by Vadim NAZAROV, Dr. Sc. (Biol.), Chief Researcher, Institute of History of Natural Sciences and Technology, Russian Academy of Sciences

Paradoxical as it may seem, the theory of biological evolution is still being taught to students at the level of knowledge of 70 years ago. However, despite this situation, the science of evolution has been making good headway, and starting from the 1960s, it has been enriched by many outstanding discoveries. They have formed a base for a new systemic model of evolution, alternative to modern Darwinism. An important part of these achievements is due to Russian scientists.

Our notions on heredity, variability, natural selection, the evolutionary course and direction, on mechanisms and interpretation of species formation have changed radically during the latest 35 years. The description methodology has changed as well. The merely reductionist interpretation based on the statistically probabilistic processes and expressed in the synthetic theory (STE) was replaced by a systemic concept, which fully acknowledges the significance of the individual for the future of its genus in accordance with universal biological laws. The populationist approach has thus lost its role, and the typological approach has again won recognition, as it was in the 19th century. Evolutionists have again turned to a living organism and data of all sciences investigating its integrity: morphology, anatomy, embryology, and biology of individual development.

Biologists are used to attribute the function of inheritance solely to the specific molecules of nucleic acids (DNA and RNA). But this is a one-way and therefore, erroneous viewpoint. Summing up the data of molecular genetics and developmental biology, Leonid Korochkin, Corresponding Member of the Russian Academy of Sciences, inferred in 2002 that a complex comprising the cytoplasm, the architecture of the ovicell, and maternal genome evolves as a connecting link between generations of bisexual organisms. Paradoxical as it may seem, genetic changes are not so much the basis of evolution, as was considered just recently, but rather are its product.

Russian scientists Yuri Altukhov, the geneticist, RAS member, and Yuri Rychkov, the anthropologist, have made a decisive contribution to the alternative theory of

Articles in this rubric reflect the authors' opinion. - Ed.

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species formation, thus undermining the very basis of STE. In 1972 they discovered the structural and functional duality of the genome in higher (eucaryotic) organisms. They found that this genome contains two groups of gene loci: one coding for proteins responsible for the entire vast intraspecies polymorphism and the other coding for monomorphic and invariant proteins, responsible for the absence of corresponding variability of hereditary characters in all subspecies and their entire area. The othergroup of proteins determines the key vital functions inherent in this very species as a unique formation. In other words, such proteins express the species characters highly conserved due to their vital significance in particular.

Before Altukhov and Rychkov none had ever studied the monomorphic part of the genome since it exhibits no variability, and is therefore unavailable for studies, though this part occupies 1/2 to 2/3 of the genome. Only significant reorganization of this part of the genome occurring but rarely (in systemic mutations, gene duplication, and polyploidy) can engender new species. As for the polymorphic part, it provides for an adaptive "strategy" of a species, not directly related to its evolution.

This discovery had one important result. Sergei Meien, a Moscow paleobotanist, found that a new species is born with the same set of subspecies and races which existed in its ancestor-they are inherited. He called this regularity transitive polymorphism (1978). This regularity is valid not only for the species level of organization, but is universal: a taxon of any level, up to the order, inherits the internal structure of its ancestor with all inherent characters. That is the taxonomic variety reproduces itself. Such a course of evolution explains why parallelisms, but not the Darwinian divergence, are predominant in living nature.

Close studies of parallelisms helped Meien discover their repetitive structure and make the main conclusion: the basic trends of similar evolutional transformation of characters in different taxa constitute an immutable law of morphology (typology). This law reflects the systemic nature of objects and is manifested irrespective of environmental conditions. This conclusion extended the framework of the law of homologous series formulated by Acad. Nikolai Vavilov in 1920 relative to hereditary variability and formed a universal causative base for it*.

The formation of a new model of evolution was largely determined by ground-breaking achievements in molecular genetics: by the notions of the systemic organization of the genome; by the discovery of non-mutational forms of variability; of mobile genetic elements and horizontal transfer of genetic information; of systemic and "directed" mutations; of chromosomal species formation; of the role of stress in evolution, and so on. Since it is hardly possible to describe all discoveries in a short paper, we have to confine ourselves to selected data.

American geneticists Jack King, Thomas Jukes (1969), and Nobel Prize winner Motoo Kimura (1968) have shown that there is no direct correlation between geno-typical (molecular) and morphological evolutions, for they are separated by events at the epigenetic level. This very fact voids all attempts at describing evolution through the genes, their point mutations and frequencies, as suggested in the mechanistic model of STE. As for the epigenetic sphere, two new, non-canonical forms of variability were discovered. It all began with the discovery made by Mikhail Golubovsky, a Russian geneticist, in 1978, who established a two-component structure of the eucaryote genome: obligate (ОС) and facultative (FC) ones. The fractions of the former are rather stable, while those of the latter are liable to change. Both persist in close interactions: informational molecules migrate freely between them. According to M. Golubovsky, this interaction is the main source of hereditary changes in nature. The information flow "environmental factors → FC" leads to changes in the genome structural components, which he called variations. The second form of variability is known as dynamic, or epigenetic. It is related to changes in gene activity, or genotype main memory.

