Dinosaurs are reptiles that lived on our planet earth over 250+ million years ago. They evolved over 3 major periods, the Triassic, Jurassic, Cretaceous. The species survived for about 160 million years which is 64times more than the time humans have been on the planet. Being huge in size, they were top predators on land across the globe with no opponent of their equal footing. Most of them were carnivores who ate their own species while some were herbivores surviving on a plant-based diet alone.
They started small in size, about the size of household pets. Later on, they evolved into much bigger size with heights above 18 meters. The titanosaurus is claimed to have been the biggest dinosaur that existed with a long neck and its weight measuring to over 100 tonnes. The tyrannosaurus rex is another meat-eating dinosaur that weighed almost 60 tonnes or even more. There were about 900 unique dinos/dinosaurs that lived through the three major periods.
The earth's geography during those years was completely different from what it is today. During the Triassic Period, the beginning age of dinosaurs, the entire earth’s landmass was clubbed into one supercontinent called Pangea. Soon, during the 160 million years of dinosaurs’ existence, the landmasses, called the tectonic plates in geological terms, started drifting from each other breaking Pangea, the Supercontinent, into smaller pieces/continents which separated the dinosaurs altogether. Dinosaurs thrived and lived in every continent up to the end of the Cretaceous period which is when they went extinct altogether.
What actually killed the dinosaurs still remains a mystery. Maybe it was one or two asteroids that struck earth, raising the temperature of the earth to extremes which might have made nearly 75 percent of the total population of life on the planet unable to sustain themselves e, leading to the extinction of many species including the giant dinosaurs. Some claim that their eggs became prey to almost every animal which contributed to the decreasing number of newly hatched offspring over time. Another theory is that there were too many male dinosaurs in relation to females. Infertility specialist Sherman Silber, supporting this theory, asserted that dinosaurs perished because they couldn’t find mates. According to Wallace Tucker and paleontologist Dale Russell, a supernova could have been the cause of the extinction which completely wiped the dinosaurs off the face of the earth in an action-packed mass devastation.
However, the parent reason is that there was a meteorite that struck earth causing abnormal reactions on earth and significantly changing the environment which eventually led to the mass extinction. It didn't happen all at once. It happened over a course of thousands of years, slowly killing all the dinosaurs.
The fossils of dinosaurs have been found mostly from three major locations- the high-altitude badlands of China, Argentina and North America. North America holds some of the largest number of dinosaurs’ fossils.
Though the dinosaurs have long perished, its descendants still are pretty much alive in the form of birds. All the non-avian dinosaurs went extinct, but the avian dinosaurs evolved over the millennia into birds. Chicken, a domesticated bird, is also believed to have evolved from dinosaurs.
The crocodiles, the cassowaries, the tuatara, the sharks, sea turtles, ostriches, crustaceans, etc., all survived the factor that led to the extinction and are very much alive and present today.
5th Semester (Economics Honors)
Modern College, Piphema