北京海洋馆

当今世界上最大的内陆海洋馆——北京海洋馆,于今年３月２７日隆重开幕。北京海洋馆拥有种类繁多的海洋生物,是一个以展示水族生物、重点突出展示海洋动物为主的、集科普宣传教育、旅游休闲于一体的现代化的科教旅游馆。它对青少年们普及海洋知识,增强环保意识开创了最...     

从"海洋2号"看大海

科学界对“生物圈2号”褒贬不一,但这一尝试的最重要意义是使人类知道,大自然系统难以被人工完全模拟。海洋馆尝试为海洋生物提供一个人工环境,可以类比为“海洋2号”。它告诉人们:大海是一个极其复杂的系统,人类对它的认识永远是冰山一角。这对走入21世纪开发海洋的人类,是一个重要的启示。     

“海洋2号”：北京海洋馆——从“海洋2号”看大海

科学界对“生物圈2号”褒贬不一,但这一尝试的最重要意义是使人类知道,大自然系统难以被人工完全模拟。海洋馆尝试为海洋生物提供一个人工环境,可以类比为“海洋2号”。它告诉人们：大海是一个极其复杂的系统,人类对它的认识永远是冰山一角。这对走入21世纪开发海洋的人类,是一个重要的启示。     

"海洋2号"的幕后

庞大的维生系统，为海洋馆人工模拟的海洋生态提供了保障。     

产业动向

北京将建设亚洲最大的生物产业孵化器“中国生物技术学术中心”项目开工奠基仪式近日在北京举行。该学术中心建成后将成为亚洲规模最大的生物产业孵化器。“中国生物技术学术中心”总建筑面积25万平方米,由北京国际信托投资有限公司和科技部中国生物技术发展中心联合承建。学术     

新时代中国海洋科技新作为

作为人类生存环境的重要组成部分,海洋在调节气候变化、提供可再生资源和维持生态平衡中起着举足轻重的作用。人类对海洋战略地位及其价值的认识随海洋研究、开发和保护事业的发展而不断深化。纵观漫长的历史过程,两千多年前的古罗马哲学家西塞罗就预言:“谁控制了海洋,谁就控制了世界。”而今,海洋对人类社会的重要作用和价值,已从早期的“兴渔盐”“通舟楫”等,发展成为连接世界的大通道、人类社会赖以生存发展的战略空间和资源宝库。     

海洋专家建议尽快开发“海水农业”

海洋专家建议尽快开发“海水农业”“海水农业”是指应用海洋生物技术,培育用海水直接浇灌的耐盐作物、牧草、蔬菜、油料作物等的产业。据专家测算,我国耕地面积约１８亿多亩,９０年代以来,平均每年净减３００万亩。目前,我国“淡水农业”已超负荷运转。而我国海洋国...     

动态

美国热电公司举办“发现Thermo精彩世界”活动2 0 0 4年 9月 14至 17日 ,高科技仪器研发制造企业美国热电公司(Thermo)参加了在北京举行的“第十五届多国仪器仪表展览会” ,这是Thermo第一次将其在中国的十个部门产品集体亮相 ,展示各种具有领先水平的分析、检测、测量、控制仪     

喜马拉雅鱼龙在游弋

在中生代久远的时间里,恐龙曾经是地球上最主要的居民,可是它们始终未能征服海洋,而它们的一门远亲——鱼龙却是当时海洋中的一个重要类群。本刊封底展示在读者面前的就是喜马拉雅鱼龙的生活情景。它是在无产阶级文化大革命中,我国科学工作者在世界的最高峰——珠穆朗玛峰地区的聂拉木县海拔四千八百米处发现的。     

专类园掠影

儿童植物园以植物为载体,并融植物展示、科普教育和益智游戏为一体,占地面积约1万平方米。按照“游、学、体验”的设计理念,儿童植物园分为游乐项目区、学习锻炼区和森林探索区三个区域。游乐项目区有各种色彩鲜艳、丰富有趣的游乐设施,包括木屋、蹦床、木桩阵、昆虫柱和攀爬架以及平衡网等。     

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