3 1. The answer of dinosaurs flying into the blue sky

Dinosaur is an animal that lived about 235 million to 65 million years ago and was able to walk upright on its hind legs. They have ruled the global terrestrial ecosystem for more than 654.38 million+600 million years. Most dinosaurs have been extinct, but the descendants of dinosaurs-birds have survived and multiplied to this day. In addition, in spoken language, dinosaurs refer to ugly women. The word "dinosaur" has two meanings in the dictionary: an ancient animal that lived hundreds of millions of years ago and is now extinct; (Internet language) A woman with bad looks in contemporary times.

Definition and basic attributes:

Dinosaur (English: Dinosaur) is a terrestrial animal that lived about 235 million to 65 million years ago and was able to walk upright on its hind legs. It is a diverse group of dominant vertebrates in Mesozoic. Most of them belong to terrestrial reptiles, but they can walk upright and rule the global terrestrial ecosystem for more than 654.38+0.6 billion years. It is said that it is a vertebrate rather than a reptile, because dinosaurs were once classified as reptiles, but it does not conform to a basic feature of reptiles, the crawling way of walking, and the cold-blooded animals that have been questioned.

Time of appearance and disappearance:

Dinosaurs first appeared in Triassic about 240 million years ago and died at the end of Cretaceous about 65 million years ago. Dinosaurs finally died out in Neogene Paleocene 63 million years ago.

The origin of the name "dinosaur";

In fact, human beings have a long history of discovering dinosaur fossils. Long before the discovery of Iguanodon, Europeans knew that there were many grotesque huge bone fossils buried underground.

It was not until Iguanodon was discovered and compared with iguana that the scientific community initially determined that it was a group of extinct lizard-like reptiles.

1842, British paleontologist Sir richard owen (1804- 1892) created a name for them in Latin, which consists of two roots, the former meaning "terrible" and the latter meaning "lizard". Since then, "scary lizard" has become a general term for a class of reptiles.

We in China have both imagination and generalization, and translated this Latin name into "dinosaur". Dinosaurs are not lizards at all.

The relationship between dinosaurs and birds;

1862 The archaeopteryx fossils found are very similar to those of Megalodocus, but the difference is that the archaeopteryx fossils have obvious feathers (Megalodocus also has feathers, but it is very primitive). In fact, quite a few carnivorous dinosaurs have primitive feathers, which indicates that dinosaurs and birds may be close relatives. Since 1970, many research reports have pointed out that modern birds are probably the direct descendants of theropod dinosaurs. At present, most scientists regard birds as the only dinosaurs that have survived and developed to this day, and a few even think that they should be classified into the same category in biology (that is, dinosaurs that have not yet been built). Crocodiles are modern close relatives of another kind of dinosaurs, but their relationship is farther than that between dinosaurs and birds. Dinosaurs, birds and crocodiles all belong to the evolutionary branch of reptiles, which first appeared in the late Permian and became the dominant fauna in the middle Triassic.

From the discovery of dinosaurs to the first 60 years of the 20th century, scientists and mass media regarded dinosaurs as lazy and slow-moving cold-blooded animals due to their lack of understanding of dinosaurs. However, since the revival of dinosaurs in 1970s, it has been suggested that dinosaurs may be active warm-blooded animals with social behaviors. Many recent evidences of the relationship between dinosaurs and birds support the view that dinosaurs were warm-blooded animals. But what is the truth needs further study.

Diversified development:

From the early Jurassic to the late Cretaceous, the dinosaur family adapted to the environment and developed rapidly, which led to the diversification of dinosaurs and the increase of dinosaur population, which gave dinosaurs an advantage and enabled them to dominate the terrestrial ecosystem of the earth. There are many kinds of dinosaurs, and their shapes and habits are quite different. Among them, the big one can be as big as dozens of elephants combined; Small, but almost like a chicken. As far as food habits are concerned, dinosaurs have mild vegetarians (dinosaurs that ate plants) and fierce carnivores (dinosaurs that ate animals), as well as omnivorous dinosaurs that ate both plants and plants.

Habit:

The oldest reptile fossils can be traced back to the "Pennsylvanian period" of Paleozoic (about 320 million years ago-280 million years ago). Tracing back to the source, it evolved from amphibians. Amphibian eggs need to be in water to start developing. Reptiles have evolved eggshells to prevent water from escaping from eggs. This major reform enables reptiles to survive without water.

