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1.
In his important contribution to the literature on gymnosperm phylogeny, “Basic Features of Gymnosperm Systematics and Phylogeny as Evidenced by the Fossil Record,” Meyen (1984) uses the classical comparative method of the morphologist and the “congregational” method, i.e., grouping by common characters, of the taxonomist. The latter may have led him to categorize some taxa on the basis of superficially similar, non-homologous characters because he used no apparently objective method to distinguish homoplasy. For this and other reasons, Meyen’s hypothesis of evolutionary relationship among gymnosperms cannot, at present, be accepted as any nearer the truth than several competing proposals. The major innovation of Meyen’s proposed phylogeny is the recognition of the clade, Ginkgoopsida, coordinate with Cycadopsida and Pinopsida. Ginkgoopsida encompasses Calamopityaceae, Callistophytales, Glossopteridales, Peltaspermales, Caytoniales, and Ginkgoales, among others. These taxa are considered to be related because, in Meyen’s view, they share the common character of primary platyspermy — i.e., the presumed platyspermic seed-type of the basal group, Calamopityaceae, is considered to have evolved directly from the pteridophytic condition of an ancestral form. This basis for Ginkgoopsida is weakened by the facts that no seeds have been discovered in organic connection with any calamopityacean and, except for the poorly-preserved seed-like structure,Spermolithus, all seeds that occur earlier in the geologic record than fossils of the Calamopityaceae are radiospermic. It is possible, therefore, that even if the platyspermic seed,Lyrasperma, found in association with the calamopityacean,Stenomyelon, were borne by that plant, it is secondarily platyspermic, having evolved from a radiospermic ancestor. The foundation upon which Ginkgoopsida was erected seems, therefore, to be rather tenuous. Other characters used by Meyen, both reproductive and vegetative are discussed. Some which he considers significant, are interpreted to be unimportant in denoting phylogeny, while others are interpreted to support alternative hypotheses. Meyen proposes that the Ginkgoopsida evolved from archaeopterid progymnosperms. This viewpoint seems to be based largely on his erroneous belief thatArchaeopteris was probably a seed plant that bore compound leaves. There is no definitive evidence that supports the view thatArchaeopteris bore seeds. On the other hand, there is strong evidence to support the contention thatArchaeopteris produced simple leaves (Carluccio et al., 1966; Beck, 1971), not compound leaves. Meyen’s phylogenetic proposal is based on data that can be and, in part, have been differently interpreted by others. Consequently, it deserves the careful and critical evaluation of all students of gymnosperm phylogeny.  相似文献   

2.
Meyen’s “Basic features of gymnosperm systematics and phylogeny as evidenced by the fossil record” departs from the usual Botanical Review article that provides the botanical community with a synthesis of the state of knowledge and understanding of an individual segment of botany, i.e., an interpretation of progress in a specialty for the nonspecialist. Instead, this article appears intended to challenge paleobotanists to reconsider traditional views of the interrelationships of the various gymnospermous groups and the concepts on which they were based. A classification scheme is presented which divides gymnosperms into the Ginkgoopsida, Cycadopsida and Pinopsida. These classes are based on Meyen’s analysis of the structural variation in gymnosperms and his interpretation of homologies of various organs. Too often, however, key plants are reconstructed from parts known only in association and relationships are tied to assumptions of homology that have yet to be documented. The result has value in providing a succinct summary of gymnospermous structure and variation in the different groups. It is also commendable in its attempt to explain and use concepts and terminology designed especially for gymnosperms. This critique shows that in many cases there are alternative interpretations that also fit the evidence.  相似文献   

