By Ashraf Naushahi

In the science of geology, the history of the planet Earth is studied by dividing it into several eons, eras, periods, epochs and ages. The Mesozoic Era was a geological era on the planet Earth from 252 to 66 million years ago. It is also named as the "Age of Reptiles" by geologists. It was an era containing 186 million years, which were divided into three periods: Triassic, Jurassic and Cretaceous.

According to geological theories and discoveries, the periods of Mesozoic era were the periods of big creatures called "dinosaurs". These creatures became extinct and disappeared in the beginning of Cenozoic Era, that followed the Mesozoic Era. Scientists as well as geologists have developed many different theories about the extinction of dinosaurs. Since the discoveries of fossils it has been surprising for the geologists and other scientists that how creatures as big and huge as dinosaurs became extinct. Fossils are remains and traces of creatures once found on the Earth. Fossils of dinosaurs were first found in the beginning of the 19th century.

Till the early years of 21st century, fossils and skeletons of dinosaurs were collected in a large number for display in numerous museums the world over. Not only that but dinosaurs also became interesting subjects of stories, novels, television shows, and movies. Jurassic Park was a science fiction movie made in 1993 about dinosaurs. It became one of the most famous films in the history of cinema. However, keeping television shows, films and science fiction aside, there are several theories in geology about the extinction of dinosaurs.

The word "dinosaur" was first coined by geologist Professor Richard Owen in 1842, to describe species of reptiles. These species or creatures were vertebrates found mostly in Jurassic and Cretaceous periods. Types of dinosaurs were diverse and more than 300 different types have been discovered and named during the past two centuries. According to geologists almost 600 different types of dinosaurs could be discovered as the fossils from the periods of Mesozoic Era. As different dinosaurs ate differently, geologists have divided these creatures into herbivorous, carnivorous, insectivores and omnivores.

Fossils of dinosaurs were found in all the seven continents and in various environments. Continents were connected millions of years ago, therefore, dinosaurs could go from one continent and region to another. From fossils scientists have discovered that dinosaurs could move on the surface of the Earth but could not fly in the air. At the end of Cretaceous period, 66 million years ago, big dinosaurs became extinct but some small species as crocodiles or lizards remained.

It has been puzzling to the scientists since the discoveries about dinosaurs that what happened to such big creatures. It is difficult to answer because knowledge and theories about dinosaurs depend on discoveries of fossils. In museums, skeletons of dinosaurs were re-made by arranging bones of dinosaurs, which were found as fossils. Scientists understand that dinosaurs evolved as vertebrates. Some big change in the climate of those periods could be a cause of extinction. Other possible causes theorized by geologists are; volcanic effects, comet impact, or radiations harmful to dinosaurs. In short, scientists and geologists as yet could not get an answer of what exactly happened to dinosaurs. However, about what happened to dinosaurs, scientific research is continued for developing scientific theories.

Published in Young Nation Magazine on October 28, 2017