Jurassic is the heyday of dinosaurs, and the dinosaurs that appeared and began to develop in Triassic have quickly become the rulers of the earth. All kinds of dinosaurs came together to form a world of dragons with different shapes. At that time, in addition to the giant confusing dragon, Liang Long and Brachiosaurus on land, ichthyosaurs and dragons in water also had great development and evolution.
Second, the scientific community has not reached a unanimous conclusion on the reasons for the extinction of dinosaurs. Here are some recognized reasons for the extinction of dinosaurs:
1, Plant Poisoning: At the end of the dinosaur era, gymnosperms on the earth gradually became extinct and were replaced by a large number of angiosperms, which contained toxins that gymnosperms did not have. Giant dinosaurs ate a lot, and the intake of angiosperms led to excessive accumulation of toxins in the body and finally poisoning. Carnivores are poisoned after eating poisonous meat.
2. Climate change theory: 65 million years ago, the earth's climate suddenly changed and the temperature plummeted, which led to the decline of oxygen content in the atmosphere and dinosaurs could not survive. Some people think that dinosaurs were cold-blooded, without hair and warm organs, unable to adapt to the decline of the earth's temperature, and all of them froze to death.
3. Loss theory of silica gel: The muscles of dinosaurs belong to an organic silica gel, and the silicon content in dinosaurs is higher than that in animal ancestors, and the silicon content in animal ancestors is higher than that in animals. Dinosaurs were extremely dependent on silane. Dinosaurs ate animals and plants with polymer silica gel or silicon structure, and gradually became extinct with the decrease of food they relied on.
4. Comet impact and volcanic eruption: After continuous research, scientists finally found definitive evidence. 65 million years ago, a huge comet hit the ground. Through the internal oscillation theory, it is pointed out that the opposite side of comet impact leads to volcanic eruption. Of course, these are not enough to make dinosaurs extinct.
What really made dinosaurs extinct was that after the volcano erupted, the volcano carried a lot of anaerobic bacteria and turned oxygen into a toxic chemical gas. Hundreds of thousands of years or even longer. The oxygen content in the air becomes extremely scarce. Small mammals can continue to survive.
But the giant dinosaurs lost their viability. So in order to continue to reproduce, the body will continue to shrink. It gradually evolved into other bird-like species. The reason why insects become so small today. It is also because there is too little oxygen in the air that they can't get enough oxygen to drive their huge limbs.
Extended data:
Physical characteristics of dinosaurs:
Dinosaurs as a whole are very big. According to dinosaur standards, lizard's foot is one of the behemoths. In the long dinosaur era, even the smallest sauropods were larger than other animals in their habitats, while the largest sauropods were several grades larger than any animals that appeared on the surface.
Most dinosaurs were much smaller than large sauropods. The existing evidence shows that the average size of dinosaurs changed constantly in Triassic, Early Jurassic, Late Jurassic and Cretaceous. Most theropod dinosaurs weighed between 100 and 1000 kg, while most Holocene carnivores weighed between 10 and 100 kg.
The estimated weight of dinosaurs is mostly between 1 and 10 metric tons. A study by the National Museum of Natural History in London pointed out that the average weight of dinosaurs was about 100 kg, while the average weight of new generation mammals was between 2 and 5 kg.
Judging from the existing intact bones, the tallest and heaviest dinosaur is the long-necked dragon. The fossil of long-necked dragon was found in Tanzania from 1907 to 19 12. A skeleton model composed of several individuals of similar size is now on display at the Humboldt Museum in Berlin. The model is 12 m high and 22.5 m long, and the estimated live weight is between 30 and 60 metric tons.
The longest dinosaur is Liang Long, which is 27 meters long. It was discovered in Wyoming, USA on 1907 and is now on display at Carnegie Museum of Natural History in Pittsburgh, Pennsylvania.
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