THE ORIGIN OF MORPHOLOGICAL CHARACTERS AND THE BIOLOGICAL BASIS OF HOMOLOGY

A homolog is a part of the phenotype that is homologous to equivalent parts in other species. A biological homology concept is expected to explain three properties of homologs: 1) the conservation of those features that are used to define a homolog, 2) the individualization of the homolog with regard to the rest of the body, and 3) the uniqueness of homologs, i.e., their specificity for monophyletic groups. The main obstacle to describing a mechanistic basis for homology is the variability of the developmental pathways of undoubtedly homologous characters. However, not all aspects of the developmental pathway are of equal importance. The only organizational features of the developmental system that matter are those that have been historically acquired and cause developmental constraints on the further evolutionary modification of the characters. Two main factors contribute to historically acquired developmental constraints: generative rules of pattern formation and ontogenetic networks. In particular, hierarchical and cyclical inductive networks have the required properties to explain homology. How common such networks are is an open empirical question. The development and variation of pectoral fin hooks in blenniid fishes is presented as a model for the study of a simple ontogenetic network.     

确认茶梨油茶的形态学和细胞核学证据

<正> 一、引言 山茶属Camellia L.的茶梨油茶C.octopetala Hu和博白大果油茶C.gigantocarpa Hu 是胡先骕在1965年发表的新种,前者产浙江南部,后者产广西博白县,目前长江以南各省(区)均有引种。除种子油可食用,为我国南方的油用树种外,花大美丽,有作庭园观赏的价值。 1981年张宏达将这两种油茶都归并为红皮糙果茶C.crapnelliana Tutch.(糙果茶组Sect.Furfuracea Chang)的异名。但从形态上看,博白大果油茶和茶梨油茶不尽相同。     

REVISED CLASSIFICATION OF THE GENUS PACHYMENIA BASED ON MORPHOLOGICAL AND MOLECULAR CHARACTERS

Taxonomic discrimination in the genus Pachymenia (Rhodophyta) in New Zealand is based primarily on phenotypic characters of the thallus. The taxonomic problems raised by this classification method are due to highly variable thallus characters such as blade thickness, blade width, degree of thallus branching, and variation in anatomical characters. Delineation of species is further complicated by a lack of adequate knowledge about the responses of phenotype to environmental variation. There are currently three species recognized in this genus that are endemic to New Zealand: a prostrate species P. crassa , and two erect species, P. laciniata and P. lusoria. In this study, two approaches are used to investigate the current delineation of these species. Morphological and anatomical characters of field collected material and herbarium specimens from throughout the species' distributional ranges were quantified. Multivariate analyses were used to identify discrete phenotypic groups. Species relationships were further analyzed by quantifying the variation found within the internal transcribed spacer region (ITS) of the nuclear ribosomal DNA. The results obtained from both approaches will be discussed with regards to possible re-classification of species relationships within this genus. We suggest that the two erect species should be merged, and the currently recognized P. lusoria should be separated into at least two taxonomic groups.     

被子植物的起源-以喜花虻类化石为据

喜花昆虫在被子植物的起源和早期演化上起着决定性的作用。虻类化石中的许多类群都有访花习性,它们为研究被子植物的起源提供了独特材料。虽然最老的被子植物化石还没有发现,但是喜花虻类的爆发式出现,表示了被子植物出现的时间和地点。本文主要以欧亚大陆东部,特别是中国辽西的侏罗杨虻类化石为材料,在功能形态分析和与现代类群作对比的基础上,证证实了虻类是显花植物最原始的传粉类群之一。中国东北、哈萨克斯坦和西伯利来晚     

