How did dinosaurs become extinct from Earth

They are very large reptile animals that lived on Earth since ancient times, and they were among the most widespread groups of animals on our planet f

Dinosaurs

They are very large reptile animals that lived on Earth since ancient times, and they were among the most widespread groups of animals on our planet for a period that scientists estimated to be approximately 160 million years. Disappeared dinosaurs - of all kinds - from the ground, suddenly, about 65 million years ago, The scholars differed as to determine the cause of extinction, where still there are many varying interpretations of the table, but a large part of the scientific community tends to The reason was in the collision of a huge asteroid coming from outer space with the surface of the Earth, where the dust clouds scattered from the collision blocked the rays of the sun, and thus sudden and severe climate changes occurred on the planet, and many animals could not adapt to these changes, and the result was the extinction of all kinds of dinosaurs that It lived then, in addition to about 60% of all life on Earth at that time. 

Age of the dinosaurs

Dinosaurs appeared on Earth at the beginning of the Triassic period, about 230 million years ago, and they belong to the group of reptiles , which also includes turtles, crocodiles, snakes and lizards of various kinds. The diversity of dinosaurs increased at an accelerated rate over the post-Triassic eras, becoming one of the largest, most diverse and widespread animals on Earth. However, scientists can only identify these organisms through their fossils and fossils that are found with great difficulty, which makes studying them not easy. Nevertheless, scientists from 1824 to the present day have discovered more than a thousand species of dinosaurs that lived over the 160 million years of our planet's history. 

Many strange animals lived on Earth alongside dinosaurs, which people sometimes mistakenly think are dinosaurs, but in fact they belong to other classes of reptiles. A prominent example of these creatures is the so-called Pterosaurs, which are very large winged reptiles, whose wings were more than 10 meters wide.  Also, many strange giant reptile species lived in the seas , such as the long-necked plesosaur which was used to catch fish, and the mosasaur, which was the size of a whale with a length of more than 17 meters, which is considered one of the largest carnivorous creatures that lived on the planet in history. 

Theories about extinction

Although the scientific agreement is increasingly moving towards the idea that the collision of an asteroid with the Earth was the main factor behind the extinction of dinosaurs, there are many proposed theories that try to explain the disappearance of these organisms from the planet, which are very varied and uneven, the most important of which are:

• Asteroid collision: sediments discovered from the late Cretaceous period indicate that the Earth experienced a series of intense seismic waves during the extinction of the dinosaurs, an event that could be associated with a major asteroid collision. On the other hand, abundant quantities of iridium were discovered in the same sediments, which is a very rare chemical element in the Earth's crust, but it is widespread in the chemical formation of many outer space asteroids, in addition to that many compressed quartz crystals as a result of a high shock were discovered in The same classes, which strongly supports such a theory. In such a case, the shock resulting from the impact of the asteroid with the Earth will not be the main reason behind the extinction, but rather the debris of the asteroid, which most likely lifted in the form of giant dust clouds to the atmosphere, causing the sunlight to be blocked, thus reducing the temperature on the surface of the earth by a great extent Very much, it caused the destruction of vegetation and the elimination of many forms of life, in addition to causing severe climatic disturbances, such as thunderstorms, fire storms and the emission of infrared radiation in large quantities. 

• Volcanic eruptions: This theory is associated with the belief that the extinction of the dinosaurs was a gradual matter, rather than having occurred suddenly 65 million years ago, it could be an event that took hundreds of thousands or millions of years, as the evidence indicates the start of a series of eruptions of intense volcanoes in Western India (on the Dikan Plateau) from 68 million years ago and for more than two million years after that.  Volcanoes may have contributed to the extinction of dinosaurs in various ways, such as spreading toxic sulfur gas into the air, or blocking sunlight from plants due to the dense smoke they released. 

• Continental drift: The theory of plate tectonics states that the continents are based on separate masses of land floating above the inner layers of the earth, and that these masses are constantly converging or moving away from each other, and it is possible that this phenomenon may have played a role in the extinction of the dinosaurs, where evidence indicates that The continents were drifting from the equator towards the poles during the Cretaceous period, which may have caused climatic changes in different regions, reaching up to six degrees Celsius in some areas. However, there are several flaws in this theory, such as its inability to explain why dinosaurs did not survive longer near the equator. 

• Poisonous plant: This theory suggests the emergence of poisonous plants in the last period of the Cretaceous period, when most species of plant-eating dinosaurs fed on them, which led to their poisoning and death, and then the death of the carnivorous dinosaurs because there were no longer any prey to feed on. However, this theory has been rejected by many scientists and researchers due to the difficulty of believing it. Poisonous plants spread in our modern era with many varieties and species, but they did not cause the extinction of any kind of living creatures, and this theory fails to explain the reason for the extinction of marine organisms at the end of the era Cretaceous, which would not have been affected by these poisonous plants on land. 

• Epidemic: This theory assumed the emergence of an infectious bacterium that infected all kinds of dinosaurs and spread among them, causing their death. This theory was described as weak. Because it is difficult to have a single germ that infects different and multiple types of dinosaurs that differ in their strength and ability to fight germs and diseases. 

• Egg thieves: The owners of this theory tended to assume the emergence of a rodent in the late Cretaceous period that fed on dinosaur eggs in a large and rapid manner, which led to the cessation of their reproduction, but many scientists found it difficult to accept this theory. 

Surviving dinosaurs from extinction

Although most evidence indicates that birds are the only creatures classified within the category of dinosaurs that have succeeded in surviving the Earth after the extinction of the Cretaceous period, there is a possibility that a small number of them survived for a short period after it, and continued to live in isolated geographical areas. There are not many signs that this is happening, and many scientists are still skeptical of it, but there are discoveries that could support it. Scientists have found in a rock formation in Montana, USA, on fossils of dinosaurs 1.3 meters above the rocky layer, during which the extinction of the Cretaceous period is assumed to have occurred, which means that some species of dinosaurs may have lived up to 40,000 years after the primary extinction. Nevertheless, discoveries such as these can be easily answered that the bones that have been found have been repositioned by climate factors, and have been accidentally transported into modern rock strata which, in fact, do not belong to them.