Intraspecific Variation in Developmental Characters: The Origin of Evolutionary Novelties

Evolutionary developmental biology is inevitably a comparativesubject. However, the taxonomic level at which comparisons canbe made varies widely, and this greatly affects the kind ofinformation that can be gained from the comparison. Broadlyspeaking, high-level comparisons (e.g., between phyla) are moreinformative about phylogenetic pattern and homology, while low-levelcomparisons (e.g., between congeneric species) are more informativeabout evolutionary mechanisms, including speciation. However,so far evolutionary developmental biology has had a relativelyminor input into the traditional territory of population genetics,namely comparisons within species—both within and betweengeographic populations. Yet this area is crucial, as all evolutionarynovelties ultimately arise from intraspecific variation. Here,I address this issue, focusing on the question of how earlyin development novelties arise. To shed light on this question,I discuss two examples of developmental polymorphism withinspecies involving two of the main body axes: anteroposteriorsegmentation in centipedes and left–right asymmetry (chirality)in gastropods.     

Do Organisms Exist?

What is the status of organisms in modern evolutionary biology?I argue that this is a question which centers on the questionof reduction, and towards a complete answer, I pursue issuesthrough three different senses of the term: ontological, methodological,and epistemological. The first sense refers to the ultimatestatus of the entities of the organic world, and in this senseI argue that organisms have no special status. The second senserefers to the question of organization, and I argue that inthe light of modern evolutionary biology organisms do have adistinctive "design-like" organization. The third sense refersto the relationship between theories, in particular to whetherthe theories of the biological sciences can be shown to be logicalconsequences of the theories of the physical sciences. I arguethat such reduction may be possible in principle but difficultin practice. However, from the perspective of the working scientist,this hardly matters. In conclusion, I argue that in some respectsorganisms are not distinctive and in other respects they are.Certainly biologists need not worry for the autonomy of theirsubject.     

优雅蝈螽与暗褐蝈螽精子束的显微观察

本文应用微分干涉相衬法对优雅蝈螽Ｇampsocleis gratiosa Brunner von Wattenwyl和暗褐蝈螽G. sedakovii （Fischer von Waldheim） 雄性精巢管基部、输精管、贮精囊和精包,及雌性受精囊中精子束的形态变化进行了观察,对探讨螽斯近缘种的生殖隔离机制和生殖生物学具有重要意义.结果表明：这两种蝈螽的精子束通过精包转移到雌性受精囊后,精子束的形态发生了显著变化.精巢管基部的精子为游离的单个精子;输精管、贮精囊和精包中精子成束排列形成较分散的精子束,精子束头部包裹有粘液帽;雌性受精囊中的精子束的精子呈羽状排列,精子的头部汇集在中央轴上.两种蝈螽精子束形态差异不显著.     

How Effectively Does a Clinostat Mimic the Ultrastructural Effects of Microgravity on Plant Cells?

Columella cells of seedlings of Zea mays L. cv. Bear Hybridgrown in the microgravity of orbital flight allocate significantlylarger relative-volumes to hyaloplasm and lipid bodies, andsignificantly smaller relative-volumes to dictyosomes, plastids,and starch than do columella cells of seedlings grown at I g.The ultrastructure of columella cells of seedlings grown atI g and on a rotating clinostat is not significantly different.However, the ultrastructure of cells exposed to these treatmentsdiffers significantly from that of seedlings grown in microgravity.These results indicate that the actions of a rotating clinostatdo not mimic the ultrastructural effects of microgravity incolumella cells of Z. mays. Zea mays L., gravity, microgravity, ultrastructure, clinostat, space shuttle, space biology     

Genomics of Basal metazoans

An in-depth understanding of the biology of animals will requirethe generation of genomics resources from organisms from allphyla in the metazoan phylogenetic tree. Such resources willideally include complete genome sequences and comprehensiveEST (expressed sequence tag) datasets for each species of interest.Of particular interest in this regard are animals in the earlydiverging non-bilaterian phyla Porifera, Placozoa, Cnidaria,and Ctenophora. Publications describing the results from theuse of genomics approaches in these phyla have only recentlybegun to appear (Kortschak et al., 2003; Yang et al., 2003;Steele et al., 2004). Issues to be considered here include choosingthe basal metazoan species to examine with genomics approaches,the relative advantages and disadvantages of genome sequencingversus EST projects, and the resources and infrastructure requiredto carry out such projects successfully.     

