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  • 案例研究结论:从猪到你的流感

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    Swine strain influenza virus particles.
    ::猪流感病毒粒子。

    Case Study Conclusion: Flu, from Pigs to You
    ::案例研究结论:从猪到你的流感

    In April 2009, the world was hit with a swine flu pandemic. The Centers for Disease Control estimates that within that first year, 43 to 89 million people worldwide contracted the swine flu, and that it contributed to between 8,870 and 18,300 deaths. Some people with swine flu were spared serious complications. Eric, who you read about in the beginning of this chapter, was one of the lucky ones. At the time, the swine flu spread rapidly because as a newly evolved viral strain, most people had no natural immunity against it, and the existing flu vaccine could not prevent it. By November 2009, a swine flu vaccine was developed, and now it is included in the annual flu vaccine in the U.S. By August 2010, the World Health Organization declared the H1N1 swine flu pandemic over. The virus is still around, but because of the vaccine and the natural immunity of those who had the virus previously, its infection rate is no longer of pandemic proportions.
    ::2009年4月,世界遭到猪流感大流行的打击。疾病控制中心估计,在第一年,全世界有4,300万至8,900万人感染猪流感,造成8,870至18,300人死亡。一些猪流感患者幸免于严重并发症。在本章开头,你所读到的埃里克是幸运者之一。当时,猪流感迅速蔓延,因为新进的病毒菌株,大多数人没有自然免疫能力,现有流感疫苗也无法预防。到2009年11月,已开发出猪流感疫苗,现在它被列入美国每年的流感疫苗中。到2010年8月,世界卫生组织宣布H1N1猪流感流行。 病毒仍然在附近,但由于疫苗的存在和以前病毒患者的自然免疫力,其感染率已不再是大流行病。

    Swine flu is caused by a specific strain of the influenza virus, as shown in the electron microscope picture above. Like other influenza viruses, it is an RNA virus. This means that it uses RNA instead of DNA as its genetic material. In this sense, RNA viruses may be similar to the earliest living cells on Earth, because they may have also used RNA as their genetic material.
    ::猪流感是由流感病毒的特定菌株引起的,如上文电子显微镜图片所示。与其他流感病毒一样,它是一种RNA病毒。这意味着它使用RNA而不是DNA作为基因材料。 从这个意义上说,RNA病毒可能与地球上最早的活细胞类似,因为它们也可能使用RNA作为基因材料。

    The swine flu virus appears to have originated in pigs, later evolving the ability to infect humans. How could this happen? Scientists think that a process called reassortment played a critical role. In reassortment, influenza viruses can exchange genetic material with each other if they have infected the same cells. This creates new combinations of genes, somewhat similar to the genetic mixing that occurs in sexual reproduction when two parents with different genes reproduce with each other. As you know, genes help dictate the characteristics of an organism, or in this case, a virus. The production of novel combinations of genes due to viral reassortment, therefore, can lead to the evolution of new viral characteristics.
    ::猪流感病毒似乎起源于猪,后来又演变了感染人类的能力。这怎么可能发生?科学家认为所谓的再保障过程具有关键作用。在再保障中,流感病毒可以相互交换基因材料,如果他们感染了相同的细胞。这创造了新的基因组合,与具有不同基因的双亲相互繁殖时在性生殖中出现的基因混合有些相似。如你所知,基因有助于决定一个生物的特性,或在这种情况下,病毒的特性。因此,由于病毒再保障而产生的新基因组合可以导致新的病毒特性的演变。

