Genetic regulation of embryo death and senescence

The survival of the preimplantation mammalian embryo depends not only on providing the proper conditions for normal development but also on acquiring the mechanisms by which embryos cope with adversity. The ability of the early conceptus to resist stress as development proceeds may be regulated by diverse factors such as the attainment of a cell death program and protective mechanisms involving stress-induced genes and/or cell cycle modulators. This paper reviews the recent research on the genetic regulation of early embryo cell death and senescence focussing on the bovine species where possible. The different modes of cell death will be explained, clarifying the confusing cell death terminology, by advocating the recommendations set forth by the Cell Death Nomenclature Committee to extend to the embryology research field. Specific pro-death and anti-death genes will be discussed with reference to their expression patterns during early mammalian embryogenesis.     

Variation in contributions to teaching by meerkats

Recent evidence from cooperative insect, bird and mammal societies has challenged the assumption that teaching is restricted to humans. However, little is known about the factors affecting the degree to which individuals in such societies contribute to teaching. Here, I examine variation in contributions to teaching in meerkats, where older group members teach pups to handle difficult prey. I show that investment in teaching varies with characteristics of pups, helpers, groups and ecological conditions. Although prior experience in caring for pups did not significantly influence teaching behaviour, younger helpers, which were still investing in growth, contributed less to teaching than older individuals. This suggests that, in common with other cooperative activities, contributions to teaching vary with the costs experienced by individual group members. However, in contrast to other forms of helping in meerkats, I detected no effects of nutritional state on teaching, suggesting that it carries relatively low costs. In species where individuals can potentially gain direct or indirect fitness benefits from facilitating learning in others, low costs divided among multiple group members may help tip the balance towards selection for teaching.     

Avoid your neighbours: size-determined spatial distribution patterns among northern pike individuals

The spatial distribution of individual animals may both cause and be caused by intra- and/or interspecific interactions. This work aims primarily on effects of intraspecific interactions. Agonistic and unequally strong interactions among conspecifics should make the within-population distribution of individuals to be characterised by spatial avoidance of potentially risky conspecifics, according to the individual risks perceived. This process should affect individual performance and involve individual tradeoffs, as failing to adequately avoid risky conspecifics could incur unnecessary costs, while, at the same time, successful conspecific avoidance may reduce access to patches favourable for e.g. foraging or sheltering. Intraspecific agonistic behaviours, such as cannibalism and competition, are likely to have prominent effects in size-structured populations. It is therefore reasonable to assume spatial avoidance of intraspecific risks according to individuals' size relationships in such populations. With this field investigation I show that individuals of northern pike spatially avoid larger conspecifics. This avoidance creates a size-influenced and spatially clumped distribution pattern among pike individuals. At low pike densities, however, distances between individuals increase, allowing for an even distribution pattern to appear. The spatial distribution patterns among piscivore individuals should affect both the individual performance of predators and the potential for spatial anti-predatory responses of their prey, and hence be a factor in consumer–resource interactions.     

Where Next? Group Coordination and Collective Decision Making by Primates

Primate groups need to remain coordinated in their activities and collectively decide when and where to travel if they are to accrue the benefits and minimize the costs of sociality. The achievement of coordinated activity and group decision making therefore has important implications for individual survival and reproduction. The aim of this special issue is to bring together a collection of empirical, theoretical, and commentary articles by primatologists studying this rapidly expanding topic. In this article, we introduce the contributions within the special issue and provide a background to the topic. We begin by focusing on decisions that involve a collective transition between a resting and a moving state, a transition we term making the move. We examine whether specific predeparture behaviors seen during transitions represent intentional processes or more simple response facilitation. Next we classify decisions according to the contribution of individual group members, and describe how, and why, certain individuals can have a disproportionate influence over group-mates?? behavior. We then review how primate groups make decisions on the move. In particular, we focus on how variability in group size and spatial organization helps or hinders information transmission and coordination. We end with a discussion of new tools and methodology that will allow future investigators to address some outstanding questions in primate coordination and decision-making research. We conclude that a better integration of concepts and terminology, along with a focus on how individuals integrate environmental and social information, will be critical to developing a satisfactory understanding of collective patterns of behavior in primate systems.     

