I spell out and update the individuality thesis, that species are individuals, and not classes, sets, or kinds. I offer three complementary presentations of this thesis. First, as a way of resolving an inconsistent triad about natural kinds; second, as a phylogenetic systematics theoretical perspective; and, finally, as a novel recursive account of an evolved character. These approaches do different sorts of work, serving different interests. Presenting them together produces a taxonomy of the debates over the thesis, and isolates ways (...) it has been productive. This goes to the larger point of this paper: a defense of the individuality thesis in terms of its utility, and an update of it in light of recent theoretical developments and empirical work in biology. (shrink)

This paper aims to offer a new argument in defence bacterial species pluralism. To do so, I shall first present the particular issues derived from the conflict between the non-theoretical understanding of species as units of classification and the theoretical comprehension of them as units of evolution. Secondly, I shall justify the necessity of the concept of species for the bacterial world, and show how medicine and endosymbiotic evolutionary theory make use of different concepts of bacterial species due to their (...) distinctive purposes. Finally, I shall show how my argument provides a new source of defence for bacterial pluralism. (shrink)

For more than fifty years, taxonomists have proposed numerous alternative definitions of species while they searched for a unique, comprehensive, and persuasive definition. This monograph shows that these efforts have been unnecessary, and indeed have provably been a pursuit of a will o’ the wisp because they have failed to recognize the theoretical impossibility of what they seek to accomplish. A clear and rigorous understanding of the logic underlying species definition leads both to a recognition of the inescapable ambiguity that (...) affects the definition of species, and to a framework-relative approach to species definition that is logically compelling, i.e., cannot not be accepted without inconsistency. An appendix reflects upon the conclusions reached, applying them in an intellectually whimsical taxonomic thought experiment that conjectures the possibility of an emerging new human species. (shrink)

The nature of science is a primary goal in school science. Most teachers are not well-prepared for teaching NOS, but a sophisticated and in-depth understanding of NOS is necessary for effective teaching. Some authors emphasize the need for teaching NOS in context. Species, a central concept in biology, is proposed in this article as a concrete example of a means for achieving increased understanding of NOS. Although species are commonly presented in textbooks as fixed entities with a single definition, the (...) concept of species is a highly discussed one in the science and the philosophy of biology. A multitude of species concepts exist, reflecting both the views and interests of researchers and their utility in different organism groups. The present study serves to address the following questions: How do textbooks in Norwegian primary and lower secondary schools present the concept of species? Can inquiries into the concept of “species” serve to highlight aspects of NOS? A review of the available literature on species and species concepts in school is also performed. In the schoolbooks, the biological species concept is commonly used as the main definition, whereas the morphological species concept is represented by additional remarks of similarity. The potential and pitfalls of using the species concept for teaching NOS are discussed, with NOS being discussed both as a family resemblance concept and as a consensus list. Teacher education is proposed as a starting point for inducing a more sophisticated view of biology into schools. (shrink)

Biological science uses multiple species concepts. Order can be brought to this diversity if we recognize two key features. First, any given species concept is likely to have a patchwork structure, generated by repeated application of the concept to new domains. We illustrate this by showing how two species concepts (biological and ecological) have been modified from their initial eukaryotic applications to apply to prokaryotes. Second, both within and between patches, distinct species concepts may interact and hybridize. We thus defend (...) a semantic picture of the species concept as a collection of interacting patchwork structures. Thus, although not all uses of the term pick out the same kind of unit in nature, the diversity of uses reflects something more than mere polysemy. We suggest that the emphasis on the use of species to pick out natural units is itself problematic, because that is not the term’s sole function. In particular, species concepts are used to manage inquiry into processes of speciation, even when these processes do not produce clearly delimited species. (shrink)

