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Land snail faunas from maquis and phrygana sites on the islandsof Naxos and Crete, and from the eastern Peloponnese were sampledto determine the relationships between local (site) and regionaldiversities. Mean site diversities are similar in each region.In both the Peloponnese and Crete, however, these representa much lower proportion of total diversity than is the casefor forest faunas from more northerly parts of Europe. The smallisland of Naxos has more uniform faunas. Some of this between-sitediversity is a product of habitat heterogeneity, but most isa product of small-scale biogeographical differentiation. Despitethe short (c. 250km) distances between regions, the faunas ofeach region differ far more than do faunas from forests in northernEurope spread over much greater distances. Nearly 80% of speciesrecorded were found in only one region. These results are comparedwith those from elsewhere, and discussed in the context of thehigh diversity of snail faunas in the mediterranean area generally. (Received 5 May 1999; accepted 1 July 1999) 相似文献
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CALVIN H. STEVENS 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1971,4(4):403-412
Variability of marine faunas in Middle Pennsylvanian rocks in central Colorado, as generally of modern marine faunas, increases with increasing depth and distance from shore in shallow water. Less than 3 genera of brachiopods lived nearshore, whereas 10 were present in water computed to have been 22 meters deep, about 5 kilometers offshore. Foraminifers increase from 1 or 2 irregularly formed types nearshore, to 6–8 types in offshore areas, and foraminiferal density increases sharply 3l/2 kilometers offshore at a depth of about 15 meters. Several genera of brachiopods, 3 types of foraminifers, and phylloid algae show a distribution closely related to depth of water and distance from shore. On the basis of significant changes in genera of brachiopods, types of foraminifers, general faunal diversity, and foraminiferal density, three distinct biotopes can be recognized. These biotopes were occupied by the euphemitid, dictyoclostid- Composita , and fusulinid fossil communities. 相似文献
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前乐平统海洋动物灾变事件 总被引:10,自引:0,他引:10
作为古生代最后阶段的乐平统可划分为2个阶和4个亚阶,暂以逼近自然界线的Clarkina postbitteri带之底为下界;在二叠纪形成了栖霞期之前和吴家坪期之前两个超序界面,乐平世海侵居于二叠一三叠纪超序的低水位体系,乐平世末的海泛淹没了古特提斯区的残留陆棚;二叠纪末的生物大绝灭形成规模和性质不同的两幕;茅口期末全球性海退使栖居地丧失而导致地方性类群和远洋浮游生物灭亡的前乐平统海泮动物灾变事件, 相似文献
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昆虫的变态类型与分类体系 总被引:3,自引:0,他引:3
变态类型作为昆虫分类的一种根据,可说由来已久。远在林奈以前,著名自然学者史璜默邓(Swammerdam)和雷约翰(John Ray)即已根据变态现象,制订“昆虫”的分类体系;当然,那时所指的“昆虫”,几乎包括所有的节足动物和环节动物在内。林奈以后,李区(Leach,1815)、勃马斯德(Burmeister,1829,1832)和西波尔特(von Siebold,1848)都以同 相似文献
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Abstract In field control of insects with insecticides, insects could develop different degrees of resistance. When resistance data were reviewed more extensively, it was found that detoxication alone cannot explain very high resistance of house flies to OC1 (organochlorine) insecticides. As a group, flies can develop much higher resistance to OC1 than to OP (organophosphorus) insecticides. although OPs are generally less stable in insects. With the consideration of the dynamics of insect toxicology. one can readily realize the importance of penetration. Based on the rates of penetration and detoxication. slow penetration is a limiting factor for detoxication. To further explain the observed results on the control of S (susceptible) 'and R (resistant) insects, several correlation curves were plotted. on the relationship between physical and biological factors. These relationships not only indicate approximate degrees of resistance of flies to OPs and OCls, but also help select new toxicants. For example, fast speed of action index of insecticides can produce lower resistance, and the analysis of the joint action of insecticides helps evaluate the types (same or different) of mode of action for controlling resistant insects. 相似文献
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昆虫抗药性和昆虫毒理动力学(英文) 总被引:1,自引:0,他引:1
不断地使用一种杀虫药剂防治昆虫,会导致昆虫产生抗药性。对昆虫抗药性资料进行广泛综述时,发现了仅单独的解毒作用不能被解释为家蝇对有机氯杀虫药剂产生高抗性原因。作为一个基因。家蝇可以对有机氯产生比对有机磷杀虫剂更高的抗药性,尽管有机磷杀虫剂一般在虫体内是不太稳定的。考虑到昆虫毒理的动力学,杀虫药剂的穿透作用更显示出其实际的重要性。根据穿透和解毒的速率,慢的穿透作用是解毒作用的一个限制因子。防治敏感和抗性昆虫的观察结果,可以划出物理和生物因子之间关系的几种相关曲线图解。这些相关性不仅能说明家蝇对有机磷和有机氯杀虫剂的抗性程度,而且也助于选择出新的杀虫毒剂。 相似文献
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化学防治是解决害虫问题最为有效的手段之一,三十年来曾对杀虫药剂和毒理学做了不少的科学研究。据统计,《昆虫学报》发表的有关论文在第一个十年中占总篇数的9%,反映我国对害虫的化学防治在早期已有一定的基础。然而,最早试验用昆虫病原防治害虫开始于五十年代中期,对于昆虫病毒的研究开始于六十年代,所以昆虫病理学在我国的开展较晚。这两门能密切结合生产实践的昆虫学分支学科的内容和在我国发展的过程不同,宜加以分述。 相似文献
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陕西蓝田地区第四纪哺乳动物群的划分 总被引:5,自引:0,他引:5
<正> 陕西蓝田地区的新生代地层保存得非常完好,各个时代的地层,几乎都有其代表,并发现了丰富的哺乳动物化石。在第四纪地层中,特别具有意义的是公王岭及陈家窝分别发现了蓝田人头盖骨及下颌骨,一些地区还发现了旧石器,更进一步证实这一地区在第四 相似文献
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柴达木盆地石炭纪的Ting类,珊瑚和腕足动物的代表属与中国其它代表地区-塔里木盆地,准噶尔盆地,陕甘宁地区,华北地区,华南地区,西藏北部地区可以进行对比,在计算大Zong相似系数的基础上,进行Q型聚类分析,得出古生物地理分区结果,则解决柴达木盆地石炭纪古生物地理归属问题,研究结果表明,早石炭世可划分为:柴达木-华南-陕甘宁生物区;塔里木-藏北生物区和准噶尔生物区,柴达木属于柴达木-华南生物亚区,晚 相似文献
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T. H. C. TAYLOR 《The Annals of applied biology》1955,42(1):190-196
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OSMOTIC REGULATION and THE FAUNAS OF INLAND WATERS 总被引:4,自引:0,他引:4
L. C. BEADLE 《Biological reviews of the Cambridge Philosophical Society》1943,18(4):172-183
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BIOCHEMICAL IMPLICATIONS OF INSECT MYCOPHAGY 总被引:3,自引:0,他引:3
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