All different species of dinosaurs died approximately 65 million years ago at the end of Mesozoic era. Their extinction has been a mystery but they might have become extinct due to climatic changes, diseases and geologic events.
There is evidence to show that there was temperature drop at the end of Mesozoic era and the sea level fell. Such a sudden change in temperature might have damaged the plant life which formed the basis of the dinosaur’s food chain.
There are some theories put forward for the dinosaur’s extinction:
1. Continental drift that altered the climate.
2. Diseases that has cleared the population of the species.
3. Large volcanic eruptions that destroyed all of the Dinosaurs.
4. Meteorites that has hit the earth destroying most of the flora and fauna on earth.
5. Small mammals appeared that had fed on dinosaur’s eggs, therefore depleted them to extinction.
According to the asteroid theory suggested by Luis and Walter Alvarez for dinosaur extinction, a collision by a large asteroid into Earth might have ended the Mesozoic era. A large 100 mile diameter asteroid called Baptistina was found to have collided with another asteroid in space and it broke into pieces around 160 million years ago. After 95 millions of years those pieces have reached earth and collided with it. This collision would have resulted in a large explosion that darkened the planet and made it hotter. Later, the extensive forest fire might have raised lot of smoke into the air that gradually cooled the earth. Thus climatic changes may have occurred.
The presence of iridium in the layer of rock called K-T boundary which means the cretaceous-tertiary boundary has made the scientists believe that a meteorites collision would be the real cause of the dinosaur’s extinction. Iridium is rarely available on earth’s surface but can be abundantly found in asteroids and meteorites.
But there are certainly some doubts about this asteroid theory as frogs, crocodiles and other marine reptiles could survive after the disaster in that period. If the climatic changes have removed dinosaurs completely how are these small creatures able to live till now?
We need to wait for a correct and real reason for the dinosaur’s extinction and probably we will come to know about it one day.