Information about dinosaurs?

230 million years ago, the first dinosaur was as big as a dog. It supports its body with two hind legs. Tens of millions of years later, its descendants have multiplied into huge families with different shapes: some run on two feet and some walk on four feet; Some are big, some are small; Some are fierce, others are docile. Some carnivorous dinosaurs gradually became smaller and looked more and more like birds. Their bones are hollow, their skulls are enlarged, their bodies are light, their movements are agile, their forelimbs are getting longer and longer, they can flap like the wings of birds, and they grow feathers without scales and nails. Some people jump and land in trees to avoid enemies or find food, and then they can fly. The feathered dinosaurs on the ground ran and learned to fly. So a dinosaur evolved into a bird and flew into the blue sky.

Pterosaurs are close relatives of dinosaurs, living in the same era, and reptiles flying in the blue sky are sometimes mistaken for "flying dinosaurs". Pterosaur originated in the Late Triassic about 2.65438+0.5 million years ago, 6? 5 million years ago, at the end of Cretaceous. When dinosaurs ruled the landing site, pterosaurs controlled the sky. ?

Pterosaur is a very special reptile with unique skeletal structure characteristics. As early as 1784, when Italian paleontologist Coligny discovered the first pterosaur fossil in Germany, he was not even sure what kind of animal it belonged to. Some people think it lives in the ocean, others think it is a transitional type between birds and bats, and so on. It was not until 180 1 that Ju Yewei decided that it was a pterodactyl and a reptile. ?

Pterosaurs can't fly freely and long distances in the blue sky like birds. They can only glide near their living environment, such as rocks or Woods by the sea or lake, and sometimes hover on the water. ?

Pterosaurs predated birds by about 7? OOO flew to the sky for thousands of years, and began to adapt to air life in the late Triassic, and successfully survived on the earth for 65.438+0.5 billion years. In order to meet the needs of flight, pterosaurs have many skeletal characteristics similar to birds, such as porous skulls, hollow and light bones, sudden sternum and keel, and so on. ?

Up to now, more than 120 species of pterosaur fossils have been found and named in the world. The individual size and shape of pterodactyl vary greatly, such as the pterodactyl fossils found in Texas in the 1970s. Its wings spread about 16m, and its width is equivalent to F- 1? 6 fighter planes, small like sparrows. There are two kinds of pterosaurs. Early beaked dinosaurs were primitive, mainly living in Jurassic, with long tails. Late pterosaurs mainly lived in Cretaceous, and their tails were very short or even disappeared. ?

Pterosaurs are reptiles, but they are probably warm-blooded animals. 2? At the beginning of the 20th century, British paleontologists speculated that pterosaurs were warm-blooded animals with constant temperature, fast movement, bat-like hair and similar living habits to birds. Later, hair marks were found on the fossil of the beak-billed dragon found in Germany. 1970 A relatively complete pterodactyl fossil was found in Kazakhstan. British paleontologists believe that this specimen is undoubtedly a warm-blooded animal by studying its hair and pterygoid membrane structure. These "hairs" on pterosaurs are heat-insulated, preventing heat loss in the body and having the function of regulating body temperature. Another evidence comes from the bones of pterosaurs, which, like birds, had some small air sacs to regulate their body temperature. The "hairy" Jehol pterosaur recently discovered in western Liaoning, China, further proves that at least some small pterosaurs are warm-blooded animals. More and more fossil evidence shows that some pterosaurs have physiological mechanisms of internal heat and constant body temperature, high metabolic level, developed nervous system and efficient circulatory and respiratory systems, which can meet the needs of flight and become the least reptile-like species.

And archaeopteryx, the dragon bird?

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