Evolutionary saltations and evolution

The term saltation is a composite notion covering different categories of supposed saltational evolutionary changes. One can distinguish interspecies, macroevolutionary and morphofunctional saltations corresponding to saltational arising of a new species, of general Bauplans of new macrotaxons, and of large-scale morphofunctional alterations (irrelevant to any taxonomic aspects). Current data confirm the possibility of interspecies and mophofunctional saltations as relatively rare modes of evolutionary changes. Morphofunctional saltations result in the arising of macromorphoses that can sometimes stimulate the beginning of macroevolutionary typogenesis. Saltationism extremely exaggerates the evolutionary role of saltations, considering these to be the main factor of speciation and macroevolution. However, saltations are only peculiar and relatively rare form of hereditary variability representing elementary evolutionary material. Natural selection is the principal evolutionary mechanism that produces new adaptations and integrates different systems of the organism in the process of typogenesis. The arising of general Bauplans of new macrotax by means of macroevolutionary saltations seems to be improbable.     

Problems of Macroevolution (Molecular Evolution, Phenotype Definition, and Canalization) as Seen from a Hierarchical Viewpoint

As seen from a hierarchical viewpoint, macroevolution is neithera functional process nor a series of events in the past. Itis a record only. For this reason macroevolutionary laws areall statistical laws. Natural selection is a process that operates from one generationto the next at the population level in the hierarchy. Yet structuresat the organism level are found to "evolve." It is possibleto formulate only a tautological form of the concept of naturalselection at the population level alone; the bridge betweenlevels in this case is the phenotype. The phenotype (i) existsat the boundary between the organismic and population levelsof the hierarchy; (ii) is a functional manifestation of theinteraction between the genotype and the local environment onlyduring the period of a single generation; (iii) should ideallybe defined so as to exclude traits not reviewed by natural selection;(iv) is factorable into many individual functional traits ifone views viability selection as being instituted by a sequenceof environmental catastrophes, each of which emphasizes a particularset of traits as being temporarily important to survival. It is reemphasized that the action of natural selection on continuouslydistributed, nonpolymorphic traits curtails variability in proportionto the intensity of selection. The necessity for coadaptationwithin the organism imposes a bell-shaped curve upon survivingvariability. Canalizing selection is proposed as the processthat modifies these bell-shaped curves into lognormal parametricdistributions. It is also proposed that the per cent variabilityof the sample populations can serve as a measure of the intensityof natural selection (normalizing and directional together)that has most recently been acting upon the traits in questionin the populations used to establish the parametric distributions.     

Experimental approach to the hypotheses of heterochronic evolution in lower vertebrates

Heterochronies, temporal changes in ancestral ontogeny, are proposed to play the major role in microand macroevolutionary transformations of lower vertebrates. However, the evolutionary role of heterochronies often remains hypothetical, not verified experimentally. In the present paper, participation of heterochronies in (1) the origin of lacustrine fish species flocks, (2) the diversification of skeletal morphology in teleosts, and (3) the skull evolution in amphibians is experimentally verified. For this purpose, the temporal parameters of ontogeny were directly changed via artificial alterations of the thyroid hormones level in different representatives of lower vertebrates. The data obtained indicate that heterochronies are among the main mechanisms responsible for the current morphological diversity displayed by lower vertebrates at different phylogenetic levels.     

Challenge to the Specialist: Abraham Trembley's Approach to Research on the Organism--1744 and Today