线性和指数回归方法对土壤呼吸CO2扩散速率估算的影响

 理论上,土壤呼吸通量的量值可以通过观测土壤呼吸CO₂扩散速率(əc/ət)计算得到。但是为获得əc/ət,通常须允许土壤呼吸箱内CO₂浓度升高,因此,如何估算外界大气CO₂浓度条件下的əc/ət是土壤呼吸观测技术的关键,关系到观测结果的准确性。通常əc/ət的估算会受土壤表层大气CO₂扩散梯度(即土壤呼吸箱内CO₂扩散梯度和大气CO₂浓度昼夜变化)的影响。目前,线性回归方法是土壤呼吸观测中估算əc/ət的基本方法。然而,常用的线性回 归方法会低估əc/ət,而指数回归方法则可以准确地估算əc/ət。夜间əc/ət的变化与大气CO₂ 浓度之间存在非常明显的负相关关系。夜间土壤表层大气CO₂扩散梯度的减小导致线性回归方法明显低估əc/ət。əc/ət的昼夜变化过程存在明显的非对称性现象,而指数回归方法可以更好地描述əc/ət昼夜变化的非对称性响应。     

Kingdom animalia: The zoological malaise from a microbial perspective

Pain and cognitive dissonance abounds amongst biologists: theplant-animal, botany-zoology wound has nearly healed and thenew gash—revealed by department and budget reorganizations—is"molecular" vs. "organismic" biology. Here I contend that resolutionof these tensions within zoology requires that an autopoietic-gaianview replace a mechanical-neodarwinian perspective; in the interestof brevity and since many points have been discussed elsewhere,rather than develop detailed arguments I must make staccatostatements and refer to a burgeoning literature. The first centralconcept is that animals, all organisms developing from blastularembryos, evolved from single protist cells that were unableto reproduce their undulipodia. The second points to the usefulnessof recognizing the analogy between cyclically established symbiosesand meiotic sexuality     

两种麦蚜取食诱导小麦抗性品种后对后来取食蚜生物学特性的影响

刺吸式昆虫在刺吸作物韧皮部取食后会影响作物的正常生长发育,随着作物抗性及昆虫种类的不同,作物反过来也会对昆虫造成或正或反的影响,然而一种刺吸式昆虫取食后对后来者有什么样的影响目前尚不确定。本研究通过严谨的实验方法,即选定3个不同国家的小麦抗性品种98-10-30、Amigo和Batis,在所有条件严格统一的人工智能控制温室内,通过各处理在同一植株上先后不同的接蚜方式,分别测定了麦二叉蚜Schizaphis graminum (Rondani)和麦长管蚜Sitobion avenae Fab.在前期被蚜虫危害的抗虫品种98-10-30、Amigo和Batis上的发育历期、体重差及相对日均体重增长率(mean relative growth rate MRGR)等生物学参数。结果表明：品种不同,蚜虫在不同处理条件下取食作物时受到的影响也不同,即在品种98-10-30上,通过与前期不接虫的对照及前期接不同麦蚜的相关处理比较,麦长管蚜对后期取食的麦二叉蚜(MRGR=0.0974±0.0071)具有抑制作用,而麦二叉蚜对后期取食的麦长管蚜(MRGR=0.1614±0.0048)却有促进作用;在品种Amigo上,前期麦蚜的危害对麦长管蚜的取食具有促进作用,而在品种Batis上前期危害对麦二叉蚜的取食具有促进作用。同时明确了3个品种对两种蚜虫的抗性状况,即在前期无蚜虫危害时,品种98-10-30和Batis对两种麦蚜的抗性相当;在前期有麦蚜危害时,品种98-10-30对麦二叉蚜的抗性较好,而品种Batis对麦长管蚜的抗性较好;品种Amigo无论在任何处理下均对麦二叉蚜的抗性较好。     

