6.9 基因组时代的演变
Section outline
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Big Body, Little Brain
::大身体,小大脑If you could travel back in time about 50 or 60 million years, you might see like those pictured here. Called coryphodons, they were members of the world's first group of large browsing mammals . They migrated across what is now northern North America. Although smaller than many mammals would eventually become, they were larger than most other animals that lived during the same time. They probably weighed at least half a ton when fully grown, but their brains were very small. In fact, they had one of the smallest brains for any mammal of their size, living or extinct. Long gone now, corpyhodons are just one of a plethora of mammals that evolved during the most recent geologic era, the Cenozoic.
::如果你可以回到大约五、六千万年的时间里, 你可能会看到像这里所描绘的那样。 被称为 Coryphondon, 他们是世界上第一组大型浏览哺乳动物。 它们迁移到北美北部。 虽然它们最终会变得小于许多哺乳动物, 但是它们比大多数同时生存的动物还要大。 当它们完全生长的时候, 它们可能至少体重半吨, 但是它们的大脑很小。 事实上, 它们拥有一个最小的大脑, 任何哺乳动物的大小, 生存或灭绝。 很久以前, 它们只是最近地质学时代, 即 遗传学时代, 进化的众多哺乳动物之一。Overview of the Cenozoic Era
::Cenozocic时代概览The Cenozoic Era literally means the era of “modern life.” It began about 65 million years ago and continues to the present day. Early in the Cenozoic Era, Earth was dominated by relatively small animals, including mammals, , , and . As the Cenozoic progressed, first birds, and then mammals greatly diversified, taking advantage of the extinction of the dinosaurs that occurred at the end of the preceding . Some flightless birds were very large and formidable predators at the top of their . Mammals came to occupy almost every available niche both in and on land. Some mammals also evolved very large sizes, greater than most of today's land mammals. The success of mammals during the Cenozoic is the reason that this era is often referred to as "the age of mammals."
::Cenozoic Eraa字面意思是“现代生命”的时代。它始于大约6500万年前,并一直持续到今天。在Cenozoic Eraa早期,地球由相对较小的动物主宰,包括哺乳动物,还有。随着Cenozoic的进化,先是鸟类,然后是哺乳动物,利用前一个时代末期发生的恐龙灭绝,使哺乳动物多样化。有些没有飞行的鸟类在它们的顶端是非常庞大和可怕的捕食者。哺乳动物几乎占据了陆地上和陆地上的每一个位置。有些哺乳动物也发展了非常大的规模,比当今大多数陆地哺乳动物还要大。在Cenozoozoic期间哺乳动物的成功是这个时代经常被称为“哺乳动物时代”的原因。Geologically, the Cenozoic is the era when the continents finally moved into their current positions. Earth's climate was warm and wet at the start of the Cenozoic, but it became cooler and drier throughout most of the rest of the era. This cooling trend culminated in an ice age that began about three million years ago and continued to about 12 thousand years ago. As Earth grew drier, forests shrank and were replaced by grasslands, and eventually deserts formed. All of these changes had a huge impact on the evolution of living things during the Cenozoic Era.
::从地质学上讲,这个时代是各大洲最终进入目前位置的时代。 地球的气候在开始时是温暖和湿润的,但在大部分时间里却变得更冷和干燥。 这一冷却趋势在大约300万年前开始的冰河时代中达到顶峰,持续到大约12000年前。随着地球干旱,森林萎缩,被草原所取代,最终形成沙漠。 所有这些变化都对塞诺祖奇时代生物的演变产生了巨大影响。Subdivisions of the Cenozoic Era
::切诺zocic时代分区The Cenozoic Era was traditionally divided into two periods, the Tertiary Period (65-1.8 million years ago) and the Quaternary Period (1.8 million years ago to the present). Some of the major climatic and evolutionary changes of the two periods are listed in the figure .
::Cenozoic Eraa传统上分为两个时期:第三周期(6 500万至180万年前)和第四周期(180万年前至今)。Cenozoic Era. One way of dividing the Cenozoic Era is into the two periods described here. Today, the Cenozoic Era is more commonly divided into three periods. The Tertiary Period has largely been replaced by two periods called the Paleogene and Neogene Periods. The Quaternary Period is sometimes called the Anthropogene Period for the importance of human evolution and human actions during this period ( anthropo- means "human") . The three periods of the Cenozoic Era are further subdivided into seven epochs, as outlined in the detailed and described in the text that follows. Division of the Cenozoic Era into epochs helps paleontologists better organize and group the many significant events that occurred during this comparatively short interval of time. There is also more detailed knowledge of this era than any other.
