动物的觅食对策

觅食行为是动物最常见和最基本的行为,自然选择总是使动物在觅食过程中尽可能地增大净收益。本文采用投资-收益分析法探讨了动物的觅食对策,阐述了动物选择最有利食物、最适食谱、最有利生态小区的行为机制和生物学意义。     

浅谈转基因动物的研究进展

回顾了国内外关于转基因的研究,对转基因动物获得的主要方法如显微原核注射法、逆转录病毒感染法、胚胎干细胞介导法等常用的方法进行了综述;阐述了转基因动物的鉴定方法,最后对转基因动物在理论和实践方面的应用情况进行了综述。     

动物的利他行为

在动物界中,存在一种不惜牺牲自已利益的利他现象,其主要形式有亲缘利他、互惠利他及纯粹利他。群体选择理论、亲缘选择理论、合作进化理论和自私基因理论从不同的角度解释了动物利他行为的产生和意义。     

动物的受精

除单细胞动物以外 ,动物个体由两部分细胞组成 :不同类型的体细胞及生殖细胞。两者都是从受精卵发育而成。受精是动物个体发育的开始 ,单倍体的雌、雄生殖细胞结合 ,各自的单倍体基因组相融合形成两倍体合子 ,从而完成受精过程。不同动物精子的形状、大小和内部结构各不相同 ,主要分为两大类 :有尾类精子和无尾类精子。哺乳动物的精子属于有尾类精子 ,主要由三部分组成 :头部、颈部和尾部。头部由细胞核和顶体构成 ,其形态因动物而异 ,精子的核主要由ＤＮＡ和核蛋白组成 ;核的前面为顶体 ,顶体是一外包有单位膜的囊状结构 ,位于头部质膜与核…     

动物运动的力学分析

动物在近亿年的进化历史过程中发展了各具特色的运动能力，而且整体功能优化，为当前人造水下航行器和飞行器望尘莫及。从动物的运动力学原理中汲取新思想和新概念，仿生学迫切需要依赖于生物运动力学的强力支撑。在动物学教学中学习力学原理，有利于培养学生的兴趣，加强生物运动力学基础知识的掌握，加强学科知识的渗透学习。     

动物名词加动词构成词的分类研究

动物词作为词汇体系中相当丰富的一部分,关于它们的研究颇多,然而多集中在把它们作为一个整体的宏观研究上。事实上,动物词这一词汇类型内部也是相当丰满的,种类繁多,结构复杂,有必要对其进行更加细致微观的研究。将动物词内部的"鲸吞"、"蚕食"、"狼嚎"等动物名词加动词构成的动物词作为微观研究对象,从语用的角度将这类词进行分类,以此来分析研究这类词的特点。     

动物的行为给我们的教育启示

动物的行为可分为先天性行为和后天性行为两大类,从生物进化的角度来看,在长期自然选择作用下,动物的行为都是有利于它们的生存和种族繁衍的,但在人为控制或实验情况下,一些动物的行为会发生某种变化,给我们从事教育工作的人或多或少的启示。1毛毛虫实验———创新与生存法国昆     

Students' understandings about animal skeletons

Surprisingly few studies have looked at people's understanding of skeletons. Most of the work in this field that has been done has only involved children's understanding of human skeletons. This study looks at students' understandings of the structure of animal (including human) skeletons. A crosssectional approach was used involving a total of 175 students in England from six different age groups (ranging from 4 year olds to 20 year olds). Students were presented, on separate occasions, with specimens of a brown rat, a starling and a herring and asked to draw what they thought was inside each specimen. On a final occasion, they were also asked to draw what they thought was inside themselves. Repeated inspections of the completed drawings allowed us to construct a seven point scale of 'skeletal understanding'. Our analysis shows the extent to which student understanding increases with age and the degree to which pupils know more about human than other skeletons. The findings are interpreted with reference to current trends in English science curricula and pedagogy. We comment in particular on the current inability of most students to see the skeleton as a functional, integrated whole.     

Cumulative proactive interference in animal memory

Events occurring on the prior trial in delayed matching-to-sample tasks can proactively interfere with accurate matching on the current trial. The present study investigated the accumulation of proactive interference in delayed matching-to-sample at the local level of two consecutive trials, as well as in terms of a general performance decrement accumulating over the session. Higher-order analyses, in terms of the parameters of negative exponential functions fitted to the data, showed that the magnitude of the local proactive-interference effect resulting from inter-trial disagreement of stimuli decreased over the session. Furthermore, there was no evidence for the general performance decrement over the session, which is frequently attributed to proactive interference. The attenuation of the local proactive-interference effect was accounted for in terms of changes in the relative probabilities of agreeing and nonagreeing trials.     

托起畜牧业发展的希望——访山东省畜牧兽医学校

山东省畜牧兽医学校是一所国家级重点中专校。在全国农字号中等职业学校呈滑坡趋势的形势下，该校２０００年招生竟达到１５００人，超额完成了招生计划。在当前，中等职业学校毕业生就业难，已成了一个不争的事实。但在该校每年自行举办的毕业生供需见面会上，来自省内外几十家企业、上百家单位的领导和代表按约定的时间云集牧校，形成了热闹非凡的人才市场；有的企业少则要五六人，多则要几十人，一个学生几家争的场面屡见不鲜；供需见面会每次被招聘的学生占应届毕业生的７０％～９０％。该校毕业生当年就业率一直保持在１００％。记者在…