6.8 后先天先天通过中索zoic时代的演变
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Dinosaur Attack!
::恐龙攻击!Why do children love dinosaurs ? Whether it's Barney the friendly, purple dinosaur or this scary, life-sized Tyranosaurus rex model at a theme park, dinosaurs and children seem to go together. Many people think of dinosaurs as a very ancient life form, but in reality, dinosaurs evolved quite late in the long on our planet. In fact, nearly 80 percent of Earth’s history passed before any type of multicellular life evolved, let alone life with as many as the giant T. rex . Why did evolve? What led up to this major step in the ? To put the evolution of multicellularity in context, it's important to know what was happening on planet Earth during this part of its history, the late Precambrian.
::孩子们为什么喜欢恐龙?是Barney这个友好的、紫色的恐龙还是这个可怕的、生命规模的泰拉诺龙 Rex模型在主题公园、恐龙和孩子之间似乎相互交织。许多人认为恐龙是一种非常古老的生命形式,但实际上,恐龙在我们这个星球上发展得相当晚。事实上,近80%的地球历史在任何类型的多细胞生命进化之前就已经过去了,更不用提巨型T.rex了。为什么演变了?为什么导致了这个重大步骤呢?把多细胞的进化放在这个背景中,重要的是要知道地球在其历史的这一部分,即已故的普雷坎布里安(Precambrian)中发生了什么。Late Precambrian
::迟到的百卡布里亚语NameThe late Precambrian is the time in Earth's history from about two billion to half a billion years ago. During this long span of time, Earth experienced many dramatic geologic and climatic changes.
::已故的Precambrian是地球历史上大约20亿到5亿年前的时代。 在这漫长的时间内,地球经历了许多巨大的地质和气候变化。-
Continents drifted.
They collided to form a gigantic supercontinent, and then broke up again and moved apart. Continental drift changed climates worldwide, and caused intense volcanic activity.
::大陆漂移。它们相撞形成一个巨大的超大陆,然后又再次解体,又四分五裂。 大陆漂移改变了全世界的气候,并引发了强烈的火山活动。 -
Carbon dioxide levels in the
atmosphere
rose and fell.
This was due to volcanic activity and other factors. When carbon dioxide levels were high, they created a
. More heat was trapped on Earth’s surface, and the
climate
became warmer. When the levels were low, less heat was trapped, and the planet cooled. Several times, cooling was severe enough to plunge Earth into an ice age. One ice age was so cold that snow and ice completely covered the planet, as depicted in the image
.
::大气中的二氧化碳水平上升和下降。这是因为火山活动和其他因素。当二氧化碳水平高时,它们创造了一个 。更多的热被困在地球表面,气候变暖了。当温度低时,热量被困,而地球被冷却了。有几次,冷却的强度足以使地球陷入冰河时代。一个冰河时代是如此寒冷,雪和冰雪完全覆盖了地球,正如图像所描述的那样。
Snowball Earth. During the late Precambrian, Earth grew so cold that it was covered with snow and ice. Earth during this ice age has been called “snowball Earth.”
::雪球地球。 在已故的Precambrian期间,地球变得如此寒冷,以至于被冰雪覆盖。 冰雪时代的地球被称为“雪球地球 ” 。Life During the Late Precambrian
::晚前普罗坎布里安的人生The dramatic changes of the late Precambrian had a major impact on Earth’s life forms. Living things that could not adapt died out to be replaced by organisms that evolved new adaptations . These adaptations included , specialization of cells, and multicellularity.
::已故Precambrian的戏剧性变化对地球的生命形式产生了重大影响。 无法适应的活物会死而复生,被进化新适应的有机体所取代。 这些适应包括细胞的专业化和多细胞性。-
Sexual reproduction created much more variety among offspring, increasing the chances that at least
some
of them would survive when the environment changed. It also increased the speed at which evolution could occur.