介形类系统分类与起源演化的形态、分子和化石证据

介形类(Ostracoda)因其丰富的化石记录和广布的海陆现生代表类群,而被认为是进化生物学中研究生物多样性产生机制和演变历程的颇具潜力的重要模式生物。介形类在甲壳亚门中的谱系发生位置、起源及其内部各类群间的系统关系还存在诸多争议。基于其体制构造的形态学特征,介形类被归入甲壳亚门下的颚足纲(Maxillopoda),但来自18S rDNA序列数据分析却显示Maxillopoda不是单系群。基于化石记录和壳体形态特征,高肌虫(Bradoriida)长期以来被认为是介形类的一个祖先类群,但保存有软躯体的早寒武世化石的研究表明,Bradoriida不是介形类甚至可能也不属于甲壳类。不同的研究者所强调的壳体和肢体形态特征各异,导致介形类最大的现生类群速足目(Podocopida)的四个超科之间的关系也存在诸多推测。壳体和肢体特征在系统演化意义上的不兼容,需要分子生物学等证据的介入。分子、形态和化石证据的积累及各种信息整合是系统演化研究的必然趋势。     

雀形目高级阶元分类与起源研究概况

对雀肜目鸟类高级阶元的分类和系统发育的研究进行了简要概述.经典分类与应用分子生物学方法建立的分类系统在高级阶元(总科)有较大差异,但科级的分类基本一致.在雀形目鸟类起源研究方面,古生物学研究结果认为其起源于劳亚古陆;而分子生物学的证据则认为其起源于冈瓦纳古陆.由于化石的证据与"分子钟"的推测年代相差较大,因此对雀形目鸟类的起源还存在争议,但是目前的研究更倾向于"冈瓦纳起源"假说.     

A NUMERICAL TAXONOMIC STUDY OF THE GENUS PLATANUS BASED ON MORPHOLOGICAL AND PHENOLIC CHARACTERS

Forty-two morphological and eighty chemical (phenolic) characters were employed on a numerical taxonomic study of the genus Platanus. Ten taxa were used for morphological study, and nine were available for chemical study. UPGA was employed for cluster analysis; correlation coefficients served as a measurement of the similarity between each OTU-pair. Comparison was made for phenograms and graph diagrams of nine taxa based on morphological characters with those based on chemical characters. It has been found that the two agree with each other in many respects. Correlation coefficient between similarity matrices based on morphological and chemical characters is 0.573. The result generally supports the belief that taxa closely related on morphological grounds are similar biochemically. A systematic consideration of the genus has been made, based on the information available.     

PHYLOGENY AND SYSTEMATICS OF THE GENUS MONOMORPHINA (EUGLENACEAE) BASED ON MORPHOLOGICAL AND MOLECULAR DATA1

Morphological studies of 16 strains belonging to the genus Monomorphina revealed a single, parietal, orbicular chloroplast in their cells. The chloroplast has a tendency to be perforated and disintegrates in aging populations and thus may appear to be many chloroplasts under the light microscope. A single chloroplast in the cells of Cryptoglena skujae is also parietally located and highly perforated. It never forms a globular and closed structure, but is open from the side of the furrow, resembling the letter C. We have verified the Monomorphina pyrum group (M. pyrum–like) on the basis of phylogenetic analysis of SSU rDNA and morphological data. The strain CCAC 0093 (misidentified as M. reeuwykiana) diverges first on the SSU rDNA phylogenetic tree. The rest of the M. pyrum–like strains form a tight cluster, subdivided into several smaller ones. Because morphological differences between the M. pyrum–like strains (including the strain CCAC 0093) do not conform to the tree topology, we suggest that they all (except the strain CCAC 0093) belong to M. pyrum. We designate a new species, M. pseudopyrum, for the strain CCAC 0093, solely on the basis of molecular characters. We also suggest that M. reeuwykiana and similar species should stay in Phacus and Lepocinclis unless detailed molecular and morphological studies show otherwise. Emended diagnoses of the genera Monomorphina and Cryptoglena and the species M. aenigmatica are also proposed, as well as the delimitation of an epitype for M. pyrum, the type species for the genus Monomorphina.     