Species are considered the basic unit of biological classification and evolution. Hence, they are used as a benchmark in several fields, although the ontological status of such a category has always been a matter of debate. This paper aims to discuss the problem of the definition of species within the new mechanistic approach. Nevertheless, the boundary between entities, activities, and mechanisms remains difficult to establish and always requires an analysis of what is meant by explanation. As a case study, the (...) paper describes the debate concerning the species category by considering different kingdoms: Animals, Bacteria, and Fungi. The inherently biological differences between those groups prevent the use of a single, universally applicable concept of species that could fit the mechanisms responsible for the variability present in these kingdoms. The same issue is encountered within each group, as highlighted through a focus on mammals and microbes. This controversy has given rise to opposite approaches, namely: monism, which looks for a single definition that might account for all species, and pluralism, which admits that different groups of organisms require somewhat different definitions. In order to develop an adequate definition of species, we propose to apply a new mechanistic framework, which considers the ontic-epistemic dimensions of scientific explanation in close parallel. The apt correlation between epistemic and the ontic aspects highlights the way in which the concept of species and the reference to data are strictly co-determined. This suggests that the concept of species is better understandable within a dual ontic-epistemic approach. (shrink)

The Darwinian theory of evolution is itself evolving and this book presents the details of the core of modern Darwinism and its latest developmental directions. The authors present current scientific work addressing theoretical problems and challenges in four sections, beginning with the concepts of evolution theory, its processes of variation, heredity, selection, adaptation and function, and its patterns of character, species, descent and life. The second part of this book scrutinizes Darwinism in the philosophy of science and its usefulness in (...) understanding ecosystems, whilst the third section deals with its application in disciplines beyond the biological sciences, including evolutionary psychology and evolutionary economics, Darwinian morality and phylolinguistics. The final section addresses anti-Darwinism, the creationist view and issues around teaching evolution in secondary schools. The reader learns how current experimental biology is opening important perspectives on the sources of variation, and thus of the very power of natural selection. This work examines numerous examples of the extension of the principle of natural selection and provides the opportunity to critically reflect on a rich theory, on the methodological rigour that presides in its extensions and exportations, and on the necessity to measure its advantages and also its limits. Scholars interested in modern Darwinism and scientific research, its concepts, research programs and controversies will find this book an excellent read, and those considering how Darwinism might evolve, how it can apply to the human sciences and other disciplines beyond its origins will find it particularly valuable. Originally produced in French (Les Mondes Darwiniens), the scope and usefulness of the book have led to the production of this English text, to reach a wider audience. This book is a milestone in the impressive penetration by Francophone scholars into the world of Darwinian science, its historiography and philosophy over the last two decades. Alex Rosenberg, R. Taylor Cole Professor of Philosophy, Duke University Until now this useful and comprehensive handbook has only been available to francophones. Thanks to this invaluable new translation, this collection of insightful and original essays can reach the global audience it deserves. Tim Lewens, University of Cambridge. (shrink)

The dichotomy between ‘typological thinking’ and ‘population thinking’ features in a range of debates in contemporary and historical biology. The origins of this dichotomy are often traced to Ernst Mayr, who is said to have coined it in the 1950s as a rhetorical device that could be used to shield the Modern Synthesis from attacks by the opponents of population biology. In this two-part essay, I argue that the origins of the typology/population dichotomy are considerably more complicated and more interesting (...) than is commonly thought. In the first part, I argued that Mayr's dichotomy was based on two distinct type/population contrasts that had been articulated much earlier by George Gaylord Simpson and Theodosius Dobzhansky. Their distinctions made eminent sense in their own, isolated contexts. In this second part, I will show how Mayr conflated these type/population distinctions and blended in some of his own, unrelated concerns with ‘types’ of a rather different sort. Although Mayr told his early critics that he was merely making “a temporary oversimplification,” he ended up burdening the history and philosophy of biology with a troubled dichotomy. (shrink)

The concept of species is one of the core concepts in biology and one of the cornerstones of evolutionary biology, yet it is rife with conceptual problems. Philosophers of biology have been discussing the concept of species for decades, and in doing so they sometimes appeal to the views of biologists. However, their statements as to what biologists think are seldom supported by empirical data. In order to investigate what biologists actually think about the key issues related to the problem (...) of species, we have conducted a survey on the sample of 193 biologists from the population of biologists from over 150 biology departments at universities in the US and the EU. This article presents and discusses the results of the survey. Some results confirm and others falsify the reiterated statements of philosophers of biology as to what biologists think, but all results we obtained should be informative and relevant for future discussions of the problem of species. (shrink)

