2005Consistency of patterns between in otolith chemistry an example andsalinity reconstructions

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R.K. Workman, S.R. Hart / Earth and Planetary Science Letters 231 (2005) 53–72
assumptions about melt generation, melt transport, and differentiation processes that have affected these upper mantle melts. Unfortunately, it is just these processes that we are trying to understand, rather than assume a priori. The most compelling evidence for upper mantle depletion comes from the heavy-element isotopic composition of MORBs. Although MORBs and their residues, abyssal peridotites, have some degree of heterogeneity in radiogenic isotope ratios (Sr–Nd–Pb– Hf), they are focused within a small range of values relative to ocean island basalts and are, with very few exceptions, depleted from bulk earth values in 87Sr/86Sr, 143 Nd/144Nd, and 176Hf/177Hf, thus requiring a longterm history of low Rb/Sr, Hf/Lu, and Nd/Sm (i.e. incompatible element depletion). Direct evidence for upper mantle depletion came with the classic trace element studies of Johnson et al. [10] and Johnson and Dick [11] on abyssal peridotites, but most of the observed depletion in these peridotites is due to melt extraction during the latest spreading events, so that the composition of the general ambient upper mantle has been severely overprinted by this latest melting episode. Ultimately, we know that this mantle, which has been estimated to comprise 30–70% by mass of the bulk silicate earth, has been depleted over time in the highly incompatible (lithophile) elements ([1,8], refs. therein). Most models ascribe the depletion of the upper mantle to the extraction of the enriched continental crust, a process that has removed up to 90% of the most incompatible elements, and 80–85% of the heat-producing elements (e.g. [8]). Some part of the depletion may also be created by the preservation of recycled oceanic crust that is currently sequestered in unknown regions of the mantle. It is possible the lower mantle (below 670 km) has also been depleted by such processes, but this question is highly controversial at present. In place of assuming a set of bulk partition coefficients or a degree of melt extraction, we use in this paper the following constraints in deriving an average trace element composition of DMM: (1) trace element content of clinopyroxenes from abyssal peridotites, (2) isotopic evolution from primitive upper mantle (PUM), and (3) canonical trace element ratios in MORBs. Abyssal peridotite data from the literature, the backbone of this study, are treated in a way reminiscent of studies such as Loubet et al. [12], Hart and Zindler [13], and McDonough and Sun [14]. Abyssal perido-

揭秘托福阅读的大坑货：地质时期为了帮助大家做好地质时期这种题材的托福阅读，下面小编给大家带来揭秘托福阅读的大坑货：地质时期，希望看了这篇文章后，大家会有所收获！揭秘托福阅读的大坑货：地质时期TPO 里面有一篇阅读文章的开头是这么写的：Paleozoic Era 334 to 248 million years agoMesozoic Era 245 to 65 million years ago—Triassic Period—Jurassic Period—Cretaceous PeriodCenozoic Era 65 million years ago to the present想必大家第一反应是崩溃的，这都是什么鬼?What the heck?一个不幸的消息是出现这些词的托福文章还不少。

虽然托福是考查大家的英语语言能力水平，但是了解托福常考学科的背景知识，可以帮助大家更快地熟悉阅读乃至听力里面的内容。

今天V酱请来了朗播网的王宜涵老师，带大家了解一下这些单词背后到底指的什么和它们背后的故事前面超复杂的英文翻译其实是这样的：古生代(从 3 亿 3 千 4 百万年前到 2 亿 4 千 8 百万年前)中生代(从 2 亿 4 千 5 百万年前到 6 千 5 百万年前)—三叠纪时期—侏罗纪时期—白垩纪时期新生代 (从 6 千 5 百万年前到现在)在地质学和考古学中，地质年代是用来描述地球历史事件的时间单位。

