当前期刊: Biological Reviews Go to current issue    加入关注   
显示样式:        排序: 导出
我的关注
我的收藏
您暂时未登录!
登录
  • Development and evolution of the tetrapod skull–neck boundary
    Biol. Rev. (IF 10.288) Pub Date : 2020-01-07
    Hillary C. Maddin; Nadine Piekarski; Robert R. Reisz; James Hanken

    The origin and evolution of the vertebrate skull have been topics of intense study for more than two centuries. Whereas early theories of skull origin, such as the influential vertebral theory, have been largely refuted with respect to the anterior (pre‐otic) region of the skull, the posterior (post‐otic) region is known to be derived from the anteriormost paraxial segments, i.e. the somites. Here we review the morphology and development of the occiput in both living and extinct tetrapods, taking into account revised knowledge of skull development by augmenting historical accounts with recent data. When occipital composition is evaluated relative to its position along the neural axis, and specifically to the hypoglossal nerve complex, much of the apparent interspecific variation in the location of the skull–neck boundary stabilizes in a phylogenetically informative way. Based on this criterion, three distinct conditions are identified in (i) frogs, (ii) salamanders and caecilians, and (iii) amniotes. The position of the posteriormost occipital segment relative to the hypoglossal nerve is key to understanding the evolution of the posterior limit of the skull. By using cranial foramina as osteological proxies of the hypoglossal nerve, a survey of fossil taxa reveals the amniote condition to be present at the base of Tetrapoda. This result challenges traditional theories of cranial evolution, which posit translocation of the occiput to a more posterior location in amniotes relative to lissamphibians (frogs, salamanders, caecilians), and instead supports the largely overlooked hypothesis that the reduced occiput in lissamphibians is secondarily derived. Recent advances in our understanding of the genetic basis of axial patterning and its regulation in amniotes support the hypothesis that the lissamphibian occipital form may have arisen as the product of a homeotic shift in segment fate from an amniote‐like condition.

    更新日期:2020-01-08
  • Ant‐termite interactions: an important but under‐explored ecological linkage
    Biol. Rev. (IF 10.288) Pub Date : 2019-12-25
    Jiri Tuma; Paul Eggleton; Tom M. Fayle

    Animal interactions play an important role in understanding ecological processes. The nature and intensity of these interactions can shape the impacts of organisms on their environment. Because ants and termites, with their high biomass and range of ecological functions, have considerable effects on their environment, the interaction between them is important for ecosystem processes. Although the manner in which ants and termites interact is becoming increasingly well studied, there has been no synthesis to date of the available literature. Here we review and synthesise all existing literature on ant–termite interactions. We infer that ant predation on termites is the most important, most widespread, and most studied type of interaction. Predatory ant species can regulate termite populations and subsequently slow down the decomposition of wood, litter and soil organic matter. As a consequence they also affect plant growth and distribution, nutrient cycling and nutrient availability. Although some ant species are specialised termite predators, there is probably a high level of opportunistic predation by generalist ant species, and hence their impact on ecosystem processes that termites are known to provide varies at the species level. The most fruitful future research direction will be to evaluate the impact of ant–termite predation on broader ecosystem processes. To do this it will be necessary to quantify the efficacy both of particular ant species and of ant communities as a whole in regulating termite populations in different biomes. We envisage that this work will require a combination of methods, including DNA barcoding of ant gut contents along with field observations and exclusion experiments. Such a combined approach is necessary for assessing how this interaction influences entire ecosystems.

    更新日期:2019-12-27
  • 5′ untranslated regions: the next regulatory sequence in yeast synthetic biology
    Biol. Rev. (IF 10.288) Pub Date : 2019-12-20
    Yatti De Nijs; Sofie L. De Maeseneire; Wim K. Soetaert

    When developing industrial biotechnology processes, Saccharomyces cerevisiae (baker's yeast or brewer's yeast) is a popular choice as a microbial host. Many tools have been developed in the fields of synthetic biology and metabolic engineering to introduce heterologous pathways and tune their expression in yeast. Such tools mainly focus on controlling transcription, whereas post‐transcriptional regulation is often overlooked. Herein we discuss regulatory elements found in the 5′ untranslated region (UTR) and their influence on protein synthesis. We provide not only an overall picture, but also a set of design rules on how to engineer a 5′ UTR. The reader is also referred to currently available models that allow gene expression to be tuned predictably using different 5′ UTRs.

    更新日期:2019-12-21
  • Cardiovascular shunting in vertebrates: a practical integration of competing hypotheses
    Biol. Rev. (IF 10.288) Pub Date : 2019-12-20
    Warren Burggren; Renato Filogonio; Tobias Wang

    This review explores the long‐standing question: ‘Why do cardiovascular shunts occur?’ An historical perspective is provided on previous research into cardiac shunts in vertebrates that continues to shape current views. Cardiac shunts and when they occur is then described for vertebrates. Nearly 20 different functional reasons have been proposed as specific causes of shunts, ranging from energy conservation to improved gas exchange, and including a plethora of functions related to thermoregulation, digestion and haemodynamics. It has even been suggested that shunts are merely an evolutionary or developmental relic. Having considered the various hypotheses involving cardiovascular shunting in vertebrates, this review then takes a non‐traditional approach. Rather than attempting to identify the single ‘correct’ reason for the occurrence of shunts, we advance a more holistic, integrative approach that embraces multiple, non‐exclusive suites of proposed causes for shunts, and indicates how these varied functions might at least co‐exist, if not actually support each other as shunts serve multiple, concurrent physiological functions. It is argued that deposing the ‘monolithic’ view of shunting leads to a more nuanced view of vertebrate cardiovascular systems. This review concludes by suggesting new paradigms for testing the function(s) of shunts, including experimentally placing organ systems into conflict in terms of their perfusion needs, reducing sources of variation in physiological experiments, measuring possible compensatory responses to shunt ablation, moving experiments from the laboratory to the field, and using cladistics‐related approaches in the choice of experimental animals.

    更新日期:2019-12-20
  • The origins of gestures and language: history, current advances and proposed theories
    Biol. Rev. (IF 10.288) Pub Date : 2019-12-18
    Jacques Prieur; Stéphanie Barbu; Catherine Blois‐Heulin; Alban Lemasson

    Investigating in depth the mechanisms underlying human and non‐human primate intentional communication systems (involving gestures, vocalisations, facial expressions and eye behaviours) can shed light on the evolutionary roots of language. Reports on non‐human primates, particularly great apes, suggest that gestural communication would have been a crucial prerequisite for the emergence of language, mainly based on the evidence of large communication repertoires and their associated multifaceted nature of intentionality that are key properties of language. Such research fuels important debates on the origins of gestures and language. We review here three non‐mutually exclusive processes that can explain mainly great apes' gestural acquisition and development: phylogenetic ritualisation, ontogenetic ritualisation, and learning via social negotiation. We hypothesise the following scenario for the evolutionary origins of gestures: gestures would have appeared gradually through evolution via signal ritualisation following the principle of derived activities, with the key involvement of emotional expression and processing. The increasing level of complexity of socioecological lifestyles and associated daily manipulative activities might then have enabled the acquisition and development of different interactional strategies throughout the life cycle. Many studies support a multimodal origin of language. However, we stress that the origins of language are not only multimodal, but more broadly multicausal. We propose a multicausal theory of language origins which better explains current findings. It postulates that primates' communicative signalling is a complex trait continually shaped by a cost–benefit trade‐off of signal production and processing of interactants in relation to four closely interlinked categories of evolutionary and life cycle factors: species, individual and context‐related characteristics as well as behaviour and its characteristics. We conclude by suggesting directions for future research to improve our understanding of the evolutionary roots of gestures and language.

    更新日期:2019-12-19
  • A niche perspective on the range expansion of symbionts
    Biol. Rev. (IF 10.288) Pub Date : 2019-12-05
    Alexandre Mestre, Robert Poulin, Joaquín Hortal

    Range expansion results from complex eco‐evolutionary processes where range dynamics and niche shifts interact in a novel physical space and/or environment, with scale playing a major role. Obligate symbionts (i.e. organisms permanently living on hosts) differ from free‐living organisms in that they depend on strong biotic interactions with their hosts which alter their niche and spatial dynamics. A symbiotic lifestyle modifies organism–environment relationships across levels of organisation, from individuals to geographical ranges. These changes influence how symbionts experience colonisation and, by extension, range expansion. Here, we investigate the potential implications of a symbiotic lifestyle on range expansion capacity. We present a unified conceptual overview on range expansion of symbionts that integrates concepts grounded in niche and metapopulation theories. Overall, we explain how niche‐driven and dispersal‐driven processes govern symbiont range dynamics through their interaction across scales, from host switching to geographical range shifts. First, we describe a background framework for range dynamics based on metapopulation concepts applied to symbiont organisation levels. Then, we integrate metapopulation processes operating in the physical space with niche dynamics grounded in the environmental arena. For this purpose, we provide a definition of the biotope (i.e. living place) specific to symbionts as a hinge concept to link the physical and environmental spaces, wherein the biotope unit is a metapopulation patch (either a host individual or a land fragment). Further, we highlight the dual nature of the symbionts' niche, which is characterised by both host traits and the external environment, and define proper conceptual variants to provide a meaningful unification of niche, biotope and symbiont organisation levels. We also explore variation across systems in the relative relevance of both external environment and host traits to the symbiont's niche and their potential implications on range expansion. We describe in detail the potential mechanisms by which hosts, through their function as biotopes, could influence how some symbionts expand their range – depending on the life history and traits of both associates. From the spatial point of view, hosts can extend symbiont dispersal range via host‐mediated dispersal, although the requirement for among‐host dispersal can challenge symbiont range expansion. From the niche point of view, homeostatic properties of host bodies may allow symbiont populations to become insensitive to off‐host environmental gradients during host‐mediated dispersal. These two potential benefits of the symbiont–host interaction can enhance symbiont range expansion capacity. On the other hand, the central role of hosts governing the symbiont niche makes symbionts strongly dependent on the availability of suitable hosts. Thus, environmental, dispersal and biotic barriers faced by suitable hosts apply also to the symbiont, unless eventual opportunities for host switching allow the symbiont to expand its repertoire of suitable hosts (thus expanding its fundamental niche). Finally, symbionts can also improve their range expansion capacity through their impacts on hosts, via protecting their affiliated hosts from environmental harshness through biotic facilitation.

    更新日期:2019-12-06
  • Calmodulin‐mediated events during the life cycle of the amoebozoan Dictyostelium discoideum
    Biol. Rev. (IF 10.288) Pub Date : 2019-11-26
    Danton H. O'Day, Sabateeshan Mathavarajah, Michael A. Myre, Robert J. Huber

    This review focusses on the functions of intracellular and extracellular calmodulin, its target proteins and their binding proteins during the asexual life cycle of Dictyostelium discoideum. Calmodulin is a primary regulatory protein of calcium signal transduction that functions throughout all stages. During growth, it mediates autophagy, the cell cycle, folic acid chemotaxis, phagocytosis, and other functions. During mitosis, specific calmodulin‐binding proteins translocate to alternative locations. Translocation of at least one cell adhesion protein is calmodulin dependent. When starved, cells undergo calmodulin‐dependent chemotaxis to cyclic AMP generating a multicellular pseudoplasmodium. Calmodulin‐dependent signalling within the slug sets up a defined pattern and polarity that sets the stage for the final events of morphogenesis and cell differentiation. Transected slugs undergo calmodulin‐dependent transdifferentiation to re‐establish the disrupted pattern and polarity. Calmodulin function is critical for stalk cell differentiation but also functions in spore formation, events that begin in the pseudoplasmodium. The asexual life cycle restarts with the calmodulin‐dependent germination of spores. Specific calmodulin‐binding proteins as well as some of their binding partners have been linked to each of these events. The functions of extracellular calmodulin during growth and development are also discussed. This overview brings to the forefront the central role of calmodulin, working through its numerous binding proteins, as a primary downstream regulator of the critical calcium signalling pathways that have been well established in this model eukaryote. This is the first time the function of calmodulin and its target proteins have been documented through the complete life cycle of any eukaryote.

    更新日期:2019-11-28
  • Fungal functional ecology: bringing a trait‐based approach to plant‐associated fungi
    Biol. Rev. (IF 10.288) Pub Date : 2019-11-25
    Amy E. Zanne, Kessy Abarenkov, Michelle E. Afkhami, Carlos A. Aguilar‐Trigueros, Scott Bates, Jennifer M. Bhatnagar, Posy E. Busby, Natalie Christian, William K. Cornwell, Thomas W. Crowther, Habacuc Flores‐Moreno, Dimitrios Floudas, Romina Gazis, David Hibbett, Peter Kennedy, Daniel L. Lindner, Daniel S. Maynard, Amy M. Milo, Rolf Henrik Nilsson, Jeff Powell, Mark Schildhauer, Jonathan Schilling, Kathleen K. Treseder

    Fungi play many essential roles in ecosystems. They facilitate plant access to nutrients and water, serve as decay agents that cycle carbon and nutrients through the soil, water and atmosphere, and are major regulators of macro‐organismal populations. Although technological advances are improving the detection and identification of fungi, there still exist key gaps in our ecological knowledge of this kingdom, especially related to function. Trait‐based approaches have been instrumental in strengthening our understanding of plant functional ecology and, as such, provide excellent models for deepening our understanding of fungal functional ecology in ways that complement insights gained from traditional and ‐omics‐based techniques. In this review, we synthesize current knowledge of fungal functional ecology, taxonomy and systematics and introduce a novel database of fungal functional traits (FunFun). FunFun is built to interface with other databases to explore and predict how fungal functional diversity varies by taxonomy, guild, and other evolutionary or ecological grouping variables. To highlight how a quantitative trait‐based approach can provide new insights, we describe multiple targeted examples and end by suggesting next steps in the rapidly growing field of fungal functional ecology.

