Global change alters the stability of food webs

Recent research has generally shown that a small change in the number of species in a food web can have consequences both for community structure and ecosystem processes. However ‘change’ is not limited to just the number of species in a community, but might include an alteration to such properties as precipitation, nutrient cycling and temperature. How such changes might affect species interactions is important, not just through the presence or absence of interactions, but also because the patterning of interaction strengths among species is intimately associated with community stability. Interaction strengths encompass such properties as feeding rates and assimilation efficiencies, and encapsulate functionally important information with regard to ecosystem processes. Interaction strengths represent the pathways and transfer of energy through an ecosystem. We review the best empirical data available detailing the frequency distribution of interaction strengths in communities. We present the underlying (but consistent) pattern of species interactions and discuss the implications of this patterning. We then examine how such a basic pattern might be affected given various scenarios of ‘change’ and discuss the consequences for community stability and ecosystem functioning.     

Functional imaging of the auditory processing applied to speech sounds

In this paper, we describe domain-general auditory processes that we believe are prerequisite to the linguistic analysis of speech. We discuss biological evidence for these processes and how they might relate to processes that are specific to human speech and language. We begin with a brief review of (i) the anatomy of the auditory system and (ii) the essential properties of speech sounds. Section 4 describes the general auditory mechanisms that we believe are applied to all communication sounds, and how functional neuroimaging is being used to map the brain networks associated with domain-general auditory processing. Section 5 discusses recent neuroimaging studies that explore where such general processes give way to those that are specific to human speech and language.     

The theater management model of plant memory

The existence of a memory in plants raises several fundamental questions. What might be the function of a plant memory? How might it work? Which molecular mechanisms might be responsible? Here, we sketch out the landscape of plant memory with particular reference to the concepts of functioning-dependent structures and competitive coherence. We illustrate how these concepts might be relevant with reference to the metaphor of a traveling, avant-garde theater company and we suggest how using a program that simulates competitive coherence might help answer some of the questions about plant memory.     

Language Ideology and Women's Speech: Talking Community in the Northwest Amazon

Taking the Northwest Amazon of Brazil as its example, this article argues for the analytic concept of a "speech culture," combining, but heuristically separating, speech practice and language ideology. In the Northwest Amazon, an ideology of language establishes an equivalence between linguistic performance and descent group belonging. In contrast to the fixed, normative notions of groupness, this article explores the dynamic construction of social relations through women's ritualized wept greeting speech. In these interactions, linguistic differentiation is countered by the experience of a single speech act based upon shared principles with organized participation in and by different linguistic codes. Through the collaborative nature of the speech act a common ground is produced and revealed. The community in this sense emerges as a cultural artifact whose production is largely the work of women. Through these speech interactions—of similar sentiments and meanings across different linguistic codes—women of the Northwest Amazon construct a community of talk. [Keywords: women, laments, language, Amazonia]     

The invader,the enemy within and they-who-must-not-be-named: how police talk about minorities in Italy,the Netherlands and France

How people talk about ethnic minorities is a sensitive subject, especially in law enforcement. We know little about it as far as continental Europe is concerned. This article is about how police officers talk about minorities in France, in Italy and in the Netherlands. How do speech norms (‘political correctness’) apply outside the anglophone world? Is there a relation between speech norms and practices? This exploratory study is based on interviews with fifty-five police officers from France, Italy and the Netherlands. In these countries, police officers are aware that displaying overt racism is not socially desirable. Interviews show that there are vastly different speech norms governing decent race talk in the three countries. Specifically, we compare: how police use ethnic categories; how police anticipate accusations of discrimination; and how police theorize the over-representation of ethnic minorities in crime. French respondents respect much stricter speech norms than Dutch or Italian ones.     

The rate of environmental fluctuations shapes ecological dynamics in a two‐species microbial system

Species interactions change when the external conditions change. How these changes affect microbial community properties is an open question. We address this question using a two‐species consortium in which species interactions change from exploitation to competition depending on the carbon source provided. We built a mathematical model and calibrated it using single‐species growth measurements. This model predicted that low frequencies of change between carbon sources lead to species loss, while intermediate and high frequencies of change maintained both species. We experimentally confirmed these predictions by growing co‐cultures in fluctuating environments. These findings complement more established concepts of a diversity peak at intermediate disturbance frequencies. They also provide a mechanistic understanding for how the dynamics at the community level emerges from single‐species behaviours and interspecific interactions. Our findings suggest that changes in species interactions can profoundly impact the ecological dynamics and properties of microbial systems.     