    In addition to reassortment, influenza viruses have other characteristics that cause them to evolve quickly. In contrast to sexual reproduction, the replication of viruses to produce new “offspring” particles is much more rapid. As you have learned in this chapter, evolution is typically a slow process that takes place over many generations. But if these generations are produced rapidly, as in the case of viruses and bacteria, it speeds the rate of evolution. Additionally, RNA viruses have a very high rate of genetic mutation. As you have learned, mutations are the ultimate source of variation in a gene pool. New alleles are produced through mutations. A high rate of mutation in a virus will therefore increase the rate of evolution, because the characteristics of the virus are rapidly changing. The rapid evolution of the influenza virus is one of the reasons that  the annual seasonal flu vaccine is not always effective against every strain. The viral strains used to make the vaccine are continually evolving.
    ::与性生殖相比,复制病毒产生新的“脱胎”粒子的速度要快得多。正如本章所了解的那样,进化过程通常是代代相传的缓慢过程。但如果这几代人像病毒和细菌一样迅速生产,它就会加快进化速度。此外,RNA病毒的遗传突变率非常高。如你所知,突变是基因集合变化的最终来源。新异种是通过突变产生的。因此,病毒的突变率会提高进化速度,因为病毒的特点正在迅速变化。流感病毒的迅速演变是每年季节性流感疫苗对每种菌株并非总有效的原因之一。用来制造疫苗的病毒菌株正在不断演变。

    But why did this flu pandemic come from pigs? Pigs are actually an ideal “mixing bowl” for the evolution of influenza viruses, because pigs can become infected with influenza viruses from other species, including birds and humans. As a result , genetic reassortment can occur in pigs between viral strains that normally infect different species. This is what scientists think happened  to produce the 2009 H1N1 swine flu virus. The 2009 H1N1 has gene segments from bird, human, and two different pig influenza viruses, and is therefore called a “quadruple reassortant” virus. Genetic mixing between viruses that infect different species is illustrated in the figure below. In the case of the 2009 H1N1, this resulted in a new influenza strain that could infect humans and be passed directly from person to person.
    ::但为什么这种流感大流行来自猪呢?猪实际上是流感病毒进化的理想“混合碗 ” , 因为猪可能会感染其他物种(包括鸟类和人类)的流感病毒。 结果,在病毒菌株(通常感染不同物种的病毒菌株)之间,猪的遗传再配可能发生。 科学家们认为,这就是产生2009年H1N1猪流感病毒的原因。 2009年的H1N1病毒有鸟类、人类和两种不同的猪流感病毒的基因部分,因此被称作“二次重新获得”病毒。 下图说明了感染不同物种的病毒之间的遗传混合。 在2009年的H1N1病毒中,这导致了一种新的流感菌株,可能会感染人类,并直接从人到人。

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    Scientists do not know exactly when and where the 2009 H1N1 evolved, but they think that the reassortment event may have occurred several years prior to the 2009 pandemic. This is based on evidence gathered from “molecular evolution” techniques, which are similar to the molecular clock technique described in this chapter. Influenza viruses are known to mutate at a relatively steady rate. The genetic sequences of the new 2009 H1N1 strain were compared to the sequences in related, older influenza viruses to count the number of new mutations, in order to give an estimate of when the new viral strain evolved.
    ::科学家并不确切知道2009年H1N1在何时何地演化,但他们认为,重新安居事件可能是在2009年大流行之前几年发生的,其依据是“分子进化”技术收集的证据,这些技术类似于本章所述的分子钟技术,已知流感病毒以相对稳定的速率突变。 2009年新的H1N1菌株的遗传序列与相关、旧流感病毒的序列进行了比较,以计算新的突变次数,以便估计新的病毒菌株何时演变。

    Probably one of the final events that resulted in the generation of the 2009 H1N1 virus was contact between North American and Eurasian pigs. P rior to 2009, there were “triple reassortant” variants of H1N1 with gene segments from bird, human, and North American pig influenza already in existence. The 2009 H1N1 strain additionally contained gene segments from influenza from Eurasian pigs, resulting in the “quadruple reassortant” virus. Scientists think that contact between pigs from these different regions, through international trade or other methods of contact, could have created this new strain. As you have learned in this chapter, the migration of organisms to new locations — as well as contact between different organisms — can influence evolution in many ways. Some examples are the migration of ancestral camels throughout the world, the coevolution of flowers and their pollinators, and the “founder effect” of small populations that move to new locations, such as the Amish.
    ::导致2009年H1N1病毒产生的最后事件之一可能是北美猪和欧亚猪之间的接触。在2009年之前,H1N1的“三连累”变种已经存在,其中含有来自鸟类、人类和北美猪流感的基因部分。2009年H1N1还含有来自欧亚猪流感的更多含有的基因部分,导致“横向再获取”病毒。科学家们认为,来自这些不同区域的猪通过国际贸易或其他接触方法的接触,可能造成这种新的菌株。正如你们在本章中所了解到的那样,生物体迁移到新地点以及不同生物体之间的接触可以以多种方式影响演变。一些例子包括世界各地祖先骆驼的迁移、花群及其授粉器的演化以及迁移到新地点(如阿米什人)的小人群的“发现效应 ” 。

