少儿英语 恐龙及其灭绝 Dinosaursandextinction

1、Dinosaurs and ExtinctionBy Ashby MorellClip Art and Sounds - Microsoft Office 2007, unless noted otherwiseCorresponding State Standards GLE 0107.5.2 Recognize that some organisms which formerly lived are no longer found on earth. 0107.5.3 Sort pictures or illustrations of animals into groups that ar

2、e extinct and those that still exist and offer possible explanations for extinction.Dinosaurs lived long ago before people existed.Dinosaurs, along with many other types of animals, are now extinct. Extinct means there are no longer any of this type of animal alive.Other animals, besides dinosaurs,

3、have become extinct.The saber tooth tiger, wooly mammoth, and flightless dodo bird are all extinct animals.The saber tooth picture is from Free Gifts & Animations at www.fg-, the wooly mammoth is was drawn by Benjamin Waterhouse Hawkins from http:/publicdomainclip-art (copyright expired) and the

4、 dodo bird from Dodo. 22 April 2008. HowStuffW. 08 June 2009.Animals become extinct for different reasons. In some cases, animals are hunted until they become extinct.Sometimes animals are brought to new places. These animals will hunt an animal native to the land until it is extinct.Dinosaurs have

5、been extinct for millions of years.Scientist have different theories on why dinosaurs are extinct. A theory is an idea based on scientific evidence.Some scientists believe dinosaur extinction happened because an asteroid hit the earth, causing most plants to die. The herbivores, or plant eating dino

6、saurs starved without any food.Another theory of extinction is that asteroids caused massive fires that killed most plant life and the dinosaurs. Other scientists believe something drastic happened to make earths global temperatures very cold. With temperatures so cold, dinosaurs either froze to dea

7、th, or all plant life died. Herbivores then had nothing to eat.Another theory of extinction is that many volcanic eruptions occurred.Some scientists believe all the dinosaurs died from disease.Why did dinosaurs become extinct?Scientists will continue to study fossils and the earth to try and find the answer to this question.No one really knows for sure why dinosaurs became extinct.Lets see how much you remember!Is this