The first dinosaur bone fossil was discovered and collected by Robert prout, the curator of Oxford Museum in England, in 1677. More than a hundred years later, many explorers and scholars discovered and studied the fossils belonging to dinosaurs, but almost none of them were correctly identified.

184 1 year, paleontologist richard owen put forward the word "dinosaur" for the first time based on some large reptile fossil specimens, which originated from the Greek words "deinos" (meaning terror) and "sauros" (meaning lizard) and was translated as "dinosaur" by Japanese and China scholars.

After the concept of "dinosaur" came out, scholars carefully observed and identified the dinosaur fossils found, and carried out further excavation work. The excavation of Asian dinosaurs was not carried out until after the 20th century. The earliest dinosaur fossils in China were found in 1902 (Heilongjiang), and then a large number of dinosaur fossils were found in many parts of the country, including Lufeng in Yunnan, Laiyang in Shandong, Zigong in Sichuan, Tibet, Inner Mongolia and other places. Lufeng and Zigong also established dinosaur museums respectively, and held the "Lufeng First Dinosaur Festival" in 199 1. China can be called "the dinosaur country of the world".

So far, there are more than 2000 dinosaur fossils (including bones, teeth, skin, eggs, feces, footprints, etc. ) Digging around the world. It has been identified that there are more than 800 species belonging to more than 350 genera of 2 orders and 7 suborders (some scholars believe that the number of dinosaurs surviving on the earth is between 900- 1200 genera), and there are more than 80 genera in China.

The earliest dinosaur fossils have been excavated about 230 million years ago. It is generally believed that dinosaurs were differentiated from the original crocodiles. At first, dinosaurs were some bipedal carnivorous dinosaurs. By the end of Triassic, the evolutionary branch of dinosaurs was basically established. By the end of Jurassic, dinosaurs developed greatly, surpassing the pioneers of Triassic in species and quantity, and became the real rulers on the earth. Extensive adaptive radiation has also emerged.

"dinosaur" is not a taxonomic term, but a popular name. There are two kinds of dinosaurs:

1. sauropods' main feature is that the structure of ilium, ischium and pubis that make up the belt is similar to that of other reptiles, that is, a belt with three guns or three guns. It is divided into two sub-orders:

(1) Theropoda: Tyrannosaurus Rex, Deinonychus, Slender Dragon, Slender Dragon, etc.

(2) sauropods: Liang Long, Lei Long, Lufenglong, Mamenxilong, etc.

2. The main feature of flapping-wing machine is that the structure with bone is similar to that of birds, and the pubic bone is backward, that is, the four-shot or four-shot belt, and there are also front teeth and buccal muscles. It is divided into five suborders:

(1) ornithopoda: Iguanodon, duck-billed dragon, etc.

(2) Ceratosaurus: protoceratops, Ceratosaurus, Parrotbill, etc.

(3) Ankylosaurus: Arthropod, Spinosaurus, Ankylosaurus, etc.

(4) Stegosaurus: Stegosaurus, etc.

(5) Leonidas: pachycephalosaurus, etc.

Dinosaurs were all extinct in the late Cretaceous of Mesozoic-early Paleocene of Cenozoic 60-70 million years ago. This ancient animal group, which has lived on the earth for more than 100 million years, mysteriously disappeared on the earth, causing many scholars to guess and explain the reasons, and it is still inconclusive. There are several explanations that still occupy a place in today's scientific community: asteroid impact theory (Becker theory), periodic extinction theory (Nemesis theory), climate deterioration theory, community succession theory, etc. The main reason why these explanations are not recognized is that they can't be justified and can't perfectly explain why dinosaurs became extinct in about 500 ~ 654.38+00000 years.

The reasons for the extinction of many reptiles, such as dinosaurs, are described in junior high school zoology textbooks, which belong to the theory of climate deterioration and gradual change. Skeptics believe that dinosaurs formed considerable adaptability to various environments in the long-term evolution process, otherwise they would have been eliminated. The deterioration of the earth's climate should be gradual or local, and dinosaurs seem to be able to adapt or avoid it slowly. In the early and middle Mesozoic, there were many major changes in landform and climate, but dinosaurs were not greatly affected. Even if the deterioration of the earth's climate will lead to the extinction of dinosaurs, it is partial. This is not the case all over the world. There are also some small areas with little climate change, where dinosaurs will not be extinct at the same time as dinosaurs in other places. In short, the real reason for the extinction of dinosaurs is still unclear. I believe that the mystery of the extinction of dinosaur families will be solved one day.

