Dinosaurs have been the largest reptile-related animals on our planet so far. They are considered a type of prehistoric warm-blooded reptiles, related to current reptiles and even birds, but very different. They lived for approximately 160 million years, in the Mesozoic era, which is divided into three periods: Triassic, Jurassic, and Cretaceous. A long time ago they disappeared from the face of the Earth, but what happened to make these great animals cease to exist? This is a question that, really, we still ask ourselves, since there are several scientific theories about it.
If you want to know why the dinosaurs became extinct , keep reading this AgroCorrn article in which we present the different theories in detail and more curiosities about it.
Theories of the extinction of dinosaurs
When and how did the dinosaurs become extinct? It is one of the most frequently asked questions that still revolve around these animals of the past. Although science has already established a dating and a reason for this situation, nowadays thanks to the advancement of science, more details and results of studies on it appear and more theories have been presented and, even, a possible change of date in some cases.
The date of the extinction of the dinosaurs is considered to be around 65 million years ago . But, what is the most accepted theory of the extinction of dinosaurs by the scientific community? For several decades, it was established that the most probable thing is that the impact of a meteorite or asteroid on Earth made these giants that dominated the planet for so long disappear. However, as we have mentioned, there are more possible causes of this and, today, these are the most probable theories :
- Meteor or asteroid
- Volcanic activity
- Climate change
Next, we explain each of these possible theories of the disappearance of the dinosaurs.
Theory of the meteorite in the extinction of the dinosaurs
Between the end of the 70s and the beginning of the 80s, the theory of the meteorite or asteroid of 12 km in diameter that impacted on Earth, specifically in the area of the Yucatan peninsula in Mexico , was proposed as the cause of the extinction of the dinosaurs .
A geological layer or stratum rich in iridium was discovered, occupying the entire planet and dating from the time of the great extinction. This chemical element is not commonly found on the surface of the Earth, but it is found in the magma inside it, as well as in this ancient layer at great depth and in meteorites. As this element is very toxic and radioactive, the scientists considered that when a large meteorite or asteroid , rich in this element, and by raising large amounts of it from the inner layers of the planet, this material expanded throughout the Earth, ending the life of many living beings and extinguishing a large part of the dinosaurs, but it was not the only cause, but a chain reaction took place.
The great Chicxulub crater was discovered in Mexico , in the Yucatan Peninsula, and its age has also been dated to about 65 million years ago and, therefore, it is believed to be the point where the large asteroid that expanded the layer of iridium found and that ended up causing this great catastrophe.
Thus, the mass extinction of the dinosaurs was caused by the meteorite that hit Mexico. However, it was not the impact itself that killed so many beings, but it produced chain reactions to the point of extinguishing most of the life on the planet. The reactions that caused the death of the dinosaurs were, in this order, the following:
- The very impact that extinguished the dinosaurs in that area.
- The explosion or shock wave that produced large impacts and phenomena such as giant tsunamis across much land.
- The toxicity and radioactivity of iridium and other elements that were expelled from the innermost layers of the Earth due to the ejection that produced the impact of the meteorite.
- The large increase in temperature, which was calculated to be several times that of the sun, caused massive fires even thousands of km away from the origin of the impact.
- The thick and extensive layer of minerals and other elements that formed in the sky, as a result of the ejection of the impact and the gases resulting from the fires. Mainly, the ceiling was covered with gypsum, a material that contains sulfates and that at that time covered a large part of the Yucatan peninsula. The gypsum volatilized and converted to sulfates rose into the atmosphere in large quantities and this caused that sunlight could not reach the surface of the Earth. When the sun’s rays were blocked, photosynthesis (both on land and in the oceans) was stopped and there was great damage to food websIn addition, the animals could barely see, which would make it more difficult to find food and, as if that were not enough, after a few days the temperatures plummeted (about 10ºC) producing freezing in much of the planet. Thus, by one reaction or another, the living beings of the time were slowly dying another large part of the remaining life on the planet. With the passage of time this layer was dissolving, partly falling to the ground, allowing the sunlight to return enough for life to resurface from the few survivors that were
Theory of volcanoes as a cause of the extinction of dinosaurs
Another of the theories that most support the scientific studies carried out to date is that the volcanoes killed the dinosaurs . Evidence has been found that at the time of this extinction there was great volcanic activity , which lasted for a long time without interruption, especially in the part of India. In fact, these eruptions covered more than 2.6 million square kilometers of lava in India.