其中最大的时间单位是宙/元(eon)，宙下是代(era)，代下分纪(period)，纪下分世(epoch)，世下分期(age)。

如下图所示。

一 | Paleozoic Era 古生代古生代意为远古的生物时代，持续约3 亿年。

对动物界来说，这是一个重要时期。

它以一场至今不能完全解释清楚的进化拉开了寒武纪的序幕。

寒武纪动物的活动范围只限于海洋，但在古生代的廷续下，有些动物的活动转向干燥的陆地。

古生代后期，爬行动物和类似哺乳动物的动物出现，古生代以迄今所知最大的一次生物绝灭宣吿完结。

第27卷　第2期2002年4月动物分类学报AC TA ZOO TAXONOMICA SIN ICA Vol.27,No.2Ap r .,20023中国科学院现代古生物学和地层学开放研究实验室(编号013103),地质行业发展基金(H Y 979801)、国土资源部百名跨世纪科技人才培养计划(编号9801)、国家杰出青年科学基金(编号30025006)共同资助项目.收稿日期:2001Ο11Ο05,修订日期:2001Ο12Ο02.274内蒙古自治区中侏罗世表翼蛉化石一新种3(脉翅目:翼蛉科)任　东(首都师范大学生物系　北京100037,中国科学院南京地质古生物研究所现代古生物学及地层学开放研究实验室　南京　210008,E 2mail :rendongprof @ )尹继才(中国地质博物馆　北京　100034)摘要　描述表翼蛉属化石1新种,潘氏表翼蛉Epiosmyl us panf ilovi sp.nov.,讨论了表翼蛉属的科级分类问题。

标本采自内蒙古自治区宁城县山头乡中侏罗世地层中。

关键词　脉翅目,翼蛉科,表翼蛉属,新种,中侏罗世.中图分类号　Q 961,Q 969.383.8Panfilov (1980)根据采自哈萨克斯坦晚侏罗世地层中的化石建立一个脉翅目新科———表翼蛉科Epiosmylidae ,但由于化石标本不好,尤其是翅脉特征尚存有疑问,因此其科级地位一直存在争论。

Lambkin (1988)认为Epiosmyl us longicor nis 的Sc +R 1脉在翅尖端汇合、CuP 具有较宽的栉状支脉等特征,无疑应归入翼蛉科。

Makarkin (1990)也认为Epiosmyl us 应归于翼蛉科。

但由于Epiosmyl us 迄今尚未有保存完好的、具有清晰翅脉的化石材料,所以其真正的科级分类位置还不能十分肯定。

近年来笔者在我国东北中生代地层中采集了大量的昆虫化石标本(任东,卢立伍等,1995,1996;Ren ,1996,2002),在整理采自内蒙古自治区宁城中侏罗世化石标本时,又发现了第2件表翼蛉化石,该化石保存有翅脉特征,虫体其它特征未被保存,由于翅脉十分清晰,因此这件化石十分珍贵。

第一章绪论一、名词1、毒理学: 研究所有外源因素对生物系统的损害作用、生物学机制、安全性评价与危险性分析的科学。

2、毒物: 是指较低的剂量进入机体后能引起疾病或危及生命的物质。

二、选择1、描述毒理学直接关注的是——，以期为安全性评价和危险度管理提供信息。

AA、毒性鉴定B、接触毒物时间C、接触毒物剂量D、毒性强弱E、以上全是2、经典的毒理学研究对象是A、核素B、细菌C、病毒D、各种化学物质E、以上都是3、外源化学物的概念A、存在于人类生活和外界环境中B、与人类接触并进入机体C、具有生物活性，并有损害作用D、并非人体成分和营养物质E、以上都是三、填空1、毒理学研究领域主要分为描述毒理学、机制毒理学和管理毒理学2、动物实验的“3R”法分别是优化、减少和取代第二章毒理学基本概念一、名词1、外源化学物：是在人类生活的外界环境中存在、可能与机体接触并进入机体，在体内呈现一定的生物学作用的化学物质，又称为“外源生物活性物质”。

