基于生物适应进化原理论证生物进化的动力

文章从现有主流生物进化理论存在的问题入手, 以生物适应进化原理为认识基础, 讨论生物进化的动力, 以求对生物进化机制有一个新的认识。在薛定谔“生命赖负熵生存”观点的指导下, 提出了“负熵流”包括能量流、物质流和信息流, 以及负熵流是生命生存和发育的动力的观点。作者在原有生物适应进化原理基础上, 修改完善并提出了“DNA、RNA和蛋白质在环境作用下的生物适应进化调控系统”理论, 并根据系统发育是个体发育的“积分”的观点, 推论得出生物与环境的负熵差引起的负熵流也是生命进化的动力, 对生物进化机制作出了新的理解。基于这样的生物进化机制的认识, 提出了“进化是一个子系统在其上一等级系统中, 将自身全部或部分信息遗传给下一代子系统, 并在其适应上一等级系统过程中, 产生一些新质, 终止一些旧质, 从而在其上一等级系统中得以延续的变化过程”的概念, 并探讨了一些与进化有关的其他争议问题。     

进化动力新探

许多学者,包括达尔文和杜布赞斯基等人对生物进化的原因颇有研究,伹对进化的动力问题论述甚少。然而,动力是生物进化的一种根本性的原因,是事物发展的内在根据。不搞清楚这个问题,就很难对生物的进化有更深刻的认识。关于生物进化的动力,流行的提法是遗传与变异(或称遗传与适应)之间的相互作用构成了生物进化的动力,它推动生物的进化,决定生物发展的方向和速度。其中,遗传是一种稳定性的因素,被认为是进化过程中保存物种的方面。由于生物有遗传性,谷子才成其为谷子,鸡才成其为鸡,人才成其为人。但是只遗传还不行,只遗传,原来有多少种生物,就永远是这么多生     

原始生物大分子动态的数学模型及其进化意义

本文应用生态学上关于种群增长及种间竞争的逻辑斯缔方程,提出原始生物大分子动态的数学模型,对从该模型推导得的几种可能结果进行了分析,得出在生命起源初期的原始生物圈的生物多样性是很低的结论,即原始生物圈中较大量存在的只是一些种类单一的,可复制的原始生物大分子,因此,可以认为生物进化就是建立在这样的一个基础上,并沿着生物多样性不断提高的途径演化,该模型还有助于对广泛存在于现代生物基因组中的重复序列的起源的认识。     

生物多样性与生态系统服务——关系、权衡与管理

生物多样性和生态系统服务是人类生存和社会经济可持续发展的物质基础,应对生物多样性丧失和生态系统服务退化问题已经成为继气候变化之后的又一个全球性环境热点问题。生物多样性是生态系统生产力、稳定性、抵抗生物入侵以及养分动态的主要决定因素,生物多样性越高,生态系统功能性状的范围越广,生态系统服务质量就越高越稳定。目的是探讨生物多样性和生态系统服务之间的关系:(1)明确了生物多样性与生态系统过程、功能、服务之间的关系;(2)生物多样性在生态系统服务中的角色:生物多样性在不同的空间尺度通过各种形式的运行机制与生态系统服务产生联系,生物多样性是生态系统过程的调节者,是巩固生态系统服务的一个重要因素,生物多样性也是一种终极的生态系统服务,并在遗传和物种水平上直接贡献了其利益和价值;(3)生物多样性与生态系统服务权衡和协同关系的研究可以更好的帮助管理人员做出有利的决策和保护工作,也是制定规划和适应策略以减少生物多样性危机带来的不利影响的基础;(4)生物多样性与生态系统服务的关系在不同的时间和空间尺度上是不恒定的,有必要共同确定生态系统服务和生物多样性的空间格局,以有效和可持续的进行生态系统管理;(5)虽然生物多样性保护和生态系统管理还存在许多不确定性,但相关理论应该在管理、保护和恢复生态系统中发挥重要作用。研究提出了进一步研究的领域,以促进生物多样性保护和生态系统服务提供之间的协同作用。希望对相关领域的研究有所帮助。     

昆虫嗅觉策略的进化

洛克菲勒大学和东京大学的研究人员发现,昆虫利用快速反应离子通道感知气味,这是一种完全不同于其他生物的嗅觉机制,也是生物进化领域的一大突破。达尔文生物进化树描绘了生物的进化路线,并可推测当代生物多样性的演化历程,而这项关于离子通道进化的结果有可能导致现有进化树的重构。     

