanaerobacteriaceae), which are didermic.

[Highest level of division in classification of organisms. 2. Archaebacteria, eubacteria and eukaryotes]. / Vysshii uroven' deleniia v klassifikatsii organizmov. 2. Arkhebakterii, éubakterii i éukarioty.

In three-domain system of organic world archaebacteria are considered as the third form of life alongside with eubacteria and eukaryotes. The author gives brief characteristics of all three groups with special focus on such diagnostic attributes as: plasmatic membrane and cellular wall, flagella, protein transcription, replication, topoisomerases, transcription, translation, glycosylation, chaperons and chaperonins, proteasomes and exosomes, histones, ATP-ases. The three-domain system has been proposed by several scientists but principal ideas were put by C. Woese. The systematics according Woese should reflect contemporary level of our knowledge of organisms. In the historical plan it once had to refuse dividing the organic world into plants and animals but accept the division into prokaryotes and eukaryotes. The science however goes further and turns now to the new level of generalizations based on the molecular aspects of cellular structures and processes. From this point of view, both plants and animals are uniform. As to prokaryotes they appeared to be non-monolithic group because of essentially different transcriptional and translational mechanisms. Therefore the detachment of archaebacteria as an independent group was the important step in the development of systematics. At the same time the three-domain system of organisms is typological and requires correction according to data on phylogenetic relatedness of these groups.

[Highest level of division in the organism classification. 1. Prokaryotes and eukaryotes]. / Vysshii uroven' deleniia v klassifikatsii organizmov.1. Prokarioty i éukarioty.

The works on the general classification of all organisms are considered as a convenient opportunity to sum up numerous data obtained in organic world studying. The present stage is characterized by rapid development of the molecular reconstructions that have already caused considerable changes in our classification practice. These changes look especially impressive at studying the organism cellular structure. The great massive of new data allow us to compare Prokaryotes and Eukaryotes on the nucleic acids and especially proteins whose number in Eukaryote cell approaches to several thousands. Basing on the structure of macromolecules one can hypothesize with great certainty about Prokaryote or Eukaryotes origin. The article presents the detailed characteristic of Prokaryotes or Eukaryotes with the emphasis placed on the comparative analysis of biological macromolecules. Among specially considered cellular structures and processes are cell wall, intracellular components, cellular cycle, nucleus, DNA compactness, replication, genome organization, transcription, posttranscriptional modifications, introns, ribosomes and translation, cytoskeleton, mitosis, cytokinesis, cellular organelles, intracellular membranes systems, modes of nutrition, sexual condition. The macromolecular analysis let to carry out the homology of structures and to find out some new connections. It was shown that typology considered as a search for morphological patterns within the biodiversity structure has almost exhausted the subject. It was directed mostly to distinguishing "main" group in contrast with intermediate and aberrant ones, which were considered as minor phenomenon. At present due to macromolecules systematics it is able to estimate the whole diversity of forms including typologically transitive.

[The problem of archetype and current biology]. / Problema arkhetipa i sovremennaia biologia.

Two ideas of homology--transformational and taxic--are used in biology. The first one deals with homology of different structures from morphological point of view, the second one--with the homology of characters. The main question of taxic homology is: in what cases the same character is not identical in two different species? Transformational homologies are determined according the archaetype, taxic ones--according inheritance from the common ancestor of comparing taxa. Archaetype is an idea of an organism from the position of its components. Archaetype should be distinguished from the type character, i.e. the description of an organism combining general and special features. The main idea of archaetype is an idea of coherence of characters describing morphological organization. Archaetype was considered by Owen as mechanical construction. As a matter of fact, the organism is a dynamic system Its dynamic nature can be demonstrated by the conception of module organization of living systems. In the framework of this conception archaetype is a description of an organism from constructive position, focused on the characters of the parts reflecting ontogenetic and evolutionary autonomy. The progress in developmental genetics in understanding of genetic mechanisms of spatial structure formation during the last years opens the wide perspectives in interpretation of archaetype idea. Homeobox family of genes of Hox complex is especially interesting from this point of view. They are characterized by colinearity: spatial and temporal sequence of their expression is corresponding to their order in chromosome. As it was shown by several experiments, changes in the level and sequence of expression of Hox genes result in the changes of archaetype. The discovery of homological genes determining non homological morphological structures in non related groups is a new challenge to morphologists studying the problem of homologies. The disagreements on this subject are connected with non critical use of transformational (archaetypical) and taxic approximations. From transformational positions, eyes of vertebrates and invertebrates are homological, although they have different structure. At the same time, if we specify what type of eyes we are considered, the results will change. Thus, compound eyes of insects and bivalve mollusk Arca are not homological because they originated independently from forms without compound eyes.