What is a species? Essences and generation

Arguments against essentialism in biology rely strongly on a claim that modern biology abandoned Aristotle’s notion of a species as a class of necessary and sufficient properties. However, neither his theory of essentialism, nor his logical definition of species and genus (eidos and genos) play much of a role in biological research and taxonomy, including his own. The objections to natural kinds thinking by early twentieth century biologists wrestling with the new genetics overlooked the fact that species have typical developmental cycles and most have a large shared genetic component. These are the “what-it-is-to-be” members of that species. An intrinsic biological essentialism does not commit us to Aristotelian notions, nor even modern notions, of essence. There is a long-standing definition of “species” and its precursor notions that goes back to the Greeks, and which Darwin and pretty well all biologists since him share, that I call the Generative Conception of Species. It relies on there being a shared generative power that makes progeny resemble parents. The “what-it-is-to-be” a member of that species is that developmental type, mistakes in development notwithstanding. Moreover, such “essences” have always been understood to include deviations from the type. Finally, I shall examine some implications of the collapse of the narrative about essences in biology.     

At the Margins of Moral Personhood

In this article I examine the proposition that severe cognitive disability is an impediment to moral personhood. Moral personhood, as I understand it here, is articulated in the work of Jeff McMahan as that which confers a special moral status on a person. I rehearse the metaphysical arguments about the nature of personhood that ground McMahan’s claims regarding the moral status of the “congenitally severely mentally retarded” (CSMR for short). These claims, I argue, rest on the view that only intrinsic psychological capacities are relevant to moral personhood: that is, that relational properties are generally not relevant. In addition, McMahan depends on an argument that species membership is irrelevant for moral consideration and a contention that privileging species membership is equivalent to a virulent nationalism (these will be discussed below). In consequence, the CSMR are excluded from moral personhood and their deaths are less significant as their killing is less wrong than that of persons. To throw doubt on McMahan’s conclusions about the moral status and wrongness of killing the CSMR I question the exclusive use of intrinsic properties in the metaphysics of personhood, the dismissal of the moral importance of species membership, and the example of virulent nationalism as an apt analogy. I also have a lot to say about McMahan’s empirical assumptions about the CSMR.     

Individual essentialism in biology

A few philosophers of biology have recently explicitly rejected Essential Membership, the doctrine that if an individual organism belongs to a taxon, particularly a species, it does so essentially. But philosophers of biology have not addressed the broader issue, much discussed by metaphysicians on the basis of modal intuitions, of what is essential to the organism. In this paper, I address that issue from a biological basis, arguing for the Kripkean view that an organism has a partly intrinsic, partly historical, essence. The arguments appeal to the demands of biological explanation and are analogous to arguments that I have given elsewhere that a taxon has a partly intrinsic, partly historical, essence. These conclusions about the essences of individuals and taxa yield an argument for Essential Membership. Finally, I cast doubt on LaPorte’s objection to that doctrine arising from the view that a species cannot survive having a daughter.     

A case for resurrecting lost species—review essay of Beth Shapiro’s, “How to Clone a Mammoth: The Science of De-extinction”

The title of Beth Shapiro’s ‘How to Clone a Mammoth’ contains an implicature: it suggests that it is indeed possible to clone a mammoth, to bring extinct species back from the dead. But in fact Shapiro both denies this is possible, and denies there would be good reason to do it even if it were possible. The de-extinct ‘mammoths’ she speaks of are merely ecological proxies for mammoths—elephants re-engineered for cold-tolerance by the addition to their genomes of a few mammoth genes. Shapiro’s denial that genuine species de-extinction is possible is based on her assumption that resurrected organisms would need to be perfectly indistinguishable from the creatures that died out. In this article I use the example of an extinct New Zealand wattlebird, the huia, to argue—contra Shapiro—that there are compelling reasons to resurrect certain species if it can be done. I then argue—again, contra Shapiro—that synthetically created organisms needn’t be perfectly indistinguishable from their genetic forebears in order for species de-extinction to be successful.     

