探究光对河虾生活的影响

本节包含了生物学新课程的第1个探究实验，即“光对鼠妇生活的影响”，体现了新课程标准极力倡导的全新的学习理念——探究式、合作式的学习方式。因此．它的开展与否以及成功与否，均对学生以后的学习产生至关重要的影响。但是，开展课改1年来所反馈的信息却表明，该探究活动并没有得到成功的开展．原因在于——鼠妇在某些地区难找!     

“探究影响鼠妇分布的环境因素”的实验教学

从教学实践出发,对"探究影响鼠妇分布的环境因素"实验的实验材料、装置、操作细节等方面进行优化,以利于学生体验科学探究的一般过程,了解对照实验的设计要点,并尝试进行实验的设计和实施,引导学生培养认真细致、求实严谨的科学态度以及爱护生物、尊重生命的人文意识。     

改进"探究种子萌发环境条件"实验的教学设计

义务教育人教版和北师大版新教材中起始探究实验都是探究环境因素对鼠妇生活的影响,江苏版新教材中起始探究实验是蚯蚓在什么样的物体表面爬得快,由于实验动物比较难捕捉和饲养,可行性受到影响,据新课程实验区实际教学情况的不完全统计,起始探究实验的开设率较低。“探究种子萌发环境条件”实验是7年级上册“种子的萌发”一节的教学内容把教材“探究种子萌发的环境条件”改为“探究影响种子萌发的条件”。并作为7年级起始的探究实验,保证了起始探究实验的实效。     

鼠妇的捕捉与暂养

1　鼠妇的捕捉鼠妇大多喜欢生活在腐朽的木头和木板下、背阴灌丛的枯败落叶下、花瓶底下。捕捉时用一马粪纸扳 ,做成小铲状进行抄捉 (用汤匙不行 ,太小 ) ,动作要快 ,抄到后立即放入事先准备好的烧杯或做成广口的饮料瓶中。瓶底放些潮土压实 ,瓶外用有色纸包裹遮光 ,造成阴湿环境 ,令鼠妇安定。也可在一直保持潮湿、较为郁闭的背阴花坛土中 ,用水管向坛中大量灌水 ,鼠妇会因受水浸无法呼吸爬出 ,在坛壁上可用小软刷扫到大量的鼠妇。2　鼠妇的暂养班级人数较多 ,一次实验必须准备数百只鼠妇 ,捉到的鼠妇必须暂养起来 ,方法是用一黑色瓦质花瓶…     

对鼠妇摄取的食物和如何饲养鼠妇的探索

鼠妇 (Porcellio)也称西瓜虫 ,甲壳纲 ,软甲亚纲 ,等足目 [1 ] 。身体通常扁平 ,无背甲 ;胸部十分发达 ;腹部短 ,一部或全部愈合 ;腹肢双叉型。其腹部附肢的体表内陷 ,形成了与气管相似的构造 ,适于陆上的呼吸 [2 ] 。受惊扰时 ,虫体常卷曲不动。世界性种 ,我国分布也较广。鼠妇生于潮湿的土壤 ,栖息枯枝腐叶间或石块下。杂食性 ,主要摄食植物细根、嫩叶以及小型无脊椎动物的尸体 [3]。鼠妇是鱼类和家禽的饵料。进行鼠妇的饲养具有一定的经济价值。许多生物学工作者还发现 ,进行“阳光、水、温度等生态因素对生物分布的影响”生物学探究活…     

浅谈生物学教学中如何利用数据进行教学

数据是进行各种统计、计算、科学研究或技术设计等所依据的数值。综合比较原用初中《生物》教材与现用初中课程标准实验教科书《生物学》(以下简称课程标准教材 ) ,可以明显地发现 ,课程标准教材由于更注重发展学生的科学探究能力 ,因而着意安排了许多与数据有关的学习内容 ,如“光对鼠妇生活的影响”、“酸雨对种子萌发的影响”、“测定某种食物中的能量”等探究性实验 ,旨在培养学生“收集数据、评价数据、处理数据”、“通过文字描述、数字表格、示意图、曲线图等方式完成报告 ,并组织交流探究的过程和结果”的能力 ,同时要求教师 ,“应…     

