重演律与生物进化

重演律与生物进化杜近义（浙江教育学院,杭州３１００１２）（一）“重演律”亦称“生物发生律”。这主要是由德国生物学家、进化论者海克尔（ＥｒｎｓｔＨｅｉｎｒｉｃｈＨａｅｃｋｅｌ）根据动物形态学和胚胎学的研究成果于１８６６年提出来的一条定律。该定律主要涉及...     

不同脊椎动物骨骼肌的解剖结构与动物进化程度的关系

目的:依据发育重演律的理论,比较进化程度不同的脊椎动物骨骼肌是否存在结构层次的差异。方法:选取进化程度不同的脊椎动物,如哺乳动物、鸟类、两栖动物及鱼类,选择各类有代表性并容易取材的动物,通过苏木精伊红染色(HE染色)的方法对健康的昆明白小鼠、家兔、家鸽、牛蛙、鲫鱼背部及腿部肌肉横切面进行观察。结果:昆明白小鼠、家兔、家鸽、牛蛙、鲫鱼的骨骼肌都有相类似的层次结构,即每块骨骼肌由数个肌束构成,骨骼肌外被肌外膜,肌束由肌束膜包绕,每个肌束又由众多肌纤维构成,肌纤维由肌内膜包绕。骨骼肌的层次结构与动物的进化程度和实验取材部位无关。结论:表明进化程度不同的脊椎动物骨骼肌的进化程度相近。表明骨骼肌的3层结构并非在脊椎动物阶段进化完成的。     

从自然选择和遗传漂变理解生物进化

进化过程在生物学、医学、农学等领域发挥着越来越重要的作用。从基于自然选择过程的适应进化和遗传漂变主导的随机进化2个方面诠释进化的概念,即进化是生物世代间性状的改变。     

生物进化与特化

作者试图把生物的适应性变化区分成生物的进化和特化两种不同的概念,进化即生物逐渐演变,向前发展的过程;特化是指生物的水平发展的物种形成过程,即生物多样性的形成过程,这种区分可以避免许多不必要的争论,把这个新的概念体系和以往人们对生物进化研究的理论相结合。并用该方法重新解释以往人们的研究发现,可以看出生物发展的历史就是生物进化和特化交替进行的历史,以此可解释许多不同理论之间的矛盾。     

可动因子与生物进化

可动因子与生物进化李宏（渝州大学生物系,重庆,６３００３３）自从１９８３年,美国遗传学家ＭｃＣｌｉｎｔｏｃｋ在玉米籽粒的色斑遗传研究中发现了转座因子（ｔｒａｎｓｐｏｓｏｎ）以来,人们逐渐发现除了这种转座因子之外,还存在着另外一些能发生转座的因子,比如...     

铀与生物进化（续）

蜥蜴学飞行“原始爬行动物出现的时间为晚石炭世,即在沉积地层中铀和有机物增多之时。这样的地层发现于北美和世界上的其他地区。其特点是,在这一时期出现的蜥蜴,作为正常的陆生四足动物开始生存在地球上。然而在随其后的铀含量增多的时期,即在二叠纪与三叠纪分界时,地史上出现了最早的会飞的脊椎动物——翼龙。有趣的是,在翼龙的解剖构造上,与陆生爬行动物唯一的重要差异是多了一个旁边的第四指——“小指”。在所有的指骨当中,这个小指极度延长,几乎等于整个体长的两倍。从这个过分的长指上长出翼膜,形成飞行的脊椎动物的最早的翅膀。飞行脊椎动物出现的时间,不迟不早,恰好是在二叠纪与三叠纪分界处的放射性增强的地层中。这一情况促使人们想到,飞     

基因突变的分子机制与生物进化

在自然群体中发现的遗传变异和物种之间的差异是人们普遍熟知的。同时我们都知道,最原始的生命非常小而且简单,可现在却有     

重演律与生命起源

分子层次上的“发生律”在现代科学中,“生命起源”是最难以解答的“宇宙之谜”了,因为这已是三、四十亿年前的事。事过境迁,沧海桑田,那么漫长的岁月,任何蛛丝马迹都早已消逝在悠悠的历史长河之中了,要作出有根据的回顾,这又谈何容易!现在可能做的,只不过是在模拟实验中对当时的情景作一番大体追索,或者根据近代科学知识,在沉思冥想中把点滴资料联贯起来,勾画出一幅能够自圆其说的约略图案罢了。这样的图案,不用说,必然会是众说纷纭,颇多争议的。那么     

熵、生物进化与Brooks-Wiley理论

介绍了熵与生物进化两个概念间的辩证统一关系,重点讨论了Brooks-Wiley理论,该理论认为"生物进化是熵增加过程",同时又是复杂性、组织性和秩序性都不断增加的进程.     