Developmental Data and Phylogenetic Systematics: Evolution of the Vertebrate Limb

Among the primary contributions of phylogenetic systematicsto the synthesis of developmental biology and evolution arephylogenetic hypotheses. Phylogenetic hypotheses are criticalin interpreting the patterns of evolution of developmental genesand processes, as are morphological data. Using a robust phylogeny,the evolutionary history of individual morphological or developmentalfeatures can be traced and ancestral conditions inferred. Multiplecharacters (e.g., morphological and developmental) can be mappedtogether on the phylogeny, and patterns of character associationcan be quantified and tested for correlation. Using the vertebrate forelimb as an example, I show that bymapping accurate morphological data (homologous skeletal elementsof the vertebrate forelimb) onto a phylogeny, an alternativeinterpretation of Hox gene expression emerges. Teleost fishesand tetrapods may share no homologous skeletal elements in theirforelimbs, and thus similarities and differences in Hox patternsduring limb development must be reinterpreted. Specifically,the presence of the phase III Hox pattern in tetrapods may notbe correlated with digits but rather may simply be the normalexpression pattern of a metapterygium in fishes. This exampleillustrates the rigorous hypotheses that can be developed usingmorphological data and phylogenetic methods. "Creating a general reference system and investigating the relationsthat extend from it to all other possible and necessary systemsin biology is the task of systematics." (Hennig, 1966, p.7)     

Molecular Ecology of Teleost Fish Hemoglobins Strategies for Adapting to Changing Environments

Animals live in environments where physical chemical and biologicalparameters are continually changing. If homeostasis is to bemaintained animals must adapt. The respiratory complex (and specifically hemoglobins) is perhapsthe best system to use to study adaptation to environmentalstress because it exists at the organism environment interface.Fish are particularly useful in such studies since they responddirectly to such variables as temperature oxygen pH and salinity. Maintenance of respiratory homeostasis is achieved by a hostof molecular cellular and physiological mechanisms. The linkagebetween these molecular interactions the animals and the physicochemicalenvironment. I have termed Molecular Ecology. In the followingpaper I will consider some of these relationships.     

Pollination Biology of Piperaceae Species in Southeastern Brazil

Phenology, floral biology and breeding system are describedfor 14 Piperaceae species at two sites covered by semi-deciduousforest in southeastern Brazil. Flowering occurred continuouslythroughout the year, with a peak during the windy months. Allspecies had minute odorous and nectarless flowers visited byinsects; five of them showed a substantial degree of self-compatibility,and one was andromonoecious. Seven species were wind pollinated,and three were exclusively pollinated by insects. Flower visitorswere mainly hoverflies and bees. Copyright 2000 Annals of BotanyCompany Piper spp., Ottonia spp., Pothomorphe umbellata, pepper family, phenology, floral biology, breeding system, ambophily, semi-deciduous forest     

Pollination Ecology ofChloranthus serratus(Thunb.) Roem. et Schult. andCh. fortunei(A. Gray) Solms-Laub. (Chloranthaceae)

Flowering and pollination biology ofChloranthus serratusandChloranthusfortuneiwere studied. Flowering took place from early Marchto mid–April inCh. fortunei, and from April to September,the whole growth period, inCh. serratus.The flowering periodof an inflorescence ofCh. serratusaveraged about 8 d and anthesisof a single flower was 5–6 d. Flowers are slightly protogynous.The flower emitted fragrance when the androecium became white.Both species are entomophilous with thrips as exclusive pollinators.Under natural conditions, fruit set occurs mainly as a resultof cross-pollination, but self-pollination and agamospermy mayoccur in some cases. In flowers ofCh. fortuneiandCh. serratus,theincurved androecium, the carpel and the spike axis form a nearlyclosed chamber that contains the anthers and stigma. The developmentof a floral-axial chamber may be an important step towards amore economical and effective pollination system. Floral morphology,pollination biology and fossil evidence suggest that the mainevolutionary trend in the genusChloranthusis towards developmentof ‘closed’ flowers. The fidelity of the relationshipbetweenChloranthusand thrips is regarded as a specialized featureof pollination biology and this relationship may have originatedearly in the evolutionary lineage.Copyright 1999 Annals of BotanyCompany Chloranthaceae,Chloranthus, Thysanoptera,flowering, floral-axial chamber, pollination, evolution trends.     