::性生殖在后代中创造了更多的多样性,增加了他们中至少有一部分在环境变化时生存的机会,也加快了进化的速度。 -
Some cells started to live together in colonies. In some colonies, cells started to specialize in performing different functions. This made the cells more efficient as a colony than as individual cells.
::有些细胞开始在聚居区共同生活。在有些聚居区,细胞开始专门从事不同的功能。这使得细胞作为聚居区比作为单个细胞更有效。 -
By one billion years ago, the first multicellular organisms had evolved. They may have developed from colonies of specialized cells. Their cells were so specialized they could no longer survive as independent cells. However, together they were mighty. They formed an organism that was bigger, more efficient, and able to do much more than any single-celled organism ever could.
::10亿年前,第一种多细胞生物已经进化了。它们可能已经从专门细胞的聚居中发展出来。它们的细胞非常专业化,无法再作为独立细胞生存下去。然而,它们在一起是强大的。 它们形成了一个比任何一个单细胞生物都大、效率更高、能够做更多事情的有机体。
The Precambrian Extinction
::普罗坎布里亚远征At the close of the Precambrian 544 million years ago, a occurred. In a mass extinction , many or even most abruptly die out all over Earth. There have been five mass extinctions in Earth’s history, starting with the Precambrian mass extinction. Earth is currently experiencing a sixth mass extinction .
::在五亿四千四百万年前的Precambrian 5亿四千四百万年前的末期,就发生了。 在一次大规模灭绝中,许多甚至最突然地在地球上死亡。 在地球历史上发生了五次大规模灭绝,首先是Precambrian 大规模灭绝。 目前,地球正经历第六场大规模灭绝。What caused the Precambrian mass extinction? A combination of climatic and geologic events was probably responsible. No matter what the cause, the Precambrian extinction paved the way for a burst of new life during the following .
::是什么原因导致了Precambrian大规模灭绝?气候和地质事件的结合可能是原因之一。 不管原因为何,Precambrian灭绝为以下时期的新生命的爆发铺平了道路:Paleozoic Era
::Paleozoic 时代The Paleozoic Era is literally the era of “old life.” It lasted from 544 to 245 million years ago and is divided into six periods. Major events in each period of the Paleozoic Era are listed in the figure . The era began with a spectacular burst of new life, called the Cambrian explosion . The era ended with the biggest mass extinction the world had ever seen, known as the Permian extinction .
::Paleozoic Eraa是“古老生活”的时代。 它从544万年前的544万年持续到2.45亿年,分为六个时期。 数字中列出了Paleozoic Era每个时期的重大事件。这个时代以惊人的新生命爆发开始,称为Cambrian爆炸。 这个时代以世界有史以来最大的大规模灭绝告终,称为Permian灭绝。The Paleozoic Era includes the six periods described here.
::Paleozoic时代包括这里描述的六个时期。Cambrian Period
::坎布里亚期间Following the Precambrian mass extinction, there was an explosion of new kinds of organisms in the Cambrian Period (544–505 million years ago). Many types of primitive, invertebrate evolved. Many of them were . Small ocean animals called trilobites also became abundant. Both types of organisms are shown in the following figure.
::在Precambrian大规模灭绝之后,坎布里安时期(544-505亿年前 ) ( 544-5.05亿年前 ) , 出现了新型生物的爆炸。 许多原始无脊椎动物进化了。 其中许多是。 被称为三栖动物的小型海洋动物也变得丰富。 下图显示了这两种生物。Two representatives of more than 50 modern animal phyla from the Cambrian explosion are reef-building sponges (left) and early arthropods known as trilobites (right). Both were abundant during the Cambrian and later became extinct; however, the phyla they represent persist to this day.
::坎布里安爆炸中50多个现代动物植物的两名代表是建造珊瑚礁的海绵(左)和早期节肢动物(右),两者在坎布里安期间丰富,后来绝种;然而,它们所代表的植物一直存在到今天。Ordovician Period
::奥尔多维奇时期During the next period, the Ordovician Period (505–440 million years ago), the oceans became filled with invertebrates of many types, and the first evolved. Plants colonized the land for the first time, but animals were still confined to the .