::今天,Cenozoic Eraa更经常地分为三个时期,第三时期基本上被称为Paleogene和Neogene时期的两个时期所取代,第四时期有时被称为人类人文时期,在这个时期人类进化和人类行动的重要性(人类-人类-人类-人类-人类-人类-人类-人类-),后三个时期又进一步细分为七个时代,如下文详细和描述的那样。将Cenozoic Era分成一个时代,有助于古生物学家更好地组织和分组在这一相对较短的时期内发生的许多重大事件。对这个时代的了解也比任何其他时期都详细。This version of the geologic time scale shows the periods and epochs of the Cenozoic Era. Note that the heading MA in the right-most column refers to millions of years ago. Paleogene Period
::白种植物时期The Paleogene Period spans the time from the extinction of the dinosaurs about 65 million years ago to the start of the Neogene Period some 23 million years ago. It includes three epochs: the Paleocene, Eocene, and Oligocene Epochs.
::从大约6,500万年前恐龙灭绝到大约2,300万年前的Neogene时期的开始,这段时期包括三个时代:帕莱奥克人、欧洲人和奥利戈人。Paleocene Epoch
::帕莱辛乙烷EpochThe Paleocene Epoch lasted from about 65 million to 55 million years ago. This epoch featured a temporary warming trend, with thick forests eventually reaching the poles. The continents were beginning to take their modern shapes, although all of them were still separated from each other. W hat would become North and South America, for example, had not yet been connected by the Isthmus of Panama. There were many mammals during the Paleocene, but all of them were still quite small. The earliest (the order of mammals to which humans belong) appeared around 50 to 55 million years ago, toward the end of the Paleocene Epoch.
::帕莱奥切埃波奇河从大约6 500万年前的6 500万年延续到5 500万年前。这个时代呈现了暂时的变暖趋势,茂密的森林最终会到达极地。各大洲开始呈现现代的形态,尽管它们仍然相互隔绝。例如,成为北美和南美洲的东西还没有被巴拿马的地峡连接起来。在帕莱奥切内河中有许多哺乳动物,但它们都仍然很小。最早的(人类所属的哺乳动物的顺序)在五千万到五千五百万年前,直到帕莱奥切埃波奇河的尽头。Eocene Epoch
::Eocene Epoch( 乙苯乙酸)The Eocene Epoch covered the period from about 55 million to 33 million years ago. Earth's climate was still warm during the early Eocene, but by the mid-Eocene, changing ocean currents and other factors started a worldwide cooling and drying trend. The changing climate caused forests to shrink. By the late Eocene, grasses had evolved and grasslands had started to replace the forests. At first, birds were the dominant animals, some of them extremely large — but they were gradually replaced by mammals as the dominant fauna.
::地球的气候在早期的环球气候中仍然很温暖,但到中期,变化中的洋流和其他因素开始在全世界形成一种冷却和干燥的趋势,气候变化导致森林萎缩,随着晚期的环球气候,草已经演变,草地开始取代森林,首先,鸟类是主要动物,其中一些非常大,但是它们逐渐被哺乳动物取代,成为主要动物。Oligocene Epoch
::Oligocene Epoch(欧洲)The Oligocene Epoch began about 33 million years ago and continued until 23 million years ago. Earth's climate continued to become cooler and drier, and grasslands kept expanding. Changes in climate and vegetation led to the evolution of new of mammals, including the first elephants. Many new species of plants also evolved during this epoch, such as evergreen trees. Some mammals grew very large, and the largest land mammal that ever lived — the now extinct Paraceratherium — evolved during the Oligocene. The illustration shows how large this mammal was compared with its modern rhinoceros relatives and an average-sized adult man.
::Oligocene Epoch于大约3 300万年前开始,一直持续到2 300万年前,地球的气候继续变冷和干燥,草地不断扩大,气候和植被的变化导致哺乳动物(包括第一头大象)的进化,许多新的植物种类在这个时代也发展,例如长青树,一些哺乳动物生长很大,在奥利戈西内地区,哺乳动物——现在已经绝种的麻痹动物——发展成为有史以来最大的哺乳动物,这说明哺乳动物与现代犀牛亲戚和普通成年男子相比有多大。Paraceratherium is the largest known mammal to have ever lived on Earth. Neogene Period
::神经神经周期The Neogene Period spanned the time from 23 million to about 2.6 million years ago. It is further subdivided into two epochs: the Miocene and Pliocene Epochs.