3.
This paper introduces an integrated system of morphological concepts for gymnosperm fructifications, which does not lean upon any system existing for other higher plants. Comparative analytical treatment of all available characters of the most thoroughly studied fossil genera provided the foundation for an ordered ranking of congregations, each unit being assigned to the status of families, orders and classes. The transformation of the generative and vegetative organs has been traced along various phylogenetic branches. A new large phylogenetic branch (class Ginkgoopsida), beginning with the Lower Carboniferous Calamopityales, has been established. The lineage evolved from this order to Callistophytales and further to Peltaspermales. The family Peltaspermaceae encompasses, among others, plant types formerly regarded as ginkgoaleans. The orders Ginkgoales, Leptostrobales (Czekanowskiales) and Caytoniales evolved from the Peltaspermales. The order Arberiales (glossopterids) evidently evolved from the Calamopityales. In the lineage from Calamopityales to Ginkgoales a common seed type is conserved (platyspermic, non-cupular with two vascular bundles in the integument). Radiospermic seeds are conserved in the class Cycadopsida. In the lineage from Lagenostomales to Trigonocarpales the radially symmetrical cupule underwent modification into an integument of the same type of symmetry. The earliest Lagenostomales with the bilaterally symmetrical cupule evolved into the Cordaitanthales, where the cupule, also undergoing modification, was transformed into a bilaterally-symmetrical integument. In Cordaitanthales and their descendents the Pinales the seeds became secondarily platyspermic (in contrast to the primary non-cupular and primary platyspermic seeds in Ginkgoopsida); their vascularization was progressively reduced. These two orders are grouped into the class Pinopsida. It is believed that angiosperm seeds are in effect radiospermic with a radial cupule, their vascularization also being progressively reduced. If this holds true, the angiosperm ancestry should be sought in the class Cycadopsida. The Caytoniales, Arberiales, Peltaspermales, Leptostrobales and other orders of the class Ginkgoopsida should be excluded from the stock of probable angiosperm ancestors. A new gymnosperm phylogeny has been proposed and the evolution of the phylogenetic branches outlined in terms of the phytochoria system of the geological past. The basic evolutionary innovations took place within the Equatorial Belt and adjacent ecotone areas. Three types of processes, often underrated, have a paramount role in gymnosperm phylogeny. They are defined as follows: (1) homoeotic transformations of organs; corresponding to them are heterotopies, in the morphological aspect, and saltations, in the evolutionary sense; (2) dedifferentiation of the organs (the shift of one ontogenetic program onto various organs); (3) transitive polymorphism (conservation in diversity of a certain organ during phylogeny). These processes probably serve to indicate that rearrangement in the functions of the regulatory genes played an important role in the evolution of gymnosperms.  相似文献   

4.
Living gymnosperms comprise four major groups: cycads, Ginkgo, conifers, and gnetophytes. Relationships among/within these lineages have not been fully resolved. Next generation sequencing has made available a large number of sequences, including both plastomes and single-copy nuclear genes, for reconstruction of solid phylogenetic trees. Recent advances in gymnosperm phylogenomic studies have updated our knowledge of gymnosperm systematics. Here, we review major advances of gymnosperm phylogeny over the past 10 years and propose an updated classification of extant gymnosperms. This new classification includes three classes (Cycadopsida, Ginkgoopsida, and Pinopsida), five subclasses (Cycadidae, Ginkgoidae, Cupressidae, Pinidae, and Gnetidae), eight orders (Cycadales, Ginkgoales, Araucariales, Cupressales, Pinales, Ephedrales, Gnetales, and Welwitschiales), 13 families, and 86 genera. We also described six new tribes including Acmopyleae Y. Yang, Austrocedreae Y. Yang, Chamaecyparideae Y. Yang, Microcachrydeae Y. Yang, Papuacedreae Y. Yang, and Prumnopityeae Y. Yang, and made 27 new combinations in the genus Sabina.  相似文献   

5.
Charles Taylor’s A Secular Age generated a great deal of attention—and has stimulated important debates—among a diverse range of scholars in sociology, history, politics, religious studies and to a lesser extent, anthropologists. Much of the debate has focused on the implications of Taylor’s work for the so‐called secularisation thesis and the place (or non‐place) of religion in the so‐called public sphere. The essays in this volume arise less out of such concerns and more from Taylor’s discussion of secularism in a third, ‘experiential’ sense. Each paper addresses the question of what it is like to ‘believe’ (or not ‘believe’) in the modern world. Among other things the authors of the essays published in this Special Issue are concerned to develop better understandings of the conditions under which belief and unbelief may be experienced as open, rather than closed, to the possibility of other ontological construals, thereby building on Taylor’s insights into the phenomenology of modern secularism.  相似文献   

