Humans first appeared 2.5 million years ago. But what did the earth look like before the existence of humans? What were there on earth? Dinosaurs, we have only heard of them, but we have never seen their existence on earth. What happened to dinosaurs? Roughly 240 million years ago, Dinosaur was the Rockstars on the earth. We have a perception of a dinosaur to be large in size, have big teeth, drag their large tails on the ground and look scary. But what is really a dinosaur? What happened to them? It is believed that an asteroid from outer space killed them. Is this reason behind their disappearance true or still a mystery?
The era of dinosaurs
They lived in the Mesozoic era, and it had a single landmass, with a relatively hot and dry climate, where the land was covered with large desserts with no polar ice caps. During the Mesozoic era, which is known to be the age of dinosaurs, there were 3 different periods known as Triassic, Jurassic, and Cretaceous periods. In these 3 different periods, lived different varying from small and big in size.
There were more than 700 species, roamed inland and flew in the sky. Some were herbivores who ate plants, while some were carnivores who ate small animals and other dinosaurs. They weighed about 100 tonnes which is similar to the weight of 15 elephants. They existed on the earth for about 165 million years and vanished around 66 million years ago.
What happened to dinosaurs?
The landing of asteroids
Nobel prize-winning physicist Luis Walter Alvarez and his son a geologist called Walter published a theory about a large asteroid colliding with the earth. Although their theory caused controversies, it is presently accepted widely as the reason for the disappearance of dinosaurs. Asteroids are large rock bodies that orbit the sun, ranging from a few hundred meters in diameter.
An asteroid had hit the earth, in the parts of Mexico and they have identified the crater buried on the seafloor off the coast of Mexico and it has been confirmed that it was at the same period of the extinction of dinosaurs. It is thought to have between 10 to 15 kilometers wide and colliding with earth has caused to create more large crater which was 150 kilometers in diameter.
When asteroids land on earth, it is called a meteorite. The scientists believe that it struck the earth at 40,000 miles per hour and released energy that was more than 2 million times, more powerful than a nuclear bomb. And as a result, the earth’s surface became hot with wildfires worldwide and made the planet into darkness and the remains and dirt clouded the atmosphere.
High tsunamis would have created washing over the continents and would have drowned many forms of life. This would have triggered volcanic eruptions and earthquakes.
As the planet’s atmosphere was filled with remains, the darkness remained for months and years, resulting in no sunlight. This lead the earth to freeze and plants had no way of surviving. This impacted the eco-systems killing the plant-eating dinosaur, and as a result, the carnivore dinosaur who depended on the plant-eating dinosaurs too died.
Climatic changes made life hard
Apart from the asteroid, the earth was already experiencing climatic changes, which made things hard for the life on the earth. There was volcanic activity in a place, which is presently central India. For 2 million years, a huge amount of volcanic activity was going on making a major impact on the global climate. It was a single landmass, but these changes made the earth split apart from each other creating big oceans.
But in the late Mesozoic Era, evidence showed that the planet slowly became cooler, and caused the ice to form, making the oceans colder. The dinosaurs were cold-blooded, which means they obtain body heat from the sun and air so that they were not able to survive in such climates.
Their evolution to modern birds
During the period of the Cretaceous, plants were not much affected because their seeds and pollen were able to survive harsh periods for longer. And after the extinction of dinosaurs, the plants dominated the earth, and animals who weighed more than 25 kilograms died out. All the land dinosaurs died but the flying dinosaurs survived, and they have evolved to be modern birds.
Although the central mystery appears to be solved, it remains to be not fully agreed upon and the remains are continuing to be found that says on how dinosaurs lived and died. And the birds have been identified as descendants of the dinosaur. And the theories regarding intelligence and behaviors continue to change. If there were no asteroid, dinosaurs might have survived a little longer. Dinosaurs remain the largest land animals ever to have lived.
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