揭示地球生命起源的岩石

在澳大利亚西部一处连绵10公里的狭长区域内，裸露着许多形状怪异、貌似岩石的土丘。这些土丘大小不一、形状各异，有的比人的指甲还要小，有的则比一个成人还要高，有的像装鸡蛋的纸盒，有的似海洋波浪。古怪土丘的学名为“叠层石”（stromatolite），距今大约有34亿年。     

“我国主要植物群落的分布图”立体彩色教具的制作

“我国主要植物群落的分布图”立体彩色教具的制作１制作１．１材料：木框、玻璃、塑料泡沫、薄硬纸片、纸浆板、４．ＳＶ电灯泡、闸合开关、细电线、电池、旧电筒、铜丝、螺钉、大头针、胶布、彩色吹塑纸、红漆、蓝漆、铁拉手等。１．２规格：长７４ｃｍ、宽５７ｃｍ、高...     

耳的结构教具的制作与使用

用有机玻璃封闭耳结构模型的外耳道、鼓室和咽鼓管,将麦克风植入内耳;锯下耳廓,在耳廓及对侧分别安装磁铁和铁片,便于相互间的分离与组合。麦克风与计算机相连,打开“声卡虚拟示波器”于示波器工作状态：观察由于音频和分贝变化．引发的波频与波幅的变化。用以说明耳的功能：将声波转变为以电流形式传导的神经冲动。在声音频率和分贝不变的情况下通过拆、装耳廓,观察示波器显示的波幅的变化,感受耳廓收集声波的功能。     

"生命起源"一节的教学设计

1．1知识目标 通过对生命起源的化学进化过程的学习．让学生了解地球上的原始生命是由非生命物质逐步演化而来的,理解生命与非生命物质的统一性,掌握生命起源的化学进化过程。     

“叶芽发育成枝条”活动模型的制作与使用

1目的用活动模型把叶芽发育成技条的动态变化过程表现出来,突破教学难点,便于学生理解、掌握,达到形象直观的教学目的。2制作方法①取6块长27cm×宽19～7．5cm的白板纸卷成简状,用宽3cm的牛皮纸条内外两面粘合接口,制成直径分别为5．5cm、49cm、43cm、3．7cm、3．1cm和2．5cm的6个纸简,作为茎段。如图1。②取6块长10cm×宽7cm的白板纸,按图2所示窝成锥形,并用针书针钉住。将下端剪圆,缝在茎段的一端,作为侧芽。如图人③取长29～38cm的塑料打包带6根,紧靠侧芽缝在茎段上,作叶柄。如图3左。用绿色标语纸接由小到大剪制6对叶片。每…     

生命起源的现代探讨──基于磷酰化氨基酸的核酸和蛋白质共起源学说评述

先有核酸还是先有蛋白质,是当前生命起源研究中的难题。本文在讨论现代生物学和物理学对生命本质的认识后,评介了中国学者提出的一个基于N－磷酰化氨基酸自组装的蛋白质和核酸共进化的模型。在有核畜存在时;磷酸化氨基酸自组装提供了一个能把蛋白质合成和核酸合成偶联起来的最小的分子模型。同其他生命起源学说相比,这一模型更符合生命的基本特征（自复制、生长、变异和进化）,以及Eigen“超循环论”的自组织和进化的理论框架。     

“探究蚯蚓运动速率”实验装置的设计制作

介绍了“探究蚯蚓运动速率”实验装置的设计、制作及使用步骤。     

进化与适应观培养的单元教学设计——以“生命起源和生物进化”为例

以“生命起源和生物进化”为例,阐述了进化与适应观培养的单元教学设计。通过纵向上注重任务解构—活动设计—概念建构一致性,横向上注重任务间环环相扣和素养发展层层递进,构建了网络型单元教学体系,进而聚焦系统知识和素养培育,提升学科育人价值。教学实践表明,在单元教学设计中注重提升教学设计站位,从学科育人的视角创设情境,通过一体化的单元教学设计网络实现核心素养落地,具有很好的教学效果。     

对“果酒和果醋的制作”实验的改进

按照课程标准的要求．组织学生实施了人教版普通高中课程标准实验教科书生物选修1专题1课题1实验“果酒和果醋的制作”,实验过程中,对如何搞好该实验进行了探究和改进．取得良好的效果。     

合理使用教具打造高职院校“以学生为中心”的高效课堂

"以学生为中心"强调采用协作式、个别化、小组讨论等教学形式或采用多种教学形式组合起来进行教学,要求重视和体现学生的主体作用,突出教师的主导作用。本文主要介绍了高职院校的教师如能将有趣、直观的教具纳入教学过程,选择并适时使用教具,将对激发学生学习兴趣,突出教学重点,突破教学难点,优化课堂教学结构,发展学生创新思维能力以及提高教学质量和效率起到至关重要的作用。     

Thoughts on the origin and nature of life and intelligence on earth

Believing, for good reasons, that our Universe engenders the occurrence of Life, it is probable that Life appeared more than once on young planet Earth. The universality of our genetic code indicates though, that only one line produced a population that was cellular, autopoietic, responsive intelligently (i.e., to its advantage) to its environment, and capable of reproduction. Its evolution took time during which other intermediate or incipient forms of life disappeared. Trying to retrace ab initio the preceding chemical evolution on our young planet, we may not repeat the chemistry which led to our line. One can argue that it may be profitable to attempt to construct artificial life forms using the kind of building blocks that we learned to know through studying the chemistry of our life. Independently, computers are being built, or are planned, which possess memory that can be used appropriately (intelligently), and which to some extent can repair and reproduce themselves. Such Life does not depend on our biochemistry. However, these machines do perform as yet only partly along the lines of our human intelligence which is guided by self-awareness and a sense of individual integrity, and are thereby not equipped to search for Understanding and Self-expression.     

