Dinosaurs were a specific group of animals that lived in the Triassic era. They were reptiles that belonged to a subclass named archosaurs. Scientists describe the archosaurs as the class of ruling reptiles. The class also entails crocodiles and birds. The study of dinosaurs began in the 19th century where a group of scientists made the discovery of a large reptile that resembled a large lizard. Sir Richard Owen is the English paleontologist that came up with the name dinosaur. The term was derived after the paleontologist made the discovery that the animal belonged to a special reptile group that existed in the past. After the first discovery of the animal, numerous fossils of the reptile have been discovered in different parts of the globe. The fossils had different appearances but appeared to belong to one species.
             Mass extinction events have occured five times in the history of the earth. The first event took place during the final period of the Ordovician. The fossil record indicates that 60% of the genera that belonged to the marine and terrestrial life became exterminated. The second extinction event took place almost 360 million years during the final part of the Devonian period. The natural environment nurtured reefs for thirteen million years. It turned and became hostile leading to the extinction event. The final years of the Permian, extinction discloses that the earth lost life. Scientists explain that 80-95% of marine life species became extinct (Paul, 2010). The final parts of the Triassic period claimed half of marine invertebrates. Research indicates that 80% of the land quadreplates also died. The cretaceous is also an extinction period that took place sixty-five million years ago. This period is associated with the extinction of dinosaurs from the earth. Paleontologists explain that no large animal managed to survive during the period.
             The broader understanding of the cretaceous extermination plays a large ...