The Genetic Code: What Is It Good For? An Analysis of the Effects of Selection Pressures on Genetic Codes

How did the ``universal' genetic code arise? Several hypotheses have been put forward, and the code has been analyzed extensively by authors looking for clues to selection pressures that might have acted during its evolution. But this approach has been ineffective. Although an impressive number of properties has been attributed to the universal code, it has been impossible to determine whether selection on any of these properties was important in the code's evolution or whether the observed properties arose as a consequence of selection on some other characteristic. Therefore we turned the question around and asked, what would a genetic code look like if it had evolved in response to various different selection pressures? To address this question, we constructed a genetic algorithm. We found first that selecting on a particular measure yields codes that are similar to each other. Second, we found that the universal code is far from minimized with respect to the effects of mutations (or translation errors) on the amino acid compositions of proteins. Finally, we found that the codes that most closely resembled real codes were those generated by selecting on aspects of the code's structure, not those generated by selecting to minimize the effects of amino acid substitutions on proteins. This suggests that the universal genetic code has been selected for a particular structure—a structure that confers an important flexibility on the evolution of genes and proteins—and that the particular assignments of amino acids to codons are secondary. Received: 29 December 1998 / Accepted: 8 July 1999     

How to build an information gathering and processing system: lessons from naturally and artificially intelligent systems

Imagine a situation in which you had to design a physical agent that could collect information from its environment, then store and process that information to help it respond appropriately to novel situations. What kinds of information should it attend to? How should the information be represented so as to allow efficient use and re-use? What kinds of constraints and trade-offs would there be? There are no unique answers. In this paper, we discuss some of the ways in which the need to be able to address problems of varying kinds and complexity can be met by different information processing systems. We also discuss different ways in which relevant information can be obtained, and how different kinds of information can be processed and used, by both biological organisms and artificial agents. We analyse several constraints and design features, and show how they relate both to biological organisms, and to lessons that can be learned from building artificial systems. Our standpoint overlaps with Karmiloff-Smith (1992) in that we assume that a collection of mechanisms geared to learning and developing in biological environments are available in forms that constrain, but do not determine, what can or will be learnt by individuals.     

Effects of Early Bilingual Experience with a Tone and a Non-Tone Language on Speech-Music Integration

We investigated music and language processing in a group of early bilinguals who spoke a tone language and a non-tone language (Cantonese and Dutch). We assessed online speech-music processing interactions, that is, interactions that occur when speech and music are processed simultaneously in songs, with a speeded classification task. In this task, participants judged sung pseudowords either musically (based on the direction of the musical interval) or phonologically (based on the identity of the sung vowel). We also assessed longer-term effects of linguistic experience on musical ability, that is, the influence of extensive prior experience with language when processing music. These effects were assessed with a task in which participants had to learn to identify musical intervals and with four pitch-perception tasks. Our hypothesis was that due to their experience in two different languages using lexical versus intonational tone, the early Cantonese-Dutch bilinguals would outperform the Dutch control participants. In online processing, the Cantonese-Dutch bilinguals processed speech and music more holistically than controls. This effect seems to be driven by experience with a tone language, in which integration of segmental and pitch information is fundamental. Regarding longer-term effects of linguistic experience, we found no evidence for a bilingual advantage in either the music-interval learning task or the pitch-perception tasks. Together, these results suggest that being a Cantonese-Dutch bilingual does not have any measurable longer-term effects on pitch and music processing, but does have consequences for how speech and music are processed jointly.     

A “Living” Machine

Biomimetics (or bionics) is the engineering discipline that constructs artificial systems using biological principles. The ideal final result in biomimetics is to create a living machine. But what are the desirable and non-desirable properties of biomimetic product7 Where can natural prototypes be found7 How can technical solutions be transferred from nature to technology? Can we use living nature like LEC, O bricks for oonstmction our machines? How can biology help us? What is a living machine? In biomimetic practice only some “part“ (organ, part of organ, tissue) of the observed whole organism is utilized. A possible template for future super-organism extension for biornimetic methods might be drawn from experiments in holistic ecological agriculture (ecological design, permacuhure, ecological engineering, etc. ). The necessary translation of these roles to practical action can be achieved with the Russian Theory of Inventive Problem Solving (TRIZ), specifically adjusted to biology. Thus, permaculture, reinforced by a TRIZ conceptual framework, might provide the basis for Super-Organismic Bionics, which is hypothesized as necessary for effective ecological engineering. This hypothesis is supported by a case study-the design of a sustainable artificial nature reserve for wild pollinators as a living machine.     

