What Do Secondary Students Really Learn during Investigations with Living Animals? Parameters for Effective Learning with Social Insects

Exemplary for social insects, Temnothorax ants allow for various hands-on investigations in biology classes. The aim of this study was to provide a quantitative and qualitative analysis of secondary school students’ learning achievement after teaching units with ants lasting between one and six weeks. The questionnaires included transfer and factual knowledge tasks divided into eight fields of knowledge. Students (N = 459) from 22 classes participated in the study and received different treatments: The experimental group (n = 366) started their investigations by initial observation using stereo microscopes, while the control group (n = 93) conducted ant research without this introductory teaching unit. We investigated the influence of class level, gender and time period of participation on knowledge acquisition. Independent of class level, factual learning achievement was observed for all fields of knowledge except ecology. We did not find a positive correlation between time period of participation and basic ant knowledge acquisition. The findings suggest that ant research may be implemented within the framework of a progressive curriculum for all secondary school students. However, attentive and detailed observation of ant colonies with stereo microscopes and continuous repetition of technical terms seem to be inevitable preconditions for learning achievement.     

饲养条件下非人灵长类的营养需求

非人灵长类的营养学研究越来越受到国际和国内社会的关注。我国是世界上实验灵长类动物的最大产出国。进一步了解和发展非人灵长类营养学将有利于提高我国非人灵长类的饲养水平和饲料资源的利用效率,推动整体产业的发展。为此本文介绍了近年来国际上非人灵长类营养学方面的研究进展和国家饲料配比的相关规定,阐述了各营养成分的作用、缺乏症状和改善案例。旨在丰富相关方面的科学信息,增加对非人灵长类营养
需求的理解。     

湖北星斗山自然保护区国家重点保护野生植物调查研究

据调查统计,湖北星斗山自然保护区共有国家级保护植物33种,其中I级保护植物8种,Ⅱ级保护植物25种。本文分析这些植物的分布现状及特点,提出相应的保护对策。     

Cr^6＋对莼菜冬芽叶片急性毒害与保护酶系活性变化关系的研究

研究了Ｃｒ＾６＋的急性毒害对莼菜冬芽叶片的伤害程度和可溶性蛋白质、ＳＯＤ、ＣＡＴ、ＰＯＤ活性和ＭＤＡ含量变化之间的关系。在以０．５ｍｍｏｌ／Ｌ￣２．０ｍｍｏｌ／Ｌ浓度的Ｃｒ＾６＋处理时,冬芽叶片受害的程序明显地与处理浓度和处理时间呈正相关;可溶性蛋白质只在处理４ｄ时出现较大变化,其含量随处理浓度的提高而急剧增加;随着处理浓度的增加,ＳＯＤ、ＣＡＴ和ＰＯＤ的活性峰出现的时间不断后推,并且ＰＯＤ的活性     

八大公山自然保护区森林土壤动物群落多样性的初步研究

对八大公山自然保护区森林土壤动物群落的多样性进行了初步研究,共获得２７类土壤动物,隶属５门１２纲,其中螨类、弹尾类、线虫类和线蚓类为优势类群,占全捕量的８８．６７％,是该区土壤动物的主体。土壤动物密度与土壤类型和土壤性质有一定的关系,主要土壤类型层中动物密度为：黑色石灰土中１２５．６万个／,棕色石灰土中１０４．３万个／ｍ＾３,山地生草黄棕壤中９１．３万个／ｍ＾３,山地黄棕壤中７４．２万个／ｍ＾３。     

The late Pleistocene cultures of South America

Important to an understanding of the first peopling of any continent is an understanding of human dispersion and adaptation and their archeological signatures. Until recently, the earliest archeological record of South America was viewed uncritically as a uniform and unilinear development involving the intrusion of North American people who brought a founding cultural heritage, the fluted Clovis stone tool technology, and a big-game hunting tradition to the southern hemisphere between 11,000 and 10,000 years ago.^1–3 Biases in the history of research and the agendas pursued in the archeology of the first Americans have played a major part in forming this perspective.^4–6 Despite enthusiastic acceptance of the Clovis model by a vast majority of archeologists, several South American specialists have rejected it.^6–11 They contend that the presence of archeological sites in Tierra del Fuego and other regions by at least 11,000 to 10,500 years ago was simply insufficient time for even the fastest migration of North Americans to reach within only a few hundred years. Despite this concern, and despite the discovery of several pre-Clovis sites in South America,^6,10–12 some specialists^2,3 keep the Clovis model alive. Proponents of the model claim that the pre-Clovis sites are unreliable due to questionable radiocarbon dates, artifacts, and stratigraphy. Solid evidence at the Monte Verde site in Chile^14–16 and other localities^6,8,10–12 now indicates that South America was discovered by humans at least 12,500 years ago. How much earlier than 12,500 years ago is still a matter of conjecture.^6,10,12,15 Some proponents prefer a long chronology of 20,000 to 45,000 years ago,⁸ while others advocate a short chronology of 15,000 to 20,000 years ago^10–12 or only 11,000 years ago.^1–3. © 1999 Wiley-Liss, Inc.     

