5. Species and classification

2019 ◽  
pp. 63-82
Author(s):  
Samir Okasha
Keyword(s):  
Evolutionary Biology ◽  
Species Concept ◽  
Biological Species ◽  
Theory And Practice ◽  
Biological Species Concept ◽  
Phylogenetic Systematics ◽  
Species Problem ◽  
Higher Taxa ◽  
Linnaean System

‘Species and classification’ first considers the species problem and the biological species concept. It then discusses phylogenetic systematics, which involves the organization of species into higher taxa. Classification in science raises a deep philosophical issue as all objects can in principle be classified in more than one way. Is there a ‘correct’ way to assign organisms to species, and species to higher taxa? Classification of organisms was traditionally done using the Linnaean system, which served biologists well for years, and elements of it are still used today. However, the rise of evolutionary biology has led to fundamental changes in both the theory and practice of biological classification.

Discriminating arboviral species

2021 ◽  
Vol 102 (4) ◽  
Author(s):  
Yiyuan Li ◽  
Angela C. O’Donnell ◽  
Howard Ochman
Keyword(s):  
Evolutionary History ◽  
Viral Vectors ◽  
Species Concept ◽  
International Committee ◽  
Biological Species ◽  
Biological Species Concept ◽  
Substantial Variation ◽  
Artificial Boundaries ◽  
Human Infections

Mosquito-borne arboviruses, including a diverse array of alphaviruses and flaviviruses, lead to hundreds of millions of human infections each year. Current methods for species-level classification of arboviruses adhere to guidelines prescribed by the International Committee on Taxonomy of Viruses (ICTV), and generally apply a polyphasic approach that might include information about viral vectors, hosts, geographical distribution, antigenicity, levels of DNA similarity, disease association and/or ecological characteristics. However, there is substantial variation in the criteria used to define viral species, which can lead to the establishment of artificial boundaries between species and inconsistencies when inferring their relatedness, variation and evolutionary history. In this study, we apply a single, uniform principle – that underlying the Biological Species Concept (BSC) – to define biological species of arboviruses based on recombination between genomes. Given that few recombination events have been documented in arboviruses, we investigate the incidence of recombination within and among major arboviral groups using an approach based on the ratio of homoplastic sites (recombinant alleles) to non-homoplastic sites (vertically transmitted alleles). This approach supports many ICTV-designations but also recognizes several cases in which a named species comprises multiple biological species. These findings demonstrate that this metric may be applied to all lifeforms, including viruses, and lead to more consistent and accurate delineation of viral species.

Species

2021 ◽  
pp. 219-238
Author(s):  
Andrew V. Z. Brower ◽  
Randall T. Schuh
Keyword(s):  
Species Concept ◽  
Biological Species ◽  
Species Concepts ◽  
Biological Species Concept ◽  
Character State ◽  
Phylogenetic Species Concept ◽  
Units Of Analysis ◽  
Perceived Reality

This chapter studies the systematists' perspective on species concepts and the role of species in systematics. No matter how sophisticated the tools and methods enhancing the conceptualization of reality may become in the future, systematists will still be constrained by their perceptions. In their more modest, empirical view, systematists embrace their perceived reality and prefer species concepts that incorporate tools for identifying and delimiting species as empirical hypotheses, thereby providing them with efficacious working terminal elements for phylogenetic analysis and classification of more inclusive taxa. It is fortunate that cladists employed the notion of a “phylogenetic” species concept based on diagnosability before more metaphysically inclined authors appropriated the term for concepts founded on monophyly or common ancestors. As noted, Willi Hennig's species concept was a version of the “biological” species concept, and it fell to his followers to develop a species concept that is well suited to cladistic principles. Among the earliest of the post-Hennigian empiricists was American Museum ichthyologist Donn Rosen. Rosen's concept, sometimes called the apomorphic concept because of its requirement that every recognized species must have its own derived character state, accomplished two key advances for systematics: it proposed a cladistic criterion for recognizing species, and it defined species as the minimal units of analysis, as far as taxonomy is concerned, thus setting a lower bound for systematic inquiry.

scholarly journals Birds of Prey (Falconiformes, Accipitriformes) of Northern Eurasia in the Biological Tetranary Nomenclature