    更新日期:2019-11-26
  • How do herbivorous insects respond to drought stress in trees?
    Biol. Rev. (IF 10.288) Pub Date : 2019-11-21
    Claire Gely, Susan G.W. Laurance, Nigel E. Stork

    Increased frequency and severity of drought, as a result of climate change, is expected to drive critical changes in plant–insect interactions that may elevate rates of tree mortality. The mechanisms that link water stress in plants to insect performance are not well understood. Here, we build on previous reviews and develop a framework that incorporates the severity and longevity of drought and captures the plant physiological adjustments that follow moderate and severe drought. Using this framework, we investigate in greater depth how insect performance responds to increasing drought severity for: (i) different feeding guilds; (ii) flush feeders and senescence feeders; (iii) specialist and generalist insect herbivores; and (iv) temperate versus tropical forest communities. We outline how intermittent and moderate drought can result in increases of carbon‐based and nitrogen‐based chemical defences, whereas long and severe drought events can result in decreases in plant secondary defence compounds. We predict that different herbivore feeding guilds will show different but predictable responses to drought events, with most feeding guilds being negatively affected by water stress, with the exception of wood borers and bark beetles during severe drought and sap‐sucking insects and leaf miners during moderate and intermittent drought. Time of feeding and host specificity are important considerations. Some insects, regardless of feeding guild, prefer to feed on younger tissues from leaf flush, whereas others are adapted to feed on senescing tissues of severely stressed trees. We argue that moderate water stress could benefit specialist insect herbivores, while generalists might prefer severe drought conditions. Current evidence suggests that insect outbreaks are shorter and more spatially restricted in tropical than in temperate forests. We suggest that future research on the impact of drought on insect communities should include (i) assessing how drought‐induced changes in various plant traits, such as secondary compound concentrations and leaf water potential, affect herbivores; (ii) food web implications for other insects and those that feed on them; and (iii) interactions between the effects on insects of increasing drought and other forms of environmental change including rising temperatures and CO2 levels. There is a need for larger, temperate and tropical forest‐scale drought experiments to look at herbivorous insect responses and their role in tree death.

    更新日期:2019-11-21
  • The ecology of chronic wasting disease in wildlife
    Biol. Rev. (IF 10.288) Pub Date : 2019-11-21
    Luis E. Escobar, Sandra Pritzkow, Steven N. Winter, Daniel A. Grear, Megan S. Kirchgessner, Ernesto Dominguez‐Villegas, Gustavo Machado, A. Townsend Peterson, Claudio Soto

    Prions are misfolded infectious proteins responsible for a group of fatal neurodegenerative diseases termed transmissible spongiform encephalopathy or prion diseases. Chronic Wasting Disease (CWD) is the prion disease with the highest spillover potential, affecting at least seven Cervidae (deer) species. The zoonotic potential of CWD is inconclusive and cannot be ruled out. A risk of infection for other domestic and wildlife species is also plausible. Here, we review the current status of the knowledge with respect to CWD ecology in wildlife. Our current understanding of the geographic distribution of CWD lacks spatial and temporal detail, does not consider the biogeography of infectious diseases, and is largely biased by sampling based on hunters' cooperation and funding available for each region. Limitations of the methods used for data collection suggest that the extent and prevalence of CWD in wildlife is underestimated. If the zoonotic potential of CWD is confirmed in the short term, as suggested by recent results obtained in experimental animal models, there will be limited accurate epidemiological data to inform public health. Research gaps in CWD prion ecology include the need to identify specific biological characteristics of potential CWD reservoir species that better explain susceptibility to spillover, landscape and climate configurations that are suitable for CWD transmission, and the magnitude of sampling bias in our current understanding of CWD distribution and risk. Addressing these research gaps will help anticipate novel areas and species where CWD spillover is expected, which will inform control strategies. From an ecological perspective, control strategies could include assessing restoration of natural predators of CWD reservoirs, ultrasensitive CWD detection in biotic and abiotic reservoirs, and deer density and landscape modification to reduce CWD spread and prevalence.

    更新日期:2019-11-21
  • Post‐ejaculatory modifications to sperm (PEMS)
    Biol. Rev. (IF 10.288) Pub Date : 2019-11-18
    Scott Pitnick, Mariana F. Wolfner, Steve Dorus

    Mammalian sperm must spend a minimum period of time within a female reproductive tract to achieve the capacity to fertilize oocytes. This phenomenon, termed sperm ‘capacitation’, was discovered nearly seven decades ago and opened a window into the complexities of sperm–female interaction. Capacitation is most commonly used to refer to a specific combination of processes that are believed to be widespread in mammals and includes modifications to the sperm plasma membrane, elevation of intracellular cyclic AMP levels, induction of protein tyrosine phosphorylation, increased intracellular Ca2+ levels, hyperactivation of motility, and, eventually, the acrosome reaction. Capacitation is only one example of post‐ejaculatory modifications to sperm (PEMS) that are widespread throughout the animal kingdom. Although PEMS are less well studied in non‐mammalian taxa, they likely represent the rule rather than the exception in species with internal fertilization. These PEMS are diverse in form and collectively represent the outcome of selection fashioning complex maturational trajectories of sperm that include multiple, sequential phenotypes that are specialized for stage‐specific functionality within the female. In many cases, PEMS are critical for sperm to migrate successfully through the female reproductive tract, survive a protracted period of storage, reach the site of fertilization and/or achieve the capacity to fertilize eggs. We predict that PEMS will exhibit widespread phenotypic plasticity mediated by sperm–female interactions. The successful execution of PEMS thus has important implications for variation in fitness and the operation of post‐copulatory sexual selection. Furthermore, it may provide a widespread mechanism of reproductive isolation and the maintenance of species boundaries. Despite their possible ubiquity and importance, the investigation of PEMS has been largely descriptive, lacking any phylogenetic consideration with regard to divergence, and there have been no theoretical or empirical investigations of their evolutionary significance. Here, we (i) clarify PEMS‐related nomenclature; (ii) address the evolutionary origin, maintenance and divergence in PEMS in the context of the protracted life history of sperm and the complex, selective environment of the female reproductive tract; (iii) describe taxonomically widespread types of PEMS: sperm activation, chemotaxis and the dissociation of sperm conjugates; (iv) review the occurence of PEMS throughout the animal kingdom; (v) consider alternative hypotheses for the adaptive value of PEMS; (vi) speculate on the evolutionary implications of PEMS for genomic architecture, sexual selection, and reproductive isolation; and (vii) suggest fruitful directions for future functional and evolutionary analyses of PEMS.

    更新日期:2019-11-18
  • The palaeobiology of belemnites – foundation for the interpretation of rostrum geochemistry
    Biol. Rev. (IF 10.288) Pub Date : 2019-11-15
    René Hoffmann, Kevin Stevens

    Belemnites are an extinct group of Mesozoic coleoid cephalopods with a fossil record ranging from the early Late Triassic [about 240 million years ago (Mya)] to the Cretaceous/Palaeogene boundary (65 Mya). Belemnites were widely distributed, highly abundant and diverse, and an important component of Mesozoic marine food webs. Their internal shells, specifically their low‐Mg calcite rostra, have been used as palaeoenvironmental carbonate archives for the last 70 years. This is primarily due to the assumption that the rostrum calcite formed in equilibrium with the oxygen isotope composition of ambient sea water. Of prime importance for the reliable interpretation of isotope data derived from these biogenic carbonates is a robust reconstruction of the palaeobiology of their producers. Here we provide a critical assessment of published reconstructions of belemnite soft‐body organization and their lifestyle and habitats. Different lines of evidence, including sedimentological, geochemical, morphological, and biomechanical data, point towards an outer shelf habitat of belemnites, for some taxa also including the littoral area. Belemnite habitat temperatures, oxygen content, salinities, and life span are constrained based on observations of the ecology and life history of modern coleoids. Belemnite habitat depth might have been largely controlled by food and temperature, with a temperature optimum between 10°C and 30°C. The distribution of modern coleoids is for most species restricted to well‐oxygenated water masses and a salinity between 27 and 37 psu. The trophic position of belemnites as both predators and prey is documented by unique fossil finds of stomach contents and soft tissue preservation, such as jaws, hooks, and ink sacs. Belemnites were medium‐sized predators in the epipelagic zone (not deeper than ∼200 m) hunting for crustaceans, other cephalopods, and fishes. Taxa with elongated rostra probably were fast and highly manoeuvrable swimmers. Forms with conical rostra represent slow but highly manoeuvrable swimmers, and forms with depressed rostra likely had a bottom‐related life habit. Predators of adult belemnites were sharks, bony fishes, and marine reptiles. Belemnites, like most of the modern coleoids, were relatively short lived, most likely living only for 1–2 years. Understanding the biomineralization of belemnite rostra is highly relevant for an improved interpretation of their geochemistry. Here we confirm that belemnite rostra are composed of low Mg‐calcite fibres, but they do not contain distinct types of laminae. These fibres are composed of two distinct calcite phases. One phase is a filigree network of tetrahedral organic‐rich calcite and the second phase is represented by organic‐poor calcite.

    更新日期:2019-11-15
  • Towards an integrative understanding of soil biodiversity
    Biol. Rev. (IF 10.288) Pub Date : 2019-11-15
    Madhav P. Thakur, Helen R. P. Phillips, Ulrich Brose, Franciska T. De Vries, Patrick Lavelle, Michel Loreau, Jerome Mathieu, Christian Mulder, Wim H. Van der Putten, Matthias C. Rillig, David A. Wardle, Elizabeth M. Bach, Marie L. C. Bartz, Joanne M. Bennett, Maria J. I. Briones, George Brown, Thibaud Decaëns, Nico Eisenhauer, Olga Ferlian, Carlos António Guerra, Birgitta König‐Ries, Alberto Orgiazzi, Kelly S. Ramirez, David J. Russell, Michiel Rutgers, Diana H. Wall, Erin K. Cameron

    Soil is one of the most biodiverse terrestrial habitats. Yet, we lack an integrative conceptual framework for understanding the patterns and mechanisms driving soil biodiversity. One of the underlying reasons for our poor understanding of soil biodiversity patterns relates to whether key biodiversity theories (historically developed for aboveground and aquatic organisms) are applicable to patterns of soil biodiversity. Here, we present a systematic literature review to investigate whether and how key biodiversity theories (species–energy relationship, theory of island biogeography, metacommunity theory, niche theory and neutral theory) can explain observed patterns of soil biodiversity. We then discuss two spatial compartments nested within soil at which biodiversity theories can be applied to acknowledge the scale‐dependent nature of soil biodiversity.

    更新日期:2019-11-15
  • The fossil record of spiders revisited: implications for calibrating trees and evidence for a major faunal turnover since the Mesozoic
    Biol. Rev. (IF 10.288) Pub Date : 2019-11-12
    Ivan L. F. Magalhaes, Guilherme H. F. Azevedo, Peter Michalik, Martín J. Ramírez

    Studies in evolutionary biology and biogeography increasingly rely on the estimation of dated phylogenetic trees using molecular clocks. In turn, the calibration of such clocks is critically dependent on external evidence (i.e. fossils) anchoring the ages of particular nodes to known absolute ages. In recent years, a plethora of new fossil spiders, especially from the Mesozoic, have been described, while the number of studies presenting dated spider phylogenies based on fossil calibrations increased sharply. We critically evaluate 44 of these studies, which collectively employed 67 unique fossils in 180 calibrations. Approximately 54% of these calibrations are problematic, particularly regarding unsupported assignment of fossils to extant clades (44%) and crown (rather than stem) dating (9%). Most of these cases result from an assumed equivalence between taxonomic placement of fossils and their phylogenetic position. To overcome this limitation, we extensively review the literature on fossil spiders, with a special focus on putative synapomorphies and the phylogenetic placement of fossil species with regard to their importance for calibrating higher taxa (families and above) in the spider tree of life. We provide a curated list including 41 key fossils intended to be a basis for future estimations of dated spider phylogenies. In a second step, we use a revised set of 23 calibrations to estimate a new dated spider tree of life based on transcriptomic data. The revised placement of key fossils and the new calibrated tree are used to resolve a long‐standing debate in spider evolution – we tested whether there has been a major turnover in the spider fauna between the Mesozoic and Cenozoic. At least 17 (out of 117) extant families have been recorded from the Cretaceous, implying that at least 41 spider lineages in the family level or above crossed the Cretaeous–Paleogene (K–Pg) boundary. The putative phylogenetic affinities of families known only from the Mesozoic suggest that at least seven Cretaceous families appear to have no close living relatives and might represent extinct lineages. There is no unambiguous fossil evidence of the retrolateral tibial apophysis clade (RTA‐clade) in the Mesozoic, although molecular clock analyses estimated the major lineages within this clade to be at least ∼100 million years old. Our review of the fossil record supports a major turnover showing that the spider faunas in the Mesozoic and the Cenozoic are very distinct at high taxonomic levels, with the Mesozoic dominated by Palpimanoidea and Synspermiata, while the Cenozoic is dominated by Araneoidea and RTA‐clade spiders.

