Bioengineering English
某些催化RNA具备类似于性交换的功能。
Following the development of a lipid-protein surface layer and replicating RNA and DNA informational molecules, the events leading to the emergence of living cells would have included the origin of the genetic code; the sequestering of RNA or DNA into cell-like structures; and the development of metabolic pathways.
接下来脂蛋白表层的形成，RNA的复制,DNA信息分子的形成，最终导致活细胞的出现，包括最初的遗传密码，RNA或DNA被包裹进细胞样的结构中；及代谢途径的建立。 The Earliest Cells
The oldest fossils that may represent living cells are found in rocks that are about 3.5 billion years old. The cells were probably anaerobic heterotrophs, with autotrophs arising much later. The first autotrophs produced their own nutrients and released O,-a metabolic by-product that had a crucial impact on later life forms. The resulting ozone layer in the earth's atmosphere reduced the penetration of ultraviolet light. As a result, cells would survive in shallow water and on the land surface. The increasing quantity of atmospheric oxygen also permitted the evolution of aerobic cells and cellular respiration, which in turn signaled the beginning of the global carbon cycle.Although the earliest cells were all prokaryotes, by about 1.5 billion years ago eukaryotes appeared.
能说明活细胞存在的最古老化石大约有35亿年了。最早出现的细胞可能是厌氧异氧生物，自养生物很久后出现。最早的自养生物自己生产营养并释放氧气，这个新陈代谢副产品对后期生命的形成有一个深远的影响。臭氧层的出现减少了紫外线的渗透。结果，细胞就能够在浅水区和陆地上生存了。大气中氧气数量的增加使得需氧细胞进化并产生细胞呼吸，这预示着全球碳循环的开始。最早期的细胞都是原核生物，直到15亿年后，真核细胞才出现。 The Changing Face of planet Earth
Changes in land masses, the seas, and climate have greatly affected the evolution of life on the earth. The basic parts of the planet include a light, solid crust over a hot, semisolid mantle and an
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Bioengineering English
inner, partially molten core. Massive segments or plates of the crust move over the mantle in the process of continental drift. Over the past 500 million years, continental drift has sculpted the earth's crusts to produce the form and distribution of present-day continents. Climatic changes that greatly affected living organisms accompanied these plate movements; the period was marked by occasional waves of mass extinctions of living creatures. Organisms were also affected by periods of glaciation that followed variations in the earth's orbit and in the output of energy by the sun.
大陆板快，海洋的改变，以及气候对地球生命的进化都有深远影响。地幔上大板快地壳的挤压形成大陆漂移。大陆漂移雕塑了地壳的外观，使现在大陆形成。伴随板块运动，气候改变对活有机体有深远影响。在特定时期的生物大量灭亡高峰是这个时期的见证。生物也受冰河期影响，在冰河期，地球轨道和太阳能的输出都发生了很大变化。 Taxonomy: Categorizing the Variety of living Things
Biologists use the binomial system of nomenclature developed by Linnaeus to categorize the varieties of life on the earth. The system assigns each type of organism to a genus and species. Organisms are then further classified into higher taxonomic categories-family, order, class, division (plants), phylum (animals), and kingdom. Evidence from many subfields of biology, such as biochemistry and comparative anatomy, helps define species and higher taxa (taxon). And whereas species were originally defined in terms of morphological traits, today biologists generally use the criterion of a reproductively isolated population.
生物学家利用林奈发展的双名法对生物分类。系统选定每个类型的生物进入属和种，然后将生物进一步分类更高级类别中，即科，目，纲，门，界。来自于生物化学和比较解剖学等亚生物学领域的证据有助于划分物种和更高级的分类单位，然而物种最初依据形态学特征进行分类的，今天生物学家大体上使用孤立多产的群体作为标准。
Taxonomy reveals a great deal about the evolutionary relationships among organisms. A clade is a taxonomic unit whose members are derived from a common ancestor.
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Bioengineering English
分类学揭示了物种间进化的大量关系。进化枝中的成员来自一个共同的祖先。 The Five Kingdoms
A phylogenetic tree is a graphic representation of evolutionary relationships. Your text uses a common five-kingdom arrangement: organisms are grouped into the kingdoms Monera, Protista, Fungi, Plantae, and Animalia. Although this system is a convenient organizational tool, the kingdoms are probably no true clades.
进化系统树是进化关系的图解表现。教材中使用一个通用的5界：？，？，真菌，植物，动物。尽管这个系统是一个便利的组织工具，5界划分可能不是正确的进化枝。
Glossary
Big Bang 大爆炸
An explosion producing a pressure oscillation of the order of a millibar or more at a distant point on the Earth. e.g., the eruption of Krakatoa in 1883. Large nuclear fusion
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explosions are comparable. crust 地壳
The crust of the Earth is the outer shell of the Earth, defined by its composition and the properties of some seismic waves.
Bioengineering English
mantle 地幔
The part of the interior of the Earth between the crust and the core. core 核心
The core of the Earth is that part lying below the mantle.
coacervate 团聚体，凝聚层
A collection of organic macromolecules surrounded by water molecules that are aligned to fon-n a sphere. proteinoid 类蛋白[质]
A proteinlike structure of branched amino acid chains that is the basic structure of a microsphere.
continental drift 大陆漂移
The theory that the present continents result from the break-up of a larger continent and have moved independently to their present positions.
binomial system of nomenclature双名法 Uses two Latin names, genus and species, for each type of organism. genus 属
(plural, genera) A unit used in the
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liposome 脂质体
A vesicle formed by the homogenization (emulsification) of phospholipids in dilute salt solutions. Liposomes are the prototypes of membrane-bound biologic structures. ozone layer 臭氧层
A layer of the atmosphere, about 20 to 50 km above the surface, which contains ozone produced by ultraviolet radiation.
classification of plants and animals. A genus consists of a number of closely related species, and members of the same genus often have a number of obvious characteristics in common by which they can clearly be seen to be related. species 物种
A unit used in the classification of plants and animals. Ideally a species is defined as a group of organisms that interbreed with each other to produce fertile offspring. family 科
A unit used in the classification of plants and animals. A family consists of a number of closely related or similar genera or
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