Journal of General Biology

Vol. 63, No. 5, 2002

Life-history variation within a taxon: a comparative analysis of birds and mammals Yu. E. Romanovsky 371

Fluctuations in numbers in box populations of Drosophila and genetic mechanism of their regulation G. V. Grechany, V. M. Korzun, K. L. Kravchenko 382

Patterns of intraspecific variability in daces: ecological factors and pathways of phenotypic transformation A. V. Kozhara 393

Relationship between photosynthetic activity and assimilation of organic matter in marine plankton mixotrophic algae - the possibility of different metabolic strategies L. V. Ilyash 407

Changes in phytoperiphyton community during seasonal succession: influence of plankton sedimentation and grazing by Chironomid larvae V. B. Lukin 418

Evolution of tetrapod locomotion P. P. Gambaryan 426

Reviews

On book of Tomas Yunker and Uve Hossfeld "Discovery of evolution. Revolution theory and its history" I. Yu. Popov 446

Life-history Variation Within a Taxon: a Comparative Analysis of Birds and Mammals

Yu. E. Romanovsky

Department of General Ecology, Biological Faculty, M.V. Lomonosov Moscow State University, Moscow 119899, Russia

Most studies on life-history evolution discuss the necessity of distinguishing between extrinsic and intrinsic sources of variability in life-history traits. I use log/log plots of yearly neonate production in daugters (h) versus adult mortality () for 75 bird species and 88 mammal species to compare graphically life-history "fields" arranged by these selective forces along a "slow-fast continuum". Under the assumptions of steady-state and linear relationship between adult mortality and reproductive effort, as well as between juvenile survival and relative neonate weight, it is possibe to place additional axes in the two-dimentional plot, and to predict covariations among demographic and individual growth traits. The functional regression analysis shows, that the assumptions are completely fulfilled, at least for birds, but mammals show nonlinear relationship between adult mortality and reproductive effort. This can be explained by peculiarities of metabolism and parental care in small mammals with high reproductive output. Hence, for birds the axis of relative neonate weight approximately coincides in direction with the juvenile survivorship axis, but this is not a case for mammals. In both taxa, the relative neonate weight is an invariant in relation to fecundity and adult mortality (but not in relation to adult body weight). This important feature, together with other intrinsic (energetic and phylogenetic) constraints, explains well-documented close covariations among traits, even when the effect of body size is factored out. It is argued that life-history and body size variations in birds and mammals mainly depend on a pattern of temporal resource deficiency, although this impact cannot be separated from that of extrinsic juvenile mortality.

Fluctuations in Numbers in Box Populations of Drosophila and Genetic Mechanism of Their Regulation

G. V. Grechany, V. . Korzun, K. L. Kravchenko

Institute of Biology, Irkutsk State University, box 24, ul. Lenina 3, Irkutsk 664003, Russia

e-mail: root@bio,.isu.runnet.ru

Box populations of Drosophila melanogaster are characterized by two types of periodical fluctuations of numbers: with low and high frequency. High frequency fluctuations are determined by existence of preimago and imago stages and subsequent delay in density-dependent limitation of imago reproduction, duration of which is determined by time of preimago stage. The period of these fluctuations should be limited within two generation, that is confirmed by experimental data. Low frequency fluctuations with the period of 13-15 generations are the result of ecological density-dependent effect. In this case during pick density one can observe continuous degradation of population (i.e. decrease in fecundity and life time of imago) and following decrease in numbers. Temporary changes in fecundity of females and their offspring of the second generation are positively correlated with low frequency fluctuations in numbers. Such relationhips show the possibility of density-dependent, cyclic, genetic changes in fecundity connected with fluctuations in numbers. It means that at the phase of growth in numbers when the density is still low, the selection is directed to the individuals with high fecundity sensible to overpopulation. The phase of decline in numbers is connected with high density and selection directed to the individuals with low fecundity in low density populations. The changes in genetic structure of fluctuating population lead to the weakening of this fluctuations and to the maintaining of population under such conditions.

Patterns of Intraspecific Variability in Daces: Ecological Factors and Pathways of Phenotypic Transformation

A. V. Kozhara

Institute of Biology of Inner Waters, Russian Academy of Science. Borok, Nekouzsky raion, Yaroslavskaya oblast 152742, Russia

e-mail: ko:hara@ibiw.yaroslavl.ru

The inverstigation of geographical and ecological variations of wide-spread species of daces allows to reveal regular patterns of phenotypic transformations with limited number of their possible ways. The set of characters involved and the directions of their changes are specific for both examined taxa and putative factors of subspeciation. Two basic groups of evolutionary and ecological situations leading to the intensive intraspecific divergence are considered: living or spawning in brackish water and heavy anthropogeneous pollution. Striking morphological similarity was found between populations from zones of hydrochemical anomalies and some remote populations inhabiting non-polluted fresh water bodies. The author discusses possible nature of these isomorphisms and cases of regular phenotype transformation and their implications for microevolutionary and systematic studies in fish. The data obtained suggest key role of water mineralization in evolution of the subfamily of dace fish.

