Biological Species Concept

12 Key excerpts on "Biological Species Concept"

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  Plant Biosystematics

  • William F. Grant(Author)
  • 2013(Publication Date)
  • Academic Press

    (Publisher)

  The Biological Species Concept Reexamined Bengt Jonsell Bergius Botanic Garden Stockholm University Stockholm, Sweden INTRODUCTION The titles of my lecture in the English and French versions of the program, "The Biological Species Concept Reexamined" and "Le Concept Biologique de l'Espèce: Une Revue," do not, as I understand them, express exactly the same meaning· A reexamination critical and bold enough to lead to the proposal of a new definition, or new ideas as to how the species as a category should be viewed, will not be found here, nor will this be an entirely historical review, but perhaps something in between. The subject has constantly received much attention in the last 10 or 15 years. Most commentators have, from various different starting-points, been critical of the concept; onlv a few have defended it. Among the latter is, in particular, . Grant (1981); the former include Ehlrich and Holm (1962), Bennett (1964), Ehrlich and Raven (1969), Sokal and Crovello (1970), Sokal (1973), Raven (1976, 1980), Van Valen (1976), Cronquist (1978) and Wiley (1978, 1981). The opinions of these authors will be considered in the following discussion. T am myself so far totally uncommitted on this delicate subject, and this is my only excuse for having taken on the topic. It will be clear, however, that I have considered in some depth the critical aspects of the subject and have reached at least an ad hoc view-point on the matter. The Biological Species Concept (BSC) is the most rigorously defined species concept so far proposed. However, most of its advocates have regarded it as being of very general validity for the organisms with breeding systems that are considered of particular importance in evolution and speciation. Its failure to explain the various evolutionary "dead ends" has perhaps not been taken seriously enough. The BSC may be seen as a hypothesis open to testing.

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  Mammalian Evolution, Diversity and Systematics

  • Frank Zachos, Robert Asher(Authors)
  • 2018(Publication Date)
  • De Gruyter

    (Publisher)

  all species concepts are based on biological realities. Although they may be inconsistent as practiced by some of their adherents or not applicable to all taxa, they cannot simply be wrong. The decisive question is whether the biological reality a certain species concept highlights (sterile hybrids, diagnosable differences, separate niches, etc.) is what we think deserves the label ‘species’. Below, I argue that this is ultimately a question of convention.

  Tab. 1.1: Definitions of selected species concepts dealt with in this chapter. For all of the listed concepts, more definitions than the ones given here exist, although differences are subtle and not relevant for the present discussion. Dobzhansky (1935) quoted from Wilkins (2009b). * The reference to populations in the definition of Wiley and Mayden (2000a) compared to that of Wiley (1978) was dropped to include asexual taxa. For a longer list of the 30+ published species concepts and their definitions, see chapter 4 of Zachos (2016) and Appendix B in Wilkins (2018).

  Species concept	Species definition	Reference
  Evolutionary species concept	“a lineage of ancestral descendant populations which maintains its identity from other such lineages and which has its own evolutionary tendencies and historical fate”	Wiley (1978)
  “an entity composed of organisms that maintains its identity from other such entities through time and over space and that has its own independent evolutionary fate and historical tendencies”*	Wiley and Mayden (2000a)
  Biological Species Concept	“a group of individuals fully fertile inter se, but barred from interbreeding with other similar groups by its physiological properties (producing either incompatibility of parents, or sterility of the hybrids, or both)”	Dobhzansky (1935)
  “groups of interbreeding natural populations that are reproductively isolated from other such groups. Alternatively, one can say that a biological species is a reproductively cohesive assemblage of populations”

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  Molecular Evolution and Population Genetics for Marine Biologists

  • Yuri Kartavtsev(Author)
  • 2015(Publication Date)
  • CRC Press

    (Publisher)