    更新日期:2019-11-13
  • The transportome of the malaria parasite
    Biol. Rev. (IF 10.288) Pub Date : 2019-11-07
    Rowena E. Martin

    Membrane transport proteins, also known as transporters, control the movement of ions, nutrients, metabolites, and waste products across the membranes of a cell and are central to its biology. Proteins of this type also serve as drug targets and are key players in the phenomenon of drug resistance. The malaria parasite has a relatively reduced transportome, with only approximately 2.5% of its genes encoding transporters. Even so, assigning functions and physiological roles to these proteins, and ascertaining their contributions to drug action and drug resistance, has been very challenging. This review presents a detailed critique and synthesis of the disruption phenotypes, protein subcellular localisations, protein functions (observed or predicted), and links to antimalarial drug resistance for each of the parasite's transporter genes. The breadth and depth of the gene disruption data are particularly impressive, with at least one phenotype determined in the parasite's asexual blood stage for each transporter gene, and multiple phenotypes available for 76% of the genes. Analysis of the curated data set revealed there to be relatively little redundancy in the Plasmodium transportome; almost two‐thirds of the parasite's transporter genes are essential or required for normal growth in the asexual blood stage of the parasite, and this proportion increased to 78% when the disruption phenotypes available for the other parasite life stages were included in the analysis. These observations, together with the finding that 22% of the transportome is implicated in the parasite's resistance to existing antimalarials and/or drugs within the development pipeline, indicate that transporters are likely to serve, or are already serving, as drug targets. Integration of the different biological and bioinformatic data sets also enabled the selection of candidates for transport processes known to be essential for parasite survival, but for which the underlying proteins have thus far remained undiscovered. These include potential transporters of pantothenate, isoleucine, or isopentenyl diphosphate, as well as putative anion‐selective channels that may serve as the pore component of the parasite's ‘new permeation pathways’. Other novel insights into the parasite's biology included the identification of transporters for the potential development of antimalarial treatments, transmission‐blocking drugs, prophylactics, and genetically attenuated vaccines. The syntheses presented herein set a foundation for elucidating the functions and physiological roles of key members of the Plasmodium transportome and, ultimately, to explore and realise their potential as therapeutic targets.

    更新日期:2019-11-08
  • Microglia in neuropathology caused by protozoan parasites
    Biol. Rev. (IF 10.288) Pub Date : 2019-11-04
    Katherine Figarella, Hartwig Wolburg, Olga Garaschuk, Michael Duszenko

    Involvement of the central nervous system (CNS) is the most severe consequence of some parasitic infections. Protozoal infections comprise a group of diseases that together affect billions of people worldwide and, according to the World Health Organization, are responsible for more than 500000 deaths annually. They include African and American trypanosomiasis, leishmaniasis, malaria, toxoplasmosis, and amoebiasis. Mechanisms underlying invasion of the brain parenchyma by protozoa are not well understood and may depend on parasite nature: a vascular invasion route is most common. Immunosuppression favors parasite invasion into the CNS and therefore the host immune response plays a pivotal role in the development of a neuropathology in these infectious diseases. In the brain, microglia are the resident immune cells active in defense against pathogens that target the CNS. Beside their direct role in innate immunity, they also play a principal role in coordinating the trafficking and recruitment of other immune cells from the periphery to the CNS. Despite their evident involvement in the neuropathology of protozoan infections, little attention has given to microglia–parasite interactions. This review describes the most prominent features of microglial cells and protozoan parasites and summarizes the most recent information regarding the reaction of microglial cells to parasitic infections. We highlight the involvement of the periphery–brain axis and emphasize possible scenarios for microglia–parasite interactions.

    更新日期:2019-11-04
  • The genetic script of metastasis
    Biol. Rev. (IF 10.288) Pub Date : 2019-10-30
    Goodwin G. Jinesh, Andrew S. Brohl

    Metastasis is a pivotal event that changes the course of cancers from benign and treatable to malignant and difficult to treat, resulting in the demise of patients. Understanding the genetic control of metastasis is thus crucial to develop efficient and sustainable targeted therapies. Here we discuss the alterations in epigenetic mechanisms, transcription, chromosomal instability, chromosome imprinting, non‐coding RNAs, coding RNAs, mutant RNAs, enhancers, G‐quadruplexes, and copy number variation to dissect the genetic control of metastasis. We conclude that the genetic control of metastasis is predominantly executed through epithelial to mesenchymal transition and evasion of cell death. We discuss how genetic regulatory mechanisms can be harnessed for therapeutic purposes to achieve sustainable control over cancer metastasis.

    更新日期:2019-10-30
  • Natural selection in mimicry
    Biol. Rev. (IF 10.288) Pub Date : 2019-10-30
    Bruce Anderson, Marinus L. de Jager

    Biological mimicry has served as a salient example of natural selection for over a century, providing us with a dazzling array of very different examples across many unrelated taxa. We provide a conceptual framework that brings together apparently disparate examples of mimicry in a single model for the purpose of comparing how natural selection affects models, mimics and signal receivers across different interactions. We first analyse how model–mimic resemblance likely affects the fitness of models, mimics and receivers across diverse examples. These include classic Batesian and Müllerian butterfly systems, nectarless orchids that mimic Hymenoptera or nectar‐producing plants, caterpillars that mimic inert objects unlikely to be perceived as food, plants that mimic abiotic objects like carrion or dung and aggressive mimicry where predators mimic food items of their own prey. From this, we construct a conceptual framework of the selective forces that form the basis of all mimetic interactions. These interactions between models, mimics and receivers may follow four possible evolutionary pathways in terms of the direction of selection resulting from model–mimic resemblance. Two of these pathways correspond to the selective pressures associated with what is widely regarded as Batesian and Müllerian mimicry. The other two pathways suggest mimetic interactions underpinned by distinct selective pressures that have largely remained unrecognized. Each pathway is characterized by theoretical differences in how model–mimic resemblance influences the direction of selection acting on mimics, models and signal receivers, and the potential for consequent (co)evolutionary relationships between these three protagonists. The final part of this review describes how selective forces generated through model–mimic resemblance can be opposed by the basic ecology of interacting organisms and how those forces may affect the symmetry, strength and likelihood of (co)evolution between the three protagonists within the confines of the four broad evolutionary possibilities. We provide a clear and pragmatic visualization of selection pressures that portrays how different mimicry types may evolve. This conceptual framework provides clarity on how different selective forces acting on mimics, models and receivers are likely to interact and ultimately shape the evolutionary pathways taken by mimetic interactions, as well as the constraints inherent within these interactions.

    更新日期:2019-10-30
  • The Handicap Principle: how an erroneous hypothesis became a scientific principle
    Biol. Rev. (IF 10.288) Pub Date : 2019-10-23
    Dustin J. Penn, Szabolcs Számadó

    The most widely cited explanation for the evolution of reliable signals is Zahavi's so‐called Handicap Principle, which proposes that signals are honest because they are costly to produce. Here we provide a critical review of the Handicap Principle and its theoretical development. We explain why this idea is erroneous, and how it nevertheless became widely accepted as the leading explanation for honest signalling. In 1975, Zahavi proposed that elaborate secondary sexual characters impose ‘handicaps’ on male survival, not due to inadvertent signalling trade‐offs, but as a mechanism that functions to demonstrate males' genetic quality to potential mates. His handicap hypothesis received many criticisms, and in response, Zahavi clarified his hypothesis and explained that it assumes that signals are wasteful as well as costly, and that they evolve because wastefulness enforces honesty. He proposed that signals evolve under ‘signal selection’, a non‐Darwinian type of selection that favours waste rather than efficiency. He maintained that the handicap hypothesis provides a general principle to explain the evolution of all types of signalling systems, i.e. the Handicap Principle. In 1977, Zahavi proposed a second hypothesis for honest signalling, which received many different labels and interpretations, although it was assumed to be another example of handicap signalling. In 1990, Grafen published models that he claimed vindicated Zahavi's Handicap Principle. His conclusions were widely accepted and the Handicap Principle subsequently became the dominant paradigm for explaining the evolution of honest signalling in the biological and social sciences. Researchers have subsequently focused on testing predications of the Handicap Principle, such as measuring the absolute costs of honest signals (and using energetic and other proximate costs as proxies for fitness), but very few have attempted to test Grafen's models. We show that Grafen's models do not support the handicap hypothesis, although they do support Zahavi's second hypothesis, which proposes that males adjust their investment into the expression of their sexual signals according to their condition and ability to bear the costs (and risks to their survival). Rather than being wasteful over‐investments, honest signals evolve in this scenario because selection favours efficient and optimal investment into signal expression and minimizes signalling costs. This idea is very different from the handicap hypothesis, but it has been widely misinterpreted and equated to the Handicap Principle. Theoretical studies have since shown that signalling costs paid at the equilibrium are neither sufficient nor necessary to maintain signal honesty, and that honesty can evolve through differential benefits, as well as differential costs. There have been increasing criticisms of the Handicap Principle, but they have focused on the limitations of Grafen's model and overlooked the fact that it is not a handicap model. This model is better understood within a Darwinian framework of adaptive signalling trade‐offs, without the added burden and confusing logic of the Handicap Principle. There is no theoretical or empirical support for the Handicap Principle and the time is long overdue to usher this idea into an ‘honorable retirement’.

    更新日期:2019-10-24
  • Effects of plant diversity on soil carbon in diverse ecosystems: a global meta‐analysis
    Biol. Rev. (IF 10.288) Pub Date : 2019-10-18
    Xinli Chen, Han Y. H. Chen, Chen Chen, Zilong Ma, Eric B. Searle, Zaipeng Yu, Zhiqun Huang

    Soil organic carbon (SOC) is a valuable resource for mediating global climate change and securing food production. Despite an alarming rate of global plant diversity loss, uncertainties concerning the effects of plant diversity on SOC remain, because plant diversity not only stimulates litter inputs via increased productivity, thus enhancing SOC, but also stimulates microbial respiration, thus reducing SOC. By analysing 1001 paired observations of plant mixtures and corresponding monocultures from 121 publications, we show that both SOC content and stock are on average 5 and 8% higher in species mixtures than in monocultures. These positive mixture effects increase over time and are more pronounced in deeper soils. Microbial biomass carbon, an indicator of SOC release and formation, also increases, but the proportion of microbial biomass carbon in SOC is lower in mixtures. Moreover, these species‐mixture effects are consistent across forest, grassland, and cropland systems and are independent of background climates. Our results indicate that converting 50% of global forests from mixtures to monocultures would release an average of 2.70 Pg C from soil annually over a period of 20 years: about 30% of global annual fossil‐fuel emissions. Our study highlights the importance of plant diversity preservation for the maintenance of soil carbon sequestration in discussions of global climate change policy.

    更新日期:2019-10-19
  • New insight into sortilin in controlling lipid metabolism and the risk of atherogenesis
    Biol. Rev. (IF 10.288) Pub Date : 2019-10-18
    Xin Su, Daoquan Peng

    Dyslipidemia, including increased plasma levels of low‐density lipoprotein cholesterol (LDL‐C), very low‐density lipoprotein cholesterol and triglyceride, and decreased plasma levels of high‐density lipoprotein cholesterol, has been considered a key factor associated with a series of health problems grouped together as metabolic syndrome. Worldwide, dyslipidemia has become a pressing issue, together with the rising prevalence of metabolic syndrome and cardiovascular disease (CVD). Recently, multiple genome‐wide association studies and experimental analyses have been used to assess the underlying genetic basis of lipid metabolism and to identify novel gene loci that contribute to the alterations in lipid levels. The results have demonstrated that sortilin, which is encoded by SORT1, plays an important role in modulating the level of LDL‐C and the risk of CVD. Herein, we summarize the current understanding of the role of sortilin in the pathogenesis of dyslipidemia and atherosclerosis. Furthermore, we provide new insights into the potential mechanisms by which sortilin affects lipid metabolism in hepatocytes, adipocytes, and macrophages.