For nearly half a century, scientists have accumulated some information about the biological characteristics of dinosaurs.

Dinosaurs' limbs (especially belts) are similar to those of mammals (that is, they can stand upright under their bodies and walk or run with their heads held high on the ground). Dinosaurs of general size (several meters to more than ten meters in length) usually have a stride of about 2.75 ~ 5 meters and can reach 5 ~ 8 meters when running; The running speed of small dinosaurs can reach 35 ~ 40km/h, that of large dinosaurs can reach 15 ~ 20km/h, and the slowest one is only 3.5km/h. ..

Most dinosaurs were herbivores. They ate a lot. Sauropods weighing several tons to dozens of tons eat more than 100 kilograms or even more than one ton a day. There are few kinds and numbers of carnivorous dinosaurs. According to statistics, only 3 ~ 5 of every 100 dinosaurs are carnivorous.

Dinosaurs are oviparous animals, and a few may be oviparous. During the reproductive period, males often fight for females or seduce their spouses with euphemistic guttural sounds. Eggs are 80 ~ 300mm in diameter and 2 ~ 7mm in shell thickness. Most of them are hatched by sunlight, and a few may hatch like hens. Some newly hatched young dinosaurs are well developed and can move freely; Others are underdeveloped and weak, and need careful care and feeding from their mothers for a period of time before they can live independently (for example, the duckbill dragon is also called "the mother dragon"). Dinosaurs generally live for several years to decades, and a few can live for as long as a hundred years.

Scientists usually think that dinosaurs were "warm-blooded animals", but now some scholars think that some dinosaurs may be "warm-blooded animals". Barker, a famous American vertebrate paleontologist, believes that the energy conversion rate of warm-blooded animals is low, and Haversian blood vessels are few. Haversian blood vessels are the exchange place of calcium and phosphorus in bones, while warm-blooded animals have abundant blood vessels to meet the needs of energy metabolism. After comparing the microstructure of long bone grinding plates of lizards, dinosaurs and mammals, Buck thought that dinosaurs might have "thermostats". When dinosaurs walked and ran, they usually relied on the long tail, long neck, bone plate on the body surface, enlarged nasal cavity and large venous sinus in the brain to dissipate heat.

Dinosaurs have scales on their bodies, and some may have feathers or hairy skin derivatives. They may have as rich colors as birds, especially small and medium-sized species. The color of larvae is more dazzling than that of adults, while the color of large species is monotonous. The species living in the Woods are mixed with green, brown or yellow, while the species in the wilderness are mostly black and white.

Many people think that dinosaurs are huge and terrible animals, which is not comprehensive. Some dinosaurs are really big (the dragon is 42.67 meters long), but some dinosaurs are almost as big as chickens.

According to various studies, the characteristics of dinosaurs can be described as follows:

There is a socket in the belt. Vertebral healing is recommended for II ~ VII. Four feet or two feet stand upright under the body and walk on the ground with phalanges, with 3 ~ 5 claws or hooves at the toes; Rough skin, covered with scales or bone nails; It is a warm-blooded animal, oviparous (a few may oviparous); Most of them have teeth, are mostly phytophagous and eat less meat; The skull structure is similar to that of a crocodile.

References:

Middle school biology

Running dinosaur

After printing out the fossils, Alexander made a judgment that many large four-legged sauropods are really slow-moving "idiots", and their walking speed is only about 1 m per second, which is close to the walking speed of human beings. The footprints of large biped dinosaurs show that their walking speed is generally less than 2.2 meters per second, which is similar to the speed when humans walk quickly. The footprints of those smaller bipedal dinosaurs weighing about 500 kilograms (similar to the size of a horse race) show that they can run at a speed of 12 meters per second, which has exceeded the highest speed of the human 100-meter race champion (1 1 meter per second), but it is still far below the running speed of horse races (about1meter per second)

pterodactyl

Chiroptera lived in Cretaceous, and their bones were found in Europe. Pterosaur is not very big, 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 once found a pterosaur whose wings were more than 15 meters long. If we can see it today, maybe you will think it is a plane flying in the sky. 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.