Such a catastrophe is considered to have killed all the animals in this part of the Earth. In addition, since the magma inside the planet and, consequently, the lava from volcanoes is rich in iridium , adding the ash and toxic gases expelled during the constant eruptions, all together, could cause the dinosaurs to disappear . The difficulty for sunlight to reach the Earth’s surface, the increase in greenhouse gases and the toxicity of the air itself, from which oxygen was reduced, were a perfect mix to prevent many species from surviving this era. .
Learn more about the Types of volcanic eruptions with this other post.
Why the dinosaurs disappeared: climate change theory in the Cretaceous
Finally, the latest theory accepted by the scientific community is that of climate change during the Cretaceous . There is various paleontological evidence, both in geological strata and in animal and plant fossils, that in this last part of the age of the dinosaurs there was a chain of cataclysms, such as earthquakes, tidal waves and a marked drop in temperature that caused extreme climatic changes. .
In addition, the level of the planet’s waters dropped significantly due to the significant drop in temperatures. Another aspect of an important change in the environment of that time, to which these large animals could not adapt in time.
Why Dinosaurs For Kids Are Extinct
This is a topic that many children want to know about, because as soon as they begin to discover these animals of the past, they are usually fascinated by everything around them and this particular aspect can be somewhat complex to explain.
If ever a child asks you why the dinosaurs disappeared, you will have to explain the above, but in a really simple way and encourage them to read about it and continue learning. Thus, in summary and in a simple way, the extinction of the dinosaurs for children can be explained in the following way.
According to paleontologists, who are the scientists who study and interpret the past of life on Earth thanks to the fossils they unearth, there are three possible ways that dinosaurs could disappear:
- A giant meteorite: 65 million years ago a giant asteroid fell from space to Earth, impacting fully in a place where Mexico is now. The immense blow and the explosion caused the end for all the animals in the area but, in addition, it caused the air of the planet to become very toxic, there were tsunamis and fires and the sunlight was covered for a long time, ending with even more life from the rest of the planet.
- Volcanoes: many millions of years ago, before we appeared, several volcanoes were erupting, exploding and pulling magma from the interior of the Earth to the surface. For many years in a row the volcanoes did not cease to be active and the result was that, apart from the lava devastating all the surrounding territory killing life, also the ashes and the expelled gases prevented the sunlight from reaching correctly and that the air became toxic, causing the end of life, far beyond where the lava reached.
- Climate change: another possibility why the dinosaurs disappeared is that in that era the climate changed in an extreme way and many species could not adapt to these changes in time to survive, so they became extinct, and among them the dinosaurs. The temperature dropped a lot and the humidity and other climate factors also changed. In fact, climate change also happened in the two mentioned catastrophes: the impact of the asteroid and the volcanoes; so it could be complementary.
Animals that survived the extinction of the age of dinosaurs: mammals
One of the most important survivors was the Mesodma , a now extinct genus of mammals. Specifically, they appeared in the Cretaceous and became extinct in the Paleocene. They were mammals the size of mice and of which there is scientific evidence that they survived the great extinction.
Mammals appeared almost at the same time as dinosaurs and lived with them throughout the period known as “the age of dinosaurs.” It was thanks to the extinction of the latter and the survival of these small mammals and others like them, that mammals evolved , diversified and expanded into large animals.
Thanks to all this, we are here today as a dominant species. If the meteorite had not produced such reactions, that is, if it had not fallen right in this area, it is very likely that many dinosaurs would have survived and mammals could not have evolved in such a way.
To finish, if you want to discover much more about dinosaurs, we recommend you start with this other interesting AgroCorrn article in which we talk about carnivorous dinosaurs: names, types, characteristics and images .