Another point of view. In this months (December 2015) Scientific American there is an article about the end of the dinosaurs. The author and his colleagues are still looking at the asteroid strike as being the main cause of the death of the dinosaurs. However, they are looking at why the asteroid really did cause it. They have studied the diversity of species leading up to the extinction. It seems that most of the meat eating dinosaurs had a relatively large diversity. But the diversity of the large plant eaters was much reduced. So when the asteroid struck it damaged the large plant eaters more than the meat eaters, and that caused the collapse. They had a conference where 11 scientists sat down to discuss the extinction and found that they all agreed on this scenario.
Of course the Deccan Traps could have helped the event along, but the reason for the extinction was that the lack of diversity in the large plant eaters caused a large bottleneck in the food chain.
Of course they don't really know what caused the loss of diversity in the plant eaters, but they think the extinction might not have happened if they had been more diverse.
Bill Gill
