"恐龙"中文名称初考

在我国的科普书籍中,一般都说,“恐龙”一词是早年由我国的地质古生物工作者从拉丁文dinosaurus翻译成中文的。Dinosaurus一词原为英国古生物学家理查德·欧文于1842年所创,系“恐怖的蜥蜴”之意,其中并无“龙”的意思。但中文译者将其翻成“恐龙”而不是翻成“恐怖的蜥蜴”,其     

"发酵现象"实验的拓展

"发酵现象"是人教版《生物学》8年级上的"人类对细菌和真菌的利用"一节的演示实验,按照书上的要求只是观察现象并没有深入的探究,经过课堂实践,笔者把这个实验改为"探究酵母菌发酵作用产生了什么?"     

活化"三点"、"五艺"提高生物学课堂教学效率

结合课堂教学常规的"三点"、"五艺",加强生物学课堂教学改革,既是提高课堂教学效率的重要途径,同时也适合当前素质教育发展的需要.在教学过程中,只要我们妥善地把"三点"、"五艺"渗透到教学的各个环节,注意"三点"到位,强调点点明确,力求"五艺"形式灵活、多样,其课堂教学效果肯定事半功倍.     

中国苔藓植物濒危等级的评估原则和评估结果

本文阐述了中国苔藓植物濒危等级的评估原则。这一原则主要参考"IUCN物种红色名录濒危等级和标准(3.1版)",同时也吸收了其他苔藓学家的评估指南和结果。作者将10年内发表的新分类群暂评为数据缺乏(DD)等级,根据馆藏标本份数估计栖息地物种成熟个体数。在此基础上,对3,221个中国苔藓植物分类群进行评估,结果为:极危(CR)16种;濒危(EN)58种;易危(VU)112种;近危(NT)214种;无危(LC)1,900种;数据缺乏(DD)921种。极危、濒危和易危等级的受威胁苔藓植物合计186种,占中国苔藓植物种数的5.77%。     

真核基因转录调控因子的研究

生物的遗传信息全都编写在DNA分子上。在进行基因表达时,基因首先被转录成mRNA,然后翻译成蛋白质。这是生物学中最基本的规律。正是在这个规律基础上,把从微生物到人的各类生物统一成为一个大的生物系统。     

tRNA的结构、功能及合成简介

DNA是遗传的物质基础.DNA分子中由4种碱基组成的不同的核苷酸的排列顺序携带着不同的遗传信息.DNA分子所储存的遗传信息,必须通过转录传递给信使RNA分子(mRNA),才能到达蛋白质合成的场所--核糖体.然后合成蛋白质的酶系再把mRNA所带来的信息翻译成蛋白质.     

遗传密码新技术——生物大分子到音乐的转换及实现及其机制

科学家发现,多种生物大分子的序列的随机性与音乐有着明显的相似性。于是科学家尝试着为DNA序列以及蛋白质序列定义与音乐的转换规则,并且能够通过变换转换的规则,实现多种多样的音乐风格。生物大分子到数字音乐的转换是一种艺术与生物科学的跨学科融合,它具有一定的创造性,给生物学的研究带来的丰富的乐趣以及新的思路,同时创造了独一无二的"大自然"的音乐。目前已有正在进行的研究,通过分析现有的材质结构,设计转换规则将它翻译成音乐,并通过研究、修改音乐片段从而制作出新结构的材质,使该材质具有独特的性质。本文设计了一种DNA与蛋白质分别翻译成数字音乐的规则,并通过学习数字音乐的语法和规则编码实现生物大分子到数字音乐的转换,同时介绍了该技术的发展前景。     

华南石灰岩地区苦苣苔科植物一新种——散序小花苣苔

该文报道了华南地区石灰岩地区苦苣苔科报春苣苔属(Primulina Hance)一新种——散序小花苣苔(Primulina effusa F.WenB.Pan),并对该新分类群的濒危现状进行了评估,认为根据现在已知的居群和所受威胁情况,可暂定为"极危"之级别。     

促性腺激素释放激素类似物对长臀(鱼危)脑垂体促性腺激素分泌的影响

采用离体灌流孵育技术和促性腺激素的放射免疫测定方法,对长臀(鱼危)(Cranoglanis bouderius)脑垂体碎片促性腺激素的分泌进行了研究.结果表明:持续的促性腺激素释放激素类似物(GnRH-A)能显著刺激退化期的长臀(鱼危)离体脑垂体碎片促性腺激素(GTH)的分泌,并且长臀(鱼危)脑垂体碎片对持续的GnRH-A刺激未表现出脱敏性,该结果与胡子鲇和鲇鱼相似,而与金鱼和鲤科鱼类不同;重复脉冲GnRH-A刺激对长臀(鱼危)脑垂体碎片GTH分泌具有促进作用,而且存在剂量依存关系,与鲇鱼和鲤科鱼类相类似.上述结果表明在长臀(鱼危)的人工繁殖中可以用持续高浓度GnRH-A刺激对长臀(鱼危)进行催熟和催产.     