    Along with fossils, comparative anatomy and embryology, DNA analysis, and biogeography, evidence for evolution includes the direct observation of it happening . Peter and Rosemary Grant observed evolution occurring in the change in beak size of Galápagos finches. The evolution of the swine flu virus is another example of evolution in action. Evolution is not just a thing of the past — it is an ongoing and important process that affects our ecosystem, species, and even our health. Like viruses, bacteria also evolve rapidly, and the evolution of antibiotic resistance in bacteria is a growing public health concern. You can see that evolution is very relevant to our lives today.
    ::与化石、比较解剖和胚胎学、DNA分析和生物地理学一起,进化的证据包括直接观察它的发生。彼得和罗斯玛丽·格兰特观察到在加拉帕戈斯鳍嘴的大小变化中出现的进化。猪流感病毒的进化是行动演化的另一个例子。进化不仅仅是过去的事情,它是一个持续的重要过程,影响到我们的生态系统、物种,甚至我们的健康。像病毒一样,细菌也迅速演变,细菌抗生素抗药性的进化也日益成为公共卫生问题。你可以看到,进化与我们今天的生活密切相关。

    Chapter Summary
    ::章次摘要

    In this chapter, you learned about the theory of evolution, evidence for evolution, how evolution works, and the evolution of living organisms on Earth. Specifically, you learned:
    ::在本章中,你学到了进化理论,进化的证据,进化是如何运作的, 以及地球上生物体的进化。具体来说,你学到了:

    • Darwin’s theory of evolution by natural selection states that living things with beneficial traits produce more offspring than others do. This leads to changes in the traits of living things over time.
      ::达尔文的自然选择进化理论指出,有有益特性的生活比其他人产生更多后代。 这导致生命特征随时间变化。
      • During his voyage on the  Beagle , Darwin made many observations that helped him develop his theory of evolution, particularly on the Galápagos Islands.
        ::在航行于比格尔岛期间,达尔文提出了许多意见,帮助他发展进化理论,特别是在加拉帕戈斯群岛。
      • Darwin was influenced by other early thinkers, including Lamarck, Lyell, and Malthus. He was also influenced by his knowledge of artificial selection.
        ::达尔文受到其他早期思想家的影响,包括拉马克、莱尔和马尔修斯。他还受到关于人工选择的知识的影响。
      • Wallace’s paper on evolution confirmed Darwin’s ideas. It also pushed him to publish his book,  On the Origin of Species.  The book clearly spells out his theory and provides extensive evidence and well-reasoned arguments to support it.
        ::华莱士关于进化的论文证实了达尔文的想法。 论文还促使他出版了他的书《物种起源》。 书中明确阐述了他的理论,并提供了广泛的证据和理由充分的论点来支持这一理论。