  To continue discussion it is necessary to de fi ne what a species is. Species De fi ni Ɵ on A species is a biological unit, which is reproductively isolated from other units, consisting of one to several more or less stable populations of sexually reproducing individuals that occupy a certain area in nature (my de fi nition). In principal points, this is the de fi nition of the BSC. In one of the original BSC de fi nitions, “ A species is a reproductive community of populations (reproductively isolated from others) that occupies a speci fi c niche in nature ” (Mayr 1982, p. 273). We will accept the BSC for further discussion, although we will keep in mind that it is restricted mainly to bisexual organisms (Mayr 1968; Timofeev-Resovsky et al. 1977; Templeton 1998). The BSC is closest to the theory of population genetics, and that is why I prefer to use this de fi nition in this and subsequent chapters; it may be restricted, but it is closer to Genetic Aspects of Speciation 95 96 Molecular Evolution and Population Genetics for Marine Biologists the theory of population genetics than other de fi nitions. Several other species concepts, with their own advances and limitations, have been critically reviewed (King 1993; Krasilov 1977). The list of these concepts is given below. • The Linnaean Species; • Biological Species Concept; • The Biological Species Concept (BSC) (Mayr 1947; 1968); • BSC Modi fi cation II (Mayr 1982); • The Recognition Species Concept (Paterson 1978; 1985); • The Cohesion Species Concept (Templeton 1998); • Evolutionary Species Concept; • Simpson’s (1961) Evolutionary Species Concept; • Wiley’s (1981) Evolutionary Species Concept; • The Ecological Species Concept (Van Valen 1976); • The Phylogenetic Species Concept (Cracraft 1983). Fig. 7.3.1. Diagram of main modes of species origin (from Bush 1975 with permission from publisher).

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  Darwin and the Nature of Species

  • David N. Stamos(Author)
  • 2012(Publication Date)
  • SUNY Press

    (Publisher)

  As Mayr (1970) points out, sterility is only one of the reproductive iso- lation mechanisms in the Biological Species Concept. According to this con- cept, a species is one or more actually or potentially interbreeding populations separated from other species by reproductive isolation mechanisms (12). These mechanisms, all of which “have a partially genetic base” (56), divide into two classes (57), namely, premating (seasonal and habitat isolation, etho- logical isolation, and mechanical isolation, an example of the latter being no sperm transfer), and postmating (gametic mortality, zygotic mortality, hy- brid inviability, and hybrid sterility). The Biological Species Concept, as Mayr further points out, is a “relational” concept, like “brother,” such that it is log- ically impossible for the world to have only one species (13–14). Mayr’s Biological Species Concept emphasizes what keeps species apart. There are a number of other species concepts, however, which emphasize what keeps a species together. Perhaps the most important of these is Hugh Paterson’s (1985) recognition species concept. Originally Paterson charac- terized a species in terms of what he called a “specific-mate recognition sys- tem,” defined as a signaling system between appropriate mating partners or their cells. Each species for Paterson had its own distinct specific-mate recognition system. However, due to the fact that many good species share a common specific-mate recognition system (as with several species of orchids from different genera), Paterson in his 1985 paper (which still 108 DARWIN AND THE NATURE OF SPECIES retained the name of his older species concept) expanded the original def- inition to something more inclusive, namely, a distinct fertilization system (which includes the specific-mate recognition system as a subclass).

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  Chemical plant Taxonomy

  • T Swain(Author)
  • 2012(Publication Date)
  • Academic Press

    (Publisher)

  B u t what merits attention is t h a t the method brought to perfection by Linnaeus, a method with roots in Aristotelean philosophy, met with reasonable success in m a n y sexual groups only because suitable variational units happened to exist in such groups. The success of the method might almost be said to have been fortuitous, were it not for the fact t h a t had early trials been unsuccessful, other systems would have been evolved. B . T H E BIOLOGICAL SPECIES Increasing understanding of the causes of the patterns of variation found in sexual groups, aided in the last few decades by a transfusion of ideas from population genetics, has led to the formulation of a theoretical basis for the so-called biological species. This concept has been developed most fully by Mayr (1940, 1942, 1948, 1949, 1955, 1957), whose writings on the topic merit attention from all biologists. Mayr's statement (1940) m a y be taken as typical of the kind of species definition to which this concept leads: Species are groups of actually or potentially inter-breeding populations which are reproductively isolated from other such groups. We owe to Mayr himself the important observation t h a t all species concepts of this kind are dualistic. They incorporate, either obviously or in some concealed manner, criteria of two different kinds, and in con-sequence are neither as simple to comprehend as they m a y at first appear, nor necessarily as useful as a guide for practice. The dualism in the above statement is obvious; on the one hand there is the criterion of reproductive isolation, and on the other the idea of collectivity, inherent in the phrase, groups of actually or potentially interbreeding populations. Reproductive isolation is, of course, the factor which determines that, in any one locality, populations of different biological species shall maintain their identity; in the genetical jargon, t h a t their gene pools shall not run together.