2、毒性：是指化学物引起有害作用的固有的能力。

3、毒物：在一定的条件下，以较小剂量进入机体就能干扰正常的生化过程或生理功能，引起暂时或永久性的病理改变、甚至危及生命的化学物质。

4、靶器官：毒物被吸收后随血流到全身各组织器官，但起发挥毒作用的部位则只限于一个或几个组织器官，毒物直接发挥作用的器官称为靶器官。

5、生物学标志：是指外源化学物通过生物学屏障进入组织或体液后，对该化学物或其代谢产物、以及它们所引起的生物学效应的测定指标。

6、暴露生物学标志：是测定组织、体液或排泄物中的外源化学物、其代谢物或与内源性物质的反应产物，作为吸收剂量或靶剂量的指标，可提供有关化学物质暴露的信息。

7、效应生物学标志：指机体中可测出的生化、生理、行为或其他改变的指标。

8、易感生物学标志：是关于个体对外源化学物的生物易感性的指标，反映机体先天具有或后天获得的对暴露外源性物质产生反应能力的指标。

9、量反应：此类效应的观察结果为计量资料，有强度和性质的差别，可用某种测量的数值表示。

The author discovered one new feature after another 71~85 when he began to work in earnest and saw how just the Professor's criticism had been. By the end of the third day, the author had learned 86~104 the best entomological lesson in his life, one that was to guide his subsequent study and research. The eight months Scudder spent studying 105~122 haemulons was of greater value to him than years of later investigation into insects.
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Born in Boston, he was graduated from Williams College and got his B.A. (1857) and then he got his B.S. at Harvard (1862). As the founder of American insect paleontology ( 古 生 物 学 ) and an authority on Orthoptera (直翅目) and Lepidoptera (鳞翅目), he was assistant to Louis Agassiz (1862~1864), custodian of the Boston Society of Natural History (1864~1870), assistant librarian of Harvard (1879~1882), and paleontologist of the U.S. Geological Survey (1886~1892). His works include A Century of Orthoptera (1879), Butterflies: Their Structure, Changes, and Life-Histories (1881), and Fossil Insects of North America (1890).

超高压变质带中的变质不均一性姜为佳;刘贻灿【摘要】不同造山带的榴辉岩和有关变质表壳岩石中柯石英及金刚石等标志性超高压变质矿物的发现，已证明陆壳岩石能俯冲到大于120 km 的地幔深度并折返至地表。

超高压变质带中榴辉岩和相关的榴辉岩相岩石常常与具有低级变质矿物组合的岩石(如变质花岗岩、花岗片麻岩、变玄武岩或斜长角闪岩等)密切伴生，然而它们之间的相互关系和成因联系却一直是地质学家长期争议的焦点。

查明这两类岩石的变质演化历史以及相互联系，对理解大陆的深俯冲及折返过程具有重要意义。

在总结、分析若干陆陆碰撞造山带中变质不均一性的研究成果及成因解释的基础上，讨论了影响岩石保存超高压变质记录的若干关键因素，包括原岩性质、变质流体、构造变形、退变质作用等。

%Ultrahigh-pressure (UHP)index minerals,such as coesite and diamond in eclogites and related metamorphosed supracrustal rocks from various orogenic belts,suggest that continental crustal rockscan be subducted to mantle depths of more than 120 km and subsequently return to the surface.Furthermore,eclogites and related eclogite-facies rocks,and low-grade mineral assemblage-bearing rocks (i.e. metagranite, granitic gneiss, meta-basalt and amphibolite ) commonly coexist in UHP metamorphic belts.However,their relationship and petrogenetic links between high-grade and lower grade assemblage-bearing rocks are often matter of debate.Hence, to clarify the metamorphic evolutionary histories and the correlation of the two groupsof rocks plays a significant role in understanding the continental deep subduciton and exhumation processes. Some investigations on themetamorphic heterogeneity within a single UHP metamorphic belt were summarized.On this basis,several key factors such as protolith nature, metamorphic fluids,structural deformation and retrogression,which affect the preservation of UHP metamorphic records,were discussed.【期刊名称】《地球科学与环境学报》【年(卷),期】2016(038)002【总页数】12页(P160-171)【关键词】超高压变质带;变质不均一性;大陆深俯冲;折返;碰撞造山带;榴辉岩;退变质作用【作者】姜为佳;刘贻灿【作者单位】中国科学院壳幔物质与环境重点实验室，安徽合肥 230026; 中国科学技术大学地球和空间科学学院，安徽合肥 230026;中国科学院壳幔物质与环境重点实验室，安徽合肥 230026; 中国科学技术大学地球和空间科学学院，安徽合肥 230026【正文语种】中文【中图分类】P588.3板块构造理论自20世纪60年代以来已被地球科学研究领域所熟识，并成为认识岩石圈结构、组成及演化的基本理论。