2020 ◽  
pp. 16-51
Author(s):  
Pavel V. Pfander ◽  
◽  
Keyword(s):  
Reproductive Isolation ◽  
Species Concept ◽  
Physical Object ◽  
Biological Species ◽  
Birds Of Prey ◽  
Northern Eurasia ◽  
Biological Species Concept ◽  
Species Problem ◽  
Nomenclature System ◽  
Definition Of

The main disadvantage of the generally accepted trinary system of around-species nomenclature is the lack of a species concept. This leads to the fact that any lower taxon can be declared a species or subspecies, and any combination of these taxa of arbitrary rank is correct and legitimate, by definition, and therefore cannot even be discussed. Ambiguity of the level of divergence of species creates a “species problem” and makes the question – species or subspecies – meaningless. The solution to the “species problem” can be the creation of a nomenclature system with a "own" species concept. The only concept whose criteria are objective (reproductive isolation and sympatry) and, more importantly, correspond to a certain level of divergence, and that have a biological meaning, is a biological species concept. However, the use of this concept is difficult due to the uncertainty of the degree of reproductive isolation. Therefore, a revised definition of a biological species (B-species) as a category of taxonomy is proposed – this is a level of divergence that provides reproductive isolation sufficient for sympatry (with other closely related forms). Accordingly, as a physical object, the B-species can be defined as a set of sister populations that are incapable to sympatry with each other. The level of B-species is very high, therefore, for forms intermediate between subspecies and B-species, an additional category is needed – a semi-species. Unlike subspecies, which differ only in size and color, a semi-species must have at least one of the following features: 1 – obvious differences in the preference for environmental conditions; 2 – a certain assortative mating with other semi-species; 3 – reduced fertility of hybrids; 4 – significant differences in morphology, physiology, behavior, etc.; 5 – the hybridization zone is relatively very narrow (parapatry). The taxonomy of birds of prey (Falconiformes, Accipitriformes) of Northern Eurasia is presented in a new (genus, B-species, semi-species, subspecies) system of categories and nomenclature.

scholarly journals Introduction. Speciation in plants and animals: pattern and process

2008 ◽  
Vol 363 (1506) ◽  
pp. 2965-2969 ◽  
Author(s):  
Richard J Abbott ◽  
Michael G Ritchie ◽  
Peter M Hollingsworth
Keyword(s):  
Evolutionary Biology ◽  
Species Concept ◽  
Natural Populations ◽  
Biological Species ◽  
Biological Species Concept ◽  
Detailed Knowledge ◽  
Hybrid Speciation ◽  
Key Points ◽  
Definition Of ◽  
Close Relatives

Although approximately 150 years have passed since the publication of On the origin of species by means of natural selection , the definition of what species are and the ways in which species originate remain contentious issues in evolutionary biology. The biological species concept, which defines species as groups of interbreeding natural populations that are reproductively isolated from other such groups, continues to draw support. However, there is a growing realization that many animal and plant species can hybridize with their close relatives and exchange genes without losing their identity. On occasion, such hybridization can lead to the origin of new species. A key to understanding what species are and the ways in which they originate rests to a large extent on a detailed knowledge of the nature and genetics of factors that limit gene flow between species and the conditions under which such isolation originates. The collection of papers in this issue addresses these topics and deals as well with some specific issues of hybrid speciation and the causes of species radiations. The papers included arise from a 1-day symposium on speciation held during the Sixth Biennial Meeting of the Systematics Association at Edinburgh in August 2007. In this introduction, we provide some background to these papers and highlight some key points made. The papers make clear that highly significant advances to our understanding of animal and plant speciation are currently being made across the range of this topic.

scholarly journals Putting the Biological Species Concept to the Test: Using Mating Networks to Delimit Species

PLoS ONE ◽  
2013 ◽  
Vol 8 (6) ◽  
pp. e68267 ◽  
Author(s):  
Lélia Lagache ◽  
Jean-Benoist Leger ◽  
Jean-Jacques Daudin ◽  
Rémy J. Petit ◽  
Corinne Vacher
Keyword(s):  
Species Concept ◽  
Biological Species ◽  
Biological Species Concept

Fern nothogenera and ×Lepinema, a new hybrid genus between Ellipinema and Lepisorus (Polypodiaceae)