优化教学活动,提高教学质量——组织胚胎学教学方法的探索与实践

对组织胚胎学课程的教学改革模式进行分析,并根据多年教学实践经验,结合中医院校的教学现状,提出要从优化教学内容、创新教学手段、采用多种教学方法等方面入手,以进一步提高组织胚胎学课程的教学质量.     

植物胚胎学在中国的发展

植物胚胎学在中国的发展大体可划分为 3个时期 :(1)初始时期 ,主要在裸子植物胚胎发育的观察和实验研究方面开展了一些工作。(2 )在 2 0世纪 5 0年代后的十几年是学科的建立时期。这期间培养了一些植物胚胎学的人才和开展了许多胚胎发育的描述性研究。 (3)近二十几年 ,随着国际上这一学科的发展 ,进入植物生殖生物学的发展时期。在这一时期中 ,以被子植物为对象开展了多方面的研究。第一 ,在结构与功能关系方面 ,研究小孢子发生过程中细胞质改组 ,雄配子体发育中营养核与生殖细胞的关系 ;雄性生殖单位与雌性生殖单位的结构 ,细胞质遗传的细胞学机理 ;生殖系统中的细胞骨架和传递细胞的结构与分布 ;胚珠中细胞衰退与其物质的迁移。第二 ,生理活动方面 ,研究钙在受精过程中的作用 ,ATP酶在胚珠物质运输中的参与 ,受精过程中与识别作用相关的柱头表膜和精细胞质膜蛋白的分离与组分的分析。第三 ,与育种相关的胚胎学研究 ,包括雄性不育性、无融合生殖及远缘杂交等。在以裸子植物为对象的研究中 ,首先是对许多我国特有的属种的胚胎发育作出详细的描述 ,以及为讨论系统位置提供胚胎学佐证。这方面的研究是独具特色的。其次 ,在受精作用和精细胞的光镜和电镜的研究也获得了突出的成果     

Haeckel's ABC of evolution and development

One of the central, unresolved controversies in biology concerns the distribution of primitive versus advanced characters at different stages of vertebrate development. This controversy has major implications for evolutionary developmental biology and phylogenetics. Ernst Haeckel addressed the issue with his Biogenetic Law, and his embryo drawings functioned as supporting data. We re-examine Haeckel's work and its significance for modern efforts to develop a rigorous comparative framework for developmental studies. Haeckel's comparative embryology was evolutionary but non-quantitative. It was based on developmental sequences, and treated heterochrony as a sequence change. It is not always clear whether he believed in recapitulation of single characters or entire stages. The Biogenetic Law is supported by several recent studies -- if applied to single characters only. Haeckel's important but overlooked alphabetical analogy of evolution and development is an advance on von Baer. Haeckel recognized the evolutionary diversity in early embryonic stages, in line with modern thinking. He did not necessarily advocate the strict form of recapitulation and terminal addition commonly attributed to him. Haeckel's much-criticized embryo drawings are important as phylogenetic hypotheses, teaching aids, and evidence for evolution. While some criticisms of the drawings are legitimate, others are more tendentious. In opposition to Haeckel and his embryo drawings, Wilhelm His made major advances towards developing a quantitative comparative embryology based on morphometrics. Unfortunately His's work in this area is largely forgotten. Despite his obvious flaws, Haeckel can be seen as the father of a sequence-based phylogenetic embryology.     