湿地生物连通性影响因素及测度方法研究进展

湿地是地球上最多样化和最具生产力的生态系统之一,但近年来由于人类活动的频繁干扰,自然环境以前所未有的速度变化,两者的协同作用导致湿地呈现破碎化趋势。湿地的退化、转化使得湿地生物连通性减弱。良好的湿地生物连通性有利于湿地生态系统服务功能的维持、生物多样性的保护以及生物对气候变化适应水平的提高。因此理解、评估和保护生物连通性对于湿地生态系统而言至关重要。综述了湿地生物连通性的定义、总结了生物连通发生与变化的四个相互作用因子,从结构连通性、功能连通性两个测定角度,论述动物、植物和微生物三类研究对象生物连通性的测度方法,最后从湿地生物连通的时空尺度,连通与物质循环的耦合关系,湿地生物连通性评估分析模型改进角度提出了未来的研究方向,从而确保湿地生物连通网络的完整有效。可为湿地生物多样性、湿地保护和管理提供新的思路。     

生物多样性起源与进化研究进展

生物多样性的起源与进化是生命科学领域最重要的科学问题之一。多组学数据的积累和相关分析技术的发展, 极大地推动了人们对生物多样性起源与进化的理解和研究, 使得阐明生物进化事件发生的过程与机制成为可能。值此《生物多样性》创刊30周年之际, 本文简要回顾生物多样性起源与进化相关研究在近年来取得的重要研究进展, 以期帮助读者了解该研究方向的发展现状。过去10年中, 生物多样性起源与进化相关研究在生命之树重建、生物多样性时空分布格局、物种概念、物种形成与适应性进化以及新性状起源与多样化等方面取得了许多重要进展, 并在此基础上厘清了许多分类单元间的系统发育关系、揭示了生物多样性分布格局的部分历史成因、提出了新的物种概念和物种形成模型、阐明了新性状和新功能发生的部分分子机制。我们认为, 更精准地重建生命之树、深入挖掘基因组数据以及多学科交叉融合将是今后生物多样性研究的主要趋势。     

生态系统服务竞争与协同研究进展

生态系统服务作为生态系统评估的核心领域,是生态学的研究热点。生态系统提供服务的形式与能力受人类活动强烈影响,反之,生态系统服务的变化又影响着人类相关决策的制定。不同生态系统服务之间很难甚至不可能同时达到利益最大化,即存在着不同程度此消彼长的竞争关系。此外,不同生态系统服务之间也可能形成相互促进或抑制的协同作用。探讨不同生态系统服务的相互关系(竞争与协同作用),有利于揭示不同尺度利益相关方与生态系统服务之间的作用与反馈机制,避免生态系统服务的重复估算;同时可为制定与实施生态补偿、提高人类福祉提供科学依据,优化生态系统服务管理。综合研究了近期国外生态系统服务竞争关系与协同作用的相关文献,在简述当前生态系统服务研究若干问题的基础上,以生态系统服务竞争与协同为视角,厘清了生态系统服务竞争与协同的基本内涵,总结了生态系统服务竞争与协同的主要类型,探讨了生态系统服务竞争与协同的空间与时间尺度效应;介绍并总结了生态系统服务竞争与协同两种主要研究方法(生态-经济综合模型方法、基于土地利用的情景分析法)的特点与适应范围。     

分子进化研究中系统发生树的重建

在现代分子进化研究中,根据现有生物基因或物种多样性来重建生物的进化史是一个非常重要的问题。一个可靠的系统发生的推断,将揭示出有关生物进化过程的顺序,有助于我们了解生物进化的历史和进化机制。本文简要介绍了系统发生树推断的几个重要问题：建树方法、数据转换、树的可靠性及目前使用较多的几种分析软件。     

变异与进化

变异是生物进化的起步。生物进化的另一个重要内容是选择。生物进化的结果是产生出形形色色的生物类型及其对环境的各种适应。不言而喻,没有变异,就没有进化。种内变异已知遗传物质(主要是DNA)能准确地复制自己,这有助于我们了解生物的遗传。但是,遗传总不是绝对的。这是说,同一种生物之间总有些变异。一般说,后代是亲代的复制品或拷贝。从大处讲,无疑这是对的。可是这拷贝总不会是完全的。因此,我们能够认识我们的朋友。已知人的指纹没有两个人是完全相同的。从一个指纹就经常可以鉴別那是谁     

What do human economies,large islands and forest fragments reveal about the factors limiting ecosystem evolution?