    更新日期:2019-10-19
  • Communicative roots of complex sociality and cognition
    Biol. Rev. (IF 10.288) Pub Date : 2019-10-14
    Anna I. Roberts, Sam G. B. Roberts

    Mammals living in more complex social groups typically have large brains for their body size and many researchers have proposed that the primary driver of the increase in brain size through primate and hominin evolution was the selection pressures associated with sociality. Many mammals, and especially primates, use flexible signals that show a high degree of voluntary control and these signals may play an important role in forming and maintaining social relationships between group members. However, the specific role that cognitive skills play in this complex communication, and how in turn this relates to sociality, is still unclear. The hypothesis for the communicative roots of complex sociality and cognition posits that cognitive demands behind the communication needed to form and maintain bonded social relationships in complex social settings drives the link between brain size and sociality. We review the evidence in support of this hypothesis and why key features of cognitively complex communication such as intentionality and referentiality should be more effective in forming and maintaining bonded relationships as compared with less cognitively complex communication. Exploring the link between cognition, communication and sociality provides insights into how increasing flexibility in communication can facilitate the emergence of social systems characterised by bonded social relationships, such as those found in non‐human primates and humans. To move the field forward and carry out both within‐ and among‐species comparisons, we advocate the use of social network analysis, which provides a novel way to describe and compare social structure. Using this approach can lead to a new, systematic way of examining social and communicative complexity across species, something that is lacking in current comparative studies of social structure.

    更新日期:2019-10-14
  • Patterns and variation in the mammal parasite–glucorticoid relationship
    Biol. Rev. (IF 10.288) Pub Date : 2019-10-13
    Charlotte Defolie, Thomas Merkling, Claudia Fichtel

    Parasites are ubiquitous and can strongly affect their hosts through mechanisms such as behavioural changes, increased energetic costs and/or immunomodulation. When parasites are detrimental to their hosts, they should act as physiological stressors and elicit the release of glucocorticoids. Alternatively, previously elevated glucocorticoid levels could facilitate parasite infection due to neuroimmunomodulation. However, results are equivocal, with studies showing either positive, negative or no relationship between parasite infection and glucocorticoid levels. Since factors such as parasite type, infection severity or host age and sex can influence the parasite–glucocorticoid relationship, we review the main mechanisms driving this relationship. We then perform a phylogenetic meta‐analysis of 110 records from 65 studies in mammalian hosts from experimental and observational studies to quantify the general direction of this relationship and to identify ecological and methodological drivers of the observed variability. Our review produced equivocal results concerning the direction of the relationship, but there was stronger support for a positive relationship, although causality remained unclear. Mechanisms such as host manipulation for parasite survival, host response to infection, cumulative effects of multiple stressors, and neuro‐immunomodulatory effects of glucocorticoids could explain the positive relationship. Our meta‐analysis results revealed an overall positive relationship between glucocorticoids and parasitism among both experimental and observational studies. Because all experimental studies included were parasite manipulations, we conclude that parasites caused in general an increase in glucocorticoid levels. To obtain a better understanding of the directionality of this link, experimental manipulation of glucocorticoid levels is now required to assess the causal effects of high glucocorticoid levels on parasite infection. Neither parasite type, the method used to assess parasite infection nor phylogeny influenced the relationship, and there was no evidence for publication bias. Future studies should attempt to be as comprehensive as possible, including moderators potentially influencing the parasite–glucocorticoid relationship. We particularly emphasise the importance of testing hosts of a broad age range, concomitantly measuring sex hormone levels or at least reproductive status, and for observational studies, also considering food availability, host body condition and social stressors to obtain a better understanding of the parasite–glucocorticoid relationship.

    更新日期:2019-10-14
  • Frugivory and seed dispersal by chelonians: a review and synthesis
    Biol. Rev. (IF 10.288) Pub Date : 2019-10-13
    Wilfredo Falcón, Don Moll, Dennis M. Hansen

    In recent years, it has become clear that frugivory and seed dispersal (FSD) by turtles and tortoises is much more common than previously thought. We here review published and unpublished records of chelonian FSD, and assess the role of chelonians as seed dispersers, from individual species to the community level. We first discuss the distribution of chelonian FSD and the characteristics of the fruit and/or seed species eaten and dispersed by chelonians. We then use the seed dispersal efficiency framework to explore the quantitative and qualitative components of seed dispersal by tortoises and turtles, embarking on a journey from when the fruits and/or seeds are consumed, to when and where they are deposited, and assess how efficient chelonians are as seed dispersers. We finally discuss chelonian FSD in the context of communities and of chelonians as megafauna. A substantial proportion of the world's aquatic and terrestrial turtles and a major part of testudinid tortoises (71 species in 12 families) include fruits and/or seeds in their diet; fruits of at least 588 plant species in 121 families are ingested and/or dispersed by chelonians. For some chelonians, overall or in certain seasons, fruit may even form the largest part of their diet. Contrary to seed dispersal by lizards, the other major reptilian frugivores, chelonian FSD is not an island phenomenon in terms of geographic distribution. Nevertheless, on islands tortoises are often among the largest native terrestrial vertebrates – or were until humans arrived. We synthesise our knowledge of chelonian FSD, and discuss the relevance of our findings for conservation and restoration, especially in relation to rewilding with large and giant tortoises.

    更新日期:2019-10-14
  • The deforestation of Easter Island
    Biol. Rev. (IF 10.288) Pub Date : 2019-10-10
    Valentí Rull

    Easter Island deforestation has traditionally been viewed as an abrupt island‐wide event caused by the prehistoric Rapanui civilization, which precipitated its own cultural collapse. This view emerges from early palaeoecological analyses of lake sediments, which showed a sudden and total replacement of palm pollen by grass pollen shortly after Polynesian settlement (800–1200 CE). However, further palaeoecological research has challenged this view, showing that the apparent abruptness and island‐wide synchronicity of forest removal was an artefact due to the occurrence of a sedimentary gap of several millennia that prevented a detailed record of the replacement of palm‐dominated forests by grass meadows. During the last decade, several continuous (gap‐free) and chronologically coherent sediment cores encompassing the last millennia have been retrieved and analysed, providing a new picture of forest removal on Easter Island. According to these analyses, deforestation was not abrupt but gradual and occurred at different times and rates, depending on the site. Regarding the causes, humans were not the only factors responsible for forest clearing, as climatic droughts as well as climate–human–landscape feedbacks and synergies also played a role. In summary, the deforestation of Easter Island was a complex process that was spatially and temporally heterogeneous and took place under the actions and interactions of both natural and anthropogenic drivers. In addition, archaeological evidence shows that the Rapanui civilization was resilient to deforestation and remained healthy until European contact, which contradicts the occurrence of a cultural collapse. Further research should aim to obtain new continuous cores and make use of recently developed biomarker analyses to advance towards a holistic view of the patterns, causes and consequences of Easter Island deforestation.

    更新日期:2019-10-10
  • An ecological framework of neophobia: from cells to organisms to populations
    Biol. Rev. (IF 10.288) Pub Date : 2019-10-10
    Adam L. Crane, Grant E. Brown, Douglas P. Chivers, Maud C. O. Ferrari

    Neophobia is the fear of novel stimuli or situations. This phenotype has recently received much ecological attention, primarily in the context of decision making. Here, we explore neophobia across biological levels of organisation, first describing types of neophobia among animals and the underlying causes of neophobia, highlighting high levels of risk and uncertainty as key drivers. We place neophobia in the framework of Error Management Theory and Signal Detection Theory, showing how increases in overall risk and uncertainty can lead to costly non‐responses towards novel threats unless individuals lower their response threshold and become neophobic. We then discuss how neophobic behaviour translates into population and evolutionary consequences before introducing neophobia‐like processes at the cellular level, where some phenomena such as allergy and autoimmunity can parallel neophobic behaviour. Finally, we discuss neophobia attenuation, considering how a sudden change in the environment from dangerous to safe can lead to problematic over‐responses (i.e. the ‘maladaptive defensive carry‐over’ hypothesis), and discuss treatment methods for such over‐responses. We anticipate that bridging the concept of neophobia with a process‐centered perspective can facilitate a transfer of insight across organisational levels.

    更新日期:2019-10-10
  • Recent advances in amniote palaeocolour reconstruction and a framework for future research
    Biol. Rev. (IF 10.288) Pub Date : 2019-09-19
    Arindam Roy, Michael Pittman, Evan T. Saitta, Thomas G. Kaye, Xing Xu

    Preserved melanin pigments have been discovered in fossilised integumentary appendages of several amniote lineages (fishes, frogs, snakes, marine reptiles, non‐avialan dinosaurs, birds, and mammals) excavated from lagerstätten across the globe. Melanisation is a leading factor in organic integument preservation in these fossils. Melanin in extant vertebrates is typically stored in rod‐ to sphere‐shaped, lysosome‐derived, membrane‐bound vesicles called melanosomes. Black, dark brown, and grey colours are produced by eumelanin, and reddish‐brown colours are produced by phaeomelanin. Specific morphotypes and nanostructural arrangements of melanosomes and their relation to the keratin matrix in integumentary appendages create the so‐called 'structural colours'. Reconstruction of colour patterns in ancient animals has opened an exciting new avenue for studying their life, behaviour and ecology. Modern relationships between the shape, arrangement, and size of avian melanosomes, melanin chemistry, and feather colour have been applied to reconstruct the hues and colour patterns of isolated feathers and plumages of the dinosaurs Anchiornis, Sinosauropteryx, and Microraptor in seminal papers that initiated the field of palaeocolour reconstruction. Since then, further research has identified countershading camouflage patterns, and informed subsequent predictions on the ecology and behaviour of these extinct animals. However, palaeocolour reconstruction remains a nascent field, and current approaches have considerable potential for further refinement, standardisation, and expansion. This includes detailed study of non‐melanic pigments that might be preserved in fossilised integuments. A common issue among existing palaeocolour studies is the lack of contextualisation of different lines of evidence and the wide variety of techniques currently employed. To that end, this review focused on fossil amniotes: (i) produces an overarching framework that appropriately reconstructs palaeocolour by accounting for the chemical signatures of various pigments, morphology and local arrangement of pigment‐bearing vesicles, pigment concentration, macroscopic colour patterns, and taphonomy; (ii) provides background context for the evolution of colour‐producing mechanisms; and (iii) encourages future efforts in palaeocolour reconstructions particularly of less‐studied groups such as non‐dinosaur archosaurs and non‐archosaur amniotes.

    更新日期:2019-09-21
  • Ecosystem services provided by armadillos
    Biol. Rev. (IF 10.288) Pub Date : 2019-08-25
    Thiago F. Rodrigues, Aline M. B. Mantellatto, Mariella Superina, Adriano G. Chiarello

    Awareness of the natural ecological processes provided by organisms that benefit human well‐being has significantly progressed towards the goal of making conservation a mainstream value. Identifying different services and the species that provide them is a vital first step for the management and maintenance of these so‐called ecosystem services. Herein, we specifically address the armadillos, which play key functional roles in terrestrial ecosystems, including as ecosystem engineers, predators, and vectors of invertebrates and nutrients, although these roles have often been overlooked. Armadillos can control pests, disperse seeds, and be effective sentinels of potential disease outbreaks or bioindicators of environmental contaminants. They also supply important material (meat, medicines) and non‐material (learning, inspiration) contributions all over the Americas. We identify key gaps in the understanding of ecosystem services provided by armadillos and areas for future research required to clarify their functional role in terrestrial ecosystems and the services they supply. Such information will produce powerful arguments for armadillo conservation.

    更新日期:2019-08-26
  • Human protein paucimannosylation: cues from the eukaryotic kingdoms
    Biol. Rev. (IF 10.288) Pub Date : 2019-08-14
    Harry C. Tjondro, Ian Loke, Sayantani Chatterjee, Morten Thaysen‐Andersen

    Paucimannosidic proteins (PMPs) are bioactive glycoproteins carrying truncated α‐ or β‐mannosyl‐terminating asparagine (N)‐linked glycans widely reported across the eukaryotic domain. Our understanding of human PMPs remains limited, despite findings documenting their existence and association with human disease glycobiology. This review comprehensively surveys the structures, biosynthetic routes and functions of PMPs across the eukaryotic kingdoms with the aim of synthesising an improved understanding on the role of protein paucimannosylation in human health and diseases. Convincing biochemical, glycoanalytical and biological data detail a vast structural heterogeneity and fascinating tissue‐ and subcellular‐specific expression of PMPs within invertebrates and plants, often comprising multi‐α1,3/6‐fucosylation and β1,2‐xylosylation amongst other glycan modifications and non‐glycan substitutions e.g. O‐methylation. Vertebrates and protists express less‐heterogeneous PMPs typically only comprising variable core fucosylation of bi‐ and trimannosylchitobiose core glycans. In particular, the Manα1,6Manβ1,4GlcNAc(α1,6Fuc)β1,4GlcNAcβAsn glycan (M2F) decorates various human neutrophil proteins reportedly displaying bioactivity and structural integrity demonstrating that they are not degradation products. Less‐truncated paucimannosidic glycans (e.g. M3F) are characteristic glycosylation features of proteins expressed by human cancer and stem cells. Concertedly, these observations suggest the involvement of human PMPs in processes related to innate immunity, tumorigenesis and cellular differentiation. The absence of human PMPs in diverse bodily fluids studied under many (patho)physiological conditions suggests extravascular residence and points to localised functions of PMPs in peripheral tissues. Absence of PMPs in Fungi indicates that paucimannosylation is common, but not universally conserved, in eukaryotes. Relative to human PMPs, the expression of PMPs in plants, invertebrates and protists is more tissue‐wide and constitutive yet, similar to their human counterparts, PMP expression remains regulated by the physiology of the producing organism and PMPs evidently serve essential functions in development, cell–cell communication and host–pathogen/symbiont interactions. In most PMP‐producing organisms, including humans, the N‐acetyl‐β‐hexosaminidase isoenzymes and linkage‐specific α‐mannosidases are glycoside hydrolases critical for generating PMPs via N‐acetylglucosaminyltransferase I (GnT‐I)‐dependent and GnT‐I‐independent truncation pathways. However, the identity and structure of many species‐specific PMPs in eukaryotes, their biosynthetic routes, strong tissue‐ and development‐specific expression, and diverse functions are still elusive. Deep exploration of these PMP features involving, for example, the characterisation of endogenous PMP‐recognising lectins across a variety of healthy and N‐acetyl‐β‐hexosaminidase‐deficient human tissue types and identification of microbial adhesins reactive to human PMPs, are amongst the many tasks required for enhanced insight into the glycobiology of human PMPs. In conclusion, the literature supports the notion that PMPs are significant, yet still heavily under‐studied biomolecules in human glycobiology that serve essential functions and create structural heterogeneity not dissimilar to other human N‐glycoprotein types. Human PMPs should therefore be recognised as bioactive glycoproteins that are distinctly different from the canonical N‐glycoprotein classes and which warrant a more dedicated focus in glycobiological research.