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对 沉积物 的形 成环 境Байду номын сангаас演化 具 有 良好 的 指 示 意义 （ 金
１ ）中 国科 学 院海洋 研究所 海 洋地质 与环 境重 点实 验室 ， 山东青 岛 ，６ ０ １ ２６ ７ ； ２ ）中 国石 油大 学 （ 东 ） 华 地球科 学 与技术 学 院 ， 山东青 岛 ，６ ５ ５ ２ ６５ ；
３ ）山东省 油藏 地质 重点 实验 室 ， 山东东 营 ，５ ０ １ ２ ７ ６
关键词 ： 度 ； 形 ； 海 ； 粒 分 东 内陆 架 ； Ｃ ０ ５孔 Ｅ ２０
沉 积 物粒 度 是衡 量 沉 积介 质 能 量 的一 种 参数 ， 其 分布特 征 与沉积 时 的动 力 环境 密 切 相 关 ， 作 为 常 判 断陆源 沉积 岩成 因及沉 积 环境 的指标 （ 温小 浩 等 ， ２ ０ ； 方 建 等 ， ０ ９ 。 自 ２ 世 纪 ６ 年 代 ０５ 徐 ２０ ） ０ Ｏ Ｍａ ｄ ｌｒ ｔ １ ６ ） 出分形 理论 ， 来 研究 自然 界 ｎ ｅ ｏ （９ ７提 ｂ 用 中没有 特征 长度但 有 自相 似 性 的 图形 与 现 象 ， 多 众 学 者将 该 理 论 在 不 同领 域 进 行 了广 泛 的研 究 。 目 前， 虽然 分形 自身 还存 在着很 大缺 陷 ， 至还 没有 严 甚

目　录2015年武汉大学887普通生物学（D卷）考研真题2013年武汉大学889普通生物学（A卷）考研真题2007年武汉大学638普通生物学考研真题2006年武汉大学369普通生物学考研真题2005年武汉大学357普通生物学考研真题2004年武汉大学826普通生物学考研真题2004年武汉大学375普通生物学考研真题2002年武汉大学626普通生物学考研真题2015年武汉大学887普通生物学（D卷）考研真题武汉大学2015年攻读硕士学位研究生入学考试试题（满分值150分）科目名称：普通生物学卷）科目代码：887注意；所有答题内容必须写在答题纸上，凡写在试题或草稿纸上的一律无效,一、名词解释（共10小题，每小题4分，共40分）】、Transcription2、Heterotrophic organism3、Meiosis4、Cell respiration5*Semiconsfinative replication6、Gene therapy7、Exon8、Pollination9、Douhie circulation10、Passive transport二、简答题（共6小题，每小题10分，共60分）1、简述种子的基本结构及各部分的作用.2、树皮环剥后.为什么树常会死亡？有的树干中空，为什么树仍能继续存活？3、细胞周期分为哪几个时期？各个时期的特点如何？4、简述有丝分裂和减数分裂的意义.5、简述生物遗传变异的主要来源。

共2页第1页6、筒述双受精的具体过程.三、论述题（共2小题，毒小题25分，共5。

分）L从子叶数目、根系、茎内雄管束、叶脉、花各部分数目等五个方面说'明双子叶植物和单子叶植物的不同。

2、生命科学研究最终目的是为了造福人类.从应用前景来看，你认为生命科学哪一方向的研究最为重要？共2页第2页2013年武汉大学889普通生物学（入卷）考研真题武汉大学2013年攻读硕士学位研究生入学考试试题（满分位150分）..主旦名名匚普通生物学3A）科目代码七町注意：所有答魏内容必顼写在答我圾上・凡写在试it或者蕈横纸上的一律无效.—、名词解释（共6小题.每小SS5分，共30分）1、双重呼吸2、光周期现象，3、氧化磷酸化'4、同功器官5、半保留复制6、噬菌体*二、填空题（共1。