      ::达尔文在比格尔号航行期间提出了许多意见,帮助他发展进化理论,特别是在加拉帕戈斯群岛。达尔文受到其他早期思想家的影响,包括拉马克、莱尔和马尔图斯。他还受到人为选择知识的影响。华莱士关于进化的论文证实了达尔文的想法。它也促使他出版他的书《物种起源》。这本书清楚地阐述了他的理论,并提供了广泛的证据和理由充分的论点来支持这一理论。
    • Fossils provide a window into the past and are evidence for evolution. Scientists who find and study fossils are called paleontologists.
      ::化石是历史的窗口,也是进化的证据。 发现和研究化石的科学家被称为古生物学家。
    • Scientists compare the anatomy, embryos, and DNA of living things to understand how they evolved. Evidence for evolution is provided by homologous structures in related organisms that were inherited from a common ancestor. Other evidence is provided by analogous structures that are structures shared by unrelated organisms, because they evolved for the same function.
      ::科学家比较了生物的解剖学、胚胎和DNA,以了解它们是如何演化的。 相关生物的同质结构从共同祖先继承下来,提供了进化的证据。 类似结构提供了其他证据,这些结构是非关联生物共有的结构,因为它们是为同一功能而演化的。
    • Biogeography is the study of how and why plants and animals live where they do, which provides additional evidence for evolution. On island chains (such as the Galápagos) one species may evolve into many new species to fill available niches. This is called adaptive radiation.
      ::生物地理学是研究植物和动物如何和为什么生活在那里的研究,为进化提供了更多证据。 在岛屿链上(如加拉帕戈斯岛),一种物种可能演变成许多新物种,以填补现有位置。 这被称为适应性辐射。
    • Peter and Rosemary Grant re-studied Galápagos finches. During a drought in the 1970s, they were able to directly observe evolution occurring.
      ::彼得和罗斯玛丽·格兰特重新研究了加拉帕戈斯角。 在1970年代的干旱期间,他们能够直接观察到正在发生的演变。
    • Microevolution refers to evolution that occurs over a relatively short period of time within a population. Macroevolution refers to evolution that occurs at or above the level of species, as the result of microevolution taking place over many generations.
      ::微变是指在人口内部相对较短的时间内发生的演变。 宏观变迁是指在物种水平上或上层发生的演化,这是多代人经历的微变的结果。
    • The population is the unit of evolution, and population genetics is the science that studies evolution at the population level. A population’s gene pool consists of all the genes of all the members of the population. For a given gene, the population is characterized by the frequency of different alleles in the gene pool.
      ::人口是进化的单位,而人口遗传学是研究人口层面演变的科学。 人口基因库由人口所有成员的所有基因组成。 对于特定基因而言,人口特征是基因库中不同基因群的频率。
    • The Hardy-Weinberg theorem states that if a population meets certain conditions, it will be in equilibrium, in which allele and genotype frequencies do not change over time. The conditions that must be met are: no mutation, no migration, very large population size, random mating, and no natural selection.
      ::Hardy-Weinberg理论指出,如果人口符合某些条件,它就会处于平衡状态,在这种平衡状态下,言语和基因型频率不会随时间而变化。 必须满足的条件是:没有突变、没有移徙、人口规模很大、随机交配、没有自然选择。
    • There are four forces of evolution: mutation, which creates new alleles; gene flow, in which migration changes allele frequencies; genetic drift, which is a random change in allele frequencies that may occur in a small population; and natural selection, in which allele frequencies change because of differences in fitness among individuals.
      ::有四种进化力量:突变,它创造了新的变异物;基因流动,其中移徙改变了异变频率;基因漂移,这是在少数人口中可能发生的异变频率的随机变化;自然选择,其中异变频率因个人健康程度的差异而变化。
    • New species arise in the process of speciation. Allopatric speciation occurs when some members of a species become geographically isolated and evolve genetic differences. If the differences prevent them from interbreeding with the original species, a new species has evolved. Sympatric speciation occurs without geographic isolation first occurring.
      ::在物种划分过程中出现了新物种,当某一物种的某些成员在地理上与世隔绝并演变成遗传差异时,就出现了异族血统的特征,如果差异阻止他们与原始物种发生血缘关系,新物种就会演变。
    • Coevolution occurs when interacting species evolve together. One example is flowering plants and their pollinators.
      ::当相互作用的物种一起演变时,就会发生革命。一个例子是开花植物及其授粉者。
    • Darwin thought that evolution occurs steadily and gradually. This model of evolution is called gradualism. The fossil record better supports the model of punctuated equilibrium. In this model, long periods of little change are interrupted by bursts of relatively rapid change.
      ::达尔文认为进化是稳定而渐进的。 这种进化模式被称为渐进。 化石记录更好地支持标点平衡模式。 在这个模式中, 长期的微小变化会因相对快速的变化而中断。
    • The fossil record is the record of life on Earth as reconstructed from the discovery and analysis of fossils. It is one of the most important tools in the study of evolution, but it is incomplete, because fossilization is rare. To be added to the fossil record, fossils must be dated using relative or absolute dating methods.
