Genomic correlates of relationship QTL involved in fore- versus hind limb divergence in mice.

Divergence of serially homologous elements of organisms is a common evolutionary pattern contributing to increased phenotypic complexity. Here, we study the genomic intervals affecting the variational independence of fore- and hind limb traits within an experimental mouse population. We use an advanced intercross of inbred mouse strains to map the loci associated with the degree of autonomy between fore- and hind limb long bone lengths (loci affecting the relationship between traits, relationship quantitative trait loci [rQTL]).

The cognitive life of mechanical molecular models.

The use of physical models of molecular structures as research tools has been central to the development of biochemistry and molecular biology. Intriguingly, it has received little attention from scholars of science. In this paper, I argue that these physical models are not mere three-dimensional representations but that they are in fact very special research tools: they are cognitive augmentations.

Morphological integration in the hominin dentition: evolutionary, developmental, and functional factors.

As the most common and best preserved remains in the fossil record, teeth are central to our understanding of evolution. However, many evolutionary analyses based on dental traits overlook the constraints that limit dental evolution. These constraints are diverse, ranging from developmental interactions between the individual elements of a homologous series (the whole dentition) to functional constraints related to occlusion.

Asymmetry in antennal contacts during trophallaxis in ants.

Behavioural and brain left-right asymmetries are a common feature among the animal kingdom. Lateralization often manifests itself at the population-level with most individuals showing the same direction of lateral bias. Theoretical model based on evolutionary stable strategy predicts that lateralization at the population-level is more likely to characterize social rather than solitary species.

Left-right asymmetries of behaviour and nervous system in invertebrates.

Evidence of left-right asymmetries in invertebrates has begun to emerge, suggesting that lateralization of the nervous system may be a feature of simpler brains as well as more complex ones. A variety of studies have revealed sensory and motor asymmetries in behaviour, as well as asymmetries in the nervous system, in invertebrates. Asymmetries in behaviour are apparent in olfaction (antennal asymmetries) and in vision (preferential use of the left or right visual hemifield during activities such as foraging or escape from predators) in animals as different as bees, fruitflies, cockroaches, octopuses, locusts, ants, spiders, crabs, snails, water bugs and cuttlefish.

The concept of mechanism in biology.

The concept of mechanism in biology has three distinct meanings. It may refer to a philosophical thesis about the nature of life and biology ('mechanicism'), to the internal workings of a machine-like structure ('machine mechanism'), or to the causal explanation of a particular phenomenon ('causal mechanism'). In this paper I trace the conceptual evolution of 'mechanism' in the history of biology, and I examine how the three meanings of this term have come to be featured in the philosophy of biology, situating the new 'mechanismic program' in this context.

Natural sources of normativity.

Normativity is widely regarded as being naturalistically problematic. Teleosemantic theories aimed to provide a naturalistic grounding for the normativity of mental representation in biological proper function, but have been subject to a variety of criticisms and would in any case provide only a thin naturalist platform for grounding normativity more generally. Here I present an account that identifies a basic form of valuational normativity in autonomous systems, and show how the account can be extended to encompass key aspects of the normativity of functions and practical reasons.

Scientific perspectivism: A philosopher of science's response to the challenge of big data biology.

Big data biology-bioinformatics, computational biology, systems biology (including 'omics'), and synthetic biology-raises a number of issues for the philosophy of science. This article deals with several such: Is data-intensive biology a new kind of science, presumably post-reductionistic? To what extent is big data biology data-driven? Can data 'speak for themselves?' I discuss these issues by way of a reflection on Carl Woese's worry that "a society that permits biology to become an engineering discipline, that allows that science to slip into the role of changing the living world without trying to understand it, is a danger to itself." And I argue that scientific perspectivism, a philosophical stance represented prominently by Giere, Van Fraassen, and Wimsatt, according to which science cannot as a matter of principle transcend our human perspective, provides the best resources currently at our disposal to tackle many of the philosophical issues implied in the modeling of complex, multilevel/multiscale phenomena.

It's all in your head: the role of quantity estimation in sperm competition.

The study of animal cognition has provided valuable data throughout the years, yet its reliance on laboratory work leaves some open questions. The main question is whether animals employ cognition in daily decision-making. The following discussion uses sperm competition (SC) as a test case for demonstrating the effect of cognition on routine choices, in this case, sexual selection.

A geometric morphometric analysis of hominin upper premolars. Shape variation and morphological integration.

This paper continues the series of articles initiated in 2006 that analyse hominin dental crown morphology by means of geometric morphometric techniques. The detailed study of both upper premolar occlusal morphologies in a comprehensive sample of hominin fossils, including those coming from the Gran Dolina-TD6 and Sima de los Huesos sites from Atapuerca, Spain, complement previous works on lower first and second premolars and upper first molars. A morphological gradient consisting of the change from asymmetric to symmetric upper premolars and a marked reduction of the lingual cusp in recent Homo species has been observed in both premolars.

Origins of brain asymmetry: lateralization of odour memory recall in primitive Australian stingless bees.