长吻(鱼危)养殖群体与野生群体遗传多样性分析

长吻(鱼危)(Leiocassis longirostris)是中国土著珍稀鱼类。近年来, 由于江河水利工程、环境污染及人类生产活动已经对江河的渔业资源造成了难以逆转的破坏, 长吻(鱼危)的渔业资源已逐渐枯竭。目前, 长吻(鱼危)在四川、广东等地实现适度规模养殖。以四川眉山、湖北石首和安徽淮南3个人工养殖长吻(鱼危)群体及4个长江野生长吻(鱼危)群体(重庆段、武汉段、安庆段和南京段)为实验材料, 利用线粒体DNA (mtDNA)控制区序列作为分子标记对135个个体的遗传结构进行了分析。结果表明, 在790 bp 的同源序列中, 长吻(鱼危) 3个养殖种群共检测到变异位点27个, 占全部序列的3.42%, 66个个体共检测到18种单倍型; 在野生群体中, 69个个体共检测到35个变异位点和36个单倍型, 长吻(鱼危)野生群体平均单倍型多样性和平均核苷酸多样性(Hd=0.9736±0.0070, Pi=0.0087±0.0015)高于长吻(鱼危)养殖群体(Hd=0.8867±0.0013, Pi=0.0056±0.0013); 群体间的遗传分化水平较低(F_st值为0.0014—0.1125)。采用邻接法(NJ法)和统计简约原理对所有单倍型进行系统发育树和统计简约网状图的构建, 结果表明: 各群体内的个体均不能分别构成独立的分支, 而是相互交叉聚在一起。分析结果表明, 长吻(鱼危)养殖群体与野生群体之间的基因交流充分, 未出现遗传分化, 但相对长吻(鱼危)野生群体, 长吻(鱼危)养殖种群多态性偏低。     

Assessing extinction risk in the absence of species-level data: quantitative criteria for terrestrial ecosystems

The conservation of individual plant and animal species has been advanced greatly by the World Conservation Union’s (IUCN) development of objective, repeatable, and transparent criteria for assessing extinction risk, which explicitly separate the process of risk assessment from priority-setting. Here we present an analogous procedure for assessing the extinction risk of terrestrial ecosystems, which may complement traditional species-specific risk assessments, or may provide an alternative when only landscape-level data are available. We developed four quantitative risk criteria, derived primarily from remotely sensed spatial data, information on one of which must be available to permit classification. Using a naming system analogous to the present IUCN species-specific system, our four criteria were: (A) reduction of land cover and continuing threat, (B) rapid rate of land cover change, (C) increased fragmentation, and (D) highly restricted geographical distribution. We applied these criteria to five ecosystems covering a range of spatial and temporal scales, regions of the world, and ecosystem types, and found that Indonesian Borneo’s lowland tropical forests and the Brazilian Atlantic rainforest were Critically Endangered, while South Africa’s grasslands and Brazil’s Mato Grosso were Vulnerable. Furthermore, at a finer grain of analysis, one region of Venezuela’s coastal dry forests (Margarita Island) qualified as Vulnerable, while another (the Guasare River watershed) was Critically Endangered. In northern Venezuela, deciduous forests were classified as Endangered, semi-deciduous forests Vulnerable, and evergreen forests of Least Concern. We conclude that adoption of such a standardized system will facilitate globally comparable, repeatable geographic analyses that clearly separate risk assessment (a fundamentally scientific process), from the definition of conservation priorities, which should take into account additional factors, such as ecological distinctiveness, costs, logistics, likelihood of success, and societal preferences. Jon Paul Rodríguez and Jennifer K. Balch are contributed equally to this work     

Phylogenetic Patterns of Extinction Risk in the Eastern Arc Ecosystems,an African Biodiversity Hotspot

