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  • 进进理论理论理论

    What you will learn
    ::你会学到什么

    • How was influenced by the work of Lamarck , Malthus , and Lyell
      ::如何受到Lamarck、Malthus和Lyell作品的影响
    • Darwin’s theory of evolution by natural selection 
      ::达尔文自然选择的进化理论

    Charles Darwin's concept of species divergence and common ancestry.

    How do new species form?
    ::新的物种如何形成?

    This is the only illustration in Charles Darwin's 1859 book On the Origin of , showing his ideas describing the divergence of species from common ancestors .
    ::这是查尔斯·达尔文1859年的《起源》一书中唯一的例证,其中展示了他描述物种与共同祖先差异的想法。

    Darwin’s Theory of Evolution by Natural Selection
    ::达尔文的自然选择演变理论

    Darwin spent many years thinking about the work of Lamarck, Lyell, and Malthus, what he had seen on his voyage, and artificial selection . What did all this mean? How did it all fit together? It fits together in Darwin’s theory of evolution by natural selection . It’s easy to see how all of these influences helped shape Darwin’s ideas.
    ::达尔文花了多年时间思考了拉马克、莱尔和马尔萨斯的工作、他在航行上所看到的以及人为选择。 这到底意味着什么? 这一切又怎样? 如何融合在一起? 它符合达尔文自然选择的进化理论。 很容易看出所有这些影响是如何帮助达尔文形成思想的。

    Evolution of Darwin’s Theory
    ::达尔文理论的演变

    It took Darwin years to form his theory of evolution by natural selection. His reasoning went like this:
    ::达尔文花了几年时间通过自然选择来形成他的进化理论。他的推理是这样的:

    1. Like Lamarck, Darwin assumed that species can change over time. The he found helped convince him of that.
      ::达尔文和拉马克一样 认为物种可以随时间变化
    2. From Lyell, Darwin saw that Earth and its life were very old. Thus, there had been enough time for evolution to produce the great diversity of life Darwin had observed.
      ::达尔文从莱尔(Lyell)那里看到,地球及其生命都非常古老。 因此,有充足的时间来进行进化,以产生达尔文观察到的丰富多彩的生命。
    3. From Malthus, Darwin knew that could grow faster than their resources. This “overproduction of offspring” led to a “struggle for existence,” in Darwin’s words.
      ::达尔文从马尔萨斯(Malthus)那里知道,这比他们的资源增长得更快。 达尔文(Malthus)用达尔文的话来说,“后代的过度生产”导致了“生存之争 ” 。
    4. From artificial selection, Darwin knew that some offspring have variations that occur by chance, and that can be inherited. In nature, offspring with certain variations might be more likely to survive the “struggle for existence” and reproduce. If so, they would pass their favorable variations to their offspring.
      ::达尔文从人工选择中知道,某些后代的变异是偶然发生的,并且可以传承。 在自然界,具有某些变异的后代更有可能在“为生存而挣扎”和繁殖中存活下来。 如果是这样的话,他们会把有利的变异传给后代。
    5. Darwin coined the term fitness to refer to an organism’s relative ability to survive and produce fertile offspring. Nature selects the variations that are most useful. Therefore, he called this type of selection .
      ::达尔文创造了“适合”一词,以指生物体的生存和生育生育后代的相对能力。自然选择最有用的变异。因此,他称之为“选择 ” 。
    6. Darwin knew artificial selection could change domestic species over time. He inferred that natural selection could also change species over time. In fact, he thought that if a species changed enough, it might evolve into a new species.
      ::达尔文知道人为选择会随着时间的推移改变国内物种。 他推断自然选择也会随时间而改变物种。 事实上,他认为如果物种变化足够多,它可能会演变成新的物种。

    Wallace’s paper not only confirmed Darwin’s ideas. It also pushed him to finish his book, On the Origin of Species . Published in 1859, this book changed science forever. It clearly spelled out Darwin’s theory of evolution by natural selection and provided convincing arguments and evidence to support it.
    ::华莱士的论文不仅证实了达尔文的想法,还促使他完成《物种起源》一书。 1859年出版的这本书永远改变了科学。 它通过自然选择明确阐述了达尔文的进化理论,并提供了令人信服的论据和证据来支持它。

    Applying Darwin’s Theory
    ::应用达尔文的理论

    The following example applies Darwin’s theory. It explains how giraffes came to have such long necks (see Figure ).
    ::以下的例子应用达尔文的理论。 它解释了长颈鹿是如何长脖子的(见图 )。

    • In the past, giraffes had short necks. But there was chance variation in neck length. Some giraffes had necks a little longer than the average.
      ::过去,长颈鹿的颈部短短,但颈部有可能会变化,有些长颈鹿的颈部比平均长一点。
    • Then, as now, giraffes fed on tree leaves. Perhaps the environment changed, and leaves became scarcer. There would be more giraffes than the trees could support. Thus, there would be a “struggle for existence.”
      ::那时,象现在一样,长颈鹿以树叶为食,也许环境改变了,叶子更加稀少。 长颈鹿将比树木所能支撑的还要多。 因此,将有一种“为生存而奋斗 ” 。
    • Giraffes with longer necks had an advantage. They could reach leaves other giraffes could not. Therefore, the long-necked giraffes were more likely to survive and reproduce. They had greater fitness.
      ::长颈长颈的长颈鹿有一个优势,它们可以伸到其他长颈鹿的叶子上。 因此,长颈长颈的长颈鹿更有可能存活和繁殖。 它们更健康。
    • These giraffes passed the long-neck trait to their offspring. Each generation, the population contained more long-necked giraffes. Eventually, all giraffes had long necks.
      ::这些长颈鹿将长颈鹿的特征传给后代。 每一代人中,都含有长颈长颈鹿。 最后,所有长颈鹿都有长颈鹿。
    Four-step illustration showing giraffe evolution: variation, struggle, fitness, and trait increase.
    Evolution of long-neck giraffes: Example of Darwin's Theory of Evolution by Natural Selection.

