冬虫夏草,让人们疯狂还是哭泣？

青藏高原是世界上最高、最大也是最年轻的高原,平均海拔高度在4000米以上,素有“世界屋脊”和“世界第三极”之称。高原上的皑皑白雪和巨大冰川孕育了许多中国乃至世界上著名的湖泊,还是亚洲大部分主要河流的源头所在地。沿着318国道的川藏线穿行在青藏高原上,一路上见到的都是“错”：世界上海拔最高的咸水湖纳木错,     

青藏高原上的神奇生命

<正>对青藏高原的研究已有十多年了,每次科考之旅,我们都还是那样热血沸腾,深深地感受着高原上生命世界的神奇,领悟着大自然万物生长的奥秘。青藏高原的神奇首先源于其地球"第三极"的地理地位,即相对于北极和南极,她是世界上海拔最高和面积最大的高原。这里的平均海拔在4000米以上,总面积大约250万平方公里,拥有着世界第一和第二     

最新研究发现北极狐500万年前起源于青藏高原

正青藏高原拥有在北极和南极圈之外地球上最大面积的冻土和冰川,也被称为"世界第三极"。生活在青藏高原高寒地带的哺乳动物与南北极动物同样拥有适应低温的厚重皮毛,而且其中的食肉类也较其他地区具有更强的猎食性。在西藏札达古动物群被报道之前,普遍认为现生的北极圈哺乳动物起源于广袤的全北区(即北回归线以北的北半球大部分地区)。然而,中     

全球变化背景下的高寒生态过程

正青藏高原是世界上海拔最高和面积最大的高原,被誉为"地球第三极"(姚檀栋等,2017),也是我国重要的生态安全屏障和战略资源储备基地(孙鸿烈等,2012)。高原气候整体上呈现"寒""旱"特征,且存在自东南向西北逐渐降低的降水梯度。沿着这一降水梯度,分布着森林、灌丛、高寒草甸、高寒草原和高寒荒漠等植被类型(张宪洲等,2015)。同时,该地区孕育了约占我国国土面积1/6的冻土(周幼吴等,     

青藏高原:鸟类演化的“高地”

素有"世界屋脊"、"地球第三极"之称的青藏高原,不仅是我国乃至世界的气候调节器、东南亚地区的"江河源"、"生态源",而且由于具备世界上独特的生态系统,被认为是全球山地生物物种一个重要的起源和分化中心。高原独特复杂的地理气候,保存了特有的珍稀野生动植物物种,构成相对完整的特殊生态系统,具有极高的生态价值和科学     

横断山的杜鹃花

正中国是世界上动植物资源种类分布最多的地区之一,据不完全统计,仅种子植物就有近300科3 200属约3万种。中国不仅拥有世界上最丰富的植物区系,也是世界生物多样性的关键地区之一。我国著名植物学家俞德浚院士曾将青藏高原地区的植物资源喻为植物王国里的一顶桂冠,而横断山地区的植物资源则是嵌在这桂冠上的一颗明珠。     

世界屋脊上的宝石

被喻为“世界屋脊”的青藏高原,一向以其独特的人文和自然景观而闻名于世,是科学探险考察和生态旅游的胜地。而位于青藏高原地区的形形色色的自然保护区,又是世界屋脊上生态环境最奇特、生物资源最     

极地陆域微生物多样性研究进展

极地是指高纬度、高海拔地区,包括南极(60°S以南)、北极(60°N以北)和被称为“第三极”的青藏高原地区(平均海拔4,500 m).这些地区气温极低、养分极度贫乏,生态系统非常脆弱,对全球气候变化极为敏感,该地区生态系统一旦破坏将很难恢复.尽管极地地区自然条件恶劣,但在这些极端环境中栖息着大量微生物,是元素生物地球化学循环的主要驱动者,对极地生态系统的构建和维持具有非常重要的作用.本文综述了极地土壤、湖泊和冰川等陆域环境微生物研究进展.在这些极地环境中,目前已发现了Acidobacteria,Actinobacteria,Bacteroidetes,Cyanobacteria和Firmicutes等类群,这些微生物具有嗜盐/耐盐及耐低温等特征.我国在极地微生物生态学研究方面落后于发达国家,建议优先发展较易到达的青藏高原地区微生物生态学长期定位观测,这将有助于较快提升我国极地微生物多样性研究水平,深入了解极端生命过程及其生态学效应.     

青藏高原的“地下王国”

<正>340万年前,印度板块继续向北漂移,与亚欧板块相撞,引起了强烈的地质构造运动,形成了目前地球上海拔最高、面积最大、年代最新并在逐渐升高的一个高原——青藏高原。她的最高峰为珠穆朗玛峰,海拔为8?844.43米,藏语为"job-moglang-marib"(珠穆朗玛),意思为"大地之母"。青藏高原虽然是世界上最年轻的高原,却孕育了长江、黄河、雅鲁藏布江、恒     

青藏高原：鸟类演化的“高地”

素有“世界屋脊”、“地球第三极”之称的青藏高原，不仅是我国乃至世界的气候调节器、东南亚地区的“江河源”、“生态源”，而且由于具备世界上独特的生态系统，被认为是全球山地生物物种一个重要的起源和分化中心。     

On the origin of the Hirudinea and the demise of the Oligochaeta

The phylogenetic relationships of the Clitellata were investigated with a data set of published and new complete 18S rRNA gene sequences of 51 species representing 41 families. Sequences were aligned on the basis of a secondary structure model and analysed with maximum parsimony and maximum likelihood. In contrast to the latter method, parsimony did not recover the monophyly of Clitellata. However, a close scrutiny of the data suggested a spurious attraction between some polychaetes and clitellates. As a rule, molecular trees are closely aligned with morphology-based phylogenies. Acanthobdellida and Euhirudinea were reconciled in their traditional Hirudinea clade and were included in the Oligochaeta with the Branchiobdellida via the Lumbriculidae as a possible link between the two assemblages. While the 18S gene yielded a meaningful historical signal for determining relationships within clitellates, the exact position of Hirudinea and Branchiobdellida within oligochaetes remained unresolved. The lack of phylogenetic signal is interpreted as evidence for a rapid radiation of these taxa. The placement of Clitellata within the Polychaeta remained unresolved. The biological reality of polytomies within annelids is suggested and supports the hypothesis of an extremely ancient radiation of polychaetes and emergence of clitellates.     