The library in the digital age

Electronic publication is an increasingly popular forum within the scientific community, and many are talking about the possibility of dispensing with paper publications entirely in years to come. How likely is this to happen, and if so how quickly? What will be its impact on the way we use and contribute to the scientific knowledge base? This article discusses the elements of today's digital library and how they might evolve as we confront the online world.     

Biology of human speech communication

In this paper the analysis of the human acoustic communication channel is presented as a potentially bio-anthropological subject of interest. After a crude survey concerning some important aspects of speech and expressive behaviour a hypothesis is outlined saying that the verbal and the nonverbal content of the speech signal are not just transferred side by side; rather there exist close interconnections between the linguistic and the expressive structures, which is shown regarding the speech melody; the 'cultural' language code makes use of a predominantly 'non-cultural' code of vocalisations for the purpose of linguistic disambiguation and speeding up the communication process. The complementarity of these two codes, their principal independence of each other as well as their different cerebral representation contribute to the high efficiency of speech as a communication tool.     

Profiling the extended phenotype of plant pathogens

One of the most fundamental questions in plant pathology is what determines whether a pathogen grows within a plant? This question is frequently studied in terms of the role of elicitors and pathogenicity factors in the triggering or overcoming of host defences. However, this focus fails to address the basic question of how the environment in host tissues acts to support or restrict pathogen growth. Efforts to understand this aspect of host–pathogen interactions are commonly confounded by several issues, including the complexity of the plant environment, the artificial nature of many experimental infection systems and the fact that the physiological properties of a pathogen growing in association with a plant can be very different from the properties of the pathogen in culture. It is also important to recognize that the phenotype and evolution of pathogen and host are inextricably linked through their interactions, such that the environment experienced by a pathogen within a host, and its phenotype within the host, is a product of both its interaction with its host and its evolutionary history, including its co‐evolution with host plants. As the phenotypic properties of a pathogen within a host cannot be defined in isolation from the host, it may be appropriate to think of pathogens as having an ‘extended phenotype’ that is the product of their genotype, host interactions and population structure within the host environment. This article reflects on the challenge of defining and studying this extended phenotype, in relation to the questions posed below, and considers how knowledge of the phenotype of pathogens in the host environment could be used to improve disease control.

• What determines whether a pathogen grows within a plant?
• What aspects of pathogen biology should be considered in describing the extended phenotype of a pathogen within a host?
• How can we study the extended phenotype in ways that provide insights into the phenotypic properties of pathogens during natural infections?

     

Ecological realism and mechanisms by which diversity begets stability

We investigated how ecological realism might impact the outcome of three experimental manipulations of species richness to determine whether the patterns and the mechanisms underlying richness–variability relationships differ as ecological communities are increasingly exposed to external forces that may drive richness–variability patterns in nature. To test for such an effect, we conducted experiments using rock pool meio‐invertebrate communities housed in three experimental venues: controlled laboratory microcosms, artificially constructed rock pools in the field, and naturally occurring rock pools in the field. Our results showed that experimental venue can have a strong effect on the outcome of richness manipulation experiments. As ecological realism increased, the strength of the relationship between species richness and community variability declined from 32.9% in the laboratory microcosms to 16.8% in the artificial pools to no effect of species richness on community variability in the natural rock pools. The determinants of community variability also differed as ecological realism increased. In laboratory microcosms, community variability was driven solely by mechanisms related to increasing species richness. In artificial rock pools, community variability was driven by a combination of direct and indirect environmental factors as well as mechanisms related to increasing species richness. In the natural rock pools community variability was independent of species richness and was only related to environmental factors. In summary, we found that stabilizing mechanisms associated with species interactions were influential in establishing species richness–variability relations only in the less realistic experimental venues (the laboratory microcosms and the artificial rock pools in the field), and that these mechanisms diminished in importance as ecological realism and complexity of the experimental venue increased. Our results suggest that the effects of diversity might be more difficult to detect in natural systems due to the combined effects of biotic and abiotic forcing, which can mask our ability to detect richness effects.     