How did pterosaurs fly into the sky?

Scientists have different views on this. Some people think that those giant pterosaurs can't fly at all and can't flap their wings like birds, but they can climb high first, spread their huge wings against the wind and glide in the air with the help of updraft. Some people think that the membrane on pterodactyl wings is very hard, and the bones and muscles on the outside of the wings are connected together like a frame, which can flap the wings like a bird. Because of their wings,

Eel dragon

Eel dragon is a kind of plesiosaur. Their fossils were found in Japan. According to measurements, they are about 7 or 8 meters long, and they have sharp teeth.

Triceratops

Triceratops is a kind of ceratosaurus. It has a horn on its nose, like a rhinoceros, and two horns on its eyes, like an ox. All three corners are 1 meter long, which is a powerful weapon for them to fight.

brontosaurus

Lei Long is the largest dinosaur, some of which are more than 30 meters long and as high as six floors. Are herbivores or leaves. Most dinosaur fossils we see in museums are of this type.

Allosaurus

Allosaurus is a fierce and terrible carnivorous dinosaur. Its big mouth can swallow a pig at once. Its teeth are all bent inward, and its prey can't escape when bitten.

material

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_ _ _ _ _ The scene of the dinosaur era

Dinosaurs lived on the earth10.5 billion years ago. During such a long time, the environment of the earth has also changed a lot. Pangu, which was originally connected as a whole, gradually drifted and split into the form we know now. After these continents drifted around the world, the climate and environment also changed. Land mass drift, coupled with climate change, has caused great changes in plant species on the earth. However, because these changes are gradually formed in a very long time, the animals growing in them can still adapt well. In the early dinosaur era, the dwarf shrubs composed of ferns were the main vegetation on the earth. Later, tall coniferous forests and low cycad jungles replaced ferns and became the main plant landscapes on the earth. Soon after, the first flowering plants appeared, and the plant landscape on the earth changed greatly. At that time, dinosaurs depended on many plants and flowers.

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Meat eaters

Carnivorous dinosaurs are large dinosaurs with big heads, strong hind legs and short forelimbs. They all belong to theropod, and are often called carnivorous dragons or carnivorous lizards. Carnivorous dinosaurs walked on their hind legs. Because their hind legs bear huge body weight, they may not move very fast. Their heads are very big, their jaws are very long, and the whole row of huge curved teeth on the jawbone looks like the serrations on the blade of steak knife. Carnivorous dinosaurs mainly ate other dinosaurs and sometimes ate animal carcasses. They may kill their prey with the claws of their hind legs first, and then use the teeth and claws of their forelimbs. Tear off the meat of the prey and eat it. Osteosaurus is also a carnivorous dinosaur, but they are completely different from ordinary carnivorous dinosaurs. Osteosaurus is light and agile, with a pair of long arms and palms that are easy to grasp, and a long and narrow jawbone. They run very fast and prey on small mammals and insects. In addition, Bonosaurus often picked up the remaining debris to eat after large carnivorous dinosaurs had eaten.

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vegetarian

Many dinosaurs were herbivores, including the largest sauropods and all ornithopods. In fact, it was much more troublesome for dinosaurs to eat plants than meat, because plants were composed of cellulose and lignin, and these tough substances had to be decomposed before they could be digested by their stomachs. In order to solve this problem, herbivorous dinosaurs have evolved various solutions. For example, sauropods did not chew at all, but swallowed the food they had bitten directly. Let the bacteria in the stomach ferment food or deliberately let them eat pebbles to grind food. Duckbilled dinosaurs have special teeth, and they can crush food first. Ceratosaurus dinosaurs tore up tough plants with unusually strong jaws and sharp teeth.

