被子植物雌全同株性系统:系统演化、性表达与进化意义

雌全同株是指雌花和两性花共同发生在同一植株上的性表达形式。作为被子植物从雌雄同花(两性花)向雌雄同株异花进化的一个重要阶段,雌全同株性系统在减少昆虫对雌性的取食和伤害、提高异交率以减少近交衰退、减少雌/雄功能干扰、提高雌/雄性功能间资源分配的灵活性,以及吸引传粉者等方面具有重要的进化适应意义。根据APG III分类系统,雌全同株性系统在被子植物木兰分支(magnoliids)的短蕊花科、单子叶植物分支(monocots)的天南星科和禾本科,以及核心真双子叶植物分支(core eudicots)中的菊科、苋科、唇形科和石竹科等23科中均有报道,且以菊科植物中最多。雌全同株植物不同类群的雌花和两性花在位置、形态、大小及开花时间等性表达特征上表现出多样化,且这些特征不仅受遗传因子的调控,还受可获得资源(如营养、光照、温度和水分等条件)的制约。该文针对我国对雌全同株性系统的研究还相对较少的现状,重点对具雌全同株性系统的类群在被子植物中的分布与系统演化、性表达与环境的关系等方面进行了分析与总结,并对有关其进化适应意义的5个假说进行了介绍和评价,对今后的研究方向进行了展望,以期为推动我国对被子植物雌全同株性系统的进化式样与机制研究提供理论资料。     

生态系统和谐原理初探

论述了生态系统的时空结构特征、生命有机体为核心特征、物质循环作用、能量流动过程、信息交换网络等个别特征．自然界的和谐规律是生态系统运动过程中更加普遍意义上的规律．最后讨论了和谐规律在生态系统中的具体体现,并期望在今后的生态学研究中自觉应用自然和谐规律．     

中国蚱科昆虫分布格局的特有性简约性分析

我们用特有性简约性分析方法对中国蚱科昆虫分布格局和各分布区之间的关系进行了探讨。根据蚱科昆虫的分布,构建特有性简约性分析所需的矩阵,以东北区作为外群,用最大简约法通过穷尽式搜索得到分布区分支图。分布区分支图上8大生物地理分布区可分成4个聚类群：第一个聚类群是东北区;第二个聚类群是蒙新区;华中区、华东区及华北区组成第三个聚类群;华南区、西南区及青藏区则组成第四个聚类群。分布区分支图表明东北区与蒙新区比其他生物地理分布区形成要早,其原因我们推测可能与更新世的冰川活动有关。总体上来说,中国蚱科昆虫生物多样性南部比北部丰富,我们认为可从两方面来解释,一是更新世森林避难所的形成,二是生态环境的恶化。     

一个新的分支系统分析方法，中值淘汰法

本文评述了分支系统分析中最简原理或简约性在系统发育推论中的应用和存在的问题。在系统发育推论中使用简约性存在的主要问题在于,既无法获得最简约的系统树也不一定得到一个单一的解决办法。基于此,本文作者接受了Hennig用衍生性状来判断生物之间相似性的同时,用近代大多数生物系统学家接受的进化论各项原理代替Popper的简约性原理,以寻求单一的解决办法和获得确定性的结果为目标,提出了一个新的分支系统分析方法——中值淘汰法,用以研究系统发育。这个方法除了使用衍生性状来判断生物类群之间的亲缘关系外,还强调包括原始的也包括衍生性状在内的性状镶嵌组合在决定分支和辨别分类群过程中的作用。     

圆偏振光对二维旋转化学波的诱发性和选择性

本文用分支理论分析了在临界点附近圆偏振光对二维旋转化学波的诱发性和选择性,并讨论了可能具有的生物学意义。     

蜡梅科植物的分支分析

蜡梅科是一个仅有４属,１０种的小科,将蜡梅科的生物信息数字化,利用徐克学的和谐性分析程序,剔除了不合理的性状安排,判别关系含糊的性状极性,利用最大同步法,最小平行演化法及最大离散量分支分类法,对由性状再分析后获得的数值矩阵进行运算,推导分支图,明确各属之间的发生、发展和演化的关系。结果表明：椅子树亚科（Ｉｄｉｏｓｐｅｒｍｏｉｄｅａｅ）的椅子树属（Ｉｄｉｏｓｐｅｒｍｕｍ Ｂｌａｋｅ）在整个蜡梅科（Ｃ     

Chmostat系统中Hopf分支的存在性

应用Hopf分支理论研究了具有比例确定增长率的Chmostat系统存在Hopf分支的条件,同时得到周期解的存在性及稳定性的结果.     