Speaker Input Variability Does Not Explain Why Larger Populations Have Simpler Languages

A learner’s linguistic input is more variable if it comes from a greater number of speakers. Higher speaker input variability has been shown to facilitate the acquisition of phonemic boundaries, since data drawn from multiple speakers provides more information about the distribution of phonemes in a speech community. It has also been proposed that speaker input variability may have a systematic influence on individual-level learning of morphology, which can in turn influence the group-level characteristics of a language. Languages spoken by larger groups of people have less complex morphology than those spoken in smaller communities. While a mechanism by which the number of speakers could have such an effect is yet to be convincingly identified, differences in speaker input variability, which is thought to be larger in larger groups, may provide an explanation. By hindering the acquisition, and hence faithful cross-generational transfer, of complex morphology, higher speaker input variability may result in structural simplification. We assess this claim in two experiments which investigate the effect of such variability on language learning, considering its influence on a learner’s ability to segment a continuous speech stream and acquire a morphologically complex miniature language. We ultimately find no evidence to support the proposal that speaker input variability influences language learning and so cannot support the hypothesis that it explains how population size determines the structural properties of language.     

Question 6: How Did Translation Occur?

We have not yet reached a generally accepted view on how the genetic code might have originated. What has been proposed so far? The main part of the contribution to the panel discussion was devoted to recall to the audience the chronological order of publications the main aim of which it was, at least theoretically, to somehow connect physico-chemical properties of physically proximal ‘universal adapters’, usually some kind of nucleic acid polymer, with reactive forms of physically proximal amino acids that would subsequently polymerise into polypeptides.     

Perspective on architecture and assembly of membrane contact sites

Membrane contact sites (MCS) are platforms of physical contact between different organelles. They are formed through interactions involving lipids and proteins, and function in processes such as calcium and lipid exchange, metabolism and organelle biogenesis. In this article, we discuss emerging questions regarding the architecture, organisation and assembly of MCS, such as: What is the contribution of different components to the interaction between organelles? How is the specific composition of different types of membrane contacts sites established and maintained? How are proteins and lipids spatially organised at MCS and how does that influence their function? How dynamic are MCS on the molecular and ultrastructural level? We highlight current state of research and point out experimental approaches that promise to contribute to a spatiomechanistic understanding of MCS functions.     

Microevolution in biological control: Mechanisms, patterns, and processes

Microevolution may determine both the safety and efficacy of classical biological control. Despite a growing body of literature, there are several key unanswered questions regarding the role of evolution in biological control: (1) How common is local adaptation of natural enemies to their hosts or the environment in the native range? How critical is it for success of biological control to find locally adapted agents for importation? (2) Does adaptive evolution following introductions play an important role in biological control? (3) Do introductions of biological control agents impose bottlenecks in population size that reduce genetic variation, and is reduced genetic variation associated with low fitness and poor performance? (4) How great is the risk of evolution of host range of biological control agents? (5) What is the risk of target pests evolving resistance to biological control agents? If pests evolve increased resistance, will biological control agents evolve mechanisms to overcome that resistance? Here, we review the four fundamental processes of microevolution, and discuss how they interact in the context of biological control. We discuss our current state of knowledge regarding the outstanding questions, highlight the types of experiments that can address them, and suggest ways to use microevolution to define risks, and enhance efficacy and safety of biological control.     

Monitoring change in biodiversity through composite indices

The need to monitor trends in biodiversity raises many technical issues. What are the features of a good biodiversity index? How should trends in abundance of individual species be estimated? How should composite indices, possibly spanning very diverse taxa, be formed? At what spatial scale should composite indices be applied? How might change-points--points at which the underlying trend changes--be identified? We address some of the technical issues underlying composite indices, including survey design, weighting of the constituent indices, identification of change-points and estimation of spatially varying time trends. We suggest some criteria that biodiversity measures for use in monitoring surveys should satisfy, and we discuss the problems of implementing rigorous methods. We illustrate the properties of different composite indices using UK farmland bird data. We conclude that no single index can capture all aspects of biodiversity change, but that a modified Shannon index and the geometric mean of relative abundance have useful properties.