科学典故在组织胚胎学教学中的应用

人体组织胚胎学是一门医学形态学课程,也是医学生进入人体奥秘大门的一把重要钥匙,但形态结构中繁多的记忆内容常常让学生感到学习枯燥,因而更需要授课教师通过不同形式的教学策略引导学生领会其中的乐趣和科学意义。在众多的教学方法和教学手段中,适当引用教学内容相关的科学典故和科学名人,能在潜移默化中培养学生的学习兴趣,理解相关的理论知识,改善教学效果。本文作者整理了一些组织胚胎学教学内容相关的科学典故及其在教学中的应用,供同行交流和医学生参考学习。     

定向免费医学生组织学与胚胎学教学改革初探

为了提高基层医疗水平,国家启动了免费医学生培养计划,组织学与胚胎学是免费医学生一门必修课程,本课程为后续相关医学课程的基础,此课程学习得好与坏直接影响相关医学课程的学习,甚至影响免费医学生的培养质量,因此加强免费医学生组织学与胚胎学教学改革十分必要。     

Thomas Hunt Morgan as an Embryologist: The View from Bryn Mawr

Thomas Hunt Morgan taught at Bryn Mawr College from 1891 until1904. During his years there he concentrated his research interestson embryology; he included regeneration as an integral partof development. This article maintains that Morgan did not abandonhis interest in embryology when he became a geneticist at Columbia,but it deals mainly with his teaching and research while atBryn Mawr. He worked on the development of a great diversityof organisms, plant and animal, he used widely differing experimentalmethods to investigate them, and he concerned himself with manydifferent general and special problems. He strove to investigateproblems that were directly soluble by experimental intervention,and was highly critical, in the best possible way, of the experimentsand interpretations made by his contemporaries, who regardedhim as a leader. He exerted his influence on developmental biologynot only through his research, but also through a number offine textbooks, and by his teaching. During his Bryn Mawr yearshe encouraged his students, undergraduate and graduate, to carryout independent research. He sometimes published with them asco-author, but dozens of articles by his students were publishedwithout carrying Morgan's name as co-author.     

植物胚胎学在中国的发展

植物胚胎学在中国的发展大体可划分为3个时期: (1) 初始时期, 主要在裸子植物胚胎发育的观察和实验研究方面开展了一些工作. (2) 在20世纪50年代后的十几年是学科的建立时期.这期间培养了一些植物胚胎学的人才和开展了许多胚胎发育的描述性研究.(3)近二十几年,随着国际上这一学科的发展,进入植物生殖生物学的发展时期.在这一时期中,以被子植物为对象开展了多方面的研究.第一,在结构与功能关系方面,研究小孢子发生过程中细胞质改组,雄配子体发育中营养核与生殖细胞的关系;雄性生殖单位与雌性生殖单位的结构,细胞质遗传的细胞学机理;生殖系统中的细胞骨架和传递细胞的结构与分布;胚珠中细胞衰退与其物质的迁移.第二,生理活动方面,研究钙在受精过程中的作用,ATP酶在胚珠物质运输中的参与,受精过程中与识别作用相关的柱头表膜和精细胞质膜蛋白的分离与组分的分析.第三,与育种相关的胚胎学研究,包括雄性不育性、无融合生殖及远缘杂交等.在以裸子植物为对象的研究中,首先是对许多我国特有的属种的胚胎发育作出详细的描述,以及为讨论系统位置提供胚胎学佐证.这方面的研究是独具特色的.其次,在受精作用和精细胞的光镜和电镜的研究也获得了突出的成果.     

Individual heterogeneity and capture–recapture models: what,why and how?

Variation between and within individuals in life history traits is ubiquitous in natural populations. When affecting fitness‐related traits such as survival or reproduction, individual heterogeneity plays a key role in population dynamics and life history evolution. However, it is only recently that properly accounting for individual heterogeneity when studying population dynamics of free‐ranging populations has been made possible through the development of appropriate statistical models. We aim here to review case studies of individual heterogeneity in the context of capture–recapture models for the estimation of population size and demographic parameters with imperfect detection. First, we define what individual heterogeneity means and clarify the terminology used in the literature. Second, we review the literature and illustrate why individual heterogeneity is used in capture–recapture studies by focusing on the detection of life‐history tradeoffs, including senescence. Third, we explain how to model individual heterogeneity in capture–recapture models and provide the code to fit these models ( https://github.com/oliviergimenez/indhet_in_CRmodels ). The distinction is made between situations in which heterogeneity is actually measured and situations in which part of the heterogeneity remains unobserved. Regarding the latter, we outline recent developments of random‐effect models and finite‐mixture models. Finally, we discuss several avenues for future research.     