模型分析在动物进化生物学研究中的应用

早期的生态学研究往往局限于对野外观察现象的基本描述。随着模型分析方法的引入,可以通过建立数学模型寻找描述性材料中蕴藏的一般性规律,探讨某一现象产生的原因及其制约因素。近年,随着计算机技术的飞速发展和普及,模型分析方法应用越来越广泛。动物行为的进化及其对环境的适应性一直以来都是生态学研究的热点,根据应用不同的理论基础,人们发展了许多不同的建模方法,主要包括种群遗传学模型、最优化模型、博弈模型、基于个体的模拟模型和系统发育对比分析模型等。本文主要介绍了以上5种模型方法,及其在动物进化生物学研究中的应用现状。     

Evolutionary Cell Biology of Proteins from Protists to Humans and Plants

During evolution, the cell as a fine‐tuned machine had to undergo permanent adjustments to match changes in its environment, while “closed for repair work” was not possible. Evolution from protists (protozoa and unicellular algae) to multicellular organisms may have occurred in basically two lineages, Unikonta and Bikonta, culminating in mammals and angiosperms (flowering plants), respectively. Unicellular models for unikont evolution are myxamoebae (Dictyostelium) and increasingly also choanoflagellates, whereas for bikonts, ciliates are preferred models. Information accumulating from combined molecular database search and experimental verification allows new insights into evolutionary diversification and maintenance of genes/proteins from protozoa on, eventually with orthologs in bacteria. However, proteins have rarely been followed up systematically for maintenance or change of function or intracellular localization, acquirement of new domains, partial deletion (e.g. of subunits), and refunctionalization, etc. These aspects are discussed in this review, envisaging “evolutionary cell biology.” Protozoan heritage is found for most important cellular structures and functions up to humans and flowering plants. Examples discussed include refunctionalization of voltage‐dependent Ca²⁺ channels in cilia and replacement by other types during evolution. Altogether components serving Ca²⁺ signaling are very flexible throughout evolution, calmodulin being a most conservative example, in contrast to calcineurin whose catalytic subunit is lost in plants, whereas both subunits are maintained up to mammals for complex functions (immune defense and learning). Domain structure of R‐type SNAREs differs in mono‐ and bikonta, as do Ca²⁺‐dependent protein kinases. Unprecedented selective expansion of the subunit a which connects multimeric base piece and head parts (V0, V1) of H⁺‐ATPase/pump may well reflect the intriguing vesicle trafficking system in ciliates, specifically in Paramecium. One of the most flexible proteins is centrin when its intracellular localization and function throughout evolution is traced. There are many more examples documenting evolutionary flexibility of translation products depending on requirements and potential for implantation within the actual cellular context at different levels of evolution. From estimates of gene and protein numbers per organism, it appears that much of the basic inventory of protozoan precursors could be transmitted to highest eukaryotic levels, with some losses and also with important additional “inventions.”     

Hierarchies and the Sloshing Bucket: Toward the Unification of Evolutionary Biology

Evolutionary biology presents a bewildering array of phenomena to scientists and students alike—ranging from molecules to species and ecosystems; and embracing 3.8 billion years of life’s history on earth. Biological systems are arranged hierarchically, with smaller units forming the components of larger systems. The evolutionary hierarchy, based on replication of genetic information and reproduction, is a complex of genes/organisms/demes/species and higher taxa. The ecological hierarchy, based on patterns of matter–energy transfer, is a complex of proteins/organisms/avatars/local ecosystems/regional ecosystems. All organisms are simultaneously parts of both hierarchical systems. Darwin’s original formulation of natural selection maps smoothly onto a diagram where the two hierarchical systems are placed side-by-side. The “sloshing bucket” theory of evolution emerges from empirical cases in biological history mapped onto this dual hierarchy scheme: little phenotypically discernible evolution occurs with minor ecological disturbance; conversely, greatest concentrations of change in evolutionary history follow mass extinctions, themselves based on physical perturbations of global extent. Most evolution occurs in intermediate-level regional “turnovers,” when species extinction leads to rapid evolution of new species. Hierarchy theory provides a way of integrating all fields of evolutionary biology into an easily understood—and taught—rubric.

Evolutionary adaptability of biological macromolecules

Summary The degree of gradualism with which tertiary structure and function of protein changes with stepwise changes in primary structure (assumed to be influenced by redundancy of weak bonding) is both a precondition for and consequence of evolution. The resulting selection for degree of gradualism has implications for a number of structural and functional properties of modern proteins as well as for the significance of neutral (so-called non-Darwinian) phenomena in relation to selection.     

分子进化生物学中序列分析方法的新进展

简要介绍了分子进化生物学中序列分析方法的最新进展,特别强调了似然比检验和贝叶斯推论在分子进化和系统发育假说检验中的重要性,并介绍了新方法的一些成功应用,同时还给出了一些重要的信息资源。