昆虫内共生菌研究进展

昆虫体内栖息着丰富多样的微生物,这些微生物与昆虫的长期共同进化过程中形成了相互依存的共生关系。共生菌在宿主的营养获取、取食消化、免疫活动、逃避天敌、生长发育、繁殖中发挥着不可或缺的重要作用。尤其是共生菌——昆虫——植物互作关系,已经成为研究热点。本文从昆虫共生菌的种类、功能以及与宿主的互作机制等多方面进行描述。     

小芝麻告诉你——指示性植物

正1.某些种类的植物在漫长的进化过程中,为了更好地适应自然环境,形成了自身的"特异功能"——指示性。2.树木如果异乎寻常的茁壮,可能地下有锰矿;桧树发光,说明土壤含铝;发现了忍冬藤的树丛,几乎就是发现了一座银矿。3.已报道的指示植物有70余种,几乎都是草本植物,其中三分之一以上属于豆科、石竹科和唇形科。     

领导者和秘书在现实工作中角色互错现象分析

领导者和秘书是同一组织系统中有着不同的角色地位和角色人格的一对矛盾，有着领导与被领导、服务与被服务的工作关系。领导处于支配和主导地位，秘书处于从属和被支配的地位。他们有着共同的工作目标，他们在实现组织目标和过程中，责任和权力是不一样的，扮演着不同的角色，由于工作的相互渗透性和联系性常常发生角色互错现象,如领导者要么事无巨细，事必躬亲，越权替代秘书；要么过分依赖秘书，放弃领导权，秘书越权代替领导。     

中国荒漠地区野生动物生态学特征及管理对策

荒漠生态系统野生动物较其它自然生态系统种类少，单位面积生物量小荒漠生态系统野生动物中以啮齿类和羚羊类占优势。荒漠动物在长期进化过程中，在形态上，生理上，行为上有许多特点适应干旱的气候。由于荒漠生态系统非常脆弱。在遭受外界干扰情况下恢复力和抵抗力都很弱。     

农田杂草特性及防除效果

1农田杂草的特性 农田杂草来源主要有两个方面:一是长期适应于自然条件变化的野生草;二是随农业生产发展过程中而进化的新种类或变种.     

生态平衡

生态系统发展到成熟阶段时,它的结构功能,包括生物种类的组成、生物数量比例以及能量流动、物质循环都处于相对稳定状态,这就叫做生态平衡。 在一般情况下,成熟的生态系统内部物种越丰富,食物网就越复杂,物质循环和能量流动可以多     

黑伯劳(Lanius fuscatus)的分类地位研究

记录了黑伯劳（Lanius fuscatus）在江西的新分布区,对黑伯劳起源、进化及分类地位的确定均具有重要意义。分析了黑伯劳的分类地位,认为黑伯劳作为独立物种证据不足,推测黑伯劳可能是棕背伯劳这一祖型处于分化过程正在形成中的亚种或居群或种。建议从黑伯劳的分布、遗传等方面进行其分类地位的确定。     

寄生蜂28S rDNA D2 区序列及其分子系统学研究

对棉铃虫齿唇姬蜂Campoletis chlorideae Uchida、腰带长体茧蜂Macrocentrus cingulum Brischke和麦蚜茧蜂 Ephedrusplagia-tor（Nees）3种寄生蜂28S rDNA D2区序列进行了聚合酶链式反应（PCR）,检索了GenBank核酸序列库中姬蜂总科和小蜂总科的其它26种寄生蜂的相应序列,利用29种寄生蜂及2种弹尾目昆虫28S rDNA D2区序列对寄生蜂进行了系统进化分析.结果表明,3种寄生蜂28S rDNA D2区序列与同一亚科的其他种相似性达90%以上.3种寄生蜂中,腰带长体茧蜂和麦蚜茧蜂与弹尾目昆虫的遗传距离较远,是较进化的种类;棉铃虫齿唇姬蜂与弹尾目昆虫的遗传距离较近,是较早分化的种类.29种寄生蜂系统进化分析表明,茧蜂科的蚜茧蜂亚科和长体茧蜂亚科处于同一分化地位,但有明显分化;小蜂总科与姬蜂科处于同一分化地位,比茧蜂科分化晚.     

褐菖鲉和松江鲈侧线形态的比较

鱼类的侧线类型是由分类地位还是由环境的适应而定是进化形态学的关键问题之一。通过光镜和扫描电镜,首次描述和比较了同属鲉形目的褐菖鲉和松江鲈的侧线形态及其分布。研究结果显示,两种研究对象的侧线都仅具机械感觉系统,包括管道侧线和表面神经丘,但它们的形态及分布有差异。褐菖鲉头部管道属分枝型;松江鲈属简单型管道,比褐菖鲉有更多的表面神经丘。这两种鱼都属以管道为主,表面神经丘为辅助来感知水流动态的类型,但是,栖息在急流的褐菖鲉具有分枝型管道侧线和较少的表面神经丘分布;生活在缓流的松江鲈有简单型管道侧线和较多的表面神经丘分布,表明这些侧线的形态特征与不同栖息地水流环境关系密切。本文认为,分类地位接近的褐菖鲉和松江鲈侧线系统的形态区别,是其在进化过程中对不同栖息地水流特征的适应而形成。     

生物进化背景下人类的可持续发展(英文)

进化、适应和选择贯穿在任何一个物种的演化过程中,这是生物与环境相互联系、相互作用的结果,是大自然固有的运动规律在生物物种演化过程中的体现。只有准确地把握进化、适应和选择三者的内涵,以生物进化为主线,以人类可持续发展为中心,把人类对环境的主动适应和自然、社会对生物物种的方向性选择结合起来,从更深的层面上理解生物的进化和在生物进化背景下人类的可持续发展,才能在理论上和实践中坚持真正的达尔文主义和现代进化观及当代可持续发展观。     