让学生在愉快和谐的氛围中主动发展：黑龙江省中学生物和谐教学实验简介

起源于山东省的“和谐教改实验”是我国教改实验园中的一朵奇葩。几年来,黑龙江省生物教研室在对和谐教学法进行引进、改造、融合和创新的过程中,已经逐渐形成了具有生物学科特点的、体现素质教育宗旨的生物课堂教学改革模式,现已在部分实验地区和实验学校,初步取得较好的教学效果。１　“和谐教学”的课堂教学模式和谐教学是指在教学活动中,力求使教学过程诸要素之间以及教学过程与教学环节之间始终处于一种协调、平衡的状态,从而提高教学质量,减轻学生负担,使学生全面发展。和谐教学的课堂教学程序分为３个阶段８个环节。１．１　…     

在住院处深入开展以人为本与和谐共存服务理念的探讨

目的：为构建和谐的医患关系,为病人提供优质服务,结合住院处的实际情况,探讨在医院住院处深入开展以人为本与和谐共存服务理念的重要性和必要性。方法：详细介绍以人为本与和谐共存服务理念,简要概括医院住院处的工作职责及其在医院系统中的作用和地位,将以人为本与和谐共存服务理念与医院住院处的职责相结合,探讨该理念在提升住院处的工作职能、促进与患者的沟通交流、提升医院信誉、维护医院形象中的作用。结果：以人为本与和谐共存服务理念在指导住院处各项工作中确实有一定的引导作用。结论：将以人为本与和谐共存服务理念在提升住院处的工作职能相结合,可以很好地促进医务人员与患者的沟通交流,提升医院信誉,提高医院竞争力。     

金缕梅类科的系统发育分析

本文运用分支分类的方法对金缕梅类进行了系统发育的分析。金缕梅类作为单元发生群包括下 列19科：昆栏树科、水青树科、连香树科、领春木科、杜仲科、金缕梅科、悬铃木科、交让木科、假槲树科、双颊果科、折扇叶科、黄杨科、西蒙得木科、木麻黄科、山毛榉科、桦木科、杨梅科、马尾树科和胡桃科。木兰科在分析中被选择作为外群类。在对大量性状进行评估之后,选择了32对性状作为建立数据矩阵的基本资料。性状极化主要以外类群比较、化石证据和通行的形态演化规律为依据。首次引入了不合谐数的概念来检测性状极化结果的正确程度,并对少数不合谐数较大的性状的极性进行了调整。采用最大同步法、最小平行进化法和综合分析法进行运算,按照最简约的原则,选出演化长度最短的谱系分支图,作为本文讨论的基础,并在此基础上,探讨了金缕梅类科的系统关系。     

Inferring and testing hypotheses of cladistic character dependence by using character compatibility

The notion that two characters evolve independently is of interest for two reasons. First, theories of biological integration often predict that change in one character requires complementary change in another. Second, character independence is a basic assumption of most phylogenetic inference methods, and dependent characters might confound attempts at phylogenetic inference. Previously proposed tests of correlated character evolution require a model phylogeny and therefore assume that nonphylogenetic correlation has a negligible effect on initial tree construction. This paper develops "tree-free" methods for testing the independence of cladistic characters. These methods can test the character independence model as a hypothesis before phylogeny reconstruction, or can be used simply to test for correlated evolution. We first develop an approach for visualizing suites of correlated characters by using character compatibility. Two characters are compatible if they can be used to construct a tree without homoplasy. The approach is based on the examination of mutual compatibilities between characters. The number of times two characters i and j share compatibility with a third character is calculated, and a pairwise shared compatibility matrix is constructed. From this matrix, an association matrix analogous to a dissimilarity matrix is derived. Eigenvector analyses of this association matrix reveal suites of characters with similar compatibility patterns. A priori character subsets can be tested for significant correlation on these axes. Monte Carlo tests are performed to determine the expected distribution of mutual compatibilities, given various criteria from the original data set. These simulated distributions are then used to test whether the observed amounts of nonphylogenetic correlation in character suites can be attributed to chance alone. We have applied these methods to published morphological data for caecilian amphibians. The analyses corroborate instances of dependent evolution hypothesized by previous workers and also identify novel partitions. Phylogenetic analysis is performed after reducing correlated suites to single characters. The resulting cladogram has greater topological resolution and implies appreciably less change among the remaining characters than does a tree derived from the raw data matrix.     

