Doubt Raised on the Cause of Dinosaur Extinctions
A mere 65 million years ago, Tyrannosaurus Rex, a forty-five foot scavenging carnivore, Triceratops, a mellow-mannered, five-ton herbivore, and many other species of dinosaur roamed the planet. Due to the well-preserved fossil record, paleontologists are able to determine specific areas where these giants wandered, their probable diet, and enormous size, but the cause of their somewhat sudden extinction is still a mystery. Due to further investigation, paleontologists now believe that the extinction was possibly not so sudden after all.
A bit of history may bring some clarification to the issue. Many changes had occurred during the three periods of the Mesozoic Era with each introducing new species of plants, marine life, and land animals, as well as each experiencing the dying out of some species.
Even though the Mesozoic Era is considered, “The Age of Dinosaurs”, few were visible during the Triassic Period. The one world continent, referred to as Pangaea, began to separate. The climate became warm and arid. Large dinosaurs certainly did not exist at that time; insects that had survived the previous extinction, reptiles, frogs, crocodiles, turtles, snakes, the first mammals and a few small dinosaurs represented animal life.
The Jurassic Period brought further separation of the continents and the first birds became apparent. Forests flourished in the tropical climate and dinosaurs, like Stegosaurus and Apatosaurus began their dominance.
Montana, Wyoming, and Colorado have proved to be treasure chests for fossils of the Cretaceous Period. The dinosaurs became increasingly colossal in size, some measuring fifty feet in length and weighing up to seven tons. Plant life thrived; more food being available for the herbivores resulted in healthy herds; consequently, large herds resulted in plenty of food for the carnivores. In this seemingly ideal environment, why would they all die?
Extinctions are not unusual. During the Permian Period of the Paleozoic Era, preceding the Mesozoic Era, 95% of all marine life and 70% of all land life disappeared. Although the reason for that extinction is still being debated, climate change is the generally accepted theory.
Many paleontologists believe the dinosaur extinction was not due to one catastrophic event, but that the extinction took place over many years. As climate changes occurred, species evolved, and food sources modified, some species did not adapt well and eventually died out; the introduction of new diseases could also have played a significant role. Furthermore, violent earthquakes and volcanic eruptions were frequent; the ash alone would have claimed thousands.
Many asteroids have bombarded the planet over the years evidenced by the still visible craters. The unusually large asteroid that struck the Yucatan Peninsula sixty-five million years ago, leaving an enormous crater on the sea floor, continues to be a widely accepted theory as to the dinosaur’s finality. The dinosaurs alone did not suffer this disastrous event; two-thirds of all species became extinct.
The mass extinction of plant, animal, and marine life is nothing new; the earth has its own mysterious timetable set to renew itself. Another mass extinction will most likely occur at some point in the future.