The Yangtze Alligator,scientifically known as Alligator sinensis,is a unique species of crocodile native to China.It is often referred to as the living fossil due to its ancient lineage,which dates back to the Mesozoic era,making it one of the smallest crocodile species in the world.Habitat and Distribution:The Yangtze Alligator primarily inhabits the freshwater regions of the Yangtze River basin in China.Historically,their range extended throughout the river system,but due to habitat loss and human activities,their distribution has been significantly reduced.Today, they are mainly found in the provinces of Anhui and Jiangsu.Physical Characteristics:These alligators are characterized by their dark,almost black skin,which provides excellent camouflage in their natural habitat.They have a robust body with a long, muscular tail that is used for swimming and balance.The Yangtze Alligator has a distinct snout,which is shorter and rounder compared to other crocodile species.They also possess powerful jaws equipped with sharp teeth,which are essential for their carnivorous diet.Diet and Hunting Behavior:As apex predators,Yangtze Alligators primarily feed on fish,amphibians,and small mammals.They are ambush hunters,often lying in wait near the waters edge or submerged in the water,using their camouflage to remain undetected until their prey comes within striking distance.Once the prey is within reach,they use their powerful jaws to seize it and drag it underwater to drown.Reproduction and Life Cycle:The Yangtze Alligator is oviparous,meaning they lay eggs.The breeding season typically occurs in June,with the female laying between20to50eggs in a nest she digs in the sand.The eggs are then guarded by the female until they hatch,which can take up to two months.The hatchlings are independent from birth and must fend for themselves immediately.Conservation Status:Due to the loss of habitat,poaching for their skin and meat,and the collection of eggs for consumption,the Yangtze Alligator is critically endangered.Efforts have been made to conserve this species,including the establishment of nature reserves and captive breeding programs.These initiatives aim to increase their population and reintroduce them into the wild.Cultural Significance:In Chinese culture,the Yangtze Alligator has been revered for its longevity and is often associated with wisdom and strength.It is also a symbol of good luck and is featured in various folktales and legends.In conclusion,the Yangtze Alligator is a fascinating and ancient creature that plays a crucial role in the ecosystem of the Yangtze River.Its conservation is vital not only for the species itself but also for the health of the river and the biodiversity it supports.It is our responsibility to protect and preserve this remarkable animal for future generations to appreciate and learn from.。