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  Taxonomic Guide to Infectious Diseases

  Understanding the Biologic Classes of Pathogenic Organisms

  • Jules J. Berman(Author)
  • 2019(Publication Date)
  • Academic Press

    (Publisher)

  Chapter 2

  Species and speciation

  Abstract

  Zoologists may be surprised to learn that there are many biologists, untrained in taxonomy, who believe that nature produces individual organisms and that species are simply an abstraction that we use to describe groups of individuals that happen to be similar to one another. This belief is wrong. Different individuals are not assigned to a species because they are similar to one another; they are similar to one another because they belong to the same species and have all inherited the same evolved, defining features. This chapter provides a serious discussion of “species” and explains why a species should be considered a biological entity, in its own right. We will learn why the conceptualization of “species” as an evolving gene pool can be usefully applied to the biological classification of infectious diseases. Furthermore, in this chapter we will discuss the biological process of speciation, and how it is achieved.

  Keywords

  Species; Speciation; Gene pool; Evolvability; Genetic variation; Natural selection

  Section 2.1 A species is a biological entity

  The purpose of narrative is to present us with complexity and ambiguity. Scott Turow

  It has been argued that nature produces individuals, not species; the concept of species being a mere figment of the human imagination, created for the convenience of taxonomists who need to group together similar organisms. In point of fact, there are many excellent reasons to believe that species are biological entities, on equal or better scientific footing than individual organisms. The justification for the species concept follows.

  1. 1.  Species are well defined, and membership within a species is immutable.

  Early definitions of species were fashioned to exclude most organisms, including all bacteria, all unicellular eukaryotes, and all fungi. One long-held definition for a species was that it was a class of animals that shared main characteristics and that could breed with one another. Aside from excluding the vast majority of living organisms, this early definition didn't do much to help explain how species came into existence, and did not inform us how to choose the main characteristics that determined membership in a species.

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  The Species Problem

  Ongoing Issues

  • Igor Ya. Pavlinov(Author)
  • 2013(Publication Date)
  • IntechOpen

    (Publisher)

  As the basic definition of species, I take that of Ernst Mayr [49 ]: Species are groups of interbreeding nat‐ ural populations that are reproductively isolated from other such groups. Both traits “inter‐ breeding” and “reproductively isolated” are obligatory. Many, including me, regard biological species as an ontological individual. This view was clearly formulated by Michael Ghiselin [43]. Similar to an individual organism, a species has ontogenesis: birth, infancy, adolescence, maturity, aging, and death [12 ]. This lasting exis‐ tence is carried out as a sequence of generations. This sequence is commonly known as mi‐ croevolution that may be confusing because the essence of the species ontogenesis is not an evolution. In case of success, a species’ ontogenesis culminates in stasis (i.e. cessation of evo‐ lution) that may last dozens of millions of years and more [4]. Theoretically, the potential immortality cannot be excluded. Generation of deme is a self-reproducing entity. It means that generation of deme, not the deme, is the ontological individual. So a deme is equivalent to an asexual individual organism in its role in survival and creation of the lasting entity, which is a lineage, sequential row of self-reproducing entities, sequential raw of generations of deme. Species is organization. Bonding of the intra-species components (individual organisms) is carried out by means of behavior. I suggested the term behavioral bond to designate the interaction between organisms by analogy with ionic, covalent, hydrogen, etcetera bonds [12 ]. Behavioral bonds provide cohesiveness of species. Species-specific behavior implies op‐ erating of special connections between the individuals, which transform the species into or‐ ganization with the function of survival. Primarily, these are the connections accountable for the interbreeding and reproductive isolation, which make a species a genetically closed mo‐ nad.

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  Evolution's Clinical Guidebook

  Translating Ancient Genes into Precision Medicine

  • Jules J. Berman(Author)
  • 2019(Publication Date)
  • Academic Press

    (Publisher)

  [1] .

  In point of fact, there are many excellent reasons to believe that species are biological entities on equal or better scientific footing than individual organisms. Let’s look at some of the biological properties of species.

  • –1.  Species are defined based on a fundamental biological attribute and membership within a species is immutable.

  Early definitions of species were fashioned to exclude most organisms, including all bacteria, all unicellular eukaryotes, and all fungi. One long-held definition for a species was that it was a class of animals that shared important characteristics and that the members of a species could successfully procreate with one another but not with the members of other species. This long-standing definition did not help us to understand how species come into existence and did not inform us how to choose the important characteristics that determine membership in a species.

