The earth was a much different place 65 to 150 million years ago when dinosaurs roamed the earth. Many changes in the planet’s climate, along with geological transformations, occurred during the Triassic, the Jurassic, and the Cretaceous periods of the Mesozoic Era, also known as the Age of the Reptiles. Each period presented new species of plants, marine life, and land animals, as species that could not adapt to each new environment became extinct; however, what could have possibly caused a worldwide eradication of life at the end of the age?
At the latter part of the Cretaceous period, dinosaurs had become massive. Plant life flourished providing a healthy diet for the herbivores; in turn, the carnivores were supplied with an endless supply of meat to sustain their enormous size. The food chain was complete with a tropical environment; then, it all ended. Once thought to have been an almost instantaneous extinction, paleontologists have now determined that many factors may have contributed to the mass extinction.
Although mass extinctions are not common, scientists believe they have only occurred five times during the earth’s history. For example, during the Permian Period of the Paleozoic Era, just preceding the Mesozoic Era, 95% of all marine life and 70% of all land life disappeared. A drastic climate change at the time has been credited with the extinction. In the late Devonian period, a mere 370 million years ago, life also suffered a likewise demise; the cause has not yet been determined.
Paleontologists today believe the dinosaur extinction was not due to one catastrophic event, but that the extinction took place over many years and caused by numerous contributing events. Severe climate changes had occurred over the years. Since the climate has everything to do with proper plant growth, plant eating species experienced famine as food sources became scarce. This would also have affected the meat eating species, as the food chain became interrupted.
In the few short years that man has lived on the planet, plagues have caused millions of deaths. With the changing world million of years ago, disease could have played a significant role in the elimination of some species. Though this theory would have probably taken place over a long period of time, dinosaur populations would have been infected and gradually decreased.
It is also important to understand that the earth itself was undergoing extreme physical changes during the era. The earth’s tectonic plates were on the move separating the enormous land mass we now recognize as the seven continents. The violent earthquakes caused by this movement could have been responsible for the death of millions of land animals.
Volcanic eruptions were also frequent during the Mesozoic Era. Mountains of ash spewing into the air would have filled the atmosphere and blanketed the surrounding landscape killing the existing plant life. Furthermore, the animals foraging for plants would have ingested large amounts of ash into their stomachs, as well as breathing the gaseous elements and miniscule rocks into their lungs. Volcanoes alone could have claimed a large percentage of all life.
Asteroids have bombarded the planet over the years wreaking havoc with the atmospheric conditions and causing massive tsunamis. There is visible evidence of an unusually large asteroid that struck the Yucatan Peninsula sixty-five million years ago leaving an enormous crater on the sea floor. The asteroid probably brought finality to the life of the dinosaur which was already decreasing in population. The dinosaurs were not the only species to be the victims of the catastrophe; two-thirds of all species became extinct following the asteroid strike.
Mass extinction is not a new occurrence; the earth will renew itself again although an exact timetable cannot be calculated.