    更新日期:2019-08-14
  • Quantifying the contribution of immigration to population dynamics: a review of methods, evidence and perspectives in birds and mammals
    Biol. Rev. (IF 10.288) Pub Date : 2019-08-05
    Alexandre Millon, Xavier Lambin, Sébastien Devillard, Michael Schaub

    The demography of a population is often reduced to the apparent (or local) survival of individuals and their realised fecundity within a study area defined according to logistical constraints rather than landscape features. Such demographics are then used to infer whether a local population contributes positively to population dynamics across a wider landscape context. Such a simplistic approach ignores a fundamental process underpinning population dynamics: dispersal. Indeed, it has long been accepted that immigration contributed by dispersers that emigrated from neighbouring populations may strongly influence the net growth of a local population. To date however, we lack a clear picture of how widely immigration rate varies both among and within populations, in relation to extrinsic and intrinsic ecological conditions, even for the best‐studied avian and mammalian populations. This empirical knowledge gap precludes the emergence of a sound conceptual framework that ought to inform conservation and population ecology. This review, conducted on both birds and mammals, has thus three complementary objectives. First, we describe and evaluate the relative merits of methods used to quantify immigration and how they relate to widely applicable metrics. We identify two simple and unifying metrics to measure immigration: the immigration rate it defined as the ratio of the number of immigrants present in the population at time t + 1 and the total breeding population in year t, and πt, the proportion of immigrants among new recruits (i.e. new breeders). Two recently developed methods are likely to provide the most valuable data on immigration in the near future: individual parentage (rather than population) assignments based on genetic sampling, and spatially explicit integrated population models combining multiple sources of demographic data (survival, fecundity and population counts). Second, we report on a systematic literature review of studies providing a quantitative measure of immigration. Although the diversity of methods employed precludes detailed analyses, it appears that the number of immigrants exceeds locally born individuals in recruitment for most avian populations (median πt = 0.57, N = 45 estimates from 37 studies), a figure twofold higher than estimated for mammalian populations (median πt = 0.26, N = 33 estimates from 11 studies). Third, recent quantitative studies reveal that immigration can be the main driver of temporal variation in population growth rates, across a wide array of demographic and spatial contexts. To what extent immigration acts as a regulatory process has however been considered only rarely to date and deserves more attention. Overall, it is likely that most populations benefit from immigrants without necessarily being sink populations. Furthermore, we suggest that quantitative estimates of immigration should be core to future demographic studies and plead for more empirical evidence about the ways in which immigration interacts with local demographic processes to shape population dynamics. Finally, we discuss how to tackle spatial population dynamics by exploring, beyond the classical source–sink framework, the extent to which populations exchange individuals according to spatial scale and type of population distribution throughout the landscape.

    更新日期:2019-08-06
  • Sesamoids in tetrapods: the origin of new skeletal morphologies
    Biol. Rev. (IF 10.288) Pub Date : 2019-07-29
    Virginia Abdala, Miriam C. Vera, Lucila I. Amador, Gabriela Fontanarrosa, Jessica Fratani, María L. Ponssa

    Along with supernumerary bones, sesamoids, defined as any organized intratendinous/intraligamentous structure, including those composed of fibrocartilage, adjacent to an articulation or joint, have been frequently considered as enigmatic structures associated with the joints of the skeletal system of vertebrates. This review allows us to propose a dynamic model to account for part of skeletal phenotypic diversity: during evolution, sesamoids can become displaced, attaching to and detaching from the long bone epiphyses and diaphysis. Epiphyses, apophyses and detached sesamoids are able to transform into each other, contributing to the phenotypic variability of the tetrapod skeleton. This dynamic model is a new paradigm to delineate the contribution of sesamoids to skeletal diversity. Herein, we first present a historical approach to the study of sesamoids, discussing the genetic versus epigenetic theories of their genesis and growth. Second, we construct a dynamic model. Third, we present a summary of literature on sesamoids of the main groups of tetrapods, including veterinary and human clinical contributions, which are the best‐studied aspects of sesamoids in recent decades. Finally, we discuss the identity of certain structures that have been labelled as sesamoids despite insufficient formal testing of homology. We also propose a new definition to help the identification of sesamoids in general. This review is particularly timely, given the recent increasing interest and research activity into the developmental biology and mechanics of sesamoids. With this updated and integrative discussion, we hope to pave the way to improve the understanding of sesamoid biology and evolution.

    更新日期:2019-07-30
  • The time frame of home‐range studies: from function to utilization
    Biol. Rev. (IF 10.288) Pub Date : 2019-07-25
    Guillaume Péron

    As technological and statistical innovations open new avenues in movement ecology, I review the fundamental implications of the time frame of home‐range studies, with the aim of associating terminologies consistently with research objectives and methodologies. There is a fundamental distinction between (a) extrapolations of stationary distributions, associated with long time scales and aiming at asymptotic consistency, and (b) period‐specific techniques, aiming at specificity but typically sensitive to the sampling design. I then review the difference between function and utilization in home‐range studies. Most home‐range studies are based on phenomenological descriptions of the time budgets of the study animals, not the function of the visited areas. I highlight emerging trends in automated pattern‐recognition techniques for inference about function rather than utilization.

    更新日期:2019-07-26
  • Mechanisms of the Ase1/PRC1/MAP65 family in central spindle assembly
    Biol. Rev. (IF 10.288) Pub Date : 2019-07-25
    Zhen‐Yu She, Ya‐Lan Wei, Yang Lin, Yue‐Ling Li, Ming‐Hui Lu

    During cytokinesis, the organization of the spindle midzone and chromosome segregation is controlled by the central spindle, a microtubule cytoskeleton containing kinesin motors and non‐motor microtubule‐associated proteins. The anaphase spindle elongation 1/protein regulator of cytokinesis 1/microtubule associated protein 65 (Ase1/PRC1/MAP65) family of microtubule‐bundling proteins are key regulators of central spindle assembly, mediating microtubule crosslinking and spindle elongation in the midzone. Ase1/PRC1/MAP65 serves as a complex regulatory platform for the recruitment of other midzone proteins at the spindle midzone. Herein, we summarize recent advances in understanding of the structural domains and molecular kinetics of the Ase1/PRC1/MAP65 family. We summarize the regulatory network involved in post‐translational modifications of Ase1/PRC1 by cyclin‐dependent kinase 1 (Cdk1), cell division cycle 14 (Cdc14) and Polo‐like kinase 1 (Plk1) and also highlight multiple functions of Ase1/PRC1 in central spindle organization, spindle elongation and cytokinesis during cell division.

    更新日期:2019-07-25
  • Beyond trophic morphology: stable isotopes reveal ubiquitous versatility in marine turtle trophic ecology
    Biol. Rev. (IF 10.288) Pub Date : 2019-07-24
    Christine Figgener, Joseph Bernardo, Pamela T. Plotkin

    The idea that interspecific variation in trophic morphology among closely related species effectively permits resource partitioning has driven research on ecological radiation since Darwin first described variation in beak morphology among Geospiza.

    更新日期:2019-07-24
  • Fire as a key driver of Earth's biodiversity
    Biol. Rev. (IF 10.288) Pub Date : 2019-07-12
    Tianhua He, Byron B. Lamont, Juli G. Pausas

    Many terrestrial ecosystems are fire prone, such that their composition and structure are largely due to their fire regime. Regions subject to regular fire have exceptionally high levels of species richness and endemism, and fire has been proposed as a major driver of their diversity, within the context of climate, resource availability and environmental heterogeneity. However, current fire‐management practices rarely take into account the ecological and evolutionary roles of fire in maintaining biodiversity. Here, we focus on the mechanisms that enable fire to act as a major ecological and evolutionary force that promotes and maintains biodiversity over numerous spatiotemporal scales. From an ecological perspective, the vegetation, topography and local weather conditions during a fire generate a landscape with spatial and temporal variation in fire‐related patches (pyrodiversity), and these produce the biotic and environmental heterogeneity that drives biodiversity across local and regional scales. There have been few empirical tests of the proposition that ‘pyrodiversity begets biodiversity’ but we show that biodiversity should peak at moderately high levels of pyrodiversity. Overall species richness is greatest immediately after fire and declines monotonically over time, with postfire successional pathways dictated by animal habitat preferences and varying lifespans among resident plants. Theory and data support the ‘intermediate disturbance hypothesis’ when mean patch species diversity is correlated with mean fire intervals. Postfire persistence, recruitment and immigration allow species with different life histories to coexist. From an evolutionary perspective, fire drives population turnover and diversification by promoting a wide range of adaptive responses to particular fire regimes. Among 39 comparisons, the number of species in 26 fire‐prone lineages is much higher than that in their non‐fire‐prone sister lineages. Fire and its byproducts may have direct mutagenic effects, producing novel genotypes that can lead to trait innovation and even speciation. A paradigm shift aimed at restoring biodiversity‐maintaining fire regimes across broad landscapes is required among the fire research and management communities. This will require ecologists and other professionals to spread the burgeoning fire‐science knowledge beyond scientific publications to the broader public, politicians and media.

    更新日期:2019-07-12
  • On how risk and group size interact to influence vigilance
    Biol. Rev. (IF 10.288) Pub Date : 2019-07-03
    Guy Beauchamp

    Vigilance allows animals to monitor their surroundings for signs of danger associated with predators or rivals. As vigilance is costly, models predict that it should increase when the risk posed by predators or rivals increases. In addition, vigilance is expected to decrease in larger groups that provide more safety against predators. Risk and group size are thus two key determinants of vigilance. Together, they could have additive or interactive effects. If risk and group size interacted, the magnitude of the group‐size effect on vigilance would vary depending on the level of risk experienced, implying that the benefits of sociality in terms of vigilance vary with risk. Depending on the model, vigilance is predicted to decrease more rapidly with group size at low risk or at high risk. Little work has focused directly on the interaction between risk and group size, making it difficult to understand under which conditions particular interactive effects arise and whether interactive effects are common in natural systems. I review the vast literature on vigilance in birds and mammals to assess whether interactive effects between risk and group size are common, and if present, which pattern occurs more frequently. In studies involving predation risk, the greatest proportion reported no statistically significant interactive effects. In other cases, vigilance decreased with group size more rapidly at low or high risk in a similar proportion of studies. In studies involving risk posed by rivals (social risk), most documented a more rapid decrease in vigilance with group size at low than at high risk, as predicted if the need to monitor rivals increases in larger groups. Low statistical power to detect interactive effects might have been an issue in several studies. The absence of interactive effects, on the other hand, might suggest constraints or limits on the ability of animals to adjust vigilance to current risk or group sizes. Interactive effects on vigilance have implications for the evolution of sociality and for our understanding of the phenotypic plasticity of predator‐ and competitor‐induced defences and deserve more attention in future studies.

    更新日期:2019-07-04
  • Mycorrhizal types differ in ecophysiology and alter plant nutrition and soil processes
    Biol. Rev. (IF 10.288) Pub Date : 2019-07-03
    Leho Tedersoo, Mohammad Bahram

    Mycorrhizal fungi benefit plants by improved mineral nutrition and protection against stress, yet information about fundamental differences among mycorrhizal types in fungi and trees and their relative importance in biogeochemical processes is only beginning to accumulate. We critically review and synthesize the ecophysiological differences in ectomycorrhizal, ericoid mycorrhizal and arbuscular mycorrhizal symbioses and the effect of these mycorrhizal types on soil processes from local to global scales. We demonstrate that guilds of mycorrhizal fungi display substantial differences in genome‐encoded capacity for mineral nutrition, particularly acquisition of nitrogen and phosphorus from organic material. Mycorrhizal associations alter the trade‐off between allocation to roots or mycelium, ecophysiological traits such as root exudation, weathering, enzyme production, plant protection, and community assembly as well as response to climate change. Mycorrhizal types exhibit differential effects on ecosystem carbon and nutrient cycling that affect global elemental fluxes and may mediate biome shifts in response to global change. We also note that most studies performed to date have not been properly replicated and collectively suffer from strong geographical sampling bias towards temperate biomes. We advocate that combining carefully replicated field experiments and controlled laboratory experiments with isotope labelling and ‐omics techniques offers great promise towards understanding differences in ecophysiology and ecosystem services among mycorrhizal types.