The extinction of dinosaurs

At the end of the Cretaceous period 65 million years ago, scientists have been arguing about what happened to make dinosaurs and a large number of other creatures extinct. Some people say that there was a geological orogeny on the earth at that time, because many mountains grew on the flat land, swamps decreased and the climate became less humid and warm. Dinosaurs' respiratory organs could not adapt to dry, cold and dry air. In winter, dinosaurs' food was gone. So I walked into a dead end. Some people say that the supernova explosion caused a strong change in the earth's climate, and the temperature suddenly rose and then dropped very low. Others say that dinosaurs ate a lot of flowering plants, and there were many toxins in these flowers. Dinosaurs ate a lot, so they died of poisoning. The evidence is that flowering plants began to appear at that time. Others ingeniously said that it was because dinosaurs, a huge animal, ate too much and kept farting. A large amount of methane gas is released into the air. Because they are too numerous and live for a long time, the ozone layer of the earth is destroyed and the climate is devastating. Some people even say that it is the result of aliens hunting on the earth, because they think dinosaur meat is particularly delicious. The evidence is that the dinosaur bone fossils they found in the North Pole have traces of laser cutting. In short, there are all kinds of surprises. However, the theory of meteorite impact has been widely recognized.

__ 1980, American scientists found a high concentration of iridium in the stratum 65 million years ago, which was dozens or even hundreds of times higher than the normal content. Such a high concentration of iridium can be found in meteorites, so scientists associate it with the extinction of dinosaurs. According to the content of iridium, it is also calculated that the impact object is an asteroid with a diameter of 10 km. Such a large meteorite hit the earth, which is definitely an unparalleled blow. According to the earthquake intensity, it is about Richter scale 10, and the diameter of the crater produced by the impact will exceed 100 km. It took scientists 65,438+00 years and finally got the preliminary results. They found this crater in the stratum of Yucatan Peninsula in Central America. According to the calculation, the diameter of this crater is 65438+.

_ _ _ Scientists began to describe the heroic scene 65 million years ago for us. One day, dinosaurs were still eating and drinking carefree in paradise on earth. Suddenly, a dazzling white light appeared in the sky, and a boulder with a diameter of 10 km fell from the sky. It was an asteroid that fell into the sea at a speed of 40 kilometers per second and hit a huge one at the bottom of the sea. Steam sprayed tens of thousands of meters into the sky, and then the tsunami was as high as 5 kilometers and spread at an extremely fast speed. The turbulent sea swept everything that landed on land, and the turbulent waves swept the earth's surface, and then merged at the back end of the impact point. The huge sea power triggered a strong volcanic eruption in Deccan Plateau here, which changed the movement direction of the earth plate. What a terrible disaster this is. Meteorites hit the earth and produced a lot of dust. The polar snow melts, plants are destroyed and volcanic ash fills the sky. For a time, the sky was dark, the temperature plummeted, and it rained heavily. Mountain torrents and mudslides swept away the dinosaurs and buried them. In the next few months or even years, the sky is still dusty and overcast, and the earth enters a low temperature because it has not seen the sun all the year round, and the vast land is silent for a while. Therefore, an era in the history of biology is over.

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A grotesque head

Some dinosaurs have very strange heads, such as strange protrusions or bony protrusions on their heads-they may be small pieces, protrusions, crescent moons, spines or helmets. These strange head shapes have the same eye-catching effect as the special structures or bright spots on existing reptiles, birds or mammals. Their striking shapes may be used to attract the opposite sex, scare off enemies or express their good mood or bad mood. In addition, the bony process on the head is also a weapon for defense or attack, which can be used as a natural helmet and a tool for hard collision. Among many grotesque heads, the most unique one is the head of hadrosaurs. Hadrosaurs are named for their wide, flat, toothless, duckbill-like beaks.

The end of the dinosaur era

At the end of Cretaceous, dinosaurs became less and less, and finally disappeared completely. At the same time, the landform of the earth has changed. Because of the expansion of the seabed, Pangu continent was divided into several pieces. The rising sea level has turned many low-lying areas where dinosaurs lived into Wang Yang. Many kinds of marine animals have also become extinct. In addition, the warm climate all year round is now becoming more changeable or seasonal. The species of plants have also changed.

Double crown dragon:

_ _ _ It has two protruding ridges on its head, which is 6 meters long and eats carrion. Its forelimbs are short and it is good at running. In the early Jurassic, carnivorous dinosaurs were 6 meters long and stood with their heads about 2.4 meters high. He has two big bone crowns on his head, so he is named double-crowned dragon. His nose and the front end of his mouth are very narrow, soft and elastic. He can take them out from the crevices of bushes or stones and eat those tiny lizards or other small animals. Compared with the later large carnivorous dinosaurs, the body of Diplodocus was slim, so it moved quickly. Its mouth is full of sharp teeth, and it can kill some large herbivorous dinosaurs. However, some scientists doubt its tooth function and say that it is just a dinosaur that eats carrion.