What factors limit ecosystem evolution? Like human economies, ecosystems are arenas where agents compete for locally limiting resources. Like economies, but unlike genes, ecosystems are not units of selection. In both economies and ecosystems, productivity, diversity of occupations or species and intensity of competition presuppose interdependence among many different agents. In both, competitive dominants need abundant, varied resources, and many agents’ products or services, to support the activity and responsiveness needed to maintain dominance. Comparing different‐sized land masses suggests that productivity is lower on islands whose area is too small to maintain some of the interdependences that maintain diversity, productivity and competitiveness in mainland ecosystems. Islands lacking the rare, metabolically active dominants that make competition so intense in mainland ecosystems are more easily invaded by introduced exotics. Studies of islets in reservoirs identify mechanisms generating these phenomena. These phenomena suggest how continued fragmentation will affect future ‘natural’ ecosystems.     

关于蝗虫多样性与草原生态系统可持续发展的若干科学问题

蝗虫多样性既是草原生态系统演化的产物 ,反过来也影响着草原生态系统的结构与功能。蝗虫多样性状况与草原生态系统的持续发展有着密切的关联 ,这其中的科学问题包括 :(1 )蝗虫多样性及其空间变异机理 ;(2 )蝗虫多样性对草原生态系统过程的影响 ;(3 )蝗虫多样性空间格局与草原生态系统演化中的自然和人文因素的关联 ;(4 )蝗虫种群暴发的多样性阈值与草原生态系统的调控 ;(5 )蝗虫多样性和稳定性与草原生态系统的健康等。深入发掘生物多样性所包含的科学内涵 ,将一个物种的多样性与生态系统的结构和功能耦合起来研究 ,从重要物种蝗虫的生物多样性入手 ,深入探讨草原生态系统的持续发展问题 ,将为减少或减轻我国西部草原蝗灾发生提供科学的支持     

Evolution of larger sperm in response to experimentally increased sperm competition in Caenorhabditis elegans

Sperm morphology evolves rapidly, resulting in an exceptional diversity of sperm size and shape across animal phyla. This swift evolution has been thought to prevent fertilizations between closely related species. Alternatively, recent correlative analyses suggest that competition among sperm from more than one male may cause sperm diversity, but these hypotheses have not been tested. Here, we test experimentally the effect of sperm competition on sperm-size evolution using the nematode Caenorhabditis elegans. This worm has a three day generation time, which allowed the study to cover many generations. Sperm volume increased nearly 20% over 60 generations in lines genetically induced to have high levels of sperm competition compared with those of control lines. These results show that sperm competition can and does cause morphological evolution of sperm and, therefore, can explain much of the diversity in sperm morphology.     

Consequences of plant-herbivore coevolution on the dynamics and functioning of ecosystems

The potential consequences of plant-herbivore coevolution for ecosystem functioning are investigated using a simple nutrient-limited ecosystem model in which plant and herbivore traits are subject to adaptive dynamics. Although the ecological model is very simple and always reaches a stable equilibrium in the absence of evolution, coevolution can generate a great diversity of dynamical behaviors. The evolutionary dynamics can lead to a stable equilibrium. If the evolution of plants is fast enough, certain values of the trade-off parameters lead to complex evolutionary cycles bounded by physiological constraints. The dynamical behavior of the model is very different when the dynamics of inorganic nutrient is ignored and plant competition is modeled by a logistic growth function. This emphasizes the importance of including explicit nutrient dynamics in studies of plant-herbivore coevolution.     

Teasing apart plant community responses to N enrichment: the roles of resource limitation,competition and soil microbes

Although ecologists have documented the effects of nitrogen enrichment on productivity, diversity and species composition, we know little about the relative importance of the mechanisms driving these effects. We propose that distinct aspects of environmental change associated with N enrichment (resource limitation, asymmetric competition, and interactions with soil microbes) drive different aspects of plant response. We test this in greenhouse mesocosms, experimentally manipulating each factor across three ecosystems: tallgrass prairie, alpine tundra and desert grassland. We found that resource limitation controlled productivity responses to N enrichment in all systems. Asymmetric competition was responsible for diversity declines in two systems. Plant community composition was impacted by both asymmetric competition and altered soil microbes, with some contributions from resource limitation. Results suggest there may be generality in the mechanisms of plant community change with N enrichment. Understanding these links can help us better predict N response across a wide range of ecosystems.     