    As this example shows, chance variations may help a species survive if the environment changes. Variation among species helps ensure that at least one will be able to survive environmental change.
    ::如这个例子所示,如果环境发生变化,机会的变化可能会帮助物种生存下去。 物种之间的差异有助于确保至少有一个物种能够生存下去。

     

     

    KQED: Chasing Beetles, Finding Darwin
    ::KQED: 捕猎甲虫,寻找达尔文

    It's been over 150 years since Charles Darwin published On the Origin of Species . Yet his ideas remain as central to scientific exploration as ever, and has been called the unifying concept of all biology . Is evolution continuing today? Of course it is.
    ::自查尔斯·达尔文发表《物种起源》以来,150多年已经过去了。然而,他的想法仍然一如既往地成为科学探索的中心,并被称为所有生物学的统一概念。进化今天是否还在继续?当然,它也是。

    QUEST follows researchers who are still unlocking the mysteries of evolution, including entomologist David Kavanaugh of the California Academy of Sciences, who predicted that a new beetle species would be found on the Trinity Alps of Northern California. 
    ::QUEST跟踪那些仍在解开进化奥秘的研究人员,包括加利福尼亚科学院昆虫学家David Kavanaugh,他预测在北加利福尼亚的三一阿尔卑斯山上会发现一个新的甲虫物种。

    It's rare for a biologist to predict the discovery of a new species. For his prediction , Kavanaugh drew inspiration from Darwin's own 1862 prediction. When Darwin observed an orchid from Madagascar with a foot-long nectar , he predicted that a pollinator would be found with a tongue long enough to reach the nectar inside the orchid's very thin, elongated nectar ‘‘pouch’’, though he had never seen such a or insect. Darwin's prediction was based on his finding that all species are related to each other and that some of them evolve together, developing similar adaptations . Darwin's prediction came true in 1903, when a moth was discovered in Madagascar with a long, thin proboscis , which it uncurls to reach the nectar in the orchid's nectar. In the process of feeding from the orchid, the moth serves as its pollinator. The moth was given the scientific name Xanthopan morganii praedicta , in honor of Darwin’s prediction.   
    ::生物学家很少能预测新物种的发现。 在他的预测中, Kavanaugh从达尔文自己的1862年预测中获得了灵感。 当达尔文用一英尺长的花蜜观察了马达加斯加的兰花时,他预测说授粉者将找到一个舌头足够长的授粉者,可以到达兰花非常薄的花蜜,尽管他从未见过这种花蜜或昆虫。达尔文的预测是基于他发现所有物种都相互关联,其中一些物种一起演变,形成类似的适应性。达尔文的预测在1903年就成真了,当时在马达加斯加发现了一只长而薄的飞蛾,它无法到达兰花的花蜜。在从兰花的喂养过程中,飞蛾是它的授粉者。为了纪念达尔文的预测,它被授予了科学名称Xanthopan morganii raedicta。

     

     

    As you view Chasing Beetles, Finding Darwin, focus on the following concepts:
    ::当你们看到猎物甲虫, 寻找达尔文, 集中关注以下概念:

    1. the relationship between studying beetles and evolution,
      ::研究甲虫和进化之间的关系,
    2. the of new species,
      ::和新物种,
    3. the relationship between genetic make-up of an organism and evolution,
      ::生物体的基因构成与进化之间的关系,
    4. the role of beneficial ,
      ::发挥有益、有益和有益的作用,
    5. the role of ‘‘ habitat islands’’,
      ::哈比塔群岛的作用,
    6. the selection for certain traits among breeders, such as pigeon breeders,
      ::为种鸽类等育种者所选的某些特性,
    7. the importance of identifying new species.
      ::确定新物种的重要性。

    Science Friday : Sex, Lies and Orchids
    ::星期五:性、谎言和兰花

    Orchids utilize a wide variety of techniques to manipulate other species into becoming their pollinators. In this video by Science Friday , curator Marc Hachadourian describes some of these deceptive methods.
    ::兰花利用多种技术操纵其他物种成为授粉者。 在科学星期五的这段视频中,馆长马克·哈查杜里安描述了其中的一些欺骗性方法。

     

     

     

    Summary
    ::摘要

    • Darwin's book On the Origin of Species clearly spells out his theory.
      ::达尔文的《物种起源》一书清楚地阐述了他的理论。
    • Darwin's book also provides evidence and logic to support that evolution occurs and that it occurs by natural selection.
      ::达尔文的书也提供了证据和逻辑 支持进化的发生 以及自然选择的演变

    Review
    ::回顾

    1. Define fitness.
      ::界定身体健康。
    2. Apply Darwin’s theory of evolution by natural selection to a specific case. For example, explain how Galápagos tortoises could have evolved saddle-shaped shells.
      ::通过自然选择将达尔文的进化理论应用到特定案例中。 比如,解释加拉帕戈斯的乌龟是如何进化成马鞍形贝壳的。
    3. Explain how the writings of Charles Lyell and Thomas Malthus helped Darwin develop his theory of evolution by natural selection.
      ::解释一下查尔斯·莱尔和托马斯·马尔图斯的著作如何帮助达尔文通过自然选择来发展他的进化理论。
    4. Discuss the role artificial selection had on Darwin's theory.
      ::讨论达尔文理论中 人为选择的角色

    Resources    
    ::资源