共查询到19条相似文献，搜索用时 218 毫秒
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数值分类在我国昆虫分类工作中的应用 总被引：9，自引：0，他引：9
数值分类学是借数值方法根据其性状状态将分类单位归类成类元,其核心就是将所有的分类性状加以等权处理,再以性状间的相似性来进行归类。国际上关于数值分类的工作开始于二十世纪五十年代,并于六十年代初趋于成熟;同时,数值分类学的方法也开始引入我国,七十年代中期数值分类首先应用到微生物和昆虫的分类中。第一篇昆虫数值分类的文章是关于蚜虫的研究,随后数值分类的方法被应用到不同类群和阶元的分类研究;进入九十年代以后,一个显著的特点是数值分类的方法与分子生物学密切结合,为昆虫不同的种群和种及种以上阶元在分子水平上精确分类开辟了新的途径。 相似文献
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分类是认识客观事物的手段,也是科学研究中一个非常重要的基本方法,例如对森林生态学调查的资料进行分类,就可以简化大量的原始资料,并可从中揭示出有生态意义的规律。过去人们主要靠经验和专业知识进行分类。在林业领域内诸如立地条件、森林生物、种子、苗木、林分、林主付产品都有分类。由于生产技术和科学的发展,分类越来越细致,分类所依据的指标也越来越多,因而只凭经验和专业知识往往不能确切分类。直到本世纪40年代以后,电子计算机的发明,多元统计数学的发展,生物分类学迫切谋求在方法上的改进,数量分类学则应运而生。聚类分析则是其中常用的一种。顾名思义,聚类分类其目的在于将一些事物根据其属性指标数据所片映的相似或接近的程度行进分类,即所谓物以类聚,使同类事物尽量相似,而类与类之间则尽量相异。聚类分析作为一种多元统计方法应用于林学领域,国内外均有不少报导。 相似文献
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第二讲物种概念与植物分类学物种是生物分类的基本单位。尽管从林奈到现在已描述和分类的生物有4、5百万种之多,种子植物也有24万种,但意味深长的是,有关物种的概念和定义的讨论已延续了200年,至今尚未统一。正因为物种缺乏 相似文献
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介绍系统发育的概念及目标。分子系统学是研究系统发育的重要方法,其理论基础来源于系统学、分类学、比较生物化学、分子生物学和进化论,是基于分子水平上的比较建立分子进化树。目前构建分子系统树的方法有最大简约法、距离矩阵法、最大似然法3种,用于系统分析的计算机软件有多序列对位排列软件和系统演化与进化分析软件。 相似文献
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Many thrips are pests of commercial crops due to the damage they cause by feeding on developing flowers or vegetables. Thrips
may also serve as vectors for plant diseases, such as tospoviruses. Their small size and predisposition towards enclosed places
makes them difficult to detect by phytosanitary inspection. In this review, several methods available for identifying thrips,
including their advantages and disadvantages, are discussed. A combination of different methods gives the most reliable identification.
Relatively new morphometric, molecular and biochemical methods for identifying thrips species represent valuable alternatives
for situations in which correct identification with classical morphological methods is very difficult, time consuming or virtually
impossible. However, traditional morphological methods should not be neglected, especially because adequate identification
using morphological keys is usually an indispensable first step in the development and validation of these new modern methods.
In addition, modern systems may still require specimen identification to the genus level via morphological keys, or such keys
may be recommended to confirm the results of modern identification methods. 相似文献
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猕猴桃遗传育种及其产业化进展 总被引：1，自引：0，他引：1
对原产中国的猕猴桃遗传资源多样性的分子生物学鉴定、新品种选育技术、耐贮性生理生化特征以及商品化开发进展等进行了综述,可供从事猕猴桃的科研工作者参考。 相似文献
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《Forest Ecology and Management》2005,209(3):207-224
An electronic aroma detection (EAD) technology known as conductive polymer analysis (CPA) was evaluated as a means of identifying and discriminating woody samples of angiosperms and gymnosperms using an analytical instrument (electronic nose) that characterizes the aroma profiles of volatiles released from excised wood into sampled headspace. The instrument measures electrical-resistance changes generated by adsorption of volatiles to the surface of electroactive, polymer-coated sensors. Unique digital electronic fingerprints of wood aromas, derived from multisensor-responses to distinct mixtures of wood volatiles, were obtained from woods of individual tree species. A reference library containing aroma signature patterns for 23 tree species was constructed for identifications of unknown samples using pattern-recognition algorithms. The 32-sensor array used with an Aromascan A32S instrument was sensitive to a wide diversity of organic compounds and produced outputs of distinct electronic aroma signature patterns in response to wood volatiles that effectively identified unknown samples from individual tree species included in the reference library. Some potential applications of CPA methods for research in ecology, forestry, plant taxonomy, and related disciplines were identified with some significant advantages and limitations. Other applications of this technology were discovered for the management of forested stands and ecosystems based on the identification of roles that wood-inhabiting organisms play in stand dynamics and long-term ecosystem functions. Results pertaining to tree systematics and phylogeny are discussed in the context of prevailing opinions of oak taxonomy. 相似文献
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介绍了目前在昆虫分类鉴定中常用的分子生物学技术,包括分子杂交技术、PCR技术、RFLP技术、RAPD技术,SSCP和DSCP技术、DNA条形码。结合自身工作,对分子生物学昆虫鉴定方法在植保中的应用前景进行了阐述。 相似文献
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Intercultural studies about the methods of use and perceptions of traditional remedies in Europe are strategically important in understanding how pharmaceutical means in our multicultural modern societies are differently accepted by diverse ethnic groups. In this survey, we analysed the biological means traditionally used in the ethnomedicine of three Arb?resh? (ethnic Albanians) communities in the Vulture area (northern Lucania, southern Italy). The majority of remedies are represented by plants belonging to 54 botanical taxa. A few of the recorded species have a traditional therapeutic use that has never previously been reported in southern Italy. Other means-especially used in the past-are comprised of mineral, animal and industrial derived materials. In specific cases, some of these materials and even plants are neither applied externally or internally, but are instead utilised as symbolic ritual objects in spiritual healing ceremonies. Ethnopharmacological and anthropological considerations about these usages are discussed. 相似文献