6.
This paper explores two different views about common sense—those of Clifford Geertz and Antonio Gramsci. It examines their presuppositions, assesses their utility for archaeologists, and considers the implications of current common-sense explanations of the past. It points out that common sense is both historical. Yesterday’s common sense sometimes morphs into today’s good sense or scientific truth. Today’s common sense or scientific truth often becomes tomorrow’s false consciousness or folklore. Common sense is also relational. Groups with different positionalities in hierarchically organized societies may have widely divergent views about what is common sense. Finally, it raises the question of why particular “common sense” explanations of the present—buttressed with claims that they are rooted historically in a fixed, unchanging human nature and morality—are repeatedly resurrected by fundamentalists and conservatives in both hemispheres to justify political arguments and to reassert or impose or particular power relations.  相似文献   

7.
In this paper, I respond to arguments proposed by Brunnander in this journal issue concerning my position regarding the Creative View of natural selection (Razeto-Barry & Frick, 2011). Brunnander argues that (i) the Creative View we defend does not serve to answer William Paley’s question because (ii) Paley’s question is “why there are complex things rather than simple ones” and (iii) natural selection cannot answer this question. Brunnander’s arguments for (iii) defend a Non-creative View of natural selection (sensu Razeto-Barry & Frick, 2011). Here I claim that Brunnander’s arguments for (iii) are mistaken and I also argue that even accepting (iii) we do not have to accept (i), given that statement (ii) is historically and conceptually flawed. Thus here I analyze Paley’s question from a historical point of view and from a contemporary perspective in a quest for the potential conceptual relevance of Paley’s question today. In this vein I argue that from a contemporary point of view statement (iii) may be correct but for different reasons than those adduced by Brunnander.  相似文献   

8.
The present paper deals with the tools that can be used to represent causation and to reason about it and, specifically, with their diversity. It focuses on so-called “causal probabilities”—that is, probabilities of effects given one of their causes—and critically surveys a recent paper in which Joyce (2010) argues that the values of these probabilities do not depend on one’s conception of causation. I first establish a stronger independence claim: I show that the very definition of causal probabilities is independent of one’s conception of causation. Second, I investigate whether causal probabilities indeed take the same values under their different possible definitions.  相似文献   

9.
A methodological issue in research relating daytime mood to dream content is the question of whether mood congruency effects—that is, recalling more negative events if the current mood is more negative—also play a role in the dream recall process. This study adopted an indirect approach by testing the hypothesis that interindividual differences in mood congruency effects in a memory task carried out in the daytime correlate with mood congruency effects in dream recall (recalling more negative dream emotions, as one would predict on the basis of the current stress level or overall mood state). The findings, however, did not support the hypothesis of mood congruency effects and, thus, rule out that the findings regarding the continuity hypothesis of dreaming are biased by selective recall. Studies with different methodological approaches are necessary to validate this study’s findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

10.
In September 2000, the self-styled “anthropological journalist” Patrick Tierney began to make public his work claiming that the Yanomamö people of South America had been actively—indeed brutally—harmed by the sociobiological anthropologist Napoleon Chagnon and the geneticist-physician James Neel. Following a florid summary of Tierney’s claims by the anthropologists Terence Turner and Leslie Sponsel, the American Anthropological Association (AAA) saw fit to take Tierney’s claims seriously by conducting a major investigation into the matter. This paper focuses on the AAA’s problematic actions in this case but also provides previously unpublished information on Tierney’s falsehoods. The work presented is based on a year of research by a historian of medicine and science. The author intends the work to function as a cautionary tale to scholarly associations, which have the challenging duty of protecting scholarship and scholars from baseless and sensationalistic charges in the era of the Internet and twenty-four-hour news cycles.  相似文献   

11.
 野外条件下同时测定植物群体光合作用,呼吸作用和蒸腾作用的综合性测试装置,是为适应当前草原生态系统第一性生产力研究的需要并根据植物的光合作用、呼吸作用和蒸腾作用过程中的气体交换原理,参考国内外有关学者的类似工作而设计、组装的。该测试装置主要由人工气候箱、环境控制系统、气道系统、测试系统和电源装置五部分组成,并兼有测定环境因子的配套仪器。通过1983—1985年我们在东北天然羊草草原上实际应用的结果证明,该装置的各项测定指标均达到了预定的设计要求。本文就该测试装置的设计原理、基本结构、测试程序和计算方法等方面的问题进行了初步探讨,以便为该测试装置的不断改进和完善提供参考依据。  相似文献   