When molecules and morphology clash: reconciling conflicting phylogenies of the Metazoa by considering secondary character loss

Molecular and morphological data sets have yielded conflicting phylogenies for the Metazoa. So far, no general explanation for the existence of this conflict has been suggested. However, I believe that a neglected aspect of metazoan cladistics has introduced a systematic and substantial bias into morphological phylogenetic analyses. Most characters used for metazoan cladistics are coded as binary absence/presence characters. For most of these characters, the absence states are assumed to be uninformative default plesiomorphies, if they are defined at all. This character coding strategy could seriously underestimate the number of informative apomorphic absences or secondary character losses. Because nodes in morphological metazoan phylogenies are typically supported by relatively small numbers of characters each with a potentially strong impact on tree topology, failure to distinguish between primary absence and secondary loss of characters before a cladistic analysis may mislead morphological cladistics. This may falsely suggest conflict with molecular phylogenies, which are not sensitive to this bias. To test the existence of this bias, I compare the phylogenetic placement of a variety of metazoan taxa in molecular and morphological trees. In all instances investigated here, phylogenetic conflict can be resolved by allowing for secondary loss of morphological characters, which were assumed to be primitively absent in cladistic analyses. These findings suggest that we should be cautious in interpreting the results of morphological metazoan cladistic analyses and additionally illustrate the value of a more functional approach to comparative morphology in certain circumstances.     

Relations phylogénétiques chez les marchantiales (Hepaticae). Incongruence apparente entre données morphologiques et moléculaires

A cladistic analysis of the order Marchantiales based on morphological characters (43 characters) did not agree with the classification in current use. Molecular sequences of nuclear-encoded 26S rRNA genes of seven species of the order and two out-groups (1254–1299 bp) were analysed to solve this contradiction. Results between morphologial and sequence data are conflicting. The combination of the two data sets shows that a weighting of the morphological data corresponding to equal contributions of the two sets resolves contradiction. We demonstrate that the structure of two data sets can be compatible even if the resultant trees are incongruent. Addition of a few compatible data (for instance, via character weighting) can result in congruent trees. The taxonomic incongruence we observed could illustrate a case of too limited molecular sampling.     

The scientific status of metazoan cladistics: why current research practice must change

Jenner, R. A. (2004). The scientific status of metazoan cladistics: why current research practice must change. —Zoologica Scripta, 33, 293–310. Metazoan phylogenetics is bustling with activity. The use of comprehensive morphological data sets in recent phylogenetic analyses of the Metazoa indicates that morphological evidence continues to play a key role in the reconstruction of metazoan deep history. In this paper I review the scientific status of morphological metazoan cladistics from the perspective of cladistic research cycles. Each research cycle consists of three main steps: (1) the compilation of a data matrix (2) the simultaneous evaluation of all possible cladograms in a character congruence test, and (3) the assessment of the relationship between evidence and hypothesis after finding the optimal tree. I identify a striking discrepancy between the sophistication of the analysis of given data sets (Step 2), and their compilation and the interpretation of the results (Steps 1 and 3). The latter two steps deserve far greater attention than is current practice. Uncritical and nonexplicit character selection, character coding, and character scoring seriously compromise Step 1. Careful comparative morphological study prior to data matrix construction is necessary to remedy this problem in future cladistic analyses. Step 2 is the locus of most recent advances in metazoan cladistics through the increasing availability of computing power, and the development of increasingly efficient phylogenetic software that allows analysis of large data sets. Failure to identify problems and errors generated in Step 1 of the research cycle is testament to the general failure of Step 3. Consequently, recent progress in metazoan cladistics is primarily analytical, while the only empirical anchor of the discipline receives surprisingly little attention. Not surprisingly, the first generation of modern metazoan phylogeneticists used computers principally as a relatively quick and easy means to generate abundant phylogenies from morphological data. The next phase should build on this foundation by critically testing these alternative hypotheses by a thorough qualitative reassessment and elaboration of morphological data matrices, and a more critical approach to data selection. A rigorous research program for metazoan cladistics can only be established when the cladistic research cycle is properly completed, and when subsequent research cycles are effectively linked to previous efforts.     