A MORPHOLOGICAL CONSIDERATION OF THE RELATIONSHIPS OF PINNIPEDS TO OTHER CARNIVORANS BASED ON THE BONY TENTORIUM AND BONY FALX

The close relationships of pinnipeds to other carnivorans were studied based on morphological characteristics of the bony tentorium (BT) and bony falx (BF) of carnivorans. It appears to be an important characteristic of the Carnivora that the clear BT is present in almost all species including pinnipeds. The BF is present in all species of pinnipeds, and only in the genus Ursus among fissipeds observed.
The parietal bone of all otariids and odobenids observed shows an extremely characteristic form as compared with other carnivorans. The sagittal and squa-mous borders of the parietal bone of these groups are bridged by a thin bony plate which forms large portions of the BT and BF. In phocids, the aspects of the BT and BF vary among species, but are apparently distinct from those of otariids and odobenids.
The BT of carnivorans can be divided into four types which appear to be useful for classification of the Carnivora. On the basis of the BT and BF form, the Otariidae and Odobenidae appear to have a specific sister relationship to the Ursidae, while the Phocidae appears to have dose affinities to the Mustelidae. Morphological differences of the BT and BF among pinnipeds strongly support the diphyletic origin of pinnipeds.     

从核型看北美红杉的起源

本文分析了同源异源自然六倍体北美红杉的AA和B染色体组的组型,它们属Stebbins的“1A”和“1B”,经与杉科各属植物的核型比较后发现分别与相同类型的水杉和巨杉最为接近,因而认为水杉属和巨杉属的某个古代种可能是北美红杉的二个杂交亲本,水杉和巨杉则或许是它们的后裔或近缘。本研究支持Stebbins认为水杉属的某个古代种是红杉的一个祖先而水杉是它的直接后裔的假设,但与他认为另一个祖先已经灭绝并没有留下近缘的推测存在分歧。     

金丝猴分类及系统发育关系

本文对金丝猴的99项形态学特征的研究结果表明:川、滇、黔金丝猴应为三个独立的种;根据我国的地质变迁推测,川、滇金丝猴间分离最早,其次是川、黔金丝猴,最后是滇、黔金丝猴;由于特殊的生态环境,滇金丝猴是属中进化较完善者,而黔金丝猴是最原始者;至于分布在阿萨姆和上缅甸的金丝猴,如果存在,很可能是一个新种或属于滇金丝猴的一个新亚种。     

双滴虫与细胞核起源问题的探索──庆祝潘清华老师八十寿辰

分析了可能用作研究原始性细胞核的模型的涡鞭毛虫与双滴虫核,发现实际上只有后者是适用的。以蓝氏贾第虫（Ｇｉａｒｉｄｉａｌａｍｂｌｉａ）作为双滴虫类的代表,对其核作了多方面的考察,发现其核中确实还没有核仁;核被膜上有天然的缺口;但核内已经有了核骨架及５种组蛋白。比较的免疫印迹检查表明,在检查到的各种原生生物中,蓝氏贾第虫的着丝粒／动粒蛋白最接近于原细菌的相应蛋白。有人怀疑蓝氏贾第虫缺少线粒体及典型高尔基氏器等原始性特征实际上不过是由于过寄生生活所致。本文针对这种怀疑进行了多方面的分析。其实所有过自由生活的双滴虫类都没有线粒体及典型高尔基氏器,看来也全都没有核仁,核被膜全都有缺口。依据上述的发现,对真核细胞发生之初原始性细胞核的特性进行了推断,进而对细胞核的整个起源过程进行了分析：认为在真核细胞的原细菌祖先体内就已经有了核骨架;多个类核体的ＤＮＡ结合在其上而构成了核区。我们关于组蛋白的分子进化研究表明,核小体组蛋白的共同祖先在极早的时候就已经分化成了４种。因此可以相信,真核细胞的原细菌祖先很早就有了４种核小体组蛋白和核小体。本文着重分析了染色体的起源过程并进一步发展了过去已经提出的核被膜起源于原始性内质网的学说（     

