1. What caused the extinction of the dinosaurs?

2. The K-T boundary extinction event took place 65,000,000 years ago, and is merely one in a long line of mass extinction events. The chief reason for its fame is that it ushered out those perennially popular beasts, the dinosaurs. Many explanations have been given for this mass extinction, the most widely known being a massive impact caused by a bolide, or meteorite (meteorites are meteors which have impacted on the surface of a planet or other body). This idea has proved popular with television programme makers and the general public alike. This is probably because 1,000 years of C02 poisoning by wide-ranging volcano systems lacks the dramatic effect and neat ending produced by computer generated acts of planetary penetration. The first theory of the dinosaur extinctionThe K-T theory

3. Secondary Theory on the dinosaur extinction Volcano theory Volcano Chain Reaction Theory: Some believe that the large numbers of volcanoes was having the largest chain reaction ever seen. Every single volcano at that time should have become active and then the lava would kill the dinosaur. Conflict: A volcano chain reaction is rather unrealistic. What are the odds of all the volcanoes should become active at one time. Why was the fish and the mammals not killed, a worldwide volcano chain reaction would defiantly kill all species on earth.

4. Asteroid theory • Did a collision with a giant asteroid or comet change the shape of life on Earth forever? • It is widely agreed that such an object -- 10 kilometres across -- struck just off the coast of the Yucatan peninsula 65 million years ago. • According to scientists who maintain that dinosaur extinction came quickly, the impact must have spelled the cataclysmic end. • For months, scientists conclude, dense clouds of dust blocked the sun's rays, darkening and chilling Earth to deadly levels for most plants and, in turn, many animals. Then, when the dust finally settled, greenhouse gases created by the impact caused temperatures to skyrocket above pre-impact levels. • In just a few years, according to this hypothesis, these frigid and sweltering climatic extremes caused the extinction of not just the dinosaurs, but of up to 70 percent of all plants and animals living at the time.

5. Ice age Theory: An ice age could have come and then all the dinosaurs would freeze to death. Conflict: Scientist have not found a single trace of ice age in the period the dinosaurs lived

6. References http://www.bbc.co.uk/dna/h2g2/A706862 http://library.thinkquest.org/22973/library/dieout.htm http://web.ukonline.co.uk/a.buckley/dino.htm