New approaches to restructuring school biology

Two structuring principles are discussed which both drop the old ‘systematic’ (taxonomic as well as subdiscipline-bound) way of structuring biological subject matter. They lead to a biology curriculum with great social and inter-disciplinary impact.     

采用偏最小二乘回归方法估测森林郁闭度

以遥感数据与森林资源一类清查数据为基础,探讨了用Bootstrap方法筛选最优郁闭度估测变量,用偏最小二乘回归方法建立模型估测森林郁闭度的可行性.结果表明：无论是用所有变量构造的模型还是用所选最优变量构造的模型,郁闭度估测的相对偏差在5%左右.筛选出的最优变量与其他地区的研究结论差异很大,说明除了筛选方法,地带性植被和地形地貌的不同也会造成估测郁闭度最优变量的差异.     

"生态环境"内涵界定探讨

“生态环境”是在中国使用频率较高的一个名词,由于一直没有明确而公认的定义,使用者往往误用,不利于今后理论研究和实践工作。本文追溯了生态环境概念的起源,对比分析了“生态环境”内涵的不同理解,基于生态学、环境科学理论,认为生态环境是以特定生物体(包括人类)为中心,多元复合生态系统各要素和生态关系的总和,强调生态系统的整体性、连续性、稳定性和协同进化性,以及在此基础上对主体提供的环境功能。     

An ecological approach to biosystem thermodynamics

The general attributes of ecosystems are examined and a naturally occurring reference ecosystem is established, comparable with the isolated system of classical thermodynamics. Such an autonomous system with a stable, periodic input of energy is shown to assume certain structural characteristics that have an identifiable thermodynamic basis. Individual species tend to assume a state of least dissipation; this is most clearly evident in the dominant species (the species with the best integration of energy acquisition and conservation). It is concluded that ecosystem structure results from the antagonistic interaction of two nearly equal forces. These forces have their origin in the Principle of Most Action (least dissipation or least entropy production) and the universal Principle of Least Action. Most action is contingent on the equipartitioning of the energy available, through uniform interaction of similar individuals. The trend to Least action is contingent on increased dissipation attained through increasing diversity and increasing complexity. These principles exhibit a basic asymmetry. Given the operation of these opposing principles over evolutionary time, it is argued that ecosystems originated in the vicinity of thermodynamic equilibrium through the resonant amplification of reversible fluctuations. On account of the basic asymmetry the system was able to evolve away from thermodynamic equilibrium provided that it remained within the vicinity of ergodynamic equilibrium (equilibrium maintained by internal work, where the opposing forces are equal and opposite).At the highest level of generalization there appear to be three principles operating: i) maximum association of free-energy and materials; ii) energy conservation (deceleration of the energy flow) through symmetric interaction and increased homogeneity; and iii) the principle of least action which induces acceleration of the energy flow through asymmetrical interaction. The opposition and asymmetry of the two forces give rise to natural selection and evolution.     

关于生态重建和生态恢复的思辨及其科学涵义与发展途径

Ecological restoration是现代生态学最活跃的关键行动之一, 在我国被译为“生态恢复”。经查验其英语涵义和演变过程, 建议正名为“生态重建”, 指在人为辅助下的生态活动。而“生态恢复”(recovery)在国际文献中指没有人直接干预的自然发生过程, 二者不容混淆。作者强调自然恢复和生态重建的三类时间尺度, 即地质年代尺度(千、万、亿年)自然生态系统世代交替和演替尺度(十、百、千年)和生态建设时间尺度(一、十、百年)。前二者为自然恢复尺度。三者相差2-3个数量级或更多。人类不能超尺度地依赖自然恢复能力, 自然与人为时间尺度的不匹配是自然恢复难以满足人类社会生态需求的根本原因。作者质疑“以自然恢复为主”和“从人工建设转向自然恢复为主的转变”提法。认为把生态重建的责任推诿给自然去旷日持久地恢复, 是不负责任和不作为的逻辑和有悖于“谁破坏, 谁补偿; 谁污染, 谁治理; 谁享用, 谁埋单”的全球环保公理和生态伦理观念。除恢复重建自然的生态系统外, 还要发展人工设计生态方案等未来生态重建途径。     