12.
The species Leptomyxa flabellata was described by Goodey in 1915 and re-isolated by Pussard and Pons in 1976. It seems that it was never seen (or never recognized) again since that time. The strain designated as “Leptomyxa flabellata CCAP 1546/2” was studied by Cann in 1984, however the quality of the electron microscopic images of that time was poor. Based on the cyst structure and size characters, Page in 1988 suggested that this strain is not co-specific with Goodey’s Leptomyxa flabellata, but represents a species ‘Ripidomyxa’ australiensis Chakraborty and Pussard, 1985, nowadays known as Rhizamoeba australiensis. In the present paper light- and electron-microscopic images of CCAP 1546/2 strain, which is now lost, are provided. Based on the morphological evidences it is suggested to establish it in a rank of a new species, Leptomyxa ambigua n. sp. Neither “true” L. flabellata Goodey, 1915 nor original R. australiensis Chakraborty et Pussard, 1985 are nowadays represented in the culture collections, and no original type material is available on both these species.  相似文献   

13.
European Union (EU) Member States have agreed to limit their greenhouse gas (GHG) emissions from sectors not covered by the EU Emissions Trading Scheme, including emissions from agricultural sector. The aggregated GHG emission rate (i.e. t CO2 eq. from agricultural sector per country) is commonly used to measure the overall size of agriculture’s influence on climate. And indeed, since 2005, EU has managed to decrease its aggregated GHG emissions by 3.1%. However, the question is—does that mean that EU’s agriculture has become less emission intensive? This paper answers the question by providing a different perspective for the assessment and comparison of the agricultural GHG emissions in 28 EU Member States. It is done by applying three different approaches, including creation of derived indicators and application of multi-criteria analysis (TOPSIS), which is a novel approach for comparison of agricultural GHG emission mitigation performance. The results show that each EU Member State performs very differently in emission intensities. Even more, the emission intensity results show an alarming tendency of increase in most of the EU Member States, which indicates that the measured changes in aggregate agricultural GHG emission rates are misleading. Therefore, the paper suggests reconsidering the policy targets for GHG emission limits.  相似文献   

14.
The Middle Ordovician Harding Sandstone in Colorado, U.S.A. is the oldest formation known to have an environment rich in vertebrate fossils. In order to study the palaeoecology of these oldest vertebrates, a detailed analysis of both the sediments and the associated invertebrate fauna was made. Undulatory quartz, sandstone mineralogy, geochemistry, trace fossils, and ecological implications of the invertebrate fossils have been studied. The type of environment is not a typical one, but was probably a shallow-water marine (intertidal, or shallow subtidal), in a lagoon-like or estuarine—deltaic habitat, with changing salinity, and a generally warm climate.  相似文献   

15.
Gümüş BA  Neubert E 《ZooKeys》2012,(171):17-37
This paper reports on results of several collecting trips of the authors in Turkey. In the course of this research, a long-lasting question was addressed. It could be proven that the nominal species Bulimus frivaldskyi L. Pfeiffer, 1847 is closely related to Meijeriella canaliculata Bank, 1985, and thus this species is shifted from the genus Ena Turton, 1831, to the genus Meijeriella Bank, 1985. Meijeriella canaliculata Bank, 1985, could be recorded from Turkey for the first time. The nomenclatural situation of the species Euchondrus septemdentatus (Roth, 1839) vs. its replacement name Euchondrus borealis (Mousson, 1874) is discussed. A new arrangement of the species formely comprised in the genus Zebrina Held, 1837 is presented, and the genera Rhabdoena Kobelt & Moellendorff, 1902, and Leucomastus A. Wagner, 1927 are re-established. The following species and subspecies new to science could be described: Vitrea gosteliisp. n. (Pristilomatidae), Turanena demirsoyisp. n., Euchondrus paucidentatussp. n., Rhabdoena gosteliisp. n. (all Enidae), Metafruticicola kizildagensissp. n. (Hygromiidae), and Assyriella thospitis menkhorstissp. n. (Helicidae). For several other species, new distribution records are listed.  相似文献   

