Dinosaurs
美音、自然拼读、分级阅读与词汇复习
Finding Fossils How do we know dinosaurs lived on Earth?
寻找化石 我们怎么知道恐龙生活在地球上?
Scientists called paleontologists discover fossils in rocks all over the world.
科学家称古生物学家在世界各地的岩石中发现了化石.
Studying fossils helps them learn about dinosaurs, including what they looked like, where they lived, and what they ate.
研究化石有助于他们了解恐龙,包括它们的外形,住在哪里,吃什么.
Bone fossils start to form after the death of a dinosaur.
骨化石在恐龙死后开始形成.
Over time, layers of mud, sand, or dirt cover the remains of the dead dinosaur.
随着时间的推移,多层泥沙或泥土覆盖了已死恐龙的遗骸.
Once covered, the bones are protected from scavengers as well as rain and other weather conditions.
一旦被覆盖,骨骼就受到保护,免受取腐动物以及雨水和其他天气条件的影响。
They remain underground until they are discovered millions of years later.
它们一直处于地下,直到数百万年后被发现.
Sometimes the dinosaur’s bones have turned to stone.
有时恐龙的骨头会变成石头
In other cases, hard mud surrounds the bones, but the bones have actually decayed.
在其他情况下,硬泥会包围骨骼,但骨骼实际上已经腐烂.
Paleontologists can study the spaces where the bones used to be.
古生物学家可以研究骨头曾经存在的空间.
They can then recreate the bones based on the shapes of the spaces left behind.
然后他们可以根据所剩空间的形状来再生出骨头.
Paleontologists have found many different types of dinosaur fossils, including bones, footprints, teeth, nests, and eggs.
古生物学家已经发现了许多不同类型的恐龙化石,包括骨骼,脚印,牙齿,巢穴和卵.
These paleontologists are excavating, or carefully digging, bone fossils out of the ground.
这些古生物学家正在从地上挖掘出或仔细地挖掘出骨头化石.
After recording information about them, the paleontologists will wrap the fossils to keep them safe.
古生物学家在记录了有关他们的信息后,会将化石包裹起来,保证它们的安全.
Then they will take the fossils to a museum, where they will examine them.
然后他们把化石带到一个博物馆,在那里检查.
Paleontologists will study different features of the fossils, such as their shape and color.
古生物学家会研究化石的不同特征,如外形和颜色等.
They’ll consider where the fossils were discovered and how deep underground they were discovered.
他们将考虑化石在哪里被发现,
By comparing their finds to other fossils, paleontologists try to figure out what type of dinosaur they have discovered.
通过将发现与其他化石进行比较,古生物学家试图找出他们发现的恐龙种类.
Sometimes they can fit bone fossils together to form a complete skeleton.
有时它们可以把骨化石合在一起形成完整的骨架.
However, it’s rare that a complete skeleton is found together or can be put together over time.
然而,一个完整的骨架很少被一起找到,或者可以随着时间的推移被组合起来.
Most dinosaurs had hundreds of bones, so it is difficult to find all of them.
多数恐龙有上百个骨头,所以很难找到它们的全部.
Scientists use other dinosaur skeletons as models for the ones they are trying to put together.
科学家们用其他恐龙骨架做模型 来作为他们试图组合的模型。
Learning from Fossils Paleontologists use many other types of animal skeletons to help them learn about dinosaur skeletons.
从化石古生物学家那里学习,利用了许多其他类型的动物骨架来帮助他们学习恐龙骨架.
Although dinosaurs are extinct, many animals alive today share certain characteristics with them.
虽然恐龙已经灭绝,但今天许多活生生的动物都与它们有着一定的特征.
Some dinosaur bones may be bigger than those of animals alive today.
有些恐龙骨可能比今天活生生的动物大.
However, the shapes of certain bones and the way their bones fit together are sometimes related.
然而,某些骨骼的形状和它们的骨骼相接的方式有时是相通的.
Many different types of dinosaurs once roamed Earth.
许多不同类型的恐龙曾经在地球漫游.
Paleontologists study fossils to learn how dinosaurs moved around.
古生物学家研究化石,以了解恐龙如何四处移动.