托福考试 复习TPO 31—1 Speciation in Geographically Isolated Populations原文：【1】Evolutionary biologists believe that speciation, the formation of a new species, often begins when some kind of physical barrier arises and divides a population of a single species into separate subpopulations. Physical separation between subpopulations promotes the formation of new species because once the members of one subpopulation can no longer mate with members of another subpopulation, they cannot exchange variant genes that arise in one of the subpopulations. In the absences of gene flow between the subpopulations, genetic differences between the groups begin to accumulate. Eventually the subpopulations become so genetically distinct that they cannot interbreed even if the physical barriers between them were removed. At this point the subpopulations have evolved into distinct species. This route to speciation is known as allopatry (“alio-”means “different”，and “patria”means “homeland”).【2】Allopatric speciation may be the main speciation route. This should not be surprising, since allopatry is pretty common. In general, the subpopulations of most species are separated from each other by some measurable distance. So even under normal situations the gene flow among the subpopulations is more of an intermittent trickle than a steady stream. In addition, barriers can rapidly arise and shut off the trickle. For example, in the 1800s a monstrous earthquake changed the course of the Mississippi River, a large river flowing in the central part of the United States of America. The change separated populations of insects now living alongopposite shore, completely cutting off gene flow between them.【3】Geographic isolation also can proceed slowly, over great spans of time. We find evidence of such extended events in the fossil record, which affords glimpses into the breakup of formerly continuous environments. For example, during past ice ages, glaciers advanced down through North America and Europe and gradually cut off parts of populations from one another. When the glacier retreated, the separated populations of plants and animals came into contact again. Some groups that had descended from the same parent population were no longer reproductively compatible—they had evolved into separate species. In other groups, however, genetic divergences had not proceeded so far, and the descendants could still interbreed—for them, reproductive isolation was not completed, and so speciation had not occurred.【4】Allopatric speciation can also be brought by the imperceptibly slow but colossal movements of the tectonic plates that make up Earth’s surface. About 5 million years ago such geologic movements created the land bridge between North America and South America that we call the Isthmus of Panama. The formation of the isthmus had important consequences for global patterns of ocean water flow. While previously the gap between the continents had allowed a free flow of water, now the isthmus presented a barrier that divided the Atlantic Ocean from the Pacific Ocean. This division set the stage for allopatric speciation among populations of fishes and other marine species.【5】In the 1980s, John Graves studied two populations of closely related fishes, onepopulation from the Atlantic side of isthmus, the other from the Pacific side. He compared four enzymes found in the muscles of each population. Graves found that all four Pacific enzymes function better at lower temperatures than the four Atlantic versions of the same enzymes. This is significant because Pacific seawater is typically 2 to 3 degrees cooler than seawater on the Atlantic side of isthmus. Analysis by gel electrophoresis revealed slight differences in amino acid sequence of the enzymes of two of the four pairs. This is significant because the amino acid sequence of an enzyme is determined by genes.【6】Graves drew two conclusions from these observations. First, at least some of the observed differences between the enzymes of the Atlantic and Pacific fish populations were not random but were the result of evolutionary adaption. Second, it appears that closely related populations of fishes on both sides of the isthmus are starting to genetically diverge from ea ch other. Because Graves’s study of geographically isolated populations of isthmus fishes offers a glimpse of the beginning of a process of gradual accumulation of mutations that are neutral or adaptive, divergences here might be evidence of allopatric speciation in process.题目：1.The word "promotes" in the passage is closest in meaning toA.describes.B.encourages.C.delays.D.requires.2.According to paragraph 1, allopatric speciation involves which of the following?A.The division of a population into subspecies.B.The reuniting of separated populations after they have become distinct species.C.The movement of a population to a new homeland.D.The absence of gene flow between subpopulations.3.Why does the author provide the information that "the subpopulations of most species are separated from each other by some measurable distance"?A.T o indicate how scientists are able to determine whether subpopulations of a species are allopatric.B.To define what it means for a group of animals or plants to be a subpopulation.C.To suggest that allopatric speciation is not the only route to subpopulation.D.T o help explain why allopatric speciation is a common way for new species to come about.4.The word "accumulate" in the passage is closest in meaning toA.Become more significant.B.Occur randomly.C.Gradually increase in number.D.Cause changes.5.In paragraph 2,why does the author mention that some insect populations were separated from each other by a change in the course of Mississippi River caused by an earthquake?A.T o make the point that some kind of physical barrier separates the subpopulations of most species.B.To support the claim that the condition of allopatry can sometimes arise in a short time.C.To provide an example of a situation in which gene flow among the subpopulations of a species happens at a slow rate.D.T o explain why insects living along opposite shores of the Mississippi River are very different from each other.6.According to paragraph 3，separation of subpopulations by glaciers resulted in speciation in those groups of plants and animals thatA.were reproductively isolated even after the glaciers disappeared.B.had adjusted to the old conditions caused by the glaciers.C.were able to survive being separated from their parent population.D.had experienced some genetic divergences from their parent population.7.The word "colossal" in the passage is closet in meaning toA.consistent.B.gradual.C.enormous.D.effective.8.According to paragraph 4, which of the following is true of the geologic movements that brought about the Isthmus of Panama?A.The movements brought populations of certain fishes and marine organisms intocontact with one another for the first time.B.The movements transferred populations of fishes and other marine animals between the Pacific and Atlantic Oceans.C.The movements created conditions that allowed water to flow more freely between the Pacific and Atlantic Oceans.D.The movements created conditions for the formation of new species of fishes and other marine animals.9.The word "sequence" in the passage is closet in meaning toA.quality.B.order.C.function.D.number.10.According to paragraph 5, by comparing the enzymes from two related groups of fishes on opposite sides of the isthmus, Graves found evidence thatA.there were slight genetic divergences between the two groups.B.the Atlantic group of fishes were descended from the Pacific group of fishes.C.the temperature of water on either side of the isthmus had changed.D.genetic changes in the Atlantic group of fishes were more rapid and frequent than in the Pacific group of fishes.11.It can be inferred from paragraph 5 and 6 that the reason Graves concluded that some of the differences between the Pacific and Atlantic enzymes were not random was thatA.each of the Pacific enzymes works better in cooler waters.B.the Enzymes of the Atlantic fish populations had not changed since the formation of the Isthmus of Panama.C.gel electrophoresis showed that the changes benefited both the Atlantic and the Pacific fish populations.D.the differences between the enzymes disappeared when the two fish populations were experimentally switched to other side of the isthmus.12.Which of the sentence below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.A.Graves's study provides evidence that isthmus fishes are in the process of becoming geographically isolated.B.Graves's study of mutating isthmus fishes yields results that differ from results of other studies involving allopatric speciation.C.Graves's study of isolated populations of isthmus fishes provides some evidence that allopatric speciation might be beginningD.Grave's study indicates that when isolated, populations of isthmus fished register neutral or adaptive mutations.13. Look at the four squares [■] that indicate where the following sentence can be added to the passage.Where would the sentence best fit? The formation of the isthmus had important consequences for global patterns of ocean water flow. Allopatric speciation can also be brought by the imperceptibly slow but colossalmovements of the tectonic plates that make up Earth's surface. ■【A】About 5 million years ago such geologic movements created the land bridge between North America and South America that we call the Isthmus of Panama. The formation of the isthmus had important consequences for global patterns of ocean water flow. ■【B】While previously the gap between the continents had allowed a free flow of water, now the isthmus presented a barrier that divided the Atlantic Ocean from the Pacific Ocean. ■【C】This division set the stage for allopatric speciation among populations of fishes and other marine species. ■【D】14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passages or are minor ideas in the passage. This question is worth 2 points.Allopatric speciation takes place when physically separated populations of a single species gradually diverge genetically to the point of becoming unable to interbreed A.Allopatric speciation is common because the gene flow between subpopulations is generally limited and the barriers that completely separate subpopulations can arise in a variety of ways.B.During past ice ages, some, but not all, subpopulations separated by glaciers evolved into distinct species.C.Speciation does not need to take place through allopatry because subpopulations will form distinct species whenever there are adaptive advantages or notD.Physical barriers from glaciers and the movement of tectonic plates form so slowly that the subpopulations on either side of the barriers usually do not form distinct species.E.Graves's study of fish populations separated by the Isthmus of Panama may well provide a picture of the beginning stages of speciation.F.Graves's study of physically separated fish populations show that there must be large differences between the environments of the isolated populations if allopatric speciation is to take place.答案：1.promote本身是促进的意思。

