恐龙简介恐龙是出现于二亿四千五百万年前，并繁荣于六千五百万年前结束的中生代爬行动物。
或为恐龙和与它同一时代的蛇颈龙、翼龙等的模糊总称。
恐龙在在6500万年前白垩纪结束的时候突然全部消失，成为地球生物进化史上的一个谜，这个谜至今仍无人能解。
地球过去的生物，均被记录在化石之中。
中生代的地层中，即曾发现许多恐龙的化石。
其中可以见到大量或呈现各式各样形状的骨骼。
但是，在紧接着的新生代地层中，却完全看不到恐龙的化石。
由此推知恐龙在中生代时一起灭绝了。
恐龙种类多，体形和习性相差也大。
其中个子大的，可以有几十头大象加起来那么大；小的，却跟一只鸡差不多。
就食性来说，有温顺的草食者和凶暴的肉食者，还有荤素都吃的杂食性恐龙。
Dinosaur ProfileDinosaurs appeared in two hundred forty-five million years ago, and prosperity at the end of the Mesozoic reptiles 65 million years ago. , Or dinosaurs, and with it the same era plesiosaurs, pterosaurs and other fuzzy generic term. Dinosaurs in the Cretaceous period ended 65 million years ago when all of a sudden disappeared, a mystery of the evolutionary history of life on Earth, is still without a person who can answer this mystery. Creatures of the Earth in the past, are being recorded in the fossil. Mesozoic strata, that many dinosaur fossils have been found. Where you can see the bones of large or presents a wide range of shapes. However, in the following Cenozoic strata, but completely see less than the fossils of dinosaurs. We concluded that with the extinction of the dinosaurs in the Mesozoic.Many kinds of dinosaurs, body shape and habits also big difference. Large sub then dozens of elephants together; small, but with almost a chicken. Docile herbivorous, feeding habits,The meat eaters and violent, as well as meat and vegetables to eat omnivorous dinosaur.Dinosaurs,one of the most successful groups of animals (in terms of longevity) that have ever lived,evolved into many diverse sizes and shapes,with many equally diverse modes of living.The term "Dinosauria" was invented by Sir Richard Owen in 1842 to describe these "fearfully great reptiles," specifically Megalosaurus,Iguanodon,and Hylaeosaurus,the only three dinosaurs known at the time.The creatures that we normally think of as dinosaurs lived during the Mesozoic Era,from late in the Triassic period (about 225 million years ago) until the end of the Cretaceous (about 65 million years ago).But we now know that they actually live on today as the birds.Some things to keep in mind about dinosaurs:•Not everything big and dead is a dinosaur.All too often,books written (or movies made) for a popular audience include animals such as mammoths,mastodons,pterosaurs,plesiosaurs,ichthyosaurs,and the sail-backed Dimetrodon.Dinosaurs are a specific subgroup of the archosaurs,a group that also includes crocodiles,pterosaurs,and birds.although pterosaurs are close relations,they are not true dinosaurs.Even more distantly related to dinosaurs are the marine reptiles,which include the plesiosaurs and ichthyosaurs.Mammoths and mastodons are mammals and did not appear until many millions of years after the close of the Cretaceous period.Dimetrodon is neither a reptile nor a mammal,but a basal synapsid,i.e.,an early relative of theancestors of mammals.•Not all dinosaurs lived at the same time.Different dinosaurs lived at different times.Despite the portrayals in movies like King Kong and Jurassic Park,no Stegosaurus ever saw a Tyrannosaurus,because Tyrannosaurus didn't appear on the scene until 80 or so million years following the extinction of stegosaurs.The same goes for Apatosaurus ("Brontosaurus") —it's bones were already well-fossilized by the time T.rex came along.•Dinosaurs are not extinct.Technically.Based on features of the skeleton,most people studying dinosaurs consider birds to be dinosaurs.This shocking realization makes even the smallest hummingbird a legitimate dinosaur.So rather than refer to "dinosaurs" and birds as discrete,separate groups,it is best to refer to the traditional,extinct animals as "non-avian dinosaurs" and birds as,well,birds,or "avian dinosaurs." It is incorrect to say that dinosaurs are extinct,because they have left living descendants in the form of cockatoos,cassowaries,and their pals —just like modern vertebrates are still vertebrates even though their Cambrian ancestors are long extinct.。