Legend of dinosaurs

A long time ago, about 200 million to 70 million years ago today, there lived a huge family on our earth. They rule the sea, land and sky, and all other animals can't compete with them. They are veritable overlords, that is, dinosaurs.

At that time, the earth's climate was warm and humid, and there were dense forests everywhere. There are all kinds of animals living in the forest. Therefore, no matter whether dinosaurs ate plants or animals, they could not finish eating them. Because of such a good environment, dinosaurs generally grew huge. It is speculated that the largest dinosaur was 30 meters long and weighed 40 to 50 tons, even the largest bus now.

However, such a huge family suddenly disappeared from the earth. It disappeared at what scientists call the end of Cretaceous. Why dinosaurs suddenly disappeared so cleanly is a scientific mystery. People have been speculating for many years, but there is never a clear answer. Fortunately, some dead dinosaurs did not disappear completely. Their bones became fossils and were preserved by nature. Today, we know that some animals existed in the past, and we described their appearance according to these bones. If you are interested in dinosaurs, give it a try and see if you can solve this eternal mystery.

The study of dinosaurs is very meaningful. It can not only help us understand the evolution of life on the earth, but also help us understand the changes of the earth's climate, the situation of geological activities, the relationship between ourselves and the environment, and even all aspects of celestial bodies in the universe. How's it going? Very interesting. Please follow us to have a look. However, because there are many beautiful pictures, the speed may be slower, so don't worry.

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_ _ _ _ the most dinosaurs

_ _ When you walk through the shop window, do you feel strange or curious because of that oversized music bottle or petite cartoon doll? Do you want to know what the smallest dinosaur is, the longest and the largest?

1. The smallest dinosaur

_ _ _ in the known dinosaur species, the smallest is the narrow jaw dinosaur, but this dinosaur is only as big as a chicken. Some species are only about one meter and forty centimeters long; Some are only seventy centimeters! Although it is a little bigger than a chicken, some dinosaurs, including the long tail, may be smaller than the brachiosaurus, but they are only obtained from sporadic fossils, such as sauropods, a carnivore with sharp claws as big as cats. Smaller than fine jawed dinosaurs and sauropods are the larvae of some dinosaurs: parrot-billed dinosaurs are only 25 cm long, while newly hatched sauropods are only 20 cm long, not much bigger than robins. A paleontologist speculated that this adult may be as long as 6 meters. But it was not until the real Ratatosaurus was discovered as an adult, which is only speculation! _

2. The ugliest dinosaur

_ _ I think Houdanlong is the ugliest of those ugly dinosaurs. Houdanlong belongs to the dinosaur with a protruding top. Its skull is covered with an arc-shaped bone plate about 23 cm thick. Around this bulge, rows of small tumors and mucro surround the smooth hills, just like a tumor. Its front edge looks like it has been tortured by some unspeakable bone disease, and its nose is covered with tumor-like lumps. Spine. These surrounding tumor spines and spines make the protruding part of the head look like it has been shaved. Compared with pachycephalosaurus, the second ugliest guy may be pachycephalosaurus. It is also Ceratosaurus, with a short and prominent ornament above its nose, which looks like a tree trunk left by sawing on its skull. _

3. The longest dinosaur

_ _ _ heavy dragon, both of which are about 27 meters long with Liang Long. However, it is possible to temporarily nickname the super dragon and the dragon. If all the skeletons are dug out, it will be longer. According to preliminary estimation, the length of these two types exceeds 10 to 35 meters respectively.

4. The heaviest dinosaur

Brachiosaurus and Antarctic dragon are estimated to be between 63 and 72 metric tons (70-80 tons), but Antarctic dragon may be thinner, but no one knows for sure.

Verb (abbreviation of verb) the widest dinosaur _

Ankylosaurus The crawling tank car in the dinosaur world, Ankylosaurus, although not more than ten meters long, is about five meters wide. _

6. The earliest dinosaurs _

The earliest known dinosaur was a bipedal carnivore named Southern Cross Dragon. It appeared in the Middle Triassic and was about 1.5 feet long.