Statistical neuroscience in the single trial limit

Individual neurons often produce highly variable responses over nominally identical trials, reflecting a mixture of intrinsic ‘noise’ and systematic changes in the animal’s cognitive and behavioral state. Disentangling these sources of variability is of great scientific interest in its own right, but it is also increasingly inescapable as neuroscientists aspire to study more complex and naturalistic animal behaviors. In these settings, behavioral actions never repeat themselves exactly and may rarely do so even approximately. Thus, new statistical methods that extract reliable features of neural activity using few, if any, repeated trials are needed. Accurate statistical modeling in this severely trial-limited regime is challenging, but still possible if simplifying structure in neural data can be exploited. We review recent works that have identified different forms of simplifying structure — including shared gain modulations across neural subpopulations, temporal smoothness in neural firing rates, and correlations in responses across behavioral conditions — and exploited them to reveal novel insights into the trial-by-trial operation of neural circuits.     

Adaptation,fitness and the selection-optimality links

We critically examine a number of aspects of Grafen’s ‘formal Darwinism’ project. We argue that Grafen’s ‘selection-optimality’ links do not quite succeed in vindicating the working assumption made by behavioural ecologists and others—that selection will lead organisms to exhibit adaptive behaviour—since these links hold true even in the presence of strong genetic and developmental constraints. However we suggest that the selection-optimality links can profitably be viewed as constituting an axiomatic theory of fitness. Finally, we compare Grafen’s project with Fisher’s ‘fundamental theorem of natural selection’, and we speculate about whether Grafen’s results can be extended to a game-theoretic setting.     

On justifying arguments of species membership

In the debate about the moral status of human beings at the margins of life, arguments of species membership are often considered to be the least plausible ones. Against this backdrop, this article explores two possible ways to formulate feasible arguments of species membership. The first is an (in the broadest sense of the word) Aristotelian or neo-Aristotelian argument; the second is an argument from the intrinsic logic of human rights, which Robert Spaemann refers toas a ‘transcendental-pragmatic’ argument. On these grounds, the article proposes a philosophical justification for an at least moderate speciesism.     

How Sex Selection Undermines Reproductive Autonomy

Non-medical sex selection is premised on the notion that the sexes are not interchangeable. Studies of individuals who undergo sex selection for non-medical reasons, or who have a preference for a son or daughter, show that they assume their child will conform to the stereotypical roles and norms associated with their sex. However, the evidence currently available has not succeeded in showing that the gender traits and inclinations sought are caused by a “male brain” or a “female brain”. Therefore, as far as we know, there is no biological reason why parents cannot have the kind of parenting experience they seek with a child of any sex. Yet gender essentialism, a set of unfounded assumptions about the sexes which pervade society and underpin sexism, prevents parents from realising this freedom. In other words, unfounded assumptions about gender constrain not only a child’s autonomy, but also the parent’s. To date, reproductive autonomy in relation to sex selection has predominantly been regarded merely as the freedom to choose the sex of one’s child. This paper points to at least two interpretations of reproductive autonomy and argues that sex selection, by being premised on gender essentialism and/or the social pressure on parents to ensure their children conform to gender norms, undermines reproductive autonomy on both accounts.     

Fuzzy Logic Modeling of Contamination Degree of Ni and V Metal Species in Sediments from the Crude Oil Prospecting Area of the Ondo Coast,Nigeria

There are numerous statistical models for evaluating the degree of pollution in an environment. This study presents a fuzzy logic–based model—simple fuzzy classification (SFC)—for evaluating contamination of Ni and V species in the sediments of Nigeria's Ondo coastal area. Concentrations of five species of these metals were obtained from 10 sampling sites following sequential extractions from sediments. The results were formulated into a fuzzy membership function matrix based on three classifications relative to regulatory standards and sediments’ degree of contamination. The results of the SFC show that the estuary is moderately enriched by Ni species in a range of 61–84% and further introduction of Ni may shift its contamination level into the highly polluted category. The SFC results also show that the estuary is clean of V species contamination in a range of 77–99%. The Ni and V were associated with the organic specie notably at the crude oil exploration site and at the coastal discharge point. Crude oil exploration and domestic wastes discharges are notable sources of metal contaminations into the estuary. However, the salinity incursion from the coastal ocean and prevailing biogeochemistry affect the species in which the metals exist.     

