章节大纲

  • 常规

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  • 生物地球学

    What you will learn
    ::你会学到什么

    • How has geography influenced the evolution of plants and
      ::地理如何影响植物和植物的进化?
    • Examples of biogeography that provide evidence for evolution
      ::为演变提供证据的生物地理学实例

    A map of the world highlighting continents in yellow.

    Why would geography have anything to do with evolution?
    ::为什么地理与进化有关?

    Similar to "how did the chicken cross the road?" but on a much grander scale. How did the animal cross Europe and into Asia? Or Asia into America? How did anything get into Australia?
    ::与“鸡是怎么过马路的?”相似,但规模更大。动物如何横跨欧洲和亚洲?还是亚洲进入美洲?什么进入澳大利亚?

    Evidence from Biogeography
    ::来自生物地球学的证据

    Biogeography is the study of how and why plants and animals live where they do. It provides more evidence for evolution. Let’s consider the camel family as an example.
    ::生物地理学是研究植物和动物如何以及为什么生活在它们所生活的地方。 它为进化提供了更多的证据。 让我们把骆驼家庭当作一个例子。

    Biogeography of Camels: An Example
    ::Cames生物地理学:实例

    Today, the camel family includes different types of camels. They are shown in Figure . All of today’s camels are descended from the same camel ancestors . These ancestors lived in North America about a million years ago.
    ::今天,骆驼家庭包括不同类型的骆驼,图中显示了这些例子。 今天所有的骆驼都是来自同一批骆驼祖先的后裔。 这些祖先大约在一百万年前就生活在北美。

    Map showing migration paths of camels with photos of Dromedary, Bactrian camels, and Llama.
    Camel Migrations and Present-Day Variation. Members of the camel family now live in different parts of the world. They differ from one another in a number of traits. However, they share basic similarities. This is because they all evolved from a common ancestor. What differences and similarities do you see?

    Early North American camels migrated to other places. Some went to East Asia. They crossed a land bridge during the last ice age. A few of them made it all the way to Africa. Others went to South America. They crossed the Isthmus of Panama. Once camels reached these different places, they evolved independently. They evolved adaptations that suited them for the particular environment where they lived. Through , descendants of the original camel ancestors evolved the diversity they have today.
    ::北美早期的骆驼迁移到其他地方,有些迁移到东亚,在上一个冰河时代穿越了一座陆地桥,有些穿越了非洲,另一些则穿越了南美洲,越过了巴拿马的地峡。骆驼到达了这些不同的地方后,它们就独立地演变了。它们演变了适合它们居住的特殊环境的适应措施。通过这些办法,原始骆驼祖先的后代发展了今天的多样性。

    Island Biogeography
    ::岛屿生物地理学

    The biogeography of islands yields some of the best evidence for evolution. Consider the called finches that studied on the Galápagos Islands (see Figure ). All of the finches probably descended from one bird that arrived on the islands from South America. Until the first bird arrived, there had never been birds on the islands. The first bird was a seed eater. It evolved into many finch . Each species was adapted for a different type of food . This is an example of adaptive radiation . This is the process by which a single species evolves into many new species to fill available niches.
    ::岛屿生物地理学为进化提供了一些最佳证据。 想想加拉帕戈斯群岛上研究的所谓“ 鳍”(见图 ) 。 所有鳍可能都来自来自来自南美的一只鸟类。 在第一批鸟类抵达之前,群岛上从未出现过鸟类。 第一只鸟类是种子食用者, 演变成许多大小。 每个物种都适应了不同种类的食物。 这是适应性辐射的一个例子。 这是单个物种演变成许多新物种以填补现有位置的过程。

    Darwin's finches showing adaptive radiation for different food sources.
    Galápagos finches differ in beak size and shape, depending on the type of food they eat.

    Eyewitness to Evolution
    ::演变的目击者

    In the 1970s, biologists Peter and Rosemary Grant went to the Galápagos Islands. They wanted to re-study Darwin’s finches. They spent more than 30 years on the project. Their efforts paid off. They were able to observe evolution by natural selection actually taking place.
    ::1970年代,生物学家彼得和罗斯玛丽·格兰特前往加拉帕戈斯群岛。 他们想重新研究达尔文的鳍。 他们花了30多年的时间在这个项目上,他们的努力取得了成效。 他们能够通过自然选择观察进化。

    While the Grants were on the Galápagos, a drought occurred. As a result, fewer seeds were available for finches to eat. Birds with smaller beaks could crack open and eat only the smaller seeds. Birds with bigger beaks could crack and eat seeds of all sizes. As a result, many of the small-beaked birds died in the drought. Birds with bigger beaks survived and reproduced (see Figure ). Within 2 years, the average beak size in the finch increased. Evolution by natural selection had occurred.
    ::当赠款在加拉帕戈斯岛时,发生了干旱,因此,可食用雀巢的种子减少了,小嘴鸟可以开口吃小种子,大嘴鸟可以开口吃各种大小的种子,大嘴鸟可以开口吃各种大小的种子,许多小嘴鸟在干旱中死亡,大嘴鸟生存和繁殖(见图),在两年内,小嘴鸟的平均大小增加,自然选择的演变也随之发生。

    Graphs comparing the beak sizes of Galápagos finches in 1976 and 1978, showing evolutionary change.
    Evolution of Beak Size in Galápagos Finches. The top graph shows the beak sizes of the entire finch population studied by the Grants in 1976. The bottom graph shows the beak sizes of the survivors in 1978. In just 2 years, beak size increased.

     

     

     

     

    Check your understanding!
    ::检查你的理解!

     

     

     

    Summary
    ::摘要

    • Biogeography is the study of how and why plants and animals live where they do. It also provides evidence for evolution.
      ::生物地理学是研究植物和动物如何和为什么居住在它们居住的地方,也为进化提供了证据。
    • On island chains, such as the Galápagos, one species may evolve into many new species to fill available niches. This is called adaptive radiation.
      ::在加拉帕戈斯岛等岛屿链上,一种物种可能演变成许多新的物种,以填补现有位置。 这称为适应性辐射。

    Review
    ::回顾

    1. Define biogeography.
      ::界定生物地理学。
    2. Describe an example of island biogeography that provides evidence of evolution.
      ::描述一个岛屿生物地理学的例子,它提供了演变的证据。
    3. Describe the effects of the drought on the Galápagos Islands observed by the Grants.
      ::说明赠款所观察的干旱对加拉帕戈斯群岛的影响。