    更新日期:2019-07-04
  • The vascular protective role of oestradiol: a focus on postmenopausal oestradiol deficiency and aneurysmal subarachnoid haemorrhage
    Biol. Rev. (IF 10.288) Pub Date : 2019-07-01
    Shruthi S. Ramesh, Rita Christopher, Bhagavatula Indira Devi, Dhananjaya I. Bhat

    The steroid hormone, oestradiol, has pleiotropic functions. The protective effects of oestradiol are attributed to its anti‐inflammatory, antioxidant, anti‐atherogenic, anti‐apoptotic, vasodilatory activities and regulation of micro RNA. Oestradiol upregulates endothelial nitric oxide synthase gene expression and increases the production of nitric oxide, an important vasodilator. It suppresses the renin–angiotensin system and monitors haemodynamic stress. The hormone maintains the integrity of blood vessels by reducing oxidative stress while upregulating the expression of antioxidant enzymes and prevents vascular inflammation by regulating pro‐ and anti‐inflammatory cytokines. Aneurysmal subarachnoid haemorrhage (aSAH) occurring as a consequence of the rupture of an intracranial aneurysm is a devastating cerebrovascular event, representing 5–7% of all strokes. Postmenopausal women are more susceptible to aSAH compared to men in the same age group. This gender disparity has been attributed to reduced levels of the vascular protective hormone oestradiol following menopause. This review is focused on the protective role of oestradiol on vasculature and how the drop in oestradiol levels after menopause dramatically increases the incidence of aSAH in women. During menopause, oestradiol deficiency may affect vascular integrity causing dysregulation of vascular homeostasis by affecting the renin–angiotensin–aldosterone system (RAAS) and inflammatory and apoptotic cascades, resulting in the weakening of the cerebral arterial wall and potentially to development of an aneurysm and its rupture. In view of the role of oestradiol in maintaining vascular integrity, treatments involving hormone replacement could be a promising approach in postmenopausal women who are at risk of developing or rupturing an intracranial aneurysm.

    更新日期:2019-07-02
  • Can't see the colony for the bees: behavioural perspectives of biological individuality
    Biol. Rev. (IF 10.288) Pub Date : 2019-07-01
    Jules Smith‐Ferguson, Madeleine Beekman

    The question ‘what is an individual’ does not often arise in studies within the field of behavioural ecology. Generally behavioural ecologists do not think about what makes an individual because they tend to use intuitive working concepts of individuality. Rarely do they explicitly mention how individuality affects their experimental design and interpretation of results. By contrast, the concept of individuality continues to intrigue philosophers of biology. It is interesting that while philosophers of biology debate definitions of individuality, biologists generally use the concept of individuality every day without much thought. Here we review the philosophical approaches to defining biological individuality, and illustrate how the biological individuality concepts used by biologists are affected by their study question and choice of organism. We clarify the behavioural perspective of biological individuality by introducing the concept of the behavioural individual. The notion of the behavioural individual is particularly interesting when explored in less‐conventional study organisms. By including less‐conventional organisms, it becomes clear why the concept of biological individuality is usually intuitive in behavioural ecology.

    更新日期:2019-07-02
  • Multimodal communication and language origins: integrating gestures and vocalizations
    Biol. Rev. (IF 10.288) Pub Date : 2019-06-27
    Marlen Fröhlich, Christine Sievers, Simon W. Townsend, Thibaud Gruber, Carel P. van Schaik

    The presence of divergent and independent research traditions in the gestural and vocal domains of primate communication has resulted in major discrepancies in the definition and operationalization of cognitive concepts. However, in recent years, accumulating evidence from behavioural and neurobiological research has shown that both human and non‐human primate communication is inherently multimodal. It is therefore timely to integrate the study of gestural and vocal communication. Herein, we review evidence demonstrating that there is no clear difference between primate gestures and vocalizations in the extent to which they show evidence for the presence of key language properties: intentionality, reference, iconicity and turn‐taking. We also find high overlap in the neurobiological mechanisms producing primate gestures and vocalizations, as well as in ontogenetic flexibility. These findings confirm that human language had multimodal origins. Nonetheless, we note that in great apes, gestures seem to fulfil a carrying (i.e. predominantly informative) role in close‐range communication, whereas the opposite holds for face‐to‐face interactions of humans. This suggests an evolutionary shift in the carrying role from the gestural to the vocal stream, and we explore this transition in the carrying modality. Finally, we suggest that future studies should focus on the links between complex communication, sociality and cooperative tendency to strengthen the study of language origins.

    更新日期:2019-06-29
  • The ecology and evolution of autotomy
    Biol. Rev. (IF 10.288) Pub Date : 2019-06-25
    Zachary Emberts, Ignacio Escalante, Philip W. Bateman

    Autotomy, the self‐induced loss of a body part, occurs throughout Animalia. A lizard dropping its tail to escape predation is an iconic example, however, autotomy occurs in a diversity of other organisms. Octopuses can release their arms, crabs can drop their claws, and bugs can amputate their legs. The diversity of organisms that can autotomize body parts has led to a wealth of research and several taxonomically focused reviews. These reviews have played a crucial role in advancing our understanding of autotomy within their respective groups. However, because of their taxonomic focus, these reviews are constrained in their ability to enhance our understanding of autotomy. Here, we aim to synthesize research on the ecology and evolution of autotomy throughout Animalia, building a unified framework on which future studies can expand. We found that the ability to drop an appendage has evolved multiple times throughout Animalia and that once autotomy has evolved, selection appears to act on the removable appendage to increase the efficacy and/or efficiency of autotomy. This could explain why some autotomizable body parts are so elaborate (e.g. brightly coloured). We also show that there are multiple benefits, and variable costs, associated with autotomy. Given this variation, we generate an economic theory of autotomy (modified from the economic theory of escape) which makes predictions about when an individual should resort to autotomy. Finally, we show that the loss of an autotomizable appendage can have numerous consequences on population and community dynamics. By taking this broad taxonomic approach, we identified patterns of autotomy that transcend specific lineages and highlight clear directions for future research.

    更新日期:2019-06-26
  • The chloride anion as a signalling effector
    Biol. Rev. (IF 10.288) Pub Date : 2019-06-23
    Ángel G. Valdivieso, Tomás A. Santa‐Coloma

    The specific role of the chloride anion (Cl−) as a signalling effector or second messenger has been increasingly recognized in recent years. It could represent a key factor in the regulation of cellular homeostasis. Changes in intracellular Cl− concentration affect diverse cellular functions such as gene and protein expression and activities, post‐translational modifications of proteins, cellular volume, cell cycle, cell proliferation and differentiation, membrane potential, reactive oxygen species levels, and intracellular/extracellular pH. Cl− also modulates functions in different organelles, including endosomes, phagosomes, lysosomes, endoplasmic reticulum, and mitochondria. A better knowledge of Cl− signalling could help in understanding the molecular and metabolic changes seen in pathologies with altered Cl− transport or under physiological conditions. Here we review relevant evidence supporting the role of Cl− as a signalling effector.

    更新日期:2019-06-24
  • Effects of nutrient limitation on sperm and seminal fluid: a systematic review and meta‐analysis
    Biol. Rev. (IF 10.288) Pub Date : 2019-06-19
    Erin L. Macartney, Angela J. Crean, Shinichi Nakagawa, Russell Bonduriansky

    Theory predicts that costly sexual traits should be reduced when individuals are in poor condition (i.e. traits should exhibit condition‐dependent expression). It is therefore widely expected that male ejaculate traits, such as sperm and seminal fluid, will exhibit reduced quantity and quality when dietary nutrients are limited. However, reported patterns of ejaculate condition dependence are highly variable, and there has been no comprehensive synthesis of underlying sources of such variation in condition‐dependent responses. In particular, it remains unclear whether all ejaculate traits are equally sensitive to nutrient intake, and whether such traits are particularly sensitive to certain dietary nutrients, respond more strongly to nutrients during specific life stages, or respond more strongly in some taxonomic groups. We systematically reviewed these potential sources of variation through a meta‐analysis across 50 species of arthropods and vertebrates (from 71 papers and 348 effect sizes). We found that overall, ejaculate traits are moderately reduced when dietary nutrients are limited, but we also detected substantial variation in responses. Seminal fluid quantity was strongly and consistently condition dependent, while sperm quantity was moderately condition dependent. By contrast, aspects of sperm quality (particularly sperm viability and morphology) were less consistently reduced under nutrient limitation. Ejaculate traits tended to respond in a condition‐dependent manner to a wide range of dietary manipulations, especially to caloric and protein restriction. Finally, while all major taxa for which sufficient data exist (i.e. arthropods, mammals, fish) showed condition dependence of ejaculate traits, we detected some taxonomic differences in the life stage that is most sensitive to nutrient limitation, and in the degree of condition dependence of specific ejaculate traits. Together, these biologically relevant factors accounted for nearly 20% of the total variance in ejaculate responses to nutrient limitation. Interestingly, body size showed considerably stronger condition‐dependent responses compared to ejaculate traits, suggesting that ejaculate trait expression may be strongly canalised to protect important reproductive functions, or that the cost of producing an ejaculate is relatively low. Taken together, our findings show that condition‐dependence of ejaculate traits is taxonomically widespread, but there are also many interesting, biologically relevant sources of variation that require further investigation. In particular, further research is needed to understand the differences in selective pressures that result in differential patterns of ejaculate condition dependence across taxa and ejaculate traits.

    更新日期:2019-06-19
  • A way forward with eco evo devo: an extended theory of resource polymorphism with postglacial fishes as model systems
    Biol. Rev. (IF 10.288) Pub Date : 2019-06-19
    Skúli Skúlason, Kevin J. Parsons, Richard Svanbäck, Katja Räsänen, Moira M. Ferguson, Colin E. Adams, Per‐Arne Amundsen, Pia Bartels, Colin W. Bean, Janette W. Boughman, Göran Englund, Jóhannes Guðbrandsson, Oliver E. Hooker, Alan G. Hudson, Kimmo K. Kahilainen, Rune Knudsen, Bjarni K. Kristjánsson, Camille A‐L. Leblanc, Zophonías Jónsson, Gunnar Öhlund, Carl Smith, Sigurður S. Snorrason

    A major goal of evolutionary science is to understand how biological diversity is generated and altered. Despite considerable advances, we still have limited insight into how phenotypic variation arises and is sorted by natural selection. Here we argue that an integrated view, which merges ecology, evolution and developmental biology (eco evo devo) on an equal footing, is needed to understand the multifaceted role of the environment in simultaneously determining the development of the phenotype and the nature of the selective environment, and how organisms in turn affect the environment through eco evo and eco devo feedbacks. To illustrate the usefulness of an integrated eco evo devo perspective, we connect it with the theory of resource polymorphism (i.e. the phenotypic and genetic diversification that occurs in response to variation in available resources). In so doing, we highlight fishes from recently glaciated freshwater systems as exceptionally well‐suited model systems for testing predictions of an eco evo devo framework in studies of diversification. Studies on these fishes show that intraspecific diversity can evolve rapidly, and that this process is jointly facilitated by (i) the availability of diverse environments promoting divergent natural selection; (ii) dynamic developmental processes sensitive to environmental and genetic signals; and (iii) eco evo and eco devo feedbacks influencing the selective and developmental environments of the phenotype. We highlight empirical examples and present a conceptual model for the generation of resource polymorphism – emphasizing eco evo devo, and identify current gaps in knowledge.

    更新日期:2019-06-19
  • Secondary dispersal mechanisms of winged seeds: a review
    Biol. Rev. (IF 10.288) Pub Date : 2019-06-19
    Dagmar der Weduwen, Graeme D. Ruxton

    Winged seeds, or samaras, are believed to promote the long‐distance dispersal and invasive potential of wind‐dispersed trees, but the full dispersive potential of these seeds has not been well characterised. Previous research on the ecology of winged seeds has largely focussed on the initial abscission and primary dispersal of the samara, despite it being known that the primary wind dispersal of samaras is often over short distances, with only rare escapes to longer distance dispersal. Secondary dispersal, or the movement of the seeds from the initial dispersal area to the site of germination, has been largely ignored despite offering a likely important mechanism for the dispersal of samaras to microhabitats suitable for establishment. Herein, we synthesise what is known on the predation and secondary dispersal of winged seeds by multiple dispersive vectors, highlighting gaps in knowledge and offering suggestions for future research. Both hydrochory and zoochory offer the chance for samaroid seeds to disperse over longer distances than anemochory alone, but the effects of the wing structure on these dispersal mechanisms have not been well characterised. Furthermore, although some studies have investigated secondary dispersal in samaroid species, such studies are scarce and only rarely track seeds from source to seedling. Future research must be directed to studying the secondary dispersal of samaras by various vectors, in order to elucidate fully the invasive and colonisation potential of samaroid trees.