::在下个时期,即奥尔多维奇时期(505—4亿亿年前 ) , 海洋中充斥着多种类型的无脊椎动物,这是第一个进化过程。 植物首次殖民了这片土地,但动物仍然被禁闭在这片土地上。Silurian Period
::锡里时期During the Silurian Period (440–410 million years ago), corals appeared in the oceans, and fish continued to evolve. On land, appeared, like those pictured . With special tissues to circulate water and other materials, vascular plants could grow larger than the earlier, .
::在西卢里安时期(440—4.10亿年前 ) , 珊瑚出现在海洋中,鱼类也在不断进化。 在陆地上,就像那些被描绘的那样出现。 有了特殊的组织来循环水和其他材料,血管植物会比早期大。Cooksonia, a branching vascular plant with sporangia at the tips of each branch. Cooksonia fossils measure just centimeters in height and date back to the Silurian period.
::Cooksonia, 一种支流血管植物, 在每个分支的尖尖处都有螺旋。 Cooksonia 化石在高度上只测量厘米, 并追溯到Silurian 时期 。Devonian Period
::德文期间During the Devonian Period (410–360 million years ago), the first seed plants ( like those pictured ) evolved. Seeds have a protective coat and stored food to help them survive harsh conditions such as dryness. Seed plants eventually became the most common type of land plants. In the oceans, fish with lobe fins evolved. Lobe-finned fish could breathe air when they raised their heads above water. would be necessary for animals to eventually colonize the land.
::在德文时期(410-3.6亿年前 ) , 第一批种子植物(如那些被描绘的植物 ) ( 410-3.6亿年前 ) 发展了。 种子有保护性外套,储存食物帮助他们在干旱等恶劣条件下生存。 种子植物最终成为最常见的陆地植物类型。 在海洋中,带叶鳍的鱼类进化了。 当它们把头抬高到水面上时, 露天鱼可以呼吸空气。 动物最终将这片土地殖民化是必需的。On land, clubmosses, horsetails, and ferns joined primitive seed plants and early trees to form the first forests.
::在陆地上,木头、马尾和野兽加入了原始种子植物和早期树木,形成第一批森林。Carboniferous Period
::碳纤维期During the Carboniferous Period (360–290 million years ago), widespread forests of huge plants left massive deposits of carbon that eventually turned to coal. The first evolved to move out of the water and colonize land, but they had to return to the water to reproduce. Soon after amphibians arose, the first evolved. They were the first animals that could reproduce on dry land.
::在碳纤维时代(360亿到2亿9千万年前 ) , 巨大的植物大面积的森林留下了大量的碳储存,最终变成了煤炭。 第一次进化的是从水中移出殖民土地,但是它们不得不回到水中繁殖。 两栖动物出现后不久,第一次进化。它们是第一批可以在干旱土地上繁殖的动物。Permian Period
::埃尔米亚时期During the Permian Period (290–245 million years ago), all of the major land masses collided to form a single supercontinent, called Pangaea (or Pangea), which is shown on the map . During this period, temperatures were extreme, and the climate was dry. Plants and animals evolved adaptations to dryness, such as waxy leaves or leathery skin to help prevent water loss. The Permian Period ended with another mass extinction.
::在佩尔米亚时期(29-2.45亿年前 ) , 所有主要陆地都相撞形成一个叫做潘盖亚(Pangalea ) 的单一超级大陆。 在地图上可以看到。 在此期间,气温非常高,气候也十分干燥。 植物和动物演变成干燥的适应性,如蜡叶或皮革等,以防止水流失。 佩尔米亚时期以另一次大规模灭绝告终。The supercontinent Pangaea encompassed all of today’s continents in a single land mass. This configuration limited shallow coastal areas (which harbor marine species) and may have contributed to the dramatic event which ended the Permian — the most massive extinction ever recorded.