From 245 million years ago to the Mesozoic era 65 million years ago, reptiles became the master of the earth's ecology, so the Mesozoic era was also called the reptile era. Large reptile dinosaurs appeared in the early Mesozoic. Herbivorous Liang Long and Myxosaurus are the largest land animals in size and weight. Tyrannosaurus rex is the largest carnivore on land. In addition, ichthyosaurs living in the sea, plesiosaurs and pterosaurs living in the air formed a complex and perfect ecosystem.

Reptiles have multiplied on the earth for about 65.438+0.8 billion years. Among the animals of this era, dinosaurs are the most widely known. When people mention dinosaurs, they will see a huge and fierce animal. In fact, there are also small and docile dinosaurs among dinosaurs.

Dinosaurs belong to vertebrate reptiles and once lived in swamps and bushes on Mesozoic land. Their hind limbs are longer than their forelimbs and have tails. Many of them are carnivores and many are herbivores. Among them, the slower-developing species are similar to the oldest crocodiles and beaks, and the more developed species are similar to birds.

Methods of studying dinosaurs:

The study of dinosaurs depends entirely on fossils. Paleontologists speculate on the shape and habits of dinosaurs through the study of dinosaur fossils. According to their research, dinosaurs are like living animals: there are big ones and small ones; Some walk on two legs, and some walk on four legs; Some eat plants, some eat animals, and some eat both animals and plants; Some have smooth skin, some have scales or bone plates, and more have feathers. The similarity is that all dinosaurs have small brains (except birds and some carnivorous dinosaurs) and lay eggs on land (all dinosaurs do).

A long time ago, there lived a group of strange creatures-dinosaurs. They dominated the earth, lived for nearly 65.438+0.7 billion years, and finally died out mysteriously. Everything we know about dinosaurs today comes from dinosaur fossils.

Scenes of the dinosaur era:

Dinosaurs lived on the earth for nearly 65.438+0.7 billion years. In such a long time, many changes have taken place in the environment of the earth. The Pangu continent, which was originally connected as a whole, gradually drifted and split into the familiar form. After these earth plates drifted around the world, the climate environment changed because the light was no longer uniform and the heat conduction was blocked by the ocean. In the early dinosaur era, the dwarf shrubs composed of ferns were the main vegetation on the earth. Plate drift, coupled with climate change, has caused great changes in plant species on the earth. However, because these changes took place gradually over a long period of time, the animals growing in them can still adapt well. However, due to the intensification of crustal movement and frequent geological activities in the middle period of dinosaur era, the land climate changed. In the late dinosaur era, the climate became dry and cold, and deserts appeared on the earth. As the earth's plates drift, the mountains are high and the valleys are heavy, and the plates move in different directions with the mainland, a series of changes have taken place in the environment.

The discovery of dinosaurs:

Unearthed fossils: in history, human beings discovered dinosaur fossils very early, but at that time, due to limited knowledge, they could not explain them correctly.

According to legend, as early as 1700 years ago, dinosaur fossils were found in Wucheng County, Sichuan Province (then called Shu County of Bashu). But people at that time did not know that it was the remains of dinosaurs, but regarded them as the bones left by the legendary dragons.

Long before Iguanodon (the first named dinosaur) was discovered in Mantels, Europeans knew that there were many grotesque huge animal bones buried underground. But at that time, people didn't know their exact ownership, so they were always mistaken for "the remains of giants."

Origin of the name: 1842, British paleontologist Charles Owen coined the word "dinosaur". English dinosaurs come from the Greek deinos (meaning terror) Saurosc (meaning lizard or reptile). For Owen at that time, this "scary lizard" or "scary reptile" refers to an extinct large reptile (actually it is not). In fact, not many dinosaurs were found at that time. Since the discovery of dinosaurs in Antarctica in 1989, dinosaur remains have been found in seven continents all over the world. At present, there are at least 650 to 700 species (biological species) of dinosaurs described in the world. Later, scholars in China, Japan and other countries translated him into a dinosaur, because there have been legends about dragons in these countries, which think that dragons are the length of scale worms and snakes are another name for dragons.

The story of prout Gallon Gallon comes from a researcher named Hastert of the University of Reading in England. According to the clues found in a historical novel "Mr. milken's Wife", after a long period of research and reading a lot of materials, he announced that he finally found the following research results: 1677 An Englishman named prout Gallon wrote a natural history book about Oxford. In this book, prout Gallon describes a huge fossil leg bone found in a quarry in the parish of Karovilla. Prout-Garonne province drew illustrations for this fossil, and pointed out that this thigh bone is neither cow's, horse's, nor elephant's, but belongs to a giant bigger than them.