::Neogene时期的时间从2 300万年到260万年前的大约260万年不等,它又进一步细分为两个时代:米奥辛和普利奥辛埃波奇。Miocene Epoch
::甲苯乙酸The Miocene Epoch began 23 million years ago and continued to five million years ago. The climate continued to grow cooler and drier throughout this epoch. Forests kept shrinking, and grasslands spread over a large portion of the world. Grazing mammals became increasingly important as the grasslands expanded. You can see how some of these mammals looked in the artist's rendition . Primates called apes also evolved during this epoch, and they diversified into many different species. Many new types of plants evolved as well, including most modern seed plants.
::2300万年前开始并持续到500万年前。整个这个时代的气候继续变冷和变干。森林不断缩小,草原遍布世界大部分地区。放牧哺乳动物随着草原的扩大变得日益重要。你可以看到这些哺乳动物在艺术家的移位中是如何看待这些哺乳动物的。在这个时代,被称为猿的原始动物也进化了,它们多样化成许多不同的物种。许多新型植物也进化了,包括大多数现代种子植物。This picture shows some of the many mammals that dominated the land during the Miocene Epoch. Pliocene Epoch
::Pliocene Epoch 光电The Pliocene Epoch covered the time period from five million to about 2.6 million years ago. The climate grew even dryer and cooler, and continued desiccation led to the Mediterranean Sea drying up for several million years. The drying climate also led to grasslands, called savannas, which are continuing to spread in tropical areas around the world. The climate also brought deserts to East Asia. Close human ancestors called A ustralopithecines first appeared in African savannas during the Pliocene (you can read about Australopithecines in the concept E arly Hominin Evolution ) . In the New World, the Isthmus of Panama formed, allowing animals to migrate between North and South America. Earth's continents and seas took on their present shapes and positions.
::Pliocene Epoch 覆盖了500万到大约260万年前的时期。气候甚至变干和变冷,持续干燥导致地中海干涸了数百万年。干燥的气候还导致草原,称为稀树草原,继续在世界各地热带地区蔓延。气候还把沙漠带到东亚。紧邻的人类祖先Australoptithecines在普利奥肯期间首次出现在非洲草原上(你可以读到早期霍明进化概念中的Australopithelinesines ) 。在新世界,巴拿马的地峡形成,允许动物在南北美洲之间迁徙。地球的大陆和海洋以目前的形式和位置出现。Quaternary Period
::四、四、四、四周期The Quaternary (or Anthropogene) Period began about 2.6 million years ago, and continues today. It is subdivided into two epochs: the Pleistocene and Holocene Epochs.
::四代(或人种化)时期始于大约260万年前,并一直持续到今天。 它被细分为两个时代:白球和环球。Pleistocene Epoch
::帕列斯诺克埃波克The Pleisotcene Epoch spans the period from about 2.6 million to 12 thousand years ago. Climate changes continued during this epoch, with the cooling trend that began in the middle of the Miocene Epoch culminating in the most recent ice age. There were at least four separate glaciation periods during this ice age, marked by the advance of glaciers almost as far south as the current locations of Chicago and New York City. During the intervening interglacial periods, temperatures were somewhat warmer, and the glaciers retreated. Africa continued to become drier during the Pleistocene, leading to the formation of African deserts, including the Sahara and Kalahari. The Pleistocene was the epoch of megafauna, or very large mammals, which included mammoths, giant ground sloths, giant beavers, and saber-toothed cats, like the ones pictured . However, most of the megafauna were wiped out in a that began toward the end of the Pleistocene.
::Pleisotcene Epoch在大约260万年前到12 000年前的这段时期。在这个时代,气候变化仍在继续,在米奥切埃波奇中部开始的冷却趋势达到最近的冰河时代。在这一冰河时期,至少有四个不同的冰川疏松期,冰川向南发展到芝加哥和纽约市的目前地点,冰川向南近至芝加哥和纽约市的目前地点。在中间的冰川间歇期间,气温比较暖和,冰川退缩。非洲在普里斯特内继续变得干燥,导致非洲沙漠的形成,包括撒哈拉和卡拉哈里。巨型动物是巨型动物,或非常大的哺乳动物,包括哺乳动物、巨型地槽、巨型海狸和大齿猫,如所描绘的一样。然而,大多数巨型动物在普利斯特克内末端开始灭绝。Saber-toothed cats like these were important predators during the Pleistocene Epoch. The Pleistocene is of special interest to us because this is when our own genus , Homo, and our own species, Homo sapiens , evolved. on megafauna by human hunters may have contributed to their demise near the end of the Pleistocene. How our genus and then our species evolved and later spread throughout the world during the Pleistocene Epoch is described in detail in the chapter Human Evolution.