We define an organismic biologist as one whose research is focusedprimarily on a single organism, or group of related organisms,and who investigates virtually the whole of nature as livedby that organism. We contrast an organismic biologist with aproblem-oriented biologist, that is one who uses an organism,or a group of organisms, in order to investigate a particularquestion. In our view, the consummate organismic biologist hasan outlook that allows her or him to conduct research on organismswith an open eye, to follow the cues offered by the organism,and to switch and learn new disciplines when the challenge tounderstanding the particular organism leads the investigatorin those directions. We provide examples of the organismic approachof Abraham Trembley working in the eighteenth century and ofthe senior author working in the twentieth century. Both focusedtheir investigations mostly on the freshwater hydra. While studyinghydra, Trembley demonstrated that: (a) complete animals canregenerate from small, cut pieces of those animals; (b) animalscan reproduce asexually by budding; (c) tissue sections fromtwo different animals of the same species can be grafted toeach other; (d) the materials oozing out of the edges of cuttissue have properties that fit the definition of protoplasmas described by Dujardin one hundred years later; (e) livingtissues can be stained, and those stained tissues can be usedin experiments; and (f) "eyeless" animals can exhibit a behavioralresponse to light. Some of the topics investigated in hydraby the senior author and his students are: (a) behavioral responsesto the peptide reduced glutathione and to tryosine; (b) mechanismof activation of the receptor to glutathione; (c) migrationof nematocytes; (d) algal-animal endosymbiosis; (e) an unusualdisulfide-linked collagen of nematocyst capsules; (f) componentsand action of nematocyst venom; (g) intracellular digestionof radioactive protein; (h) composition of and role in cellularadhesion of the mesoglea; and, (k) a developmental mutant androle of nerve cells in promoting budding. We conclude with aproposal for one way to train future organismic biologists atthe graduate and post graduate levels. This proposal grew outof our perception of the need to provide environments that nurturescientists who, by studying organisms, will find and definenew experimental systems for the next waves of biological discoveryyet to come when the specialists begin to investigate even moreintensively the interactions between cells, tissues, organisms,and communities. Specifically, we propose that on the campusesof several major universities having a broad range of graduateprograms, there be established year-round Institutes for OrganismicMarine Biology focused on the investigation of organisms notpreviously amenable to systematic experimentation. We believethat if America's biology is to remain vibrant and innovative,organismic biology should be an integral component in any longterm planning for research and training in the biological sciences.     

The Genetic Explanation of Vertical Evolution

The genetic theory of natural selection proposed by Fisher takes into account differential reproduction success of organisms, which may be estimated by using the Malthusian parameter as fitness. However, the minimum possible value of this parameter depends on ecological stability of an organism, which determines the probability of the survival and participation in reproduction for each viable offspring. In the course of vertical evolution, leading to an increase in the level of biological organization, ecological stability of organisms increases, and this might be accompanied by a decrease in their fitness. In the macroevolutionary process, alterations in ecological stability of organisms, including those responsible for an increase in the level of biological organization, are basic and primary changes whereas alterations in fitness are additional and secondary.     

Entropy and information in evolving biological systems

Integrating concepts of maintenance and of origins is essential to explaining biological diversity. The unified theory of evolution attempts to find a common theme linking production rules inherent in biological systems, explaining the origin of biological order as a manifestation of the flow of energy and the flow of information on various spatial and temporal scales, with the recognition that natural selection is an evolutionarily relevant process. Biological systems persist in space and time by transfor ming energy from one state to another in a manner that generates structures which allows the system to continue to persist. Two classes of energetic transformations allow this; heat-generating transformations, resulting in a net loss of energy from the system, and conservative transformations, changing unusable energy into states that can be stored and used subsequently. All conservative transformations in biological systems are coupled with heat-generating transformations; hence, inherent biological production, or genealogical proesses, is positively entropic. There is a self-organizing phenomenology common to genealogical phenomena, which imparts an arrow of time to biological systems. Natural selection, which by itself is time-reversible, contributes to the organization of the self-organized genealogical trajectories. The interplay of genealogical (diversity-promoting) and selective (diversity-limiting) processes produces biological order to which the primary contribution is genealogical history. Dynamic changes occuring on times scales shorter than speciation rates are microevolutionary; those occuring on time scales longer than speciation rates are macroevolutionary. Macroevolutionary processes are neither redicible to, nor autonomous from, microevolutionary processes.Authorship alphabetical     

Genetic explanation for vertical evolution

The genetic theory of natural selection proposed by Fisher takes into account differential reproduction success of organisms, which may be estimated by using the Malthusian parameter as fitness. However, the minimum possible value of this parameter depends on ecological stability of an organism, which determines the probability of the survival and participation in reproduction for each viable offspring. In the course of vertical evolution, leading to an increase in the level of biological organization, ecological stability of organisms increases, and this might be accompanied by a decrease in their fitness. In the macroevolutionary process, alterations in ecological stability of organisms, including those responsible for an increase in the level of biological organization, are basic and primary changes whereas alterations in fitness are additional and secondary.     

