Why did dinosaurs die?

The reasons for the extinction of dinosaurs are still being studied. For a long time, the most authoritative view has been that the extinction of the dinosaurs was related to a large meteorite 65 million years ago. According to research, an asteroid with a diameter of 7-10 kilometers fell on the surface of the earth at that time, causing a big explosion and throwing a large amount of dust into the atmosphere, forming a dust fog that blocked the sky and the sun, causing the photosynthesis of plants to temporarily stop. The dinosaurs became extinct as a result.

The asteroid impact theory quickly gained support from many scientists. In 1991, the discovery of an ancient meteorite impact crater in Mexico's Yucatan Peninsula further confirmed this view. Today, this view seems to be a foregone conclusion.

But many people are skeptical of this asteroid impact theory, because the fact is: frogs, crocodiles and many other animals that are very sensitive to temperature have withstood the Cretaceous and survived. This theory cannot explain why only the dinosaurs died. So far, scientists have put forward no less than a dozen hypotheses about the cause of the extinction of the dinosaurs, and the more exciting and dramatic "meteor collision theory" is just one of them.

In addition to the "meteor collision theory", there are the following main views on the extinction of dinosaurs:

1. The theory of climate change. 65 million years ago, the earth's climate changed suddenly and the temperature dropped significantly, causing the oxygen content of the atmosphere to drop, making it impossible for dinosaurs to survive. Some people also believe that dinosaurs were cold-blooded animals. They had no hair or warm-keeping organs on their bodies and could not adapt to the drop in earth temperature, so they all froze to death.

2. The theory of species struggle. At the end of the dinosaur era, the first small mammals appeared. These animals were rodent carnivores and may have fed on dinosaur eggs. Due to the lack of natural predators, the small animals grew in numbers and eventually ate up all the dinosaur eggs.

3. The theory of continental drift. Geological research has proven that in the era when dinosaurs existed, there was only one continent on the earth, namely "Pangaea". Due to changes in the earth's crust, this continent experienced major divisions and drifts during the Jurassic Period, which eventually led to changes in the environment and climate, and the dinosaurs became extinct as a result.

4. Theory of geomagnetic changes. Modern biology has proven that the death of some organisms is related to magnetic fields. Creatures that are sensitive to magnetic fields may become extinct when the Earth's magnetic field changes. It can be inferred that the extinction of dinosaurs may be related to changes in the earth's magnetic field.

5. The theory of angiosperm poisoning. At the end of the Age of Dinosaurs, gymnosperms on the earth gradually disappeared and were replaced by a large number of angiosperms. These plants contained toxins that were not found in gymnosperms. The huge dinosaurs ate a lot. Ingesting a large amount of angiosperms led to the accumulation of toxins in the body. Duo was finally poisoned to death.

6. Acid rain theory. There may have been strong acid rain at the end of the Cretaceous, which dissolved trace elements including strontium in the soil. The dinosaurs directly or indirectly ingested strontium through drinking water and food, and suffered acute or chronic poisoning. The last batch of them died.

There are far more hypotheses about the reasons for the extinction of dinosaurs than the above. However, the above hypotheses have many supporters in the scientific community. Of course, each of the above statements has imperfections. For example, the "climate change theory" does not clarify the causes of climate change. After investigation, some small coelurosaurs among dinosaurs were enough to compete with early small mammals, so there are loopholes in the "struggle of species theory". In modern geology, the "continental drift theory" itself is still a hypothesis. "Angiosperm poisoning theory" and "acid rain theory" also lack sufficient evidence. Therefore, the real reason for the extinction of dinosaurs still needs to be further explored.