关键词： 寒武纪   澄江动物群   刺胞动物   栉水母   叶足动物   古虫动物  

摘要： 自达尔文1859年在《物种起源》中提出天才的“生命之树(Tree of Life)"猜想以来,愈来愈多的形态学及分子生物学证据表明,地球上所有生命“本是同根生”,组成一棵庞大的生命谱系大树。21世纪伊始,欧美国家纷纷启动了“构建生命之树”的宏伟研究计划,致力于建立一棵完整的地球生命系统发育树,将所有现存和绝灭类群联系在一起,以阐明生命起源和进化历程、各类群生物之间的亲缘关系。生命之树由“原核生命树”、“真菌树”、“植物树”和“动物树”组成。其中,动物树之构建最受世人瞩目。西方国家对于动物树的构建依赖于现生动物的分子演化信息,而完整的动物树还需要化石的检验和补充。我国滇东地区特异埋藏的澄江动物化石宝库记载了寒武纪生命大爆发主幕的珍贵信息。澄江动物群不但延续了伊迪卡拉纪爆发的基础动物(多孔动物及双胚层的栉水母及刺胞动物)和梅树村期辐射的原口动物(三胚层较低等类群,包括环节动物、叶足动物、节肢动物、曳鳃动物、软体动物、腕足动物等),还启动了后口动物(三胚层较高等类群)的辐射演化。澄江动物群中不仅诞生了现代后口动物五大类群(棘皮类、半索类、头索类、尾索类和脊椎类)的所有早期代表,还出现一个已绝灭的后口动物原始类群——古虫动物门,标志着早期动物树已基本成型。因此,澄江动物群科学意义重大,对于早期动物谱系树的重建提供了一个绝佳的瞭望窗口。现代生物学认为,动物树主要包含三个亚界、四大类群：基础动物亚界、原口动物亚界(蜕皮类群和触手担轮类群)和后口动物亚界。基于作者对澄江动物群(二街、三街子、耳材村、马房、尖山、帽天山6个剖面)化石信息的新发现,本文不仅填补了早期动物树中部分支系的空白,而且对四大类群中一些关键节点的构建提出了新见解：1.基础动物类群：中华先光海葵的形态学新发现表明它具有纤毛滤食系统,并证实了它与刺胞动物的亲缘关系；比较生物学及分支系统学研究均表明中华先光海葵为一种干群刺胞动物；因此,这一水螅型滤食性动物可作为刺胞动物谱系的一个关键节点(最近共祖)。澄江动物群中所有栉水母(包括四个新属种)都具有矿化骨骼系统及辐射对称体制；它们可归纳入一个新纲(始栉水母纲),构成栉水母动物门的一个早期干群分枝。2.蜕皮类群：澄江叶足动物(凶猛爪网虫及具足埃舍虫等)的形态新发现指示了它们最原始的头部构型及与泛节肢动物的同源性状,揭露了早期叶足动物→现代有爪类→节肢动物头部演化模式；因此,早期叶足动物可论证为干群泛节肢动物。中间型始莱德利基虫的个体发育研究表明该三叶虫与北美的小油栉虫类和非洲的法罗特史虫类可能存在由异时发育导致的谱系演化关系,进一步证实莱德利基虫目为三叶虫纲的基干类群。3.触手担轮类群：变形廼莲虫是澄江动物群中新发现的一个珍稀物种；该生物具环绕口部的触手冠和位于体侧的前置肛门,很可能代表一种干群触手冠动物。4.后口动物类群：古虫动物的解剖学新证据进一步论证了原始咽鳃裂的存在及其适于排出咽内海水及辅助滤食／呼吸的功能,支持古虫动物为后口动物亚界的基干类群；该类群为后口动物原始体制(尤其是咽鳃裂)的起源和早期演化提供了珍贵信息。