The discovery of these new forms of variability, more potent than mutations and predominating in nature, has clarified the mechanism of such phenomena as persistent modifications and mass changes of directed type underlying the virtually instantaneous formation of species.

In the light of new data on the genome structure and function, the discovery of genome instability and of the existence of a special class of mobile (transposable) genetic elements (MGE), or transposons, made by the USA geneticist Barbara McClintock, Nobel Prizewinner (1983), was finally acknowledged. These elements migrate in the genome, insert into definite loci, and cause mutations of respective genes, with the incidence of such mutations surpassing the common rate by thousands of times. When this happens, mass populational changes of certain nature are observed. Acad. Lev Berg described such changes as far back as in 1922. This mutagenesis (insertion) in natural populations has already been studied in detail by many authors. According to Dr. Golubovsky, by now more than 30 MGE families are known in Drosophilidae fruit flies, their percentage in the Dr. melanogaster genome being as high as 15 percent.

Organisms of different groups have been found to be involved in the mutual exchange of transposable elements, irrespective of their systematic closeness, and a genofond (gene pool) common to all living organisms exists in the biosphere, from which any species can get the needed genetic information. Hence the concept of horizontal transfer of genetic information and the notion of the informational factor of evolution explaining the facts of sudden species formation actually led to the revision of our previous knowledge. Biological species now figure as potentially open genetic systems. Molecular genetics has

* See: V. Dragavtsev, "Serving the Common Good", Science in Russia, No. 3, 2003. - Ed.

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Examples of monstrous, though viable, forms (fossils): a - Stegosaurus; b - Pteranodon.

thus changed beyond recognition. In contrast to the classical science it is now referred to as "mobile".

The notion of stress, put forward by the Canadian pathologist Hans Selye in 1936 and further developed by him for half a century, became part and parcel of the emerging model of evolution. Selye defined stress as a nonspecific response of the host organism to any strong effects associated with the restructuring of its defense systems. The main cause of nervous stress, he says, is deviation of any vitally significant parameter of the inner or outer medium from an optimal level, an event disturbing the homeostasis of the host. At moderate exposure stress evolves as a survival mechanism, stimulating a search for adequate defense reactions and behavioral forms.

Stress factors can act upon the genome directly, inducing its rapid, significant, and effective reorganization (genomic stress), realized with the participation of the same MGE. Dr. Ilya Arshavsky, the founder of Russian age-specific physiology, suggested in 1982 a probable common mechanism of such modification: the organism finds the needed modification of its physiology by itself and thereafter, an appropriate genetic base for it. Dr. Yuri Chaikovsky, a Moscow evolutionist (2003) supporting this idea, is sure that the cell with its system of hereditary memory is capable of responding to an environmental challenge by an active and orderly genetic search (by this term he denotes the making of new genetic texts) rather than "waiting" passively for a random adaptive mutation.

Dr. Golubovsky presented one of the possible schemes of the genetic search (2000). Stress increases the activity of genes in FC, causes their magnification (increase in their number) enhancing the probability of incorporation of their extra copies into ОС of somatic and sex cells.

Incorporation of ОС into the sex cell is realized step by step through several generations. At first, if stress pressure persists, the inheriting of the copies is unstable, but it becomes consistent after 5 - 7 generations. The process is of directed and definite nature.

Systemic mutations, postulated by Richard Gold-schmidt, a German geneticist (1940), and Albert Dalk,

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Some of the structures and organs engendered by systemic mutations.

a Belgian embryologist (1949), had remained merely theoretical assumptions, until Vladimir Stegnii, a Tomsk geneticist, detected them in malarial mosquitoes in 1979. They led to the transformation of the ovicell architecture and were manifested by changes in the chromosomal-membrane relations and in the chromocenter status.

The genome architecture heterozygocity* was never noted, this indicating its exclusively saltational (jumpy) transformation.

It came out that the main causes of systemic mutations reside in the upset homeostasis of the organism and the environmental ecosystem, largely of the latter (particularly at extreme temperatures). Under these conditions a population shifts to closely-related reproduction; MGE are activated in it, mutagenesis is intensified, and in 1 - 2 generations the population becomes homozygotic in all chromosomes and gene loci, and a new species is born. As for variation and epigenetic variability, we can suggest with good probability that this arises with the participation of a mechanism similar to immunogenesis.

Modern science will rather deny any creative role of natural selection and its significance as an evolution factor (Golubovsky, Korochkin, Chaikovsky, Vandel (French zoologist), Lima-de-Farfa (Swedish ontogeneticist)). This conclusion is the direct result of the fact that the assumption on interspecific competition and the struggle for existence-from which the selection theory had been deduced previously-was not confirmed. A book by the author of this paper** offers numerous arguments and facts at variance with the selection concept and the selectionalism doctrine in general. The detection of the monomorphic species-specific part of the genome makes it clear that the population genetic processes in elementary populations are absolutely unrelated to evolution and hence, can no longer be regarded as anything related to natural selection, which is thus devoid of its substratum.