A proposal concerning the origin of life on the planet earth

Summary The widely accepted Oparin thesis for the origin and early evolution of life seems sufficiently far from the true state of affairs as to be considered incorrect. It is proposed that life on earth actually arose in the planet's atmosphere, however an atmosphere very different from the present one. Because of an extremely warm surface, the early earth may have possessed no liquid surface water, its water being partitioned between a molten crust and a fairly dense atmosphere. Early preliving systems are taken to arise in the droplet phase in such an atmosphere. The early earth, which resembled Venus then and to some extent now, underwent a transition to its present condition largely as a result of the evolution of methanogenic metabolism.     

The origin of optical asymmetry on earth.

The nature of optical isomerism, and the problem of the origin of optical asymmetry in relation to the origin of life are defined. Developments in particle physics, such as the discovery of parity non-conservation in weak interactions and more recently, of neutral currents, are described. Their significance is that there are a number of possible mechanisms whereby the fundamental asymmetry of matter could be reflected in a preference for one enantiomer over the other, and that, contrary to long-established views, optical isomers do not have identical energy contents: the difference, however, is estimated to be very small. Theories regarding the origin of optical asymmetry are classified in a two-dimensional matrix (origin by chance or due to already existing order; susceptible or not susceptible to experimental test). Recent experimental results and theoretical speculations are reviewed, and proposals are made for further experimental work.     

The origin of life on Earth

Terrestrial life can be schematically described as organic molecules organized in liquid water. According to Oparin's hypothesis, organic building blocks required for early life were produced from simple organic molecules formed in a primitive reducing atmosphere. Precursors of lipids, nucleic acids and enzymes obtained in the laboratory under simulating conditions are reviewed. Geochemists favor now a less reducing atmosphere dominated by carbon dioxide. In such an atmosphere, very few building blocks are formed under prebiotic conditions. Import of extraterrestrial organic molecules may represent an alternative supply. Experimental support for such an alternative scenario is examined in comets, cosmic dust, meteorites and micrometeorites. Even the prebiotic broth receives today severe criticism for being implausible. In contrast to the classical scenario, a chemoautotrophic origin of life is discussed. Finally, interesting information related to early terrestrial life may be gained from Mars exploration.     

The origin of homeostasis in the early earth

Summary An equation is developed that describes the condition of homeostasis in a general molecular system containing catalysts. In a prebiotic environment, this condition first results from a critical level of catalytic feedback in feedback loops containing differing organic molecular species. This critical level results in temporary exponential growth in concentrations of those catalyst species participating in the feedback loops, leading to homeostasis as the steady-state endpoint. None of the molecules in any feedback loop need be self-replicating for this autocatalysis to occur. Homeostasis is regarded as a definition of life at the lowest possible hierarchical level. A general mathematical boundary condition is derived for the critical level of catalytic feedback mentioned above-in effect, an origin of life condition. The paper argues that any natural prebiotic system of organic molecules in an H₂O medium will automatically form many catalytic feedback loops, even if of very low catalytic efficiency. The analysis in this paper indicates that high temperatures strongly increase the efficiency of such catalytic feedback. If the temperature and total concentration of carbon in the system (e.g., in CO₂, CH₄, etc.) are sufficiently high, the critical condition for initial exponential growth will be attained. High initial temperatures for the earth are predicted by the planetesimal accretion model.     

The ribotype theory on the origin of life

The ribotype is defined as the ribonucleoprotein system of any cell. The theory substitutes the genotype-phenotype duality with the trinity genotype-ribotype-phenotype, and proposes that life on earth originated with the ancestors of today's ribotypes.The first three chapters describe separate models on precellular evolution, the evolution of protocells and the nature of the cell respectively, and the unity of the theory comes from the fact that they form a consistent and interdependent whole.The core of the theory is the ribotype hypothesis, of which two formulations are given. The restricted version is based on a link between ribotypes and ribosome biogenesis, and provides an explanation for the difference between 70S and 80S ribosomes. The general version describes a link between ribotypes and cell-types and explains why prokaryotes have 70S ribosomes, eukaryotes 80S ribosomes and endosymbionts a type of ribosomes similar to the bacterial ones.If the creation hypothesis, panspermia and spontaneous generation are set aside, all alternative models of the origin of life belong to two schemes which are referred to as the genotype and the phenotype theories. It is shown that these theories rely on some discontinuity between past and present biological principles because of the need to break their inherent chicken-and-egg paradoxes, while the ribotype theory does not. Its hypotheses, free and arbitrary as they are or appear to be, have been built exclusively on properties and processes for which solid evidence exists, and the continuity between past and present biological laws is assumed as a corollary. Finally, it is shown that falsification tests are possible, and some of them are expected in the relatively near future.