::我们特别感兴趣的是Pleistocene(Pleistocene) , 因为这是当我们自己的基因,同族, 和我们自己的物种,同族,同族,进化成人的时候。人类猎人在巨型动物身上的进化过程, 可能会在Pleistocene的末端促成巨型动物的消亡。人类进化的一章详细描述了我们的基因,然后我们的物种是如何进化的,后来在Pleistocene Epoch(Pleistocene Epoch)期间在全世界扩散的。Holocene Epoch
::Epoch 聚聚苯乙烯The Holocene Epoch began about 12 thousand years ago and continues to the present. This is the epoch during which human beings became ascendant and within which all of recorded human history occurred. Starting around ten thousand years ago, modern humans invented in the Middle East, and somewhat later, agriculture was invented independently in the New World. The invention of writing and the first cities date back to at least three thousand years ago, both in the Middle East. The mass extinction that began near the end of the Pleistocene continued in the Holocene, most likely because of human activities. The rate of extinction of species, mainly due to loss of habitat , has increased dramatically over the past few centuries. Hundreds of species are known to have gone extinct just since the Industrial Revolution, which began in the mid-1700s. Referred to as the sixth mass extinction , this extinction event is still going on today.
::约12 000年前开始并延续到现在。这就是人类在那个时代中升起,并在这个时代中发生了所有人类历史记录。从大约1 000年前开始,现代人类在中东发明,后来又在新世界中独立发明农业。书写的发明和第一个城市至少可以追溯到3 000年前,这两个城市都在中东。普里斯特涅的末期开始的大规模灭绝在全新世界中持续,最可能是因为人类的活动。物种的灭绝速度,主要是由于生境的丧失,在过去几个世纪中急剧上升。自工业革命(始于1700年代中期)开始以来,数百种物种已经灭绝。这一灭绝事件被称为第六大灭绝,今天仍在继续。Summary
::摘要-
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: the Paleogene, Neogene, and Quaternary (or Anthropogene) Periods.
::今天,Cenozoic Era一般分为三个时期:Palegene、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。 -
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。
Review
::回顾1. Summarize the geologic and climatic changes that occurred during the Cenozoic Era.
::1. 概述在Cenozoic时代发生的地质和气候变化。2. Why is the Cenozoic Era called "the age of mammals?"
::2. 为什么Cenozoic Eraa被称为“哺乳动物的年龄?”3. Explain how the Cenozoic Era is subdivided. Include time spans for the major divisions.
::3. 解释如何对 " 代谢时代 " 进行细分,包括主要分区的时间间隔。4. Why is the Quaternary Period also called the Anthropogene Period?
::4. 为什么四年度期间也称为人类基因期?5. What is the sixth mass extinction? What is its major cause?
::5. 第六次大规模灭绝是什么?其主要原因是什么?6. Name our current era, period, and epoch.
::6. 指出我们当前的时代、时期和时代。7. True or False: Mammals evolved for the first time during the Cenozoic Era.
::7. 真实或假:哺乳动物在Cenozoic时代首次进化。8. True or False: The sixth mass extinction began with the Industrial Revolution.
::8. 真实或假:第六次大规模灭绝始于工业革命。9. True or False: All modern plants evolved prior to the Cenozoic Era.
::9. 真实或假的:所有现代植物都是在 " 基因时代 " 之前进化的。10. During which epoch did primates evolve?
::10. 灵长类在哪个时代演变?a. Paleocene
::a. 帕丁基b. Eocene
::b. 环乙烷c. Oligocene
::c.d. Miocene
::d. 弥丁烷11. During which epoch did apes evolve?
::11. 在哪个时代,猿类演变了?a. Pliocene
::a. 钚b. Eocene
::b. 环乙烷c. Oligocene
::c.d. Miocene
::d. 弥丁烷12. At various times in Earth’s history, land masses that had once been separate became connected, such as during the ice ages of the Cenozoic, which resulted in land bridges between continents. How do you think this may have impacted life on Earth?
::12. 在地球历史上的不同时期,曾经分开的陆地群变得相互连接,例如在Cenozoic的冰河时代,这导致了各大陆之间的陆地桥梁,你认为这会如何影响地球上的生命?13. Grasslands expanded during the Cenozoic. How do you think this could have influenced the evolution of mammals in these regions?
::13. 基因组学期间扩大的草原,你认为这会如何影响这些地区哺乳动物的演变?14. Modern agriculture was developed by humans about...
::14. 现代农业是由人类开发的...a. two thousand years ago
::a. 两千年前b. six thousand years ago
::b. 六千年前c. ten thousand years ago
::c. 一万年前d. 12 thousand years ago
::d. 12 000年前Explore More
::探索更多To learn more about where the first Americans came from, check out this video:
::更多了解第一批美国人来自何方, -
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.