An ecological approach to birdstrike risk analysis

Airports are peculiar developed habitats that, besides being extremely noisy and unappealing to some bird species, are highly attractive to others. Bird–aircraft collisions, or birdstrikes, cause losses in terms of human lives, direct monetary losses and associated costs for the civil aviation industry. In recent years, birdstrike risk assessment studies have focused on the economical aspects of the damage caused by wild animals and the hazards of wildlife–aircraft collisions, while an ecological approach, taking into account animal behaviour for the analysis of such events, has seldom been adopted. We conducted a risk analysis for birdstrikes at the Venice Marco Polo International Airport (VCE), Italy. We defined the key variables involved in these events and summarised their interactions in a single metric risk index we called the “Birdstrike Risk Index” (BRI). Our aim was to provide a tool for birdstrike risk analysis that described the risk on the basis of the actual presence of birds at airports. The application of the BRI at VCE allows relative risks across species to be defined, providing information for prioritising management actions. Furthermore, due to the seasonality of bird species presences, the application of the BRI to a long-term data series should give clues of birdstrike risk in future scenarios. This new ecological approach that we applied to a particular airport could easily be adapted for use at other airports worldwide and integrated into risk assessment procedures. The study results and the BRI tool are addressed to scientific consultants of airport safety managers.     

Legitimation code theory to facilitate transition from high school to first-year biology

Institutions of Higher Education have grappled with the predicament of first-year success and epistemological access for years. Recently, a study employed Legitimation Code Theory (LCT) to elucidate why students who performed relatively well in high school biology struggled with the subject in first-year. This study shed valuable light on this problem by revealing that the high school biology curriculum is at a completely different level to the university curriculum. In terms of LCT’s Semantics dimension, the high school curriculum displayed little movement from context dependent simpler meanings towards the relatively decontextualised complex meanings, frequently encountered in first-year biology. We argue that the Semantics dimension of LCT also offers a useful tool for restructuring first-year biology curricula to intentionally facilitate a more gradual transition for first-year students. Thus, by explicitly planning teaching activities to gradually increase the range between context dependent simpler meanings and relatively decontextualized complex meanings, the potential of cumulative learning can be optimised. This paper reflects on the process of revising a first-year biology curriculum to contribute to greater epistemological access and cumulative knowledge building.     

An ecological approach to assessing the epidemiology of antimicrobial resistance in animal and human populations

We examined long-term surveillance data on antimicrobial resistance (AMR) in Salmonella Typhimurium DT104 (DT104) isolates from concurrently sampled and sympatric human and animal populations in Scotland. Using novel ecological and epidemiological approaches to examine diversity, and phenotypic and temporal relatedness of the resistance profiles, we assessed the more probable source of resistance of these two populations. The ecological diversity of AMR phenotypes was significantly greater in human isolates than in animal isolates, at the resolution of both sample and population. Of 5200 isolates, there were 65 resistance phenotypes, 13 unique to animals, 30 unique to humans and 22 were common to both. Of these 22, 11 were identified first in the human isolates, whereas only five were identified first in the animal isolates. We conclude that, while ecologically connected, animals and humans have distinguishable DT104 communities, differing in prevalence, linkage and diversity. Furthermore, we infer that the sympatric animal population is unlikely to be the major source of resistance diversity for humans. This suggests that current policy emphasis on restricting antimicrobial use in domestic animals may be overly simplistic. While these conclusions pertain to DT104 in Scotland, this approach could be applied to AMR in other bacteria-host ecosystems.     