  The modern definition of species can be expressed in three words: “evolving gene pool” [2] . This elegant definition is easy to comprehend and as we shall soon learn, serves to explain how new species come into existence [1 , 3] . Because each member of a species has a genome constructed from the species gene pool, it is clear that membership within a species is immutable (e.g., a fish cannot become a cat and a cat cannot become a goat).

  • –2.  Membership within a species is biologically determined for every living organism.

  Every organism came into existence by drawing its genome from the community gene pool and must therefore be a member of the species associated with its gene pool.

  • –3.  Species respond biologically to natural selection.

  Natural selection operates on the gene pool of a species, changing the balance of available genes. Gene variants that enhance the fitness of the species, are preserved at a high prevalence (i.e., found in a high percentage of the species population). Unfavorable genes are relegated to a low prevalence (i.e., found in a small percentage of the population). Hence, natural selection operates primarily on the gene pool; effects on individuals are secondary.

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  Available until 27 Jan |Learn more

  Species Concepts and Phylogenetic Theory

  A Debate

  • Quentin D. Wheeler, Rudolf Meier, Quentin Wheeler, Rudolf Meier(Authors)
  • 2000(Publication Date)
  • Columbia University Press

    (Publisher)

  The question thus arises: Do we expect the species problem to be resolved anytime soon? If one is to judge by the essays in this book, the answer would seem to be no. With one exception (Mayr), all the contributors to this book profess to be cladists or phylogeneticists, yet they seemingly cannot agree on how species should be perceived. The value of the essays is that they highlight many of the reasons why it has not been possible to settle on a common concept of species. Because many of the arguments involved in this debate are subtle, this introductory chapter is a guide of sorts. All discussions about species should be approached with skepticism, with a critical mind for the nuances of language, of debating ploys, and an appreciation that arguments and conclusions, while using the same words, might not mean the same thing because those words imply different things to different people and because people argue from different premises. Keeping all of this in mind will be the only way one can begin to make sense of these debates. Even then, one will probably need to grab a favorite fetish and conjure up a bit of luck. Lacking a fetish, this introductory chapter may just be the ticket.

  SPECIES CONCEPTS MATTER

  What good are definitions anyway? Why should a debate about species be taken seriously? These are questions many biologists ask out loud when they become frustrated with all the hyperbole surrounding species concepts. Many biologists, but mostly non-systematists, are quite comfortable with the concept they learned when they took introductory evolutionary biology in college and see no need to change. After all, their species concept seemingly fits what they do—population biology, behavior, genetics, or ecology. The trouble is, they often do not realize that virtually any species concept will be simpatico with what they do because what they do is generally not comparative and involves populations and/or species at a specific point in space and time. But if one is interested in comparing taxonomic entities, or wants to seek a historical interpretation of data, then species concepts matter.

  Plenty has been written about why different species concepts “impose” different interpretations on the biological world. The primary reason for being concerned about species definitions is that they frequently lead us to divide nature in very different ways. If we accept the assumption of most systematists and evolutionists that species are real things in nature, and if the sets of species specified by different concepts do not overlap, then it is reasonable to conclude that real entities of the world are being confused. It becomes a fundamental scientific issue when one cannot even count the basic units of biological diversity. After one reads the essays in this book, it should be readily apparent that the widespread use of different species concepts is a confounding influence on describing biological diversity.

  Individuating nature “correctly” is central to comparative biology and to teasing apart pattern and process, cause and effect (Cracraft 1989a). Thus, time-honored questions in evolutionary biology—from describing patterns of geographic variation and modes of speciation, to mapping character state or ecological change through time, to biogeographic analysis and the genetics of speciation, or to virtually any comparison one might make—will depend for their answer on how a biologist looks at species.

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  Logic, Methodology and Philosophy of Science VI

  • J.J. Cohen, J. Los, H. Pfeiffer, K.-P. Podewski(Authors)
  • 2011(Publication Date)
  • North Holland

    (Publisher)