Since the end of the 1960s, a new viewpoint has been gaining ground: that special characteristics of complex systems cannot be explained by those of their components; advanced by a group of Russian scientists (Yuri Vyatkin, Aleksei Mamzin, Kirill Khailov, Yuri Chernov), this ecologist approach made its way into the theory of evolution. The new concept came to be regarded as tantamount to a recognition of the organizing and transforming effect of a higher system on that of a lower level. In other words, according to STE, the evolution coil starts uncoiling from the lowest elementary level-from random mutations modifying the genetic composition of a population and then presumably ushering in species formation and emergence of groups of a higher taxonomic rank.

* See: V. Nazarov, "Evolution Not According to Darwin. Change of the Evolution Model", Moscow, KomKniga, 2005. 520 pp. (in Russian).

** Heterozygote - a cell or organism whose homologous chromosomes carry different forms (alleles) of this or that gene in their hereditary set (genotype). - Auth.

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This causality vector can be called "ascending", and the very process described as coming "bottom up".

Events in the theory reflecting the systematism philosophy take the opposite course. The first impulse to evolutional changes appears in the higher system, "Sun-Earth"; it is picked by the biosphere as a lower system, and then by its components-certain biocenoses, which, in turn, induce component species to change. This vector of evolutional causality can be called "descending", and the very process described as coming "from above". In this case, naturally, the sphere of randomness contracts significantly.

Geological evidence indicates this very order of evolutionary events on our planet. Paleontological findings prove that the moments of biospheric crises and dramatic changes of the biota in the crucial periods of the Phanerozoic (taking 570 mln years) are in general in good correlation with the periods of geological crises and with the climatic and solar cycles (30 and 180 mln years, respectively). According to the data obtained by the USA paleontologists David Roup and Jack Sepkoski (1984), nine clear peaks of extinction were recorded in the geological history of the latest 250 mln years, following with distinct periodicity: 26 mln years in the Mesozoic (230 - 67 mln years ago) and the Cenozoic (beginning 60 - 70 mln years ago) and 34 mln years in the Paleozoic (570 - 230 mln years ago). The birth of new orders of animals in the Phanerozoic, as presented by Valentin Krasilov, a Moscow paleobiologist (1986), also corresponds to this periodicity.

Yet another important bit of evidence. It is as good as proved that life first emerged on the Earth initially not in the form of individual protoorganisms but in communities (primitive procaryotic systems). We can refer to the authority of Acad. Georgi Zavarzin, a microbiologist, in this connection (1979, 1984).

I am sure that new manuals and handbooks will describe the evolutionary process in this very sequence, starting from changes in higher systems. This will be a general theory of development of all living things, in which species formation proper will occupy an adequate place in the biological hierarchy.

In Russia the ecosystem theory of evolution (ETE) was first advanced by Valentin Krasilov (he called it a hypothesis) in 1969. In his opinion periodic fluctuations in the terrestrial orbit parameters, in the rotational axis and parameters trigger radical evolutional transformations in the biosphere. They inaugurate changes in the climate and activate tectonic processes, which function as a mechanism triggering destabilizing events in ecosystems and creating a stress (critical) situation in them. This is supplemented by alteration in the Earth's magnetic field polarity, to which all living organisms are particularly sensitive. An evolutionary phase, which V. Krasilov calls incoherent (discordant), thus sets in.

Major negative changes, described in common ecological terms, take place in ecosystems during this phase: the best adapted (dominant) forms die out instead of surviving, the succession ceases instead of continuing, the individual life span shortens instead of being prolonged, all this in parallel with high mortality of pioneer species. Biological productivity falls off, while the dead mass increases.

However, a basis for future progress is formed during these critical periods. The weakening of interspecific competition creates conditions for evolutional experimenting based on genetic search and a steep increase in the scale of variability. Viable monsters (such as stegosaurians or pteranodons) are born in such periods; their emergence during the coherent evolutionary phase (in stable ecosystems) would be far less likely. It is important to realize that an evolutionary experiment involves not just separate species, but their majority in a particular community at once, and as a result, the composition of the community is renovated after the crisis. In fact, it will be a new ecosystem. Judging by the paleontological data, so it was on the eve of the Silurian (beginning 440 mln years ago), the Carboniferous (beginning 350 mln years ago), the Jurassic (190 - 195 mln years ago), and the Cenozoic (60 - 70 mln years ago).

On the largest scale such events took place in the periods of biotic crises and in the incoherent evolutionary phase: the appearance of eucaryotic cells, multicellularity, separate genders and sexual reproduction, structurality, warm-blooded organisms, flower, placenta, intelligence, and hence, the coming to be of new types of organization. It seems that new higher taxa supplant the extinct ones. Documented study of critical events in the history of the Earth and its biosphere is truly an innovative approach in latter-day science.

Neither classical nor modern Darwinism with its predilection for the philosophy of uniformism showed interest in crises. Its adepts saw nothing qualitatively specific in them and were prone to regard evolution as a process running without major breaks and revolutionary shocks. This is yet another methodic error.

All this may convince the reader that the old neo-Darwinian model of biological evolution, incompatible as it is with the new empirical basis and scientific realities of the 21st century, should be abandoned. It should be replaced by the ecosystems theory of evolution despite so many blank spots in it.