Phytotaxa ◽  
2020 ◽  
Vol 455 (4) ◽  
pp. 262-266
Author(s):  
LIANG ZHANG ◽  
LI-BING ZHANG
Keyword(s):  
Species Concept ◽  
Intergeneric Hybrid ◽  
Molecular Data ◽  
Biological Species ◽  
Biological Species Concept

The biological species concept is not exclusively applicable in many groups of organisms including ferns. Interspecific fern hybrids are not rare: there are 16 intergeneric hybrid genera in ferns confirmed with molecular data. Here we add one more hybrid genus in the tribe Lepisoreae of Polypodiaceae, ×Lepinema, formed via hybridization between parents in two genera: Ellipinema and Lepisorus.

The increasing multiplicity of the species concepts

2005 ◽  
Vol 176 (2) ◽  
pp. 221-225
Author(s):  
Jean Génermont
Keyword(s):  
Species Concept ◽  
Cladistic Analysis ◽  
Biological Species ◽  
Point Of View ◽  
Biological Species Concept ◽  
Phylogenetic Species ◽  
Phylogenetic Species Concept ◽  
Ecological Criteria ◽  
Stem Species ◽  
Definition Of

Abstract In 1980, Henri Tintant advocated the usefulness of the biological species concept in paleontology. At this time, this concept was still accepted by many neontologists, but it was already rather severely criticized by some others. In fact, a lot of new concepts appeared in the course of the following two decades. While a few ones are mere adjustments of the biological concept, for instance taking in account ecological criteria, in such a way that it could be applied to clonal organisms, some others, which were developed in connexion with the cladistic theory of taxonomy, are truly new from a conceptual point of view. The diagnosable version of the phylogenetic species concept is somewhat reminiscent of Simpson’s evolutionary species concept, since it accepts phyletic speciation as well as survival of the stem species after a cladogenetic event. One of its more criticizable features, from a cladistic point of view, is that the species are not necessarilly monophyletic. On another hand, according to the monophyly version of the phylogenetic species concept, species are recognized rather subjectively as monophyletic taxa revealed by some previous cladistic analysis dealing with operational taxonomic units. A consensus on the definition of species cannot be expected, since all concepts related to the biological one are founded on population grouping on the basis of potentially identical evolutionary fates, while those which are related to cladistic taxonomy are exclusively concerned with historical features.

scholarly journals Group selection and the development of the biological species concept

2010 ◽  
Vol 365 (1547) ◽  
pp. 1853-1863 ◽  
Author(s):  
James Mallet
Keyword(s):  
Species Concept ◽  
Biological Species ◽  
Second World War ◽  
Species Level ◽  
Biological Species Concept ◽  
Ernst Mayr ◽  
World War ◽  
Mutualistic Interaction ◽  
Theodosius Dobzhansky ◽  
Second World

The development of what became known as the biological species concept began with a paper by Theodosius Dobzhansky in 1935, and was amplified by a mutualistic interaction between Dobzhansky, Alfred Emerson and Ernst Mayr after the second world war. By the 1950s and early 1960s, these authors had developed an influential concept of species as coadapted genetic complexes at equilibrium. At this time many features of species were seen as group advantages maintained by selection to avoid breakdown of beneficial coadaptation and the ‘gene pool’. Speciation thus seemed difficult. It seemed to require, more so than today, an external deus ex machina , such as allopatry or the founder effect, rather than ordinary within-species processes of natural selection, sexual selection, drift and gene flow. In the mid-1960s, the distinctions between group and individual selection were clarified. Dobzhansky and Mayr both understood the implications, but their views on species changed little. These group selectionist ideas now seem peculiar, and are becoming distinctly less popular today. Few vestiges of group selectionism and species-level adaptationism remain in recent reviews of speciation. One wonders how many of our own cherished views on evolution will seem as odd to future biologists.

scholarly journals Collembola, the biological species concept and the underestimation of global species richness

2013 ◽  
Vol 22 (21) ◽  
pp. 5382-5396 ◽  
Author(s):  
Francesco Cicconardi ◽  
Pietro P. Fanciulli ◽  
Brent C. Emerson
Keyword(s):  
Species Richness ◽  
Species Concept ◽  
Biological Species ◽  
Biological Species Concept
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