Evolution of phenotypic clusters through competition and local adaptation along an environmental gradient

We have analyzed the evolution of a quantitative trait in populations that are spatially extended along an environmental gradient, with gene flow between nearby locations. In the absence of competition, there is stabilizing selection toward a locally best-adapted trait that changes gradually along the gradient. According to traditional ideas, gradual spatial variation in environmental conditions is expected to lead to gradual variation in the evolved trait. A contrasting possibility is that the trait distribution instead breaks up into discrete clusters. Doebeli and Dieckmann (2003) argued that competition acting locally in trait space and geographical space can promote such clustering. We have investigated this possibility using deterministic population dynamics for asexual populations, analyzing our model numerically and through an analytical approximation. We examined how the evolution of clusters is affected by the shape of competition kernels, by the presence of Allee effects, and by the strength of gene flow along the gradient. For certain parameter ranges clustering was a robust outcome, and for other ranges there was no clustering. Our analysis shows that the shape of competition kernels is important for clustering: the sign structure of the Fourier transform of a competition kernel determines whether the kernel promotes clustering. Also, we found that Allee effects promote clustering, whereas gene flow can have a counteracting influence. In line with earlier findings, we could demonstrate that phenotypic clustering was favored by gradients of intermediate slope.     

Intransitive competition is widespread in plant communities and maintains their species richness

Intransitive competition networks, those in which there is no single best competitor, may ensure species coexistence. However, their frequency and importance in maintaining diversity in real‐world ecosystems remain unclear. We used two large data sets from drylands and agricultural grasslands to assess: (1) the generality of intransitive competition, (2) intransitivity–richness relationships and (3) effects of two major drivers of biodiversity loss (aridity and land‐use intensification) on intransitivity and species richness. Intransitive competition occurred in > 65% of sites and was associated with higher species richness. Intransitivity increased with aridity, partly buffering its negative effects on diversity, but was decreased by intensive land use, enhancing its negative effects on diversity. These contrasting responses likely arise because intransitivity is promoted by temporal heterogeneity, which is enhanced by aridity but may decline with land‐use intensity. We show that intransitivity is widespread in nature and increases diversity, but it can be lost with environmental homogenisation.     

Geophysiological modeling: new ideas on modeling the evolution of ecosystems.

Living organisms evolve within ecological associations (from ecosystems to the biosphere) that are constituted by a biological component and a physico-chemical component. It is generally supposed that interactions such as competition and predation between the biological components of ecosystems are the main cause for the observed organization of ecosystems. We believe that in the search for a more comprehensive theory of evolution a much greater attention should be paid to the ways in which living organisms interact with the physico-chemical environment. To test our ideas, we develop a mathematical model to study the evolution of ecosystems, and we apply it to the study of hydrothermal vents. The model proposed is still a qualitative model. It tries to study, in a first approximation, the behaviours of the biological and chemical components. In the following we hope to develop and to improve it so to give a more realistic model.     

Biotic resistance in marine environments

Biological invasions depend in part on the resistance of native communities. Meta‐analyses of terrestrial experiments demonstrate that native primary producers and herbivores generally resist invasions of primary producers, and that resistance through competition strengthens with native producer diversity. To test the generality of these findings, we conducted a meta‐analysis of marine experiments. We found that native marine producers generally failed to resist producer invasions through competition unless the native community was diverse, and this diversity effect was weaker in marine than in terrestrial systems. In contrast, native consumers equally resisted invasive producers in both ecosystems. Most marine experiments, however, tested invasive consumers and these invasions were resisted more strongly than were producer invasions. Given these differences between ecosystems and between marine trophic levels, we used a model‐selection approach to assess if factors other than the resistance mechanism (i.e. competition vs. consumption) are more important for predicting marine biotic resistance. These results suggest that understanding marine biotic resistance depends on latitude, habitat and invader taxon, in addition to distinguishing between competition with and consumption by native species. By examining biotic resistance within and across ecosystems, our work provides a more complete understanding of the factors that underlie biological invasions.     

AM真菌在草原生态系统中的功能

AM真菌是土壤生态系统中重要的微生物类群,能与陆地生态系统中80%以上的高等植物建立共生体系。目前,AM真菌在维持草原生态系统稳定性中的功能已经成为生态学研究的热点问题之一。基于此,从植物个体、种群、群落和生态系统等不同层次探究AM真菌在维持植物群落多样性和草原生态系统稳定性中的功能。分析发现在个体水平上,AM真菌对宿主植物具有促生效应、抑制效应或中性效应。在种群水平上,分析AM真菌对不同宿主植物吸收土壤矿质营养的分配和调控策略,围绕构成草原植被的两大组成成分:牧草和有毒植物,论述AM真菌对植物种群增长和衰败的调控机制,并从草原植物群落的物种多样性和稳定性角度,探讨AM真菌与植物群落之间的相关性。在生态系统水平上,围绕AM真菌对草原生态系统的演替和退化草原的修复等展开论述,以期为利用AM真菌开展草原生态系统保护和恢复治理提供理论依据,并对草原菌根生态学领域未来的研究进行展望。