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  • General

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  • 阴道和克拉底主义

    What you will learn
    ::你会学到什么

    • What is phylogeny and phylogenetic
      ::什么是植物和植物遗传学
    • What is a clade and how is it represented 
      ::什么是刀片,它是如何代表的?

    Various mammals including a lion, elephant, tiger, horse, and more, illustrating species diversity.

    Can two different species be related?
    ::能否将两种不同的物种联系起来?

    Of course they can. For example, there are many different of mammals , or of one type of mammal, such as mice. And they are all related. In other words, how close or how far apart did they separate from a common ancestor during evolution? Determining how different species are evolutionarily related can be a tremendous task.
    ::当然,它们可以。例如,哺乳动物或一种哺乳动物(如小鼠)有许多不同的种类。它们都是相互关联的。换句话说,它们与一个共同的祖先在进化过程中的距离有多近或多远?确定不同的物种在进化过程中是如何相联的,可以是一项巨大的任务。

    Phylogenetic Classification
    ::生代遗传学分类

    Linnaeus classified organisms based on obvious physical traits. Basically, organisms were grouped together if they looked alike. After published his theory of evolution in the 1800s, scientists looked for a way to classify organisms that showed phylogeny. Phylogeny is the evolutionary history of a group of related organisms. It is represented by a phylogenetic tree , like the one in Figure .
    ::Linnaeus根据明显的物理特征对生物进行分类。基本上,生物如果看起来相似,就会被归为一组。在1800年代发表了他的进化理论后,科学家们寻找了一种方法对表现出植物本性的生物进行分类。 菲亚基是一组相关生物的进化史。 它由一棵植物树(如图中所示的树)代表。

    A phylogenetic tree showing relationships among three hypothetical species.
    Phylogenetic Tree. This phylogenetic tree shows how three hypothetical species are related to each other through common ancestors. Do you see why Species 1 and 2 are more closely related to each other than either is to Species 3?

    One way of classifying organisms that shows phylogeny is by using the clade. A clade is a group of organisms that includes an ancestor and all of its descendants. Clades are based on cladistics . This is a method of comparing traits in related species to determine ancestor-descendant relationships. Clades are represented by cladograms , like the one in Figure . This cladogram represents the mammal and clades. The reptile clade includes . It shows that birds evolved from reptiles. Linnaeus classified mammals, reptiles, and birds in separate classes. This masks their evolutionary relationships.
    ::一种对生物进行分类的方法是使用刀片来对显示血原的生物进行分类。 刀片是一组有机体, 包括祖先及其所有后代。 刀片以单片为基础。 这是比较相关物种特性以确定祖先- 后代关系的一种方法。 刀片用单形图来表示, 如图中的单形图一样。 单形图代表哺乳动物和冰丝。 爬虫片包括。 它显示鸟类从爬行动物中演变。 林瑙斯将哺乳动物、爬行动物和鸟类分为不同的类别。 这掩盖了它们的进化关系 。

    Cladogram illustrating evolutionary relationships among mammals, reptiles, and birds, highlighting their clades.
    This cladogram classifies mammals, reptiles, and birds in clades based on their evolutionary relationships.

     

     

     

     

    DID YOU KNOW?
    Phenetics or numerical taxonomy was another popular classification method during the mid-twentieth century. This method classified organisms based on similarities of observable or morphological traits. The phylogenetic method of classifying organisms includes heritable traits such as and sequences. 
     

     

     

     

     

    Summary
    ::摘要

    • Phylogeny is the evolutionary history of group of related organisms. It is represented by a phylogenetic tree that shows how species are related to each other through common ancestors.
      ::Phylgeny是相关生物群的进化历史,由一棵植物基因树代表,它表明物种通过共同祖先如何相互联系。
    • A clade is a group of organisms that includes an ancestor and all of its descendants. It is a phylogenetic classification, based on evolutionary relationships.
      ::克莱德是一种有机体,包括祖先及其后代,是一种基于进化关系的植物基因分类。

    Review
    ::回顾

    1. What is a clade?
      ::什么是克莱德?
    2. What is cladistics, and what is it used for?
      ::什么是单词,它用于什么?
    3. Explain why reptiles and birds are placed in the same clade.
      ::解释为什么爬行动物和鸟类 被放在同一个克莱里。
    4. Dogs and wolves are more closely related to each other than either is to cats. Draw a phylogenetic tree to show these relationships.
      ::狗和狼比猫更紧密地联系在一起。 画一棵植物基因树来展示这些关系。