Historians and philosophers of science agree that Darwin had an understanding of species which led to a workable theory of their origins. To Darwin species did not differ essentially from ‘varieties’ within species, but were distinguishable in that they had developed gaps in formerly continuous morphological variation. Similar ideas can be defended today after updating them with modern population genetics. Why then, in the 1930s and 1940s, did Dobzhansky, Mayr and others argue that Darwin failed to understand species and speciation? (...) Mayr and Dobzhansky argued that reproductively isolated species were more distinct and ‘real’ than Darwin had proposed. Believing species to be inherently cohesive, Mayr inferred that speciation normally required geographic isolation, an argument that he believed, incorrectly, Darwin had failed to appreciate. Also, before the sociobiology revolution of the 1960s and 1970s, biologists often argued that traits beneficial to whole populations would spread. Reproductive isolation was thus seen as an adaptive trait to prevent disintegration of species. Finally, molecular genetic markers did not exist, and so a presumed biological function of species, reproductive isolation, seemed to delimit cryptic species better than character-based criteria like Darwin’s. Today, abundant genetic markers are available and widely used to delimit species, for example using assignment tests: genetics has replaced a Darwinian reliance on morphology for detecting gaps between species. In the 150th anniversary of The Origin of Species , we appear to be returning to more Darwinian views on species, and to a fuller appreciation of what Darwin meant. (shrink)

-/- Because species names play an important role in scientific communication, it is more important that species be understood to be taxa than that they be equated with functional ecological or evolutionary entities. Although most biologists would agree that taxa are composed of organisms that share a unique common history, 2 major challenges remain in developing a species-as-taxa concept. First, grouping: in the face of genealogical discordance at all levels in the taxonomic hierarchy, how can we understand the nature of (...) taxa? Second, ranking: what criteria should be used to designate certain taxa in a nested series as being species? The grouping problem can be solved by viewing taxa as exclusive groups of organisms— sets of organisms that form a clade for a plurality of the genome (more than any conflicting set). However, no single objective criterion of species rank can be proposed. Instead, the species rank should be assigned by practitioners based on the semisubjective application of a set of species-ranking criteria. Although these criteria can be designed to yield species taxa that approximately match the ecological, evolutionary, and morphological entities that taxonomists have traditionally associated with the species rank, such a correspondence cannot be enforced without undermining the assumption that species are taxa. The challenge and art of monography is to use genealogical and other kinds of data to assign all organisms to one and only one species-ranked taxon. Various implications of the species-as-ranked-taxa view are discussed, including the synchronic nature of taxa, fossil species, the treatment of hybrids, and species nomenclature. I conclude that, although challenges remain, adopting the view that species are ranked taxa will facilitate a much-needed revolution in taxonomy that will allow it to better serve the biodiversity informatic needs of the 21st century. (shrink)

The dichotomy between ‘typological thinking’ and ‘population thinking’ features in a range of debates in contemporary and historical biology. The origins of this dichotomy are often traced to Ernst Mayr, who is said to have coined it in the 1950s as a rhetorical device that could be used to shield the Modern Synthesis from attacks by the opponents of population biology. In this two-part essay I argue that the origins of the typology/population dichotomy are considerably more complicated and more interesting (...) than is commonly thought. In this first part, I will argue that Mayr's dichotomy was based on two distinct type/population contrasts that had been articulated much earlier by George Gaylord Simpson and Theodosius Dobzhansky. Their distinctions made eminent sense in their own, isolated contexts. In the second part, I will show how Mayr conflated these type/population distinctions and blended in some of his own, unrelated concerns with ‘types’ of a rather different sort. Although Mayr told his early critics that he was merely making “a temporary oversimplification,” he ended up burdening the history and philosophy of biology with a troubled dichotomy. (shrink)