Zhurnal obshchei biologii最新文献

There are known three groups of vertebrates, representatives of which are gifted in active flight, namely birds, bats, and pterosaurs. Among them, the group biologists and engineers are most interested in is birds. In essence, the flight of birds is considered as a basic type, with which other groups are to be compared when studying the flight of vertebrates or trying to reconstruct it. However, while aerodynamic principles are common for all groups due to environmental uniformity, biomechanical means of flying turn out to be dependent on the wing morphological features that evolved within a specific group. At that, as for birds and bats, there is a possibility for making direct observations of the flight and comparisons between presumable and actual states, while for pterosaurs such a possibility is lacking. So, the principles of pterosaurs' flight have to be reconstructed using only paleontological data on their wing morphology and evolution.

For the first time were the results of studies on influence of main kinds of local anthropogenic factors on soil emission of biogenic greenhouse gases (CO2, CH4, and N2O) in permafrost ecosystems of Arctic and North-Boreal zones of the Russian Federation, and also of the Spitsbergen Archipelag summarized. Different types of land use can, depending on their manner, lead to significant enhancing or suppression of soil CO2 emission. On average, anthropogenic factors (AFs), acting in concert, favor the enhancement of local CO2 soil emission, promoting, at the same time, an increase in its dispersion. AFs directly influence the microbial-root respiration in soil, modify the soil itself, and indirectly affect important natural respiration regulators, phytomass reserves in particular, which makes them primary factors with relation to respiration pattern. AFs influence also the emission of other biogenic greenhouse gases (CH4 and N2O), though this influence can be exercised in different ways. Methane emission is mediated by degree of the territory drainage. However, in all studied cases, AFs have led to source reduction or sink intensification of this gas from the atmosphere. Unlike methane emission, N2O emission increased under the influence of AFs considered. As for the whole complex of AFs that impacts the carbon balance and fluxes of CO2 in cryogenic ecosystems, its role is expressed through the enhancement of soil respiration at the beginning of the cold season, when AFs are capable of soil emission increasing, at the level of meso-landscape, almost by 50%.

Processed are 57596 dated series of tree-rings width (TRW ) from the International Tree-ring Data Bank. The results obtained indicate that: 1. The TRW is strongly correlated with tree age. Periods of cambium activity are strictly dependent on the age of the trees. Therefore, there is a strong correlation between TRW and periods of radial growth. It is suggested that synchronization of the periods of radial growth in the first 150 years of trees life with cycles of climatic factors leads to increase in TRW . 2. Satisfactory coincidence between latitudinal profiles of TRW , on the one hand, and climatic and biological indicators, on the other hand, is observed. Latitudinal profile of TRW gets its form under the influence of climate and assimilating mass productivity. 3. Latitudinal change of the TRW in the Cretaceous had a pronounced displacement of a maximum from equator toward 30 °NL. Growth gain of Cretaceous gymnosperms was about twice higher than that of modern trees. Such asymmetry of paleolatitudinal profile of TRW sharply distinguishes it from modern latitudinal profiles that follow climatic parameters.

The task to estimate the fitness of a clonal plant with polyvariant ontogeny reduces to compiling a life cycle graph, constructing and calibrating the corresponding matrix model of the discrete-structured population, and calculating the dominant eigenvalue (λ1) of the model matrix. We demonstrate a solution to this task with a sample of Calamagrostis epigeios , a perennial long-rhizome grass propagating vegetatively, and data on the age-stage structure of its local population. A traditional technique of successive censuses fixing the age-stage status of all individuals on a permanent sample plot (SP) provides for calculating frequencies of ontogenetic transitions directly from the data, but leaves uncertain the status-specific reproduction rates as the recruit parents are unknown (“reproductive uncertainty”). Uncertainty in data was leading to that in the estimation and dictating a need to change the method of field study: the description of above-ground parts of plants has been completed with the analyses of rhizome parent-daughter links revealed after digging SPs out. However, the traditional, fixed area of SPs (1 m 2) forced cutting the links off along its perimeter, while those within the SP turned out quite entangled already in a 4-year-old colony. A result, the reproductive uncertainty were not eliminated completely, and the next step in the method development has become to determine the contour of the entire woodreed colony and to carefully dig it out. Analysing both the above- and below-ground spheres of the colony has enabled us to calculate uniquely all the elements of the matrix model, hence the value of λ1, while accounting for the actual area of the contour in the current and previous years amends the value of λ1 needed for comparison with the results of previous studies.