Cannibalism and protective behavior of eggs in Arctic charr (Salvelinus alpinus)

From video recordings of spawning events, we quantified protective and cannibalistic behavior of Arctic charr occurring immediately after spawning. The number of fish cannibalizing on stray eggs was examined regarding (a) whether more than one male shed milt during the spawning event, that is, whether sperm competition occurred, (b) whether the sperm competition included few or many males, that is, the intensity of sperm competition, and (c) the density of fish at the spawning site. Response behavior toward egg cannibalism was also examined among females and dominant males in order to determine any parental investment toward protecting the eggs after spawning. Cannibalistic behavior was seen in almost 50% of the spawnings, and the multiple spawning events showed the highest numbers of fish cannibalizing on eggs. Both the number of males releasing milt and the number of fish approaching the spawning site were positively correlated with egg cannibalism. Sperm competition was, however, not a prerequisite for egg cannibalism. Although we also observed partial filial cannibalism, protective behavior of eggs was seen both among dominant males and females, suggesting that charr actually conduct parental care.     

不同生育期花生渗透调节物质含量和抗氧化酶活性对土壤水分的响应

通过防雨棚池栽试验,以不同花生品种为试材,研究了不同生育时期非充分灌溉对花生品种各生育期叶片膜脂过氧化、渗透调节物质含量和抗氧化酶活性的影响.结果表明,苗期和花针期灌水,叶片抗氧化酶活性、渗透调节物质和丙二醛(MDA)含量均有不同程度的降低.随生育期推进和土壤水分降低,其活性升高,但升幅因品种、抗氧化酶和渗透调节物质类型有异,两品种叶片超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、可溶性糖(SS)、可溶性蛋白质(Pr)、游离氨基酸(AA)和脯氨酸(Pro)含量均以对水分最为敏感的花针期升幅较大,且花育27号的SOD、CAT、Pr和AA的升幅大于花育20号;结荚期灌水后,各抗氧化酶和渗透调节物质未表现降低.两品种全生育期灌水处理与苗期灌水处理间的抗氧化酶活性、渗透调节物质和MDA含量差异均不显著.水分胁迫初期,抗氧化酶活性升高,但随胁迫时间延长其活性明显降低;而渗透调节物质和MDA含量显著高于各生育期灌水处理.POD活性变化对灌水处理响应较弱,SOD和CAT是花生适应土壤水逆境的主要保护酶.灌水处理对花生叶片抗氧化及渗透调节能力表现为花针期＞结荚期＞苗期,各渗透物质调节能力依次表现为脯氨酸、可溶性蛋白质＞可溶性糖＞游离氨基酸.     

不同钙素水平对厚皮甜瓜叶片光合作用和保护酶活性的影响

采用深液流无土栽培方式,研究不同钙素水平对厚皮甜瓜叶片光合作用和保护酶活性的影响。结果表明,在缺钙、低钙、高钙胁迫下,厚皮甜瓜叶片中的叶绿素和类胡萝卜素含量明显下降,叶绿素a/叶绿素b比值升高;同时叶片中的超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)的活性及丙二醛(MAD)含量、相对电导率、可溶性蛋白质含量都明显高于正常供钙的植株。缺钙胁迫下,基础荧光(Fo)下降,低钙和高钙胁迫下Fo 升高,但缺钙、低钙、高钙胁迫下叶片叶绿素荧光参数Fv/Fm、Fv/Fo、Fm、Yield和ETR都明显下降。缺钙胁迫下叶片净光合速率(Pn)、气孔导度(Gs)下降,胞间 CO2 浓度(Ci)升高;而高钙胁迫下 Pn、Gs 下降的同时,Ci 也相应下降,表明缺钙胁迫下的光合抑制主要是由于非气孔限制引起,而高钙胁迫下的光合抑制主要是由于气孔限制引起。