Applying complementary species vulnerability assessments to improve conservation strategies in the Galapagos Marine Reserve

Marine biodiversity can be protected by identifying vulnerable species and creating marine protected areas (MPAs) to ensure their survival. A wide variety of methods are employed by environmental managers to determine areas of conservation priority, however which methods should be applied is often a subject of debate for practitioners and scientists. We applied two species vulnerability assessments, the International Union for the Conservation of Nature (IUCN) red list of threatened species and FishBase’s intrinsic vulnerability assessment, to fish communities in three coastal habitats (mangrove, rocky and coral) on the island of San Cristobal, Galapagos. When using the IUCN red list of threatened species, rocky reefs hosted the greatest number of vulnerable species, however when applying the FishBase assessment of intrinsic vulnerability mangroves hosted the greatest abundance of ‘very-highly’ vulnerable species and coral ecosystems hosted the greatest abundance of ‘highly’ vulnerable species. The two methods showed little overlap in determining habitat types that host vulnerable species because they rely on different biological and ecological parameters. Since extensive data is required for IUCN red list assessments, we show that the intrinsic vulnerability assessment from FishBase can be used to complement the IUCN red list especially in data-poor areas. Intrinsic vulnerability assessments are based on less data-intensive methods than the IUCN red list, but nonetheless may bridge information gaps that can arise when using the IUCN red list alone. Vulnerability assessments based on intrinsic factors are not widely applied in marine spatial planning, but their inclusion as a tool for forming conservation strategies can be useful in preventing species loss.     

Threads that Guide or Ties that Bind: William Kirby and the Essentialism Story

Nineteenth-century British entomologist William Kirby is best known for his generic division of bees based on tongues and his vigorous defence of natural theology. Focusing on these aspects of Kirby’s work has lead many current scholars to characterise Kirby as an “essentialist.” As a result of this characterisation, many important aspects of his work, Monographia Apum Angliæ (1802) have been over-looked or misunderstood. Kirby’s religious devotion, for example, have lead some scholars to assume Kirby used the term “type” for connecting an ontological assumption about essences with a creationist assumption about species fixity, which I argue conceals a variety of ways Kirby employed the term. Also, Kirby frequently cautioned against organising a classification system exclusively by what he called “analytic reasoning,” a style of reasoning 20th century scholars often associate with Aristotelian logic of division. I argue that Kirby’s critique of analytic reasoning brought the virtues of his own methodological agenda into sharp relief. Kirby used familiar metaphors in the natural history literature – Ariadne’s thread, the Eleusinian mysteries, and Bacon’s bee and spider metaphors – to emphasise the virtues of building tradition and cooperation in the goals and methodological practices of 19th century British naturalists.     

The Relationship between Cultural Anxiety and Ethnic Essentialism: The Mediating Role of an Endorsement of Multicultural Ideology

Many studies have explored the social consequences of ethnic essentialism in recent decades. In addition, a few studies have focused on the impact of perceived cultural context on ethnic essentialism. However, it is not clear why perceived cultural context can lead to changes in ethnic essentialism. In the present study, we hypothesized that the cultural anxiety of ethnic minorities may trigger a strong endorsement of and support for a multicultural ideology, thereby affecting beliefs about ethnic groups. To address the issue, 226 Tibetan and 102 Hui college students from Mainland China completed our questionnaires. The results across the two samples showed that (1) cultural anxiety was positively associated with both the endorsement of a multicultural ideology and ethnic essentialism, (2) cultural anxiety and the endorsement of a multicultural ideology positively predicted ethnic essentialism after controlling for demographic variables, and (3) cultural anxiety had both a direct effect on ethnic essentialism and an indirect effect on ethnic essentialism through the endorsement of a multicultural ideology. Our findings suggest that when ethnic minorities experience cultural anxiety, they might endorse a multicultural ideology and adopt essentialism to affirm their ethnic identities.     

