I. Model essay 1
Dinosaurs A long time ago, about 200 million years ago from today, we lived in a big family on the earth. They rule the sea, land and sky, and all other animals can't compete with them. They are the real overlords, and this is the dinosaur.
There are many kinds of dinosaurs. According to the shape of their skeletal fossils, scientists divide them into two categories, one is called bird dragon and the other is called sauropod. Chiroptera lived in Cretaceous, and their bones were found in Europe. One-handed dragon is not a monster, its wings are only about 22 cm. But the wings of Fengshen Pterosaur were as long as 12 meters, which was as big as a bus.
American scientists have discovered a kind of wing, the length of which exceeds 15 meters! If we see it today, we will think it is a plane soaring in the air. Many flying birds and dragons are a bit like bats today. They seem to hold up huge wings with one hand, so having wings and claws has become a major feature of them. Some people think that later birds evolved from them.
Scientists found a small dinosaur fossil outside protoceratops's nest. What did it do in protoceratops's nest? After research, it turns out that stealing dinosaur eggs is a bad thing. It has no teeth in its mouth, only a sharp thorn. That's what she used to pierce and suck the egg juice.
On our earth, many creatures once appeared and then disappeared, which is an inevitable stage of biological evolution. But why a huge and dominant family like dinosaurs suddenly disappeared from the earth, which caused us to speculate.
Second, the model essay 2
Everyone has seen elephants, and they all say that they look like very big animals on land. In fact, there are animals much bigger than elephants-dinosaurs! Although there are no dinosaur footprints in the society now, people can clearly see living fossils!
The biggest dinosaur is a real dragon. It is 39 to 52 meters long, 18 meters high and weighs 130 tons. Then the smallest dinosaur is the beautiful jaw dragon, which is only 60 cm long and weighs less than a chicken.
Cretaceous, like other paleogeological ages, has obvious and clear rock marks, but the exact time of its beginning cannot be determined very accurately, with an error of several million years.
The end time of the Cretaceous is relatively accurate, about 65.5 million years ago. Cretaceous is the last period of dinosaur life, and it is also a period of great changes in the earth's landform. When the sea level reached a record height, the shape of the continent was very similar to today. Flowering plants appeared, and so did many insects from bees to ants.
The monitor lizard and the giant turtle swim together in the ocean. In the air, pterosaurs spread their wings to 12 meters. On land, dinosaurs dominate, and their size and shape exceed all previous types. Herbivorous dinosaurs grew to100t, and carnivorous dinosaurs grew to12m.
Dinosaurs died out in the Cretaceous-Tertiary extinction event 65 million years ago. The usual explanation is that a huge meteorite hit the earth, causing species extinction. But this theory is still controversial. Now we can only see dinosaur fossils in the science and technology museum.