The logical structure of irreversible systems transformations: A theorem concerning Dollo's law and chaotic movement

The argument of historical irrevocability as an explanation for the irreversibility of organismic evolution is reconsidered. It is examined under which conditions a chain of transformations never can lead to a state equivalent to a previous one. It is shown to be sufficient to take into consideration that the environment of an organ also consists of the other organs in an organism. Under this prerequisite it is impossible to reach an ancestral state once more. This type of irreversibility depends solely on the mutual interdependency of characters within one organism. No reference to statistical arguments is necessary. The relationship between chaotic dynamic systems and the present theory is discussed.     

"I'll see it when I believe it!"*: Investigating Nervous System/Reproductive System Interactions in Animal Organisms

From the time of August Weismann's characterization of fundamentaldifferences between the role of the reproductive system (topreserve the "immortal" germplasm) and the other, somatic tissuesof the organism (to maintain the organism) biologists have inheritedan interesting organismic conundrum. How, indeed, are we tounderstand the relationship between the somatic systems (especiallythe nervous system—that characterize the animal organism)and the reproductive system, within that organism? In this paperit is argued that: (1) neuron-gamete-organism interactions areessential, organismic phenomena that have scarcely begun tobe investigated; (2) with reference to at least three differentkinds of animals it is possible to determine developmental,structural, functional and behavioral relationships betweenthe (species-oriented) reproductive systems, and the (individual,organism-oriented) nervous systems of those animals; and (3)results of such investigations make sense only in terms of thepeculiar evolutionary history and environmental adaptationsof specific kinds of animal organisms.     

Die revision des evolutionsdenkens

The criticism ofJ. Remane concerning the organism-centred conception of evolution is refuted. By referring to some strategic quotations most of the criticism can be shown to be based on an inadequate understanding of the criticized theory. It is shown that very recent attempts to base the theory of evolution on the competition of energy converting organismic systems must inevitably lead to a revised understanding of selection which encompasses internal, energetic, and environmental aspects. Consequently, phylogenetic transformation has to be conceived as a process that follows internal and external constraints. Malfunctioning organisms and abnormal ontogenetic stages testify internal organismic constraint as an indispensable component of the internal aspect of selection.     

Initial morphological diversity as a criterion in deciphering turbellarian phylogeny

The most profound structural variety in morphofunctional systems and morphogenetic mechanisms, i.e. the highest morphological diversity, is observed in those groups where these systems and mechanisms are evolutionarily most primitive. Here, such variety can involve the basic body plan of a given phylum and the types of morphogenesis characteristic of it. This correlation provides a new criterion of evolutionary primitiveness, namely, the criterion of initial morphological diversity.The highest morphological diversity among turbellarian groups is observed in the order Acoela. Acoel turbellarians are archaic in most of their features, apparently being a group near the base of the turbellarian phylogenetic tree. Among other turbellarians there are a few groups that also are archaic in some few features (above all, the Catenulida), although on the whole they are more advanced than the Acoela. The Turbellaria as a whole is notable for its morphological diversity in comparison with other classes of the Scolecida.     

Effects of thyroid hormone level alterations on the Weberian apparatus ontogeny of cyprinids (Cyprinidae; Teleostei)

Effects of thyroid hormone (TH) level alterations on the development and definitive morphology of the Weberian apparatus (WA, morphofunctional complex, providing transmission of sound signals from the gas bladder to the labyrinth of inner ear) were experimentally assessed in cyprinid fishes (Labeobarbus intermedius and Danio rerio). Alterations of TH-level were shown to lead to heterochronies, changes of timing and rates of ontogenetic events resulting in changes of definitive morphology of some structures as well as of the WA as a whole. Differences in reaction of WA structures to the TH-level alterations, and inter- and intraspecific variability of TH-responsiveness were revealed.     