希木龙念珠菌研究进展

希木龙念珠菌Candida haemulonii是一种与耳念珠菌亲缘关系十分相近的物种。近年来,由其引发的侵袭性真菌疾病的发病率不断升高。作为一种多重耐药真菌,希木龙念珠菌对常见抗真菌药物的耐药性甚至超过耳念珠菌。体外药敏试验证实大部分希木龙念珠菌菌株对唑类、多烯类以及棘白菌素类等抗真菌药物耐药,尤其是对两性霉素B具有天然抗性。不仅如此,临床传统的生化方法难以对该菌准确鉴定,常用的商品化鉴定产品往往将其错误鉴定为毕赤酵母或者新型隐球菌。为了进一步加深对希木龙念珠菌的认识,本文结合国内外的流行病学数据与研究进展,从感染现状、生物学特征、耐药性进行综述,同时总结该菌目前诊断、治疗和预防措施。     

Umwelt Transitions: Uexküll and Environmental Change

What role does environmental change play in Jakob von Uexküll’s thought? And what role can it play in a up-to-date Uexküllian framework? Admittedly, in hindsight it appears that the Umwelt theory suffers from its reliance on Uexküll’s false premise that the environment (including its mixture of species) is generally stable. In this article, the Umwelt theory of Uexküll is reviewed in light of modern findings related to environmental change, especially from macroevolution. Uexküll’s thought is interpreted as a distinctive theory of phenomenology—an ‘Uexküllian phenomenology’—characterized by an assumption of the (in the realm of life) universal existence of a genuine first person perspective, i.e., of experienced worlds. It is suggested that acknowledging this distinctiveness is critical for eco-phenomenology as well as for biosemiotics; the latter of which can only thus thrive as a true ‘semiotics of being’, rather than a mere ‘semiotics of functioning’.     

Species’ roles in food webs show fidelity across a highly variable oak forest

Ecological communities are composed of many species and an intricate network of interactions between them. Because of their overall complexity, an intriguing approach to understanding network structure is by breaking it down into the structural roles of its constituent species. The structural role of a species can be directly measured based on how it appears in network motifs – the basic building blocks of complex networks. Here, we study the distribution of species’ roles at three distinct spatio‐temporal scales (i.e. species, network, and temporal) in host–parasitoid networks collected across 22 sites over two years within a fragmented landscape of oaks in southern Finland. We found that species’ roles for hosts and parasitoids were heterogeneously distributed across the study system but that roles are strongly conserved over spatial scales. In addition, we found that species’ roles were remarkably consistent between years even in the presence of disturbances (e.g. species turnover). Overall, our results suggest that species’ roles are an intrinsic property of species that may be predictable over spatial and temporal scales.     

Differentiation between native and exotic plant species from a dry grassland: fundamental responses to resource availability,and growth rates

Abstract Species from a mixed native/exotic dry grassland community in New Zealand were experimentally assessed for three ecophysiological parameters: nutrient response, water response and maximum relative growth rate (RGR_max). These are parameters that relate to factors proposed as important in structuring plant communities in dry environments. Native and exotic species did not differ consistently in water response. Exotic species tended to have a greater response to nutrients, but there was considerable overlap between native and exotic guilds. However, exotic species did have a higher intrinsic growth rate, and this effect was not attributable to differences in life histories. The results suggest that the exotic species are more competitive and more generalist than the native species. These traits are compatible with the concept of the ‘ideal invader’, and suggest the C‐R strategy of Grime’s theory. The native species showed characteristics consistent with stress tolerance (sensu Grime). The paucity of evidence for ecophysiological differentiation between the native and exotic guilds, except in intrinsic growth rate, indicates that the exotic species were able to invade not because they had superior adaptation to the physical environment, but because they possessed, by pre‐adaptation, the same ways of coping with that environment as the existing species. However, their ability to invade can be related to their growth rates.     