There is an urgent need to reduce drastically the rate at which biodiversity is declining worldwide. Phylogenetic methods are increasingly being recognised as providing a useful framework for predicting future losses, and guiding efforts for pre-emptive conservation actions. In this study, we used a reconstructed phylogenetic tree of angiosperm species of the Eastern Arc Mountains – an important African biodiversity hotspot – and described the distribution of extinction risk across taxonomic ranks and phylogeny. We provide evidence for both taxonomic and phylogenetic selectivity in extinction risk. However, we found that selectivity varies with IUCN extinction risk category. Vulnerable species are more closely related than expected by chance, whereas endangered and critically endangered species are not significantly clustered on the phylogeny. We suggest that the general observation for taxonomic and phylogenetic selectivity (i.e. phylogenetic signal, the tendency of closely related species to share similar traits) in extinction risks is therefore largely driven by vulnerable species, and not necessarily the most highly threatened. We also used information on altitudinal distribution and climate to generate a predictive model of at-risk species richness, and found that greater threatened species richness is found at higher altitude, allowing for more informed conservation decision making. Our results indicate that evolutionary history can help predict plant susceptibility to extinction threats in the hyper-diverse but woefully-understudied Eastern Arc Mountains, and illustrate the contribution of phylogenetic approaches in conserving African floristic biodiversity where detailed ecological and evolutionary data are often lacking.     

Principal Drivers and Conservation Solutions to the Impending Primate Extinction Crisis: Introduction to the Special Issue

International Journal of Primatology - Nonhuman primates are facing an impending extinction crisis with over 65% of species listed as Vulnerable, Endangered, or Critically Endangered, and 93%...     

SOME RESULTS OF BIRD-BANDING IN THE CONGO (KINSHASA)

The global Blue Swallow Hirundo atrocaerulea was classified as Vulnerable in 2010 on account of its small and rapidly declining population estimated at less than 1 500 pairs. We undertook this study to gain a better understanding of the current status and threats facing this migratory species. Three previously unknown areas that might be part of the species' non-breeding range were identified in Kenya and northern Tanzania. Within its breeding range we identified three previously unknown areas of potentially suitable habitat, one in Tanzania and two in Malawi, which require further exploration. Population viability assessment predicted that the Blue Swallow population will decline by 8% in 10 years. The overall probability of extinction of the species in the wild is 3%. Minimum viable population size analysis suggests that a goal for the long-term conservation of the Blue Swallow should be to mitigate current threats that are driving declines such that the population increases to a minimum of 3 600 individuals. This should consist of at least 900 individuals in each of the four clusters identified, along with a minimum of 500 individuals in at least one of the meta-populations per cluster. The four clusters are located in (1) the southeasten Democratic Republic of the Congo, (2) highlands of southern Tanzania and northern Malawi, (3) eastern highlands of Zimbabwe and (4) South Africa and Swaziland. The current proportions of the Blue Swallow population in strictly protected and unprotected areas on their breeding grounds are 53% and 47%, respectively, whereas on their non-breeding grounds the corresponding percentages are 25% and 75%, respectively. Our reassessment of the Blue Swallow's risk of extinction indicates that it continues to qualify as Vulnerable according to the IUCN/SSC criteria C2a(i).     

Don’t let me down: West Indian manatee,Trichechus manatus,is still critically endangered in Brazil

Sirenians have a unique ecological function in coastal ecosystems, deserving special conservation attention. The West Indian manatee (Trichechus manatus) is globally classified as Vulnerable by the IUCN. In Brazil, where the species was intensively hunted in the past and currently faces several threats, it was classified as Endangered during the last national assessment published in 2014. Here, we generated information based on available data to assess the species extinction risk in Brazil using IUCN regional guidelines, applying all criteria, and choosing the highest category of risk. Abundance at the national level was projected considering the density estimated in Ceará and Rio Grande do Norte states and the Criterion B EOO (Extent of Occurrence) estimated in this study (34,899 km²) and resulted in 1,047 individuals (95% CI: 538–2,038). Six scenarios of annual mortality were inferred and suspected based on evidence. We adopted a simple discrete logistic growth model to project population reduction in the past and future (three generations − 69 years) in 18 scenarios. Among the 18 projected scenarios, four resulted in extinction, six in decline and eight in population growth. Considering the low abundance bound, all scenarios indicate a reduction larger than 80% in population size, classifying the species as ‘Critically Endangered’ based on A4de. Reduction in EOO and abundance in the past classify the species as ‘Endangered’ based on A2c. The suspected number of mature animals (607;95% CI: 312–1,182) and the projected decline higher than 20% in two generations also classify the species as ‘Endangered’ based on C1 and ‘Vulnerable’ under D1. Our results indicate that information can be generated to produce more accurate assessments based on available data. The species national extinction risk needs to be reassessed, and the National Action Plan effectiveness evaluated.     