Left-right antennal asymmetry has been reported in honeybees. We studied primitive social bees to investigate the evolutionary origins of the asymmetry. Three species of Australian native, stingless bees (Trigona carbonaria, Trigona hockingsi and Austroplebeia australis) were trained to discriminate two odours, lemon (+)/vanilla (-), using the Proboscis Extension Reflex (PER).

Evolutionary novelties and losses in geometric morphometrics: a practical approach through hominin molar morphology.

Geometric morphometric techniques may offer a promising methodological approach to analyze evolutionary novelties in a quantitative framework. Nevertheless, and despite continuous improvements to this methodology, the inclusion of novel features in these studies presents some difficulties. In the present study, different methods to explicitly include novel traits in geometric morphometric analyses are compared, including homology-free approaches, landmark-based approaches, and combinations of both techniques.

The ontogenetic trajectory of the phenotypic covariance matrix, with examples from craniofacial shape in rats and humans.

Many classic quantitative genetic theories assume the covariance structure among adult phenotypic traits to be relatively static during evolution. But the cross-sectional covariance matrix arises from the joint variation of a large range of developmental processes and hence is not constant over the period during which a population of developing organisms is actually exposed to selection. To examine how development shapes the phenotypic covariance structure, we ordinate the age-specific covariance matrices of shape coordinates for craniofacial growth in rats and humans.

Does Octopus vulgaris have preferred arms?

Previous behavioral studies in Octopus vulgaris revealed lateralization of eye use. In this study, the authors expanded the scope to investigate arm preferences. The octopus's generalist hunting lifestyle and the structure of their arms suggest that these animals have no need to designate specific arms for specific tasks.

Contrasting activity patterns of two related octopus species, Octopus macropus and Octopus vulgaris.

Octopus macropus and Octopus vulgaris have overlapping habitats and are exposed to similar temporal changes. Whereas the former species is described as nocturnal in the field, there are conflicting reports about the activity time of the latter one. To compare activity patterns, the authors tested both species in the laboratory.

When do octopuses play? Effects of repeated testing, object type, age, and food deprivation on object play in Octopus vulgaris.

Studying play behavior in octopuses is an important step toward understanding the phylogenetic origins and function of play as well as the cognitive abilities of invertebrates. Fourteen Octopus vulgaris (7 subadults and 7 adults) were presented 2 Lego objects and 2 different food items on 7 consecutive days under 2 different levels of food deprivation. Nine subjects showed play-like behavior with the Lego objects.

Octopus arm choice is strongly influenced by eye use.

This study aims to investigate the octopus' eye and arm coordination and raises the question if visual guidance determines choice of arm use. Octopuses possess eight seemingly identical arms but have recently been reported to show a preference as to which arm they use to initiate contact with objects. These animals also exhibit lateralized eye use, therefore, a connection between eye and arm preference seems possible.

August Rauber (1841-1917): from the primitive streak to Cellularmechanik.

In the early 19th century Karl Ernst von Baer initiated a new research program searching for the mechanisms by which an egg transforms itself into an embryo. August Rauber (1841-1917) took up this challenge. He considered the phylogenetic principle as the right tool to explain the similitude of embryogenetic processes.

A new mark test for mirror self-recognition in non-human primates.

For 30 years Gallup's (Science 167:86-87, 1970) mark test, which consists of confronting a mirror-experienced test animal with its own previously altered mirror image, usually a color mark on forehead, eyebrow or ear, has delivered valuable results about the distribution of visual self-recognition in non-human primates. Chimpanzees, bonobos, orangutans and, less frequently, gorillas can learn to correctly understand the reflection of their body in a mirror. However, the standard version of the mark test is good only for positively proving the existence of self-recognition.

The virtue of being too early: Paul A. Weiss and 'axonal transport'.

The essay introduces how Paul A. Weiss (1898-1989) analyzed his data on neuronal outgrowth and axonal transport, supported by constriction experiments of thousands of living mature nerve fibers. At the University of Chicago his group measured the steady proximo-distal flow of nerve fibers.

Introduction to 'picturing eggs, embryos and cells'.

Some twenty years ago, the historian of technology Henri Michel, who studied the history of instruments, wanted to draw our attention to the images des sciences (Michel 1977). Obviously, an instrument historian is well trained in dealing with pictorial matter, whether it may be blueprints of instruments, or detailed instructions about how to use and improve them. Further, instruments are extremely well suited media to demonstrate that theoretical knowledge has to be practically acquired, whether by making instruments, or by hand drawings.

Hemispheric processing of landmark and geometric information in male and female domestic chicks (Gallus gallus).

A place learning paradigm was used to assess lateralisation and sex differences in domestic chicks dealing with global (geometric shape) and local (identity of a beacon) aspects of spatial encoding. Male and female domestic chicks were trained binocularly to localise food buried under sawdust in the centre of a square-shaped enclosure. They were then tested binocularly and monocularly (Experiment 1).

Generalization in place learning and geometry knowledge in rats.

Rats were trained to search for a food reward hidden under sawdust in the center of a square-shaped enclosure designed to force orientation on the basis of the overall geometry of the environment. They were then tested in a number of enclosures differing in shape and in size (rectangular-, double-side square-, and equilateral triangle-shaped enclosures). Results showed that rats transferred their place-finding ability to the novel enclosures.