鼠妇的采集和培养

介绍了一种用花生麸培养鼠妇的新方法,能够在控制的时间内培养出足够量的鼠妇．保证了实验教学的正常开展。     

第10届国际生物奥林匹克竞赛(1999)理论试题(七)

(续 2 0 0 0年第 35卷第 11期第 4 3页 )生态学97　一个学生估算一块木头下面鼠妇的种群数量。她捉了 4 0个鼠妇 ,将它们标记后放回 ,并与该种群中的其他个体混合在一起。 2 4 h后 ,她又捉了 4 0只鼠妇 ,在新捉的鼠妇中 ,只有 16只是有标记的。假定在 2 4 h内 ,鼠妇无死亡 ,没有受伤害 ,无迁入与迁出。估算鼠妇的种群数量。你估算的鼠妇的种群数量是。98　根据海岛生物地学的平衡理论 ,一个海岛上物种的数量是由灭绝物种的频率和开拓物种的频率间的平衡来决定的。该理论指出 ,海岛的面积越大 ,物种灭绝的可能越小。该理论还指出 ,海岛离大陆…     

潮虫亚目(甲壳动物亚门:等足目)二中国新纪录种

通过对山西省境内等足目进行调查研究,发现等足目潮虫亚目鼠妇科腊鼠妇属2个新纪录种,分别为多变腊鼠妇Porcellionides variabilis Jackson,1926和弗罗里达腊鼠妇Porcellionides floria Garthwaite&Sassaman,1985.多变腊鼠妇主要鉴别特征为体色各部分颜色多变,雄性第1腹肢的外肢节近鳃盖状,下端具一弧形凹陷,上端具波浪状凹刻;弗罗里达腊鼠妇主要鉴别特征为头胸部近似长方形,第7胸肢座节末端具2枚硬刺.所有检视标本保存于山西师范大学生命科学学院动物实验室.     

“非生物因素对鼠妇分布的影响”实验方案的改进

导致"非生物因素对鼠妇分布的影响"实验失误的因素有很多,就实验装置的设计、实验方法的改进及对实验失误的反思等方面进行探讨,寻找提高实验效果的办法。     

New(s) to the (Z-)ring

Cytokinesis in bacteria is mediated by a macromolecular machine known as the divisome, consisting of an assembly of FtsZ polymers around the cylindrical axis of the cell and the downstream regulators of division that are subsequently recruited to it. FtsZ polymerizes into filaments in a GTP-dependent manner, similarly to its eukaryotic structural homolog tubulin. The initial placement of the FtsZ polymerization site is tightly regulated by multiple mechanisms, as are the subsequent polymer reshaping and force generation that separate the two daughter cells from each other. New factors have been recently discovered that contribute to this regulation, notably affecting FtsZ polymer shaping, and modulating FtsZ polymerization in response to the metabolic or redox state of the cell.     

Linkage between the loci for the Lp(a) lipoprotein (LP) and plasminogen (PLG)

Summary A locus, LP, that determines quantitative variation of Lp(a) lipoprotein phenotypes is linked to the plasminogen (PLG) locus (peak lod score =12.73). This linkage relationship assigns a locus with alleles that have an affect on risk for coronary artery disease to the long arm of chromosome 6.     

(AGCTG) (AGCTG) (AGCTG) (GGGTG) as the primordial sequence of intergenic spacers: the role in immunoglobulin class switch

The means employed for immunoglobulin heavy chain class switch appears to be no different from that by which meiotic intergenic crossing-overs at accomplished. As with other intergenic spacers, the 5' noncoding sequence of each Ig CH (immunoglobulin heavy chain constant region) gene apparently undergoes unconstrained sequence changes due to randomly sustained base substitutions, deletions, and duplications. Yet, there remains sufficient regional sequence homology between the Ig Cmu 5' noncoding sequence and those of its somatic recombination partners, e.g., Ig C gamma 1, Ig C gamma 2b, Ig C alpha, because each of these 5' noncoding sequences is made of multiple copies in various stages of degeneracy of one primordial 20 base pair-long sequence: (AGCTG) (AGCTG) (AGCTG) (GGGTG).     