      ::化石记录是地球上从发现和分析化石中重建出来的生命记录。 它是研究进化的最重要工具之一,但不完整,因为化石化是罕见的。 要补充化石记录,化石必须使用相对或绝对的约会方法注明日期。
    • Molecular clocks are additional tools for reconstructing how life on Earth evolved. Molecular clocks use DNA or protein sequences to estimate how much time has passed since related species diverged from a common ancestor. 
      ::分子钟是重建地球上生命如何演变的又一个工具。 分子钟使用DNA或蛋白质序列来估计相关物种与共同祖先分离后已经过了多少时间。
    • The geologic time scale is a timeline of Earth's history. It divides Earth's chronology into smaller units of time, such as eons and eras that are based on major changes in geology, climate, and living things.
      ::地质时间尺度是地球历史的一个时间轴。它将地球的年表分为较小的时间单位,例如以地质、气候和生物物质的重大变化为基础的延时和时代。
    • Earth formed 4.5-4.6 billion years ago. At first, Earth was molten and lacked an atmosphere and oceans. Gradually, the atmosphere formed, followed by the oceans.
      ::地球在45—46亿年前形成。最初,地球被熔化,没有大气层和海洋。逐渐形成,然后是海洋。
    • The first organic molecules probably formed by four billion years ago. This may have happened when lightning sparked chemical reactions in Earth’s early atmosphere. RNA may have been the first organic molecule to form. It was also  the basis of early life.
      ::最早的有机分子可能是40亿年前形成的。 这可能是当闪电在地球早期大气中引发化学反应时发生的。 RNA可能是最早形成的有机分子。 这也是早期生命的基础。
    • The first cells consisted of little more than an organic molecule such as RNA inside a lipid membrane. One cell, called the last universal common ancestor (LUCA), gave rise to all subsequent life on Earth.
      ::最初的细胞只包括一种有机分子,如脂质膜内的RNA。 一个叫做最后一个世界性共同祖先的细胞(LUCA ) , 产生了地球上所有随后的生命。
    • Photosynthesis evolved by three billion years ago, releasing oxygen into the atmosphere. Aerobic cellular respiration — which made use of the oxygen — evolved after that.
      ::光合作用在30亿年前演化,释放氧气到大气中。 之后,利用氧气的有氧细胞呼吸也随之演变。
    • Eukaryotic cells probably evolved about two billion years ago. Their evolution is explained by endosymbiotic theory.
      ::20亿年前,欧洲内分泌细胞可能进化了。它们的进化是由内生理论解释的。
    • During the late Precambrian, continents drifted, carbon dioxide levels fluctuated, and climates changed. Many organisms could not survive the changes and died out. Others evolved important new adaptations, including sexual reproduction, cell specialization, and multicellularity. The Precambrian ended with a mass extinction, paving the way for the Cambrian explosion.
      ::在已故的Precambrian期间,大陆漂移,二氧化碳水平波动,气候变化。 许多生物体无法承受变化并死亡。 另一些则发展了重要的新适应措施,包括性生殖、细胞专业化和多细胞性。 普雷坎布里安以大规模灭绝告终,为坎布里安爆炸铺平了道路。
    • The Paleozoic Era began with the Cambrian explosion and ended with the Permian extinction. During this era, invertebrate animals diversified in the oceans. Plants, amphibians, and reptiles also moved to the land.
      ::Paleozoic Eraa以Cambrian爆炸开始,以Permian灭绝结束。在这个时代,无脊椎动物分散在海洋中,植物、两栖动物和爬行动物也移到了陆地上。
    • The Mesozoic Era was the age of dinosaurs. They evolved from reptiles to occupy the land, water, and air. Mammals also evolved, but were small in size, and flowering plants appeared for the first time. Dinosaurs went extinct at the end of the Mesozoic Era.
      ::中祖时代是恐龙时代,它们从爬行动物演变为占据土地、水和空气。哺乳动物也进化了,但体积较小,开花植物首次出现。 恐龙在中祖时代末期灭绝了。
    • The Cenozoic Era, or era of "modern life," began about 65 million years ago and continues to the present. The Cenozoic is called the age of mammals because of the diversification and importance of mammals during this era.
      ::现代生命时代(Cenozoic Era)是大约6500万年前开始并一直延续至今的“现代生命”时代。 基因时代被称为哺乳动物时代,因为哺乳动物在这个时代的多样性和重要性。
      • During the Cenozoic Era, the continents moved to their present positions, and Earth's climate became cooler and drier. These changes had a major impact on the evolution of life during the era.
        ::在Cenozoic时代,各大洲移到了目前的位置,地球的气候变得更冷和更干燥。 这些变化对时代生命的演变产生了重大影响。
      • Today, the Cenozoic Era is generally subdivided into three periods, called  the Paleogene, Neogene, and Quaternary (or Anthropogene) Periods. 
        ::今天,Cenozoic时代一般分为三个时期,称为Paleogene、Neogene和量代(或人代)时期。
      • The three periods of the Cenozoic Era are subdivided into seven epochs. The Paleogene Period includes the Paleocene, Eocene, and Oligocene Epochs. The Neogene Period includes the Miocence and Pliocene Epochs. The Quaternary Period includes the Pleistocene and Holocene (current) Epochs.
        ::Cenozoic时代的三个时期细分为7个时期,帕列奥金时期包括帕莱克辛、埃奥辛和奥利戈塞埃波赫,内奥金时期包括米奥辛和普利奥辛埃波赫,四年度期间包括Pleistocene和Hlocene(当前)埃波奇。