Viability in a pink environment: why "white noise" models can be dangerous

Analysis of long time series suggests that environmental fluctuations may be accurately represented by 1/ f   noise (pink noise), where temporal correlation is found at several scales, and the range of fluctuations increases over time. Previous studies on the effects of coloured noise on population dynamics used first or second order autoregressive noise. I examined the importance of coloured noise for extinction risk using true 1/ f   noise. I also considered the problem of estimating extinction risk with a limited sample of environmental variation. Pink noise environments increased extinction risk in random walk models where environmental variation affected the growth rate. However, pink noise environments decreased extinction risk in the Ricker model where environmental variation modified the carrying capacity. Underestimation of environmental variance almost always yielded underestimation of extinction risk. For either population viability analysis or management, we should carefully consider the long-term behaviour of the environment as well as how we include environmental noise in population models.     

Long-term differences in extinction risk among the seven forms of rarity

Rarity is widely used to predict the vulnerability of species to extinction. Species can be rare in markedly different ways, but the relative impacts of these different forms of rarity on extinction risk are poorly known and cannot be determined through observations of species that are not yet extinct. The fossil record provides a valuable archive with which we can directly determine which aspects of rarity lead to the greatest risk. Previous palaeontological analyses confirm that rarity is associated with extinction risk, but the relative contributions of different types of rarity to extinction risk remain unknown because their impacts have never been examined simultaneously. Here, we analyse a global database of fossil marine animals spanning the past 500 million years, examining differential extinction with respect to multiple rarity types within each geological stage. We observe systematic differences in extinction risk over time among marine genera classified according to their rarity. Geographic range played a primary role in determining extinction, and habitat breadth a secondary role, whereas local abundance had little effect. These results suggest that current reductions in geographic range size will lead to pronounced increases in long-term extinction risk even if local populations are relatively large at present.     

Unravelling the structure of species extinction risk for predictive conservation science

Extinction risk varies across species and space owing to the combined and interactive effects of ecology/life history and geography. For predictive conservation science to be effective, large datasets and integrative models that quantify the relative importance of potential factors and separate rapidly changing from relatively static threat drivers are urgently required. Here, we integrate and map in space the relative and joint effects of key correlates of The International Union for Conservation of Nature-assessed extinction risk for 8700 living birds. Extinction risk varies significantly with species' broad-scale environmental niche, geographical range size, and life-history and ecological traits such as body size, developmental mode, primary diet and foraging height. Even at this broad scale, simple quantifications of past human encroachment across species' ranges emerge as key in predicting extinction risk, supporting the use of land-cover change projections for estimating future threat in an integrative setting. A final joint model explains much of the interspecific variation in extinction risk and provides a remarkably strong prediction of its observed global geography. Our approach unravels the species-level structure underlying geographical gradients in extinction risk and offers a means of disentangling static from changing components of current and future threat. This reconciliation of intrinsic and extrinsic, and of past and future extinction risk factors may offer a critical step towards a more continuous, forward-looking assessment of species' threat status based on geographically explicit environmental change projections, potentially advancing global predictive conservation science.     

Application of the IUCN Red Listing system to setting species targets for conservation planning purposes

Biodiversity targets, or estimates of the quantities of biodiversity features that should be conserved in a region, are fundamental to systematic conservation planning. We propose that targets for species should be based on the quantitative thresholds developed for the Vulnerable category of the IUCN Red List system, thereby avoiding future listings of species in an IUCN Red List threat category or an increase in the extinction risk, or ultimate extinction, of species already listed as threatened. Examples of this approach are presented for case studies from South Africa, including threatened taxa listed under the IUCN Red List criteria of A to D, a species listed as Near Threatened, a species of conservation concern due to its rarity, and one species in need of recovery. The method gives rise to multiple representation targets, an improvement on the often used single representation targets that are inadequate for long term maintenance of biodiversity or the arbitrary multiple representation and percentage targets that are sometimes adopted. Through the implementation of the resulting conservation plan, these targets will ensure that the conservation status of threatened species do not worsen over time by qualifying for higher categories of threat and may actually improve their conservation status by eliminating the threat of habitat loss and stabilizing population declines. The positive attributes ascribed to the IUCN Red List system, and therefore to the species targets arising from this approach, are important when justifying decisions that limit land uses known to be detrimental to biodiversity.