fossilization 例子
摘要：
1.化石的形成过程
2.化石的分类
3.化石的重要性
4.化石的例子
5.化石的保存与研究
正文：
化石是指在地层中保存下来的古生物的遗体、遗物或遗迹。

它们通过漫长的地质过程，被自然界的力量作用，逐渐形成并保存下来。

在科学家的研究中，化石是了解古生物、研究生物进化以及揭示地球历史的重要证据。

化石可以分为遗体化石、遗物化石和遗迹化石。

遗体化石是指古生物的完整或部分遗体，如骨骼、肌肉等。

遗物化石是指古生物的遗物，如卵、粪便等。

遗迹化石是指古生物活动留下的痕迹，如脚印、爬行痕迹等。

化石的重要性体现在它为科学家提供了研究生物进化的直接证据。

通过化石的研究，科学家可以了解古生物的结构、生活习性，甚至可以推测出古生物的生存环境。

同时，化石的研究也为科学家揭示地球历史提供了宝贵的信息。

在我国，化石的研究已经取得了举世瞩目的成果。

其中，最著名的化石例子有“北京人”头盖骨化石、恐龙化石、古鸟化石等。

这些化石的发现，不仅为科学家提供了重要的研究资料，同时也引起了全社会对古生物学和地球历史的关注。

为了保护和研究化石，我国政府和科学家们付出了巨大的努力。

一方面，政府出台了一系列政策，保护和监管化石资源。

另一方面，科学家们通过各种手段，对化石进行详细的研究和分析，以期获得更多有关古生物和地球历史的信息。

总之，化石是研究生物进化和地球历史的重要证据。

它们为我们揭示了古生物的奥秘，帮助我们更好地了解地球的过去。

南方农业学报　Journal of Southern Agriculture　2023，54（9）：2604-2613ISSN 2095-1191； CODEN NNXAABDOI：10.3969/j.issn.2095-1191.2023.09.011方格星虫线粒体全基因组密码子偏好性分析韩春丽，杨果豪，李天香，王健宇，熊忠萍，许尤厚，朱鹏，杨家林*，王鹏良*（北部湾大学海洋学院，广西钦州535011）摘要：【目的】探讨方格星虫线粒体基因组密码子偏好性，明确自然选择和基因突变对其密码子偏好性的作用，并充分利用密码子偏好性的特点，为方格星虫分子遗传改良提供科学依据。

【方法】根据方格星虫线粒体基因组序列，选取长度大于300 bp且以ATG开头的10个非重复基因序列为研究对象，运用CondonW 1.4.2分析方格星虫线粒体基因组密码子偏好性参数，通过中性绘图分析、ENC-plot分析、PR2-plot分析及对应分析明确方格星虫线粒体基因组密码子偏好性形成的主导因素，并依据高频密码子和高表达密码子筛选出方格星虫线粒体基因组最优密码子。

【结果】方格星虫线粒体基因组密码子的GC含量因位置而异，GC1、GC2和GC3的平均值分别为51.06%、40.19%和47.11%，GC 含量平均值为46.12%；ENC、CAI和CBI的平均值依次为50.022、0.150和-0.023；RSCU>1.00的同义密码子有31个，以A或C结尾的密码子占87.10%。