进化的不可逆规律

进化的不可逆规律包括两个水平的内容:一是生物形态解剖结构进化的不可逆转,二是物种灭绝失传不可再生。进化不可逆性实质上是时间不可逆性在生物学上的反映,具体表现为突变的季莫维也夫—里绍夫斯基效应和遗传结构的缺失效应。进化的不可逆性不论有什么表现形式其唯一的本质就是生物遗传信息组织性持续不断地增长。     

DNA分子进化研究进展

分子进化和重组技术在蛋白质体外进化工程中占据着越来越重要的地位,它可以对单一基因、质粒、代谢途径、部分甚至整个基因组进行改造,从而在较短时间内获得漫长自然进化过程无法得到的具有特定性质的基因、蛋白质甚至物种。文章通过综合概括各种DNA分子进化技术的原理、特点,并介绍这些技术的应用研究进展以及最新研究方向,促进其在提高酶活性、蛋白质产量和改善蛋白质（酶）的性能等方面广泛应用。     

九寨沟自然保护区蔷薇科植物区系特征研究

在对九寨沟自然保护区蔷薇科植物详细调查的基础上,对其亚科、属、种组成、分布区类型、区系特征等进行了统计和分析。结果表明:1.区内有蔷薇科植物4亚科、20属、97种;2.区内蔷薇科植物与外界物种的交流相对较少,在演化中处在比较原始的阶段;3.优势属明显,植物区系具明显的温带性质;4.植物区系起源古老;5.该区处在苹果属的重要演化地带内。     

Humans as the world's greatest evolutionary force

In addition to altering global ecology, technology and human population growth also affect evolutionary trajectories, dramatically accelerating evolutionary change in other species, especially in commercially important, pest, and disease organisms. Such changes are apparent in antibiotic and human immunodeficiency virus (HIV) resistance to drugs, plant and insect resistance to pesticides, rapid changes in invasive species, life-history change in commercial fisheries, and pest adaptation to biological engineering products. This accelerated evolution costs at least $33 billion to $50 billion a year in the United States. Slowing and controlling arms races in disease and pest management have been successful in diverse ecological and economic systems, illustrating how applied evolutionary principles can help reduce the impact of humankind on evolution.     

Phenotypic plasticity in the interactions and evolution of species

When individuals of two species interact, they can adjust their phenotypes in response to their respective partner, be they antagonists or mutualists. The reciprocal phenotypic change between individuals of interacting species can reflect an evolutionary response to spatial and temporal variation in species interactions and ecologically result in the structuring of food chains. The evolution of adaptive phenotypic plasticity has led to the success of organisms in novel habitats, and potentially contributes to genetic differentiation and speciation. Taken together, phenotypic responses in species interactions represent modifications that can lead to reciprocal change in ecological time, altered community patterns, and expanded evolutionary potential of species.     

Orchestrated transcription of key pathways in Arabidopsis by the circadian clock

Like most organisms, plants have endogenous biological clocks that coordinate internal events with the external environment. We used high-density oligonucleotide microarrays to examine gene expression in Arabidopsis and found that 6% of the more than 8000 genes on the array exhibited circadian changes in steady-state messenger RNA levels. Clusters of circadian-regulated genes were found in pathways involved in plant responses to light and other key metabolic pathways. Computational analysis of cycling genes allowed the identification of a highly conserved promoter motif that we found to be required for circadian control of gene expression. Our study presents a comprehensive view of the temporal compartmentalization of physiological pathways by the circadian clock in a eukaryote.     

Mass Spawning by Green Algae on Coral Reefs

Predawn episodes of mass spawning by green algae (up to nine species in five genera on a single morning) intermittently cloud Caribbean waters. Species- and sex-specific bouts of anisogamous gamete release occurred synchronously and predictably on a given morning, with closely related species spawning at different times. Algal sexual reproduction was seasonal, but, unlike the mass-spawning behavior of other sessile marine organisms, showed no lunar or tidal cycling. The discovery of mass-spawning behavior by these algae has important implications for future studies of the reproductive ecology and speciation of a vital, yet poorly understood, component of the coral reef community.     

Casting a genetic light on the evolution of eyes

Light has been exploited for information by organisms through the evolution of photoreceptors and, ultimately, eyes in animals. Only a handful of eye types exist because the physics of light constrains photodetection. In the past few years, genetic tools have revealed several parallel pathways through which light guides behavior and have provided insights into the convergent evolution of eyes. The gene encoding opsin (the primary phototransduction protein) and some developmental genes had very early origins and were recruited repeatedly during eye evolution. Eye lens proteins arose separately and make up a diverse group, many of which were co-opted from other functions. A major challenge now is understanding how newly discovered pathways for processing light evolved and how they collaborate with eyes to harvest information from light.     

Complex species interactions and the dynamics of ecological systems: long-term experiments

Studies that combine experimental manipulations with long-term data collection reveal elaborate interactions among species that affect the structure and dynamics of ecosystems. Research programs in U.S. desert shrubland and pinyon-juniper woodland have shown that (i) complex dynamics of species populations reflect interactions with other organisms and fluctuating climate; (ii) genotype x environment interactions affect responses of species to environmental change; (iii) herbivore-resistance traits of dominant plant species and impacts of "keystone" animal species cascade through the system to affect many organisms and ecosystem processes; and (iv) some environmental perturbations can cause wholesale reorganization of ecosystems because they exceed the ecological tolerances of dominant or keystone species, whereas other changes may be buffered because of the compensatory dynamics of complementary species.