by A W Drake

Created on: April 04, 2009   Last Updated: April 07, 2009

The extinction of the dinosaurs occurred during then end of the Cretaceous era, around 65 million years ago, and caused the loss of up to 70 percent of all life on the planet. Although this event was not the only mass extinction in Earth's history or the most severe, dinosaur extinction has spawned a range of theories from the credible to the less than believable.

Ice Age

If an Ice Age occurred during the Cretaceous era it is unlikely the dinosaurs would have been able to survive. Water and large land masses would have been locked in ice, and as dinosaurs were thought to be cold blooded they would probably not have been able to cope with sub zero temperatures.

Disease

It is difficult to see how one disease could be so prevalent as to wipe out large swathes of the animal population, travel vast distances and kill off both land and marine species as well as plant life. It is not likely that dinosaurs became extinct through disease alone.

Climate Change

If a gradual change in the earth's climate occurred with a cooler, drier environment and an adapting plant life, possibly the dinosaurs would not have been able to adapt quickly enough to survive. The fossil records of dinosaur skulls show they could only have had small brains. This indicates dinosaurs relied on automatic body responses rather than the cognitive, decision making responses warm blooded animals are known to make. Therefore a changing environment could have been difficult for dinosaurs to adapt to and the average dinosaur would not have been able to compete effectively with warm blooded animals.

Supernova

A supernova is a star that explodes with enough energy to keep our sun burning for six billion years. If the Earth was hit by the resulting radiation from a nearby supernova it would have destroyed all dinosaur life. There is no evidence for a supernova causing the extinction of the dinosaurs, and it is difficult to see how anything would have outlived such an event.

The Volcano Theory

It is known that volcanic activity was widespread during the Cretaceous era, and is a credible reason why the dinosaurs became extinct. The Deccan Traps in western India and areas in the Pacific Basin are likely sites for increased volcanic activity at this time.

The consequences of large scale volcanic activity would have led to a nuclear type winter with ash and gasses added to the atmosphere, depleting sunlight and creating difficult conditions for dinosaur species. Hydrochloric acid in particular would have broken down the

• 1
• 2
• 3
• Next Page >>