The first range-wide assessment of Saddle-billed Stork Ephippiorhynchus senegalensis distribution

The Saddle-billed Stork Ephippiorhynchus senegalensis exemplifies a case in conservation research in which a species is assessed as Least Concern on the IUCN Red List and the resulting consideration of low conservation priority has precluded proper scientific study. As a first step in understanding this stork’s true status, we collated all available data to develop a distribution map and then investigated range-wide patterns of occurrence. The updated map greatly improves on past knowledge of the stork’s distribution and helps to identify regions where range contractions have occurred, particularly in Central Africa and parts of West Africa. We found that the stork’s distribution closely overlaps with protected areas and that there has been an overall increase in surface water (largely manmade water bodies)—a proxy for habitat—across the species’ extent of occurrence in recent decades. While this research represents a valuable contribution to our understanding of the Saddle-billed Stork, it also highlights the need for unbiased empirical data, especially from areas that are poorly surveyed, for developing a science-based conservation status assessment.     

Natural selection as an emergent process: instructional implications

Student reasoning about cases of natural selection is often plagued by errors that stem from miscategorising selection as a direct, causal process, misunderstanding the role of randomness, and from the intuitive ideas of intentionality, teleology and essentialism. The common thread throughout many of these reasoning errors is a failure to apply ‘population thinking’. Students fail to recognise that natural selection refers to changes in the distribution of certain traits at the population level, the collective, resulting from interactions between individual organisms and their environment at the next lower level in the system. Processes like selection are emergent processes in hierarchical systems, where patterns in a collective are generated by interactions at the lower level. By helping students develop an emergent process schema that enables them to recognise that even random interactions at one level in a system can generate predictable patterns at a higher level, their understanding of natural selection should improve. Some studies have shown this to be an effective approach for teaching other emergent processes. Instructional recommendations based on these studies are presented here, but more research is needed to determine the full extent to which this approach can improve students’ understanding.     

Intrinsic guild structure: determination from competition experiments

A new approach is introduced for determining the intrinsic guild classification of a group of species. Previous delimitations of intrinsic guilds have used evidence of spatial distributions (i.e. species co-occurrences), but this is rather indirect evidence. The new method is based on the results of species pairwise competition experiments, and thus uses direct data on species interactions. As with the spatial-distribution intrinsic guild approach, no prior assumptions are made about the classification, nor about which characters are related to guild membership.
The method is applied to the results of two published experiments. For one, little independent evidence is available to judge the classification. There is no correlation between the guild classification obtained and gross morphology, but there is no reason to expect any such correlation. For the second experiment, intrinsic guild classifications had previously been obtained from distributional data, and the experimentally-based intrinsic classifications was identical to a distributionally-based one.
We suggest that combining evidence from field distributions with experimental evidence offers a rigorous way to determine the true guild structure of communities, offering convincing conclusions when the two lines of evidence converge.     

By genes alone: a model selectionist argument for genetical explanations of cooperation in non-human organisms

I distinguish two versions of kin selection theory—a purely genetic version (GKST) and a version that also appeals to cultural (i.e. non-genetically-derived) forms of cooperation (WKST)—and present an argument in favor of using the former when it comes to accounting for the evolution of cooperation in non-human organisms. Specifically, I first show that both GKST and WKST are equally mathematically coherent—they can both be derived from the Price equation—but not necessarily equally empirically plausible, as they are based on different assumptions about the inheritance system underlying the cooperative phenotype. Given this, I then, second, present a model selection theoretic argument in favor of GKST over WKST. This argument is based on the fact that, in non-human cases, the former theory is likely to be as empirically successful as WKST, while containing fewer degrees of freedom. I end by defending both the intrinsic importance of this argument and its relevance to the discussion surrounding the “gene’s eye view of evolution.”