关键词： arthropod phylogeny   anatomy   fossils   molecular data   phylogenomics  

摘要： Arthropods are the most diverse group of animals and have been so since the Cambrian radiation. They belong to the protostome clade Ecdysozoa, with Onychophora (velvet worms) as their most likely sister group and tardigrades (water bears) the next closest relative. The arthropod tree of life can be interpreted as a five-taxon network, containing Pycnogonida, Euchelicerata, Myriapoda, Crustacea, and Hexapoda, the last two forming the clade Tetraconata or Pancrustacea. The unrooted relationship of Tetraconata to the three other lineages is well established, but of three possible rooting positions the Mandibulata hypothesis receives the most support. Novel approaches to studying anatomy with noninvasive three-dimensional reconstruction techniques, the application of these techniques to new and old fossils, and the so-called next-generation sequencing techniques are at the forefront of understanding arthropod relationships. Cambrian fossils assigned to the arthropod stem group inform on the origin of arthropod characters from a lobopodian ancestry. Monophyly of Pycnogonida, Euchelicerata, Myriapoda, Tetraconata, and Hexapoda is well supported, but the interrelationships of arachnid orders and the details of crustacean paraphyly with respect to Hexapoda remain the major unsolved phylogenetic problems.

关键词： 墨尔本   澳大利亚   新西兰北岛   十字星   羊毛制品   生态游  

摘要： 2012年4月,民间环保组织绿家园组织了赴澳大利亚与新西兰的生态游。在这次生态游中,我看到了很多,也思考了很多。走进大树体内去拍照一到新西兰基督城,负责接待的当地华人殷晓雷就问我们:"要不要走进一棵大树去拍照?"走进大树?大树也能走进去吗?带着好奇,我们真的走进了大树。原来这棵树一

关键词： 动物化石   恐龙   科学家   古生物学家   古脊椎动物   美国科学院   研究所   古人类  

摘要： 古生物学家认为，鸟类是由恐龙进化来的，而且许多恐龙也是凶猛的肉食动物，那么，刚披上羽毛的恐龙能飞上树吗？近日，《美国科学院院刊》将在线发表中科院古脊椎动物与古人类研究所的最新发现：它们可以飞上树!因为它们能逮食树栖动物。

关键词： 雕塑   单簧管   北京   学习   田树民   石雕  

摘要： 田树民,1956年生,北京人,自幼随父学习绘画,尤喜动物与音乐,先拜解放军军乐团单簧管演奏家张进才学习单簧管,后从吾学习石雕。树民青年时期在北京动物园供职,与鸟兽虫鱼结下不解之缘。

关键词： 古脊椎动物   化石证据   树栖   恐龙   中国科学院   古生物学家   早白垩世   相对位置  

摘要： 中国科学院古脊椎动物与古人类研究所的周忠和发现：刚披上羽毛的恐龙可以飞上树．因为它们能逮食树栖动物。那是1.2亿年前的一只小盗龙，古生物学家在我国辽宁早白垩世的地层中发现了它的化石。在它的腹部，竟然保存了一件不完整的树栖动物残骸。从骨骼化石的保存特点和相对位置推测，该动物很可能是被小盗龙活捉了吞下肚子的。这件标本解开了一些谜团：这只已经成年的小动物残存下了两只脚，从脚趾看，属于典型的树栖类动物，

关键词： Alien herbivorous mammals   Angiosperm flora   Casuarina equisetifolia   Oceanic island   Vegetation change  

摘要： Insular ecosystems can be dramatically affected by alien species, and records of pre-eradication status are essential to evaluate the effects of eradicating alien species. Nishi-jima Island is a small island of the Ogasawara group on which the first program of complete eradication of alien herbivorous mammals (black rats and feral goats) will be conducted. After eradication, the government plans to conduct ecosystem restoration on the island. This paper reports the angiosperm flora and vegetation of Nishi-jima Island before eradication of the rats and goats, with the objective of aiding ecosystem management after the eradication. Our surveys indicate that vegetation cover by the alien tree, Casuarina equisetifolia has expanded compared with its distribution in a 1974 aerial photograph of the island. The predominant vegetation in 2006 was C. equisetifolia forests and Zoysia tenuifolia grasslands, with fragmented native tree vegetation. The flora of the island comprised 69 angiosperm species (50 indigenous species) of which 30% were endemic, far less than for the Ogasawara Islands as a whole (45%). However, several populations of endangered plants remain. To restore the native ecosystem on Nishi-jima, eradication of C. equisetifolia is important in addition to eradication of alien herbivorous mammals.