::超级大陆潘加亚(Pangalea ) 以单一陆地覆盖了当今所有大陆。 这种结构限制了浅沿海地区(海洋物种的栖息地 ) , 并可能促成了结束佩尔米安( Permian)这一史无前例的大规模灭绝的戏剧性事件。In the mass extinction that ended the Permian, the majority of species went extinct. Many hypotheses have been offered to explain why this mass extinction occurred, including huge meteorites striking Earth and enormous volcanoes spewing ashes and gases into the atmosphere. Both could have darkened the skies with dust for many months. This, in turn, would have shut down and also cooled the planet.
::在结束伯尔米安河的大规模灭绝中,大多数物种都灭绝了。 许多假设已经提出来解释大规模灭绝的原因,包括巨大的陨石撞击地球和巨大的火山将灰烬和气体喷入大气层。 两者都可能用尘土使天空暗化了好几个月。 这反过来又会关闭和冷却地球。Despite the great loss of life, there was light at the end of the tunnel. The Permian extinction paved the way for another burst of new life at the start of the following . This included the evolution of the dinosaurs.
::尽管生命遭受巨大损失,但隧道的尽头还是一片光明。波尔米亚的灭绝为在下面开始的新生命又一爆发铺平了道路。这包括恐龙的进化。Mesozoic Era
::中默索索契时代The Mesozoic Era is literally the era of “middle life.” It is also known as the age of dinosaurs. It lasted from 245 to 65 million years ago and is divided into the three periods described in the figure . The Mesozoic began with the supercontinent Pangaea . Then, during the Mesozoic, Pangaea broke up and the continents drifted apart. The movement of continents changed climates. It also caused a great deal of volcanic activity.
::中祖时代实际上就是“中世纪”的时代。 它也被称为恐龙时代,从245万到6500万年前持续到6500万年,分为图中描述的三个时期。中祖时代始于超大陆潘加亚。随后,在中祖时代,潘加亚解体,大陆四分五裂。大陆运动改变了气候。它也引发了大量火山活动。Mass extinctions occurred at the end of the Triassic and Cretaceous Periods of the Mesozoic Era. The first mass extinction paved the way for a dinosaur takeover. In the second mass extinction, the dinosaurs disappeared.
::大规模灭绝发生在梅索索奇时代三亚西奇和白鲸时期的末期,第一次大规模灭绝为恐龙接管铺平了道路。 在第二次大规模灭绝中,恐龙消失了。Mesozoic Era. The Mesozoic Era consists of the three periods described here.
::中司时代 中司时代由这里描述的三个时期组成Triassic Period
::三三assic 期间During the Triassic Period (245–200 million years ago), the earliest dinosaurs evolved from reptiles and began to colonize the land, air, and water. Huge seed and conifers dominated the forests, and modern corals, fish, and evolved. The supercontinent Pangaea started to separate into Laurasia (today’s Northern Hemisphere continents) and Gondwanaland (today’s Southern Hemisphere continents). The Triassic Period ended with a mass extinction.
::在三亚西克时期(2.45亿到2亿年前 ) , 最早的恐龙从爬行动物演变而来,开始将土地、空气和水殖民化。 巨大的种子和锥虫主宰着森林,现代珊瑚、鱼类和进化。 超级大陆潘加亚开始分裂成劳拉西亚(今天的北半球大陆 ) 和贡德瓦纳兰(今天的南半球大陆 ) 。 三亚西奇时期以大规模灭绝告终。Jurassic Period
::侏罗纪时期The Jurassic Period (200–145 million years ago) began after the mass extinction that ended the Triassic Period. This mass extinction allowed dinosaurs to flourish in the Jurassic Period, which is called the golden age of dinosaurs. It opened up many new niches for dinosaurs to exploit. Also during the Jurassic, the earliest evolved from dinosaur ancestors . All of the major groups of mammals evolved, as well, although they were all small in size. Flowering plants appeared for the first time, and new insects evolved to pollinate flowers . The continents continued to move apart, and volcanic activity was especially intense.