Relationship Between Photosynthetic Activity and Assimilation of Organic Matter in Marine Plankton Mixotrophic Algae - the Possibility of Different Metabolic Strategies

L. V. llyash

Dept. Hydrobiology, Biological Faculty, M.V. Lomonosov Moscow State University, Vorob'evy Gory, Moscow 119992, Russia

e-mail:ilyash@2. hydro.bio.msu.ru

The relationship between photosynthetic and heterotrophic activities of plankton mixotrophic algae is characterized by the type of metabolic strategy. Algae with a primary photoautotrophic strategy grow at the expense of photosynthesis without uptake of organic substrates when inorganic and organic nutrients are available. They assimilate only organic substrates when inorganic nutrients are in shortage, while heterotrophic activity supports photosynthesis under conditions of inorganic nutrients deficiency. Algae with a primary heterotrophic strategy grow heterotrophicaly under repletion of inorganic and organic nutrients. Photosynthesis occurs only when organic substrates are depleted. The most mixotrophic algae combine the features of a primary photoautotrophic and a primary heterotrophic strategies. The varieties of metabolic types of mixotrophic algae form a continuum with a primary photoautotrophic strategy on the one end and a primary heterotrophic strategy on the other. The natural conditions allowing mixotrophic algae to use one or other metabolic strategy are determined by the dynamic of inorganic and organic nutrients.

Changes in Phytoperiphyton Community During Seasonal Succession: Influence of Plankton Sedimentation and Grazing by Chironomid Larvae

V. B. Lukin

Department of General Ecology, Biological Faculty, M.V. Lomonosov Moscow State University, Vorob'evy Gory. Moscow 119899, Russia

The investigation of seasonal changes in spatial structure of phytoperiphyton during succession was conducted at the lower reaches of Akulovsky water channel from April to August 2000. At the beginning of succession from April to June dominant forms were chain-forming diatoms and filamentous green algae, sedimented from plankton. Later, at the middle of June under increasing pressure of herbivorous, they were replaced by stretched unicellular diatoms and colonial cyanobacteria. In late June-August, when herbivorous predation was the most intensive, the relative abundance of typical periphytonic forms decreased while that of settled planktonic forms increased. The effect of planktonic algae sedimentation on periphyton composition was evaluated as similarity between phytoperiphyton and phytoplankton communities measured with Chekanovski Sorensen index. The value of this index tends to decrease with the development of periphyton while showing some relation to intensity of herbivorous pressure. Minimal values of Chekanovski - Sorensen index were under moderate herbivorous density, wheras maximal values were observed in periods of extremely high or low herbivorous density.

Evolution of the Tetrapod Locomotion

P. P. Gambaryan

Zoological Institute Russian Academy of Sciences. Universitetskaya nab. 1, 199164 St. Petersburg, Russia

e-mail: gambar@PG5237.spb.edu

Fish-like ancestors of tetrapods did not need strong limb musculature because they inhabited waters and were practically imponderable. In the primitive tetrapods, principal function of the limbs was initially restricted to passive anchoring in the course of animal movements on the substrate by means of lateral bending of the body (undulation). However, progressive development of carrying function of tetrapod limbs lead to clearing the body off the substrate which reduced friction costs and made the tetrapods less dependent on the substrate properties. Along with this, the limbs became more important as the active locomotory organs. But at the beginning, this diminished locomotory speed as the momentum caused by undulation could no longer provide additional forward sliding.

Locomotory function of the tetrapod limb could be carried out due to both retraction and pronation at the shoulder joint. Relatively short humerus of the primitive tetrapods made it indifferent which of these two particular actions lead to elongation of the steps. In most of the recent tetrapods with sprawling limbs (Urodela, Lacertilia Sphenodontia, Crocodilia), step elongation was carried out mainly by retraction at the shoulder joint. Contrary to this, in Tachyglossidae (Mammalia: Monotremata) retraction is absent while pronation at the shoulder joint becomes the most important component of step elongation. This made it possible to recognize two principal types, pronatory and retractory, of locomotion on the basis of the main movement in the phase of support.

A mathematical model describing changes in step length during the phase of support in both of these types is elaborated. It takes into account relative sizes of stylopodium and zeugopodium, the angles of pronation and retraction at the shoulder joint, the angle of adduction at the elbow joint, and the angle of body undulation arc. It is shown on the basis of this model, varying of which of the above parameters is advantageous and which is disadvantageous in each of the locomotory types.

In the pronatory locomotory type, adduction (lateral mobility) at the elbow joint is employed. It leads to special changes in morphology of the elbow joint due to which humeral condyle becomes spherical .and promotes both adduction and rotation of the entire antebrachium. In the retractory locomotory type, amplification of pronation is to be limited in order to provide step elongation, so certain morphological adaptations occur in the elbow joint which prevent adduction at this joint.

For step elongation, retraction at the shoulder joint is usually more advantageous than pronation, therefore historical emergence of the pronatory type could be considered as inadaptive. However, transversal horizontal axis of rotation at the shoulder joint appeared to be a prerequisite of the subsequent appearance of the most perfect locomotion in the therian mammals with then" parasagittal limbs.

Transition to the parasagittal limb construction was associated with adaptation to jumping asymmetric locomotion. It caused elongation of the shoulder bone downward which lead to widening of rotation cone of the humerus and, at the same time, to reduction of the coracoid portion of the glenoid fossa, the latter became horizontal rather than lateral. As a part of this process, the longitudinal axis of the scapula was displacing caudally with destruction of the suture-like articulation of the acromion process with the clavicle. The latter became articulated with the sternum directly or via much reduced interclavicle (or via procoracoid rudiment). This increases amortisatory function of the shoulder girdle during landing at the final stage of jump.