Dinosaur Explanation 1: Girls with bad looks are often called "dinosaurs" on the Internet.

Explanation 2: Paleozoic creatures.

Detailed description is as follows. Dinosaurs are reptiles that appeared 245 million years ago and flourished at the end of the Mesozoic Era 65 million years ago.

Dinosaurs suddenly disappeared at a certain period and became a mystery in the history of biological evolution on earth. This mystery is still unsolved by no one.

The earth's past creatures are all recorded in fossils.

Many dinosaur fossils have been found in the strata of the Mesozoic Era.

A large number of bones or bones of various shapes can be seen among them.

However, in the subsequent Cenozoic strata, no dinosaur fossils can be seen at all.

It is inferred that the dinosaurs became extinct together during the Mesozoic Era.

There have been many opinions on the real reason for the extinction of dinosaurs since ancient times, but there is no definite argument. Therefore, it is still an unsolved mystery so far. Here are some of the more well-known theories as follows:

: 1. Meteorite collision theory: Sixty-five million years ago, a huge meteorite hit the earth, causing the extinction of the dinosaurs that had ruled the earth for tens of millions of years.

This theory was developed by Louis B. of the University of California, Berkeley.

Proposed by four scientists including Dr. Albarez.

This huge meteorite is about ten kilometers in diameter.

The crater terrain created by the impact has a diameter of 200 kilometers.

The energy generated by the impact, if converted into yellow gunpowder, is equivalent to one million billion tons (megaton).

Dust diffuses through the atmosphere into the stratosphere.

This caused the Earth to remain in darkness for several months.

During this period, many creatures, including dinosaurs, became extinct.

2. Comet collision theory: The "comet collision theory" is based on the paleontologist——David.

Raup and John.

It started with Sepkoski's thesis that "the extinction of ancient organisms occurs every 26 million years."

Louis.

Albarez sent this argument and his theory to astrophysicist Charles.

Later, Mullah believed that it was due to the gravity of Nemesis, the half-star of the sun, which periodically pushed comets towards the earth.

3. Orogeny theory: The orogeny that occurred at the end of the Cretaceous caused the swamps to dry up, and many dinosaurs that made the swamps their home could no longer live.

Because of the changes in the atmosphere, the plants also changed. Herbivorous dinosaurs could not adapt to the new food and became extinct one after another.

The herbivorous dinosaurs became extinct, and the carnivorous dinosaurs also lost their support and became extinct as a result.

This extinction process lasted for 10 to 20 million years.

By the end of the Cretaceous period, they were finally extinct on the earth.

4. The theory of climate change: As a result of the movement of tectonic plates, ocean currents change, causing huge changes in climate.

The severe cold climate caused plants to die, and the dinosaurs lacked food and led to their demise.

5. Volcano eruption theory: Due to the eruption of volcanoes, carbon dioxide is ejected in large quantities, causing a rapid greenhouse effect on the earth and killing food.

Moreover, volcanic eruptions release a large amount of salt, the ozone layer breaks, and harmful ultraviolet rays irradiate the earth's surface, causing the death of living things.

6. The theory of ocean ebbing: According to Buck, when the ocean ebbs and land borders, organisms come into contact with each other, thus causing the extinction of certain types of organisms.

For example, kangaroos can survive on island continents like Europe, but they are extinct when they encounter other animals on the South American continent.

In addition to the relationship between eating and being eaten, there are also problems of infectious diseases and parasites.

7. Warm-blooded animals theory: Some people think that dinosaurs are warm-blooded animals, so they may not be able to withstand the cold weather of the late Cretaceous and may not survive.

Because even if dinosaurs were warm-blooded, their body temperature was still not high, probably similar to that of living sloths. To maintain such a body temperature, they could only survive in tropical climate zones.

At the same time, dinosaurs' respiratory organs were not perfect and could not fully supply oxygen, and they did not have thick hair to prevent loss of body temperature, but they easily lost a lot of heat from their long tails and legs.

The difference between warm-blooded animals and cold-blooded animals is that if the body temperature drops below a certain range, physical energy must be consumed to raise the body temperature, and the body will quickly become weak.

Their bodies are too large to enter caves to avoid the cold, so if the cold days last for a few days, they may freeze to death due to exhaustion of energy.

8. Cannibalism theory: Some people believe that the real cause of the extinction of dinosaurs is the result of them killing each other - carnivorous dinosaurs feed on herbivorous dinosaurs, the number of carnivorous dinosaurs increases, and the number of herbivorous dinosaurs naturally decreases, and finally disappears.

The carnivorous dinosaurs killed each other because they had no meat to eat, and finally died together.

9. Oppression theory: The rapid increase in the number of dinosaurs caused the extinction of herbivorous dinosaurs when plants were limited. Then the carnivorous dinosaurs that relied on eating herbivorous dinosaurs also died due to lack of food.