::侏罗纪时期(二亿到1.45亿年前)始于结束三亚纪时期的大规模灭绝之后。 这种大规模灭绝让恐龙在被称为恐龙黄金时代的侏罗纪时期蓬勃发展。 它为恐龙开辟了许多新的开发空间。 在侏罗纪时期,最早从恐龙祖先演变而来。 所有主要的哺乳动物群体也都演化了,尽管它们规模都很小。 鲜花植物首次出现,新的昆虫也演变成授粉花。 大陆继续四分五裂,火山活动特别激烈。Cretaceous Period
::白鲸期During the Cretaceous Period (145–65 million years ago), dinosaurs reached their peak in size and distribution. For example, the towering Tyrannosaurus r ex weighed at least seven tons. By the end of the Cretaceous, the continents were close to their present locations. Earth’s overall climate was warm, and even the poles lacked ice. The Cretaceous Period ended with the dramatic extinction of the dinosaurs.
::在白鲸时期(14.5-6.5亿年前 ) , 恐龙的体积和分布达到了顶峰。 比如,巨型暴龙雷克斯的重量至少达到7吨。 在白鲸期结束时,各大洲与目前的位置相近。 地球的总体气候是温暖的,甚至极地也缺乏冰。 白龙期随着恐龙的急剧灭绝而结束。What happened to the dinosaurs? Why did they go extinct at the end of the Cretaceous Period? Some scientists think a comet or asteroid may have collided with Earth, causing skies to darken, photosynthesis to shut down, and the climate to cool. Such a collision was probably at least a contributing factor. Without the dinosaurs, there were many opportunities for new organisms to exploit in the next era, the . Which living things do you think took over after the dinosaurs were gone?
::恐龙到底怎么了?为什么它们会在白鲸期结束时灭绝?有些科学家认为彗星或小行星可能与地球相撞,导致天空暗淡,光合作用关闭,气候冷却。这种碰撞至少是一个促成因素。没有恐龙,在下一个时代,新生物就有很多机会可以被利用。在恐龙消失后,你认为是哪些生物?Feature: Myth vs. Reality
::特征:神话对现实Given the popularity of dinosaurs in fictional media, it's not surprising that there are many myths about them. Here are just a few of the most common dinosaur myths:
::鉴于恐龙在虚构的媒体中很受欢迎,关于它们的许多神话并不奇怪。这里只是几个最常见的恐龙神话:Myth: Dinosaurs are good examples of failure and extinction.
::传说:恐龙是失败和灭绝的好例子。Reality: D inosaurs are actually good examples of biological success and adaptation. They existed on Earth longer than any other land animals (over 150 million years). They also gave rise to birds.
::现实: 恐龙实际上是生物成功和适应的好例子。 它们存在于地球上的时间比任何其他陆地动物都长( 超过1.5亿年 ) 。 它们也产生了鸟类。Myth: Dinosaurs and early humans coexisted.
::传说:恐龙和早期人类共存。Reality: The extinction of the last dinosaurs occurred more than 60 million years before the earliest members of our own genus (Homo) first appeared.
::现实:最后的恐龙灭绝 发生在六千万年前 最早的恐龙成员(霍莫) 首次出现之前Myth: All dinosaurs lived at the same time.
::所有恐龙都同时生活Reality: The span of time between the earliest and latest dinosaur groups was about 65 million years, or at least as long as the span of time between the last of the dinosaurs and modern humans.
::现实:最早的恐龙群和最新的恐龙群之间的时间跨度约为6500万年,或至少与最后的恐龙和现代人类之间的时间跨度一样长。Myth: Mammals arose after the dinosaurs went extinct.