中性绘图分析结果表明，GC12与GC3无相关性，相关系数为0.05；ENC-plot分析结果表明，全部参试基因均位于标准曲线下方，说明方格星虫线粒体基因组密码子偏好性以自然选择为主导；PR2-plot分析结果表明，除ND6基因位于左侧x轴上外，其余9个参试基因全部分布在坐标系的第二象限；对应分析结果表明，前4轴的贡献率分别为23.86%、14.96%、12.21%和10.82%，在构建的平面坐标系内细胞色素C类基因分布相对集中，而NADH还原酶类基因分布较分散。

剑桥雅思15阅读 test 4 passage3 题目标题：剑桥雅思15阅读 Test 4 Passage 3 题目解析引言概述：剑桥雅思15阅读 Test 4 Passage 3 是一篇关于动物迁徙的科学文章。

本文将对该题目进行详细解析，包括正文内容和总结，以便读者更好地理解文章的主旨和相关细节。

正文内容：1. 主题介绍1.1 迁徙现象的普遍性1.2 迁徙现象的原因2. 迁徙的影响2.1 生态系统平衡的重要性2.2 迁徙对动物种群的影响2.3 迁徙对环境的影响3. 迁徙的适应性3.1 迁徙路线的选择3.2 迁徙中的食物补充3.3 迁徙中的休息与繁殖4. 迁徙的保护与管理4.1 国际合作与保护项目4.2 迁徙路线的保护4.3 迁徙动物的保护措施5. 迁徙研究的意义5.1 对气候变化的响应5.2 对生物多样性的保护5.3 对人类社会的启示总结：通过对剑桥雅思15阅读 Test 4 Passage 3 的题目解析，我们可以得出以下结论：首先，迁徙现象在动物界普遍存在，并且有多种原因驱使动物进行迁徙。

其次，迁徙对生态系统平衡、动物种群和环境都有重要影响，需要引起足够的重视。

此外，动物在迁徙中表现出了适应性，包括选择迁徙路线、食物补充、休息与繁殖等方面。

为了保护和管理迁徙，国际合作和保护项目是必要的，同时还需要保护迁徙路线和采取相应的保护措施。

最后，迁徙研究对于气候变化、生物多样性保护以及人类社会的发展都具有重要意义。

综上所述，剑桥雅思15阅读 Test 4 Passage 3 题目探讨了动物迁徙的相关问题，这对于我们了解动物行为、生态系统以及环境保护具有重要意义。

我们应该加强对迁徙现象的研究和保护，以确保生态平衡和物种多样性的保护。

发育生物学第一章绪论发育生物学定义：研究生物体从精子和卵子的发生、受精、发育、生长至衰老、死亡的生命过程中的变化机理的学科。

第一节发育生物学的发展与其他学科的关系研究历史很长，1950年左右才形成一门学科，在胚胎学、细胞生物学、遗传学、生物化学、分子生物学的基础上建立的一门新兴学科。

其发展过程：形态描述，机理探讨，从器官→组织→细胞水平→分子水平。

一．胚胎学与发育学胚胎学是发育学发展的基础学科之一。

其发展简史省略（动物胚胎学中细述）描述胚胎学→比较胚胎学→细胞胚胎学→实验胚胎学→分子胚胎学二.遗传学与发育生物学两者密切相关，遗传学的发展促进了发育生物学的研究。

自遗传学家提出“遗传的染色体学说”（Chromosome theory of inheritance）以来，细胞核在发育中的作用受到重视。

Morgan是遗传学家，也为胚胎学家，与他的合作者提出（1926年）“基因理论”（the theory of the gene）1972年，Moore把Morgan遗传概念归纳为12点：1.遗传是由基因从父代传递到子代。

2.基因位于染色体上。

3.每个基因在染色体上占着一个特定的位置。

4.在每个染色体上有很多基因，它们直线排列在染色体上。

5.双倍体生物的体细胞中，每一种染色体有两条（同源染色体），因此每个基因位点（genelocus）有两个。

6.在有丝分裂周期，每一基因也被复制。

7.基因能够以数种不同状态而存在（等位基因），基因从一种状态变为另一种状态就是一个突变。

8.基因在减数分裂时，通过染色体交换能够从一条染色体转移到另一条同源染色体上。

9.每个配子获得每对同源染色体的一条，每条染色体是随机分配到配子中的。

10.每对同源染色体中的一条分配到配子中，不影响其它各对染色体的分配。

11.在受精时，雌雄配子随机结合。

合子从两亲本接受每一对同源染色体中的一条染色体。

12.在一个有机体细胞中包含着两种不同等位基因时，显性基因比隐性基因有较强的表型（phenotype）。