Incongruence between cladistic and taxonomic systems

Cladistic and taxonomic treatments of the same plant group usually exhibit a mixture of congruences and incongruences. The question arises in the case of the incongruences as to which version is right and which is wrong. Many cladists believe that cladistics is a superior approach and gives the best results. There are several conceptual and methodological differences between cladistics and taxonomy that cause incongruence. One important conceptual difference is the use of different criteria for grouping: order of branching vs. similarity and difference (clades vs. taxa). Another is the policy regarding paraphyletic groups: to ban them in cladistics but ignore the ban in taxonomy. These two differences automatically lead to some incongruences. One approach is not right and the other wrong; each is operating by its own standards. However, when cladists apply the paraphyly rule to a taxonomic system and conclude that it needs revision to eliminate paraphyly, as cladists often do, they are judging the taxonomic system by a wrong standard. Several differences between the two schools in the use and handling of characters can also cause incongruence. First consider phenetic characters. Taxonomy uses a very wide range of these, whereas phenetic cladistics sets restrictions on the selection of characters, which deprive it of potentially useful evidence. Taxonomic systems generally rest on a broader empirical foundation than phenetic cladistic systems. Next, consider molecular cladistics, which is the leader in the use of DNA evidence. Two sources of incongruence between molecular cladistics and taxonomic systems can come into play here. First, the molecular evidence used in cladistics comes mainly from cytoplasmic organelles, whereas taxonomic systems are based on characters that are determined mainly by the chromosomal genome. More generally, the database in a molecular cladogram is, in itself, too narrow to serve as a foundation for an organismic classification. In cases of incongruence, the molecular evidence can be a reliable indicator of taxonomic relationships sometimes, misleading other times, and may afford no clear basis for a systematic decision. In this situation, it is helpful, indeed necessary, to integrate the molecular evidence with the phenetic evidence and bring more characters to bear on the question.     

Compatibility analysis and its applications

A two-state character is defined as uniquely derived if it has only evolved once in the history of a group, without subsequent reversal. Two independent characters cannot both be uniquely derived if all four possible combinations (or all three excluding that of the two ancestral forms) occur.
A number of ways of choosing compatible sets of uniquely derived characters are discussed and used to derive possible unrooted and rooted trees. Results of these are related to those chosen on parsimony criteria, using data for orthopteroid groups, and the assumptions of both methods are compared. Application of compatibility analysis to the moth genera Teldenia and Argodrepana is also discussed. Compatibility and parsimony methods are complementary rather than exclusive of each other.     