      ::在Cenozoic Era 期间,各大洲移到了目前的位置,地球的气候变得更冷和更干,这些变化对这个时代的生活演变产生了重大影响。今天,Cenozoic Era 通常分为三个时期,称为Paleogene、Neogene和Quaternary(或人类基因)时期。Cenozoic Era 的三个时期又细分为7个时期。Paleogene时期包括Paleocene、Eocene和Oligocene Epochs。Negene时期包括Miocente和Pliocene Epochs。 Quateralary时期包括Pleistocene和Holocene(流动)Epochs。
    • The earliest primates evolved in the Paleocene Epoch; apes diversified during the Miocene Epoch; and close human relatives called Australopithecines evolved during the Pliocene Epoch. The Cenozoic cooling trend culminated in an ice age during the Pleistocene Epoch, which is also the epoch during which the human genus  (Homo)  and human species  (Homo sapiens ) evolved. Human beings became ascendant, and all of recorded human history occurred during the Holocene Epoch.
      ::最早的灵长类动物在Paleocene Epoch进化;人猿在 Miocene Epoch期间多样化;近亲称为Australoptithecine在Pliocene Epoch 进化。在Pleistocene Epoch 进化到冰河期,这个时代也是人类基因(Homo)和人类物种(Homo sapiens)进化的时代。人类成为上层生物,所有记录下来的人类历史都发生在Holocene Epoch期间。