We analyzed the occurrence of female song in different families of Passeriformes aiming to better understanding of evolutionary prerequisites of this phenomenon and its relation with species biological traits and patterns of main passerine groups dispersion. Examined are 18 complete families, two Turdidae subfamilies, and three Sylviidae subfamilies among songbirds, also 4 complete families and two Tyrannidae subfamilies among bronchophone birds. As the data obtained indicate, female singing had appeared independently in different Passeriformes families, both songbirds and bronchophone ones, and seems not to be ancestral for all birds of this order. We did not find any direct connection of female song phenomenon with sexual dimorphism, duet singing or lipochrome coloration.

Data are presented on the dynamics of phytomass and primary production of the undershrub-sphagnum bog. Comparison of productivity parameters in sites with unimpaired and bumt-out vegetation is used as a method of analysis of the phytocenosis functioning during its 6-year recovery after a fire. Net primary production varied from 4.9 to 9.6 tons/ha • yr in the unimpaired bog site and from 5.3 to 15.1 tons/ha • yr in the burnt-out one. By the end of the fifth year of recovery, the phytocenosis fully compensated the loss of carbon due to the fire, mainly at the expense of roots production. Recurrent fires have a result of more profound changes in phytomass structure and reduction of primary production.

In spite of reduction in atmospheric emission, current state of forest ecosystems within the impact zone of Severonickel enterprise still reflects the entire spectrum of anthropogenic digression stages. As the distance to the enterprise grows shorter, structural-functional changes in forest communities are manifested in dropping out of mosses and lichens, replacement of undershrub by Poaceae, worsening of timber stand and undergrowth conditions and their progressive dying-off, and, as a result, in forming of anthropogenic wastelands. Alterations of elemental composition of fir bark and needles due to exposure to pollutants consist in accumulation of nickel, copper, cobalt, arsenic, and sulfur along with depletion of calcium, magnesium, manganese, and zinc. According to the data obtained by correlation and multiparameter analyses, the accumulation of heavy metals in fir organs is closely related to the increasing of their concentration in root-inhabited soil layers as the distance to the pollution source is getting shorter. By comparison with the background fir grove, concentration of available compounds of nickel and copper in the ground litter of open fir-birch woodland near the enterprise increases by the factor of 30-60, reaching up 280 and 130 mg/kg respectively. With the increasing of anthropogenic stress, the ground litter becomes depleted of available calcium, magnesium, potassium, manganese, and zinc. For the first time, the coupled dynamics of vegetation and soil state in fir forests as a response to reduction in atmospheric emission is tracked back. The most distinguishable response to the reduction appears to be the development of small-leaved plants' young growth within the impact zone. For the last decade, concentration of nickel in fir needles and in ground litter has reduced by the factor of 1.2-2. As for copper, its concentration in needles has reduced by the factor of 2-4, though in ground litter remains the same. By comparison with the period of maximum emission at the edge of 1980-90s, in open fir-birch woodland near the enterprise the concentration of nickel and copper in needles has reduced by the factors of 2.5-6 and 7-12 respectively. This reduction of heavy metals concentration in fir needles is related mainly to diminishing of their emission from the atmosphere, although their stores, accumulated in soil during previous decades, still remain quite plentiful.

