Animal evolution. The end of the intermediate taxa?

Contrary to general belief, there has not been a reliable, global phylogeny of animals at hand within the past few decades. Recent progress in molecular phylogeny is rapidly changing the situation and has provided trees that constitute a reference frame for discussing the still controversial evolution of body plans. These trees, once purged of their possible artefacts, have already yielded confirmation of traditional, anatomically based, phylogenies as well as several new and quite significant results. Of these, one of the most striking is the disappearance of two superphyla (acoelomates such as flatworms, pseudocoelomates such as nematodes) previously thought to represent grades of intermediate complexity between diploblasts (organisms with two germ layers) and triploblasts (organisms with three germ layers). The overall image now emerging is of a fairly simple global tree of metazoans, comprising only a small number of major branches. The topology nicely accounts for the striking conservation of developmental genes in all bilaterians and suggests a new interpretation of the 'Cambrian explosion' of animal diversity.     

Why the club of earth?

Recently, a small group of ecologists and evolutionary biologists anointed themselves The Club of Earth and made a public pronouncement on the importance of preserving biological diversity. For me, the most frequent result of being a member has been a series of queries about why the group had been formed.     

Does the Order of Invasive Species Removal Matter? The Case of the Eagle and the Pig

Background

Invasive species are recognized as a primary driver of native species endangerment and their removal is often a key component of a conservation strategy. Removing invasive species is not always a straightforward task, however, especially when they interact with other species in complex ways to negatively influence native species. Because unintended consequences may arise if all invasive species cannot be removed simultaneously, the order of their removal is of paramount importance to ecological restoration. In the mid-1990s, three subspecies of the island fox Urocyon littoralis were driven to near extinction on the northern California Channel Islands owing to heightened predation by golden eagles Aquila chrysaetos. Eagles were lured to the islands by an abundant supply of feral pigs Sus scrofa and through the process of apparent competition pigs indirectly facilitated the decline in foxes. As a consequence, both pigs and eagles had to be removed to recover the critically endangered fox. Complete removal of pigs was problematic: removing pigs first could force eagles to concentrate on the remaining foxes, increasing their probability of extinction. Removing eagles first was difficult: eagles are not easily captured and lethal removal was politically distasteful.

Methodology/Principal Findings

Using prey remains collected from eagle nests both before and after the eradication of pigs, we show that one pair of eagles that eluded capture did indeed focus more on foxes. These results support the premise that if the threat of eagle predation had not been mitigated prior to pig removal, fox extinction would have been a more likely outcome.

Conclusions/Significance

If complete eradication of all interacting invasive species is not possible, the order in which they are removed requires careful consideration. If overlooked, unexpected consequences may result that could impede restoration.     

Why the Long Face? The Mechanics of Mandibular Symphysis Proportions in Crocodiles

Background

Crocodilians exhibit a spectrum of rostral shape from long snouted (longirostrine), through to short snouted (brevirostrine) morphologies. The proportional length of the mandibular symphysis correlates consistently with rostral shape, forming as much as 50% of the mandible’s length in longirostrine forms, but 10% in brevirostrine crocodilians. Here we analyse the structural consequences of an elongate mandibular symphysis in relation to feeding behaviours.

Methods/Principal Findings

Simple beam and high resolution Finite Element (FE) models of seven species of crocodile were analysed under loads simulating biting, shaking and twisting. Using beam theory, we statistically compared multiple hypotheses of which morphological variables should control the biomechanical response. Brevi- and mesorostrine morphologies were found to consistently outperform longirostrine types when subject to equivalent biting, shaking and twisting loads. The best predictors of performance for biting and twisting loads in FE models were overall length and symphyseal length respectively; for shaking loads symphyseal length and a multivariate measurement of shape (PC1– which is strongly but not exclusively correlated with symphyseal length) were equally good predictors. Linear measurements were better predictors than multivariate measurements of shape in biting and twisting loads. For both biting and shaking loads but not for twisting, simple beam models agree with best performance predictors in FE models.

Conclusions/Significance

Combining beam and FE modelling allows a priori hypotheses about the importance of morphological traits on biomechanics to be statistically tested. Short mandibular symphyses perform well under loads used for feeding upon large prey, but elongate symphyses incur high strains under equivalent loads, underlining the structural constraints to prey size in the longirostrine morphotype. The biomechanics of the crocodilian mandible are largely consistent with beam theory and can be predicted from simple morphological measurements, suggesting that crocodilians are a useful model for investigating the palaeobiomechanics of other aquatic tetrapods.     

Animal models of PD: pieces of the same puzzle?

Parkinson's disease (PD) is a common neurodegenerative disorder with no known cure. The etiology of PD is likely due, in part, to combinations of genetic susceptibilities and environmental factors. In rare familial cases, PD is due to genetic mutations. A number of new genetic and toxin models of PD and advances in older models are yielding important new information about the pathogenesis of PD. This has prompted us to critically review the current animal models for PD and discuss how these models may yield fresh insights into the pathogenesis of PD, as well as new therapeutic opportunities.     