    Now that you have learned about evolution and how life on Earth evolved, the next chapter will delve deeper into the specifics of how our species evolved to become what it is today.
    ::既然你们已经了解了进化过程 以及地球上的生命是如何进化的 下一章将深入探讨 我们物种是如何进化成今天的

    Chapter Summary Review
    ::" 概述 " 章次

    lesson content

    Evolution of Beak Size in Galápagos Finches
    ::加拉帕戈斯芬奇鸟嘴大小的演变

    1. Data from Peter and Rosemary Grant’s study on the evolution of beak size in Galápagos finches is shown above. The top graph (1976) shows the distribution of beak size in the population before a drought, and the bottom graph (1978) shows beak size after the drought. The drought reduced seed availability. Finches with big beaks can crack open and eat seeds of all sizes, while finches with small beaks can only crack open and eat small seeds. Answer the following questions about this data.
    ::1. 彼得和罗斯玛丽·格兰特关于加拉帕戈斯雀巢嘴大小演变的研究数据见上文,上图(1976年)显示干旱前海嘴面积在人口中的分布情况,下图(1978年)显示干旱后海嘴面积的分布情况,干旱减少了种子的可得性,大嘴的芬奇可以开口吃各种大小的种子,而小嘴的鳍只能开口吃小种子,回答以下关于这一数据的问题。

    a. How was the average beak size affected by the drought? Although scientists would calculate this mathematically, you may answer just based on your observation of the graphs.
    ::a. 受干旱影响的平均嘴嘴大小如何?虽然科学家会用数学来计算,但你可以根据对图表的观察来回答。

    b. Explain how natural selection and the “struggle for existence” likely changed the beak size in this population.
    ::b. 解释自然选择和 " 生存之争 " 如何可能改变这一人群的嘴唇大小。

    c. Is this an example of microevolution or macroevolution? Explain your answer.
    ::c. 这是微观进化还是宏观进化的例子?解释你的答复。

    d. Explain why variation is important for evolution by natural selection, using the data above as a specific example.
    ::d. 以上述数据为具体例子,解释为什么变化对自然选择的演变很重要。

    e. What do you notice about the distribution of beak sizes in the 1978 graph — are all the beaks one size? If not, why not?
    ::e. 关于1978年图表中嘴嘴大小的分布,你注意到什么?所有嘴都是一码吗?如果没有,为什么不呢?

    f. Is the change in beak size shown here an example of stabilizing selection, disruptive selection, or directional selection?
    ::f. 这里显示的嘴唇大小变化是否是稳定选择、干扰选择或定向选择的实例?

    2. Which of the following is an example of macroevolution?
    ::2. 以下哪些是宏观演变的例子?

    a. speciation
    ::a. 区划

    b. coevolution
    ::b. 共同演变

    c. structures that become larger in a population
    ::c. 人口规模扩大的结构

    d. A and B
    ::d. A和B

    3. Speciation is:
    ::3. 特征为:

    a. the movement of a species to a new niche
    ::a. 物种向新位置的移动

    b. evolution that occurs within a species
    ::b. 物种内部发生的演变

    c. the evolution of a new species from an existing species
    ::c. 现有物种中新物种的演变

    d. the development of analogous structures
    ::d. 发展类似结构

    4. True or False:  An individual’s genotype is known as their gene pool.
    ::4. 真实或假:一个人的基因型被称为他们的基因库。

    5. True or False:  New species can evolve without geographic separation.
    ::5. 真实的或虚假的:新物种可以在不进行地理分离的情况下演变。

    6. True or False:  In punctuated equilibrium, the periods of relatively little evolutionary change are shorter than the periods of dramatic change.
    ::6. 真实的或虚假的:在无孔不入的平衡中,进化变化相对较少的时期短于急剧变化的时期。

    7. Describe one example of a major environmental change that influenced the evolution of life on Earth. This change could include climate change, geologic change, change in existing species, change in the atmosphere, etc.
    ::7. 描述影响地球上生命演变的重大环境变化的一个例子,这种变化可包括气候变化、地质变化、现有物种变化、大气变化等。

    8. Explain why mass extinction events often cause rapid evolutionary changes afterwards.
    ::8. 解释大规模灭绝事件往往导致随后迅速演变变化的原因。

    9. In which epoch did our species, Homo sapiens , evolve?
    ::9. 我们的人类智人在哪个时代进化?

    10. Since dinosaurs evolved from reptiles, explain why reptiles still exist.
    ::10. 由于恐龙从爬行动物演变而来,所以解释为什么爬行动物仍然存在。

    11. Are s pecies with homologous structures more or less  likely to be closely related than species with analogous structures?
    ::11. 具有同族结构的物种是否可能与具有类似结构的物种或多或少密切相关?