    更新日期:2019-06-19
  • Brain iron transport
    Biol. Rev. (IF 10.288) Pub Date : 2019-06-12
    Zhong‐Ming Qian; Ya Ke

    Brain iron is a crucial participant and regulator of normal physiological activity. However, excess iron is involved in the formation of free radicals, and has been associated with oxidative damage to neuronal and other brain cells. Abnormally high brain iron levels have been observed in various neurodegenerative diseases, including neurodegeneration with brain iron accumulation, Alzheimer's disease, Parkinson's disease and Huntington's disease. However, the key question of why iron levels increase in the relevant regions of the brain remains to be answered. A full understanding of the homeostatic mechanisms involved in brain iron transport and metabolism is therefore critical not only for elucidating the pathophysiological mechanisms responsible for excess iron accumulation in the brain but also for developing pharmacological interventions to disrupt the chain of pathological events occurring in these neurodegenerative diseases. Numerous studies have been conducted, but to date no effort to synthesize these studies and ideas into a systematic and coherent summary has been made, especially concerning iron transport across the luminal (apical) membrane of the capillary endothelium and the membranes of different brain cell types. Herein, we review key findings on brain iron transport, highlighting the mechanisms involved in iron transport across the luminal (apical) as well as the abluminal (basal) membrane of the blood–brain barrier, the blood–cerebrospinal fluid barrier, and iron uptake and release in neurons, oligodendrocytes, astrocytes and microglia within the brain. We offer suggestions for addressing the many important gaps in our understanding of this important topic, and provide new insights into the potential causes of abnormally increased iron levels in regions of the brain in neurodegenerative disorders.

    更新日期:2019-06-13
  • Assessing the utility of conserving evolutionary history
    Biol. Rev. (IF 10.288) Pub Date : 2019-05-31
    Caroline M. Tucker; Tracy Aze; Marc W. Cadotte; Juan L. Cantalapiedra; Chelsea Chisholm; Sandra Díaz; Richard Grenyer; Danwei Huang; Florent Mazel; William D. Pearse; Matthew W. Pennell; Marten Winter; Arne O. Mooers

    It is often claimed that conserving evolutionary history is more efficient than species‐based approaches for capturing the attributes of biodiversity that benefit people. This claim underpins academic analyses and recommendations about the distribution and prioritization of species and areas for conservation, but evolutionary history is rarely considered in practical conservation activities. One impediment to implementation is that arguments related to the human‐centric benefits of evolutionary history are often vague and the underlying mechanisms poorly explored. Herein we identify the arguments linking the prioritization of evolutionary history with benefits to people, and for each we explicate the purported mechanism, and evaluate its theoretical and empirical support. We find that, even after 25 years of academic research, the strength of evidence linking evolutionary history to human benefits is still fragile.

    更新日期:2019-05-31
  • Causes and effects of haploinsufficiency
    Biol. Rev. (IF 10.288) Pub Date : 2019-05-31
    Adam F. Johnson; Ha T. Nguyen; Reiner A. Veitia

    Haploinsufficiency is a form of genetic dominance and is the underlying mechanism of numerous human inherited conditions in which the causal genes are sensitive to altered dosage. This review examines the poorly understood relationships between haploinsufficiency, dosage sensitivity and genetic dominance, whose common theme is the existence of nonlinear relationships between genotype and phenotype. We present an up‐to‐date account of the bases of haploinsufficiency from the perspective of theoretical and experimental models. We also discuss human conditions caused by haploinsufficiency, including developmental syndromes and cancer. Connections between the understanding of these conditions' genetic mechanisms and advances in treatments are also described.

    更新日期:2019-05-31
  • Vectors with autonomy: what distinguishes animal‐mediated nutrient transport from abiotic vectors?
    Biol. Rev. (IF 10.288) Pub Date : 2019-05-27
    Alexandra G. McInturf; Lea Pollack; Louie H. Yang; Orr Spiegel

    Animal movements are important drivers of nutrient redistribution that can affect primary productivity and biodiversity across various spatial scales. Recent work indicates that incorporating these movements into ecosystem models can enhance our ability to predict the spatio‐temporal distribution of nutrients. However, the role of animal behaviour in animal‐mediated nutrient transport (i.e. active subsidies) remains under‐explored. Here we review the current literature on active subsidies to show how the behaviour of active subsidy agents makes them both ecologically important and qualitatively distinct from abiotic processes (i.e. passive subsidies). We first propose that animal movement patterns can create similar ecological effects (i.e. press and pulse disturbances) in recipient ecosystems, which can be equal in magnitude to or greater than those of passive subsidies. We then highlight three key behavioural features distinguishing active subsidies. First, organisms can transport nutrients counter‐directionally to abiotic forces and potential energy gradients (e.g. upstream). Second, unlike passive subsidies, organisms respond to the patterns of nutrients that they generate. Third, animal agents interact with each other. The latter two features can form positive‐ or negative‐feedback loops, creating patterns in space or time that can reinforce nutrient hotspots in places of mass aggregations and/or create lasting impacts within ecosystems. Because human‐driven changes can affect both the space‐use of active subsidy species and their composition at both population (i.e. individual variation) and community levels (i.e. species interactions), predicting patterns in nutrient flows under future modified environmental conditions depends on understanding the behavioural mechanisms that underlie active subsidies and variation among agents' contributions. We conclude by advocating for the integration of animal behaviour, animal movement data, and individual variation into future conservation efforts in order to provide more accurate and realistic assessments of changing ecosystem function.

    更新日期:2019-05-28
  • Root extracellular traps versus neutrophil extracellular traps in host defence, a case of functional convergence?
    Biol. Rev. (IF 10.288) Pub Date : 2019-05-27
    Azeddine Driouich; Carine Smith; Marc Ropitaux; Marie Chambard; Isabelle Boulogne; Sophie Bernard; Marie‐Laure Follet‐Gueye; Maïté Vicré; John Moore

    The root cap releases cells that produce massive amounts of mucilage containing polysaccharides, proteoglycans, extracellular DNA (exDNA) and a variety of antimicrobial compounds. The released cells – known as border cells or border‐like cells – and mucilage secretions form networks that are defined as root extracellular traps (RETs). RETs are important players in root immunity. In animals, phagocytes are some of the most abundant white blood cells in circulation and are very important for immunity. These cells combat pathogens through multiple defence mechanisms, including the release of exDNA‐containing extracellular traps (ETs). Traps of neutrophil origin are abbreviated herein as NETs. Similar to phagocytes, plant root cap‐originating cells actively contribute to frontline defence against pathogens. RETs and NETs are thus components of the plant and animal immune systems, respectively, that exhibit similar compositional and functional properties. Herein, we describe and discuss the formation, molecular composition and functional similarities of these similar but different extracellular traps.

    更新日期:2019-05-28
  • Comparative molecular cell biology of phototrophic euglenids and parasitic trypanosomatids sheds light on the ancestor of Euglenozoa
    Biol. Rev. (IF 10.288) Pub Date : 2019-05-16
    Matej Vesteg; Lucia Hadariová; Anton Horváth; Carlos E. Estraño; Steven D. Schwartzbach; Juraj Krajčovič

    Parasitic trypanosomatids and phototrophic euglenids are among the most extensively studied euglenozoans. The phototrophic euglenid lineage arose relatively recently through secondary endosymbiosis between a phagotrophic euglenid and a prasinophyte green alga that evolved into the euglenid secondary chloroplast. The parasitic trypanosomatids (i.e. Trypanosoma spp. and Leishmania spp.) and the freshwater phototrophic euglenids (i.e. Euglena gracilis) are the most evolutionary distant lineages in the Euglenozoa phylogenetic tree. The molecular and cell biological traits they share can thus be considered as ancestral traits originating in the common euglenozoan ancestor. These euglenozoan ancestral traits include common mitochondrial presequence motifs, respiratory chain complexes containing various unique subunits, a unique ATP synthase structure, the absence of mitochondria‐encoded transfer RNAs (tRNAs), a nucleus with a centrally positioned nucleolus, closed mitosis without dissolution of the nuclear membrane and nucleoli, a nuclear genome containing the unusual ‘J’ base (β‐D‐glucosyl‐hydroxymethyluracil), processing of nucleus‐encoded precursor messenger RNAs (pre‐mRNAs) via spliced‐leader RNA (SL‐RNA) trans‐splicing, post‐transcriptional gene silencing by the RNA interference (RNAi) pathway and the absence of transcriptional regulation of nuclear gene expression. Mitochondrial uridine insertion/deletion RNA editing directed by guide RNAs (gRNAs) evolved in the ancestor of the kinetoplastid lineage. The evolutionary origin of other molecular features known to be present only in either kinetoplastids (i.e. polycistronic transcripts, compaction of nuclear genomes) or euglenids (i.e. monocistronic transcripts, huge genomes, many nuclear cis‐spliced introns, polyproteins) is unclear.

    更新日期:2019-05-16
  • Neural mechanisms of auditory species recognition in birds
    Biol. Rev. (IF 10.288) Pub Date : 2019-05-07
    Matthew I. M. Louder; Shelby Lawson; Kathleen S. Lynch; Christopher N. Balakrishnan; Mark E. Hauber

    Auditory communication in humans and other animals frequently takes place in noisy environments with many co‐occurring signallers. Receivers are thus challenged to rapidly recognize salient auditory signals and filter out irrelevant sounds. Most bird species produce a variety of complex vocalizations that function to communicate with other members of their own species and behavioural evidence broadly supports preferences for conspecific over heterospecific sounds (auditory species recognition). However, it remains unclear whether such auditory signals are categorically recognized by the sensory and central nervous system. Here, we review 53 published studies that compare avian neural responses between conspecific versus heterospecific vocalizations. Irrespective of the techniques used to characterize neural activity, distinct nuclei of the auditory forebrain are consistently shown to be repeatedly conspecific selective across taxa, even in response to unfamiliar individuals with distinct acoustic properties. Yet, species‐specific neural discrimination is not a stereotyped auditory response, but is modulated according to its salience depending, for example, on ontogenetic exposure to conspecific versus heterospecific stimuli. Neuromodulators, in particular norepinephrine, may mediate species recognition by regulating the accuracy of neuronal coding for salient conspecific stimuli. Our review lends strong support for neural structures that categorically recognize conspecific signals despite the highly variable physical properties of the stimulus. The available data are in support of a ‘perceptual filter’‐based mechanism to determine the saliency of the signal, in that species identity and social experience combine to influence the neural processing of species‐specific auditory stimuli. Finally, we present hypotheses and their testable predictions, to propose next steps in species‐recognition research into the emerging model of the neural conceptual construct in avian auditory recognition.

    更新日期:2019-05-16
  • A general framework for propagule dispersal in mangroves
    Biol. Rev. (IF 10.288) Pub Date : 2019-05-06
    Tom Van der Stocken; Alison K. S. Wee; Dennis J. R. De Ryck; Bram Vanschoenwinkel; Daniel A. Friess; Farid Dahdouh‐Guebas; Marc Simard; Nico Koedam; Edward L. Webb

    Dispersal allows species to shift their distributions in response to changing climate conditions. As a result, dispersal is considered a key process contributing to a species' long‐term persistence. For many passive dispersers, fluid dynamics of wind and water fuel these movements and different species have developed remarkable adaptations for utilizing this energy to reach and colonize suitable habitats. The seafaring propagules (fruits and seeds) of mangroves represent an excellent example of such passive dispersal. Mangroves are halophytic woody plants that grow in the intertidal zones along tropical and subtropical shorelines and produce hydrochorous propagules with high dispersal potential. This results in exceptionally large coastal ranges across vast expanses of ocean and allows species to shift geographically and track the conditions to which they are adapted. This is particularly relevant given the challenges presented by rapid sea‐level rise, higher frequency and intensity of storms, and changes in regional precipitation and temperature regimes. However, despite its importance, the underlying drivers of mangrove dispersal have typically been studied in isolation, and a conceptual synthesis of mangrove oceanic dispersal across spatial scales is lacking. Here, we review current knowledge on mangrove propagule dispersal across the various stages of the dispersal process. Using a general framework, we outline the mechanisms and ecological processes that are known to modulate the spatial patterns of mangrove dispersal. We show that important dispersal factors remain understudied and that adequate empirical data on the determinants of dispersal are missing for most mangrove species. This review particularly aims to provide a baseline for developing future research agendas and field campaigns, filling current knowledge gaps and increasing our understanding of the processes that shape global mangrove distributions.