Although prout-Garonne Province didn't realize that this fossil belonged to a dinosaur, or even associated it with reptiles, the specimen he described in written records and illustrations has been identified by later paleontologists as the thigh bone of a dinosaur called Megalodon (now known as Bancrosaurus), and this fossil was discovered earlier than the first named dinosaur Iguanodon in Mantels 145 years. Therefore, Hastert thinks that prout-Garonne-Garonne should be the first discoverer and recorder of dinosaur fossils on record.

Species of dinosaurs

Dinosaurs belong to: biology-eukaryote (eukaryote)-animal kingdom-Chordata-Vertebrate-Tetrapod Superclass-sauropod (reptile)-Diptera-sauropod; An extinct animal.

It is listed as a general order in biology.

The biggest difference between dinosaurs and other reptiles lies in the posture of standing and the way of marching. Dinosaurs are completely upright, with their limbs directly under their bodies. This structure has more advantages than other reptiles (such as crocodiles, whose limbs extend outward) when walking and running. According to the different structural characteristics of dinosaur belts, they can be divided into two categories:

Lizards, birds and buttocks.

The main difference between them lies in their belt structure:

The belt of sauropods is three-shot in side view. The pubic bone extends forward under the intestinal bone and the ischium extends backward, similar to lizards. Very ugly.

The waistband of ornithischia expands greatly in the front and back of the intestinal bone, and there is a large pubic protrusion on the front side of the pubic bone, which extends below the intestinal bone, and the back side extends parallel to the ischium to the front and bottom of the intestinal bone. So from the side, the pelvis is radiant. Besides, there are other differences. )

Sauropods are divided into sauropods and theropods.

Sauropods are divided into protosauropods and sauropods.

Protosauropods mainly lived in the Late Triassic to the Early Jurassic, and were omnivorous medium-sized dinosaurs, such as Ban Long, the first giant dinosaur living on the earth, and Ankylosaurus living in the Early Jurassic.

Sauropods mainly live in Jurassic and Cretaceous. Most of them were giant vegetarian dinosaurs. Small head, long neck, long tail and small teeth in spoon shape. The famous representative of sauropod is Mamenxilong, which was produced in Sichuan and Gansu provinces of China in the late Jurassic. It consists of 19 cervical vertebrae and is the largest known animal in the world-Zhenlong or fragile double-chambered dragon.

Theropod dinosaurs lived from the Late Triassic to the Cretaceous. They are all carnivorous dragons, walking on two feet, with sharp claws on their toes, well-developed heads and teeth as sharp as daggers or knives in their mouths. Tyrannosaurus rex is a famous representative, and the others, such as Allosaurus and the southern behemoth, are also famous.

The suborder ornithopoda can be divided into five categories: ornithopoda, stegosaurus, Ankylosaurus, Ceratosaurus and pachycephala.

Ornithopoda is a group with the most fossils in ornithopoda and even the whole dinosaur category. They walk on two or four feet. The mandible has a single anterior tooth bone, and the teeth only grow on the cheeks. The crowns of the maxillary teeth bend inward and the crowns of the mandibular teeth bend outward. They lived from Late Triassic to Cretaceous, and they were all vegetarian dinosaurs. Such as: hadrosaurs, Iguanodons, etc.

Stegosaurus was a quadruped with an upright bone plate on its back and two or more pairs of bony spines on its tail. It mainly lived from Jurassic to early Cretaceous, and was the first large extinct dinosaur group. Its representative is Stegosaurus, which was thought to live on the plain and was found in ken dragon.

Ankylosaurus dinosaurs were short and stout, covered with bone decks, and ate plants, mainly living in the early Cretaceous. For example, the sea dragon living in continental Europe and the Ankylosaurus living in Britain.

Ceratosaurus is a four-legged vegetarian dinosaur. The back of the skull expanded into a cervical shield, most of which lived in the late Cretaceous. The parrot-billed dragon found in northern China belongs to the ancestor type of Ceratosaurus. Among them are Triceratops, the docile herbivorous dinosaur protoceratops and so on.

The main characteristics of pachycephalosaurus are that the skull is swollen and thick, the hole is closed, and the pubic bone in the pelvis is rejected by the ischium and does not participate in the formation of the band. It mainly lived in Cretaceous.

Whether sauropods or birds, their belts leave a small hole between the intestine, ischium and pubis, which other reptiles do not have. It is this hole that shows that these two animals, called dinosaurs, are the closest relatives compared with all other reptiles.