    12. Explain why fossils of extinct animals provide evidence for evolution.
    ::12. 解释为什么灭绝动物的化石为进化提供了证据。

    13. Imagine you are on a paleontology dig, excavating a site from the Jurassic Period.
    ::13. 想象一下,你在古生物学挖掘中 挖掘了侏罗纪时期的一个遗址。

    a. Which of the following organisms would you be unlikely to find fossils for? Explain your answer.
    ::a. 下列生物中,哪些是不可能找到化石的?解释你的答复。

                birds; mammals; primates; dinosaurs
    ::鸟类;哺乳动物;灵长类动物;恐龙

    b. What method could you use to determine the age, in years, of a fossil that you find?
    ::b. 您可以使用何种方法确定你发现的化石年限?

    c. What type or types of material would you need to find if you wanted to use the molecular clock method? Explain your answer.
    ::c. 如果要使用分子钟法,需要找到何种类型的材料?解释你的答复。

    14. Put the following organisms in order of when they first evolved, from the earliest to the most recent:
    ::14. 将以下有机体按它们最初从最早到最近首次进化的顺序排列如下:

    trilobites; dinosaurs; eukaryotes; birds; primates; prokaryotes
    ::三洛虫;恐龙;木卫三;鸟类;灵长类;原虫

    15. Which of the following is an example of evolution by natural selection?
    ::15. 以下哪些是自然选择的演变实例?

    a. humans breeding dogs for certain characteristics
    ::a. 某些特性的人类养狗犬

    b. bats developing wings as an adaptation for flight
    ::b. 发展翅膀以适应飞行的蝙蝠

    c. A and B
    ::c. A和B

    d. none of the above
    ::d. 以上无任何内容

    16. Compare and contrast Darwin’s theory of evolution by natural selection with  Lamarck’s idea of inheritance of acquired characteristics.
    ::16. 将达尔文的自然选择进化理论与拉马克对既得特征的继承概念进行比较和对比。

    17. Explain how microevolution and macroevolution relate to each other.
    ::17. 解释微观进化和宏观进化是如何相互联系的。

    18. The fact that embryonic humans have gill slits is evidence for:
    ::18. 胚胎人类有刺断的情况证明:

    a. coevolution
    ::a. 共同演变

    b. evolution of analogous structures
    ::b. 类似结构的演变

    c. common ancestry of vertebrates
    ::c. 脊椎动物的共同祖先

    d. gene flow
    ::d. 基因流动

    19. The study of allele frequencies in a group of the same species in the same time and place is known as _________ genetics.
    ::19. 在同一时间和同一地点研究同一物种群中的异频,称为遗传学。

    20. Explain how biogeography can be used to study adaptive radiation.
    ::20. 解释如何利用生物地理学研究适应性辐射。

    21. Put the following eras in order from earliest to latest:
    ::21. 将下列时代从最早的到最晚的顺序排列为:

    Cenozoic; Paleozoic; Mesozoic
    ::Cenozoic;Paleozoic;Mesozoic

    22. The Triassic, Jurassic, and Cretaceous periods are part of the:
    ::22. Triassic、Jurassic和白鲸时期是:

    a. Mesozoic Era
    ::a. 中共时代

    b. Cenozoic Era
    ::b. 精神分裂时代(Cenozoic Eraa)

    c. Paleocene Epoch
    ::c. 帕莱克辛埃波克

    d. Pliocene Epoch
    ::d. Plicucene Epoch 设备

    23. Put the following in order from broadest division to smallest subdivision:
    ::23. 从最广的分区到最小的分区排列如下:

    period; eon; epoch; era
    ::周期; eon; 时代; 时代

    24. Gene flow occurs when...
    ::24. 源流发生于...

    a. individuals migrate into a population
    ::a. 移徙人口

    b. individuals migrate out of a population
    ::b. 从人口迁移出的人口

    c. a bottleneck effect occurs
    ::c. 发生瓶颈效应

    d. both A and B
    ::d. A 和 B 两者

    25. Explain why mutations disrupt Hardy-Weinberg equilibrium.
    ::25. 解释为何突变扰乱了哈代温伯格的平衡。