On the position of parthenogenetic vertebrates in the evolutionary flow and the applicability of species concept to them

2021 ◽  
pp. 140-152
Author(s):  
Iryna Dotsenko

The review is devoted to the analysis of literature sources considering the concepts of "species" and its criteria, "speciation", "reticulate evolution" and "Darwinian evolution", "divergence", "hybridization", and "parthenogenesis". The evolutionary fate and place of parthenogenetic organisms (in particular, among vertebrates) in the general evolutionary flow are considered. The reasons for the predominance of bisexual reproduction despite the obvious energetic and quantitative benefits of parthenogenesis are analysed. The applicability of the term "species" to parthenogenetic organisms is considered, considering their discrepancy with the main (genetic and reproductive) species criteria according to most concepts.

Author(s):  
Charles Clarke ◽  
Jan Schlauer ◽  
Jonathan Moran ◽  
Alastair Robinson

Nepenthes is a genus of 130-160 species, almost half of which were described after 2001. The recent, rapid increase in species descriptions has been driven by application of a less rigorous species concept by botanists, taxonomic inflation, and discoveries of new taxa during explorations of remote parts of Southeast Asia. Many recently published species descriptions of Nepenthes are based entirely upon qualitative morphological information and are not supported by adequate research. Accordingly, the status of many Nepenthes taxa is contested. Evolution within the genus is not well understood, because nuclear and maternally inherited plastid genomes cannot resolve relationships between many species, particularly those that evolved recently through introgression or reticulate evolution. Improvement in our understanding of the systematics and evolution of Nepenthes requires the adoption of ‘best practice’ collection and preservation methods, and the application of quantitative analytical methods for morphological, genetic, and ecological information.


2020 ◽  
Vol 69 (5) ◽  
pp. 1033-1038
Author(s):  
Bernhard Seifert

Abstract The Gene and Gene Expression (GAGE) species concept, a new version of the Pragmatic Species Concept of Seifert (2014), is proposed as a concept applicable to any described recent or fossil eukaryotic organism independent from its mode of reproduction or evolutionary history. In addition to presenting the concept as such, the article also provides practical recommendations for taxonomists when delimiting species and describing taxa. The wording of the new concept contains a heading core sentence plus five attached sentences addressing essential conditions for its translation into a sound taxonomic practice: “Species are separable clusters that have passed a threshold of evolutionary divergence and are exclusively defined by nuclear DNA sequences and/or their expression products. Nuclear DNA sequences and their expression products are different character systems but have a highly correlated indicative function. Character systems with the least risk of epigenetic or ontogenetic modification have superior indicative value when conflicts between character systems of integrative studies arise. All character systems have to be described by an adequate numerics allowing cluster formation and determination of thresholds. Thresholds for each character system should be fixed by consensus among the experts under the principle of avoiding oversplitting or lumping. Clusters must not be the expression of intraspecific polymorphism.” Recognizing the distortions and conflicts caused to taxonomy through barcoding or through assessment on the basis of association with other organisms, the GAGE species concept strongly downgrades the use of cytoplasmic DNA of endosymbiotic origin (mtDNA, cpDNA) or DNA of closely associated microbes (e.g., Wolbachia bacteria) for final taxonomic decision-making. Recognizing the distortion of phylogenies by the high frequency of reticulate evolution, it is argued that delimiting and naming species has to be separated from constructing bifurcating phylogenetic trees. [Cytoplasmic DNA; lumping; nuclear DNA; numeric taxonomy; oversplitting; reticulate evolution.]


2003 ◽  
Vol 68 (1) ◽  
pp. 139-177 ◽  
Author(s):  
Vladimír Kvasnička ◽  
Jiří Pospíchal

A simplified model of Darwinian evolution at the molecular level is studied by applying the methods of artificial chemistry. A chemical reactor (chemostat) contains molecules that are represented by binary strings, the strings being capable of replication with a probability proportional to their fitness. Moreover, the process of replication is not fully precise, sporadic mutations may produce new offspring strings, which are slightly different from their parent templates. The dynamics of such an autoreplicating system is described by Eigen's differential equations. These equations have a unique asymptotically stable state, which corresponds to those strings that have the highest rate constants (fitness). Fitness of binary string is calculated as a graph-theory similarity between a folding (phenotype) of respective string and the so-called required folding. The presented method offers a detailed view of mechanisms of the molecular Darwinian evolution, in particular of the meaning and importance of neutral mutations.


Author(s):  
Aaron M. Ellison ◽  
Lubomír Adamec

The material presented in the chapters of Carnivorous Plants: Physiology, Ecology, and Evolution together provide a suite of common themes that could provide a framework for increasing progress in understanding carnivorous plants. All speciose genera would benefit from more robust, intra-generic classifications in a phylogenetic framework that uses a unified species concept. As more genomic, proteomic, and transcriptomic data accrue, new insights will emerge regarding trap biochemistry and regulation; interactions with commensals; and the importance of intraspecific variability on which natural selection works. Continued elaboration of field experiments will provide new insights into basic physiology; population biology; plant-animal and plant-microbe relationships; and evolutionary dynamics, all of which will aid conservation efforts and contribute to discussions of assisted migration as the climate continues to change.


Author(s):  
Hans Hummer

Chapter 1 explores the modern values that have animated kinship studies since their emergence in the nineteenth century. It examines the sudden invention of kinship by Johann Bachofen, Henry Maine, John Ferguson McLennan, Numa Denis Fustel de Coulanges, and Lewis Henry Morgan in the 1860s, and the internal and external developments in the West that prompted their discoveries: revolutionary agitation, the engagement with “primitives” around the globe, industrialization and the disintegration of old solidarities, and intellectual revolutions in the study of prehistory, especially Indo-European studies and Darwinian evolution. Social theorists transformed kinship into an elemental form of human sociality and evolutionary development, and a building block of the emerging liberal order as the West coped with the ontological sea change wrought by the desacralization and industrialization of society.


1931 ◽  
Vol 65 (696) ◽  
pp. 5-18 ◽  
Author(s):  
E. B. Babcock
Keyword(s):  

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