Histochemical and cytologic changes in the liver in experimental poisoning and subsequent pregnancy]

In 275 white rats chronic intoxication was produced by injection of amidopyrine acetaldehyde and chloraldehyde derivatives for 4 months. Histochemical and electron microscopic investigations of the liver under the experimental conditions and subsequent pregnancy revealed certain changes in nucleic metabolism, glycogenolisis, in the content of sulfhydryl, disulfide, carboxylic groups of protein molecules. Decrease in activity of enzymes of Krebs cycle and pentosophosphate cycle proved the deep changes in hepatocytes at the level of oxidation-reduction processes and protein synthesis. Ultramicroscopic changes in the nucleus, in cytoplasmic network, mitochondria and local degenerative alterations determined the level of morphologic reconstructions in connection with the intoxication. As the liver performs a number of vital functions and is closely connected with regulatory systems of the organism, morphofunctional shifts in the organ affect unfavourably the system mother--fetus.     

Organismic supercategores: II. On multistable systems

The representation of biological systems in terms of organismic supercategories, introduced in previous papers (Bull. Math. Biophysics,30, 625–636;31, 59–70) is further discussed. To state more clearly this representation some new definitions are introduced. Also, some necessary changes in axiomatics are made. The conclusion is reached that any organismic supercategory has at least one superpushout, and this expresses the fact that biological systems are multistable. This way a connection between some results of Rashevsky’s theory of organismic sets and our results becomes obvious.     

Resistance to heavy metal toxicity in organisms under chronic exposure

The rate of changes of heavy metal ions concentrations in the organism or biological system will determine the choice of strategy of realization of heavy metal ions effect and, consequently, the biological effect itself. Which of the possible strategies will dominate, depend on the rate of changes of concentration of heavy metal ions in biological systems, functional activity of organism at the moment of metal action and on metals chemical properties. Keeping this view, the present review deals with the concept of time-based alterations of concentration of heavy metal ions (TACMI) in biological systems. On the basis of TACMI concept formation of organism resistance to metal ions action could be explained. In the event of slow increase of its concentration in organism, it produces induction of metallothioneins, other stress-proteins and relative changes in the whole metabolic system. This, first of all, results in formation of new specific epigenotypes, which provide higher resistance (hormesis effect) not only to metal ions that induced this effect, but also to such stress-factors as high temperature (at least, for micro-algae cells).     

Sex and destiny: The role of mating signals in speciation and macroevolution

A growing body of research posits a central role for mating signals in speciation and the reproductive isolation of species, yet there has been relatively little consideration of mating signal evolution within macroevolutionary theory. Factors that influence the divergence of fertilization systems generally, and mating signals specifically, may incidentally influence rates of speciation and patterns of species sorting. Potential key processes include: genetic drift, natural selection (differential survival), selection for mate recognition, and sexual selection. This paper explores the integration of mating signal evolution into macroevolution and hierarchy theory, arguing that speciational patterns may frequently result from “effect sorting”; in which microevolutionary processes operating at the organismal level have macroevolutionary effects at the clade level. Preliminary evidence indicates that sexual selection is a widespread and potent evolutionary force that, together with other mechanisms, may have a large, though incidental impact on species sorting. The Mate Competition Hypothesis is here proposed to account for this possibility, postulating that heritable, clade‐specific variations in the intensity of sexual selection and the potential breadth of signal‐receiver systems contribute to divergent patterns of species‐richness. Several examples from the vertebrate fossil record are consistent with this hypothesis.     

Calcium ions and the nervous system plasticity

The nervous system is different from all other systems of the organism by extreme flexibility of the structural and functional properties of its elements. This unique feature of the nervous system can be best described as plasticity in a broad sense of the word. All forms of plastic changes in the nervous system functioning have common basic mechanisms, the changes at the free Ca2+ cytosol ions being the most important one. These "calcium signals" trigger an extremely complicated intracellular machinery capable of controlling the structural and functional properties of the nervous system during the whole life span. This review summarises data on the intracellular Ca2+ ions mechanisms controlling the developmental plasticity of neuronal elements, synaptic plasticity of the mature nervous system, and the decline of plastic capabilities with ageing.