Igor Popov

Ecological Value of the Sorokaoziorki Wetland Complex in the Steppe of Central Eurasia (Khakassia, Russian Federation)

The wetlands of Central Asia, including many of high ecological value, are poorly studied and poorly represented in international conservation activities. The Sorokaoziorki (“Forty Lakelets”) complex of wetlands, located in the arid Koibalskaya steppe (Republic of Khakassia, Russian Federation), falls into this category. We documented the origin of the complex’s wetlands, patterns of land use and economic activities, and use of the area by multiple bird, mammal, and fish species. The “lakelets” of the Sorokaoziorki originated from a dried river bed that refilled relatively recently with water introduced from irrigation activities. The resultant wetlands and surrounding wet grasslands within the Sorokaoziorki complex represent a refuge for wildlife, while the surrounding steppe has been turned to pasture. Located at a crossroads of bird flyways, at least 140 bird species use the Sorokaoziorki complex to nest or as a stop-over point during migration. Additionally, we documented the occurrence of seven fish, one lamprey, and seven mammal (including three bat) species within the complex. The planting of sea-buckthorn (Hippophaё rhamnoides) and the restriction of grazing around the edges of the wetlands in the Sorokaoziorki wetland complex has contributed to the conservation of this ecologically important area.

Climate Warming as a Possible Trigger of Keystone Mussel Population Decline in Oligotrophic Rivers at the Continental Scale

The effects of climate change on oligotrophic rivers and their communities are almost unknown, albeit these ecosystems are the primary habitat of the critically endangered freshwater pearl mussel and its host fishes, salmonids. The distribution and abundance of pearl mussels have drastically decreased throughout Europe over the last century, particularly within the southern part of the range, but causes of this wide-scale extinction process are unclear. Here we estimate the effects of climate change on pearl mussels based on historical and recent samples from 50 rivers and 6 countries across Europe. We found that the shell convexity may be considered an indicator of the thermal effects on pearl mussel populations under warming climate because it reflects shifts in summer temperatures and is significantly different in viable and declining populations. Spatial and temporal modeling of the relationship between shell convexity and population status show that global climate change could have accelerated the population decline of pearl mussels over the last 100 years through rapidly decreasing suitable distribution areas. Simulation predicts future warming-induced range reduction, particularly in southern regions. These results highlight the importance of large-scale studies of keystone species, which can underscore the hidden effects of climate warming on freshwater ecosystems.

“Laws” in Biology

Various “laws”, “regularities” and “rules” have been especially often found in palaeontology and biogeography. The adherents of the idea of directed evolution considered that these laws indicated the existence of order in the living nature similar to the order of chemical elements or the existence of internal forces driving evolution. On the contrary, authors opposing the concepts of directed evolution argued that there was no need to invent obscure internal driving forces since everything could be easily explained by the known evolutionary factors.

The Sources. Formation of the Concept of Directed Evolution in the Nineteenth Century

The pre-history of the concepts of directed evolution is represented by treatises of the authors who worked in the first half of the nineteenth century (Jean-Baptiste Lamarck, Georges Cuvier, Giovanni Batista Brocchi and others). They contained ideas related to spontaneous evolution, constraints on variation and the similarity of lifecycles of species and those of individuals. In the second half of the nineteenth century the concept of directed evolution was developed by Albert von Kolliker, Carl Nageli, Edward Cope, Alpheus Hyatt, Wilhelm Haacke and Theodor Eimer, who worked more or less independently of each other. Each of these authors can be credited with being, in some respect, the pioneer of orthogenesis. The first works dealing with directed evolution were disconnected, and we cannot find in them the first wording of this concept, however hard we might try. This elusive concept can be deduced from the context of the writings of several authors, who claimed that organisms changed spontaneously in definite directions and denied the leading role of natural selection. As for the rest, their ideas had little in common.

Orthogenesis and the Modern Evolutionary Synthesis

The modern evolutionary synthesis, also referred to as the modern Darwinism, was formed in the 1930–40s and has dominated biology ever since. Its success is partly due to the energetic claims of its authors that they had solved all the main problems of the evolutionary biology. The modern Darwinism was formed over a long period of time by many scientists. This circumstance was both its weakness and its strength. On the one hand, the vagueness of its main postulates left it open to criticism. On the other hand, so much was written about this theory that most critical remarks could be addressed by finding a reference to some concession, exception or particular case.

Declarations in Favour of Orthogenesis in the 1900–1930s

The ideas of directed evolution were especially popular in palaeontology. They were also supported by idealistic morphologists, who described “typological affinities” of biological structures without analysing either their origin or their adaptive significance. This analysis revealed morphological regularities, which were used as arguments in favour of orthogenesis. Some taxonomists, zoologists, botanists, geneticists, biochemists also supported orthogenesis at that time, criticising the adaptationistic paradigm and revealing certain laws of variation and evolution. Some of their arguments still seem convincing.

Adaptation or Non-adaptation?

The adherents of directed evolution claimed that adaptation to the environment was not the main driving force of evolution. Their opponents either denied instances of inadaptive evolution or insisted that adaptive changes were by far more numerous and therefore evolution in general was the creation of adapted organisms. Orthogeneticists objected that seemingly adaptive organs first evolved independently of the environment and then an organism put them to use. In this way, organisms adapted to their own structure. The phenomenon of senescence is a remarkable example of non-adaptive nature of characters.

Constraints on Variation

The actual number of variations is smaller than the expected one. There are no blue-eyed fruit flies, no viviparous birds or turtles, no hexapod mammals etc. Such observations provoke non-Darwinian evolutionary concepts. Darwin addressed the contradictions between his model of random variability and the existence of constraints but could not explain them convincingly. Modern Darwinism cannot not solve this problem, either, and the question persists.

Direct Impact of the Environment on Evolution and the Inheritance of Acquired Characteristics

Speculations about a direct effect of the environment on evolutionary changes are closely associated with orthogenesis because accusations of Lamarckism were have often been directed at its supporters. At the same time, the ideas of Lamarck and his followers were discredited by the idea of the “inheritance of acquired characteristics”. This seems to be a firmly established fallacy. Lamarck indeed wrote about exercises and action of the environment upon evolution but never used the terms “heredity” or “inheritance”.

Anticipation, Parallelisms and Convergences

Phylogenetic anticipation means that organs or their rudiments evolve at an early stage of a group’s evolution, disappear at the next stages and later re-emerge either as adaptations or as a mark of a new evolutionary stage. A similar phenomenon is the emergence of aristogenes, organs useless for an organism but creating preconditions for the origin of “useful” organs in its distant descendants. Unlike “anticipatory” features, they do not disappear in the immediate descendants but continue to evolve although their adaptive significance does not become apparent for a long time. Anticipations and aristogenes can be considered as a case of parallelisms and/or convergences, which have always attracted orthogeneticists.