16.
In the early twentieth century, the body was seen as both an ontogenetic and a phylogenetic entity. In the former case, its individual development, it was manifestly changeable, developing from embryo to maturity and thence to a state of decay. But in the latter case, concerning its development as a species, the question was an open one. Was its phylogenetic nature a stationary snapshot of the slow process of evolution, or was this too mutable? Historians have emphasised that the question of acquired inheritance remained open into the twentieth century; this paper explores how various constructions of the individual as a phylogenetic episode—a stage in the race’s evolution—related to representations of the body in the same period.A discussion of the work of the brothers Josef and Karel Čapek offers a contextualised answer to the question of bodily representation. Karel Čapek (1890–1938) explored the nature of the ‘average man’ through two different organisms, the robot and the amphibian, epitomes respectively of corporeal permanence and plasticity. Josef Čapek (1887–1945), along with other members of the Group of Plastic Artists, explored visual representations of the body that challenged cubist Bergsonian norms. In so doing, he affirmed what his brother also held: that despite the constrictions imposed by the oppressive political conditions in which the Czechs found themselves, the individual body was a fragile but fluid entity, capable of effecting change upon the future evolution of humankind.  相似文献   

17.
《Plains anthropologist》2013,58(86):309-328
Abstract

Seriation, a unidimensional ordering technique, is one of archaeology’s oldest and most useful tools. Its mathematical aspects have drawn the attention of mathematicians and statisticians in recent years, even as archaeologists themselves have begun to question its underlying assumptions. In this paper I describe some techniques appropriate at each step in the mathematical seriation problem: discovering trendsensitive variables and ordering items on the basis of these variables.  相似文献   

18.
This research tests the hypothesis that change over time in women’s status leads to improvements in their children’s health. Specifically, we examine whether change in resources and empowerment in mother’s roles as biological mothers, caregivers, and providers and social contexts that promote the rights and representation of and investment in women are associated with better nutritional status and survival of young children. Analysis is based on a broad sample of countries (n = 28), with data at two or more points in time to enable examination of change. Key indicators of child health show improvement in the last 13 years in developing nations. Much of this improvement—90 percent of the increase in nutritional status and 47 percent of the reduction in mortality—is associated with improving status of women. Increased maternal education, control over reproduction, freedom from violence, access to health care, legislation and enforcement of women’s rights, greater political representation, equality in the education system, and lower maternal mortality are improving children’s health. These results imply that further advancement of women’s position in society would be beneficial.  相似文献   

19.
Applying C to soils has been proposed as a plant community restoration tactic because it has been shown to immobilize inorganic N, which should confer a competitive advantage to slower growing plants that are often key components of the desired plant community. Disparate experimental and survey results have led to questions about the appropriate quality and quantity of C to apply. We conducted a single‐season glasshouse experiment in three soil types to determine how the quality (sugar, sawdust, sugar + sawdust), quantity (1 and 5 kg sugar or sawdust/m2), and mode of application (surface applied or mixed into soil) of C affected soil inorganic N pools, net mineralization rates, and aboveground biomass of coexisting C3 and C4 plant species. Carbon applied as sawdust mixed into the soil resulted in the highest level of immobilization in the short term (6 weeks), but all combinations and rates of sugar and sawdust application resulted in immobilization over this period. In the long term (24 weeks), most amendments immobilized N and suppressed aboveground biomass of the C3 grass, Bromus inermis, but the high rate of sugar resulted in the strongest immobilization and C3 suppression. However, this treatment also maintained the highest soil inorganic N pool at season’s end, which calls into question its effectiveness if longer‐term benefits are desired. Neither net mineralization rates nor soil inorganic N pools were correlated to the ratio of C4 to C3 plant biomass at season’s end indicating that the mechanisms for favorable plant response to C addition are not understood.  相似文献   

20.
中国汉族儿童少年身高发育城乡差别的变化趋势   总被引:4,自引:1,他引:3  
张迎修 《人类学学报》1999,18(4):307-310
本文分析了1985—1995年中国26个省市7—18岁城乡儿童少年身高的发育趋势。总体上看 ,城乡差别明显缩小 ,男女生 7—18岁平均缩小0.55cm和0.64cm,其中以青春发育突增期缩小幅度最大。各省市的变化趋势不一致 ,南方省市缩小较北方明显。  相似文献   

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