  The latter share an important relationship with each other: they are able to reproduce among them-the interbreeding concept-thus maintaining the continuity of the biospecies’ gene pool, and allowing the assortment of different gene combinations in the new individuals which arise through sexual reproduction. This continual pro- duction of genetically different individual organisms, combined with natural selection, is a main factor in keeping biospecies adapted to their environ- ments, and also in maintaining their adaptability to cope with the ongoing changes of the environment, which is the biospecies’ insurance against extinction. Now, the different mechanisms of reproductive isolation, the properties of the gene pool, in particular its capacity to generate intraspecific varia- bility, and the interbreeding property, are all emergent properties of biospecies as integrated individual systems. This qualification comes from the fact that even when the mechanisms and properties are rooted in the REALITY OF BIOLOGICAL SPECIES 493 component individual organisms of each biospecies, they are not charac- teristic of them as individual components, but they become apparent only as a result of their interrelationships. Thus an individual organism is not endowed by itself with reproductive isolation towards an individual be- longing to another biospecies : the property of being isolated only exists as a consequence of a complex of evolutionary forces which acted on its biospecies, and only makes sense in the framework of its relationships with other individuals. In the same way, and individual organism may be well adapted to its environment, but the continuity of the biospecies to which it belong’s ability of being adapted is not dependent on it as an individual, but on the total amount of the genetic characteristics of its biospecies. Within this biospecies, it merely represents a very limited fragment, and a temporal one of the biospecies’ overall genetic potentiality.

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  The Species Problem

  A Conceptual History

  • Igor Ya. Pavlinov(Author)
  • 2023(Publication Date)
  • CRC Press

    (Publisher)

  Collier 1985 : 17].

  4 An “elephant” of a well-known ancient Indian parable about blind men, who touch its different parts and imagine it differently, which is mentioned sometimes with respect to the species problem [Brooks and McLennan 1999 ; Winston 1999 ], may be taken as a vague illustration of such boundary object.

  It is evident from the preceding that this “conceptualistic” question makes any sense only if it is set and answered with respect to a certain substantive theory. Regarded in its quite general biologically meaningful sense, it could be addressed as a theory that treats biota as a self-developing nonequilibrium system; it will be discussed in more detail elsewhere (see Section 6.1 ). In a more particular sense, it presumes that these are certain particular conceptions that are subject to evaluation, and as far as they function differently in different substantive theories, the particular criteria for their evaluation should also be different [Richards 2010 ]. Accordingly, there will be at least as many contextually specified questions about the significance of species conception and possible answers to them as there are such theories. For instance, one of them is such taxonomic theory, in which species category is fundamental [Blackwelder 1967 ; Mayr 1969 , 1988 ; Stuessy 2008 ]. Another is evolutionary theory, in which species is considered a final stage of the speciation process [Hull 1977 ; Mayr 1982 , 1988 ; Ghiselin 1997 ; Shaw 2012 ]. The third is synecological theory, in which species figures as an element of community structure, occupying a certain ecological niche in it [Odum 1953 ; Schwartz 1980 ; Chase and Leibold 2003 ]. Besides, a specific context for evaluating species conceptions is set by the pragmatics of biodiversity protection issues [Sarkar 2005 ; Barraclough 2019

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  The Philosophy of Nicolai Hartmann

  • Roberto Poli, Carlo Scognamiglio, Frederic Tremblay, Roberto Poli, Carlo Scognamiglio, Frederic Tremblay(Authors)
  • 2011(Publication Date)
  • De Gruyter

    (Publisher)

  Chapter 6: Nicolai Hartmann’s Definition of Biological Species Frederic Tremblay 6.1 Introduction Before the Darwinian revolution, species were thought to be universals. Since then, numerous attempts have been made to propose new defini-tions. A widely held view is that species are individuals. Another is that they are populations or groups of populations. Others have proposed that species are lineages or temporal relations between speciation events. Others, including Darwin, have even suggested that the term ‘species’ is arbitrary and that we might have to give it up altogether. These are only a few examples. Nicolai Hartmann has defined ‘species’ as a unitary sys-tem of processes or a process of life of a higher-order. To give a clear understanding of Hartmann’s conception, I present his method of def-inition, his concept of “organism,” and his correlated concept of “spe-cies.” I end the paper by pointing out two possible systematic inconsis-tencies. Hartmann was already well acquainted with biology through the medical education he received prior to beginning his studies in philos-ophy. He elaborates his philosophy of biology in Philosophische Grundfra-gen der Biologie (1912a) and Philosophie der Natur (1950). Philosophische Grundfragen der Biologie belongs to the writings of the early period of his career, which do not represent Hartmann’s mature thought. In Phi-losophie der Natur he recuperates topics from the earlier treatise and im-proves their treatment by integrating them into a systematic framework. Since the section of Philosophie der Natur devoted to the organological categories represents Hartmann’s mature philosophy of biology (thir-ty-eight years have passed since the first text), I set aside the text of the early period to focus on Philosophie der Natur.

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