关键词： Herbivores   Fire   Savanna   State transition   Gradient  

摘要： The tree-grass co-existence in savannas involves multiple and sometimes connected biogeophysical conditions. The savanna domain, its boundaries, and transitions (gradual or abrupt) to other vegetation types (i.e., grassland or forest) are fundamental for the management of ecosystems and for preserving the biodiversity in present conditions and in future changing scenarios. Here we investigate the savanna domain within grazers-fire and browsers-fire parameter planes through a simple ecohydrological model of tree-grass-soil water dynamics. Stability maps allow to identify savanna domains and to show the behavior of vegetation under increasing pressure of grazing and browsing. Stability maps shed light on the causes behind possible vegetation abrupt transitions (e.g., forest collapse and bush encroachment). An application to 15 African savannas sites is presented and discussed with the support of a local sensitivity analysis of the model's parameters. (C) 2011 Elsevier Ltd. All rights reserved.

关键词： Acer saccharum   Eriophyoid mite   Galls   Herbivory   Ontogeny   Gas-exchange  

摘要： Mature forest canopies sustain an enormous diversity of herbivorous arthropods;however, with the exception of species that exhibit large-scale outbreaks, canopy arthropods are thought to have relatively little influence on overall forest productivity. Diminutive gall-inducing mites (Acari;Eriophyoidae) are ubiquitous in forest canopies and are almost always highly host specific, but despite their pervasive occurrence, the impacts of these obligate parasites on canopy physiology have not been examined. We have documented large declines in photosynthetic capacity (approx. 60%) and stomatal conductance (approx. 50%) in canopy leaves of mature sugar maple (Acer saccharum) trees frequently galled by the maple spindle gall mite Vasates aceriscrumena. Remarkably, such large impacts occurred at very low levels of galling, with the presence of only a few galls (occupying approx. 1% of leaf area) compromising gas-exchange across the entire leaf. In contrast to these extreme impacts on the leaves of adult trees, galls had no detectible effect on the gas-exchange of maple saplings, implying large ontogenetic differences in host tolerance to mite galling. We also found a significant negative correlation between canopy tree radial increment growth and levels of mite galling. Increased galling levels and higher physiological susceptibility in older canopy trees thus suggest that gall-inducing mites may be major drivers of "age-dependent" reductions in the physiological performance and growth of older trees.

关键词： endangered species   marsupial   mean kinship   microsatellite markers   mtDNA control region   Papua New Guinea  

摘要： Matschie's tree kangaroo (Dendrolagus matschiei) is an endangered species that has been bred in captivity since the 1970s. In 1992, the Tree Kangaroo Species Survival Plan (R) (TKSSP) was established to coordinate the captive management of Association of Zoos and Aquariums (AZA) D. matschiei. The TKSSP makes annual breeding recommendations primarily based on the mean kinship (MK) strategy. Captive breeding programs often use the MK strategy to preserve genetic diversity in small populationsto avoid the negative consequences of inbreeding and retain their adaptive potential. The ability of a captive breeding program to retain the population's genetic diversity over time can be evaluated by comparing the genetic diversity of the captive population to wild populations. We analyzed DNA extracted from blood and fecal samples from AZA (n = 71), captive (n = 28), and wild (n = 22) D. matschiei using eight microsatellite markers and sequenced the partial mitochondrial DNA control region gene. AZA D. matschiei had a similar expected heterozygosity (He = 0.595 +/- 0.184) compared with wild D. matschiei (He = 0.628 +/- 0.143), but they had different allelic frequencies (FST = 0.126;P<0.001). AZA D. matschiei haplotype diversity was almost two times lower than wild D. matschiei (). These data will assist management of AZA D. matschiei and serve as a baseline for AZA and wild D. matschiei genetic diversity values that could be used to monitor future changes in their genetic diversity. Zoo Biol 30:636646, 2011. (c) 2010 Wiley Periodicals, Inc.