The influence of size-dependent life-history traits on the structure and dynamics of populations and communities

Individual organisms often show pronounced changes in body size throughout life with concomitant changes in ecological performance. We synthesize recent insight into the relationship between size dependence in individual life history and population dynamics. Most studies have focused on size‐dependent life‐history traits and population size‐structure in the highest trophic level, which generally leads to population cycles with a period equal to the juvenile delay. These cycles are driven by differences in competitiveness of differently sized individuals. In multi‐trophic systems, size dependence in life‐history traits at lower trophic levels may have consequences for both the dynamics and structure of communities, as size‐selective predation may lead to the occurrence of emergent Allee effects and the stabilization of predator–prey cycles. These consequences are linked to that individual development is density dependent. We conjecture that especially this population feedback on individual development may lead to new theoretical insight compared to theory based on unstructured or age‐dependent models. Density‐dependent individual development may also cause individuals to realize radically different life histories, dependent on the state and dynamics of the population during their life and may therefore have consequences for individual behaviour or the evolution of life‐history traits as well.     

Exchangeability in multivariate Markov chain models.

Time-homogeneous Markov chain models with state space [0, 1]k are useful in analysis of binary follow-up data on k individuals that interact. The number of parameters increases exponentially with k so more restrictive models are imperative for statistical inference. The hypothesis that the matrix of transition probabilities is invariant under permutation of individuals is discussed. It is shown that if individuals are exchangeable, then the process counting the number of individuals occupying a given state is a Markov chain. This reduction of data is sufficient if either at most a single individual may change state between two consecutive time points or if a state is absorbing. Similar results are obtained for exchangeability within two subgroups. Inference in the multivariate process reduces to a univariate problem if individuals are independent given the group's previous response. It is shown how conditional independence could be tested assuming exchangeability. The different hypotheses re examined in an analysis of the occurrence of bacteria in milk samples of Danish dairy cattle.     

The spectrum of median craniofacial dysplasia

Given the multiple permutations in craniofacial malformations, classification of median craniofacial dysplasia or midline Tessier no. 0 to 14 clefts has been difficult and disjointed. In this review, the authors present a summary of normal embryology, prior terminology, and their proposed new classification system. Median craniofacial dysplasia has tissue agenesis and holoprosencephaly at one end (the hypoplasias), frontonasal hyperplasia and excessive tissue (the hyperplasias) at the other end, and abnormal splitting or clefting and normal tissue volume (dysraphia) occupying the middle portion of the spectrum. These three distinct subclassifications have different forms of anomalies within their groups.     

Plant intelligence: an alternative point of view

The concept of plant intelligence has been advanced by Trewavas as a potentially useful framework to guide those seeking to understand plant growth and development. In this short critique, the validity of this concept is critically assessed. Central to this critique is the proposition that the concept of the individual, to which intelligence and behaviour are intimately linked, cannot usefully be applied to plants. It is argued that the adaptive responses of plants are best appreciated if the importance of the autonomy of the individual organs is acknowledged. Although Trewavas does acknowledge the autonomy of organs by describing an individual plant as being 'a democratic confederation', that terminology implies a complexity to the interaction between organs which would demand a cogitative ability beyond that actually demonstrated in plants. It may be more appropriate to consider a plant as operating normally as a simple economic federation of many specialized economies (organs and cells). Occasionally, there can be a dramatic, and sometimes complex, reshaping of the economic balances, with the result that the fate of some or many of the individual cells will change. However, such major changes in growth and development are driven by a few simple events in an individual organ and cells. These driving events are more akin to small local revolutions in individual states than they are to democratic decisions in a sophisticated confederation.     