::传说:恐龙灭绝后,哺乳动物出现Reality: Mammals and dinosaurs both first appeared at about the same time, in the late Triassic Period. Mammals diversified greatly, grew larger, and became the dominant land animals after the dinosaurs went extinct.
::现实:哺乳动物和恐龙在后三亚西克时期同时首次出现。 哺乳动物和恐龙在恐龙灭绝后成为占支配地位的陆地动物。Myth: All large reptiles from the prehistoric past were dinosaurs.
::神话:史前古代的所有大型爬行动物 都是恐龙。Reality: Dinosaurs made up less than ten percent of the reptile groups from the Mesozoic Era.
::现实:恐龙在中索佐伊克时代的爬行动物群中只占不到10%。Summary
::摘要-
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. These included sexual reproduction, cell specialization, and multicellularity. The Precambrian ended with a mass extinction, which paved 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。许多生物无法幸存变化并死亡。其他生物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。 Precambrian以大规模灭绝告终,这为Cambrian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.
::中索奇时代是恐龙时代,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。 恐龙在中索索奇时代末期灭绝了。
Review
::回顾1. Describe the geologic and climatic changes that occurred during the late Precambrian.
::1. 描述已故Precambrian期间发生的地质和气候变化。2. What is a mass extinction?
::2. 什么是大规模灭绝?3. Explain the relationship between the Precambrian extinction and the Cambrian explosion.
::3. 解释Precambrian灭绝与Cambrian爆炸之间的关系。4. List several important evolutionary events that occurred during the Paleozoic Era.
::4. 列出在Paleozoic时代发生的若干重要的进化事件。5. Describe how the continents drifted during the Mesozoic Era.
::5. 描述各大陆在中索佐伊克时代是如何漂流的。6. Relate the Permian, Triassic, and Cretaceous mass extinctions to the evolution and extinction of the dinosaurs.
::6. 将Permian、Triassic和白鲸大规模灭绝与恐龙的演变和灭绝联系起来。7. Explain advantages of sexual reproduction and multicellularity.
::7. 解释性生殖和多细胞的优点。8. Arrange the following organisms in order of when they first evolved, from the earliest to the most recent: vascular plants, fish, amphibians, sponges, reptiles.
::8. 将下列生物按照它们最初从最早到最近进化的顺序排列:血管植物、鱼类、两栖动物、海绵、爬行动物。9. Dinosaurs evolved most directly from:
::9. 恐龙最直接的演变来自:a. invertebrates
::a. 无脊椎动物b. amphibians
::b. 两栖c. reptiles
::c. 爬行动物d. trilobites
::d.三叶10. Mammals evolved during the:
::10. 哺乳动物在以下时期演变:a. Cretaceous Period
::a. 白鲸期b. Late Triassic Period
::b. Triassic 后期时期c. Mesozoic Era
::c. 中多变性时代ad. B and C
::d. B和C11. True or False: We are currently experiencing a mass extinction.
::11. 真实或假:我们目前正经历大规模灭绝。12. True or False: When carbon dioxide levels in the atmosphere are high, the climate becomes colder, which can cause an ice age.
::12. 真实或假:当大气二氧化碳水平高时,气候变冷,可能导致冰河时代。13. What is the evolutionary significance of lobe-finned fish?
::13. 白鳍鱼类的进化意义是什么?14. What is an advantage that reptiles have over amphibians that allowed them to flourish in dry areas?
::14. 爬行动物对两栖动物有什么好处,使他们能在干旱地区繁衍昌盛?Explore More
::探索更多Dinosaurs evolved over millions of years into the modern birds we see today. How did such large creatures become so small? Find out here:
::几百万年来,恐龙演变成现代鸟类。这些大型生物是如何变小的?Ever wonder how life transitioned to land? Check this out:
::想知道生活是如何向陆地过渡的吗? -
Continents drifted.
They collided to form a gigantic supercontinent, and then broke up again and moved apart. Continental drift changed climates worldwide, and caused intense volcanic activity.