Should Consensus Be ‘The Commission Method’ in the US? The Perspective of the Federal Advisory Committee Act,Regulations, and Case Law

This paper examines the drive for consensus from the perspective of the good government framework for federal advisory commissions in the United States. Specifically, the paper examines the Federal Advisory Committee Act (FACA)--the statute, its regulations, and case law. It shows that the FACA was intended to be an antidote to abuses in consensus-making processes, including the failure to fully include competing views on commissions. The index of suspicion in the FACA scheme rises when a group work product--including a consensus report--is to be the basis of recommendations to federal officials. Once FACA's requirements regarding committee composition are satisfied, the index of suspicion drops and FACA is indifferent to consensus-making; but the conditions for informed, meaningful participation apply to members who dissent from, as well as those who participate in, consensus. In negotiated rulemaking, the push for consensus and closure creates unacceptable tension with the good government goals of openness and accountability. Proponents of consensus-only bioethics commissions can learn from FACA-related legislative, agency, and judicial insights that consensus-seeking is not always desired by government officials; is rarely cost free; and that diversity and dissent enhance openness, accountability, and fairness. The burden of proof is therefore on proponents of a consensus-only standard for bioethics commissions to demonstrate that a drive for consensus furthers sound decision-making by government officials more than it sets back openness and accountability to a diverse public.     

What Capabilities for the Animal?

In this essay, I defend a bi-constructivist approach to ethology—a constructivist ethology assuming that each animal adopts constructivist strategies. I put it in opposition to what I call a realist-Cartesian approach, which is currently the dominant approach to ethology and comparative psychology. The starting point of the bi-constructivist approach can be formulated as a shift from the classical Aristotelian question “What is an animal?” to the Spinozean question, which is much less classical but which seems to me to be much stronger: “What are the capacities of the animal?”. Is it possible to conceptualize an ethology which insists on interpretation and therefore on invention, innovation and creativity, rather than on causality, the monotony of behavioural routines, and/or genetic or environmental determination? Such an ethology would be based not on the fiction of an absent observer but on fully recognizing the necessity of an observer, who is effectively present in order to get an observation. A pluralistic ethology does not dissociate itself from the marginal epistemologies of practitioners like animal trainers, hunters, stockbreeders etc., or, moreover, non-western experts. An ethology of this kind is not clamped within the boundaries of purely academic epistemology, obsessed by demarcation lines between the human and the animal. My work on the bi-constructivist approach represents a contribution towards the elaboration of an authentically biosemiotic ethology, one which is significantly different from the mechanical ethology of today.     

The making of ethology: The association for the Study of Animal Behaviour, 1936–1986

The paper reviews the history of the Association for the Study of Animal Behaviour in its 50th anniversary year. Having discussed the founding of the Institute for the Study of Animal Behaviour in 1936, the paper establishes its principal aims, follows its fortunes before and during the war, traces its role in the expansion and institutionalization of ethology in Britainbetween 1945 and 1950, and summarizes its transformation into a flourishing scientific society in the 1950s and 1960s. It is concluded that the history of the Association is, to a striking extent, a microcosm of the making of ethology as a successful scientific discipline.     

Vulnerable Subjects? The Case of Nonhuman Animals in Experimentation

The concept of vulnerability is deployed in bioethics to, amongst other things, identify and remedy harms to participants in research, yet although nonhuman animals in experimentation seem intuitively to be vulnerable, this concept and its attendant protections are rarely applied to research animals. I want to argue, however, that this concept is applicable to nonhuman animals and that a new taxonomy of vulnerability developed in the context of human bioethics can be applied to research animals. This taxonomy does useful explanatory work, helping to pinpoint the limitations of the 3Rs/welfare approach currently adopted in the context of animal experimentation. On this account, the 3Rs/welfare approach fails to deliver for nonhuman animals in experimentation because it effectively addresses only one element of their vulnerability (inherent) and paradoxically through the institution of Animal Ethics Committees intended to protect experimental animals in fact generates new vulnerabilities that exacerbate their already precarious situation.     

Why are Asian-Americans educationally hyper-selected? The case of Taiwan

Several Asian-American groups are more educated than their non-migrant compatriots in Asia and their native-born white competitors in America. Lee and Zhou show that this “educational hyper-selectivity” has significant implications for the socio-economic success of Asian immigrants and their children. But they devote relatively little attention to its causes. This paper develops an answer in the Taiwan case. Using interviews and statistics, it shows that the Taiwanese secured an educational advantage because those arriving before 1965 consisted almost entirely of graduate students. Although they entered on student visas, prevailing political and economic conditions led them to settle in the U.S. After the passage of the Hart–Celler Act, these movers reproduced their advantage by sponsoring the arrival of kin, most of whom were also well-educated. The paper’s conclusion assesses the ability of American immigration law to foster the formation of hyper-selected groups.     

Why *-ling-in? The pertinacity of a wrong gender

Co-occurrence restrictions among affixes are preferably accounted for through general structural constraints, to do with separations of word-internal domains, with hierarchical rankings of the affixes involved, with processing complexity, or with word-prosodic patterns. Disallowing particular designated affixes to combine with one another by (language-particular) stipulation is considered a theoretical option only to be taken as a last resort. Against this backdrop it is argued here that in the much-discussed German case of diminutive-pejorative-absolutive suffix -ling the preclusion of further derivational affixation, in particular suffixation with feminine motional -in, is not due to any such general constraint; rather, this must be recognised as an instance of an affix-specific selectional restriction of a morphosemantic kind. The chief theoretical interest of this particular case is diachronic. While inner suffix -ling, originally a semantically neutral nominalising suffix, was able to acquire a diminutive, pejorative, absolutive-aligned (??passive??) semantics, its original gender remained masculine rather than changing to neuter, as would be semantically more suitable. Thus, with the outer, feminine-deriving suffix -in being sensitive to the gender of its nominal bases, nouns which are formally masculine, as required by -in suffixation, but on semantic grounds ought to be neuter are infelicitous.