多方位教学模式在植物生物学及实验教学中的探索北大核心CSCD

植物生物学是生物科学专业的专业基础课程。在发育生物学思想的指导下我们已构建了全面、系统、动态的植物生物学新教学体系。针对目前课程教学模式中存在的实体课堂教学模式单一、传授式教学学生听课不认真,理论课和实验课在内容和时间上的不匹配,野外实习时间短、认识植物片面、难以学以致用等问题,作者进行了教学模式改革和实践,提出了适合生物科学专业的教学新策略:实体课堂讲授与精品慕课(massive open online courses, MOOC)相结合,增加翻转课堂;理论课与实验课相结合,边讲边看;利用校园和植物园分别在早春、初夏和夏秋进行多次植物认知实习,野外实习中关注不同生境下的植物类型及其适应环境的特点。经两轮的教学实践表明,改革后在理论教学中提高了学生的学习兴趣,在实验教学中加强了能力训练,在认知实习中让学生对植物有了全面认识。该教学模式满足了素质教育的要求,进一步提高了植物生物学教学的质量,为学生后续学习其他基础课程和专业课程奠定基础。     

Enhancing theoretical understanding of a practical biology course using active and self-directed learning strategies

Laboratories are recognised as central in science education, allowing students to consolidate knowledge and master practical skills, however, their effectiveness has been questioned. Whilst laboratory practicals are useful for students’ learning of basic procedures, they have been shown to be less effective for developing conceptual understanding of the subject. Interactive lectures and bespoke digital resources were utilised in order to enhance theoretical understanding of laboratory practical molecular sessions, thus enabling students to take responsibility for and direct their own learning, encouraging inquiry-based learning. Providing easy to access additional learning resources offered students an opportunity to better prepare themselves for the laboratory, and consolidate their knowledge through subsequent review and self-testing in their own time. Grades before and after implementation of these active learning strategies were analysed to look at the impact on student learning and this study demonstrates that integrating these into a challenging practical biology course improved grades significantly with a concomitant increase in the number of ‘A’ grades attained. Feedback to evaluate use and perceptions of both interactive lectures and digital resources were also analysed. It has been shown here that these activities enhanced student experience and understanding of the course.     

景感生态学:生态安全研究与实践的重要途径

景感生态学是指以可持续发展为目标,基于生态学的基本原理,将自然要素、物理感知、心理感知、社会经济、过程与风险等相关因素综合考虑,来研究土地利用规划、建设与管理的科学。不合理的资源和土地开发利用活动常常会带来各种生态风险,从而导致生态安全方面的问题;而景感生态学的主要研究内容涉及土地利用,其目标是与可持续发展相关的人类愿景和社会需求。在追求的目标、遵循的原理、研究尺度及内容上,景感生态学与生态安全研究有许多契合的地方,有必要将景感生态学研究与生态安全研究结合起来。在简要解析生态安全内涵及其主要特点的基础上,探讨了如何将景感生态学思想与方法应用于生态安全研究,重点说明了作为景感生态学主要研究手段的趋善化模型、迷码数据以及物联网如何在生态安全研究中应用于数据获取、评价与预警、以及趋善化模型的构建。随着景感生态学研究的深入,其关注点可以从土地规划和利用扩展到生态安全格局构建与维护,从而更好地将人的愿景及福利与土地利用、生境质量和生态安全结合起来,为区域可持续发展提供科学参考。     

神木市生态安全格局构建与生态问题定量诊断

黄河流域生态保护和高质量发展是重大的国家战略,县域生态安全格局构建与生态问题定量诊断是实施生态保护修复的最基本单元。以神木市为研究对象,首先,基于电路理论构建神木市生态安全格局,将识别出的生态夹点、生态障碍点和低质量生态空间作为生态修复关键区域;其次,通过构建生态问题指标体系,在生态修复关键区域内定量化诊断现存生态问题;最后,通过生态问题指数(EPI)测算结果划定生态修复分区。研究表明：(1)神木市生态源地面积为411.64km²,以草地为主,主要分布在中部、东部和南部地区,源间生态廊道共63条,总长度约610.71km,中部地区的生态廊道较东南部密度大。(2)基于生态安全格局识别的生态修复关键区域包括生态夹点415个,面积达30.55km²;生态障碍点341个,面积共计25.72km²;低质量生态空间面积为1043.73km²。(3)生态修复关键区域内土壤侵蚀主要以微度侵蚀为主;地质灾害多发于采矿区以及黄土丘陵沟壑区;水源涵养低值区主要分布在低质量生态空间;林地和草地的退化程度呈现东部较中部和西南...     