The psychophysiology of the emotions and personality

According to the need-informational approach the need is specific (essential) force of living organisms, procuring their connections with external environment for self-preservation and self-development, a source of living systems' activity in the surrounding world. Emotion-reflection in human and higher animals' brain of an urgent need and of probability (possibility) of its satisfaction. Emotion in its neurophysiological sense is an active state of a system of specialized brain structures, prompting the subject to change his behaviour so that to maximize or to minimize this state which determines the role of emotions in organization of goal-directed behaviour. Personality is individual unique composition and internal hierarchy of basic (vital, social, ideal) needs of a given human being, including their varieties of preservation and development, "for me" and "for others". The most important personality characteristic is which of those needs and for how long are dominant in the hierarchy of coexisting motives, which need is "supplied" by creative intuition (superconsciousness, according to K. S. Stanislavski?'s terminology).     

Unravelling the Philosophies Underlying ‘Animal Personality’ Studies: A Brief Re‐Appraisal of the Field

The last decade has seen lots of studies on ‘animal personality’ (i.e. the study of consistent between‐individual behavioural differences). As timely and promising as this field is, its development has come with a diversity of research questions. As an unfortunate consequence, it now suffers from substantial confusion about what ‘animal personality’ is, and how relevant related research frameworks are. Here, we stress the current inconsistencies and sources of confusion pertaining to the field, and their consequences on terminology used and miscommunication between researchers. In an attempt to unravel and clarify the concepts underlying the field, we identify two distinct, but complementary, theory‐driven conceptual frameworks: the intra‐individual variability (IIV) approach and the life‐history (LH) approach, which we believe encompass the vast majority of existing ‘personality studies’. Finally, we argue in favour of theory‐driven studies of consistent behavioural differences and state that the integrative statistical properties of random regression models should not override the merit of alternative conceptual frameworks. We then provide brief guidelines and warnings for a parsimonious and sound use of terminology.     

Light measurement and the terminology of low

Abstract. This paper (i) considers the measurement of light in terms of the flow of radiant energy or of particles in a vector field; (ii) derives terminology and units for the specification of light as a flow of radiant energy or of photons which satisfy both the requirements of SI and are physically consistent and (iii) recommends that this terminology is adopted by all plant scientists to avoid ambiguity, confusion and the proliferation of synonyms when reporting light measurements.     

Integrating animal temperament within ecology and evolution

Temperament describes the idea that individual behavioural differences are repeatable over time and across situations. This common phenomenon covers numerous traits, such as aggressiveness, avoidance of novelty, willingness to take risks, exploration, and sociality. The study of temperament is central to animal psychology, behavioural genetics, pharmacology, and animal husbandry, but relatively few studies have examined the ecology and evolution of temperament traits. This situation is surprising, given that temperament is likely to exert an important influence on many aspects of animal ecology and evolution, and that individual variation in temperament appears to be pervasive amongst animal species. Possible explanations for this neglect of temperament include a perceived irrelevance, an insufficient understanding of the link between temperament traits and fitness, and a lack of coherence in terminology with similar traits often given different names, or different traits given the same name. We propose that temperament can and should be studied within an evolutionary ecology framework and provide a terminology that could be used as a working tool for ecological studies of temperament. Our terminology includes five major temperament trait categories: shyness-boldness, exploration-avoidance, activity, sociability and aggressiveness. This terminology does not make inferences regarding underlying dispositions or psychological processes, which may have restrained ecologists and evolutionary biologists from working on these traits. We present extensive literature reviews that demonstrate that temperament traits are heritable, and linked to fitness and to several other traits of importance to ecology and evolution. Furthermore, we describe ecologically relevant measurement methods and point to several ecological and evolutionary topics that would benefit from considering temperament, such as phenotypic plasticity, conservation biology, population sampling, and invasion biology.