Cladistic analysis of molecular and morphological data

Considerable progress has been made recently in phylogenetic reconstruction in a number of groups of organisms. This progress coincides with two major advances in systematics: new sources have been found for potentially informative characters (i. e., molecular data) and (more importantly) new approaches have been developed for extracting historical information from old or new characters (i. e., Hennigian phylogenetic systematics or cladistics). The basic assumptions of cladistics (the existence and splitting of lineages marked by discrete, heritable, and independent characters, transformation of which occurs at a rate slower than divergence of lineages) are discussed and defended. Molecular characters are potentially greater in quantity than (and usually independent of) more traditional morphological characters, yet their great simplicity (i. e., fewer potential character states; problems with determining homology), and difficulty of sufficient sampling (particularly from fossils) can lead to special difficulties. Expectations of the phylogenetic behavior of different types of data are investigated from a theoretical standpoint, based primarily on variation in the central parameter λ (branch length in terms of expected number of character changes per segment of a tree), which also leads to possibilities for character and character state weighting. Also considered are prospects for representing diverse yet clearly monophyletic clades in larger-scale cladistic analyses, e. g., the exemplar method vs. “compartmentalization” (a new approach involving substituting an inferred “archetype” for a large clade accepted as monophyletic based on previous analyses). It is concluded that parsimony is to be preferred for synthetic, “total evidence” analyses because it appears to be a robust method, is applicable to all types of data, and has an explicit and interpretable evolutionary basis. © 1994 Wiley-Liss, Inc.     

An Algorithm for Cladistics—Method of Minimal Parallel Evolution

The paper presented here is Concerned with the numerical cladisties. In consideration of the fact that the parallel evolution has close relation to the length of evolution graph, a new method of reconstructing evolutionary tree has been developed for the application and practice of cladistics. The procedure of the algorithm of the new method presented in Table I is similar to the method described in paper "An algorithm for cladistics method of maximal same step length". An essential step of the algorithm is how to decide the coefficient between two cladistic units (CTUs). A coefficient called parallel evolutionary coefficient between CTUp and CTUq is defined as follows: where the j is code of CTU and the i is code of character; E(p, q, i, j) is a function given by following expression: min (X_ij, Xpj)+(X_ij, Xqj)-2min(Xpj, Xqj) as Xij>min (Xpj, Xqj) E(p,q, i,j ) = 0 otherwise. where the X_ij is the ith row (CTU) jth colunm (Character) element of the data matrix. Because the method of minimal parallel evolution is closely related to the length of evolutionary graph, it is superior to the method of maximal same step length. A simple datum as an example for comparison shows that the method of minimal parallel evolution can arrive at a better result. But in some cases, we may combine one method with another and thus the coefficient should take following form: S(S_ij)=M·S (C) _ij-N·S(P) _ij in which S (C) _ij and S (P) _ij are the same step coefficients and the parallel evolution coefficient respectively, and the M and N are positive integers as a weightnumber being given in advance.     

Methods of systematic analysis: the relative superiority of phylogenetic systematics

The superiority of cladistic methods to both synthetic and phenetic methods is briefly advanced and reviewed. Cladistics creates testable hypotheses of phylogeny that also give a highly informative summary of available data. Thus it best fits the criteria for a method for determining the general reference classification in biology. For protistologists in particular, cladistics is especially useful. Inundated by an abundance of ultrastructural, biochemical, and cell biological information, protistologists could be greatly helped by the informative way in which cladistics orders and summarizes the data. In addition to classifying protist taxa, hypotheses about the evolution of cell organelles and cellular could be scientifically formulated and tested by cladistics . Because cladistic classifications best summarize the data, they would also be best for making predictions about taxa and characters. They would, for the same reason, be the most stable. Widespread adoption of cladistic methods would serve to stabilize the now fluid state of protist taxonomy. It is for all of these reasons that such methods best suit the needs of the evolutionary protistologist .     

Methods of systematic analysis: The relative superiority of phylogenetic systematics

The superiority of cladistic methods to both synthetic and phenetic methods is briefly advanced and reviewed. Cladistics creates testable hypotheses of phylogeny that also give a highly informative summary of available data. Thus it best fits the criteria for a method for determining the general reference classification in biology.For protistologists in particular, cladistics is especially useful. Inundated by an abundance of ultrastructural, biochemical, and cell biological information, protistologists could be greatly helped by the informative way in which cladistics orders and summarizes the data. In addition to classifying protist taxa, hypotheses about the evolution of cell organelles and cellular could be scientifically formulated and tested by cladistics. Because cladistic classifications best summarize the data, they would also be best for making predictions about taxa and characters. They would, for the same reason, be the most stable. Widespread adoption of cladistic methods would serve to stabilize the now fluid state of protist taxonomy. It is for all of these reasons that such methods best suit the needs of the evolutionary protistologist.