流程化的生态建模方法与科学工作流系统

科学工作流系统是由一系列经过特殊设计的数据分析与管理步骤组成的、按照一定的逻辑组织在一起, 并在给定的运行环境下, 完成特定科学研究的工作流管理系统。科学工作流系统致力于使全世界的科学家可以在一个简单易用的平台上交换思想, 共同设计全球尺度的实验, 共享数据、实验步骤与结果等。每一个科学家可以独立创建自己的工作流, 执行工作流并实时查看结果; 不同科学家之间也可以方便地共享和复用这些工作流。本文以开普勒系统(Kepler system)和生物多样性虚拟实验室(BioVeL)两个项目为例, 介绍了科学工作流的发展历史、背景、现有项目和应用等。以生态位模型工作流为例, 介绍了科学工作流的流程以及特点等。并通过对现有科学工作流的分析, 对其发展方向和存在的问题提出了自己的看法及预期。     

基于Apache Spark机器学习的生态安全格局构建方法

区域生态安全格局构建往往是通过对各类环境因子不同层次、不同深度的分析以生成规划结果,少有学者直接对生态安全格局与环境因子之间的关系进行分析,研究通用模型。利用大数据计算框架Apache Spark机器学习库的Logistic Regression(LR)模型对佛山市高明、三水和顺德区已有生态安全格局规划数据与岩性、土壤、用地类型、NDVI、海拔、坡度、道路距离、河流距离、年均降雨量、人口密度等多个变量的相互关系进行了训练学习,得到回归模型,用以预测广东省生态安全格局,结果显示:1)基于Spark-LR的保障生态安全格局模型(GSPM)精度达到90.58%,其预测的广东省保障安全格局高概率区比例为50.56%,在实际应用中,有一定的参考价值;2)总体上GSPM预测的生态安全格局分布与已有规划类似,但是模型容易受到样点分布均匀性的影响;3)GSPM预测结果更加切合生态资源保护的需求,而常规方法构建的结果则需要进一步优化;4)Spark-LR机器学习对生态安全格局中城市扩张的预测具有一定的优势。     

茶树叶片净光合速率对生态因子的响应

试验以铁观音品种为材料 ,研究盆栽茶树叶片净光合速率对生态因子的响应。结果表明 :茶树叶片净光合速率 ( Pn)随着光合有效辐射 ( PAR)增加而迅速升高。成龄叶片光补偿点和光饱和点分别在 50～ 1 1 0 μmol/m2· s和 1 80 0～2 0 0 0 μmol/m2· s左右 ,光补偿点和光饱和点随叶龄、环境温度不同而异。茶树叶片净光合速率对叶温的响应曲线类似抛物线型 ,环境温度为 2 4℃和 2 7℃时光合最适温度分别为 2 7± 2℃和 3 0± 2℃。光合最适温度也随叶龄不同而不同。当空气 CO2 浓度在 2 90～ 3 60μl/L时 ,茶树叶片净光合速率 ( Pn)随空气 CO2 浓度提高而提高 ,但当浓度高于 3 70μl/L或低于2 80μl/L时 ,Pn的增大或减小都很急剧 ,CO2 补偿点在 2 83μl/L左右。茶树叶片净光合速率 ( Pn)随着土壤水势逐渐下降而下降 ,临时性萎蔫点在 -50 k Pa左右 ,永久性萎蔫点在 -62 k Pa左右 ,同时复胁迫茶树的抗旱性明显提高。     

An in vitro approach to ruminant mammary gland biology

This review discusses both fundamental and applied in vitro studies on ruminant mammary gland biology and summarizes progress made over the last decade in development of in vitro techniques to study growth, function and pathology of the mammary gland. The advantages and limitations of different in vitro systems are considered including explant cultures, primary cell cultures and immortalized lines of mammary-derived cells from cow, sheep and goat. The cell growth, differentiation and response to lactogenic hormones and growth factors are discussed as well as the relevance of the cell behavior in different culture conditions.