On the basis of maximum entropy method embedded in MaxEnt software, the cartographic models are designed for spatial distribution of 63 species of vascular plants inhabiting low mountain belt of the Tukuringra Range. Initial data for modeling were actual points of a species occurrence, data on remote sensing (multispectral space snapshots by Landsat), and a digital topographic model. It is found out that the structure of factors contributing to the model is related to species ecological amplitude. The distribution of stenotopic species is determined, mainly, by the topography, which thermal and humidity conditions of habitats are associated with. To the models for eurytopic species, variables formed on the basis of remote sensing contribute significantly, those variables encompassing the parameters of the soil-vegetable cover. In course of the obtained models analyzing, three principal groups of species are revealed that have similar distribution pattern. Species of the first group are restricted in their distribution by the slopes of the. River Zeya and River Giluy gorges. Species of the second group are associated with the southern macroslope of the range and with southern slopes of large rivers' valleys. The third group incorporates those species that are distributed over the whole territory under study.

For the plant species, which is considered a short-lived perennial, we have composed a scale of ontogenetic stages and the life cycle graph (LCG) according to annual observations on permanent sample plots in an Alpine lichen heath during the 2009-2014 period. The LCG that reflects seed reproduction has been reduced to the one that avoids the stage of soil seed bank, yet preserves the arcs of annual recruitment. The corresponding matrix model of stage-structured population dynamics has four stages: juvenile plants (including seedlings), virginal, generative, and 'terminally generative' (the plants die after seed production). Model calibration reduces to directly calculating the rates of transition between stages and those of delays within stages from the data of only one time step, while keeping the two reproduction rates uncertain, yet confined to the quantitative bounds of observed recruitment. This has enabled us to determine a feasible range for the dominant eigenvalue of the model matrix, i.e., the quantitative bounds for the measure of how the local population adapts to its environment, at each of the five time steps, resulting in aformally nonautonomous model. To obtain 'age-specific parameters' from a stage-classified model, we have applied the technique that constructs a virtual absorbing Markov chain and calculates its fundamental matrix. In a nonautonomous model, the estimates of life expectancy also depend on the time of observation (that fixes certain environmental conditions), and vary from two to nearly seven years. The estimates reveal how specifically short lives the short-lived perennial, while their range motivates the task to average the model matrices over the whole period of observation. The model indicates that Eritrichium caucasicum plants spend the most part of their life span in the virginal stage under each of the environment conditions observed, thus revealing the place retention strategy by C. K6rner (2003), or the delayed-development strategy by L.A. Zhukova (1995). We discuss the prospects of model experiments with a logically nonautonomous model to forecast the long-term dynamics of E. caucasicum under a scenario of climate changes.

The data revealed by comparative embryology of the basal (diploblastic) metazoans is traditionally considered a valuable potential source of information on the origin and early evolution of the animal kingdom and its major clades. Special attention is paid to the fundamental morphogenetic process of gastrulation during which the cells of the early embryo differentiate into the germ layers and the primary body plan is formed. Comparative analysis of gastrulation in different cnidarian taxa reveals high level of intergroup, intragroup, and individual variation. With few exceptions, there is no robust correlation between the type of gastrulation and the taxon. Current data do not support the idea that morphogenetic processes underlying cnidarian gastrulation can be divided into several distinct types. Rather, there is a continuum of equifinal ontogenetic trajectories. In cnidarians, the mode of gastrulation apparently depends less on the macroevolutionary history of the species than on various evolutionary plastic features, such as the oocyte size, the amount of yolk, the number of cells at the blastula (or morula) stage, the presence of phototrophic symbionts, or the ecology of the larva. Thus, in cnidarians, morphogenetic basis of gastrulation contains only a very weak phylogenetic signal and can have only limited application in phylogenetic reconstructions. On the other hand, comparative studies of the ontogeny of the basal metazoans shed light on the general rules of the evolution of morphogenetic processes that is crucial for understanding the early history of the animal kingdom.