植物生理生态学的学科起源与发展史

探讨了植物生理生态学的起源及其发展问题。植物生理生态学是植物生态学的一个分支,它主要是用生理的观点和方法来分析生态学现象。从现有的资料看,该门学科的创始人当为德国学者辛泊尔(A. F. W. Schimper);但近代最早建议将植物生理生态学作为独立的学科的为比林斯(W. D. Billings);拉夏埃尔(W. Larcher)为该门学科在国际上的传播起到了非常重要的作用。在中国,近代植物生理生态学的发展应归功于李继侗先生;然而,李博先生对拉夏埃尔《植物生理生态学》的翻译出版促进了该门学科在中国的传播。植物生理生态学目前在国内外发展十分迅速,由于它能够对一些生态学现象以及资源的可持续利用给以机理上的解释,因此越来越受到研究者的重视。     

PHYLOGENETIC RELATIONSHIP OF COLEOCHAETE AND CHAETO-SPHAERIDIUM (COLEOCHAETALES) BASED ON THE CHLOROPLAST GENES RBCL AND ATPB

The freshwater green alga Coleochaete Breb. (Coleochaetaceae; Coleochaetales) is a key streptophyte genus and is important to the understanding of the evolutionary origin of embryophytes (land plants). To date only a few species have been available from public culture collections. To facilitate research on this genus we have isolated 17 previously uncultured species of Coloechaete from material collected in the United States, Puerto Rico, and the Dominican Republic. Sequences for the genes rbcL and atp B were determined for these new isolates of Coleochaete (and for existing cultures) and combined with sequences from representative other streptophytes. Phylogenetic analyses indicate that Coleochaete , along with Chaetosphaeridium and Chara , are closely related to embryophytes and constitute a 'higher streptophyte' clade. At least four well-supported lineages exist within Coleochaete. Characteristic growth forms have been identified for these four lineages, with important characters including aspects of thallus establishment, thallus habit, zygote development and hair sheath position. These data provide an improved understanding of species diversity and character evolution in the genus Coleochaete , and facilitate examination of hypotheses concerning character evolution in the streptophytes.     

对枝蜈蚣藻的修订研究——基于形态特征和基因序列分析

通过形态观察结合rbcL和COⅠ基因序列分析的方法, 对采自广东省汕头市、浙江省温州市和辽宁省大连市的对枝蜈蚣藻Grateloupia didymecladia Li et Ding的11个标本进行了重新鉴定。结果表明: (1)藻体单生或丛生, 红褐色或深红色, 质地黏滑、肉质、衰老时软骨质, 成熟藻体直立, 高15—50 cm, 主枝明显, 扁平, 宽3—15 mm, 厚约1 mm, 末端渐尖, 1—3回羽状分枝。小枝对生或互生, 生长在主枝上或主枝边缘, 基部缢缩, 长短不一, 最长可达15 cm; 配子体为雌雄异体, 果胞枝生殖枝丛和辅助细胞生殖枝丛均为Grateloupia型, 果胞枝生殖枝丛主枝由5个细胞组成, 辅助细胞生殖枝丛主枝由4个细胞组成(5cpb-4auxb型); 四分孢子囊由四分孢子体的内皮层细胞产生, 呈十字形分裂。以上特征均与亚栉状蜈蚣藻G. subpectinata Holmes一致。(2)基于rbcL基因序列构建的系统树显示, 11个样本之间无碱基差异, 形成独立的进化支, 与产于韩国和日本的亚栉状蜈蚣藻G. subpectinata Holmes碱基差异分别为1 bp (0.08%)和2 bp (0.17%), 属于种内差异; 基于COⅠ基因序列构建的系统树显示, 11个样本之间无碱基差异, 形成独立的进化支, 与韩国产的亚栉状蜈蚣藻碱基差异为1 bp (0.18%), 属于种内差异。根据形态、结构及基因序列分析, 确定对枝蜈蚣藻与亚栉状蜈蚣藻为同一种, 根据优先法则, 将对枝蜈蚣藻G. didymecladia Li et Ding作为亚栉状蜈蚣藻G. subpectinata Holmes的同物异名。亚栉状蜈蚣藻为中国新记录种。