On the ontogeny of the haptor and the evolution of the Monogenea

Data on the ontogeny of the posterior haptor of monogeneans were obtained from more than 150 publications and summarised. These data were plotted into diagrams showing evolutionary capacity levels based on the theory of a progressive evolution of marginal hooks, anchors and other attachment components of the posterior haptor in the Monogenea (Malmberg, 1986). 5 + 5 unhinged marginal hooks are assumed to be the most primitive monogenean haptoral condition. Thus the diagrams were founded on a 5 + 5 unhinged marginal hook evolutionary capacity level, and the evolutionary capacity levels of anchors and other haptoral attachement components were arranged according to haptoral ontogenetical sequences. In the final plotting diagram data on hosts, type of spermatozoa, oncomiracidial ciliation, sensilla pattern and protonephridial systems were also included. In this way a number of correlations were revealed. Thus, for example, the number of 5 + 5 marginal hooks correlates with the most primitive monogenean type of spermatozoon and with few sensillae, many ciliated cells and a simple protonephridial system in the oncomiracidium. On the basis of the reviewed data it is concluded that the ancient monogeneans with 5 + 5 unhinged marginal hooks were divided into two main lines, one retaining unhinged marginal hooks and the other evolving hinged marginal hooks. Both main lines have recent representatives at different marginal hook evolutionary capacity levels, i.e. monogeneans retaining a haptor with only marginal hooks. For the main line with hinged marginal hooks the name Articulon-choinea n. subclass is proposed. Members with 8 + 8 hinged marginal hooks only are here called Proanchorea n. superord. Monogeneans with unhinged marginal hooks only are here called Ananchorea n. superord. and three new families are erected for its recent members: Anonchohapteridae n. fam., Acolpentronidae n. fam. and Anacanthoridae n. fam. (with 7 + 7, 8 + 8 and 9 + 9 unhinged marginal hooks, respectively). Except for the families of Articulonchoinea (e.g. Acanthocotylidae, Gyrodactylidae, Tetraonchoididae) Bychowsky's (1957) division of the Monogenea into the Oligonchoinea and Polyonchoinea fits the proposed scheme, i.e. monogeneans with unhinged marginal hooks form one old group, the Oligonchoinea, which have 5 + 5 unhinged marginal hooks, and the other group form the Polyonchoinea, which (with the exception of the Hexabothriidae) has a greater number (7 + 7, 8 + 8 or 9 + 9) of unhinged marginal hooks. It is proposed that both these names, Oligonchoinea (sensu mihi) and Polyonchoinea (sensu mihi), will be retained on one side and Articulonchoinea placed on the other side, which reflects the early monogenean evolution. Except for the members of Ananchorea [Polyonchoinea], all members of the Oligonchoinea and Polyonchoinea have anchors, which imply that they are further evolved, i.e. have passed the 5 + 5 marginal hook evolutionary capacity level (Malmberg, 1986). There are two main types of anchors in the Monogenea: haptoral anchors, with anlages appearing in the haptor, and peduncular anchors, with anlages in the peduncle. There are two types of haptoral anchors: peripheral haptoral anchors, ontogenetically the oldest, and central haptoral anchors. Peduncular anchors, in turn, are ontogenetically younger than peripheral haptoral anchors. There may be two pairs of peduncular anchors: medial peduncular anchors, ontogentically the oldest, and lateral peduncular anchors. Only peduncular (not haptoral) anchors have anchor bars. Monogeneans with haptoral anchors are here called Mediohaptanchorea n. superord. and Laterohaptanchorea n. superord. or haptanchoreans. All oligonchoineans and the oldest polyonchoineans are haptanchoreans. Certain members of Calceostomatidae [Polyonchoinea] are the only monogeneans with both (peripheral) haptoral and peduncular anchors (one pair). These monogeneans are here called Mixanchorea n. superord. Polyonchoineans with peduncular anchors and unhinged marginal hooks are here called the Pedunculanchorea n. superord. The most primitive pedunculanchoreans have only one pair of peduncular anchors with an anchor bar, while the most advanced have both medial and lateral peduncular anchors; each pair having an anchor bar. Certain families of the Articulonchoinea, the Anchorea n. superord., also have peduncular anchors (parallel evolution): only one family, the Sundanonchidae n. fam., has both medial and lateral peduncular anchors, each anchor pair with an anchor bar. Evolutionary lines from different monogenean evolutionary capacity levels are discussed and a new system of classification for the Monogenea is proposed.In agreeing to publish this article, I recognise that its contents are controversial and contrary to generally accepted views on monogenean systematics and evolution. I have anticipated a reaction to the article by inviting senior workers in the field to comment upon it: their views will be reported in a future issue of this journal. EditorIn agreeing to publish this article, I recognise that its contents are controversial and contrary to generally accepted views on monogenean systematics and evolution. I have anticipated a reaction to the article by inviting senior workers in the field to comment upon it: their views will be reported in a future issue of this journal. Editor