WHY DID THE DINOSAURS DIE OUT? |
Dinosaurs remained the dominant land animals for approximately 165 milllion years. Yet, one the greatest unsolved mysteries of all time is why suddenly, in geological time, did the dinosaurs become extinct at the end of the Cretaceous period.
It was not just the Dinosaurs that became extinct at this time; the giant flying reptiles (the pterosaurs), the large marine reptiles (such as the plesiosaurs), the great spiralled ammonites and the microscopic calcareous sea plankton also became extinct.
Because large numbers of species became extinct at one time, the end of the Cretaceous is identified as a mass extinction. This is a time when numerous species of organisms, which may not be related, died out.
Many scientists have devoted their lives to explaining this strange event. Some of the theories concentrate on what happened to the dinosaurs alone, and fail to recognize the extinction of other species. For all of these species to have become extinct at the same time, means that what ever happened, happened on a global scale, and must have been catastophic in origin.
Numerous catastrophic theories have been proposed, the three leading ones being,
However, there is very good evidence that shows that dinosaurs were in a gradual decline long before the end of the Cretaceous. Indeed, only approximately 30 species of dinosaur actually made it to the end of the Cretaceous.
So what happened? The simple answer is that no-one knows. Dinosaurs may indeed have been in decline before the end-Cretaceous event took place. And there certainly was a meteorite impact and extensive volcanic activity at the time as well. Did both the long-term and short-term processes interact?
To learn more about what happened at the Cretaceous boundary,
please follow this link.
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