不同地理种群银杏大蚕蛾COI基因序列变异与遗传分化

银杏大蚕蛾Caligula japonica是亚洲东部的特有种, 既是一种重要的林业害虫, 也是一种珍贵的野生蚕类资源。为了揭示银杏大蚕蛾地理种群间的内在联系, 测定了我国分布的12个地理种群的线粒体细胞色素氧化酶C亚基I（COI）基因部分序列（GenBank登录号: FJ358506-FJ358517）, 对地理种群间的序列变异和遗传分化进行了分析。结果表明: 银杏大蚕蛾地理种群间的COI序列同源性高达99%~100%, 显示出比较小的遗传差异。序列对准后从供试COI序列中仅鉴定出9个变异位点和6个单元型, 其中3种是共享单元型。系统发育分析结果表明种群间已经按地理位置形成了一定的地理格局, AMOVA分析显示北方组和南方组之间已经具有明显的遗传分化（FST=0.478, P<0.001）。综合分析, 我们认为北方组和南方组之间的遗传分化可能与差异巨大的生态条件有关。研究结果为银杏大蚕蛾的种群遗传学和生态学研究提供了一个基本的分子生物学线索。     

Parallel time courses of electrochromic shifts of carotenoids and cytochrome f photooxidation in intact Bryopsis chloroplasts

Light-induced absorbance changes at 560 nm, and electrochromicshifts in absorption of carotenoids responding to membrane potentialacross the thylakoid membrane, were studied, comparing themwith the kinetics of cytochrome f photooxidation, in the dark-adaptedintact chloroplasts of the green alga Bryopis maxima. The 560nm changes showed transient variations, characterized by a sharpinitial peak followed by a second, lower peak, within a fewseconds of illumination. The time course of the 560 nm changesis parallel to that of light-induced transient changes of cytochromef. Inhibitors and redox substances which selectively influenceddifferent transient phases of the cytochrome f induction alsospecifically affected corresponding transient phases of the560 nm changes. These results indicate that the two inductionphenomena are closely related to each other and that the inductionof the 560 nm change is due to light-dependent changes in electrontransfer on the reducing side of photosystem I. A possible mechanismfor the electric field formation by electron transfer associatedwith photosystem I will be discussed. (Received May 9, 1977; )     

Terrestrial Intermittent Exercise: Common Issues for Human Athletics and Comparative Animal Locomotion

The earliest studies of intermittent exercise physiology notedthat moving intermittently (i.e., alternating brief movementswith brief pauses) could transform a heavy workload into a submaximalone that can be tolerated and sustained. The brief pauses thatcharacterize intermittent locomotion permit at least partialrecovery from prior activity. This research provided the foundationfor the development of interval training and more recently forthe re-evaluation of steady-state paradigms for comparativeanimal locomotion. In this paper I review key concepts underlyingthe performance of repeated activity. I provide examples fromhuman athletics and training and comparative animal locomotion.To explore the limits of intermittent exercise performance,I examine the performance limits for continuous exercise andthe rate and extent of the recovery of performance capacityfollowing activity. While it is evident that altering locomotorbehavior (i.e., moving intermittently) can alter the capacityof an animal to perform work, mathematical models of intermittentexercise could predict strategies (i.e., exercise intensity,exercise duration, and pause duration) that will increase performancelimits for intermittent activity.     