    更新日期:2019-05-16
  • Forest fragmentation in China and its effect on biodiversity
    Biol. Rev. (IF 10.288) Pub Date : 2019-05-06
    Jiajia Liu; David A. Coomes; Luke Gibson; Guang Hu; Jinliang Liu; Yangqing Luo; Chuping Wu; Mingjian Yu

    Land‐use change is fragmenting natural ecosystems, with major consequences for biodiversity. This paper reviews fragmentation trends – historical and current – in China, the fourth largest country on Earth, and explores its consequences. Remote sensing makes it possible to track land‐use change at a global scale and monitor fragmentation of dwindling natural landscapes. Yet few studies have linked fragmentation mapped remotely with impacts on biodiversity within human‐modified landscapes. Recent reforestation programs have caused substantial increases in forest cover but have not stopped fragmentation, because the new forests are mostly monocultures that further fragment China's remnant old‐growth lowland forests that harbour the highest levels of biodiversity. Fragmentation – and associated biodiversity declines – is unevenly distributed in China's forests, being most problematic where agricultural expansion is occurring in the southwest and northeast, serious in the densely populated eastern regions where urbanisation and transport infrastructure are modifying landscapes, but less of a problem in other regions. Analyses of temporal trends show that the drivers of forest fragmentation are shifting from mainly agricultural expansion to urbanisation and infrastructure development. Most of China's old‐growth forests persist in small, isolated fragments from which many native species have disappeared, on land unsuitable for human utilisation. Fragmentation throughout China is likely to have major consequences on biodiversity conservation, but few studies have considered these large‐scale processes at the national level. Our review fills this research gap and puts forward a systematic perspective relevant to China and beyond.

    更新日期:2019-05-16
  • A global assessment of primate responses to landscape structure
    Biol. Rev. (IF 10.288) Pub Date : 2019-05-03
    Carmen Galán‐Acedo; Víctor Arroyo‐Rodríguez; Sabine J. Cudney‐Valenzuela; Lenore Fahrig

    Land‐use change modifies the spatial structure of terrestrial landscapes, potentially shaping the distribution, abundance and diversity of remaining species assemblages. Non‐human primates can be particularly vulnerable to landscape disturbances, but our understanding of this topic is far from complete. Here we reviewed all available studies on primates' responses to landscape structure. We found 34 studies of 71 primate species (24 genera and 10 families) that used a landscape approach. Most studies (82%) were from Neotropical forests, with howler monkeys being the most frequently studied taxon (56% of studies). All studies but one used a site‐landscape or a patch‐landscape study design, and frequently (34% of studies) measured landscape variables within a given radius from the edge of focal patches. Altogether, the 34 studies reported 188 responses to 17 landscape‐scale metrics. However, the majority of the studies (62%) quantified landscape predictors within a single spatial scale, potentially missing significant primate–landscape responses. To assess such responses accurately, landscape metrics need to be measured at the optimal scale, i.e. the spatial extent at which the primate–landscape relationship is strongest (so‐called ‘scale of effect’). Only 21% of studies calculated the scale of effect through multiscale approaches. Interestingly, the vast majority of studies that do not assess the scale of effect mainly reported null effects of landscape structure on primates, while most of the studies based on optimal scales found significant responses. These significant responses were primarily to landscape composition variables rather than landscape configuration variables. In particular, primates generally show positive responses to increasing forest cover, landscape quality indices and matrix permeability. By contrast, primates show weak responses to landscape configuration. In addition, half of the studies showing significant responses to landscape configuration metrics did not control for the effect of forest cover. As configuration metrics are often correlated with forest cover, this means that documented configuration effects may simply be driven by landscape‐scale forest loss. Our findings suggest that forest loss (not fragmentation) is a major threat to primates, and thus, preventing deforestation (e.g. through creation of reserves) and increasing forest cover through restoration is critically needed to mitigate the impact of land‐use change on our closest relatives. Increasing matrix functionality can also be critical, for instance by promoting anthropogenic land covers that are similar to primates' habitat.

    更新日期:2019-05-16
  • Comparison of the ecology and evolution of plants with a generalist bird pollination system between continents and islands worldwide
    Biol. Rev. (IF 10.288) Pub Date : 2019-05-03
    Stefan Abrahamczyk

    Thousands of plant species worldwide are dependent on birds for pollination. While the ecology and evolution of interactions between specialist nectarivorous birds and the plants they pollinate is relatively well understood, very little is known on pollination by generalist birds. The flower characters of this pollination syndrome are clearly defined but the geographical distribution patterns, habitat preferences and ecological factors driving the evolution of generalist‐bird‐pollinated plant species have never been analysed. Herein I provide an overview, compare the distribution of character states for plants growing on continents with those occurring on oceanic islands and discuss the environmental factors driving the evolution of both groups. The ecological niches of generalist‐bird‐pollinated plant species differ: on continents these plants mainly occur in habitats with pronounced climatic seasonality whereas on islands generalist‐bird‐pollinated plant species mainly occur in evergreen forests. Further, on continents generalist‐bird‐pollinated plant species are mostly shrubs and other large woody species producing numerous flowers with a self‐incompatible reproductive system, while on islands they are mostly small shrubs producing fewer flowers and are self‐compatible. This difference in character states indicates that diverging ecological factors are likely to have driven the evolution of these groups: on continents, plants that evolved generalist bird pollination escape from pollinator groups that tend to maintain self‐pollination by installing feeding territories in single flowering trees or shrubs, such as social bees or specialist nectarivorous birds. This pattern is more pronounced in the New compared to the Old World. By contrast, on islands, plants evolved generalist bird pollination as an adaptation to birds as a reliable pollinator group, a pattern previously known from plants pollinated by specialist nectarivorous birds in tropical mountain ranges. Additionally, I discuss the evolutionary origins of bird pollination systems in comparison to systems involving specialist nectarivorous birds and reconstruct the bird pollination system of Hawaii, which may represent an intermediate between a specialist and generalist bird pollination system. I also discuss the interesting case of Australia, where it is difficult to distinguish between specialist and generalist bird pollination systems.

    更新日期:2019-05-16
  • Fungal evolution: major ecological adaptations and evolutionary transitions
    Biol. Rev. (IF 10.288) Pub Date : 2019-04-25
    Miguel A. Naranjo‐Ortiz; Toni Gabaldón

    Fungi are a highly diverse group of heterotrophic eukaryotes characterized by the absence of phagotrophy and the presence of a chitinous cell wall. While unicellular fungi are far from rare, part of the evolutionary success of the group resides in their ability to grow indefinitely as a cylindrical multinucleated cell (hypha). Armed with these morphological traits and with an extremely high metabolical diversity, fungi have conquered numerous ecological niches and have shaped a whole world of interactions with other living organisms. Herein we survey the main evolutionary and ecological processes that have guided fungal diversity. We will first review the ecology and evolution of the zoosporic lineages and the process of terrestrialization, as one of the major evolutionary transitions in this kingdom. Several plausible scenarios have been proposed for fungal terrestralization and we here propose a new scenario, which considers icy environments as a transitory niche between water and emerged land. We then focus on exploring the main ecological relationships of Fungi with other organisms (other fungi, protozoans, animals and plants), as well as the origin of adaptations to certain specialized ecological niches within the group (lichens, black fungi and yeasts). Throughout this review we use an evolutionary and comparative‐genomics perspective to understand fungal ecological diversity. Finally, we highlight the importance of genome‐enabled inferences to envision plausible narratives and scenarios for important transitions.

    更新日期:2019-05-16
  • Molecular interplay of autophagy and endocytosis in human health and diseases
    Biol. Rev. (IF 10.288) Pub Date : 2019-04-15
    Kewal K. Mahapatra; Debasna P. Panigrahi; Prakash P. Praharaj; Chandra S. Bhol; Srimanta Patra; Soumya R. Mishra; Bishnu P. Behera; Sujit K. Bhutia

    Autophagy, an evolutionarily conserved process for maintaining the physio‐metabolic equilibrium of cells, shares many common effector proteins with endocytosis. For example, tethering proteins involved in fusion like Ras‐like GTPases (Rabs), soluble N‐ethylmaleimide sensitive factor attachment protein receptors (SNAREs), lysosomal‐associated membrane protein (LAMP), and endosomal sorting complex required for transport (ESCRT) have a dual role in endocytosis and autophagy, and the trafficking routes of these processes converge at lysosomes. These common effectors indicate an association between budding and fusion of membrane‐bound vesicles that may have a substantial role in autophagic lysosome reformation, by sensing cellular stress levels. Therefore, autophagy–endocytosis crosstalk may be significant and implicates a novel endocytic regulatory pathway of autophagy. Moreover, endocytosis has a pivotal role in the intake of signalling molecules, which in turn activates cascades that can result in pathophysiological conditions. This review discusses the basic mechanisms of this crosstalk and its implications in order to identify potential novel therapeutic targets for various human diseases.

    更新日期:2019-05-16
  • Two potential evolutionary origins of the fruiting bodies of the dictyostelid slime moulds
    Biol. Rev. (IF 10.288) Pub Date : 2019-04-15
    Jenks Hehmeyer

    Dictyostelium discoideum and the other dictyostelid slime moulds (‘social amoebae’) are popular model organisms best known for their demonstration of sorocarpic development. In this process, many cells aggregate to form a multicellular unit that ultimately becomes a fruiting body bearing asexual spores. Several other unrelated microorganisms undergo comparable processes, and in some it is evident that their multicellular development evolved from the differentiation process of encystation. While it has been argued that the dictyostelid fruiting body had similar origins, it has also been proposed that dictyostelid sorocarpy evolved from the unicellular fruiting process found in other amoebozoan slime moulds. This paper reviews the developmental biology of the dictyostelids and other relevant organisms and reassesses the two hypotheses on the evolutionary origins of dictyostelid development. Recent advances in phylogeny, genetics, and genomics and transcriptomics indicate that further research is necessary to determine whether or not the fruiting bodies of the dictyostelids and their closest relatives, the myxomycetes and protosporangids, are homologous.

    更新日期:2019-05-16
  • Global effects of non‐native tree species on multiple ecosystem services
    Biol. Rev. (IF 10.288) Pub Date : 2019-04-11
    Pilar Castro‐Díez; Ana Sofia Vaz; Joaquim S. Silva; Marcela van Loo; Álvaro Alonso; Cristina Aponte; Álvaro Bayón; Peter J. Bellingham; Mariana C. Chiuffo; Nicole DiManno; Kahua Julian; Susanne Kandert; Nicola La Porta; Hélia Marchante; Hamish G. Maule; Margaret M. Mayfield; Daniel Metcalfe; M. Cristina Monteverdi; Martín A. Núñez; Rebecca Ostertag; Ingrid M. Parker; Duane A. Peltzer; Luke J. Potgieter; Maia Raymundo; Donald Rayome; Orna Reisman‐Berman; David M. Richardson; Ruben E. Roos; Asunción Saldaña; Ross T. Shackleton; Agostina Torres; Melinda Trudgen; Josef Urban; Joana R. Vicente; Montserrat Vilà; Tiina Ylioja; Rafael D. Zenni; Oscar Godoy

    Non‐native tree (NNT) species have been transported worldwide to create or enhance services that are fundamental for human well‐being, such as timber provision, erosion control or ornamental value; yet NNTs can also produce undesired effects, such as fire proneness or pollen allergenicity. Despite the variety of effects that NNTs have on multiple ecosystem services, a global quantitative assessment of their costs and benefits is still lacking. Such information is critical for decision‐making, management and sustainable exploitation of NNTs. We present here a global assessment of NNT effects on the three main categories of ecosystem services, including regulating (RES), provisioning (PES) and cultural services (CES), and on an ecosystem disservice (EDS), i.e. pollen allergenicity. By searching the scientific literature, country forestry reports, and social media, we compiled a global data set of 1683 case studies from over 125 NNT species, covering 44 countries, all continents but Antarctica, and seven biomes. Using different meta‐analysis techniques, we found that, while NNTs increase most RES (e.g. climate regulation, soil erosion control, fertility and formation), they decrease PES (e.g. NNTs contribute less than native trees to global timber provision). Also, they have different effects on CES (e.g. increase aesthetic values but decrease scientific interest), and no effect on the EDS considered. NNT effects on each ecosystem (dis)service showed a strong context dependency, varying across NNT types, biomes and socio‐economic conditions. For instance, some RES are increased more by NNTs able to fix atmospheric nitrogen, and when the ecosystem is located in low‐latitude biomes; some CES are increased more by NNTs in less‐wealthy countries or in countries with higher gross domestic products. The effects of NNTs on several ecosystem (dis)services exhibited some synergies (e.g. among soil fertility, soil formation and climate regulation or between aesthetic values and pollen allergenicity), but also trade‐offs (e.g. between fire regulation and soil erosion control). Our analyses provide a quantitative understanding of the complex synergies, trade‐offs and context dependencies involved for the effects of NNTs that is essential for attaining a sustained provision of ecosystem services.

    更新日期:2019-05-16
Contents have been reproduced by permission of the publishers.
导出
全部期刊列表>>
2020新春特辑
限时免费阅读临床医学内容
ACS材料视界
科学报告最新纳米科学与技术研究
清华大学化学系段昊泓
自然科研论文编辑服务
中国科学院大学楚甲祥
中国科学院微生物研究所潘国辉
中国科学院化学研究所
课题组网站
X-MOL
北京大学分子工程苏南研究院
华东师范大学分子机器及功能材料
中山大学化学工程与技术学院
试剂库存
天合科研
down
wechat
bug