铁线莲属研究随记(VI)(英文)

讨论了Clematis eriopoda Maxim.和sect.Atragenopsis Boiss.的地位,认为这二分类群均应成立;描述了2新种,1新变种;过去长期被归并的卷萼铁线莲C.tubulosa得到恢复;Clematisheracleifoliavar.ichangensis被转移改作卷萼铁线莲的变种;首次给出光叶铁线莲Clematisglabrifolia的果实的形态描述。     

Mitochondria-rich cells in the astigmatic mites,Diplaegidia columbae (Buchholz) (Analgidae) and Falculifer rostratus (Buchholz) (Falculiferidae) (Acari: Astigmata)

Mitochondria are well-characterized intracellular organelles usually concentrated in locations of high energy consumption. Light microscopic and transmission electron microscopic observations of the internal anatomy of the feather mites Diplaegidia columbae and Falculifer rostratus were conducted. In the anterior half of the bodies of the mites, we found several dozen of distinctive mitochondria-rich (MR) cells filled with abundant, large mitochondria. Mitochondria are placed individually or enclosed in small groups within an elaborated lamellar system forming a mitochondria–lamellae complex (MLC). The role of the MLC as well as the MR cells is not clear at present, but their involvement in heat generation is hypothesized and briefly discussed.     

Dioecism of the genusCallicarpa (Verbenaceae) in the Bonin (Ogasawara) Islands

The morphology and function of the flowers of three species of the genusCallicarpa, C. glabra, C. nisnimurae andC. subpubescens, endemic to the Bonin Islands, revealed that all three species were dioecious. Male plants had short-styled flowers with sterile ovaries, while female plants had long-styled flowers with non-germinating inaperturate pollen grains. Such dioecism has never been reported from the family Verbenaceae. This curious sexual system with non-germinating pollen grains may have been maintained as a reward to insect pollinators.     

Lecithostaphylus retroflexus (Molin, 1859) (Zoogonidae) and Tergestia acanthocephala (Stossich, 1887) (Fellodistomidae) (Digenea) from the epipelagic teleost Belone belone (L.) in the western Mediterranean

Numerous individuals of the poorly known species Lecithostaphylus retroflexus (Zoogonidae) and Tergestia acanthocephala (Fellodistomidae) have been recovered from the teleost fish Belone belone gracilis from off the Scandola Nature Reserve, Western Mediterranean. They are redescribed, incorporating previously undescribed features: for L. retroflexus, a post-oral ring, a bipartite seminal vesicle, the shape of the excretory vesicle, the subterminal excretory pore and the flask-shaped gland-cells associated with the distinctly pedunculate ventral sucker; and for T. acanthocephala, the intestinal bifurcation in the forebody, necessitating its return to the genus Tergestia from Theledera. Additionally, T. acanthocephala is compared with T. laticollis from various species of Trachurus from the same geographical area.     

天然型与非天然型脱落酸的生物活性比较

采用新方法精制脱落酸（ＡＢＡ）异构体试样,提高了（Ｓ）－（＋）－ＡＢＡ与（Ｒ）－（－）－ＡＢＡ两对映体纯度。抑制生长试验和残留量分析以及气孔闭合试验表明：天然型（Ｓ）－（＋）－ＡＢＡ活性显著高于非天然型（Ｒ）－（－）－ＡＢＡ或（ＳＲ）－（±）－ＡＢＡ。抑制莴苣种子发芽５０％的活性强度,（Ｓ）－（＋）－ＡＢＡ约是（Ｒ）－（－）－ＡＢＡ的５倍,（ＳＲ）－（±）－ＡＢＡ介于两者之间。抑制萝卜下胚轴生长试验,最显著有效期为２～６ｄ,生理作用期约为一周,（Ｓ）－（＋）－ＡＢＡ活性是（Ｒ）－（一）－ＡＢＡ的３．５倍。鸭跖革气孔闭合试验,（Ｓ）－（＋）－ＡＢＡ活性比（Ｒ）－（－）－ＡＢＡ高１倍。     

On the Knowledge of Coprophilus (Zonyptilus) pennifer (Motschulsky, 1845) and Coprophilus (Zonyptilus) marginalis (Reitter, 1894) (Coleoptera,Staphylinidae)

Entomological Review - The type and other extensive material of Coprophilus (Zonyptilus) pennifer (Motschulsky, 1845) and some of its synonyms was examined. Coprophilus (Zonyptilus) marginalis...