Some dinosaurs walked on two or four legs, and some used wings to fly.
有的恐龙以两四条腿行走,有的用翅膀来飞行.
As dinosaurs moved around Earth, they left tracks behind in mud.
当恐龙环绕地球移动时,它们留下了泥地的痕迹.
Paleontologists study fossil footprints to learn how fast or slow dinosaurs moved.
古生物学家研究化石足迹,以了解恐龙移动多快或慢.
Footprints also give paleontologists clues about how big or small the dinosaur leaving the tracks might have been.
足迹还给出了古生物学家的线索,说明出轨的恐龙可能有多大或多大.
Paleontologists study fossil teeth to learn about what dinosaurs ate.
古生物学家研究化石牙齿,以了解恐龙吃什么.
Many dinosaurs grew new teeth to replace those they had worn down or lost.
许多恐龙长出新牙来取而代之的是已经磨损或丢失的.
Carnivores often had razor-sharp teeth that helped them cut through meat.
肉食动物往往有剃须刀尖的牙齿,帮助他们切出肉来.
Some of their teeth were even strong enough to crush bone.
他们的一些牙齿甚至足够坚固来压碎骨头.
Herbivores usually had sharp beaks that they used to gather plants.
草食动物通常有尖喙,用来采集植物.
Some also had flat teeth to grind tougher plant materials, while others had sharper teeth for chopping their food.
有些还用平齿来磨取更坚硬的植物材料,而另一些则用更尖的牙齿来切取食物.
Still other dinosaurs had both flat and sharp teeth.
还有其它恐龙有平和尖的牙齿
Paleontologists learn about dinosaur babies from fossil nests and eggs.
古生物学家从化石巢和卵上了解了恐龙宝宝.
Dinosaur eggs came in many different shapes and sizes, including small round eggs and large oval eggs.
恐龙蛋有多种不同的形状和大小,包括小圆卵和大椭圆卵.
Some dinosaurs laid over twenty eggs at a time, while others laid only a few eggs.
有的恐龙一次产下20个蛋,有的只产出几个蛋.
Similar to birds, some dinosaurs may have sat on their nests until their eggs hatched.
与鸟类类似,有的恐龙可能一直坐在巢上直到卵孵出.
Paleontologists find fossils of plants, fish, insects, and other animals in the same rocks as dinosaur fossils.
古生物学家在与恐龙化石相同的岩石上发现了植物,鱼类,昆虫等动物的化石.
These fossils help them learn what Earth was like when dinosaurs lived here.
这些化石有助于他们了解恐龙住在这里时地球是什么样.
More examples of these other types of fossils have been discovered than dinosaur fossils.
比起恐龙化石,这些其它类型的化石被发现的例子更多.
These fossils are usually smaller and more complete than dinosaur fossils.
这些化石通常比恐龙化石更小更完整.
Therefore, paleontologists can more easily tell the age of these other fossils.
因此,古生物学家可以更容易地分辨出这些其他化石的年代.
They are then able to use the other fossils to estimate the age of dinosaur fossils.
然后,它们能够利用其他化石来估计出恐龙化石的年代.
How Long Ago?
有多长的Ago?
Paleontologists can perform tests to find out the age of fossils.
古生物学家可以进行测试来发现化石的年代.
Older fossils are found deeper in the ground than newer fossils.
更古老的化石在地上被发现比更新的化石更深.
More recent fossils are found in rocks closer to the surface.
更近的化石发现于更接近地表的岩石上.
The oldest dinosaurs lived around 230 million years ago.
最早的恐龙生活在2.3亿年前左右.
These dinosaurs were only the size of large dogs.
这些恐龙只是大狗的体型.
It wasn’t until around 145 million years ago that giant dinosaurs roamed on Earth.
直到1.45亿年前,
Paleontologists have many different ideas to explain how dinosaurs disappeared around 65 million years ago.
古生物学家有许多不同的想法来解释恐龙在大约6500万年前是如何消失的.
Studying dinosaur fossils helps paleontologists look for clues to understand what happened.
研究恐龙化石有助于古生物学家寻找线索来了解发生了什么.