中国菱猎蝽属厘订(半翅目：猎蝽科：真猎蝽亚科)

文中对国产的7种菱猎蝽作了比较详细的再描述与图示;短刺菱猎蝽Isyndus bre vispinus Breddin、毛翅菱猎蝽I .Lativentris Distant、毛足菱猎蝽I.Pilosipes Reuter被视为 有效种或独立种;I.Sinicus Hsiao et Ren 和I.Yunnananus Ren分别被认为是毛足菱猎蝽 I.Pilosipes Reuter和毛翅菱猎蝽I.Lativentris Distant的同物异名;短刺菱猎蝽为中国新纪录;所有种的阳茎构造均为首次报道;此外,还编制了该属中国已知种类分种检索表。     

Determination of Gardnerella vaginalis Genome Size by Pulsed-Field Gel Electrophoresis

The chromosomal DNA of four strains of Gardnerella vaginaliswere digested with rare cutting restriction enzymes and analyzedby pulsed-field gel electrophoresis (PFGE). The four strainsstudied were two clinical isolates (GVP 004 & GVP 007) andtwo American Type Culture Collection strains (ATCC 14018 &ATCC 14019). The restriction enzyme SfiI generated two DNA fragmentsof about 0.6 Mb and 1.1 Mb in all four strains giving a G. vaginalisgenome size of about 1.7 Mb. A similar genome size was calculatedutilizing two more GC-rich sequence specific restriction endonucleases,NotI and AscI. When digested with AscI, the chromosomal DNAof all four strains gave rise to 11 to 12 DNA fragments rangingbetween 0.01 Mb to 0.43 Mb. DNA from the two clinical isolateswere digested by NotI (yielding 7 to 9 fragments), while theDNA from the two ATCC strains were resistant to NotI digestion.In contrast to the clinical isolates, DNA from the two ATCCstrains gave an identical profile for all restriction endonucleasestested. From double digestion experiments, the two SfiI sitescould be localized on two AscI fragments. From these PFGE studies,it is concluded that the G. vaginalis genome is a circular DNAthat ranges between 1.67 Mb and 1.72 Mb in size.     

Pollinator Specificity and Convergence in Fly-pollinated Pleurothallis(Orchidaceae) Species: A Multiple Population Approach

We studied the floral biology of 12 populations of five rupicolousPleurothallis(Orchidaceae) species occurring in campo rupestre vegetationat nine localities in Brazil. All of these species are pollinatedby flies belonging to the families Chloropidae and Phoridae.In the five Pleurothallis species studied, all conspecific populationsattracted the same pollinator species. All pollinators werefemales; they laid eggs in flowers of the two nectarless species,but never in the flowers of nectar-presenting species. The twopairs ofPleurothallis species with similar flower morphologiesand odours attracted the same pollinators: P. johannensis -P. fabiobarrosii, pollinated by Tricimba sp. (Chloropidae) andP. teres - P. ochreata pollinated by Megaselia spp. (Phoridae).There was no overlap in the distribution of thePleurothallisspecies that shared pollinators. Despite similarities in floralmorphology and odour, genetic data show that these species pairsare not each other's closest relatives. We hypothesize thatthese similarities are due to convergence in allopatric speciesthat evolved similar pollination mechanisms. Conversely, thereare reasons to believe that adaptation to different pollinationmechanisms occurred in the closely related species P. johannensisand P. teres.Copyright 2001 Annals of Botany Company Pleurothallis, Orchidaceae, floral biology, fly-pollination, Chloropidae, Phoridae, pollinator specificity, campo rupestre     

林氏果蝇线粒体DNA分析

本文对Tamura(1988)提纯mtDNA的方法进行改进,建立了林氏果蝇Drosophila lini 线粒体DNA大量制备的方法;对采自原产地台湾省的单雌晶系TAW3146.1的线粒体DNA用10种限制性内切酶进行了酶切,得出了林氏果蝇mtDNA的分子量大小为16.3kb;用双酶切法制作了林氏果蝇线粒体DNA酶切图谱,并与属于同一复合种组的D.Kikkawai的酶切图谱进行比较。所用的内切酶有XbaI、AvaI、EcoRV、ScaI、SacI、EcoR I、HindIII、PvuⅡ、BamHI、PstⅡ。